dry cooling systems1.2
TRANSCRIPT
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IntroductionWater demand from thermal power plants mainly for steam condensation(power plant cooling) can place a significant burden on limited local andregional freshwater supplies An approach to reducing this cooling waterdemand is the use of direct dry cooling which requires no consumptive
water use and can reduce a power plants water demand by up to95 percent Direct dry cooling uses air‐cooled steam condensers which
consist of a series of finned air‐cooled condenser tubes arranged in an
A‐frame configuration Steam is routed from the steam turbine to the
condenser where the heat from the condensing steam is rejected to theenvironment via the finned tubes Beneath these condenser tubes is anarray of fans which force a stream of air through the condenser
A major limitation to using this cooling technology is that air‐cooled steam
condensers are unable to maintain their performance during very hot
andor windy periods This directly affects energy production because areduction in condenser performance creates backpressure on the steamturbine and reduces electricity generation
Thermal Power Plant
A thermal power station is a power plant in which the prime mover issteam driven Water is heated turns into steam and spins a steam turbine which drives an electrical generator After it passes through the turbine
the steam is condensed in a condenser and recycled to where it washeated this is known as a Rankine cycleSteam is generated in the boilerof the thermal power plant using heat of the fuel burnt in the combustionchamber The steam generated is passed through steam turbine wherepart of its thermal energy is converted into mechanical energy which isfurther used for generating electric power The steam coming out of thesteam turbine is condensed in the condenser and the condensate issupplied back to the boiler with the help of the feed pump and the cycle isrepeated The function of the Boiler is to generate steam The function ofthe condenser is to condense the steam coming out of the low pressure
turbine The function of the steam turbine is to convert heat energy intomechanical energy The function of the condenser is to increase thepressure of the condensate from the condenser pressure to the boilerpressure The other components like economizer super heater air heaterand feed water heaters are used in the primary circuit to increase theoverall efficiency of the plant
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General Layout of Thermal Power Plant
The general layout of thermal power plant consists of mainly four circuitsas shown in [1] The four circuits are
1 Coal and Ash circuit2 Air and Gas circuit3 Feed Water and Steam circuit4 Cooling Water circuit
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1Coal and Ash Circuit
In this circuit the coal from the storage is fed to the boiler through coalhandling equipment for the generation of steam Ash produced due tocombustion of coal is removed to ash storage through ash-handlingsystem
2Air and Gas Circuit
Air is supplied to the combustion chamber of the boiler either throughforced draught or induced draught fan or by using both The dust from theair is removed before supplying to the combustion chamber The exhaustgases carrying sufficient quantity of heat and ash are passed through theair-heater where the exhaust heat of the gases is given to the air and thenit is passed through the dust collectors where most of the dust is removedbefore exhausting the gases to the atmosphere
3 Feed Water and Steam Circuit
The steam generated in the boiler is fed to the steam prime mover todevelop the power The steam coming out of the prime mover iscondensed in the condenser and then fed to the boiler with the help ofpump The condensate is heated in the feed-heaters using the steamtapped from different points of the turbine The feed
heaters may be of mixed type or indirect heating type Some of the steam
and water are lost passing through different components of the systemtherefore feed water is supplied from external source to compensate thisloss The feed water supplied from external source to compensate theloss The feed water supplied from external source is passed through thepurifying plant to reduce to reduce dissolve salts to an acceptable levelThis purification is necessary to avoid the scaling of the boiler tubes
4Cooling Water Circuit
The quantity of cooling water required to condense the steam isconsiderably high and it is taken from a lake river or sea At the Columbiathermal power plant it is taken from an artificial lake created near the plantThe water is pumped in by means of pumps and the hot water aftercondensing the steam is cooled before sending back into the pond bymeans of cooling towers This is done when there is not adequate naturalwater available close to the power plant This is a closed system where thewater goes to the pond and is re circulated back into the power plantGenerally open systems like rivers are more economical than closedsystems
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Working of the Thermal Power Plant
Steam is generated in the boiler of the thermal power plant using heat of
the fuel burnt in the combustion chamber The steam generated is passedthrough steam turbine where part of its thermal energy is converted intomechanical energy which is further used for generating electric power Thesteam coming out of the steam turbine is condensed in the condenser andthe condensate is supplied back to the boiler with the help of the feedpump and the cycle is repeated The function of the Boiler is to generatesteam The function of the condenser is to condense the steam coming outof the low pressure turbine The function of the steam turbine is to convertheat energy into mechanical energy The function of the condenser is toincrease the pressure of the condensate from the condenser pressure to
the boiler pressure The other components like economizer super heaterair heater and feed water heaters are used in the primary circuit toincrease the overall efficiency of the plant
Site Selection of a Thermal Power Plant
The important aspect to be borne in mind during site selection for athermal power plant are availability of coal ash disposal facility spacerequirement nature of land availability of water transport facility
availability of labor public problems size of the plant
The different types of systems and components used insteam power plant are as follows
(i ) High pressure boiler(ii ) Prime mover(iii ) Condenser (iv ) Coal handling system
(v ) Ash and dust handling system(vi ) Draught system(vii ) Feed water purification plant(viii ) Pumping system(ix ) Air pre heater economizer super heater feed heaters
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1CoalThe coal is obtained primarily from Wyoming This is done in most casesbut coal may also be shipped by trucks or by pipelines Inside the powerplant there is an unloading dock where the carts of the rail are heated tomelt the snow on the rail carts before unloading them The coal is stored inhuge heaps or piles of a half a mile in diameter The reason for stocking
this much of coal is because the loss due to loss of generation due to lackof coal is very high The upper layer of the coal heap has to be compactedto make it into a airtight surface to prevent loss of coal due to oxidationOther methods of preventing oxidation are by keeping it under water or byspraying chemicals on it
2 Coal handling In plant coal handling is a very important aspect of power plant
safety In variably the coal is not exposed as it can pollute the air andrelease poisonous gases like carbon monoxide The coal from the heaps ismoved into the plant by means of long conveyors that are electricallyoperated There are many different types of conveyors and coal-handlingdevices like screwing conveyors bucket elevators grabbing bucketconveyors etc
3 Coal CrusherBefore the coal is sent to the plant it has to be ensured that the coal is ofuniform size and so it is passed through coal crushers Also power plants
using pulverized coal specify a maximum coal size that can be fed into thepulverizer and so the coal has to be crushed to the specified size using thecoal crusher Rotary crushers are very commonly used for this purpose asthey can provide a continuous flow of coal to the pulverizer
4PulverizerMost commonly used pulverizer is the Boul Mill The arrangement consistsof 2 stationary rollers and a power driven baul in which pulverization takesplace as the coal passes through the sides of the rollers and the baul Aprimary air induced draught fan draws a stream of heated air through the
mill carrying the pulverized coal into a stationary classifier at the top of thepulverizer The classifier separates the pulverized coal from theunpulverized coalAdvantages of pulverized coal
bull Pulverized coal is used for large capacity plants
bull It is easier to adapt to fluctuating load as there are no limitationson the combustion capacity
bull Coal with higher ash percentage cannot be used with outpulverizing because of the problem of large amount ash deposition aftercombustion
bull
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bull Increased thermal efficiency is obtained through pulverization
bull The use of secondary air in the combustion chamber along withthe powered coal helps in creating
turbulence and therefore uniform mixing of the coal and the air duringcombustion
bull Greater surface area of coal per unit mass of coal allows fastercombustion as more coal is exposed to heat and combustion
bull The combustion process is almost free from clinker and slagformation
bull The boiler can be easily started from cold condition incase ofemergency
bull Practically no ash handling problem
bull The furnace volume required is less as the turbulence caused
aids in complete combustion of the coal with minimum travel of theparticlesThe pulverized coal is passed from the pulverizer to the boiler by means ofthe primary air that is used not only to dry the coal but also to heat is as itgoes into the boiler The secondary air is used to provide the necessary airrequired for complete combustion The primary air may vary anywherefrom 10 to the entire air depending on the design of the boiler The coalis sent into the boiler through burners A very important and widely usedtype of burner arrangement is the Tangential Firing arrangement
Tangential Burners
The tangential burners are arranged such that they discharge the fuel airmixture tangentially to an imaginary circle in the center of the furnace Theswirling action produces sufficient turbulence in the furnace to completethe combustion in a short period of time and avoid the necessity ofproducing high turbulence at the burner itself High heat release rates arepossible with this method of firing
The burners are placed at the four corners of the furnace At the ColumbiaPower Plant six sets of such burners are placed one above the other toform six firing zones These burners are constructed with tips that can
be angled through a small vertical arc By adjusting the angle of theburners the position of the fire ball can be adjusted so as to raise or lowerthe position of the turbulent combustion region When the burners are tilteddownward the furnace gets filled completely with the flame and the furnaceexit gas temperature gets reduced When the burners are tiled upward thefurnace exit gas temperature increases A difference of 100 degrees canbe achieved by tilting the burners
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5Ash Handling
The ever increasing capacities of boiler units together with their ability touse low grade high ash content coal have been responsible for thedevelopment of modern day ash handling systems The widely used ashhandling systems are
1 Mechanical Handling System2 Hydraulic System3 Pneumatic System4 Steam Jet SystemThe Hydraulic Ash handling system is used at the Columbia Power Plant
Hydraulic Ash Handling System
The hydraulic system carried the ash with the flow of water with high
velocity through a channel and finally dumps into a sump The hydraulicsystem is divided into a low velocity and high velocity system In the lowvelocity system the ash from the boilers fall into a stream of water flowinginto the sump The ash is carried along with the water and they areseparated at the sump In the high velocity system a jet of water is sprayedto quench the hot ash Two other jets force the ash into a trough in whichthey are washed away by the water into the sump where they areseparated The molten slag formed in the pulverized fuel system can alsobe quenched and washed by using the high velocity system Theadvantages of this system are that its clean large ash handling capacityconsiderable distance can be traversed absence of working parts incontact with ash
6High Pressure Boiler
It is a common practice to use high pressure and temperature boilers toincrease the efficiency of the plant and to decrease the cost of electricityproduction The boiler at the power plant is a water tube boiler whichmeans that water that is converted to steam is passed through the tubesinside the boiler The tubes are bent back and forth many times to ensurethat all the water is converted to steam Wet steam is not desirable when it
goes to the turbine as it may cause corrosion on the turbine blades A highpressure boiler is not a simple assemble of certain components likeburners super heaters air heaters and others The function of thecomponents is interrelated The location of the heat transfer surfaces isvery important and it depends on the required duty of the boiler and thequality of the coal used The most commonly used furnace layout orpulverized is shown in the figure In zone 1 heat transfer is primarily byradiation As the gases move upward and secondary air is added theeffect of radiation is reduced and convection becomes predominant Theheat transfer in Zone 2 and Zone 3 takes place mainly by convection
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Zones 2 being a high temperature zone and Zone 3 being the lowtemperature zone The evaporators are placed in the Zone 1 as it isdesirable to have lowest possible tube metal surface temperature becauseof AFT (ash fusion temperature) issues Since the Zone 2 has hightemperatures slagging is an important concern in this zone The excessheat is removed by using panels or platens which may either be superheaters or evaporators The Zone 3 because of comparatively lowtemperatures is ideally suited for heat recovery equipment likeeconomizers and air pre heaters
7 Boiler Accessories
A large amount of fuel is used in thermal power plant and very largeamount of heat is generated and carried by waste gases The loss wouldbe very high if the waste gases carry all the heat away The loss can hehalved by installing an economizer and a pre- heater in the path of thewaste gases The economizer transfers the heat from the waste gases tothe incoming feed water This reduces the heat required to convert thefeed water to steam The air pre heater increases the heat of the airsupplied into the boiler for combustion This increases the efficiency of theboiler
8 Economizer
The economizer is a feed water heater deriving heat from the flue gasesThe justifiable cost of the economizer depends on the total gain in
efficiency In turn this depends on the flue gas temperature leaving theboiler and the feed water inlet temperature A typical return bend typeeconomizer is shown in the figure
Types of economizerPlain Tube Economizer
These are generally used in case of boilers with natural draught The tubesare made of cast iron and their ends are pressed into top and bottomheaders The economizer is placed in the main flue gas path between theboiler and the chimney The waste flue gases flow outside the tubes and
heat is transferred to the water flowing inside High efficiency can beachieved by maintaining the water walls soot free
Grilled Tube Economizer
This is the type of economizer used in the power plant This type ofeconomizer reduced space considerably Rectangular grills are cast on thebare tube walls Economizer tubes may have finned tubes to increase theheat transfer rate Thicker fins offer greater efficiency than thinner onesbecause of greater surface area
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Air Pre-heater
The flue gases coming out of the economizer is used to preheat the airbefore supplying it to the combustion chamber An increase in airtemperature of 20 degrees can be achieved by this method The preheated air is used for combustion and also to dry the crushed coal beforepulverizing
Types of Air Heaters
Tubular Air HeaterThe flue gas flows outside the tubes in which the air flows heating it Toincrease the time of contact horizontal baffles are provided
Plate Type Air Heater
It consists of rectangular flat plates spaced 15 to 2 cm apart leavingalternate air and gas passages This is not used extensively as it involveshigh maintenance
Regenerative Air Heater
The transfer of heat from hot gas to cold air is done in 2 stages In the firststage the heat from the hot gases is passed to the packing of the airheater and the temperature of the gas is sufficiently reduced before lettingit out in the atmosphere This is called the heating period In the secondstage the heat from the packing is passed to the cold air This is called thecooling period
Soot Blowers
The fuel used in thermal power plants cause soot and this is deposited onthe boiler tubes economizer tubes air pre heaters etc This drasticallyreduces the amount of heat transfer of the heat exchangers Soot blowerscontrol the formation of soot and reduce its corrosive effects The types ofsoot blowers are fixed type which may be further classified into lane typeand mass type depending upon the type of spray and nozzle used Theother type of soot blower is the retractable soot blower The advantages
are that they are placed far away from the high temperature zone theyconcentrate the cleaning through a single large nozzle rather than manysmall nozzles and there is no concern of nozzle arrangement with respectto the boiler tubes
Condenser
The use of a condenser in a power plant is to improve the efficiency of thepower plant by decreasing the exhaust pressure of the steam belowatmosphere Another advantage of the condenser is that the steamcondensed may be recovered to provide a source of good pure feed water
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to the boiler an reduce the water softening capacity to a considerableextent A condenser is one of the essential components of a power plant
Types of Steam Condensers
Mixing or Jet Type Condenser These type of cndensers are mainly oftwo types Parallel flow type and Conunter flow type The parallel flow type
the steam and the water flow in the same direction and in the counter flowtype they flow in opposite directions These type are rarely used in highcapacity modern day power plants
Non Mixing Type or Surface Condensers In this type the cooling waterand steam do not come in contact with each other This is used wherelarge quantity of inferior quality water is available In this the cooling waterflows in pipes and the steam flows in a perpendicular direction to thepipes The velocity of water flowing is very high to absorb the heat from thesteam This condenser can be classified based on the number of passes
of the tube and the direction of the condensate flow and tube arrangementeither down flow or central flow
Cooling TowerThe importance of the cooling tower is felt when the cooling water from thecondenser has to be cooled The cooling water after condensing the steambecomes hot and it has to be cooled as it belongs to a closed system TheCooling towers do the job of decreasing the temperature of the coolingwater after condensing the steam in the condenser
The fan centered at the top of units draws air through two cells that arepaired to a suction chamber partitioned beneath the fan The outstandingfeature of this tower is lower air static pressure loss as there is lessresistance to air flow The evaporation and effective cooling of air isgreater when the air outside is warmer and dryer than when it is cold andalready saturated
Air Cooled Steam Condenser-
Air‐cooled steam condensers are increasingly employed to reject heat in
modern power plants
Air‐cooled condensers (ACCs) use ambient air to cool and condense a
process fluid Mechanical draft ACCs are used extensively in the chemicaland process industries and are finding increasing application in the globalelectric power producing industry due to economic and environmentalconsiderations
The generation of electric power is traditionally a water intensive activity
and with the sustainability of fresh water resources becoming a major
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concern in many parts of the world there is increasing pressure on thisindustry to find ways to reduce their fresh water consumption Modernthermoelectric power plants with steam turbines are equipped with acooling system to condense the turbine exhaust steam and maintain acertain turbine exhaust pressure (often referred to as turbinebackpressure) in a closed cycle )
Mechanical draft air‐
cooled steam condensers (ACSCs) consisting ofmultiple fan units are used in direct cooled thermoelectric power plantsto condense steam in a closed cycle using ambient air as the coolingmedium No water is directly consumed in the cooling process and assuch the total fresh water consumption of a power plant with an ACSC issignificantly less than one employing wet cooling There are a number ofadvantages over and above water consumption reduction such asincreased plant site flexibility and shortened licensing periodsassociated with the use of ACSCs
In a direct cooled steam turbine cycle with an ACSC low pressure steamis ducted from the turbine exhaust to steam headers that run along the
apex of a number of ACSC fan units (also referred to as A‐frame units or
cells) A typical forced draft ACSC fan unit consists of an axial flow fanlocated below a finned tube heat exchanger bundle The
steam condenses inside the finned tubes as a result of heat transfer toambient air forced through the heat exchanger by the fan The finned
tubes are typically arranged in an A‐ frame configuration for cooling
applications of this magnitude so as to maximize the available heat
transfer surface area while keeping the ACSC footprint to a minimumThe inclined tube configuration also aids in the effective drainage of thecondensate which is ultimately pumped back to the boiler or heat
recovery steam generator in the case of a combined‐cycle plant to
complete the closed cycle
Steam condensers coupled to the exhaust of these turbines returncondensate to the power cycle and boilerEither surface-type or air-cooled condensers can be selected The former have once-through orrecirculating water as the cooling medium while the latter are once-
through systems employing the atmosphere as the heat sink Amongthe advantages of air-cooled steam condensers compared with wetsystems are elimination of makeup water supply blowdown disposalwater-freezing problems water vapor plumes and concerns overgovernmental water-pollution restrictions Because of the dry nature ofthe equipment lowersystem-maintenance costs also result
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An air-cooled steam condenser system starts at the turbine exhaustflange It includes all of the equipment necessary to condense thesteam and return the condensate to the boiler feed water pipingThese items are
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1 Air-cooled steam condenser tower2 Air-flow control equipment3 Wind andor cell-partition walls4 Steam-bypass heating system5 Air removal equipment
6 Condensate storage tank7 Condensate pumps8 Steam ducts and expansion joints
9 Condensate drain and air-removal piping10 Instrumentation controls and alarms11 Pressure-relief device for protection of steam-turbine exhaustcasing12 Steam-duct condensate drain system
The basic air-cooled steam condenser includes the bundles steamdistribution manifold fans motors gear boxes and supporting steel Inlarge installations the cost of the tower structure supporting thecondenser bundles can be a substantial portion of the total cost Thestructures design specifications for wind load snow load live load andseismic requirements should be carefully chosen Generally grade-mounted towers cost less than roof-mounted ones
Limitations on plan dimensions must be made clear in the inquiryspecification Heat sources located close to the proposed tower and
discharging into the atmosphere must be identified The prevailingwind directions define the proper location and orientation of the towerwith respect to other large structures and heat sources Summer windsare important in the consideration of thermal performance and winterwinds in prescribing freeze-protection measures Noise limitationsshould also be stated since lower fan noise generally requires lowertip speed more fan blades and possibly wider blades
The purchaser should specify whether the thermal performanceguarantees are to be based on steam pressure measured at the
turbine exhaust flange or at the steam manifold inlet at thecondenser Other options are anall-welded system to reduce the potential for air leaks into the condenserand the use of extruded aluminum fins which provide longer trouble-freeoperation than embedded or wrap-on fins (these are prone to galvaniccorrosion because of their bimetallic tube-to-fin interface)
Airflow control equipment for freeze protection though an integral part ofthe engineered package supplied by the manufacturer nevertheless
reflects the purchasers preferences and needs Consideration should
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be given to variable-pitch fans air-flow control louvers steam isolatingvalves and two-speed motors The extra price of electric starters neededfor two-speed motors should be included
Wind walls are sometimes necessary to protect the bundles from windgusts that can upset equilibrium operating conditions and at times causefreezing in some remote parts of the tower Partition walls between fancells isolate operating cells from non operating ones Without partitionwalls a non operating fan would induce bypass of air intended for thebundles
Depending upon the minimum design ambient-air temperature the typeof turbine and the type of plant operation it may be economic to providea steam-bypass heating system for cold-weather startup This wouldoperate directly off the boiler requiring both a steam pressure-reducingstation and a de-superheating station with steam flow exhaustingdirectly into the main steam duct Part of the condenser heating steamduring startup would be supplied by the turbine exhaust and theremainder from this bypass system Alternatively large steam-isolatingvalves can be installed to supply condenser sections sequentially withsteam flows only from the turbine exhaust
The equipment extracting non condensables from the systemconsists of the hogging ejector and the operating ejectors Duringstartup the hogging ejector removes air from inside the turbinesteam ducts steam manifolds and bundles It reduces the airpressure within the system front atmospheric to about 10 in Hgabsolute in a time period
For the usual full-vacuum steam condenser a two-stage operatingejector system complete with condensers is normally provided with orwithout standby Its capacity is generally specified by the purchaser inaccord with the Heat Exchange Institute Standards for steam surfacecondensers Some purchasers add a safety allowance by doubling theventing capacity recommended in the standard Thc costliest parts of theejector package arc the inter- and after-condensers which are shell-and-tube construction These can be smaller and lower-cost if a separatecolder cooling-water supply is used instead of the hot condensate
Motor-operated vacuum pumps can also be chosen these adaptreadily to automated remote operations The purchasers inquiryspecification should establish for the air removal package thesepoints choice ofsteam-jet air ejector or motor-driven vacuum pump motive steampressure and temperature hogging-ejector minimum operating time evacuating capacity of operating ejectorpackage (compared with Standards recommendation) standby
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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2 Revised 0606
changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
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160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
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General Layout of Thermal Power Plant
The general layout of thermal power plant consists of mainly four circuitsas shown in [1] The four circuits are
1 Coal and Ash circuit2 Air and Gas circuit3 Feed Water and Steam circuit4 Cooling Water circuit
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1Coal and Ash Circuit
In this circuit the coal from the storage is fed to the boiler through coalhandling equipment for the generation of steam Ash produced due tocombustion of coal is removed to ash storage through ash-handlingsystem
2Air and Gas Circuit
Air is supplied to the combustion chamber of the boiler either throughforced draught or induced draught fan or by using both The dust from theair is removed before supplying to the combustion chamber The exhaustgases carrying sufficient quantity of heat and ash are passed through theair-heater where the exhaust heat of the gases is given to the air and thenit is passed through the dust collectors where most of the dust is removedbefore exhausting the gases to the atmosphere
3 Feed Water and Steam Circuit
The steam generated in the boiler is fed to the steam prime mover todevelop the power The steam coming out of the prime mover iscondensed in the condenser and then fed to the boiler with the help ofpump The condensate is heated in the feed-heaters using the steamtapped from different points of the turbine The feed
heaters may be of mixed type or indirect heating type Some of the steam
and water are lost passing through different components of the systemtherefore feed water is supplied from external source to compensate thisloss The feed water supplied from external source to compensate theloss The feed water supplied from external source is passed through thepurifying plant to reduce to reduce dissolve salts to an acceptable levelThis purification is necessary to avoid the scaling of the boiler tubes
4Cooling Water Circuit
The quantity of cooling water required to condense the steam isconsiderably high and it is taken from a lake river or sea At the Columbiathermal power plant it is taken from an artificial lake created near the plantThe water is pumped in by means of pumps and the hot water aftercondensing the steam is cooled before sending back into the pond bymeans of cooling towers This is done when there is not adequate naturalwater available close to the power plant This is a closed system where thewater goes to the pond and is re circulated back into the power plantGenerally open systems like rivers are more economical than closedsystems
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Working of the Thermal Power Plant
Steam is generated in the boiler of the thermal power plant using heat of
the fuel burnt in the combustion chamber The steam generated is passedthrough steam turbine where part of its thermal energy is converted intomechanical energy which is further used for generating electric power Thesteam coming out of the steam turbine is condensed in the condenser andthe condensate is supplied back to the boiler with the help of the feedpump and the cycle is repeated The function of the Boiler is to generatesteam The function of the condenser is to condense the steam coming outof the low pressure turbine The function of the steam turbine is to convertheat energy into mechanical energy The function of the condenser is toincrease the pressure of the condensate from the condenser pressure to
the boiler pressure The other components like economizer super heaterair heater and feed water heaters are used in the primary circuit toincrease the overall efficiency of the plant
Site Selection of a Thermal Power Plant
The important aspect to be borne in mind during site selection for athermal power plant are availability of coal ash disposal facility spacerequirement nature of land availability of water transport facility
availability of labor public problems size of the plant
The different types of systems and components used insteam power plant are as follows
(i ) High pressure boiler(ii ) Prime mover(iii ) Condenser (iv ) Coal handling system
(v ) Ash and dust handling system(vi ) Draught system(vii ) Feed water purification plant(viii ) Pumping system(ix ) Air pre heater economizer super heater feed heaters
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1CoalThe coal is obtained primarily from Wyoming This is done in most casesbut coal may also be shipped by trucks or by pipelines Inside the powerplant there is an unloading dock where the carts of the rail are heated tomelt the snow on the rail carts before unloading them The coal is stored inhuge heaps or piles of a half a mile in diameter The reason for stocking
this much of coal is because the loss due to loss of generation due to lackof coal is very high The upper layer of the coal heap has to be compactedto make it into a airtight surface to prevent loss of coal due to oxidationOther methods of preventing oxidation are by keeping it under water or byspraying chemicals on it
2 Coal handling In plant coal handling is a very important aspect of power plant
safety In variably the coal is not exposed as it can pollute the air andrelease poisonous gases like carbon monoxide The coal from the heaps ismoved into the plant by means of long conveyors that are electricallyoperated There are many different types of conveyors and coal-handlingdevices like screwing conveyors bucket elevators grabbing bucketconveyors etc
3 Coal CrusherBefore the coal is sent to the plant it has to be ensured that the coal is ofuniform size and so it is passed through coal crushers Also power plants
using pulverized coal specify a maximum coal size that can be fed into thepulverizer and so the coal has to be crushed to the specified size using thecoal crusher Rotary crushers are very commonly used for this purpose asthey can provide a continuous flow of coal to the pulverizer
4PulverizerMost commonly used pulverizer is the Boul Mill The arrangement consistsof 2 stationary rollers and a power driven baul in which pulverization takesplace as the coal passes through the sides of the rollers and the baul Aprimary air induced draught fan draws a stream of heated air through the
mill carrying the pulverized coal into a stationary classifier at the top of thepulverizer The classifier separates the pulverized coal from theunpulverized coalAdvantages of pulverized coal
bull Pulverized coal is used for large capacity plants
bull It is easier to adapt to fluctuating load as there are no limitationson the combustion capacity
bull Coal with higher ash percentage cannot be used with outpulverizing because of the problem of large amount ash deposition aftercombustion
bull
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bull Increased thermal efficiency is obtained through pulverization
bull The use of secondary air in the combustion chamber along withthe powered coal helps in creating
turbulence and therefore uniform mixing of the coal and the air duringcombustion
bull Greater surface area of coal per unit mass of coal allows fastercombustion as more coal is exposed to heat and combustion
bull The combustion process is almost free from clinker and slagformation
bull The boiler can be easily started from cold condition incase ofemergency
bull Practically no ash handling problem
bull The furnace volume required is less as the turbulence caused
aids in complete combustion of the coal with minimum travel of theparticlesThe pulverized coal is passed from the pulverizer to the boiler by means ofthe primary air that is used not only to dry the coal but also to heat is as itgoes into the boiler The secondary air is used to provide the necessary airrequired for complete combustion The primary air may vary anywherefrom 10 to the entire air depending on the design of the boiler The coalis sent into the boiler through burners A very important and widely usedtype of burner arrangement is the Tangential Firing arrangement
Tangential Burners
The tangential burners are arranged such that they discharge the fuel airmixture tangentially to an imaginary circle in the center of the furnace Theswirling action produces sufficient turbulence in the furnace to completethe combustion in a short period of time and avoid the necessity ofproducing high turbulence at the burner itself High heat release rates arepossible with this method of firing
The burners are placed at the four corners of the furnace At the ColumbiaPower Plant six sets of such burners are placed one above the other toform six firing zones These burners are constructed with tips that can
be angled through a small vertical arc By adjusting the angle of theburners the position of the fire ball can be adjusted so as to raise or lowerthe position of the turbulent combustion region When the burners are tilteddownward the furnace gets filled completely with the flame and the furnaceexit gas temperature gets reduced When the burners are tiled upward thefurnace exit gas temperature increases A difference of 100 degrees canbe achieved by tilting the burners
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5Ash Handling
The ever increasing capacities of boiler units together with their ability touse low grade high ash content coal have been responsible for thedevelopment of modern day ash handling systems The widely used ashhandling systems are
1 Mechanical Handling System2 Hydraulic System3 Pneumatic System4 Steam Jet SystemThe Hydraulic Ash handling system is used at the Columbia Power Plant
Hydraulic Ash Handling System
The hydraulic system carried the ash with the flow of water with high
velocity through a channel and finally dumps into a sump The hydraulicsystem is divided into a low velocity and high velocity system In the lowvelocity system the ash from the boilers fall into a stream of water flowinginto the sump The ash is carried along with the water and they areseparated at the sump In the high velocity system a jet of water is sprayedto quench the hot ash Two other jets force the ash into a trough in whichthey are washed away by the water into the sump where they areseparated The molten slag formed in the pulverized fuel system can alsobe quenched and washed by using the high velocity system Theadvantages of this system are that its clean large ash handling capacityconsiderable distance can be traversed absence of working parts incontact with ash
6High Pressure Boiler
It is a common practice to use high pressure and temperature boilers toincrease the efficiency of the plant and to decrease the cost of electricityproduction The boiler at the power plant is a water tube boiler whichmeans that water that is converted to steam is passed through the tubesinside the boiler The tubes are bent back and forth many times to ensurethat all the water is converted to steam Wet steam is not desirable when it
goes to the turbine as it may cause corrosion on the turbine blades A highpressure boiler is not a simple assemble of certain components likeburners super heaters air heaters and others The function of thecomponents is interrelated The location of the heat transfer surfaces isvery important and it depends on the required duty of the boiler and thequality of the coal used The most commonly used furnace layout orpulverized is shown in the figure In zone 1 heat transfer is primarily byradiation As the gases move upward and secondary air is added theeffect of radiation is reduced and convection becomes predominant Theheat transfer in Zone 2 and Zone 3 takes place mainly by convection
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Zones 2 being a high temperature zone and Zone 3 being the lowtemperature zone The evaporators are placed in the Zone 1 as it isdesirable to have lowest possible tube metal surface temperature becauseof AFT (ash fusion temperature) issues Since the Zone 2 has hightemperatures slagging is an important concern in this zone The excessheat is removed by using panels or platens which may either be superheaters or evaporators The Zone 3 because of comparatively lowtemperatures is ideally suited for heat recovery equipment likeeconomizers and air pre heaters
7 Boiler Accessories
A large amount of fuel is used in thermal power plant and very largeamount of heat is generated and carried by waste gases The loss wouldbe very high if the waste gases carry all the heat away The loss can hehalved by installing an economizer and a pre- heater in the path of thewaste gases The economizer transfers the heat from the waste gases tothe incoming feed water This reduces the heat required to convert thefeed water to steam The air pre heater increases the heat of the airsupplied into the boiler for combustion This increases the efficiency of theboiler
8 Economizer
The economizer is a feed water heater deriving heat from the flue gasesThe justifiable cost of the economizer depends on the total gain in
efficiency In turn this depends on the flue gas temperature leaving theboiler and the feed water inlet temperature A typical return bend typeeconomizer is shown in the figure
Types of economizerPlain Tube Economizer
These are generally used in case of boilers with natural draught The tubesare made of cast iron and their ends are pressed into top and bottomheaders The economizer is placed in the main flue gas path between theboiler and the chimney The waste flue gases flow outside the tubes and
heat is transferred to the water flowing inside High efficiency can beachieved by maintaining the water walls soot free
Grilled Tube Economizer
This is the type of economizer used in the power plant This type ofeconomizer reduced space considerably Rectangular grills are cast on thebare tube walls Economizer tubes may have finned tubes to increase theheat transfer rate Thicker fins offer greater efficiency than thinner onesbecause of greater surface area
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Air Pre-heater
The flue gases coming out of the economizer is used to preheat the airbefore supplying it to the combustion chamber An increase in airtemperature of 20 degrees can be achieved by this method The preheated air is used for combustion and also to dry the crushed coal beforepulverizing
Types of Air Heaters
Tubular Air HeaterThe flue gas flows outside the tubes in which the air flows heating it Toincrease the time of contact horizontal baffles are provided
Plate Type Air Heater
It consists of rectangular flat plates spaced 15 to 2 cm apart leavingalternate air and gas passages This is not used extensively as it involveshigh maintenance
Regenerative Air Heater
The transfer of heat from hot gas to cold air is done in 2 stages In the firststage the heat from the hot gases is passed to the packing of the airheater and the temperature of the gas is sufficiently reduced before lettingit out in the atmosphere This is called the heating period In the secondstage the heat from the packing is passed to the cold air This is called thecooling period
Soot Blowers
The fuel used in thermal power plants cause soot and this is deposited onthe boiler tubes economizer tubes air pre heaters etc This drasticallyreduces the amount of heat transfer of the heat exchangers Soot blowerscontrol the formation of soot and reduce its corrosive effects The types ofsoot blowers are fixed type which may be further classified into lane typeand mass type depending upon the type of spray and nozzle used Theother type of soot blower is the retractable soot blower The advantages
are that they are placed far away from the high temperature zone theyconcentrate the cleaning through a single large nozzle rather than manysmall nozzles and there is no concern of nozzle arrangement with respectto the boiler tubes
Condenser
The use of a condenser in a power plant is to improve the efficiency of thepower plant by decreasing the exhaust pressure of the steam belowatmosphere Another advantage of the condenser is that the steamcondensed may be recovered to provide a source of good pure feed water
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to the boiler an reduce the water softening capacity to a considerableextent A condenser is one of the essential components of a power plant
Types of Steam Condensers
Mixing or Jet Type Condenser These type of cndensers are mainly oftwo types Parallel flow type and Conunter flow type The parallel flow type
the steam and the water flow in the same direction and in the counter flowtype they flow in opposite directions These type are rarely used in highcapacity modern day power plants
Non Mixing Type or Surface Condensers In this type the cooling waterand steam do not come in contact with each other This is used wherelarge quantity of inferior quality water is available In this the cooling waterflows in pipes and the steam flows in a perpendicular direction to thepipes The velocity of water flowing is very high to absorb the heat from thesteam This condenser can be classified based on the number of passes
of the tube and the direction of the condensate flow and tube arrangementeither down flow or central flow
Cooling TowerThe importance of the cooling tower is felt when the cooling water from thecondenser has to be cooled The cooling water after condensing the steambecomes hot and it has to be cooled as it belongs to a closed system TheCooling towers do the job of decreasing the temperature of the coolingwater after condensing the steam in the condenser
The fan centered at the top of units draws air through two cells that arepaired to a suction chamber partitioned beneath the fan The outstandingfeature of this tower is lower air static pressure loss as there is lessresistance to air flow The evaporation and effective cooling of air isgreater when the air outside is warmer and dryer than when it is cold andalready saturated
Air Cooled Steam Condenser-
Air‐cooled steam condensers are increasingly employed to reject heat in
modern power plants
Air‐cooled condensers (ACCs) use ambient air to cool and condense a
process fluid Mechanical draft ACCs are used extensively in the chemicaland process industries and are finding increasing application in the globalelectric power producing industry due to economic and environmentalconsiderations
The generation of electric power is traditionally a water intensive activity
and with the sustainability of fresh water resources becoming a major
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concern in many parts of the world there is increasing pressure on thisindustry to find ways to reduce their fresh water consumption Modernthermoelectric power plants with steam turbines are equipped with acooling system to condense the turbine exhaust steam and maintain acertain turbine exhaust pressure (often referred to as turbinebackpressure) in a closed cycle )
Mechanical draft air‐
cooled steam condensers (ACSCs) consisting ofmultiple fan units are used in direct cooled thermoelectric power plantsto condense steam in a closed cycle using ambient air as the coolingmedium No water is directly consumed in the cooling process and assuch the total fresh water consumption of a power plant with an ACSC issignificantly less than one employing wet cooling There are a number ofadvantages over and above water consumption reduction such asincreased plant site flexibility and shortened licensing periodsassociated with the use of ACSCs
In a direct cooled steam turbine cycle with an ACSC low pressure steamis ducted from the turbine exhaust to steam headers that run along the
apex of a number of ACSC fan units (also referred to as A‐frame units or
cells) A typical forced draft ACSC fan unit consists of an axial flow fanlocated below a finned tube heat exchanger bundle The
steam condenses inside the finned tubes as a result of heat transfer toambient air forced through the heat exchanger by the fan The finned
tubes are typically arranged in an A‐ frame configuration for cooling
applications of this magnitude so as to maximize the available heat
transfer surface area while keeping the ACSC footprint to a minimumThe inclined tube configuration also aids in the effective drainage of thecondensate which is ultimately pumped back to the boiler or heat
recovery steam generator in the case of a combined‐cycle plant to
complete the closed cycle
Steam condensers coupled to the exhaust of these turbines returncondensate to the power cycle and boilerEither surface-type or air-cooled condensers can be selected The former have once-through orrecirculating water as the cooling medium while the latter are once-
through systems employing the atmosphere as the heat sink Amongthe advantages of air-cooled steam condensers compared with wetsystems are elimination of makeup water supply blowdown disposalwater-freezing problems water vapor plumes and concerns overgovernmental water-pollution restrictions Because of the dry nature ofthe equipment lowersystem-maintenance costs also result
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An air-cooled steam condenser system starts at the turbine exhaustflange It includes all of the equipment necessary to condense thesteam and return the condensate to the boiler feed water pipingThese items are
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1 Air-cooled steam condenser tower2 Air-flow control equipment3 Wind andor cell-partition walls4 Steam-bypass heating system5 Air removal equipment
6 Condensate storage tank7 Condensate pumps8 Steam ducts and expansion joints
9 Condensate drain and air-removal piping10 Instrumentation controls and alarms11 Pressure-relief device for protection of steam-turbine exhaustcasing12 Steam-duct condensate drain system
The basic air-cooled steam condenser includes the bundles steamdistribution manifold fans motors gear boxes and supporting steel Inlarge installations the cost of the tower structure supporting thecondenser bundles can be a substantial portion of the total cost Thestructures design specifications for wind load snow load live load andseismic requirements should be carefully chosen Generally grade-mounted towers cost less than roof-mounted ones
Limitations on plan dimensions must be made clear in the inquiryspecification Heat sources located close to the proposed tower and
discharging into the atmosphere must be identified The prevailingwind directions define the proper location and orientation of the towerwith respect to other large structures and heat sources Summer windsare important in the consideration of thermal performance and winterwinds in prescribing freeze-protection measures Noise limitationsshould also be stated since lower fan noise generally requires lowertip speed more fan blades and possibly wider blades
The purchaser should specify whether the thermal performanceguarantees are to be based on steam pressure measured at the
turbine exhaust flange or at the steam manifold inlet at thecondenser Other options are anall-welded system to reduce the potential for air leaks into the condenserand the use of extruded aluminum fins which provide longer trouble-freeoperation than embedded or wrap-on fins (these are prone to galvaniccorrosion because of their bimetallic tube-to-fin interface)
Airflow control equipment for freeze protection though an integral part ofthe engineered package supplied by the manufacturer nevertheless
reflects the purchasers preferences and needs Consideration should
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be given to variable-pitch fans air-flow control louvers steam isolatingvalves and two-speed motors The extra price of electric starters neededfor two-speed motors should be included
Wind walls are sometimes necessary to protect the bundles from windgusts that can upset equilibrium operating conditions and at times causefreezing in some remote parts of the tower Partition walls between fancells isolate operating cells from non operating ones Without partitionwalls a non operating fan would induce bypass of air intended for thebundles
Depending upon the minimum design ambient-air temperature the typeof turbine and the type of plant operation it may be economic to providea steam-bypass heating system for cold-weather startup This wouldoperate directly off the boiler requiring both a steam pressure-reducingstation and a de-superheating station with steam flow exhaustingdirectly into the main steam duct Part of the condenser heating steamduring startup would be supplied by the turbine exhaust and theremainder from this bypass system Alternatively large steam-isolatingvalves can be installed to supply condenser sections sequentially withsteam flows only from the turbine exhaust
The equipment extracting non condensables from the systemconsists of the hogging ejector and the operating ejectors Duringstartup the hogging ejector removes air from inside the turbinesteam ducts steam manifolds and bundles It reduces the airpressure within the system front atmospheric to about 10 in Hgabsolute in a time period
For the usual full-vacuum steam condenser a two-stage operatingejector system complete with condensers is normally provided with orwithout standby Its capacity is generally specified by the purchaser inaccord with the Heat Exchange Institute Standards for steam surfacecondensers Some purchasers add a safety allowance by doubling theventing capacity recommended in the standard Thc costliest parts of theejector package arc the inter- and after-condensers which are shell-and-tube construction These can be smaller and lower-cost if a separatecolder cooling-water supply is used instead of the hot condensate
Motor-operated vacuum pumps can also be chosen these adaptreadily to automated remote operations The purchasers inquiryspecification should establish for the air removal package thesepoints choice ofsteam-jet air ejector or motor-driven vacuum pump motive steampressure and temperature hogging-ejector minimum operating time evacuating capacity of operating ejectorpackage (compared with Standards recommendation) standby
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
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160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
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1Coal and Ash Circuit
In this circuit the coal from the storage is fed to the boiler through coalhandling equipment for the generation of steam Ash produced due tocombustion of coal is removed to ash storage through ash-handlingsystem
2Air and Gas Circuit
Air is supplied to the combustion chamber of the boiler either throughforced draught or induced draught fan or by using both The dust from theair is removed before supplying to the combustion chamber The exhaustgases carrying sufficient quantity of heat and ash are passed through theair-heater where the exhaust heat of the gases is given to the air and thenit is passed through the dust collectors where most of the dust is removedbefore exhausting the gases to the atmosphere
3 Feed Water and Steam Circuit
The steam generated in the boiler is fed to the steam prime mover todevelop the power The steam coming out of the prime mover iscondensed in the condenser and then fed to the boiler with the help ofpump The condensate is heated in the feed-heaters using the steamtapped from different points of the turbine The feed
heaters may be of mixed type or indirect heating type Some of the steam
and water are lost passing through different components of the systemtherefore feed water is supplied from external source to compensate thisloss The feed water supplied from external source to compensate theloss The feed water supplied from external source is passed through thepurifying plant to reduce to reduce dissolve salts to an acceptable levelThis purification is necessary to avoid the scaling of the boiler tubes
4Cooling Water Circuit
The quantity of cooling water required to condense the steam isconsiderably high and it is taken from a lake river or sea At the Columbiathermal power plant it is taken from an artificial lake created near the plantThe water is pumped in by means of pumps and the hot water aftercondensing the steam is cooled before sending back into the pond bymeans of cooling towers This is done when there is not adequate naturalwater available close to the power plant This is a closed system where thewater goes to the pond and is re circulated back into the power plantGenerally open systems like rivers are more economical than closedsystems
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Working of the Thermal Power Plant
Steam is generated in the boiler of the thermal power plant using heat of
the fuel burnt in the combustion chamber The steam generated is passedthrough steam turbine where part of its thermal energy is converted intomechanical energy which is further used for generating electric power Thesteam coming out of the steam turbine is condensed in the condenser andthe condensate is supplied back to the boiler with the help of the feedpump and the cycle is repeated The function of the Boiler is to generatesteam The function of the condenser is to condense the steam coming outof the low pressure turbine The function of the steam turbine is to convertheat energy into mechanical energy The function of the condenser is toincrease the pressure of the condensate from the condenser pressure to
the boiler pressure The other components like economizer super heaterair heater and feed water heaters are used in the primary circuit toincrease the overall efficiency of the plant
Site Selection of a Thermal Power Plant
The important aspect to be borne in mind during site selection for athermal power plant are availability of coal ash disposal facility spacerequirement nature of land availability of water transport facility
availability of labor public problems size of the plant
The different types of systems and components used insteam power plant are as follows
(i ) High pressure boiler(ii ) Prime mover(iii ) Condenser (iv ) Coal handling system
(v ) Ash and dust handling system(vi ) Draught system(vii ) Feed water purification plant(viii ) Pumping system(ix ) Air pre heater economizer super heater feed heaters
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1CoalThe coal is obtained primarily from Wyoming This is done in most casesbut coal may also be shipped by trucks or by pipelines Inside the powerplant there is an unloading dock where the carts of the rail are heated tomelt the snow on the rail carts before unloading them The coal is stored inhuge heaps or piles of a half a mile in diameter The reason for stocking
this much of coal is because the loss due to loss of generation due to lackof coal is very high The upper layer of the coal heap has to be compactedto make it into a airtight surface to prevent loss of coal due to oxidationOther methods of preventing oxidation are by keeping it under water or byspraying chemicals on it
2 Coal handling In plant coal handling is a very important aspect of power plant
safety In variably the coal is not exposed as it can pollute the air andrelease poisonous gases like carbon monoxide The coal from the heaps ismoved into the plant by means of long conveyors that are electricallyoperated There are many different types of conveyors and coal-handlingdevices like screwing conveyors bucket elevators grabbing bucketconveyors etc
3 Coal CrusherBefore the coal is sent to the plant it has to be ensured that the coal is ofuniform size and so it is passed through coal crushers Also power plants
using pulverized coal specify a maximum coal size that can be fed into thepulverizer and so the coal has to be crushed to the specified size using thecoal crusher Rotary crushers are very commonly used for this purpose asthey can provide a continuous flow of coal to the pulverizer
4PulverizerMost commonly used pulverizer is the Boul Mill The arrangement consistsof 2 stationary rollers and a power driven baul in which pulverization takesplace as the coal passes through the sides of the rollers and the baul Aprimary air induced draught fan draws a stream of heated air through the
mill carrying the pulverized coal into a stationary classifier at the top of thepulverizer The classifier separates the pulverized coal from theunpulverized coalAdvantages of pulverized coal
bull Pulverized coal is used for large capacity plants
bull It is easier to adapt to fluctuating load as there are no limitationson the combustion capacity
bull Coal with higher ash percentage cannot be used with outpulverizing because of the problem of large amount ash deposition aftercombustion
bull
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bull Increased thermal efficiency is obtained through pulverization
bull The use of secondary air in the combustion chamber along withthe powered coal helps in creating
turbulence and therefore uniform mixing of the coal and the air duringcombustion
bull Greater surface area of coal per unit mass of coal allows fastercombustion as more coal is exposed to heat and combustion
bull The combustion process is almost free from clinker and slagformation
bull The boiler can be easily started from cold condition incase ofemergency
bull Practically no ash handling problem
bull The furnace volume required is less as the turbulence caused
aids in complete combustion of the coal with minimum travel of theparticlesThe pulverized coal is passed from the pulverizer to the boiler by means ofthe primary air that is used not only to dry the coal but also to heat is as itgoes into the boiler The secondary air is used to provide the necessary airrequired for complete combustion The primary air may vary anywherefrom 10 to the entire air depending on the design of the boiler The coalis sent into the boiler through burners A very important and widely usedtype of burner arrangement is the Tangential Firing arrangement
Tangential Burners
The tangential burners are arranged such that they discharge the fuel airmixture tangentially to an imaginary circle in the center of the furnace Theswirling action produces sufficient turbulence in the furnace to completethe combustion in a short period of time and avoid the necessity ofproducing high turbulence at the burner itself High heat release rates arepossible with this method of firing
The burners are placed at the four corners of the furnace At the ColumbiaPower Plant six sets of such burners are placed one above the other toform six firing zones These burners are constructed with tips that can
be angled through a small vertical arc By adjusting the angle of theburners the position of the fire ball can be adjusted so as to raise or lowerthe position of the turbulent combustion region When the burners are tilteddownward the furnace gets filled completely with the flame and the furnaceexit gas temperature gets reduced When the burners are tiled upward thefurnace exit gas temperature increases A difference of 100 degrees canbe achieved by tilting the burners
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5Ash Handling
The ever increasing capacities of boiler units together with their ability touse low grade high ash content coal have been responsible for thedevelopment of modern day ash handling systems The widely used ashhandling systems are
1 Mechanical Handling System2 Hydraulic System3 Pneumatic System4 Steam Jet SystemThe Hydraulic Ash handling system is used at the Columbia Power Plant
Hydraulic Ash Handling System
The hydraulic system carried the ash with the flow of water with high
velocity through a channel and finally dumps into a sump The hydraulicsystem is divided into a low velocity and high velocity system In the lowvelocity system the ash from the boilers fall into a stream of water flowinginto the sump The ash is carried along with the water and they areseparated at the sump In the high velocity system a jet of water is sprayedto quench the hot ash Two other jets force the ash into a trough in whichthey are washed away by the water into the sump where they areseparated The molten slag formed in the pulverized fuel system can alsobe quenched and washed by using the high velocity system Theadvantages of this system are that its clean large ash handling capacityconsiderable distance can be traversed absence of working parts incontact with ash
6High Pressure Boiler
It is a common practice to use high pressure and temperature boilers toincrease the efficiency of the plant and to decrease the cost of electricityproduction The boiler at the power plant is a water tube boiler whichmeans that water that is converted to steam is passed through the tubesinside the boiler The tubes are bent back and forth many times to ensurethat all the water is converted to steam Wet steam is not desirable when it
goes to the turbine as it may cause corrosion on the turbine blades A highpressure boiler is not a simple assemble of certain components likeburners super heaters air heaters and others The function of thecomponents is interrelated The location of the heat transfer surfaces isvery important and it depends on the required duty of the boiler and thequality of the coal used The most commonly used furnace layout orpulverized is shown in the figure In zone 1 heat transfer is primarily byradiation As the gases move upward and secondary air is added theeffect of radiation is reduced and convection becomes predominant Theheat transfer in Zone 2 and Zone 3 takes place mainly by convection
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Zones 2 being a high temperature zone and Zone 3 being the lowtemperature zone The evaporators are placed in the Zone 1 as it isdesirable to have lowest possible tube metal surface temperature becauseof AFT (ash fusion temperature) issues Since the Zone 2 has hightemperatures slagging is an important concern in this zone The excessheat is removed by using panels or platens which may either be superheaters or evaporators The Zone 3 because of comparatively lowtemperatures is ideally suited for heat recovery equipment likeeconomizers and air pre heaters
7 Boiler Accessories
A large amount of fuel is used in thermal power plant and very largeamount of heat is generated and carried by waste gases The loss wouldbe very high if the waste gases carry all the heat away The loss can hehalved by installing an economizer and a pre- heater in the path of thewaste gases The economizer transfers the heat from the waste gases tothe incoming feed water This reduces the heat required to convert thefeed water to steam The air pre heater increases the heat of the airsupplied into the boiler for combustion This increases the efficiency of theboiler
8 Economizer
The economizer is a feed water heater deriving heat from the flue gasesThe justifiable cost of the economizer depends on the total gain in
efficiency In turn this depends on the flue gas temperature leaving theboiler and the feed water inlet temperature A typical return bend typeeconomizer is shown in the figure
Types of economizerPlain Tube Economizer
These are generally used in case of boilers with natural draught The tubesare made of cast iron and their ends are pressed into top and bottomheaders The economizer is placed in the main flue gas path between theboiler and the chimney The waste flue gases flow outside the tubes and
heat is transferred to the water flowing inside High efficiency can beachieved by maintaining the water walls soot free
Grilled Tube Economizer
This is the type of economizer used in the power plant This type ofeconomizer reduced space considerably Rectangular grills are cast on thebare tube walls Economizer tubes may have finned tubes to increase theheat transfer rate Thicker fins offer greater efficiency than thinner onesbecause of greater surface area
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Air Pre-heater
The flue gases coming out of the economizer is used to preheat the airbefore supplying it to the combustion chamber An increase in airtemperature of 20 degrees can be achieved by this method The preheated air is used for combustion and also to dry the crushed coal beforepulverizing
Types of Air Heaters
Tubular Air HeaterThe flue gas flows outside the tubes in which the air flows heating it Toincrease the time of contact horizontal baffles are provided
Plate Type Air Heater
It consists of rectangular flat plates spaced 15 to 2 cm apart leavingalternate air and gas passages This is not used extensively as it involveshigh maintenance
Regenerative Air Heater
The transfer of heat from hot gas to cold air is done in 2 stages In the firststage the heat from the hot gases is passed to the packing of the airheater and the temperature of the gas is sufficiently reduced before lettingit out in the atmosphere This is called the heating period In the secondstage the heat from the packing is passed to the cold air This is called thecooling period
Soot Blowers
The fuel used in thermal power plants cause soot and this is deposited onthe boiler tubes economizer tubes air pre heaters etc This drasticallyreduces the amount of heat transfer of the heat exchangers Soot blowerscontrol the formation of soot and reduce its corrosive effects The types ofsoot blowers are fixed type which may be further classified into lane typeand mass type depending upon the type of spray and nozzle used Theother type of soot blower is the retractable soot blower The advantages
are that they are placed far away from the high temperature zone theyconcentrate the cleaning through a single large nozzle rather than manysmall nozzles and there is no concern of nozzle arrangement with respectto the boiler tubes
Condenser
The use of a condenser in a power plant is to improve the efficiency of thepower plant by decreasing the exhaust pressure of the steam belowatmosphere Another advantage of the condenser is that the steamcondensed may be recovered to provide a source of good pure feed water
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to the boiler an reduce the water softening capacity to a considerableextent A condenser is one of the essential components of a power plant
Types of Steam Condensers
Mixing or Jet Type Condenser These type of cndensers are mainly oftwo types Parallel flow type and Conunter flow type The parallel flow type
the steam and the water flow in the same direction and in the counter flowtype they flow in opposite directions These type are rarely used in highcapacity modern day power plants
Non Mixing Type or Surface Condensers In this type the cooling waterand steam do not come in contact with each other This is used wherelarge quantity of inferior quality water is available In this the cooling waterflows in pipes and the steam flows in a perpendicular direction to thepipes The velocity of water flowing is very high to absorb the heat from thesteam This condenser can be classified based on the number of passes
of the tube and the direction of the condensate flow and tube arrangementeither down flow or central flow
Cooling TowerThe importance of the cooling tower is felt when the cooling water from thecondenser has to be cooled The cooling water after condensing the steambecomes hot and it has to be cooled as it belongs to a closed system TheCooling towers do the job of decreasing the temperature of the coolingwater after condensing the steam in the condenser
The fan centered at the top of units draws air through two cells that arepaired to a suction chamber partitioned beneath the fan The outstandingfeature of this tower is lower air static pressure loss as there is lessresistance to air flow The evaporation and effective cooling of air isgreater when the air outside is warmer and dryer than when it is cold andalready saturated
Air Cooled Steam Condenser-
Air‐cooled steam condensers are increasingly employed to reject heat in
modern power plants
Air‐cooled condensers (ACCs) use ambient air to cool and condense a
process fluid Mechanical draft ACCs are used extensively in the chemicaland process industries and are finding increasing application in the globalelectric power producing industry due to economic and environmentalconsiderations
The generation of electric power is traditionally a water intensive activity
and with the sustainability of fresh water resources becoming a major
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concern in many parts of the world there is increasing pressure on thisindustry to find ways to reduce their fresh water consumption Modernthermoelectric power plants with steam turbines are equipped with acooling system to condense the turbine exhaust steam and maintain acertain turbine exhaust pressure (often referred to as turbinebackpressure) in a closed cycle )
Mechanical draft air‐
cooled steam condensers (ACSCs) consisting ofmultiple fan units are used in direct cooled thermoelectric power plantsto condense steam in a closed cycle using ambient air as the coolingmedium No water is directly consumed in the cooling process and assuch the total fresh water consumption of a power plant with an ACSC issignificantly less than one employing wet cooling There are a number ofadvantages over and above water consumption reduction such asincreased plant site flexibility and shortened licensing periodsassociated with the use of ACSCs
In a direct cooled steam turbine cycle with an ACSC low pressure steamis ducted from the turbine exhaust to steam headers that run along the
apex of a number of ACSC fan units (also referred to as A‐frame units or
cells) A typical forced draft ACSC fan unit consists of an axial flow fanlocated below a finned tube heat exchanger bundle The
steam condenses inside the finned tubes as a result of heat transfer toambient air forced through the heat exchanger by the fan The finned
tubes are typically arranged in an A‐ frame configuration for cooling
applications of this magnitude so as to maximize the available heat
transfer surface area while keeping the ACSC footprint to a minimumThe inclined tube configuration also aids in the effective drainage of thecondensate which is ultimately pumped back to the boiler or heat
recovery steam generator in the case of a combined‐cycle plant to
complete the closed cycle
Steam condensers coupled to the exhaust of these turbines returncondensate to the power cycle and boilerEither surface-type or air-cooled condensers can be selected The former have once-through orrecirculating water as the cooling medium while the latter are once-
through systems employing the atmosphere as the heat sink Amongthe advantages of air-cooled steam condensers compared with wetsystems are elimination of makeup water supply blowdown disposalwater-freezing problems water vapor plumes and concerns overgovernmental water-pollution restrictions Because of the dry nature ofthe equipment lowersystem-maintenance costs also result
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An air-cooled steam condenser system starts at the turbine exhaustflange It includes all of the equipment necessary to condense thesteam and return the condensate to the boiler feed water pipingThese items are
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1 Air-cooled steam condenser tower2 Air-flow control equipment3 Wind andor cell-partition walls4 Steam-bypass heating system5 Air removal equipment
6 Condensate storage tank7 Condensate pumps8 Steam ducts and expansion joints
9 Condensate drain and air-removal piping10 Instrumentation controls and alarms11 Pressure-relief device for protection of steam-turbine exhaustcasing12 Steam-duct condensate drain system
The basic air-cooled steam condenser includes the bundles steamdistribution manifold fans motors gear boxes and supporting steel Inlarge installations the cost of the tower structure supporting thecondenser bundles can be a substantial portion of the total cost Thestructures design specifications for wind load snow load live load andseismic requirements should be carefully chosen Generally grade-mounted towers cost less than roof-mounted ones
Limitations on plan dimensions must be made clear in the inquiryspecification Heat sources located close to the proposed tower and
discharging into the atmosphere must be identified The prevailingwind directions define the proper location and orientation of the towerwith respect to other large structures and heat sources Summer windsare important in the consideration of thermal performance and winterwinds in prescribing freeze-protection measures Noise limitationsshould also be stated since lower fan noise generally requires lowertip speed more fan blades and possibly wider blades
The purchaser should specify whether the thermal performanceguarantees are to be based on steam pressure measured at the
turbine exhaust flange or at the steam manifold inlet at thecondenser Other options are anall-welded system to reduce the potential for air leaks into the condenserand the use of extruded aluminum fins which provide longer trouble-freeoperation than embedded or wrap-on fins (these are prone to galvaniccorrosion because of their bimetallic tube-to-fin interface)
Airflow control equipment for freeze protection though an integral part ofthe engineered package supplied by the manufacturer nevertheless
reflects the purchasers preferences and needs Consideration should
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be given to variable-pitch fans air-flow control louvers steam isolatingvalves and two-speed motors The extra price of electric starters neededfor two-speed motors should be included
Wind walls are sometimes necessary to protect the bundles from windgusts that can upset equilibrium operating conditions and at times causefreezing in some remote parts of the tower Partition walls between fancells isolate operating cells from non operating ones Without partitionwalls a non operating fan would induce bypass of air intended for thebundles
Depending upon the minimum design ambient-air temperature the typeof turbine and the type of plant operation it may be economic to providea steam-bypass heating system for cold-weather startup This wouldoperate directly off the boiler requiring both a steam pressure-reducingstation and a de-superheating station with steam flow exhaustingdirectly into the main steam duct Part of the condenser heating steamduring startup would be supplied by the turbine exhaust and theremainder from this bypass system Alternatively large steam-isolatingvalves can be installed to supply condenser sections sequentially withsteam flows only from the turbine exhaust
The equipment extracting non condensables from the systemconsists of the hogging ejector and the operating ejectors Duringstartup the hogging ejector removes air from inside the turbinesteam ducts steam manifolds and bundles It reduces the airpressure within the system front atmospheric to about 10 in Hgabsolute in a time period
For the usual full-vacuum steam condenser a two-stage operatingejector system complete with condensers is normally provided with orwithout standby Its capacity is generally specified by the purchaser inaccord with the Heat Exchange Institute Standards for steam surfacecondensers Some purchasers add a safety allowance by doubling theventing capacity recommended in the standard Thc costliest parts of theejector package arc the inter- and after-condensers which are shell-and-tube construction These can be smaller and lower-cost if a separatecolder cooling-water supply is used instead of the hot condensate
Motor-operated vacuum pumps can also be chosen these adaptreadily to automated remote operations The purchasers inquiryspecification should establish for the air removal package thesepoints choice ofsteam-jet air ejector or motor-driven vacuum pump motive steampressure and temperature hogging-ejector minimum operating time evacuating capacity of operating ejectorpackage (compared with Standards recommendation) standby
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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2 Revised 0606
Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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2 Revised 0606
accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
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160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
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Working of the Thermal Power Plant
Steam is generated in the boiler of the thermal power plant using heat of
the fuel burnt in the combustion chamber The steam generated is passedthrough steam turbine where part of its thermal energy is converted intomechanical energy which is further used for generating electric power Thesteam coming out of the steam turbine is condensed in the condenser andthe condensate is supplied back to the boiler with the help of the feedpump and the cycle is repeated The function of the Boiler is to generatesteam The function of the condenser is to condense the steam coming outof the low pressure turbine The function of the steam turbine is to convertheat energy into mechanical energy The function of the condenser is toincrease the pressure of the condensate from the condenser pressure to
the boiler pressure The other components like economizer super heaterair heater and feed water heaters are used in the primary circuit toincrease the overall efficiency of the plant
Site Selection of a Thermal Power Plant
The important aspect to be borne in mind during site selection for athermal power plant are availability of coal ash disposal facility spacerequirement nature of land availability of water transport facility
availability of labor public problems size of the plant
The different types of systems and components used insteam power plant are as follows
(i ) High pressure boiler(ii ) Prime mover(iii ) Condenser (iv ) Coal handling system
(v ) Ash and dust handling system(vi ) Draught system(vii ) Feed water purification plant(viii ) Pumping system(ix ) Air pre heater economizer super heater feed heaters
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1CoalThe coal is obtained primarily from Wyoming This is done in most casesbut coal may also be shipped by trucks or by pipelines Inside the powerplant there is an unloading dock where the carts of the rail are heated tomelt the snow on the rail carts before unloading them The coal is stored inhuge heaps or piles of a half a mile in diameter The reason for stocking
this much of coal is because the loss due to loss of generation due to lackof coal is very high The upper layer of the coal heap has to be compactedto make it into a airtight surface to prevent loss of coal due to oxidationOther methods of preventing oxidation are by keeping it under water or byspraying chemicals on it
2 Coal handling In plant coal handling is a very important aspect of power plant
safety In variably the coal is not exposed as it can pollute the air andrelease poisonous gases like carbon monoxide The coal from the heaps ismoved into the plant by means of long conveyors that are electricallyoperated There are many different types of conveyors and coal-handlingdevices like screwing conveyors bucket elevators grabbing bucketconveyors etc
3 Coal CrusherBefore the coal is sent to the plant it has to be ensured that the coal is ofuniform size and so it is passed through coal crushers Also power plants
using pulverized coal specify a maximum coal size that can be fed into thepulverizer and so the coal has to be crushed to the specified size using thecoal crusher Rotary crushers are very commonly used for this purpose asthey can provide a continuous flow of coal to the pulverizer
4PulverizerMost commonly used pulverizer is the Boul Mill The arrangement consistsof 2 stationary rollers and a power driven baul in which pulverization takesplace as the coal passes through the sides of the rollers and the baul Aprimary air induced draught fan draws a stream of heated air through the
mill carrying the pulverized coal into a stationary classifier at the top of thepulverizer The classifier separates the pulverized coal from theunpulverized coalAdvantages of pulverized coal
bull Pulverized coal is used for large capacity plants
bull It is easier to adapt to fluctuating load as there are no limitationson the combustion capacity
bull Coal with higher ash percentage cannot be used with outpulverizing because of the problem of large amount ash deposition aftercombustion
bull
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bull Increased thermal efficiency is obtained through pulverization
bull The use of secondary air in the combustion chamber along withthe powered coal helps in creating
turbulence and therefore uniform mixing of the coal and the air duringcombustion
bull Greater surface area of coal per unit mass of coal allows fastercombustion as more coal is exposed to heat and combustion
bull The combustion process is almost free from clinker and slagformation
bull The boiler can be easily started from cold condition incase ofemergency
bull Practically no ash handling problem
bull The furnace volume required is less as the turbulence caused
aids in complete combustion of the coal with minimum travel of theparticlesThe pulverized coal is passed from the pulverizer to the boiler by means ofthe primary air that is used not only to dry the coal but also to heat is as itgoes into the boiler The secondary air is used to provide the necessary airrequired for complete combustion The primary air may vary anywherefrom 10 to the entire air depending on the design of the boiler The coalis sent into the boiler through burners A very important and widely usedtype of burner arrangement is the Tangential Firing arrangement
Tangential Burners
The tangential burners are arranged such that they discharge the fuel airmixture tangentially to an imaginary circle in the center of the furnace Theswirling action produces sufficient turbulence in the furnace to completethe combustion in a short period of time and avoid the necessity ofproducing high turbulence at the burner itself High heat release rates arepossible with this method of firing
The burners are placed at the four corners of the furnace At the ColumbiaPower Plant six sets of such burners are placed one above the other toform six firing zones These burners are constructed with tips that can
be angled through a small vertical arc By adjusting the angle of theburners the position of the fire ball can be adjusted so as to raise or lowerthe position of the turbulent combustion region When the burners are tilteddownward the furnace gets filled completely with the flame and the furnaceexit gas temperature gets reduced When the burners are tiled upward thefurnace exit gas temperature increases A difference of 100 degrees canbe achieved by tilting the burners
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5Ash Handling
The ever increasing capacities of boiler units together with their ability touse low grade high ash content coal have been responsible for thedevelopment of modern day ash handling systems The widely used ashhandling systems are
1 Mechanical Handling System2 Hydraulic System3 Pneumatic System4 Steam Jet SystemThe Hydraulic Ash handling system is used at the Columbia Power Plant
Hydraulic Ash Handling System
The hydraulic system carried the ash with the flow of water with high
velocity through a channel and finally dumps into a sump The hydraulicsystem is divided into a low velocity and high velocity system In the lowvelocity system the ash from the boilers fall into a stream of water flowinginto the sump The ash is carried along with the water and they areseparated at the sump In the high velocity system a jet of water is sprayedto quench the hot ash Two other jets force the ash into a trough in whichthey are washed away by the water into the sump where they areseparated The molten slag formed in the pulverized fuel system can alsobe quenched and washed by using the high velocity system Theadvantages of this system are that its clean large ash handling capacityconsiderable distance can be traversed absence of working parts incontact with ash
6High Pressure Boiler
It is a common practice to use high pressure and temperature boilers toincrease the efficiency of the plant and to decrease the cost of electricityproduction The boiler at the power plant is a water tube boiler whichmeans that water that is converted to steam is passed through the tubesinside the boiler The tubes are bent back and forth many times to ensurethat all the water is converted to steam Wet steam is not desirable when it
goes to the turbine as it may cause corrosion on the turbine blades A highpressure boiler is not a simple assemble of certain components likeburners super heaters air heaters and others The function of thecomponents is interrelated The location of the heat transfer surfaces isvery important and it depends on the required duty of the boiler and thequality of the coal used The most commonly used furnace layout orpulverized is shown in the figure In zone 1 heat transfer is primarily byradiation As the gases move upward and secondary air is added theeffect of radiation is reduced and convection becomes predominant Theheat transfer in Zone 2 and Zone 3 takes place mainly by convection
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Zones 2 being a high temperature zone and Zone 3 being the lowtemperature zone The evaporators are placed in the Zone 1 as it isdesirable to have lowest possible tube metal surface temperature becauseof AFT (ash fusion temperature) issues Since the Zone 2 has hightemperatures slagging is an important concern in this zone The excessheat is removed by using panels or platens which may either be superheaters or evaporators The Zone 3 because of comparatively lowtemperatures is ideally suited for heat recovery equipment likeeconomizers and air pre heaters
7 Boiler Accessories
A large amount of fuel is used in thermal power plant and very largeamount of heat is generated and carried by waste gases The loss wouldbe very high if the waste gases carry all the heat away The loss can hehalved by installing an economizer and a pre- heater in the path of thewaste gases The economizer transfers the heat from the waste gases tothe incoming feed water This reduces the heat required to convert thefeed water to steam The air pre heater increases the heat of the airsupplied into the boiler for combustion This increases the efficiency of theboiler
8 Economizer
The economizer is a feed water heater deriving heat from the flue gasesThe justifiable cost of the economizer depends on the total gain in
efficiency In turn this depends on the flue gas temperature leaving theboiler and the feed water inlet temperature A typical return bend typeeconomizer is shown in the figure
Types of economizerPlain Tube Economizer
These are generally used in case of boilers with natural draught The tubesare made of cast iron and their ends are pressed into top and bottomheaders The economizer is placed in the main flue gas path between theboiler and the chimney The waste flue gases flow outside the tubes and
heat is transferred to the water flowing inside High efficiency can beachieved by maintaining the water walls soot free
Grilled Tube Economizer
This is the type of economizer used in the power plant This type ofeconomizer reduced space considerably Rectangular grills are cast on thebare tube walls Economizer tubes may have finned tubes to increase theheat transfer rate Thicker fins offer greater efficiency than thinner onesbecause of greater surface area
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Air Pre-heater
The flue gases coming out of the economizer is used to preheat the airbefore supplying it to the combustion chamber An increase in airtemperature of 20 degrees can be achieved by this method The preheated air is used for combustion and also to dry the crushed coal beforepulverizing
Types of Air Heaters
Tubular Air HeaterThe flue gas flows outside the tubes in which the air flows heating it Toincrease the time of contact horizontal baffles are provided
Plate Type Air Heater
It consists of rectangular flat plates spaced 15 to 2 cm apart leavingalternate air and gas passages This is not used extensively as it involveshigh maintenance
Regenerative Air Heater
The transfer of heat from hot gas to cold air is done in 2 stages In the firststage the heat from the hot gases is passed to the packing of the airheater and the temperature of the gas is sufficiently reduced before lettingit out in the atmosphere This is called the heating period In the secondstage the heat from the packing is passed to the cold air This is called thecooling period
Soot Blowers
The fuel used in thermal power plants cause soot and this is deposited onthe boiler tubes economizer tubes air pre heaters etc This drasticallyreduces the amount of heat transfer of the heat exchangers Soot blowerscontrol the formation of soot and reduce its corrosive effects The types ofsoot blowers are fixed type which may be further classified into lane typeand mass type depending upon the type of spray and nozzle used Theother type of soot blower is the retractable soot blower The advantages
are that they are placed far away from the high temperature zone theyconcentrate the cleaning through a single large nozzle rather than manysmall nozzles and there is no concern of nozzle arrangement with respectto the boiler tubes
Condenser
The use of a condenser in a power plant is to improve the efficiency of thepower plant by decreasing the exhaust pressure of the steam belowatmosphere Another advantage of the condenser is that the steamcondensed may be recovered to provide a source of good pure feed water
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to the boiler an reduce the water softening capacity to a considerableextent A condenser is one of the essential components of a power plant
Types of Steam Condensers
Mixing or Jet Type Condenser These type of cndensers are mainly oftwo types Parallel flow type and Conunter flow type The parallel flow type
the steam and the water flow in the same direction and in the counter flowtype they flow in opposite directions These type are rarely used in highcapacity modern day power plants
Non Mixing Type or Surface Condensers In this type the cooling waterand steam do not come in contact with each other This is used wherelarge quantity of inferior quality water is available In this the cooling waterflows in pipes and the steam flows in a perpendicular direction to thepipes The velocity of water flowing is very high to absorb the heat from thesteam This condenser can be classified based on the number of passes
of the tube and the direction of the condensate flow and tube arrangementeither down flow or central flow
Cooling TowerThe importance of the cooling tower is felt when the cooling water from thecondenser has to be cooled The cooling water after condensing the steambecomes hot and it has to be cooled as it belongs to a closed system TheCooling towers do the job of decreasing the temperature of the coolingwater after condensing the steam in the condenser
The fan centered at the top of units draws air through two cells that arepaired to a suction chamber partitioned beneath the fan The outstandingfeature of this tower is lower air static pressure loss as there is lessresistance to air flow The evaporation and effective cooling of air isgreater when the air outside is warmer and dryer than when it is cold andalready saturated
Air Cooled Steam Condenser-
Air‐cooled steam condensers are increasingly employed to reject heat in
modern power plants
Air‐cooled condensers (ACCs) use ambient air to cool and condense a
process fluid Mechanical draft ACCs are used extensively in the chemicaland process industries and are finding increasing application in the globalelectric power producing industry due to economic and environmentalconsiderations
The generation of electric power is traditionally a water intensive activity
and with the sustainability of fresh water resources becoming a major
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concern in many parts of the world there is increasing pressure on thisindustry to find ways to reduce their fresh water consumption Modernthermoelectric power plants with steam turbines are equipped with acooling system to condense the turbine exhaust steam and maintain acertain turbine exhaust pressure (often referred to as turbinebackpressure) in a closed cycle )
Mechanical draft air‐
cooled steam condensers (ACSCs) consisting ofmultiple fan units are used in direct cooled thermoelectric power plantsto condense steam in a closed cycle using ambient air as the coolingmedium No water is directly consumed in the cooling process and assuch the total fresh water consumption of a power plant with an ACSC issignificantly less than one employing wet cooling There are a number ofadvantages over and above water consumption reduction such asincreased plant site flexibility and shortened licensing periodsassociated with the use of ACSCs
In a direct cooled steam turbine cycle with an ACSC low pressure steamis ducted from the turbine exhaust to steam headers that run along the
apex of a number of ACSC fan units (also referred to as A‐frame units or
cells) A typical forced draft ACSC fan unit consists of an axial flow fanlocated below a finned tube heat exchanger bundle The
steam condenses inside the finned tubes as a result of heat transfer toambient air forced through the heat exchanger by the fan The finned
tubes are typically arranged in an A‐ frame configuration for cooling
applications of this magnitude so as to maximize the available heat
transfer surface area while keeping the ACSC footprint to a minimumThe inclined tube configuration also aids in the effective drainage of thecondensate which is ultimately pumped back to the boiler or heat
recovery steam generator in the case of a combined‐cycle plant to
complete the closed cycle
Steam condensers coupled to the exhaust of these turbines returncondensate to the power cycle and boilerEither surface-type or air-cooled condensers can be selected The former have once-through orrecirculating water as the cooling medium while the latter are once-
through systems employing the atmosphere as the heat sink Amongthe advantages of air-cooled steam condensers compared with wetsystems are elimination of makeup water supply blowdown disposalwater-freezing problems water vapor plumes and concerns overgovernmental water-pollution restrictions Because of the dry nature ofthe equipment lowersystem-maintenance costs also result
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An air-cooled steam condenser system starts at the turbine exhaustflange It includes all of the equipment necessary to condense thesteam and return the condensate to the boiler feed water pipingThese items are
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1 Air-cooled steam condenser tower2 Air-flow control equipment3 Wind andor cell-partition walls4 Steam-bypass heating system5 Air removal equipment
6 Condensate storage tank7 Condensate pumps8 Steam ducts and expansion joints
9 Condensate drain and air-removal piping10 Instrumentation controls and alarms11 Pressure-relief device for protection of steam-turbine exhaustcasing12 Steam-duct condensate drain system
The basic air-cooled steam condenser includes the bundles steamdistribution manifold fans motors gear boxes and supporting steel Inlarge installations the cost of the tower structure supporting thecondenser bundles can be a substantial portion of the total cost Thestructures design specifications for wind load snow load live load andseismic requirements should be carefully chosen Generally grade-mounted towers cost less than roof-mounted ones
Limitations on plan dimensions must be made clear in the inquiryspecification Heat sources located close to the proposed tower and
discharging into the atmosphere must be identified The prevailingwind directions define the proper location and orientation of the towerwith respect to other large structures and heat sources Summer windsare important in the consideration of thermal performance and winterwinds in prescribing freeze-protection measures Noise limitationsshould also be stated since lower fan noise generally requires lowertip speed more fan blades and possibly wider blades
The purchaser should specify whether the thermal performanceguarantees are to be based on steam pressure measured at the
turbine exhaust flange or at the steam manifold inlet at thecondenser Other options are anall-welded system to reduce the potential for air leaks into the condenserand the use of extruded aluminum fins which provide longer trouble-freeoperation than embedded or wrap-on fins (these are prone to galvaniccorrosion because of their bimetallic tube-to-fin interface)
Airflow control equipment for freeze protection though an integral part ofthe engineered package supplied by the manufacturer nevertheless
reflects the purchasers preferences and needs Consideration should
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be given to variable-pitch fans air-flow control louvers steam isolatingvalves and two-speed motors The extra price of electric starters neededfor two-speed motors should be included
Wind walls are sometimes necessary to protect the bundles from windgusts that can upset equilibrium operating conditions and at times causefreezing in some remote parts of the tower Partition walls between fancells isolate operating cells from non operating ones Without partitionwalls a non operating fan would induce bypass of air intended for thebundles
Depending upon the minimum design ambient-air temperature the typeof turbine and the type of plant operation it may be economic to providea steam-bypass heating system for cold-weather startup This wouldoperate directly off the boiler requiring both a steam pressure-reducingstation and a de-superheating station with steam flow exhaustingdirectly into the main steam duct Part of the condenser heating steamduring startup would be supplied by the turbine exhaust and theremainder from this bypass system Alternatively large steam-isolatingvalves can be installed to supply condenser sections sequentially withsteam flows only from the turbine exhaust
The equipment extracting non condensables from the systemconsists of the hogging ejector and the operating ejectors Duringstartup the hogging ejector removes air from inside the turbinesteam ducts steam manifolds and bundles It reduces the airpressure within the system front atmospheric to about 10 in Hgabsolute in a time period
For the usual full-vacuum steam condenser a two-stage operatingejector system complete with condensers is normally provided with orwithout standby Its capacity is generally specified by the purchaser inaccord with the Heat Exchange Institute Standards for steam surfacecondensers Some purchasers add a safety allowance by doubling theventing capacity recommended in the standard Thc costliest parts of theejector package arc the inter- and after-condensers which are shell-and-tube construction These can be smaller and lower-cost if a separatecolder cooling-water supply is used instead of the hot condensate
Motor-operated vacuum pumps can also be chosen these adaptreadily to automated remote operations The purchasers inquiryspecification should establish for the air removal package thesepoints choice ofsteam-jet air ejector or motor-driven vacuum pump motive steampressure and temperature hogging-ejector minimum operating time evacuating capacity of operating ejectorpackage (compared with Standards recommendation) standby
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
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160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
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983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
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983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
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1CoalThe coal is obtained primarily from Wyoming This is done in most casesbut coal may also be shipped by trucks or by pipelines Inside the powerplant there is an unloading dock where the carts of the rail are heated tomelt the snow on the rail carts before unloading them The coal is stored inhuge heaps or piles of a half a mile in diameter The reason for stocking
this much of coal is because the loss due to loss of generation due to lackof coal is very high The upper layer of the coal heap has to be compactedto make it into a airtight surface to prevent loss of coal due to oxidationOther methods of preventing oxidation are by keeping it under water or byspraying chemicals on it
2 Coal handling In plant coal handling is a very important aspect of power plant
safety In variably the coal is not exposed as it can pollute the air andrelease poisonous gases like carbon monoxide The coal from the heaps ismoved into the plant by means of long conveyors that are electricallyoperated There are many different types of conveyors and coal-handlingdevices like screwing conveyors bucket elevators grabbing bucketconveyors etc
3 Coal CrusherBefore the coal is sent to the plant it has to be ensured that the coal is ofuniform size and so it is passed through coal crushers Also power plants
using pulverized coal specify a maximum coal size that can be fed into thepulverizer and so the coal has to be crushed to the specified size using thecoal crusher Rotary crushers are very commonly used for this purpose asthey can provide a continuous flow of coal to the pulverizer
4PulverizerMost commonly used pulverizer is the Boul Mill The arrangement consistsof 2 stationary rollers and a power driven baul in which pulverization takesplace as the coal passes through the sides of the rollers and the baul Aprimary air induced draught fan draws a stream of heated air through the
mill carrying the pulverized coal into a stationary classifier at the top of thepulverizer The classifier separates the pulverized coal from theunpulverized coalAdvantages of pulverized coal
bull Pulverized coal is used for large capacity plants
bull It is easier to adapt to fluctuating load as there are no limitationson the combustion capacity
bull Coal with higher ash percentage cannot be used with outpulverizing because of the problem of large amount ash deposition aftercombustion
bull
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bull Increased thermal efficiency is obtained through pulverization
bull The use of secondary air in the combustion chamber along withthe powered coal helps in creating
turbulence and therefore uniform mixing of the coal and the air duringcombustion
bull Greater surface area of coal per unit mass of coal allows fastercombustion as more coal is exposed to heat and combustion
bull The combustion process is almost free from clinker and slagformation
bull The boiler can be easily started from cold condition incase ofemergency
bull Practically no ash handling problem
bull The furnace volume required is less as the turbulence caused
aids in complete combustion of the coal with minimum travel of theparticlesThe pulverized coal is passed from the pulverizer to the boiler by means ofthe primary air that is used not only to dry the coal but also to heat is as itgoes into the boiler The secondary air is used to provide the necessary airrequired for complete combustion The primary air may vary anywherefrom 10 to the entire air depending on the design of the boiler The coalis sent into the boiler through burners A very important and widely usedtype of burner arrangement is the Tangential Firing arrangement
Tangential Burners
The tangential burners are arranged such that they discharge the fuel airmixture tangentially to an imaginary circle in the center of the furnace Theswirling action produces sufficient turbulence in the furnace to completethe combustion in a short period of time and avoid the necessity ofproducing high turbulence at the burner itself High heat release rates arepossible with this method of firing
The burners are placed at the four corners of the furnace At the ColumbiaPower Plant six sets of such burners are placed one above the other toform six firing zones These burners are constructed with tips that can
be angled through a small vertical arc By adjusting the angle of theburners the position of the fire ball can be adjusted so as to raise or lowerthe position of the turbulent combustion region When the burners are tilteddownward the furnace gets filled completely with the flame and the furnaceexit gas temperature gets reduced When the burners are tiled upward thefurnace exit gas temperature increases A difference of 100 degrees canbe achieved by tilting the burners
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5Ash Handling
The ever increasing capacities of boiler units together with their ability touse low grade high ash content coal have been responsible for thedevelopment of modern day ash handling systems The widely used ashhandling systems are
1 Mechanical Handling System2 Hydraulic System3 Pneumatic System4 Steam Jet SystemThe Hydraulic Ash handling system is used at the Columbia Power Plant
Hydraulic Ash Handling System
The hydraulic system carried the ash with the flow of water with high
velocity through a channel and finally dumps into a sump The hydraulicsystem is divided into a low velocity and high velocity system In the lowvelocity system the ash from the boilers fall into a stream of water flowinginto the sump The ash is carried along with the water and they areseparated at the sump In the high velocity system a jet of water is sprayedto quench the hot ash Two other jets force the ash into a trough in whichthey are washed away by the water into the sump where they areseparated The molten slag formed in the pulverized fuel system can alsobe quenched and washed by using the high velocity system Theadvantages of this system are that its clean large ash handling capacityconsiderable distance can be traversed absence of working parts incontact with ash
6High Pressure Boiler
It is a common practice to use high pressure and temperature boilers toincrease the efficiency of the plant and to decrease the cost of electricityproduction The boiler at the power plant is a water tube boiler whichmeans that water that is converted to steam is passed through the tubesinside the boiler The tubes are bent back and forth many times to ensurethat all the water is converted to steam Wet steam is not desirable when it
goes to the turbine as it may cause corrosion on the turbine blades A highpressure boiler is not a simple assemble of certain components likeburners super heaters air heaters and others The function of thecomponents is interrelated The location of the heat transfer surfaces isvery important and it depends on the required duty of the boiler and thequality of the coal used The most commonly used furnace layout orpulverized is shown in the figure In zone 1 heat transfer is primarily byradiation As the gases move upward and secondary air is added theeffect of radiation is reduced and convection becomes predominant Theheat transfer in Zone 2 and Zone 3 takes place mainly by convection
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Zones 2 being a high temperature zone and Zone 3 being the lowtemperature zone The evaporators are placed in the Zone 1 as it isdesirable to have lowest possible tube metal surface temperature becauseof AFT (ash fusion temperature) issues Since the Zone 2 has hightemperatures slagging is an important concern in this zone The excessheat is removed by using panels or platens which may either be superheaters or evaporators The Zone 3 because of comparatively lowtemperatures is ideally suited for heat recovery equipment likeeconomizers and air pre heaters
7 Boiler Accessories
A large amount of fuel is used in thermal power plant and very largeamount of heat is generated and carried by waste gases The loss wouldbe very high if the waste gases carry all the heat away The loss can hehalved by installing an economizer and a pre- heater in the path of thewaste gases The economizer transfers the heat from the waste gases tothe incoming feed water This reduces the heat required to convert thefeed water to steam The air pre heater increases the heat of the airsupplied into the boiler for combustion This increases the efficiency of theboiler
8 Economizer
The economizer is a feed water heater deriving heat from the flue gasesThe justifiable cost of the economizer depends on the total gain in
efficiency In turn this depends on the flue gas temperature leaving theboiler and the feed water inlet temperature A typical return bend typeeconomizer is shown in the figure
Types of economizerPlain Tube Economizer
These are generally used in case of boilers with natural draught The tubesare made of cast iron and their ends are pressed into top and bottomheaders The economizer is placed in the main flue gas path between theboiler and the chimney The waste flue gases flow outside the tubes and
heat is transferred to the water flowing inside High efficiency can beachieved by maintaining the water walls soot free
Grilled Tube Economizer
This is the type of economizer used in the power plant This type ofeconomizer reduced space considerably Rectangular grills are cast on thebare tube walls Economizer tubes may have finned tubes to increase theheat transfer rate Thicker fins offer greater efficiency than thinner onesbecause of greater surface area
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Air Pre-heater
The flue gases coming out of the economizer is used to preheat the airbefore supplying it to the combustion chamber An increase in airtemperature of 20 degrees can be achieved by this method The preheated air is used for combustion and also to dry the crushed coal beforepulverizing
Types of Air Heaters
Tubular Air HeaterThe flue gas flows outside the tubes in which the air flows heating it Toincrease the time of contact horizontal baffles are provided
Plate Type Air Heater
It consists of rectangular flat plates spaced 15 to 2 cm apart leavingalternate air and gas passages This is not used extensively as it involveshigh maintenance
Regenerative Air Heater
The transfer of heat from hot gas to cold air is done in 2 stages In the firststage the heat from the hot gases is passed to the packing of the airheater and the temperature of the gas is sufficiently reduced before lettingit out in the atmosphere This is called the heating period In the secondstage the heat from the packing is passed to the cold air This is called thecooling period
Soot Blowers
The fuel used in thermal power plants cause soot and this is deposited onthe boiler tubes economizer tubes air pre heaters etc This drasticallyreduces the amount of heat transfer of the heat exchangers Soot blowerscontrol the formation of soot and reduce its corrosive effects The types ofsoot blowers are fixed type which may be further classified into lane typeand mass type depending upon the type of spray and nozzle used Theother type of soot blower is the retractable soot blower The advantages
are that they are placed far away from the high temperature zone theyconcentrate the cleaning through a single large nozzle rather than manysmall nozzles and there is no concern of nozzle arrangement with respectto the boiler tubes
Condenser
The use of a condenser in a power plant is to improve the efficiency of thepower plant by decreasing the exhaust pressure of the steam belowatmosphere Another advantage of the condenser is that the steamcondensed may be recovered to provide a source of good pure feed water
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to the boiler an reduce the water softening capacity to a considerableextent A condenser is one of the essential components of a power plant
Types of Steam Condensers
Mixing or Jet Type Condenser These type of cndensers are mainly oftwo types Parallel flow type and Conunter flow type The parallel flow type
the steam and the water flow in the same direction and in the counter flowtype they flow in opposite directions These type are rarely used in highcapacity modern day power plants
Non Mixing Type or Surface Condensers In this type the cooling waterand steam do not come in contact with each other This is used wherelarge quantity of inferior quality water is available In this the cooling waterflows in pipes and the steam flows in a perpendicular direction to thepipes The velocity of water flowing is very high to absorb the heat from thesteam This condenser can be classified based on the number of passes
of the tube and the direction of the condensate flow and tube arrangementeither down flow or central flow
Cooling TowerThe importance of the cooling tower is felt when the cooling water from thecondenser has to be cooled The cooling water after condensing the steambecomes hot and it has to be cooled as it belongs to a closed system TheCooling towers do the job of decreasing the temperature of the coolingwater after condensing the steam in the condenser
The fan centered at the top of units draws air through two cells that arepaired to a suction chamber partitioned beneath the fan The outstandingfeature of this tower is lower air static pressure loss as there is lessresistance to air flow The evaporation and effective cooling of air isgreater when the air outside is warmer and dryer than when it is cold andalready saturated
Air Cooled Steam Condenser-
Air‐cooled steam condensers are increasingly employed to reject heat in
modern power plants
Air‐cooled condensers (ACCs) use ambient air to cool and condense a
process fluid Mechanical draft ACCs are used extensively in the chemicaland process industries and are finding increasing application in the globalelectric power producing industry due to economic and environmentalconsiderations
The generation of electric power is traditionally a water intensive activity
and with the sustainability of fresh water resources becoming a major
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concern in many parts of the world there is increasing pressure on thisindustry to find ways to reduce their fresh water consumption Modernthermoelectric power plants with steam turbines are equipped with acooling system to condense the turbine exhaust steam and maintain acertain turbine exhaust pressure (often referred to as turbinebackpressure) in a closed cycle )
Mechanical draft air‐
cooled steam condensers (ACSCs) consisting ofmultiple fan units are used in direct cooled thermoelectric power plantsto condense steam in a closed cycle using ambient air as the coolingmedium No water is directly consumed in the cooling process and assuch the total fresh water consumption of a power plant with an ACSC issignificantly less than one employing wet cooling There are a number ofadvantages over and above water consumption reduction such asincreased plant site flexibility and shortened licensing periodsassociated with the use of ACSCs
In a direct cooled steam turbine cycle with an ACSC low pressure steamis ducted from the turbine exhaust to steam headers that run along the
apex of a number of ACSC fan units (also referred to as A‐frame units or
cells) A typical forced draft ACSC fan unit consists of an axial flow fanlocated below a finned tube heat exchanger bundle The
steam condenses inside the finned tubes as a result of heat transfer toambient air forced through the heat exchanger by the fan The finned
tubes are typically arranged in an A‐ frame configuration for cooling
applications of this magnitude so as to maximize the available heat
transfer surface area while keeping the ACSC footprint to a minimumThe inclined tube configuration also aids in the effective drainage of thecondensate which is ultimately pumped back to the boiler or heat
recovery steam generator in the case of a combined‐cycle plant to
complete the closed cycle
Steam condensers coupled to the exhaust of these turbines returncondensate to the power cycle and boilerEither surface-type or air-cooled condensers can be selected The former have once-through orrecirculating water as the cooling medium while the latter are once-
through systems employing the atmosphere as the heat sink Amongthe advantages of air-cooled steam condensers compared with wetsystems are elimination of makeup water supply blowdown disposalwater-freezing problems water vapor plumes and concerns overgovernmental water-pollution restrictions Because of the dry nature ofthe equipment lowersystem-maintenance costs also result
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An air-cooled steam condenser system starts at the turbine exhaustflange It includes all of the equipment necessary to condense thesteam and return the condensate to the boiler feed water pipingThese items are
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1 Air-cooled steam condenser tower2 Air-flow control equipment3 Wind andor cell-partition walls4 Steam-bypass heating system5 Air removal equipment
6 Condensate storage tank7 Condensate pumps8 Steam ducts and expansion joints
9 Condensate drain and air-removal piping10 Instrumentation controls and alarms11 Pressure-relief device for protection of steam-turbine exhaustcasing12 Steam-duct condensate drain system
The basic air-cooled steam condenser includes the bundles steamdistribution manifold fans motors gear boxes and supporting steel Inlarge installations the cost of the tower structure supporting thecondenser bundles can be a substantial portion of the total cost Thestructures design specifications for wind load snow load live load andseismic requirements should be carefully chosen Generally grade-mounted towers cost less than roof-mounted ones
Limitations on plan dimensions must be made clear in the inquiryspecification Heat sources located close to the proposed tower and
discharging into the atmosphere must be identified The prevailingwind directions define the proper location and orientation of the towerwith respect to other large structures and heat sources Summer windsare important in the consideration of thermal performance and winterwinds in prescribing freeze-protection measures Noise limitationsshould also be stated since lower fan noise generally requires lowertip speed more fan blades and possibly wider blades
The purchaser should specify whether the thermal performanceguarantees are to be based on steam pressure measured at the
turbine exhaust flange or at the steam manifold inlet at thecondenser Other options are anall-welded system to reduce the potential for air leaks into the condenserand the use of extruded aluminum fins which provide longer trouble-freeoperation than embedded or wrap-on fins (these are prone to galvaniccorrosion because of their bimetallic tube-to-fin interface)
Airflow control equipment for freeze protection though an integral part ofthe engineered package supplied by the manufacturer nevertheless
reflects the purchasers preferences and needs Consideration should
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be given to variable-pitch fans air-flow control louvers steam isolatingvalves and two-speed motors The extra price of electric starters neededfor two-speed motors should be included
Wind walls are sometimes necessary to protect the bundles from windgusts that can upset equilibrium operating conditions and at times causefreezing in some remote parts of the tower Partition walls between fancells isolate operating cells from non operating ones Without partitionwalls a non operating fan would induce bypass of air intended for thebundles
Depending upon the minimum design ambient-air temperature the typeof turbine and the type of plant operation it may be economic to providea steam-bypass heating system for cold-weather startup This wouldoperate directly off the boiler requiring both a steam pressure-reducingstation and a de-superheating station with steam flow exhaustingdirectly into the main steam duct Part of the condenser heating steamduring startup would be supplied by the turbine exhaust and theremainder from this bypass system Alternatively large steam-isolatingvalves can be installed to supply condenser sections sequentially withsteam flows only from the turbine exhaust
The equipment extracting non condensables from the systemconsists of the hogging ejector and the operating ejectors Duringstartup the hogging ejector removes air from inside the turbinesteam ducts steam manifolds and bundles It reduces the airpressure within the system front atmospheric to about 10 in Hgabsolute in a time period
For the usual full-vacuum steam condenser a two-stage operatingejector system complete with condensers is normally provided with orwithout standby Its capacity is generally specified by the purchaser inaccord with the Heat Exchange Institute Standards for steam surfacecondensers Some purchasers add a safety allowance by doubling theventing capacity recommended in the standard Thc costliest parts of theejector package arc the inter- and after-condensers which are shell-and-tube construction These can be smaller and lower-cost if a separatecolder cooling-water supply is used instead of the hot condensate
Motor-operated vacuum pumps can also be chosen these adaptreadily to automated remote operations The purchasers inquiryspecification should establish for the air removal package thesepoints choice ofsteam-jet air ejector or motor-driven vacuum pump motive steampressure and temperature hogging-ejector minimum operating time evacuating capacity of operating ejectorpackage (compared with Standards recommendation) standby
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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2 Revised 0606
accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
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160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
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190
160
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bull Increased thermal efficiency is obtained through pulverization
bull The use of secondary air in the combustion chamber along withthe powered coal helps in creating
turbulence and therefore uniform mixing of the coal and the air duringcombustion
bull Greater surface area of coal per unit mass of coal allows fastercombustion as more coal is exposed to heat and combustion
bull The combustion process is almost free from clinker and slagformation
bull The boiler can be easily started from cold condition incase ofemergency
bull Practically no ash handling problem
bull The furnace volume required is less as the turbulence caused
aids in complete combustion of the coal with minimum travel of theparticlesThe pulverized coal is passed from the pulverizer to the boiler by means ofthe primary air that is used not only to dry the coal but also to heat is as itgoes into the boiler The secondary air is used to provide the necessary airrequired for complete combustion The primary air may vary anywherefrom 10 to the entire air depending on the design of the boiler The coalis sent into the boiler through burners A very important and widely usedtype of burner arrangement is the Tangential Firing arrangement
Tangential Burners
The tangential burners are arranged such that they discharge the fuel airmixture tangentially to an imaginary circle in the center of the furnace Theswirling action produces sufficient turbulence in the furnace to completethe combustion in a short period of time and avoid the necessity ofproducing high turbulence at the burner itself High heat release rates arepossible with this method of firing
The burners are placed at the four corners of the furnace At the ColumbiaPower Plant six sets of such burners are placed one above the other toform six firing zones These burners are constructed with tips that can
be angled through a small vertical arc By adjusting the angle of theburners the position of the fire ball can be adjusted so as to raise or lowerthe position of the turbulent combustion region When the burners are tilteddownward the furnace gets filled completely with the flame and the furnaceexit gas temperature gets reduced When the burners are tiled upward thefurnace exit gas temperature increases A difference of 100 degrees canbe achieved by tilting the burners
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5Ash Handling
The ever increasing capacities of boiler units together with their ability touse low grade high ash content coal have been responsible for thedevelopment of modern day ash handling systems The widely used ashhandling systems are
1 Mechanical Handling System2 Hydraulic System3 Pneumatic System4 Steam Jet SystemThe Hydraulic Ash handling system is used at the Columbia Power Plant
Hydraulic Ash Handling System
The hydraulic system carried the ash with the flow of water with high
velocity through a channel and finally dumps into a sump The hydraulicsystem is divided into a low velocity and high velocity system In the lowvelocity system the ash from the boilers fall into a stream of water flowinginto the sump The ash is carried along with the water and they areseparated at the sump In the high velocity system a jet of water is sprayedto quench the hot ash Two other jets force the ash into a trough in whichthey are washed away by the water into the sump where they areseparated The molten slag formed in the pulverized fuel system can alsobe quenched and washed by using the high velocity system Theadvantages of this system are that its clean large ash handling capacityconsiderable distance can be traversed absence of working parts incontact with ash
6High Pressure Boiler
It is a common practice to use high pressure and temperature boilers toincrease the efficiency of the plant and to decrease the cost of electricityproduction The boiler at the power plant is a water tube boiler whichmeans that water that is converted to steam is passed through the tubesinside the boiler The tubes are bent back and forth many times to ensurethat all the water is converted to steam Wet steam is not desirable when it
goes to the turbine as it may cause corrosion on the turbine blades A highpressure boiler is not a simple assemble of certain components likeburners super heaters air heaters and others The function of thecomponents is interrelated The location of the heat transfer surfaces isvery important and it depends on the required duty of the boiler and thequality of the coal used The most commonly used furnace layout orpulverized is shown in the figure In zone 1 heat transfer is primarily byradiation As the gases move upward and secondary air is added theeffect of radiation is reduced and convection becomes predominant Theheat transfer in Zone 2 and Zone 3 takes place mainly by convection
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Zones 2 being a high temperature zone and Zone 3 being the lowtemperature zone The evaporators are placed in the Zone 1 as it isdesirable to have lowest possible tube metal surface temperature becauseof AFT (ash fusion temperature) issues Since the Zone 2 has hightemperatures slagging is an important concern in this zone The excessheat is removed by using panels or platens which may either be superheaters or evaporators The Zone 3 because of comparatively lowtemperatures is ideally suited for heat recovery equipment likeeconomizers and air pre heaters
7 Boiler Accessories
A large amount of fuel is used in thermal power plant and very largeamount of heat is generated and carried by waste gases The loss wouldbe very high if the waste gases carry all the heat away The loss can hehalved by installing an economizer and a pre- heater in the path of thewaste gases The economizer transfers the heat from the waste gases tothe incoming feed water This reduces the heat required to convert thefeed water to steam The air pre heater increases the heat of the airsupplied into the boiler for combustion This increases the efficiency of theboiler
8 Economizer
The economizer is a feed water heater deriving heat from the flue gasesThe justifiable cost of the economizer depends on the total gain in
efficiency In turn this depends on the flue gas temperature leaving theboiler and the feed water inlet temperature A typical return bend typeeconomizer is shown in the figure
Types of economizerPlain Tube Economizer
These are generally used in case of boilers with natural draught The tubesare made of cast iron and their ends are pressed into top and bottomheaders The economizer is placed in the main flue gas path between theboiler and the chimney The waste flue gases flow outside the tubes and
heat is transferred to the water flowing inside High efficiency can beachieved by maintaining the water walls soot free
Grilled Tube Economizer
This is the type of economizer used in the power plant This type ofeconomizer reduced space considerably Rectangular grills are cast on thebare tube walls Economizer tubes may have finned tubes to increase theheat transfer rate Thicker fins offer greater efficiency than thinner onesbecause of greater surface area
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Air Pre-heater
The flue gases coming out of the economizer is used to preheat the airbefore supplying it to the combustion chamber An increase in airtemperature of 20 degrees can be achieved by this method The preheated air is used for combustion and also to dry the crushed coal beforepulverizing
Types of Air Heaters
Tubular Air HeaterThe flue gas flows outside the tubes in which the air flows heating it Toincrease the time of contact horizontal baffles are provided
Plate Type Air Heater
It consists of rectangular flat plates spaced 15 to 2 cm apart leavingalternate air and gas passages This is not used extensively as it involveshigh maintenance
Regenerative Air Heater
The transfer of heat from hot gas to cold air is done in 2 stages In the firststage the heat from the hot gases is passed to the packing of the airheater and the temperature of the gas is sufficiently reduced before lettingit out in the atmosphere This is called the heating period In the secondstage the heat from the packing is passed to the cold air This is called thecooling period
Soot Blowers
The fuel used in thermal power plants cause soot and this is deposited onthe boiler tubes economizer tubes air pre heaters etc This drasticallyreduces the amount of heat transfer of the heat exchangers Soot blowerscontrol the formation of soot and reduce its corrosive effects The types ofsoot blowers are fixed type which may be further classified into lane typeand mass type depending upon the type of spray and nozzle used Theother type of soot blower is the retractable soot blower The advantages
are that they are placed far away from the high temperature zone theyconcentrate the cleaning through a single large nozzle rather than manysmall nozzles and there is no concern of nozzle arrangement with respectto the boiler tubes
Condenser
The use of a condenser in a power plant is to improve the efficiency of thepower plant by decreasing the exhaust pressure of the steam belowatmosphere Another advantage of the condenser is that the steamcondensed may be recovered to provide a source of good pure feed water
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to the boiler an reduce the water softening capacity to a considerableextent A condenser is one of the essential components of a power plant
Types of Steam Condensers
Mixing or Jet Type Condenser These type of cndensers are mainly oftwo types Parallel flow type and Conunter flow type The parallel flow type
the steam and the water flow in the same direction and in the counter flowtype they flow in opposite directions These type are rarely used in highcapacity modern day power plants
Non Mixing Type or Surface Condensers In this type the cooling waterand steam do not come in contact with each other This is used wherelarge quantity of inferior quality water is available In this the cooling waterflows in pipes and the steam flows in a perpendicular direction to thepipes The velocity of water flowing is very high to absorb the heat from thesteam This condenser can be classified based on the number of passes
of the tube and the direction of the condensate flow and tube arrangementeither down flow or central flow
Cooling TowerThe importance of the cooling tower is felt when the cooling water from thecondenser has to be cooled The cooling water after condensing the steambecomes hot and it has to be cooled as it belongs to a closed system TheCooling towers do the job of decreasing the temperature of the coolingwater after condensing the steam in the condenser
The fan centered at the top of units draws air through two cells that arepaired to a suction chamber partitioned beneath the fan The outstandingfeature of this tower is lower air static pressure loss as there is lessresistance to air flow The evaporation and effective cooling of air isgreater when the air outside is warmer and dryer than when it is cold andalready saturated
Air Cooled Steam Condenser-
Air‐cooled steam condensers are increasingly employed to reject heat in
modern power plants
Air‐cooled condensers (ACCs) use ambient air to cool and condense a
process fluid Mechanical draft ACCs are used extensively in the chemicaland process industries and are finding increasing application in the globalelectric power producing industry due to economic and environmentalconsiderations
The generation of electric power is traditionally a water intensive activity
and with the sustainability of fresh water resources becoming a major
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concern in many parts of the world there is increasing pressure on thisindustry to find ways to reduce their fresh water consumption Modernthermoelectric power plants with steam turbines are equipped with acooling system to condense the turbine exhaust steam and maintain acertain turbine exhaust pressure (often referred to as turbinebackpressure) in a closed cycle )
Mechanical draft air‐
cooled steam condensers (ACSCs) consisting ofmultiple fan units are used in direct cooled thermoelectric power plantsto condense steam in a closed cycle using ambient air as the coolingmedium No water is directly consumed in the cooling process and assuch the total fresh water consumption of a power plant with an ACSC issignificantly less than one employing wet cooling There are a number ofadvantages over and above water consumption reduction such asincreased plant site flexibility and shortened licensing periodsassociated with the use of ACSCs
In a direct cooled steam turbine cycle with an ACSC low pressure steamis ducted from the turbine exhaust to steam headers that run along the
apex of a number of ACSC fan units (also referred to as A‐frame units or
cells) A typical forced draft ACSC fan unit consists of an axial flow fanlocated below a finned tube heat exchanger bundle The
steam condenses inside the finned tubes as a result of heat transfer toambient air forced through the heat exchanger by the fan The finned
tubes are typically arranged in an A‐ frame configuration for cooling
applications of this magnitude so as to maximize the available heat
transfer surface area while keeping the ACSC footprint to a minimumThe inclined tube configuration also aids in the effective drainage of thecondensate which is ultimately pumped back to the boiler or heat
recovery steam generator in the case of a combined‐cycle plant to
complete the closed cycle
Steam condensers coupled to the exhaust of these turbines returncondensate to the power cycle and boilerEither surface-type or air-cooled condensers can be selected The former have once-through orrecirculating water as the cooling medium while the latter are once-
through systems employing the atmosphere as the heat sink Amongthe advantages of air-cooled steam condensers compared with wetsystems are elimination of makeup water supply blowdown disposalwater-freezing problems water vapor plumes and concerns overgovernmental water-pollution restrictions Because of the dry nature ofthe equipment lowersystem-maintenance costs also result
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An air-cooled steam condenser system starts at the turbine exhaustflange It includes all of the equipment necessary to condense thesteam and return the condensate to the boiler feed water pipingThese items are
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1 Air-cooled steam condenser tower2 Air-flow control equipment3 Wind andor cell-partition walls4 Steam-bypass heating system5 Air removal equipment
6 Condensate storage tank7 Condensate pumps8 Steam ducts and expansion joints
9 Condensate drain and air-removal piping10 Instrumentation controls and alarms11 Pressure-relief device for protection of steam-turbine exhaustcasing12 Steam-duct condensate drain system
The basic air-cooled steam condenser includes the bundles steamdistribution manifold fans motors gear boxes and supporting steel Inlarge installations the cost of the tower structure supporting thecondenser bundles can be a substantial portion of the total cost Thestructures design specifications for wind load snow load live load andseismic requirements should be carefully chosen Generally grade-mounted towers cost less than roof-mounted ones
Limitations on plan dimensions must be made clear in the inquiryspecification Heat sources located close to the proposed tower and
discharging into the atmosphere must be identified The prevailingwind directions define the proper location and orientation of the towerwith respect to other large structures and heat sources Summer windsare important in the consideration of thermal performance and winterwinds in prescribing freeze-protection measures Noise limitationsshould also be stated since lower fan noise generally requires lowertip speed more fan blades and possibly wider blades
The purchaser should specify whether the thermal performanceguarantees are to be based on steam pressure measured at the
turbine exhaust flange or at the steam manifold inlet at thecondenser Other options are anall-welded system to reduce the potential for air leaks into the condenserand the use of extruded aluminum fins which provide longer trouble-freeoperation than embedded or wrap-on fins (these are prone to galvaniccorrosion because of their bimetallic tube-to-fin interface)
Airflow control equipment for freeze protection though an integral part ofthe engineered package supplied by the manufacturer nevertheless
reflects the purchasers preferences and needs Consideration should
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be given to variable-pitch fans air-flow control louvers steam isolatingvalves and two-speed motors The extra price of electric starters neededfor two-speed motors should be included
Wind walls are sometimes necessary to protect the bundles from windgusts that can upset equilibrium operating conditions and at times causefreezing in some remote parts of the tower Partition walls between fancells isolate operating cells from non operating ones Without partitionwalls a non operating fan would induce bypass of air intended for thebundles
Depending upon the minimum design ambient-air temperature the typeof turbine and the type of plant operation it may be economic to providea steam-bypass heating system for cold-weather startup This wouldoperate directly off the boiler requiring both a steam pressure-reducingstation and a de-superheating station with steam flow exhaustingdirectly into the main steam duct Part of the condenser heating steamduring startup would be supplied by the turbine exhaust and theremainder from this bypass system Alternatively large steam-isolatingvalves can be installed to supply condenser sections sequentially withsteam flows only from the turbine exhaust
The equipment extracting non condensables from the systemconsists of the hogging ejector and the operating ejectors Duringstartup the hogging ejector removes air from inside the turbinesteam ducts steam manifolds and bundles It reduces the airpressure within the system front atmospheric to about 10 in Hgabsolute in a time period
For the usual full-vacuum steam condenser a two-stage operatingejector system complete with condensers is normally provided with orwithout standby Its capacity is generally specified by the purchaser inaccord with the Heat Exchange Institute Standards for steam surfacecondensers Some purchasers add a safety allowance by doubling theventing capacity recommended in the standard Thc costliest parts of theejector package arc the inter- and after-condensers which are shell-and-tube construction These can be smaller and lower-cost if a separatecolder cooling-water supply is used instead of the hot condensate
Motor-operated vacuum pumps can also be chosen these adaptreadily to automated remote operations The purchasers inquiryspecification should establish for the air removal package thesepoints choice ofsteam-jet air ejector or motor-driven vacuum pump motive steampressure and temperature hogging-ejector minimum operating time evacuating capacity of operating ejectorpackage (compared with Standards recommendation) standby
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
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160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
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5Ash Handling
The ever increasing capacities of boiler units together with their ability touse low grade high ash content coal have been responsible for thedevelopment of modern day ash handling systems The widely used ashhandling systems are
1 Mechanical Handling System2 Hydraulic System3 Pneumatic System4 Steam Jet SystemThe Hydraulic Ash handling system is used at the Columbia Power Plant
Hydraulic Ash Handling System
The hydraulic system carried the ash with the flow of water with high
velocity through a channel and finally dumps into a sump The hydraulicsystem is divided into a low velocity and high velocity system In the lowvelocity system the ash from the boilers fall into a stream of water flowinginto the sump The ash is carried along with the water and they areseparated at the sump In the high velocity system a jet of water is sprayedto quench the hot ash Two other jets force the ash into a trough in whichthey are washed away by the water into the sump where they areseparated The molten slag formed in the pulverized fuel system can alsobe quenched and washed by using the high velocity system Theadvantages of this system are that its clean large ash handling capacityconsiderable distance can be traversed absence of working parts incontact with ash
6High Pressure Boiler
It is a common practice to use high pressure and temperature boilers toincrease the efficiency of the plant and to decrease the cost of electricityproduction The boiler at the power plant is a water tube boiler whichmeans that water that is converted to steam is passed through the tubesinside the boiler The tubes are bent back and forth many times to ensurethat all the water is converted to steam Wet steam is not desirable when it
goes to the turbine as it may cause corrosion on the turbine blades A highpressure boiler is not a simple assemble of certain components likeburners super heaters air heaters and others The function of thecomponents is interrelated The location of the heat transfer surfaces isvery important and it depends on the required duty of the boiler and thequality of the coal used The most commonly used furnace layout orpulverized is shown in the figure In zone 1 heat transfer is primarily byradiation As the gases move upward and secondary air is added theeffect of radiation is reduced and convection becomes predominant Theheat transfer in Zone 2 and Zone 3 takes place mainly by convection
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Zones 2 being a high temperature zone and Zone 3 being the lowtemperature zone The evaporators are placed in the Zone 1 as it isdesirable to have lowest possible tube metal surface temperature becauseof AFT (ash fusion temperature) issues Since the Zone 2 has hightemperatures slagging is an important concern in this zone The excessheat is removed by using panels or platens which may either be superheaters or evaporators The Zone 3 because of comparatively lowtemperatures is ideally suited for heat recovery equipment likeeconomizers and air pre heaters
7 Boiler Accessories
A large amount of fuel is used in thermal power plant and very largeamount of heat is generated and carried by waste gases The loss wouldbe very high if the waste gases carry all the heat away The loss can hehalved by installing an economizer and a pre- heater in the path of thewaste gases The economizer transfers the heat from the waste gases tothe incoming feed water This reduces the heat required to convert thefeed water to steam The air pre heater increases the heat of the airsupplied into the boiler for combustion This increases the efficiency of theboiler
8 Economizer
The economizer is a feed water heater deriving heat from the flue gasesThe justifiable cost of the economizer depends on the total gain in
efficiency In turn this depends on the flue gas temperature leaving theboiler and the feed water inlet temperature A typical return bend typeeconomizer is shown in the figure
Types of economizerPlain Tube Economizer
These are generally used in case of boilers with natural draught The tubesare made of cast iron and their ends are pressed into top and bottomheaders The economizer is placed in the main flue gas path between theboiler and the chimney The waste flue gases flow outside the tubes and
heat is transferred to the water flowing inside High efficiency can beachieved by maintaining the water walls soot free
Grilled Tube Economizer
This is the type of economizer used in the power plant This type ofeconomizer reduced space considerably Rectangular grills are cast on thebare tube walls Economizer tubes may have finned tubes to increase theheat transfer rate Thicker fins offer greater efficiency than thinner onesbecause of greater surface area
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Air Pre-heater
The flue gases coming out of the economizer is used to preheat the airbefore supplying it to the combustion chamber An increase in airtemperature of 20 degrees can be achieved by this method The preheated air is used for combustion and also to dry the crushed coal beforepulverizing
Types of Air Heaters
Tubular Air HeaterThe flue gas flows outside the tubes in which the air flows heating it Toincrease the time of contact horizontal baffles are provided
Plate Type Air Heater
It consists of rectangular flat plates spaced 15 to 2 cm apart leavingalternate air and gas passages This is not used extensively as it involveshigh maintenance
Regenerative Air Heater
The transfer of heat from hot gas to cold air is done in 2 stages In the firststage the heat from the hot gases is passed to the packing of the airheater and the temperature of the gas is sufficiently reduced before lettingit out in the atmosphere This is called the heating period In the secondstage the heat from the packing is passed to the cold air This is called thecooling period
Soot Blowers
The fuel used in thermal power plants cause soot and this is deposited onthe boiler tubes economizer tubes air pre heaters etc This drasticallyreduces the amount of heat transfer of the heat exchangers Soot blowerscontrol the formation of soot and reduce its corrosive effects The types ofsoot blowers are fixed type which may be further classified into lane typeand mass type depending upon the type of spray and nozzle used Theother type of soot blower is the retractable soot blower The advantages
are that they are placed far away from the high temperature zone theyconcentrate the cleaning through a single large nozzle rather than manysmall nozzles and there is no concern of nozzle arrangement with respectto the boiler tubes
Condenser
The use of a condenser in a power plant is to improve the efficiency of thepower plant by decreasing the exhaust pressure of the steam belowatmosphere Another advantage of the condenser is that the steamcondensed may be recovered to provide a source of good pure feed water
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to the boiler an reduce the water softening capacity to a considerableextent A condenser is one of the essential components of a power plant
Types of Steam Condensers
Mixing or Jet Type Condenser These type of cndensers are mainly oftwo types Parallel flow type and Conunter flow type The parallel flow type
the steam and the water flow in the same direction and in the counter flowtype they flow in opposite directions These type are rarely used in highcapacity modern day power plants
Non Mixing Type or Surface Condensers In this type the cooling waterand steam do not come in contact with each other This is used wherelarge quantity of inferior quality water is available In this the cooling waterflows in pipes and the steam flows in a perpendicular direction to thepipes The velocity of water flowing is very high to absorb the heat from thesteam This condenser can be classified based on the number of passes
of the tube and the direction of the condensate flow and tube arrangementeither down flow or central flow
Cooling TowerThe importance of the cooling tower is felt when the cooling water from thecondenser has to be cooled The cooling water after condensing the steambecomes hot and it has to be cooled as it belongs to a closed system TheCooling towers do the job of decreasing the temperature of the coolingwater after condensing the steam in the condenser
The fan centered at the top of units draws air through two cells that arepaired to a suction chamber partitioned beneath the fan The outstandingfeature of this tower is lower air static pressure loss as there is lessresistance to air flow The evaporation and effective cooling of air isgreater when the air outside is warmer and dryer than when it is cold andalready saturated
Air Cooled Steam Condenser-
Air‐cooled steam condensers are increasingly employed to reject heat in
modern power plants
Air‐cooled condensers (ACCs) use ambient air to cool and condense a
process fluid Mechanical draft ACCs are used extensively in the chemicaland process industries and are finding increasing application in the globalelectric power producing industry due to economic and environmentalconsiderations
The generation of electric power is traditionally a water intensive activity
and with the sustainability of fresh water resources becoming a major
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concern in many parts of the world there is increasing pressure on thisindustry to find ways to reduce their fresh water consumption Modernthermoelectric power plants with steam turbines are equipped with acooling system to condense the turbine exhaust steam and maintain acertain turbine exhaust pressure (often referred to as turbinebackpressure) in a closed cycle )
Mechanical draft air‐
cooled steam condensers (ACSCs) consisting ofmultiple fan units are used in direct cooled thermoelectric power plantsto condense steam in a closed cycle using ambient air as the coolingmedium No water is directly consumed in the cooling process and assuch the total fresh water consumption of a power plant with an ACSC issignificantly less than one employing wet cooling There are a number ofadvantages over and above water consumption reduction such asincreased plant site flexibility and shortened licensing periodsassociated with the use of ACSCs
In a direct cooled steam turbine cycle with an ACSC low pressure steamis ducted from the turbine exhaust to steam headers that run along the
apex of a number of ACSC fan units (also referred to as A‐frame units or
cells) A typical forced draft ACSC fan unit consists of an axial flow fanlocated below a finned tube heat exchanger bundle The
steam condenses inside the finned tubes as a result of heat transfer toambient air forced through the heat exchanger by the fan The finned
tubes are typically arranged in an A‐ frame configuration for cooling
applications of this magnitude so as to maximize the available heat
transfer surface area while keeping the ACSC footprint to a minimumThe inclined tube configuration also aids in the effective drainage of thecondensate which is ultimately pumped back to the boiler or heat
recovery steam generator in the case of a combined‐cycle plant to
complete the closed cycle
Steam condensers coupled to the exhaust of these turbines returncondensate to the power cycle and boilerEither surface-type or air-cooled condensers can be selected The former have once-through orrecirculating water as the cooling medium while the latter are once-
through systems employing the atmosphere as the heat sink Amongthe advantages of air-cooled steam condensers compared with wetsystems are elimination of makeup water supply blowdown disposalwater-freezing problems water vapor plumes and concerns overgovernmental water-pollution restrictions Because of the dry nature ofthe equipment lowersystem-maintenance costs also result
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An air-cooled steam condenser system starts at the turbine exhaustflange It includes all of the equipment necessary to condense thesteam and return the condensate to the boiler feed water pipingThese items are
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1 Air-cooled steam condenser tower2 Air-flow control equipment3 Wind andor cell-partition walls4 Steam-bypass heating system5 Air removal equipment
6 Condensate storage tank7 Condensate pumps8 Steam ducts and expansion joints
9 Condensate drain and air-removal piping10 Instrumentation controls and alarms11 Pressure-relief device for protection of steam-turbine exhaustcasing12 Steam-duct condensate drain system
The basic air-cooled steam condenser includes the bundles steamdistribution manifold fans motors gear boxes and supporting steel Inlarge installations the cost of the tower structure supporting thecondenser bundles can be a substantial portion of the total cost Thestructures design specifications for wind load snow load live load andseismic requirements should be carefully chosen Generally grade-mounted towers cost less than roof-mounted ones
Limitations on plan dimensions must be made clear in the inquiryspecification Heat sources located close to the proposed tower and
discharging into the atmosphere must be identified The prevailingwind directions define the proper location and orientation of the towerwith respect to other large structures and heat sources Summer windsare important in the consideration of thermal performance and winterwinds in prescribing freeze-protection measures Noise limitationsshould also be stated since lower fan noise generally requires lowertip speed more fan blades and possibly wider blades
The purchaser should specify whether the thermal performanceguarantees are to be based on steam pressure measured at the
turbine exhaust flange or at the steam manifold inlet at thecondenser Other options are anall-welded system to reduce the potential for air leaks into the condenserand the use of extruded aluminum fins which provide longer trouble-freeoperation than embedded or wrap-on fins (these are prone to galvaniccorrosion because of their bimetallic tube-to-fin interface)
Airflow control equipment for freeze protection though an integral part ofthe engineered package supplied by the manufacturer nevertheless
reflects the purchasers preferences and needs Consideration should
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be given to variable-pitch fans air-flow control louvers steam isolatingvalves and two-speed motors The extra price of electric starters neededfor two-speed motors should be included
Wind walls are sometimes necessary to protect the bundles from windgusts that can upset equilibrium operating conditions and at times causefreezing in some remote parts of the tower Partition walls between fancells isolate operating cells from non operating ones Without partitionwalls a non operating fan would induce bypass of air intended for thebundles
Depending upon the minimum design ambient-air temperature the typeof turbine and the type of plant operation it may be economic to providea steam-bypass heating system for cold-weather startup This wouldoperate directly off the boiler requiring both a steam pressure-reducingstation and a de-superheating station with steam flow exhaustingdirectly into the main steam duct Part of the condenser heating steamduring startup would be supplied by the turbine exhaust and theremainder from this bypass system Alternatively large steam-isolatingvalves can be installed to supply condenser sections sequentially withsteam flows only from the turbine exhaust
The equipment extracting non condensables from the systemconsists of the hogging ejector and the operating ejectors Duringstartup the hogging ejector removes air from inside the turbinesteam ducts steam manifolds and bundles It reduces the airpressure within the system front atmospheric to about 10 in Hgabsolute in a time period
For the usual full-vacuum steam condenser a two-stage operatingejector system complete with condensers is normally provided with orwithout standby Its capacity is generally specified by the purchaser inaccord with the Heat Exchange Institute Standards for steam surfacecondensers Some purchasers add a safety allowance by doubling theventing capacity recommended in the standard Thc costliest parts of theejector package arc the inter- and after-condensers which are shell-and-tube construction These can be smaller and lower-cost if a separatecolder cooling-water supply is used instead of the hot condensate
Motor-operated vacuum pumps can also be chosen these adaptreadily to automated remote operations The purchasers inquiryspecification should establish for the air removal package thesepoints choice ofsteam-jet air ejector or motor-driven vacuum pump motive steampressure and temperature hogging-ejector minimum operating time evacuating capacity of operating ejectorpackage (compared with Standards recommendation) standby
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
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160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
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Zones 2 being a high temperature zone and Zone 3 being the lowtemperature zone The evaporators are placed in the Zone 1 as it isdesirable to have lowest possible tube metal surface temperature becauseof AFT (ash fusion temperature) issues Since the Zone 2 has hightemperatures slagging is an important concern in this zone The excessheat is removed by using panels or platens which may either be superheaters or evaporators The Zone 3 because of comparatively lowtemperatures is ideally suited for heat recovery equipment likeeconomizers and air pre heaters
7 Boiler Accessories
A large amount of fuel is used in thermal power plant and very largeamount of heat is generated and carried by waste gases The loss wouldbe very high if the waste gases carry all the heat away The loss can hehalved by installing an economizer and a pre- heater in the path of thewaste gases The economizer transfers the heat from the waste gases tothe incoming feed water This reduces the heat required to convert thefeed water to steam The air pre heater increases the heat of the airsupplied into the boiler for combustion This increases the efficiency of theboiler
8 Economizer
The economizer is a feed water heater deriving heat from the flue gasesThe justifiable cost of the economizer depends on the total gain in
efficiency In turn this depends on the flue gas temperature leaving theboiler and the feed water inlet temperature A typical return bend typeeconomizer is shown in the figure
Types of economizerPlain Tube Economizer
These are generally used in case of boilers with natural draught The tubesare made of cast iron and their ends are pressed into top and bottomheaders The economizer is placed in the main flue gas path between theboiler and the chimney The waste flue gases flow outside the tubes and
heat is transferred to the water flowing inside High efficiency can beachieved by maintaining the water walls soot free
Grilled Tube Economizer
This is the type of economizer used in the power plant This type ofeconomizer reduced space considerably Rectangular grills are cast on thebare tube walls Economizer tubes may have finned tubes to increase theheat transfer rate Thicker fins offer greater efficiency than thinner onesbecause of greater surface area
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Air Pre-heater
The flue gases coming out of the economizer is used to preheat the airbefore supplying it to the combustion chamber An increase in airtemperature of 20 degrees can be achieved by this method The preheated air is used for combustion and also to dry the crushed coal beforepulverizing
Types of Air Heaters
Tubular Air HeaterThe flue gas flows outside the tubes in which the air flows heating it Toincrease the time of contact horizontal baffles are provided
Plate Type Air Heater
It consists of rectangular flat plates spaced 15 to 2 cm apart leavingalternate air and gas passages This is not used extensively as it involveshigh maintenance
Regenerative Air Heater
The transfer of heat from hot gas to cold air is done in 2 stages In the firststage the heat from the hot gases is passed to the packing of the airheater and the temperature of the gas is sufficiently reduced before lettingit out in the atmosphere This is called the heating period In the secondstage the heat from the packing is passed to the cold air This is called thecooling period
Soot Blowers
The fuel used in thermal power plants cause soot and this is deposited onthe boiler tubes economizer tubes air pre heaters etc This drasticallyreduces the amount of heat transfer of the heat exchangers Soot blowerscontrol the formation of soot and reduce its corrosive effects The types ofsoot blowers are fixed type which may be further classified into lane typeand mass type depending upon the type of spray and nozzle used Theother type of soot blower is the retractable soot blower The advantages
are that they are placed far away from the high temperature zone theyconcentrate the cleaning through a single large nozzle rather than manysmall nozzles and there is no concern of nozzle arrangement with respectto the boiler tubes
Condenser
The use of a condenser in a power plant is to improve the efficiency of thepower plant by decreasing the exhaust pressure of the steam belowatmosphere Another advantage of the condenser is that the steamcondensed may be recovered to provide a source of good pure feed water
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to the boiler an reduce the water softening capacity to a considerableextent A condenser is one of the essential components of a power plant
Types of Steam Condensers
Mixing or Jet Type Condenser These type of cndensers are mainly oftwo types Parallel flow type and Conunter flow type The parallel flow type
the steam and the water flow in the same direction and in the counter flowtype they flow in opposite directions These type are rarely used in highcapacity modern day power plants
Non Mixing Type or Surface Condensers In this type the cooling waterand steam do not come in contact with each other This is used wherelarge quantity of inferior quality water is available In this the cooling waterflows in pipes and the steam flows in a perpendicular direction to thepipes The velocity of water flowing is very high to absorb the heat from thesteam This condenser can be classified based on the number of passes
of the tube and the direction of the condensate flow and tube arrangementeither down flow or central flow
Cooling TowerThe importance of the cooling tower is felt when the cooling water from thecondenser has to be cooled The cooling water after condensing the steambecomes hot and it has to be cooled as it belongs to a closed system TheCooling towers do the job of decreasing the temperature of the coolingwater after condensing the steam in the condenser
The fan centered at the top of units draws air through two cells that arepaired to a suction chamber partitioned beneath the fan The outstandingfeature of this tower is lower air static pressure loss as there is lessresistance to air flow The evaporation and effective cooling of air isgreater when the air outside is warmer and dryer than when it is cold andalready saturated
Air Cooled Steam Condenser-
Air‐cooled steam condensers are increasingly employed to reject heat in
modern power plants
Air‐cooled condensers (ACCs) use ambient air to cool and condense a
process fluid Mechanical draft ACCs are used extensively in the chemicaland process industries and are finding increasing application in the globalelectric power producing industry due to economic and environmentalconsiderations
The generation of electric power is traditionally a water intensive activity
and with the sustainability of fresh water resources becoming a major
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concern in many parts of the world there is increasing pressure on thisindustry to find ways to reduce their fresh water consumption Modernthermoelectric power plants with steam turbines are equipped with acooling system to condense the turbine exhaust steam and maintain acertain turbine exhaust pressure (often referred to as turbinebackpressure) in a closed cycle )
Mechanical draft air‐
cooled steam condensers (ACSCs) consisting ofmultiple fan units are used in direct cooled thermoelectric power plantsto condense steam in a closed cycle using ambient air as the coolingmedium No water is directly consumed in the cooling process and assuch the total fresh water consumption of a power plant with an ACSC issignificantly less than one employing wet cooling There are a number ofadvantages over and above water consumption reduction such asincreased plant site flexibility and shortened licensing periodsassociated with the use of ACSCs
In a direct cooled steam turbine cycle with an ACSC low pressure steamis ducted from the turbine exhaust to steam headers that run along the
apex of a number of ACSC fan units (also referred to as A‐frame units or
cells) A typical forced draft ACSC fan unit consists of an axial flow fanlocated below a finned tube heat exchanger bundle The
steam condenses inside the finned tubes as a result of heat transfer toambient air forced through the heat exchanger by the fan The finned
tubes are typically arranged in an A‐ frame configuration for cooling
applications of this magnitude so as to maximize the available heat
transfer surface area while keeping the ACSC footprint to a minimumThe inclined tube configuration also aids in the effective drainage of thecondensate which is ultimately pumped back to the boiler or heat
recovery steam generator in the case of a combined‐cycle plant to
complete the closed cycle
Steam condensers coupled to the exhaust of these turbines returncondensate to the power cycle and boilerEither surface-type or air-cooled condensers can be selected The former have once-through orrecirculating water as the cooling medium while the latter are once-
through systems employing the atmosphere as the heat sink Amongthe advantages of air-cooled steam condensers compared with wetsystems are elimination of makeup water supply blowdown disposalwater-freezing problems water vapor plumes and concerns overgovernmental water-pollution restrictions Because of the dry nature ofthe equipment lowersystem-maintenance costs also result
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An air-cooled steam condenser system starts at the turbine exhaustflange It includes all of the equipment necessary to condense thesteam and return the condensate to the boiler feed water pipingThese items are
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1 Air-cooled steam condenser tower2 Air-flow control equipment3 Wind andor cell-partition walls4 Steam-bypass heating system5 Air removal equipment
6 Condensate storage tank7 Condensate pumps8 Steam ducts and expansion joints
9 Condensate drain and air-removal piping10 Instrumentation controls and alarms11 Pressure-relief device for protection of steam-turbine exhaustcasing12 Steam-duct condensate drain system
The basic air-cooled steam condenser includes the bundles steamdistribution manifold fans motors gear boxes and supporting steel Inlarge installations the cost of the tower structure supporting thecondenser bundles can be a substantial portion of the total cost Thestructures design specifications for wind load snow load live load andseismic requirements should be carefully chosen Generally grade-mounted towers cost less than roof-mounted ones
Limitations on plan dimensions must be made clear in the inquiryspecification Heat sources located close to the proposed tower and
discharging into the atmosphere must be identified The prevailingwind directions define the proper location and orientation of the towerwith respect to other large structures and heat sources Summer windsare important in the consideration of thermal performance and winterwinds in prescribing freeze-protection measures Noise limitationsshould also be stated since lower fan noise generally requires lowertip speed more fan blades and possibly wider blades
The purchaser should specify whether the thermal performanceguarantees are to be based on steam pressure measured at the
turbine exhaust flange or at the steam manifold inlet at thecondenser Other options are anall-welded system to reduce the potential for air leaks into the condenserand the use of extruded aluminum fins which provide longer trouble-freeoperation than embedded or wrap-on fins (these are prone to galvaniccorrosion because of their bimetallic tube-to-fin interface)
Airflow control equipment for freeze protection though an integral part ofthe engineered package supplied by the manufacturer nevertheless
reflects the purchasers preferences and needs Consideration should
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be given to variable-pitch fans air-flow control louvers steam isolatingvalves and two-speed motors The extra price of electric starters neededfor two-speed motors should be included
Wind walls are sometimes necessary to protect the bundles from windgusts that can upset equilibrium operating conditions and at times causefreezing in some remote parts of the tower Partition walls between fancells isolate operating cells from non operating ones Without partitionwalls a non operating fan would induce bypass of air intended for thebundles
Depending upon the minimum design ambient-air temperature the typeof turbine and the type of plant operation it may be economic to providea steam-bypass heating system for cold-weather startup This wouldoperate directly off the boiler requiring both a steam pressure-reducingstation and a de-superheating station with steam flow exhaustingdirectly into the main steam duct Part of the condenser heating steamduring startup would be supplied by the turbine exhaust and theremainder from this bypass system Alternatively large steam-isolatingvalves can be installed to supply condenser sections sequentially withsteam flows only from the turbine exhaust
The equipment extracting non condensables from the systemconsists of the hogging ejector and the operating ejectors Duringstartup the hogging ejector removes air from inside the turbinesteam ducts steam manifolds and bundles It reduces the airpressure within the system front atmospheric to about 10 in Hgabsolute in a time period
For the usual full-vacuum steam condenser a two-stage operatingejector system complete with condensers is normally provided with orwithout standby Its capacity is generally specified by the purchaser inaccord with the Heat Exchange Institute Standards for steam surfacecondensers Some purchasers add a safety allowance by doubling theventing capacity recommended in the standard Thc costliest parts of theejector package arc the inter- and after-condensers which are shell-and-tube construction These can be smaller and lower-cost if a separatecolder cooling-water supply is used instead of the hot condensate
Motor-operated vacuum pumps can also be chosen these adaptreadily to automated remote operations The purchasers inquiryspecification should establish for the air removal package thesepoints choice ofsteam-jet air ejector or motor-driven vacuum pump motive steampressure and temperature hogging-ejector minimum operating time evacuating capacity of operating ejectorpackage (compared with Standards recommendation) standby
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
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160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
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Air Pre-heater
The flue gases coming out of the economizer is used to preheat the airbefore supplying it to the combustion chamber An increase in airtemperature of 20 degrees can be achieved by this method The preheated air is used for combustion and also to dry the crushed coal beforepulverizing
Types of Air Heaters
Tubular Air HeaterThe flue gas flows outside the tubes in which the air flows heating it Toincrease the time of contact horizontal baffles are provided
Plate Type Air Heater
It consists of rectangular flat plates spaced 15 to 2 cm apart leavingalternate air and gas passages This is not used extensively as it involveshigh maintenance
Regenerative Air Heater
The transfer of heat from hot gas to cold air is done in 2 stages In the firststage the heat from the hot gases is passed to the packing of the airheater and the temperature of the gas is sufficiently reduced before lettingit out in the atmosphere This is called the heating period In the secondstage the heat from the packing is passed to the cold air This is called thecooling period
Soot Blowers
The fuel used in thermal power plants cause soot and this is deposited onthe boiler tubes economizer tubes air pre heaters etc This drasticallyreduces the amount of heat transfer of the heat exchangers Soot blowerscontrol the formation of soot and reduce its corrosive effects The types ofsoot blowers are fixed type which may be further classified into lane typeand mass type depending upon the type of spray and nozzle used Theother type of soot blower is the retractable soot blower The advantages
are that they are placed far away from the high temperature zone theyconcentrate the cleaning through a single large nozzle rather than manysmall nozzles and there is no concern of nozzle arrangement with respectto the boiler tubes
Condenser
The use of a condenser in a power plant is to improve the efficiency of thepower plant by decreasing the exhaust pressure of the steam belowatmosphere Another advantage of the condenser is that the steamcondensed may be recovered to provide a source of good pure feed water
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to the boiler an reduce the water softening capacity to a considerableextent A condenser is one of the essential components of a power plant
Types of Steam Condensers
Mixing or Jet Type Condenser These type of cndensers are mainly oftwo types Parallel flow type and Conunter flow type The parallel flow type
the steam and the water flow in the same direction and in the counter flowtype they flow in opposite directions These type are rarely used in highcapacity modern day power plants
Non Mixing Type or Surface Condensers In this type the cooling waterand steam do not come in contact with each other This is used wherelarge quantity of inferior quality water is available In this the cooling waterflows in pipes and the steam flows in a perpendicular direction to thepipes The velocity of water flowing is very high to absorb the heat from thesteam This condenser can be classified based on the number of passes
of the tube and the direction of the condensate flow and tube arrangementeither down flow or central flow
Cooling TowerThe importance of the cooling tower is felt when the cooling water from thecondenser has to be cooled The cooling water after condensing the steambecomes hot and it has to be cooled as it belongs to a closed system TheCooling towers do the job of decreasing the temperature of the coolingwater after condensing the steam in the condenser
The fan centered at the top of units draws air through two cells that arepaired to a suction chamber partitioned beneath the fan The outstandingfeature of this tower is lower air static pressure loss as there is lessresistance to air flow The evaporation and effective cooling of air isgreater when the air outside is warmer and dryer than when it is cold andalready saturated
Air Cooled Steam Condenser-
Air‐cooled steam condensers are increasingly employed to reject heat in
modern power plants
Air‐cooled condensers (ACCs) use ambient air to cool and condense a
process fluid Mechanical draft ACCs are used extensively in the chemicaland process industries and are finding increasing application in the globalelectric power producing industry due to economic and environmentalconsiderations
The generation of electric power is traditionally a water intensive activity
and with the sustainability of fresh water resources becoming a major
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concern in many parts of the world there is increasing pressure on thisindustry to find ways to reduce their fresh water consumption Modernthermoelectric power plants with steam turbines are equipped with acooling system to condense the turbine exhaust steam and maintain acertain turbine exhaust pressure (often referred to as turbinebackpressure) in a closed cycle )
Mechanical draft air‐
cooled steam condensers (ACSCs) consisting ofmultiple fan units are used in direct cooled thermoelectric power plantsto condense steam in a closed cycle using ambient air as the coolingmedium No water is directly consumed in the cooling process and assuch the total fresh water consumption of a power plant with an ACSC issignificantly less than one employing wet cooling There are a number ofadvantages over and above water consumption reduction such asincreased plant site flexibility and shortened licensing periodsassociated with the use of ACSCs
In a direct cooled steam turbine cycle with an ACSC low pressure steamis ducted from the turbine exhaust to steam headers that run along the
apex of a number of ACSC fan units (also referred to as A‐frame units or
cells) A typical forced draft ACSC fan unit consists of an axial flow fanlocated below a finned tube heat exchanger bundle The
steam condenses inside the finned tubes as a result of heat transfer toambient air forced through the heat exchanger by the fan The finned
tubes are typically arranged in an A‐ frame configuration for cooling
applications of this magnitude so as to maximize the available heat
transfer surface area while keeping the ACSC footprint to a minimumThe inclined tube configuration also aids in the effective drainage of thecondensate which is ultimately pumped back to the boiler or heat
recovery steam generator in the case of a combined‐cycle plant to
complete the closed cycle
Steam condensers coupled to the exhaust of these turbines returncondensate to the power cycle and boilerEither surface-type or air-cooled condensers can be selected The former have once-through orrecirculating water as the cooling medium while the latter are once-
through systems employing the atmosphere as the heat sink Amongthe advantages of air-cooled steam condensers compared with wetsystems are elimination of makeup water supply blowdown disposalwater-freezing problems water vapor plumes and concerns overgovernmental water-pollution restrictions Because of the dry nature ofthe equipment lowersystem-maintenance costs also result
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An air-cooled steam condenser system starts at the turbine exhaustflange It includes all of the equipment necessary to condense thesteam and return the condensate to the boiler feed water pipingThese items are
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1 Air-cooled steam condenser tower2 Air-flow control equipment3 Wind andor cell-partition walls4 Steam-bypass heating system5 Air removal equipment
6 Condensate storage tank7 Condensate pumps8 Steam ducts and expansion joints
9 Condensate drain and air-removal piping10 Instrumentation controls and alarms11 Pressure-relief device for protection of steam-turbine exhaustcasing12 Steam-duct condensate drain system
The basic air-cooled steam condenser includes the bundles steamdistribution manifold fans motors gear boxes and supporting steel Inlarge installations the cost of the tower structure supporting thecondenser bundles can be a substantial portion of the total cost Thestructures design specifications for wind load snow load live load andseismic requirements should be carefully chosen Generally grade-mounted towers cost less than roof-mounted ones
Limitations on plan dimensions must be made clear in the inquiryspecification Heat sources located close to the proposed tower and
discharging into the atmosphere must be identified The prevailingwind directions define the proper location and orientation of the towerwith respect to other large structures and heat sources Summer windsare important in the consideration of thermal performance and winterwinds in prescribing freeze-protection measures Noise limitationsshould also be stated since lower fan noise generally requires lowertip speed more fan blades and possibly wider blades
The purchaser should specify whether the thermal performanceguarantees are to be based on steam pressure measured at the
turbine exhaust flange or at the steam manifold inlet at thecondenser Other options are anall-welded system to reduce the potential for air leaks into the condenserand the use of extruded aluminum fins which provide longer trouble-freeoperation than embedded or wrap-on fins (these are prone to galvaniccorrosion because of their bimetallic tube-to-fin interface)
Airflow control equipment for freeze protection though an integral part ofthe engineered package supplied by the manufacturer nevertheless
reflects the purchasers preferences and needs Consideration should
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be given to variable-pitch fans air-flow control louvers steam isolatingvalves and two-speed motors The extra price of electric starters neededfor two-speed motors should be included
Wind walls are sometimes necessary to protect the bundles from windgusts that can upset equilibrium operating conditions and at times causefreezing in some remote parts of the tower Partition walls between fancells isolate operating cells from non operating ones Without partitionwalls a non operating fan would induce bypass of air intended for thebundles
Depending upon the minimum design ambient-air temperature the typeof turbine and the type of plant operation it may be economic to providea steam-bypass heating system for cold-weather startup This wouldoperate directly off the boiler requiring both a steam pressure-reducingstation and a de-superheating station with steam flow exhaustingdirectly into the main steam duct Part of the condenser heating steamduring startup would be supplied by the turbine exhaust and theremainder from this bypass system Alternatively large steam-isolatingvalves can be installed to supply condenser sections sequentially withsteam flows only from the turbine exhaust
The equipment extracting non condensables from the systemconsists of the hogging ejector and the operating ejectors Duringstartup the hogging ejector removes air from inside the turbinesteam ducts steam manifolds and bundles It reduces the airpressure within the system front atmospheric to about 10 in Hgabsolute in a time period
For the usual full-vacuum steam condenser a two-stage operatingejector system complete with condensers is normally provided with orwithout standby Its capacity is generally specified by the purchaser inaccord with the Heat Exchange Institute Standards for steam surfacecondensers Some purchasers add a safety allowance by doubling theventing capacity recommended in the standard Thc costliest parts of theejector package arc the inter- and after-condensers which are shell-and-tube construction These can be smaller and lower-cost if a separatecolder cooling-water supply is used instead of the hot condensate
Motor-operated vacuum pumps can also be chosen these adaptreadily to automated remote operations The purchasers inquiryspecification should establish for the air removal package thesepoints choice ofsteam-jet air ejector or motor-driven vacuum pump motive steampressure and temperature hogging-ejector minimum operating time evacuating capacity of operating ejectorpackage (compared with Standards recommendation) standby
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
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160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
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to the boiler an reduce the water softening capacity to a considerableextent A condenser is one of the essential components of a power plant
Types of Steam Condensers
Mixing or Jet Type Condenser These type of cndensers are mainly oftwo types Parallel flow type and Conunter flow type The parallel flow type
the steam and the water flow in the same direction and in the counter flowtype they flow in opposite directions These type are rarely used in highcapacity modern day power plants
Non Mixing Type or Surface Condensers In this type the cooling waterand steam do not come in contact with each other This is used wherelarge quantity of inferior quality water is available In this the cooling waterflows in pipes and the steam flows in a perpendicular direction to thepipes The velocity of water flowing is very high to absorb the heat from thesteam This condenser can be classified based on the number of passes
of the tube and the direction of the condensate flow and tube arrangementeither down flow or central flow
Cooling TowerThe importance of the cooling tower is felt when the cooling water from thecondenser has to be cooled The cooling water after condensing the steambecomes hot and it has to be cooled as it belongs to a closed system TheCooling towers do the job of decreasing the temperature of the coolingwater after condensing the steam in the condenser
The fan centered at the top of units draws air through two cells that arepaired to a suction chamber partitioned beneath the fan The outstandingfeature of this tower is lower air static pressure loss as there is lessresistance to air flow The evaporation and effective cooling of air isgreater when the air outside is warmer and dryer than when it is cold andalready saturated
Air Cooled Steam Condenser-
Air‐cooled steam condensers are increasingly employed to reject heat in
modern power plants
Air‐cooled condensers (ACCs) use ambient air to cool and condense a
process fluid Mechanical draft ACCs are used extensively in the chemicaland process industries and are finding increasing application in the globalelectric power producing industry due to economic and environmentalconsiderations
The generation of electric power is traditionally a water intensive activity
and with the sustainability of fresh water resources becoming a major
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concern in many parts of the world there is increasing pressure on thisindustry to find ways to reduce their fresh water consumption Modernthermoelectric power plants with steam turbines are equipped with acooling system to condense the turbine exhaust steam and maintain acertain turbine exhaust pressure (often referred to as turbinebackpressure) in a closed cycle )
Mechanical draft air‐
cooled steam condensers (ACSCs) consisting ofmultiple fan units are used in direct cooled thermoelectric power plantsto condense steam in a closed cycle using ambient air as the coolingmedium No water is directly consumed in the cooling process and assuch the total fresh water consumption of a power plant with an ACSC issignificantly less than one employing wet cooling There are a number ofadvantages over and above water consumption reduction such asincreased plant site flexibility and shortened licensing periodsassociated with the use of ACSCs
In a direct cooled steam turbine cycle with an ACSC low pressure steamis ducted from the turbine exhaust to steam headers that run along the
apex of a number of ACSC fan units (also referred to as A‐frame units or
cells) A typical forced draft ACSC fan unit consists of an axial flow fanlocated below a finned tube heat exchanger bundle The
steam condenses inside the finned tubes as a result of heat transfer toambient air forced through the heat exchanger by the fan The finned
tubes are typically arranged in an A‐ frame configuration for cooling
applications of this magnitude so as to maximize the available heat
transfer surface area while keeping the ACSC footprint to a minimumThe inclined tube configuration also aids in the effective drainage of thecondensate which is ultimately pumped back to the boiler or heat
recovery steam generator in the case of a combined‐cycle plant to
complete the closed cycle
Steam condensers coupled to the exhaust of these turbines returncondensate to the power cycle and boilerEither surface-type or air-cooled condensers can be selected The former have once-through orrecirculating water as the cooling medium while the latter are once-
through systems employing the atmosphere as the heat sink Amongthe advantages of air-cooled steam condensers compared with wetsystems are elimination of makeup water supply blowdown disposalwater-freezing problems water vapor plumes and concerns overgovernmental water-pollution restrictions Because of the dry nature ofthe equipment lowersystem-maintenance costs also result
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An air-cooled steam condenser system starts at the turbine exhaustflange It includes all of the equipment necessary to condense thesteam and return the condensate to the boiler feed water pipingThese items are
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1 Air-cooled steam condenser tower2 Air-flow control equipment3 Wind andor cell-partition walls4 Steam-bypass heating system5 Air removal equipment
6 Condensate storage tank7 Condensate pumps8 Steam ducts and expansion joints
9 Condensate drain and air-removal piping10 Instrumentation controls and alarms11 Pressure-relief device for protection of steam-turbine exhaustcasing12 Steam-duct condensate drain system
The basic air-cooled steam condenser includes the bundles steamdistribution manifold fans motors gear boxes and supporting steel Inlarge installations the cost of the tower structure supporting thecondenser bundles can be a substantial portion of the total cost Thestructures design specifications for wind load snow load live load andseismic requirements should be carefully chosen Generally grade-mounted towers cost less than roof-mounted ones
Limitations on plan dimensions must be made clear in the inquiryspecification Heat sources located close to the proposed tower and
discharging into the atmosphere must be identified The prevailingwind directions define the proper location and orientation of the towerwith respect to other large structures and heat sources Summer windsare important in the consideration of thermal performance and winterwinds in prescribing freeze-protection measures Noise limitationsshould also be stated since lower fan noise generally requires lowertip speed more fan blades and possibly wider blades
The purchaser should specify whether the thermal performanceguarantees are to be based on steam pressure measured at the
turbine exhaust flange or at the steam manifold inlet at thecondenser Other options are anall-welded system to reduce the potential for air leaks into the condenserand the use of extruded aluminum fins which provide longer trouble-freeoperation than embedded or wrap-on fins (these are prone to galvaniccorrosion because of their bimetallic tube-to-fin interface)
Airflow control equipment for freeze protection though an integral part ofthe engineered package supplied by the manufacturer nevertheless
reflects the purchasers preferences and needs Consideration should
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be given to variable-pitch fans air-flow control louvers steam isolatingvalves and two-speed motors The extra price of electric starters neededfor two-speed motors should be included
Wind walls are sometimes necessary to protect the bundles from windgusts that can upset equilibrium operating conditions and at times causefreezing in some remote parts of the tower Partition walls between fancells isolate operating cells from non operating ones Without partitionwalls a non operating fan would induce bypass of air intended for thebundles
Depending upon the minimum design ambient-air temperature the typeof turbine and the type of plant operation it may be economic to providea steam-bypass heating system for cold-weather startup This wouldoperate directly off the boiler requiring both a steam pressure-reducingstation and a de-superheating station with steam flow exhaustingdirectly into the main steam duct Part of the condenser heating steamduring startup would be supplied by the turbine exhaust and theremainder from this bypass system Alternatively large steam-isolatingvalves can be installed to supply condenser sections sequentially withsteam flows only from the turbine exhaust
The equipment extracting non condensables from the systemconsists of the hogging ejector and the operating ejectors Duringstartup the hogging ejector removes air from inside the turbinesteam ducts steam manifolds and bundles It reduces the airpressure within the system front atmospheric to about 10 in Hgabsolute in a time period
For the usual full-vacuum steam condenser a two-stage operatingejector system complete with condensers is normally provided with orwithout standby Its capacity is generally specified by the purchaser inaccord with the Heat Exchange Institute Standards for steam surfacecondensers Some purchasers add a safety allowance by doubling theventing capacity recommended in the standard Thc costliest parts of theejector package arc the inter- and after-condensers which are shell-and-tube construction These can be smaller and lower-cost if a separatecolder cooling-water supply is used instead of the hot condensate
Motor-operated vacuum pumps can also be chosen these adaptreadily to automated remote operations The purchasers inquiryspecification should establish for the air removal package thesepoints choice ofsteam-jet air ejector or motor-driven vacuum pump motive steampressure and temperature hogging-ejector minimum operating time evacuating capacity of operating ejectorpackage (compared with Standards recommendation) standby
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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2 Revised 0606
available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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2 Revised 0606
GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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2 Revised 0606
changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
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concern in many parts of the world there is increasing pressure on thisindustry to find ways to reduce their fresh water consumption Modernthermoelectric power plants with steam turbines are equipped with acooling system to condense the turbine exhaust steam and maintain acertain turbine exhaust pressure (often referred to as turbinebackpressure) in a closed cycle )
Mechanical draft air‐
cooled steam condensers (ACSCs) consisting ofmultiple fan units are used in direct cooled thermoelectric power plantsto condense steam in a closed cycle using ambient air as the coolingmedium No water is directly consumed in the cooling process and assuch the total fresh water consumption of a power plant with an ACSC issignificantly less than one employing wet cooling There are a number ofadvantages over and above water consumption reduction such asincreased plant site flexibility and shortened licensing periodsassociated with the use of ACSCs
In a direct cooled steam turbine cycle with an ACSC low pressure steamis ducted from the turbine exhaust to steam headers that run along the
apex of a number of ACSC fan units (also referred to as A‐frame units or
cells) A typical forced draft ACSC fan unit consists of an axial flow fanlocated below a finned tube heat exchanger bundle The
steam condenses inside the finned tubes as a result of heat transfer toambient air forced through the heat exchanger by the fan The finned
tubes are typically arranged in an A‐ frame configuration for cooling
applications of this magnitude so as to maximize the available heat
transfer surface area while keeping the ACSC footprint to a minimumThe inclined tube configuration also aids in the effective drainage of thecondensate which is ultimately pumped back to the boiler or heat
recovery steam generator in the case of a combined‐cycle plant to
complete the closed cycle
Steam condensers coupled to the exhaust of these turbines returncondensate to the power cycle and boilerEither surface-type or air-cooled condensers can be selected The former have once-through orrecirculating water as the cooling medium while the latter are once-
through systems employing the atmosphere as the heat sink Amongthe advantages of air-cooled steam condensers compared with wetsystems are elimination of makeup water supply blowdown disposalwater-freezing problems water vapor plumes and concerns overgovernmental water-pollution restrictions Because of the dry nature ofthe equipment lowersystem-maintenance costs also result
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An air-cooled steam condenser system starts at the turbine exhaustflange It includes all of the equipment necessary to condense thesteam and return the condensate to the boiler feed water pipingThese items are
8112019 Dry Cooling Systems12
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1 Air-cooled steam condenser tower2 Air-flow control equipment3 Wind andor cell-partition walls4 Steam-bypass heating system5 Air removal equipment
6 Condensate storage tank7 Condensate pumps8 Steam ducts and expansion joints
9 Condensate drain and air-removal piping10 Instrumentation controls and alarms11 Pressure-relief device for protection of steam-turbine exhaustcasing12 Steam-duct condensate drain system
The basic air-cooled steam condenser includes the bundles steamdistribution manifold fans motors gear boxes and supporting steel Inlarge installations the cost of the tower structure supporting thecondenser bundles can be a substantial portion of the total cost Thestructures design specifications for wind load snow load live load andseismic requirements should be carefully chosen Generally grade-mounted towers cost less than roof-mounted ones
Limitations on plan dimensions must be made clear in the inquiryspecification Heat sources located close to the proposed tower and
discharging into the atmosphere must be identified The prevailingwind directions define the proper location and orientation of the towerwith respect to other large structures and heat sources Summer windsare important in the consideration of thermal performance and winterwinds in prescribing freeze-protection measures Noise limitationsshould also be stated since lower fan noise generally requires lowertip speed more fan blades and possibly wider blades
The purchaser should specify whether the thermal performanceguarantees are to be based on steam pressure measured at the
turbine exhaust flange or at the steam manifold inlet at thecondenser Other options are anall-welded system to reduce the potential for air leaks into the condenserand the use of extruded aluminum fins which provide longer trouble-freeoperation than embedded or wrap-on fins (these are prone to galvaniccorrosion because of their bimetallic tube-to-fin interface)
Airflow control equipment for freeze protection though an integral part ofthe engineered package supplied by the manufacturer nevertheless
reflects the purchasers preferences and needs Consideration should
8112019 Dry Cooling Systems12
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be given to variable-pitch fans air-flow control louvers steam isolatingvalves and two-speed motors The extra price of electric starters neededfor two-speed motors should be included
Wind walls are sometimes necessary to protect the bundles from windgusts that can upset equilibrium operating conditions and at times causefreezing in some remote parts of the tower Partition walls between fancells isolate operating cells from non operating ones Without partitionwalls a non operating fan would induce bypass of air intended for thebundles
Depending upon the minimum design ambient-air temperature the typeof turbine and the type of plant operation it may be economic to providea steam-bypass heating system for cold-weather startup This wouldoperate directly off the boiler requiring both a steam pressure-reducingstation and a de-superheating station with steam flow exhaustingdirectly into the main steam duct Part of the condenser heating steamduring startup would be supplied by the turbine exhaust and theremainder from this bypass system Alternatively large steam-isolatingvalves can be installed to supply condenser sections sequentially withsteam flows only from the turbine exhaust
The equipment extracting non condensables from the systemconsists of the hogging ejector and the operating ejectors Duringstartup the hogging ejector removes air from inside the turbinesteam ducts steam manifolds and bundles It reduces the airpressure within the system front atmospheric to about 10 in Hgabsolute in a time period
For the usual full-vacuum steam condenser a two-stage operatingejector system complete with condensers is normally provided with orwithout standby Its capacity is generally specified by the purchaser inaccord with the Heat Exchange Institute Standards for steam surfacecondensers Some purchasers add a safety allowance by doubling theventing capacity recommended in the standard Thc costliest parts of theejector package arc the inter- and after-condensers which are shell-and-tube construction These can be smaller and lower-cost if a separatecolder cooling-water supply is used instead of the hot condensate
Motor-operated vacuum pumps can also be chosen these adaptreadily to automated remote operations The purchasers inquiryspecification should establish for the air removal package thesepoints choice ofsteam-jet air ejector or motor-driven vacuum pump motive steampressure and temperature hogging-ejector minimum operating time evacuating capacity of operating ejectorpackage (compared with Standards recommendation) standby
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
8112019 Dry Cooling Systems12
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
8112019 Dry Cooling Systems12
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
8112019 Dry Cooling Systems12
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2 Revised 0606
Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
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160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
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An air-cooled steam condenser system starts at the turbine exhaustflange It includes all of the equipment necessary to condense thesteam and return the condensate to the boiler feed water pipingThese items are
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1 Air-cooled steam condenser tower2 Air-flow control equipment3 Wind andor cell-partition walls4 Steam-bypass heating system5 Air removal equipment
6 Condensate storage tank7 Condensate pumps8 Steam ducts and expansion joints
9 Condensate drain and air-removal piping10 Instrumentation controls and alarms11 Pressure-relief device for protection of steam-turbine exhaustcasing12 Steam-duct condensate drain system
The basic air-cooled steam condenser includes the bundles steamdistribution manifold fans motors gear boxes and supporting steel Inlarge installations the cost of the tower structure supporting thecondenser bundles can be a substantial portion of the total cost Thestructures design specifications for wind load snow load live load andseismic requirements should be carefully chosen Generally grade-mounted towers cost less than roof-mounted ones
Limitations on plan dimensions must be made clear in the inquiryspecification Heat sources located close to the proposed tower and
discharging into the atmosphere must be identified The prevailingwind directions define the proper location and orientation of the towerwith respect to other large structures and heat sources Summer windsare important in the consideration of thermal performance and winterwinds in prescribing freeze-protection measures Noise limitationsshould also be stated since lower fan noise generally requires lowertip speed more fan blades and possibly wider blades
The purchaser should specify whether the thermal performanceguarantees are to be based on steam pressure measured at the
turbine exhaust flange or at the steam manifold inlet at thecondenser Other options are anall-welded system to reduce the potential for air leaks into the condenserand the use of extruded aluminum fins which provide longer trouble-freeoperation than embedded or wrap-on fins (these are prone to galvaniccorrosion because of their bimetallic tube-to-fin interface)
Airflow control equipment for freeze protection though an integral part ofthe engineered package supplied by the manufacturer nevertheless
reflects the purchasers preferences and needs Consideration should
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be given to variable-pitch fans air-flow control louvers steam isolatingvalves and two-speed motors The extra price of electric starters neededfor two-speed motors should be included
Wind walls are sometimes necessary to protect the bundles from windgusts that can upset equilibrium operating conditions and at times causefreezing in some remote parts of the tower Partition walls between fancells isolate operating cells from non operating ones Without partitionwalls a non operating fan would induce bypass of air intended for thebundles
Depending upon the minimum design ambient-air temperature the typeof turbine and the type of plant operation it may be economic to providea steam-bypass heating system for cold-weather startup This wouldoperate directly off the boiler requiring both a steam pressure-reducingstation and a de-superheating station with steam flow exhaustingdirectly into the main steam duct Part of the condenser heating steamduring startup would be supplied by the turbine exhaust and theremainder from this bypass system Alternatively large steam-isolatingvalves can be installed to supply condenser sections sequentially withsteam flows only from the turbine exhaust
The equipment extracting non condensables from the systemconsists of the hogging ejector and the operating ejectors Duringstartup the hogging ejector removes air from inside the turbinesteam ducts steam manifolds and bundles It reduces the airpressure within the system front atmospheric to about 10 in Hgabsolute in a time period
For the usual full-vacuum steam condenser a two-stage operatingejector system complete with condensers is normally provided with orwithout standby Its capacity is generally specified by the purchaser inaccord with the Heat Exchange Institute Standards for steam surfacecondensers Some purchasers add a safety allowance by doubling theventing capacity recommended in the standard Thc costliest parts of theejector package arc the inter- and after-condensers which are shell-and-tube construction These can be smaller and lower-cost if a separatecolder cooling-water supply is used instead of the hot condensate
Motor-operated vacuum pumps can also be chosen these adaptreadily to automated remote operations The purchasers inquiryspecification should establish for the air removal package thesepoints choice ofsteam-jet air ejector or motor-driven vacuum pump motive steampressure and temperature hogging-ejector minimum operating time evacuating capacity of operating ejectorpackage (compared with Standards recommendation) standby
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
8112019 Dry Cooling Systems12
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
8112019 Dry Cooling Systems12
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
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160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
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An air-cooled steam condenser system starts at the turbine exhaustflange It includes all of the equipment necessary to condense thesteam and return the condensate to the boiler feed water pipingThese items are
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1 Air-cooled steam condenser tower2 Air-flow control equipment3 Wind andor cell-partition walls4 Steam-bypass heating system5 Air removal equipment
6 Condensate storage tank7 Condensate pumps8 Steam ducts and expansion joints
9 Condensate drain and air-removal piping10 Instrumentation controls and alarms11 Pressure-relief device for protection of steam-turbine exhaustcasing12 Steam-duct condensate drain system
The basic air-cooled steam condenser includes the bundles steamdistribution manifold fans motors gear boxes and supporting steel Inlarge installations the cost of the tower structure supporting thecondenser bundles can be a substantial portion of the total cost Thestructures design specifications for wind load snow load live load andseismic requirements should be carefully chosen Generally grade-mounted towers cost less than roof-mounted ones
Limitations on plan dimensions must be made clear in the inquiryspecification Heat sources located close to the proposed tower and
discharging into the atmosphere must be identified The prevailingwind directions define the proper location and orientation of the towerwith respect to other large structures and heat sources Summer windsare important in the consideration of thermal performance and winterwinds in prescribing freeze-protection measures Noise limitationsshould also be stated since lower fan noise generally requires lowertip speed more fan blades and possibly wider blades
The purchaser should specify whether the thermal performanceguarantees are to be based on steam pressure measured at the
turbine exhaust flange or at the steam manifold inlet at thecondenser Other options are anall-welded system to reduce the potential for air leaks into the condenserand the use of extruded aluminum fins which provide longer trouble-freeoperation than embedded or wrap-on fins (these are prone to galvaniccorrosion because of their bimetallic tube-to-fin interface)
Airflow control equipment for freeze protection though an integral part ofthe engineered package supplied by the manufacturer nevertheless
reflects the purchasers preferences and needs Consideration should
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be given to variable-pitch fans air-flow control louvers steam isolatingvalves and two-speed motors The extra price of electric starters neededfor two-speed motors should be included
Wind walls are sometimes necessary to protect the bundles from windgusts that can upset equilibrium operating conditions and at times causefreezing in some remote parts of the tower Partition walls between fancells isolate operating cells from non operating ones Without partitionwalls a non operating fan would induce bypass of air intended for thebundles
Depending upon the minimum design ambient-air temperature the typeof turbine and the type of plant operation it may be economic to providea steam-bypass heating system for cold-weather startup This wouldoperate directly off the boiler requiring both a steam pressure-reducingstation and a de-superheating station with steam flow exhaustingdirectly into the main steam duct Part of the condenser heating steamduring startup would be supplied by the turbine exhaust and theremainder from this bypass system Alternatively large steam-isolatingvalves can be installed to supply condenser sections sequentially withsteam flows only from the turbine exhaust
The equipment extracting non condensables from the systemconsists of the hogging ejector and the operating ejectors Duringstartup the hogging ejector removes air from inside the turbinesteam ducts steam manifolds and bundles It reduces the airpressure within the system front atmospheric to about 10 in Hgabsolute in a time period
For the usual full-vacuum steam condenser a two-stage operatingejector system complete with condensers is normally provided with orwithout standby Its capacity is generally specified by the purchaser inaccord with the Heat Exchange Institute Standards for steam surfacecondensers Some purchasers add a safety allowance by doubling theventing capacity recommended in the standard Thc costliest parts of theejector package arc the inter- and after-condensers which are shell-and-tube construction These can be smaller and lower-cost if a separatecolder cooling-water supply is used instead of the hot condensate
Motor-operated vacuum pumps can also be chosen these adaptreadily to automated remote operations The purchasers inquiryspecification should establish for the air removal package thesepoints choice ofsteam-jet air ejector or motor-driven vacuum pump motive steampressure and temperature hogging-ejector minimum operating time evacuating capacity of operating ejectorpackage (compared with Standards recommendation) standby
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
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160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
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An air-cooled steam condenser system starts at the turbine exhaustflange It includes all of the equipment necessary to condense thesteam and return the condensate to the boiler feed water pipingThese items are
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1 Air-cooled steam condenser tower2 Air-flow control equipment3 Wind andor cell-partition walls4 Steam-bypass heating system5 Air removal equipment
6 Condensate storage tank7 Condensate pumps8 Steam ducts and expansion joints
9 Condensate drain and air-removal piping10 Instrumentation controls and alarms11 Pressure-relief device for protection of steam-turbine exhaustcasing12 Steam-duct condensate drain system
The basic air-cooled steam condenser includes the bundles steamdistribution manifold fans motors gear boxes and supporting steel Inlarge installations the cost of the tower structure supporting thecondenser bundles can be a substantial portion of the total cost Thestructures design specifications for wind load snow load live load andseismic requirements should be carefully chosen Generally grade-mounted towers cost less than roof-mounted ones
Limitations on plan dimensions must be made clear in the inquiryspecification Heat sources located close to the proposed tower and
discharging into the atmosphere must be identified The prevailingwind directions define the proper location and orientation of the towerwith respect to other large structures and heat sources Summer windsare important in the consideration of thermal performance and winterwinds in prescribing freeze-protection measures Noise limitationsshould also be stated since lower fan noise generally requires lowertip speed more fan blades and possibly wider blades
The purchaser should specify whether the thermal performanceguarantees are to be based on steam pressure measured at the
turbine exhaust flange or at the steam manifold inlet at thecondenser Other options are anall-welded system to reduce the potential for air leaks into the condenserand the use of extruded aluminum fins which provide longer trouble-freeoperation than embedded or wrap-on fins (these are prone to galvaniccorrosion because of their bimetallic tube-to-fin interface)
Airflow control equipment for freeze protection though an integral part ofthe engineered package supplied by the manufacturer nevertheless
reflects the purchasers preferences and needs Consideration should
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be given to variable-pitch fans air-flow control louvers steam isolatingvalves and two-speed motors The extra price of electric starters neededfor two-speed motors should be included
Wind walls are sometimes necessary to protect the bundles from windgusts that can upset equilibrium operating conditions and at times causefreezing in some remote parts of the tower Partition walls between fancells isolate operating cells from non operating ones Without partitionwalls a non operating fan would induce bypass of air intended for thebundles
Depending upon the minimum design ambient-air temperature the typeof turbine and the type of plant operation it may be economic to providea steam-bypass heating system for cold-weather startup This wouldoperate directly off the boiler requiring both a steam pressure-reducingstation and a de-superheating station with steam flow exhaustingdirectly into the main steam duct Part of the condenser heating steamduring startup would be supplied by the turbine exhaust and theremainder from this bypass system Alternatively large steam-isolatingvalves can be installed to supply condenser sections sequentially withsteam flows only from the turbine exhaust
The equipment extracting non condensables from the systemconsists of the hogging ejector and the operating ejectors Duringstartup the hogging ejector removes air from inside the turbinesteam ducts steam manifolds and bundles It reduces the airpressure within the system front atmospheric to about 10 in Hgabsolute in a time period
For the usual full-vacuum steam condenser a two-stage operatingejector system complete with condensers is normally provided with orwithout standby Its capacity is generally specified by the purchaser inaccord with the Heat Exchange Institute Standards for steam surfacecondensers Some purchasers add a safety allowance by doubling theventing capacity recommended in the standard Thc costliest parts of theejector package arc the inter- and after-condensers which are shell-and-tube construction These can be smaller and lower-cost if a separatecolder cooling-water supply is used instead of the hot condensate
Motor-operated vacuum pumps can also be chosen these adaptreadily to automated remote operations The purchasers inquiryspecification should establish for the air removal package thesepoints choice ofsteam-jet air ejector or motor-driven vacuum pump motive steampressure and temperature hogging-ejector minimum operating time evacuating capacity of operating ejectorpackage (compared with Standards recommendation) standby
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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2 Revised 0606
Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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2 Revised 0606
accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
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160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
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An air-cooled steam condenser system starts at the turbine exhaustflange It includes all of the equipment necessary to condense thesteam and return the condensate to the boiler feed water pipingThese items are
8112019 Dry Cooling Systems12
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1 Air-cooled steam condenser tower2 Air-flow control equipment3 Wind andor cell-partition walls4 Steam-bypass heating system5 Air removal equipment
6 Condensate storage tank7 Condensate pumps8 Steam ducts and expansion joints
9 Condensate drain and air-removal piping10 Instrumentation controls and alarms11 Pressure-relief device for protection of steam-turbine exhaustcasing12 Steam-duct condensate drain system
The basic air-cooled steam condenser includes the bundles steamdistribution manifold fans motors gear boxes and supporting steel Inlarge installations the cost of the tower structure supporting thecondenser bundles can be a substantial portion of the total cost Thestructures design specifications for wind load snow load live load andseismic requirements should be carefully chosen Generally grade-mounted towers cost less than roof-mounted ones
Limitations on plan dimensions must be made clear in the inquiryspecification Heat sources located close to the proposed tower and
discharging into the atmosphere must be identified The prevailingwind directions define the proper location and orientation of the towerwith respect to other large structures and heat sources Summer windsare important in the consideration of thermal performance and winterwinds in prescribing freeze-protection measures Noise limitationsshould also be stated since lower fan noise generally requires lowertip speed more fan blades and possibly wider blades
The purchaser should specify whether the thermal performanceguarantees are to be based on steam pressure measured at the
turbine exhaust flange or at the steam manifold inlet at thecondenser Other options are anall-welded system to reduce the potential for air leaks into the condenserand the use of extruded aluminum fins which provide longer trouble-freeoperation than embedded or wrap-on fins (these are prone to galvaniccorrosion because of their bimetallic tube-to-fin interface)
Airflow control equipment for freeze protection though an integral part ofthe engineered package supplied by the manufacturer nevertheless
reflects the purchasers preferences and needs Consideration should
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be given to variable-pitch fans air-flow control louvers steam isolatingvalves and two-speed motors The extra price of electric starters neededfor two-speed motors should be included
Wind walls are sometimes necessary to protect the bundles from windgusts that can upset equilibrium operating conditions and at times causefreezing in some remote parts of the tower Partition walls between fancells isolate operating cells from non operating ones Without partitionwalls a non operating fan would induce bypass of air intended for thebundles
Depending upon the minimum design ambient-air temperature the typeof turbine and the type of plant operation it may be economic to providea steam-bypass heating system for cold-weather startup This wouldoperate directly off the boiler requiring both a steam pressure-reducingstation and a de-superheating station with steam flow exhaustingdirectly into the main steam duct Part of the condenser heating steamduring startup would be supplied by the turbine exhaust and theremainder from this bypass system Alternatively large steam-isolatingvalves can be installed to supply condenser sections sequentially withsteam flows only from the turbine exhaust
The equipment extracting non condensables from the systemconsists of the hogging ejector and the operating ejectors Duringstartup the hogging ejector removes air from inside the turbinesteam ducts steam manifolds and bundles It reduces the airpressure within the system front atmospheric to about 10 in Hgabsolute in a time period
For the usual full-vacuum steam condenser a two-stage operatingejector system complete with condensers is normally provided with orwithout standby Its capacity is generally specified by the purchaser inaccord with the Heat Exchange Institute Standards for steam surfacecondensers Some purchasers add a safety allowance by doubling theventing capacity recommended in the standard Thc costliest parts of theejector package arc the inter- and after-condensers which are shell-and-tube construction These can be smaller and lower-cost if a separatecolder cooling-water supply is used instead of the hot condensate
Motor-operated vacuum pumps can also be chosen these adaptreadily to automated remote operations The purchasers inquiryspecification should establish for the air removal package thesepoints choice ofsteam-jet air ejector or motor-driven vacuum pump motive steampressure and temperature hogging-ejector minimum operating time evacuating capacity of operating ejectorpackage (compared with Standards recommendation) standby
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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2 Revised 0606
accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
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160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
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An air-cooled steam condenser system starts at the turbine exhaustflange It includes all of the equipment necessary to condense thesteam and return the condensate to the boiler feed water pipingThese items are
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1 Air-cooled steam condenser tower2 Air-flow control equipment3 Wind andor cell-partition walls4 Steam-bypass heating system5 Air removal equipment
6 Condensate storage tank7 Condensate pumps8 Steam ducts and expansion joints
9 Condensate drain and air-removal piping10 Instrumentation controls and alarms11 Pressure-relief device for protection of steam-turbine exhaustcasing12 Steam-duct condensate drain system
The basic air-cooled steam condenser includes the bundles steamdistribution manifold fans motors gear boxes and supporting steel Inlarge installations the cost of the tower structure supporting thecondenser bundles can be a substantial portion of the total cost Thestructures design specifications for wind load snow load live load andseismic requirements should be carefully chosen Generally grade-mounted towers cost less than roof-mounted ones
Limitations on plan dimensions must be made clear in the inquiryspecification Heat sources located close to the proposed tower and
discharging into the atmosphere must be identified The prevailingwind directions define the proper location and orientation of the towerwith respect to other large structures and heat sources Summer windsare important in the consideration of thermal performance and winterwinds in prescribing freeze-protection measures Noise limitationsshould also be stated since lower fan noise generally requires lowertip speed more fan blades and possibly wider blades
The purchaser should specify whether the thermal performanceguarantees are to be based on steam pressure measured at the
turbine exhaust flange or at the steam manifold inlet at thecondenser Other options are anall-welded system to reduce the potential for air leaks into the condenserand the use of extruded aluminum fins which provide longer trouble-freeoperation than embedded or wrap-on fins (these are prone to galvaniccorrosion because of their bimetallic tube-to-fin interface)
Airflow control equipment for freeze protection though an integral part ofthe engineered package supplied by the manufacturer nevertheless
reflects the purchasers preferences and needs Consideration should
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be given to variable-pitch fans air-flow control louvers steam isolatingvalves and two-speed motors The extra price of electric starters neededfor two-speed motors should be included
Wind walls are sometimes necessary to protect the bundles from windgusts that can upset equilibrium operating conditions and at times causefreezing in some remote parts of the tower Partition walls between fancells isolate operating cells from non operating ones Without partitionwalls a non operating fan would induce bypass of air intended for thebundles
Depending upon the minimum design ambient-air temperature the typeof turbine and the type of plant operation it may be economic to providea steam-bypass heating system for cold-weather startup This wouldoperate directly off the boiler requiring both a steam pressure-reducingstation and a de-superheating station with steam flow exhaustingdirectly into the main steam duct Part of the condenser heating steamduring startup would be supplied by the turbine exhaust and theremainder from this bypass system Alternatively large steam-isolatingvalves can be installed to supply condenser sections sequentially withsteam flows only from the turbine exhaust
The equipment extracting non condensables from the systemconsists of the hogging ejector and the operating ejectors Duringstartup the hogging ejector removes air from inside the turbinesteam ducts steam manifolds and bundles It reduces the airpressure within the system front atmospheric to about 10 in Hgabsolute in a time period
For the usual full-vacuum steam condenser a two-stage operatingejector system complete with condensers is normally provided with orwithout standby Its capacity is generally specified by the purchaser inaccord with the Heat Exchange Institute Standards for steam surfacecondensers Some purchasers add a safety allowance by doubling theventing capacity recommended in the standard Thc costliest parts of theejector package arc the inter- and after-condensers which are shell-and-tube construction These can be smaller and lower-cost if a separatecolder cooling-water supply is used instead of the hot condensate
Motor-operated vacuum pumps can also be chosen these adaptreadily to automated remote operations The purchasers inquiryspecification should establish for the air removal package thesepoints choice ofsteam-jet air ejector or motor-driven vacuum pump motive steampressure and temperature hogging-ejector minimum operating time evacuating capacity of operating ejectorpackage (compared with Standards recommendation) standby
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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2 Revised 0606
Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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2 Revised 0606
accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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2 Revised 0606
GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
8112019 Dry Cooling Systems12
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
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1 Air-cooled steam condenser tower2 Air-flow control equipment3 Wind andor cell-partition walls4 Steam-bypass heating system5 Air removal equipment
6 Condensate storage tank7 Condensate pumps8 Steam ducts and expansion joints
9 Condensate drain and air-removal piping10 Instrumentation controls and alarms11 Pressure-relief device for protection of steam-turbine exhaustcasing12 Steam-duct condensate drain system
The basic air-cooled steam condenser includes the bundles steamdistribution manifold fans motors gear boxes and supporting steel Inlarge installations the cost of the tower structure supporting thecondenser bundles can be a substantial portion of the total cost Thestructures design specifications for wind load snow load live load andseismic requirements should be carefully chosen Generally grade-mounted towers cost less than roof-mounted ones
Limitations on plan dimensions must be made clear in the inquiryspecification Heat sources located close to the proposed tower and
discharging into the atmosphere must be identified The prevailingwind directions define the proper location and orientation of the towerwith respect to other large structures and heat sources Summer windsare important in the consideration of thermal performance and winterwinds in prescribing freeze-protection measures Noise limitationsshould also be stated since lower fan noise generally requires lowertip speed more fan blades and possibly wider blades
The purchaser should specify whether the thermal performanceguarantees are to be based on steam pressure measured at the
turbine exhaust flange or at the steam manifold inlet at thecondenser Other options are anall-welded system to reduce the potential for air leaks into the condenserand the use of extruded aluminum fins which provide longer trouble-freeoperation than embedded or wrap-on fins (these are prone to galvaniccorrosion because of their bimetallic tube-to-fin interface)
Airflow control equipment for freeze protection though an integral part ofthe engineered package supplied by the manufacturer nevertheless
reflects the purchasers preferences and needs Consideration should
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be given to variable-pitch fans air-flow control louvers steam isolatingvalves and two-speed motors The extra price of electric starters neededfor two-speed motors should be included
Wind walls are sometimes necessary to protect the bundles from windgusts that can upset equilibrium operating conditions and at times causefreezing in some remote parts of the tower Partition walls between fancells isolate operating cells from non operating ones Without partitionwalls a non operating fan would induce bypass of air intended for thebundles
Depending upon the minimum design ambient-air temperature the typeof turbine and the type of plant operation it may be economic to providea steam-bypass heating system for cold-weather startup This wouldoperate directly off the boiler requiring both a steam pressure-reducingstation and a de-superheating station with steam flow exhaustingdirectly into the main steam duct Part of the condenser heating steamduring startup would be supplied by the turbine exhaust and theremainder from this bypass system Alternatively large steam-isolatingvalves can be installed to supply condenser sections sequentially withsteam flows only from the turbine exhaust
The equipment extracting non condensables from the systemconsists of the hogging ejector and the operating ejectors Duringstartup the hogging ejector removes air from inside the turbinesteam ducts steam manifolds and bundles It reduces the airpressure within the system front atmospheric to about 10 in Hgabsolute in a time period
For the usual full-vacuum steam condenser a two-stage operatingejector system complete with condensers is normally provided with orwithout standby Its capacity is generally specified by the purchaser inaccord with the Heat Exchange Institute Standards for steam surfacecondensers Some purchasers add a safety allowance by doubling theventing capacity recommended in the standard Thc costliest parts of theejector package arc the inter- and after-condensers which are shell-and-tube construction These can be smaller and lower-cost if a separatecolder cooling-water supply is used instead of the hot condensate
Motor-operated vacuum pumps can also be chosen these adaptreadily to automated remote operations The purchasers inquiryspecification should establish for the air removal package thesepoints choice ofsteam-jet air ejector or motor-driven vacuum pump motive steampressure and temperature hogging-ejector minimum operating time evacuating capacity of operating ejectorpackage (compared with Standards recommendation) standby
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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2 Revised 0606
Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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2 Revised 0606
How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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2 Revised 0606
accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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2 Revised 0606
GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
8112019 Dry Cooling Systems12
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
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be given to variable-pitch fans air-flow control louvers steam isolatingvalves and two-speed motors The extra price of electric starters neededfor two-speed motors should be included
Wind walls are sometimes necessary to protect the bundles from windgusts that can upset equilibrium operating conditions and at times causefreezing in some remote parts of the tower Partition walls between fancells isolate operating cells from non operating ones Without partitionwalls a non operating fan would induce bypass of air intended for thebundles
Depending upon the minimum design ambient-air temperature the typeof turbine and the type of plant operation it may be economic to providea steam-bypass heating system for cold-weather startup This wouldoperate directly off the boiler requiring both a steam pressure-reducingstation and a de-superheating station with steam flow exhaustingdirectly into the main steam duct Part of the condenser heating steamduring startup would be supplied by the turbine exhaust and theremainder from this bypass system Alternatively large steam-isolatingvalves can be installed to supply condenser sections sequentially withsteam flows only from the turbine exhaust
The equipment extracting non condensables from the systemconsists of the hogging ejector and the operating ejectors Duringstartup the hogging ejector removes air from inside the turbinesteam ducts steam manifolds and bundles It reduces the airpressure within the system front atmospheric to about 10 in Hgabsolute in a time period
For the usual full-vacuum steam condenser a two-stage operatingejector system complete with condensers is normally provided with orwithout standby Its capacity is generally specified by the purchaser inaccord with the Heat Exchange Institute Standards for steam surfacecondensers Some purchasers add a safety allowance by doubling theventing capacity recommended in the standard Thc costliest parts of theejector package arc the inter- and after-condensers which are shell-and-tube construction These can be smaller and lower-cost if a separatecolder cooling-water supply is used instead of the hot condensate
Motor-operated vacuum pumps can also be chosen these adaptreadily to automated remote operations The purchasers inquiryspecification should establish for the air removal package thesepoints choice ofsteam-jet air ejector or motor-driven vacuum pump motive steampressure and temperature hogging-ejector minimum operating time evacuating capacity of operating ejectorpackage (compared with Standards recommendation) standby
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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2 Revised 0606
Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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2 Revised 0606
accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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2 Revised 0606
GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
8112019 Dry Cooling Systems12
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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2 Revised 0606
Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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2 Revised 0606
How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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2 Revised 0606
accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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2 Revised 0606
The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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2 Revised 0606
GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
8112019 Dry Cooling Systems12
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33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
8112019 Dry Cooling Systems12
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
8112019 Dry Cooling Systems12
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8112019 Dry Cooling Systems12
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
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maximize the turbines thermal efficiency and power output minimize theauxiliary-fan power consumption and protect the condenser fromfreezing
In the event of complete electric-power failure to the steam-condenserfans an atmospheric-relief diaphragm safety device should beinstalled in the turbine exhaust system to protect the turbine exhausthood from excessive steam pressure This diaphragm generallyruptures and relieves at about 5 psi for turbines designed for full-vacuum service Some turbine manufacturers provide such a deviceon the exhaust hood if not the purchaser can provide externalprotection by installing an atmospheric relief valve(s) in the exhauststeam duct close to the turbine
The large steam duct connecting the turbine exhaust to the steam-condenser manifold condenses a considerable quantity of steam duringa cold startup while the metal temperature rises to some equilibriumlevel This condensate must be drained to an appropriate low point inthe duct system and then pumped or ejected into the condensatestorage tank
Pumping systems account for nearly 20 of the worldrsquos electrical energydemand and range from 25-50 of the energy usage in certain industrialplant operations (US DOE 2004)
Pumps have two main purposesƒ Transfer of liquid from one place to another place (eg water froman underground
aquifer into a water storage tank)ƒ Circulate liquid around a system (eg cooling water or lubricantsthrough machines and
equipment)
2 Pumping systemcharacteristics
121 Resistance of thesystem head Pressure is needed to pump the liquid through the system at a certainrate This pressure has to be high enough to overcome the resistance ofthe system which is also called ldquoheadrdquo The total head is the sum ofstatic head and friction head
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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2 Revised 0606
Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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2 Revised 0606
How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
8112019 Dry Cooling Systems12
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2 Revised 0606
accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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2 Revised 0606
The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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2 Revised 0606
available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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2 Revised 0606
GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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2 Revised 0606
changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
8112019 Dry Cooling Systems12
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33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
8112019 Dry Cooling Systems12
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
8112019 Dry Cooling Systems12
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8112019 Dry Cooling Systems12
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
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a)Statichead Static head is the difference in height between the source anddestination of the pumped liquid (see Figure 2a) Static head isindependent of flow (see Figure 2b) The static head at a certainpressure depends on the weight of the liquid and can be calculated withthis equation
Head (in feet) = Pressure (psi) X 231Specific gravity
Static head consists ofƒ Static suction head (hS) resulting from lifting the liquid relative to thepump center line
The hS is positive if the liquid level is above pump centerline andnegative if the liquid level is below pump centerline (also calledldquosuction lift)
ƒ Static discharge head (hd) the vertical distance between the pumpcenterline and the
surface of the liquid in the destination tank
b) Friction head(hf)This is the loss needed to overcome that is caused by the resistance toflow in the pipe and fittings It is dependent on size condition and type ofpipe number and type of pipe fittings flow rate and nature of the liquidThe friction head is proportional to the square of the flow rate as shownin figure 3 A closed loop circulating system only exhibits friction head(ie not static head)
4 Pump suction performance(NPSH) Cavitation or vaporization is the formation of bubbles inside the pumpThis may occur when at the fluidrsquos local static pressure becomes lowerthan the liquidrsquos vapor pressure (at the actual temperature) A possiblecause is when the fluid accelerates in a control valve or around apump impeller
Vaporization itself does not cause any damage However when thevelocity is decreased and pressure increased the vapor will evaporateand collapse This has three undesirable effectsƒ Erosion of vane surfaces especially when pumpingwater-based liquids
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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2 Revised 0606
Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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2 Revised 0606
How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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2 Revised 0606
accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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2 Revised 0606
The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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2 Revised 0606
available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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2 Revised 0606
GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
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2 Revised 0606
changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
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160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
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ƒ Increase of noise and vibration resulting in shorter sealand bearing lifeƒ Partially choking of the impeller passages which reduces the pumpperformance and can
lead to loss of total head in extreme cases
The Net Positive Suction Head Available (NPSHA) indicates how muchthe pump suction exceeds the liquid vapor pressure and is acharacteristic of the system design The NPSH Required (NPSHR) is thepump suction needed to avoid cavitation and is a characteristic of thepump design
TYPE OF PUMPS
This section describes the various types of pumps2 Pumps come in avariety of sizes for a wide range of applications They can be classifiedaccording to their basic operating principle as dynamic or positivedisplacement pumps (Figure 7)
Pumps
Dynamic Others
(egImpulseBuoyancy)
Positive Displacement
Centrifugal Special effect Rotary Reciprocating
Internalgear
External
gear
Lobe
Slidevane
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Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
8112019 Dry Cooling Systems12
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2 Revised 0606
How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
8112019 Dry Cooling Systems12
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2 Revised 0606
accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
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2 Revised 0606
The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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2 Revised 0606
available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
8112019 Dry Cooling Systems12
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2 Revised 0606
GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
8112019 Dry Cooling Systems12
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2 Revised 0606
changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
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32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
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33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
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160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
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2 Revised 0606
Figure 7 Different types of pumps In principle any liquid can be handled by any of the pump designs Where differentpump designs could be used the centrifugal pump is generally the most economicalfollowed by rotary and reciprocating pumps Although positive displacement pumpsare generally more efficient than centrifugal pumps the benefit of higher
efficiency tends to be offset by increased maintenance costs
Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate liquid istaken from one end and positively discharged at the other end for every revolutionPositive displacement pumps are widely used for pumping fluids other than watermostly viscous fluids
Positive displacement pumps are further classified based upon the mode ofdisplacementƒ Reciprocating pump if the displacement is by reciprocation of a pistonplunger
Reciprocating pumps are used only for pumping viscous liquids and oilwells
ƒ Rotary pumps if the displacement is by rotary action of a gear cam or vanes ina chamber
of diaphragm in a fixed casing Rotary pumps are further classified such asinternal gear external gear lobe and slide vane etc These pumps are used for
special services with particular conditions existing in industrial sites
In all positive displacement type pumps a fixed quantity of liquid is pumped aftereach revolution So if the delivery pipe is blocked the pressure rises to a very highvalue which can damage the pump2 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation a rotatingimpeller converts kinetic energy into pressure or velocity that is needed to pump the
fluid
There are two types of dynamic pumpsƒ Centrifugal pumps are the most common pumps used for pumping water inindustrial
applications Typically more than 75 of the pumps installed in an industry arecentrifugal pumps For this reason this pump is further described below
ƒ Special effect pumps are particularly used for specialized conditions at anindustrial site
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2 Revised 0606
How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
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2 Revised 0606
accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
8112019 Dry Cooling Systems12
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2 Revised 0606
The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
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2 Revised 0606
available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
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2 Revised 0606
GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3140
2 Revised 0606
changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3240
32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3340
33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3440
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3540
35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3740
APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3840
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3940
APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 4040
983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
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2 Revised 0606
How a centrifugal pump works A centrifugal pump is one of the simplest pieces of equipment in any process plantFigure 8 shows how this type of pump operatesƒ Liquid is forced into an impeller either by atmospheric pressure or in case of a
jet pumpby artificial pressure
ƒ The vanes of impeller pass kinetic energy to the liquid thereby causing theliquid to
rotate The liquid leaves the impeller at high velocityƒ The impeller is surrounded by a volute casing or in case of a turbine pump astationary
diffuser ring The volute or stationary diffuser ring converts the kinetic energy intopressure energy
Difficulties in the assessment of pumps
In practice it is more difficult to assess pump performance Some importantreasons are
ƒ Absence of pump specification data Pump specification data (see Worksheet
1 in section6) are required to assess the pump performance Most companies do not keeporiginal equipment manufacturer (OEM) documents that provide these data Inthese cases the percentage pump loading for a pump flow or head cannot beestimated satisfactorily
ƒ Difficulty in flow measurement It is difficult to measure the actual flow Themethods
are used to estimate the flow In most cases the flow rate is calculated based ontype of fluid head and pipe size etc but the calculated figure may not be
8112019 Dry Cooling Systems12
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2 Revised 0606
accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 2640
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 2740
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 2840
2 Revised 0606
The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 2940
2 Revised 0606
available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3040
2 Revised 0606
GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3140
2 Revised 0606
changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3240
32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3340
33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3440
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3540
35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3740
APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3840
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3940
APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 4040
983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
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2 Revised 0606
accurate Another method is to divide the tank volume by the time it takes for thepump to fill the tank This method can however only be applied if one pump is inoperation and if the discharge valve of the tank is closed The mostsophisticated accurate and least time consuming way to measure the pump flowis by measurement with an ultrasonic flow meter
ƒ Improper calibration of pressure gauges and measuring instruments Proper calibration
of all pressure gauges at suction and discharge lines and other power measuringinstruments is important to obtain accurate measurements But calibration has noalways been carried out Sometimes correction factors are used when gaugesand instruments are not properly calibrated Both will lead to incorrectperformance assessment of pumps
ENERGY EFFICIENCY OPPORTUNITIES
This section includes main areas for improving pumps and pumping systems Themain areas for energy conservation includeƒ Selecting the right pumpƒ Controlling the flow rate by speed variationƒ Pumps in parallel to meet varying demandƒ Eliminating flow control valveƒ Eliminating by-pass controlƒ Startstop control of pumpƒ Impeller trimming
Centifugal pumpThe centrifugal pump creates an increase in pressure by transferring me-chanical energy from the motor to the fluid through the rotating impeller Thefluid flows from the inlet to the impeller centre and out along its blades Thecentrifugal force hereby increases the fluid velocity and consequently also thekinetic energy is transformed to pressure
Centrifugal pumps basically consist of a stationary pump casing and an impellermounted on a rotating shaft The pump casing provides a pressure boundaryfor the pump and contains channels to properly direct the suction and dischargeflow The pump casing has suction and discharge penetrations for the main flowpath of the pump and normally has small drain and vent fittings to remove gasestrapped in the pump casing or to drain the pump casing for maintenance
Figure 1 is a simplified diagram of a typical centrifugal pump that shows the
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 2640
8112019 Dry Cooling Systems12
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8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 2840
2 Revised 0606
The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
8112019 Dry Cooling Systems12
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2 Revised 0606
available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
8112019 Dry Cooling Systems12
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2 Revised 0606
GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
8112019 Dry Cooling Systems12
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2 Revised 0606
changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
8112019 Dry Cooling Systems12
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32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
8112019 Dry Cooling Systems12
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33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
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35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
8112019 Dry Cooling Systems12
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APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
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8112019 Dry Cooling Systems12
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APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
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983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
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8112019 Dry Cooling Systems12
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2 Revised 0606
The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
8112019 Dry Cooling Systems12
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2 Revised 0606
available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
8112019 Dry Cooling Systems12
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2 Revised 0606
GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3140
2 Revised 0606
changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3240
32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3340
33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3440
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3540
35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3740
APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3840
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3940
APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 4040
983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 2740
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 2840
2 Revised 0606
The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 2940
2 Revised 0606
available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3040
2 Revised 0606
GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3140
2 Revised 0606
changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3240
32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3340
33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3440
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3540
35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3740
APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3840
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3940
APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 4040
983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 2840
2 Revised 0606
The comparison of both designs of horizontal pumps with the vertical expressed as
ratios
(A1A3 H3H1 etc) clearly demonstrates the general order of magnitude of the area and
height differences of the three types of pumps It should be noted that the vertical turbine
occupies even less floor area than the close coupled unit shown in Figure 1 In general then
consider the vertical where available area is critical and the horizontal where available
headroom is critical
Priming ndash Where the level of the liquid to be pumped is below the floor level no special primin
equipment is required for the vertical turbine pump since the impellers are always submergedHowever where a horizontal pump is used some method must be used to raise the water tothe impeller before the pump is started
This can be accomplished by using auxiliary vacuum pumps air aspirators or self primingpumps Foot valves can also be used so that once filled the suction pipe is kept full of liquid a
all times However the point to keep in mind is that the vertical turbine pump is always primedor submerged and thus requires no special priming equipment or special starting procedures
Net Positive Suction Head ndash In order to avoid cavitation the net positive suction head(NPSH) available must be greater than the NPSH required by the pump For a given set ofconditions the NPSH available increases as the submergence over the pump increases or ifthere is a suction hit the NPSH available increases as the lift is decreased On vertical pumps
as noted in the discussion above on priming the suction lift is eliminated and furthermore itusually is a comparatively simple matter to provide enough submergence by properly selectin
the length of vertical column and thus provide enough NPSH available to simplify the pumpselection ldquocavitation-wiserdquo In contrast to this a given a given horizontal pump has no flexibili
since the amount of suction lift or submergence is fixed by the plant layout Consequently
where extremely low NPSH is available the vertical pump is usually far easier to adapt than ahorizontal
A good example of this occurs frequently in the application of condensate pumps Hot wells
are often located close to the floor in order to reduce the over-all height and thus the cost ofthebuilding However by so doing the NPSH available with respect to the floor is minimized
Thus it is not uncommon on condensate pump applications to have only 2 or 3 feet NPSHavailable with respect to the floor It can be seen from Figure 4 that by using a vertical pumpenough submergence can be added to the 2 or 3 feet to insure cavitation-free operation
In addition to the example just discussed other common applications occur where NPSH
is critical such as pumping highly volatile fluids (propane ammonia etc) Also there areinstallations where hydraulic losses in the suction pipe leading to the pump are sufficiently
high to reduce the absolute pressure of the fluid to a point where it is one or two pounds over
the vapor pressure thus normally requiring a vertical to increase the submergence of NPSH
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 2940
2 Revised 0606
available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3040
2 Revised 0606
GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3140
2 Revised 0606
changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3240
32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3340
33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3440
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3540
35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3740
APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3840
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3940
APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 4040
983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 2940
2 Revised 0606
available
Figure 1
HORIZONTAL close coupled end
suction
Figure 2
HORIZONTAL
double suction
split case
Figure 3
VERTICAL turbine
pump
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3040
2 Revised 0606
GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3140
2 Revised 0606
changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3240
32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3340
33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3440
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3540
35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3740
APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3840
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3940
APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 4040
983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3040
2 Revised 0606
GP
Hea
Motor
Motor
Fig 1 Fig 2 Fig 3 Area Height
10 13 5 3460
3460
3460
3460
1760
1760
176
0 1760
1760
1760
2550
3138
3550
3675
1100
1588
1588
1650
281
4
97
564
606
875
869
1288
1388
4150
4612
5144
5144
6712
6712
81
25 8125
9850
9700
1650
2000
2100
2100
2900
2900
35
25 3525
4350
4400
685
922
1080
1080
1945
1945
28
60 2860
4280
4275
1788
1900
2100
2100
2850
3100
33
33 3488
3862
4300
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
1250
1900
1900
2100
2100
2300
31
00 3100
3100
3800
156
361
361
441
441
529
96
1 961
961
1444
2738
3619
4244
4244
5062
5775
65
75 7250
7250
7725
18
14
16
14
44
26
30
25
44
37
30
30
45
30
31
42
33
31
1
1
2
2
1
1
2
21
1
1
15
25
1 30
20
2 50
0 160
25
1000
160
50
1500
160
75
2000
160
100
2500
190
150
3000
210
200
3500
225
250
Note L W amp H are expressed in inches H = Over-all Height A = Total Floor Area of
Base
Expressed in square inches
Flexibility ndash Where changes in pumping heads are anticipated because of plant expansion
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3140
2 Revised 0606
changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3240
32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3340
33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3440
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3540
35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3740
APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3840
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3940
APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 4040
983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3140
2 Revised 0606
changes in a process or transfer of the pump to a different service it is relatively easy andinexpensive to add or remove stages from a vertical turbine type pump in order to meet thenew conditions Many users recognize the limitation of the horizontal type of pump in thisrespect and partially compensate for this shortcoming by specifying on new equipment thatfull diameter and minimum diameter impellers are not acceptable It should be recognized thatthis practice can sometimes mean that the manufacturer to avoid using a full diameterimpeller is forced to select a pump larger than necessary to meet the initial conditions and in
some cases less efficient pump
Thus both initial and operating costs are increased in some cases in order to have a unitwhich is capable of an increase in head by substituting a full or larger diameter impeller if andwhen the need arises Vertical turbine pumps however can be staged and de-staged
relatively easily Where increased heads are anticipated the vertical turbine can be built sothat additional stages can be added in the future often with little
expense compared with the initial cost of the unit This usually means furnishing the pump
initially with sufficiently large shafting and motor base to accommodate the increased future
horsepower Where the head is decreased it is a simple matter to de-stage the bowl unit
Corrosion and Abrasion ndash The high cost of repair and down time on many pumps which are
applied on corrosive andor abrasive applications is well known to operating personnel On
vertical turbine pumps the bearings are lubricated by the fluidbeing pumped This is a distinct disadvantage when compared with horizontal centrifugalunits where the pump bearings are usually if not always oil or grease lubricated and arecompletelyisolated from the fluid being pumped
It is true that vertical turbine process pumps have been successfully applied for corrosivefluids by using special bearing materials such as TFE graphitar boron carbide Babbitt andmeehanite It is also true that in severe abrasive service the bearings can be flushed by aclean non-corrosive fluid provided the process fluid will not be contaminated by the flushingfluid Such a designis shown in Figure 5 However use of special
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3240
32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3340
33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3440
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3540
35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3740
APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3840
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3940
APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 4040
983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3240
32 Revised
Figure 6 Typical horizontal process pump
Figure 5 Vertical
Pump bowldesigned for useof special flushing fluid
bearing lubrication or materials means special non-standard equipment with relatively high
initial costs and longer delivery Therefore where other considerations are equal the
horizontal pump ldquobearing-wise has a distinct advantage over the vertical turbine where
severe abrasion andor corrosion is to be expected
Figure 6 pictures a horizontal-type process pump Note the entire bearing bracket isisolated from the fluid being pumped by means of the backplate
This type of design means that only the shaft volute impeller and backplate need be
made of corrosion bracket usually made of inexpensive material such as cast iron In
contrast to this all parts of the vertical turbine are exposed to the fluidand consequently must be made of suitable material throughout in order to resist corrosiveattack Thus in addition to the bearing problem a vertical turbine process pump made out of
high alloy materials is considerably more expensive than a horizontal process pump madewith the same high alloy and designed for the same service
Inspection and Repair ndash In general the horizontal pump is far more accessible forinspection maintenance and repair than the vertical turbine pump There are
undoubtedly exceptions to this plus the fact that ease of maintenance of various types of
horizontals will vary considerably However to inspect a turbine pump bowl the motormotor base and column all must be removed before the bowl can be disconnected from
the column to which it is attached In contrast to this for example is the double suction
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3340
33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3440
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3540
35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3740
APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3840
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3940
APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 4040
983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3340
33 Revised
horizontally split horizontal pump Figure 7 pictures such a pump With the upper half of
the case removed thus allowing the complete rotating unit to be visually inspected and
removedif necessary Neither the piping nor the motor need be disturbed to remove the rotatingelement There are also vertically split horizontal pumps designed so that it is unnecessary to
disturb the motoror piping in order to remove the rotating assembly
Conclusions ndash Besides the characteristics of the pump itself there are certainly other factors
which influence the choice of pumping equipment not the least of which is the design and
configuration of the plant equipment and layout with which the pump must be coordinated
Other factors such assafety regulations will affect the choice of pumping equipment For example in order to avoidside outlets in the storage tank it is normally goodsafety practice on above ground tanks to use vertical we pit pumps when pumpingoleum
But even where well defined factors such as these do not pre-determine the choice of
pump types it is a mistake to make any hard and fast rules about the selection of a horizonta
over a vertical or vice versa Often in marginal cases where new equipment is being
considered it would be expedient to obtain quotations on both horizontal and vertical typesEach application must be judged on its won merits keeping in mind the basic advantages an
disadvantages of each type as outlined above
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3440
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3540
35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3740
APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3840
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3940
APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 4040
983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3440
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3540
35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3740
APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3840
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3940
APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 4040
983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3540
35 Revised
OPTION CHECKLIST
This section includes most important options to improve energy efficiency ofpumps and pumping systems
ƒ Operate pumps near their best efficiency point (BEP)
ƒ Ensure adequate NPSH at site of installation
ƒ Modify pumping system and pumps losses to minimize throttling
ƒ Ensure availability of basic instruments at pumps like pressure gauges flowmeters
ƒ Adapt to wide load variation with variable speed drives or sequencedcontrol of multiple units
ƒ Avoid operating more than one pump for the same application
ƒ Use booster pumps for small loads requiring higher pressures
ƒ To improve the performance of heat exchangers reduce the difference intemperature between the inlet and outlet rather than increasing the flowrate
ƒ Repair seals and packing to minimize water loss by dripping
ƒ Balance the system to minimize flows and reduce pump power requirements
ƒ Avoid pumping head with a free-fall return (gravity) and use the siphon effect
ƒ Conduct a water balance to minimize water consumption thusoptimum pump operation
ƒ Avoid cooling water re-circulation in DG sets air compressorsrefrigeration systems cooling towers feed water pumps condenser pumps
and process pumpsƒ In multiple pump operations carefully combine the operation of pumps
to avoid throttling
ƒ Replace old pumps with energy efficient pumps
ƒ T improve the efficiency of oversized pumps install variable speed drivedownsize
replace impeller or replace with a smallerpump
ƒ Optimize the number of stages in multi-stage pump if margins in pressure exist
ƒ Reduce the system resistance by pressure drop assessment and pipe sizeoptimizationƒ Regularly check for vibration to predict bearing damage misalignments
unbalance foundation looseness etc
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3740
APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3840
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3940
APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 4040
983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3640RequiredDischarge =
160M3hr
RequiredHead=160M
As per selection minimum motor power required
140kw but as per Nema it is come in 160kw
Efficiency = 64
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3740
APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3840
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3940
APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 4040
983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3740
APEX PUMPS
35
Apex GC pumpsets Outline dimensions
For
indication
onlyCertified
drawingsavailable on
request
All dimensions mm
PUMP MOTOR FLANGES PUMP DIMENSIONS FOOT
DIMENSIONS PLUGS MOTOR MODEL FRAME IN OUT Ls Ld
H0 H1 H2 W1 W2 N1 N2 M1 M2 S G1 G2G3 Lm AD KG
40-125 0752 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 36
40-125 112 N80 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 255 129 37
40-125 152 A90S 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 244 148 40
40-125 222 A90L 40 40 150 150 5 150 167 120 108 270
230 180 140 14 14 14 14 269 148 43
50-160 152 A90S 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 244 148 48
50-160 222 A90L 50 50 190 190 5 155 165 130 125 270
230 180 140 14 14 14 14 269 148 51
50-160 302 A100L 50 50 190 190 5 155 165 130 125
270 230 180 140 14 14 14 14 303 155 58
50-160 402 A112M 50 50 190 190 5 155 165 130 125
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3840
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3940
APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 4040
983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3840
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3940
APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 4040
983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 3940
APEX PUMPS
37
Apex GC pumpsets Outline dimensions
270 230 180 140 14 14 14 14 517 250 154
65-250 1852 A160L 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 517 250 170
65-250 222 A180M 65 65 260 260 5 170 210 180 180
270 230 180 140 14 14 14 14 578 291 192
65-160A 552 A132S 65 65 220 220 5 175 166 150 135270 230 180 140 14 14 14 14 405 193 88
65-160A 752 A132S 65 65 220 220 5 175 166 150 135
270 230 180 140 14 14 14 14 405 193 94
65-160A 112 A160M 65 65 220 220 5 175 206 150 135
270 230 180 140 14 14 14 14 517 250 113
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 4040
983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160
8112019 Dry Cooling Systems12
httpslidepdfcomreaderfulldry-cooling-systems12 4040
983124983151983156983137983148 983152983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150 983137983155 983152983141983154 983152983151983159983141983154 983152983148983137983150983156 983139983151983150983140983141983150983155983151983154
983123983118983151
983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150
983141983153983157983145983152983149983141983150983156 983125983150983145983156 983108983137983156983137983155
1 983110983137983150 983117983151983156983151983154 983115983159 501
2 983107983109983120 983117983151983156983151983154(983107983109983120)(983142983151983154 983151983150983141 983152983157983149983152) 983115983159 7735
3 983112983151983156983159983141983148983148 983117983151983156983151983154(983112983127983124)(983142983151983154 983151983150983141 983152 983115983159 215
983124983151983156983137983148 5805
1 983124983161983152983141
2 983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
3 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107
4 983121983156983161 983122983141983157983145983154983141983140 983118983151983155
983107983151983149983152983137983154983155983145983151983150 983151983142 983144983151983154983145983162983151983156983137983148 983158983155 983158983141983154983156983145983139983137983148983155 983152983157983149983152983155(983107983141983152+983112983127983124)
983112983151983154983145983162983151983156983137983148 983126983141983154983145983156983139983137983148
1 983124983161983152983141 983107983109983120 983107983109983120
2 983117983137983147983141 983123983157983148983162983141983154 983111983154983157983150983140983142983151983155
3 983120983157983149983152 983117983151983140983141983148 983130983109 1009830854400 983107983122 649830857
4 983121983157983137983150983156983145983161 1 3
5
983108983145983155983139983144983137983154983143983141 983139983137983152983137983139983145983156983161 9831493983144983154
190
643 983152983141983154 983152983157983149983152 ( 3 983118983151983155983128
643 983101193)
6 983112983141983137983140 983140983141983158983141983148983151983152983141983140 983149983127983107 160 163
7 983120983157983149983152 983145983150983152983157983156 983152983151983159983141983154 983147983127 160 45(3 983118983151983155 983128 45983101135)
8983124983151983156983137983148 983120983151983159983141983154 983139983151983150983155983157983149983152983137983156983145983151983150(3
983118983151983155)
983147983127160 135
1
983108983137983156983137 983137983155 983152983141983154 983144983151983154983145983162983151983156983137983148
983152983157983149983152 983154983141983153983157983145983154983141983149983141983150983156
983107983109983120
190
160