industrial training doc

7/30/2019 Industrial Training Doc.

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INTRODUCTIONINTRODUCTION

Satpura Thermal Power Station has an installed capacity of 1142.50 MW. TheSatpura Thermal Power Station has an installed capacity of 1142.50 MW. TheFirst unit was commissioned in October 1967. The Water for the plant hasFirst unit was commissioned in October 1967. The Water for the plant hasbeen procured from nearby Tawa Dam Lake area, which spread in 2,893been procured from nearby Tawa Dam Lake area, which spread in 2,893

acres (11.71acres (11.71 kmkm22

). The coal for the plant has been procured by Rail/Road/Belt). The coal for the plant has been procured by Rail/Road/Beltfrom Western Coal Fields. There are two more units of 250 MW are in makingfrom Western Coal Fields. There are two more units of 250 MW are in makingprocess. It will be complete in 2012-2013. There is another praposal thatprocess. It will be complete in 2012-2013. There is another praposal thatafter complition of two new units they will be install a new unit of 600 MW.after complition of two new units they will be install a new unit of 600 MW. Instead of 5 units of 62.5 MW. The construction of the extension unit 10 andInstead of 5 units of 62.5 MW. The construction of the extension unit 10 and11 are in almost last stage. SatpuraThermal Power Station is an oldest11 are in almost last stage. SatpuraThermal Power Station is an oldestrunning plant in India. The 1running plant in India. The 1stst installed unit (62.5 MW) completed its 44 yearsinstalled unit (62.5 MW) completed its 44 yearsin the month of Oct.11. The units are running with their full efficiency roundin the month of Oct.11. The units are running with their full efficiency round the year. Many times these units are awarded for meritorious productivity bythe year. Many times these units are awarded for meritorious productivity byCEA (CEA (Central Electricity AuthorityCentral Electricity Authority). The per day coal consumption of these). The per day coal consumption of theseunits is 22 thousand MT. The geographical area is surrounded by Satpuraunits is 22 thousand MT. The geographical area is surrounded by Satpura

ranges.ranges.

OVERVIEWOVERVIEW


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Satpura Thermal PowerSatpura Thermal PowerStation,SarniStation,Sarni

LOCATION

CAPACITY

SOURCE OF WATER

FUEL

COAL SOURCE

COAL AREA

MODE OF TRANSPORT

COAL LINKAGE

POWER EVACUATION

400 K.V. LINES

220 K.V. LINES

INSTALLED CAPACITYINSTALLED CAPACITYUNITS

CAPACITY MW

COMMISSIONING

DATES

MAKE TG SET

MAKE BOILER

Unit I

62.5

06-10-1967

GE USA

B&W
http://mppgenco.nic.in/stps-sarni.htmhttp://mppgenco.nic.in/stps-sarni.htmhttp://mppgenco.nic.in/stps-sarni.htmhttp://mppgenco.nic.in/stps-sarni.htmhttp://mppgenco.nic.in/stps-sarni.htmhttp://mppgenco.nic.in/stps-sarni.htmhttp://mppgenco.nic.in/stps-sarni.htm


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Unit II

62.5

21-03-1968

GE USA

B&W

Unit III

62.5

14-05-1968

GE USA

B&W

Unit IV

62.5

10-07-1968

GE USA

B&W

Unit V

62.5

17-04-1970

GE USA

B&W

Unit VI

200

01-07-1979

BHEL

BHEL

Unit VII

210

20-09-1980


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BHEL

BHEL

Unit VIII

210

25-01-1983

BHEL

BHEL

Unit IX

210

07-02-1984

BHEL

BHEL

WORKING PRINCIPLEWORKING PRINCIPLE

The Rankine cycle is the most common of all power generationThe Rankine cycle is the most common of all power generationcycles and is diagrammatically depicted via Figures 1 and 2.cycles and is diagrammatically depicted via Figures 1 and 2.The Rankine cycle was devised to make use of theThe Rankine cycle was devised to make use of thecharacteristics of water as the working fluid. The cycle beginscharacteristics of water as the working fluid. The cycle beginsin a boiler (State 4 in figure 1), where the water is heated untilin a boiler (State 4 in figure 1), where the water is heated untilit reaches saturation- in a constant-pressure process. Onceit reaches saturation- in a constant-pressure process. Oncesaturation is reached, further heat transfer takes place at asaturation is reached, further heat transfer takes place at aconstant temperature, until the working fluid reaches a qualityconstant temperature, until the working fluid reaches a qualityof 100% (State 1). At this point, the high-quality vapor isof 100% (State 1). At this point, the high-quality vapor isexpanded isoentropically through an axially bladed turbineexpanded isoentropically through an axially bladed turbinestage to produce shaft work. The steam then exits the turbinestage to produce shaft work. The steam then exits the turbineat State 2.at State 2.

The working fluid, at State 2, is at a low-pressure, but has a fairlyThe working fluid, at State 2, is at a low-pressure, but has a fairlyhigh quality, so it is routed through a condenser, where thehigh quality, so it is routed through a condenser, where thesteam is condensed into liquid (State 3). Finally, the cycle issteam is condensed into liquid (State 3). Finally, the cycle iscompleted via the return of the liquid to the boiler, which iscompleted via the return of the liquid to the boiler, which is normally accomplished by a mechanical pump. Figure 2 showsnormally accomplished by a mechanical pump. Figure 2 shows

a schematic of a power plant under a Rankine cycle.a schematic of a power plant under a Rankine cycle.


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Figure : Diagrams for a simple ideal Rankine cycle:Figure : Diagrams for a simple ideal Rankine cycle:

a) P-V diagram, b) T-S diagrama) P-V diagram, b) T-S diagram

COAL-FIRED THERMAL POWER STATIONCOAL-FIRED THERMAL POWER STATION


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In a coal based power plant coal is transported from coal mines to the powerIn a coal based power plant coal is transported from coal mines to the powerplant by railway in wagons or in a merry-go-round system. Coal is unloadedplant by railway in wagons or in a merry-go-round system. Coal is unloadedfrom the wagons to a moving underground conveyor belt. This coal from thefrom the wagons to a moving underground conveyor belt. This coal from themines is of no uniform size. So it is taken to the Crusher house and crushedmines is of no uniform size. So it is taken to the Crusher house and crushedto a size of 20mm. From the crusher house the coal is either stored in deadto a size of 20mm. From the crusher house the coal is either stored in deadstorage( generally 40 days coal supply) which serves as coal supply in casestorage( generally 40 days coal supply) which serves as coal supply in case of coal supply bottleneck or to the live storage(8 hours coal supply) in theof coal supply bottleneck or to the live storage(8 hours coal supply) in theraw coal bunker in the boiler house. Raw coal from the raw coal bunker israw coal bunker in the boiler house. Raw coal from the raw coal bunker issupplied to the Coal Mills by a Raw Coal Feeder. The Coal Mills or pulverizersupplied to the Coal Mills by a Raw Coal Feeder. The Coal Mills or pulverizer

pulverizes the coal to 200 mesh size. The powdered coal from the coal millspulverizes the coal to 200 mesh size. The powdered coal from the coal mills is carried to the boiler in coal pipes by high pressure hot air. The pulverizedis carried to the boiler in coal pipes by high pressure hot air. The pulverizedcoal air mixture is burnt in the boiler in the combustion zone.coal air mixture is burnt in the boiler in the combustion zone.

Generally in modern boilers tangential firing system is used i.e. the coalGenerally in modern boilers tangential firing system is used i.e. the coalnozzles/ guns form tangent to a circle. The temperature in fire ball is of thenozzles/ guns form tangent to a circle. The temperature in fire ball is of theorder of 1300 deg.C. The boiler is a water tube boiler hanging from the top.order of 1300 deg.C. The boiler is a water tube boiler hanging from the top.


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Water is converted to steam in the boiler and steam is separated from waterWater is converted to steam in the boiler and steam is separated from water in the boiler Drum. The saturated steam from the boiler drum is taken to thein the boiler Drum. The saturated steam from the boiler drum is taken to theLow Temperature Superheater, Platen Superheater and Final SuperheaterLow Temperature Superheater, Platen Superheater and Final Superheaterrespectively for superheating. The superheated steam from the finalrespectively for superheating. The superheated steam from the finalsuperheater is taken to the High Pressure Steam Turbine (HPT). In the HPTsuperheater is taken to the High Pressure Steam Turbine (HPT). In the HPT

the steam pressure is utilized to rotate the turbine and the resultant isthe steam pressure is utilized to rotate the turbine and the resultant isrotational energy. From the HPT the out coming steam is taken to therotational energy. From the HPT the out coming steam is taken to theReheater in the boiler to increase its temperature as the steam becomes wetReheater in the boiler to increase its temperature as the steam becomes wetat the HPT outlet. After reheating this steam is taken to the Intermediateat the HPT outlet. After reheating this steam is taken to the IntermediatePressure Turbine (IPT) and then to the Low Pressure Turbine (LPT). The outletPressure Turbine (IPT) and then to the Low Pressure Turbine (LPT). The outletof the LPT is sent to the condenser for condensing back ater by a coolingof the LPT is sent to the condenser for condensing back ater by a cooling water system. This condensed water is collected in the Hotwell and is againwater system. This condensed water is collected in the Hotwell and is again sent to the boiler in a closed cycle. The rotational energy imparted to thesent to the boiler in a closed cycle. The rotational energy imparted to theturbine by high pressure steam is converted to electrical energy in theturbine by high pressure steam is converted to electrical energy in theGenerator.Generator.

FACTOR CONSIDERED REGARDING SITE SELECTIONFACTOR CONSIDERED REGARDING SITE SELECTION

AVAILABILITY OF LANDAVAILABILITY OF LAND- the average land requirement for thermalthe average land requirement for thermal

power plant is about 3-5 acre per MW capacity. The total landpower plant is about 3-5 acre per MW capacity. The total landrequirement consists for coal storage, ash disposel, staff colony,requirement consists for coal storage, ash disposel, staff colony,market facility and space for plant machinery. As cost of land affectsmarket facility and space for plant machinery. As cost of land affectsthe capital cost of the plant, therefore it should be economical.the capital cost of the plant, therefore it should be economical.

AVAILABILITY OF COALAVAILABILITY OF COAL- 400 MW capacity require 5000-6000 tonnes400 MW capacity require 5000-6000 tonnesof coal per day. Thus a thermal power plant should be situated nearof coal per day. Thus a thermal power plant should be situated near coal mines or at sites where huge quantities of coal can be transportedcoal mines or at sites where huge quantities of coal can be transported economically, either by railways or sea routeseconomically, either by railways or sea routes..

AVAILABILITY OF WATERAVAILABILITY OF WATER- a thermal power plant needsa thermal power plant needs largelarge

quantity of water for condenser, ash disposel, feed water to the boilerquantity of water for condenser, ash disposel, feed water to the boilerand drinking water for the working staff. A plant of 60 MW capacityand drinking water for the working staff. A plant of 60 MW capacity

require 20-30 thousand tonnes of water per hour, additional 500-600require 20-30 thousand tonnes of water per hour, additional 500-600tonnes of water per hour is required if cooling tower are used. A largetonnes of water per hour is required if cooling tower are used. A large quantity of water is also required for ash disposal. The availability ofquantity of water is also required for ash disposal. The availability ofdrinking water is also equally important. It is therefore, necessary todrinking water is also equally important. It is therefore, necessary tolocate the power plant near the water source which will be able tolocate the power plant near the water source which will be able tosupply the required quantity of water for whole year.supply the required quantity of water for whole year.

ASH DISPOSAL FACILITYASH DISPOSAL FACILITY- in a largein a large plant ash percentage is 20 toplant ash percentage is 20 to40% of coal burnt this large amount of ash create big problem. The40% of coal burnt this large amount of ash create big problem. The


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ash handling problem is more serious than coal handling because itash handling problem is more serious than coal handling because it comes out in hot condition and highly corrosive.comes out in hot condition and highly corrosive.the disposal of large quantities of ash is big problem. The ash can bethe disposal of large quantities of ash is big problem. The ash can be disposed off to dam of water mixed ash.disposed off to dam of water mixed ash.

LABOUR AVAILABILITYLABOUR AVAILABILITY-- cheap and enough labour should becheap and enough labour should beavailable near the site.available near the site.

TRANSPORTATION FACILITIESTRANSPORTATION FACILITIES- itit is always essential to have railwayis always essential to have railwayline near the plant for easy transportation of heavy machinery andline near the plant for easy transportation of heavy machinery and coal.coal.

SIZE OF THE PLANTSIZE OF THE PLANT-- for smallfor small capacity plants supply of fuel andcapacity plants supply of fuel andwater are not big problem. The only consideration in such case iswater are not big problem. The only consideration in such case isminimum cost of transmission lines, thus plant should be located nearminimum cost of transmission lines, thus plant should be located near the load centre.the load centre.In large capacity plants, the cost of transporting enormous quantitiesIn large capacity plants, the cost of transporting enormous quantities

of coal and water are considerably high. Therefore, plant must beof coal and water are considerably high. Therefore, plant must belocated near the coal mines provided the required quantity of waterlocated near the coal mines provided the required quantity of watershould be available as nearly as possible.should be available as nearly as possible.

PUBLIC PROBLEMSPUBLIC PROBLEMS- the thermal power plant should be far away fromthe thermal power plant should be far away fromthe town to avoid the nuisance from the smoke, flyash and heatthe town to avoid the nuisance from the smoke, flyash and heatdischarged from power plant.discharged from power plant.

COMPONENTS OF SATPURA THERMAL POWER STATIONCOMPONENTS OF SATPURA THERMAL POWER STATION cooling towercooling tower cooling water pumpcooling water pump electric generatorelectric generator

low pressure turbinelow pressure turbine

boiler feed pumpboiler feed pump condensercondenser intermediate pressure turbineintermediate pressure turbine steam governor valvesteam governor valve high pressure turbinehigh pressure turbine deaeratordeaerator feed heaterfeed heater


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coal conveyorcoal conveyor coal hoppercoal hopper pulverized fuel millpulverized fuel mill boiler drumboiler drum ash hopperash hopper

superheatedsuperheated forced draught fanforced draught fan repeaterrepeater air intakeair intake economizereconomizer air preheaterair preheater electrostatic precipitatorelectrostatic precipitator induced draught faninduced draught fan chimney stackchimney stack

COOLING TOWERCOOLING TOWER- The condensate (water) formed in the condeserThe condensate (water) formed in the condeser

after condensation is initially at high temperature.This hot water isafter condensation is initially at high temperature.This hot water ispassed to cooling towers.It is a tower- or building-like device in whichpassed to cooling towers.It is a tower- or building-like device in whichatmospheric air (the heat receiver) circulates in direct or indirectatmospheric air (the heat receiver) circulates in direct or indirectcontact with warmer water (the heat source) and the water is therebycontact with warmer water (the heat source) and the water is therebycooled (see illustration). A cooling tower may serve as the heat sink incooled (see illustration). A cooling tower may serve as the heat sink ina conventional thermodynamic process, such as refrigeration or steama conventional thermodynamic process, such as refrigeration or steampower generation, and when it is convenient or desirable to make finalpower generation, and when it is convenient or desirable to make final heat rejection to atmospheric air. Water, acting as the heat-transferheat rejection to atmospheric air. Water, acting as the heat-transferfluid, gives up heat to atmospheric air, and thus cooled, is recirculatedfluid, gives up heat to atmospheric air, and thus cooled, is recirculatedthrough the system, affording economical operation of the process.through the system, affording economical operation of the process.

Two basic types of cooling towers are commonly used. One transfersTwo basic types of cooling towers are commonly used. One transfersthe heat from warmer water to cooler air mainly by an evaporationthe heat from warmer water to cooler air mainly by an evaporation heat-transfer process and is known as the evaporative or wet coolingheat-transfer process and is known as the evaporative or wet coolingtower.tower.

Evaporative cooling towers are classified according to the meansEvaporative cooling towers are classified according to the means

employed for producing air circulation through them: atmospheric,employed for producing air circulation through them: atmospheric,natural draft, and mechanical draft. The other transfers the heat fromnatural draft, and mechanical draft. The other transfers the heat from


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warmer water to cooler air by a sensible heat-transfer process and iswarmer water to cooler air by a sensible heat-transfer process and is known as the nonevaporative or dry cooling tower.known as the nonevaporative or dry cooling tower.

Nonevaporative cooling towers are classified as air-cooled condensersNonevaporative cooling towers are classified as air-cooled condensersand as air-cooled heat exchangers, and are further classified by theand as air-cooled heat exchangers, and are further classified by the

means used for producing air circulation through them. These twomeans used for producing air circulation through them. These twobasic types are sometimes combined, with the two cooling processesbasic types are sometimes combined, with the two cooling processesgenerally used in parallel or separately, and are then known as wet-drygenerally used in parallel or separately, and are then known as wet-drycooling towers.cooling towers.

GENERATORGENERATOR- Generator or Alternator is the electrical end of aGenerator or Alternator is the electrical end of aturbo-generator set. It is generally known as the piece of equipmentturbo-generator set. It is generally known as the piece of equipmentthat converts the mechanical energy of turbine into electricity. Thethat converts the mechanical energy of turbine into electricity. Thegeneration of electricity is based on the principle of electromagneticgeneration of electricity is based on the principle of electromagneticinduction.induction.

TURBINETURBINE- Steam turbines have been used predominantly as primeSteam turbines have been used predominantly as primemover in all thermal power stations. The steam turbines are mainlymover in all thermal power stations. The steam turbines are mainlydivided into two groups: -divided into two groups: -

1. Impulse turbineImpulse turbine

2. Impulse-reaction turbineImpulse-reaction turbine

The turbine generator consists of a series ofThe turbine generator consists of a series ofsteamsteam turbinesturbines interconnected to each other and a generator on ainterconnected to each other and a generator on acommon shaft. There is a high pressure turbine at one end, followed bycommon shaft. There is a high pressure turbine at one end, followed byan intermediate pressure turbine, two low pressure turbines, and thean intermediate pressure turbine, two low pressure turbines, and the generator.generator. The steam at high temperature (536 c to 540 c) andThe steam at high temperature (536 c to 540 c) andpressure (140 to 170 kg/cm2) is expanded in the turbine.pressure (140 to 170 kg/cm2) is expanded in the turbine.

Turbine used here are categorized as followsTurbine used here are categorized as follows1. Low pressure turbineLow pressure turbine


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2. Intermediate presuure turbineIntermediate presuure turbine3. High pressure turbineHigh pressure turbine

BOILER FEED PUMPBOILER FEED PUMP-- Boiler feed pump is a multi stage pumpBoiler feed pump is a multi stage pump

provided for pumping feed water to economiser. BFP is the biggestprovided for pumping feed water to economiser. BFP is the biggestauxiliary equipment after Boiler and Turbine. It consumes about 4 to 5auxiliary equipment after Boiler and Turbine. It consumes about 4 to 5 % of total electricity generation.% of total electricity generation.

CONDENSERCONDENSER- Steam after rotating staem turbine comes toSteam after rotating staem turbine comes tocondenser.Condenser refers here to the shell and tube heat exchangercondenser.Condenser refers here to the shell and tube heat exchanger (or surface condenser) installed at the outlet of every steam turbine in(or surface condenser) installed at the outlet of every steam turbine inThermal power stations of utility companies generally. TheseThermal power stations of utility companies generally. Thesecondensers are heat exchangers which convert steam from its gaseouscondensers are heat exchangers which convert steam from its gaseousto its liquid state, also known as phase transition. In so doing, theto its liquid state, also known as phase transition. In so doing, the latent heat of steam is given out inside the condenser. Where water islatent heat of steam is given out inside the condenser. Where water is in short supply an air cooled condenser is often used. An air cooledin short supply an air cooled condenser is often used. An air cooledcondenser is however significantly more expensive and cannot achievecondenser is however significantly more expensive and cannot achieveas low a steam turbine backpressure (and therefore less efficient) as aas low a steam turbine backpressure (and therefore less efficient) as asurface condenser.surface condenser.The purpose is to condense the outlet (or exhaust) steam from steamThe purpose is to condense the outlet (or exhaust) steam from steamturbine to obtain maximum efficiency and also to get the condensedturbine to obtain maximum efficiency and also to get the condensedsteam in the form of pure water, otherwise known as condensate, backsteam in the form of pure water, otherwise known as condensate, backto steam generator or (boiler) as boiler feedwater.to steam generator or (boiler) as boiler feedwater.

Why it is required?Why it is required?The steam turbine itself is a device to convert the heat in steam toThe steam turbine itself is a device to convert the heat in steam tomechanical power. The difference between the heat of steam per unitmechanical power. The difference between the heat of steam per unitweight at the inlet to turbine and the heat of steam per unit weight atweight at the inlet to turbine and the heat of steam per unit weight at the outlet to turbine represents the heat given out (or heat drop) in thethe outlet to turbine represents the heat given out (or heat drop) in thesteam turbine which is converted to mechanical power. The heat dropsteam turbine which is converted to mechanical power. The heat dropper unit weight of steam is also measured by the word enthalpy drop.per unit weight of steam is also measured by the word enthalpy drop.Therefore the more the conversion of heat per pound (or kilogram) ofTherefore the more the conversion of heat per pound (or kilogram) ofsteam to mechanical power in the turbine, the better is itssteam to mechanical power in the turbine, the better is itsperformance or otherwise known as efficiency. By condensing theperformance or otherwise known as efficiency. By condensing the


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exhaust steam of turbine, the exhaust pressure is brought down belowexhaust steam of turbine, the exhaust pressure is brought down belowatmospheric pressure from above atmospheric pressure, increasing theatmospheric pressure from above atmospheric pressure, increasing thesteam pressure drop between inlet and exhaust of steam turbine. Thissteam pressure drop between inlet and exhaust of steam turbine. Thisfurther reduction in exhaust pressure gives out more heat per unitfurther reduction in exhaust pressure gives out more heat per unitweight of steam input to the steam turbine, for conversion toweight of steam input to the steam turbine, for conversion to

mechanical power. Most of the heat liberated due to condensing, i.e.,mechanical power. Most of the heat liberated due to condensing, i.e.,latent heat of steam, is carried away by the cooling medium. (waterlatent heat of steam, is carried away by the cooling medium. (water inside tubes in a surface condenser, or droplets in a spray condenserinside tubes in a surface condenser, or droplets in a spray condenser (Heller system) or air around tubes in an air-cooled condenser).(Heller system) or air around tubes in an air-cooled condenser).

Condensers are classified as (i) Jet condensers or contact condensersCondensers are classified as (i) Jet condensers or contact condensers (ii) Surface condensers.(ii) Surface condensers.in jet condensers the steam to be condensed mixes with the coolingin jet condensers the steam to be condensed mixes with the coolingwater and the temperature of the condensate and the cooling water iswater and the temperature of the condensate and the cooling water issame when leaving the condenser; and the condensate can't besame when leaving the condenser; and the condensate can't berecovered for use as feed water to the boiler; heat transfer is by directrecovered for use as feed water to the boiler; heat transfer is by direct

conduction.conduction.In surface condensers there is no direct contact between the steam toIn surface condensers there is no direct contact between the steam tobe condensed and the circulating cooling water. There is a wallbe condensed and the circulating cooling water. There is a wallinterposed between them through heat must be convectivelyinterposed between them through heat must be convectivelytransferred.The temperature of the condensate may be higher than thetransferred.The temperature of the condensate may be higher than thetemperature of the cooling water at outlet and the condnsate istemperature of the cooling water at outlet and the condnsate isrecovered as feed water to the boiler.Both the cooling water and therecovered as feed water to the boiler.Both the cooling water and thecondensate are separetely with drawn.Because of this advantagecondensate are separetely with drawn.Because of this advantagesurface condensers are used in thermal power plants.Final output ofsurface condensers are used in thermal power plants.Final output ofcondenser is water at low temperature is passed to high pressure feedcondenser is water at low temperature is passed to high pressure feed water heater,it is heated and again passed as feed water to thewater heater,it is heated and again passed as feed water to the

boiler.Since we are passing water at high temperature as feed waterboiler.Since we are passing water at high temperature as feed waterthe temperature inside the boiler does not dcrease and boiler efficincythe temperature inside the boiler does not dcrease and boiler efficincyalso maintained.also maintained.

DEAERATORDEAERATOR- AA deaeratordeaerator is a device that is widely used for theis a device that is widely used for the

removal of oxygen and other dissolvedremoval of oxygen and other dissolved gasesgases from thefrom the feedwaterfeedwater totosteam-generating steam-generating boilersboilers. In particular, dissolved . In particular, dissolved oxygenoxygen in boilerin boilerfeedwaters will cause serious corrosion damage in steam systems byfeedwaters will cause serious corrosion damage in steam systems byattaching to the walls of metal piping and other metallic equipmentattaching to the walls of metal piping and other metallic equipmentand forming and forming oxidesoxides (rust). Dissolved(rust). Dissolved carbon dioxidecarbon dioxide combines withcombines withwater to formwater to form carbonic acidcarbonic acid that causes further corrosion. Mostthat causes further corrosion. Mostdeaerators are designed to remove oxygen down to levels of 7deaerators are designed to remove oxygen down to levels of 7 ppbppb bybyweight (0.005weight (0.005 cm/L) or less as well as essentially eliminating carboncm/L) or less as well as essentially eliminating carbondioxide.dioxide.

There are two basic types of deaerators, the tray-type and the spray-There are two basic types of deaerators, the tray-type and the spray-type:type:

TheThe tray-typetray-type (also called the(also called the cascade-typecascade-type) includes a vertical domed) includes a vertical domeddeaeration section mounted on top of a horizontal cylindrical vesseldeaeration section mounted on top of a horizontal cylindrical vesselwhich serves as the deaerated boiler feedwater storage tank.which serves as the deaerated boiler feedwater storage tank.
http://en.wikipedia.org/wiki/Gashttp://en.wikipedia.org/wiki/Gashttp://en.wikipedia.org/wiki/Feedwaterhttp://en.wikipedia.org/wiki/Feedwaterhttp://en.wikipedia.org/wiki/Boilerhttp://en.wikipedia.org/wiki/Boilerhttp://en.wikipedia.org/wiki/Boilerhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Oxidehttp://en.wikipedia.org/wiki/Oxidehttp://en.wikipedia.org/wiki/Oxidehttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Carbonic_acidhttp://en.wikipedia.org/wiki/Carbonic_acidhttp://en.wikipedia.org/wiki/Ppbhttp://en.wikipedia.org/wiki/Ppbhttp://en.wikipedia.org/wiki/Gashttp://en.wikipedia.org/wiki/Feedwaterhttp://en.wikipedia.org/wiki/Boilerhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Oxidehttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Carbonic_acidhttp://en.wikipedia.org/wiki/Ppb


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TheThe spray-typespray-type consists only of a horizontal (or vertical) cylindricalconsists only of a horizontal (or vertical) cylindricalvessel which serves as both the deaeration section and the boilervessel which serves as both the deaeration section and the boilerfeedwater storage tank.feedwater storage tank.

COAL CONVEYORCOAL CONVEYOR :This is a belt type of arrangement.With this coal isThis is a belt type of arrangement.With this coal istransported from coal storage place in power plant to the place near bytransported from coal storage place in power plant to the place near byboiler.boiler.

STOKERSTOKER -The coal which is brought near by boiler has to put in boilerThe coal which is brought near by boiler has to put in boilerfurnance for combustion.This stoker is a mechanical device for feedingfurnance for combustion.This stoker is a mechanical device for feedingcoal to a furnace.coal to a furnace.

PULVERIZERPULVERIZER -The coal is put in the boiler after pulverization.For thisThe coal is put in the boiler after pulverization.For thispulverizer is used.A pulverizer is a device for grinding coal forpulverizer is used.A pulverizer is a device for grinding coal forcombustion in a furnace in a powe plant.combustion in a furnace in a powe plant.Types of PulverizersTypes of Pulverizers

Ball and Tube Mill Ball millBall and Tube Mill Ball mill is a pulverizer that consists of ais a pulverizer that consists of ahorizontal rotating cylinder, up to three diameters in length, containinghorizontal rotating cylinder, up to three diameters in length, containing


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a charge of tumbling or cascading steel balls, pebbles, or rods.a charge of tumbling or cascading steel balls, pebbles, or rods.Tube mill is a revolving cylinder of up to five diameters in length usedTube mill is a revolving cylinder of up to five diameters in length usedfor fine pulverization of ore, rock, and other such materials; thefor fine pulverization of ore, rock, and other such materials; thematerial, mixed with water, is fed into the chamber from one end, andmaterial, mixed with water, is fed into the chamber from one end, andpasses out the other end as slime.passes out the other end as slime.Ring and BallRing and Ball This type consists ofThis type consists of

two rings separated by a series of large balls. The lower ring rotates,two rings separated by a series of large balls. The lower ring rotates, while the upper ring presses down on the balls via a set of spring andwhile the upper ring presses down on the balls via a set of spring andadjuster assemblies. Coal is introduced into the center or side of theadjuster assemblies. Coal is introduced into the center or side of thepulverizer (depending on the design) and is ground as the lower ringpulverizer (depending on the design) and is ground as the lower ringrotates causing the balls to orbit between the upper and lower rings.rotates causing the balls to orbit between the upper and lower rings. The coal is carried out of the mill by the flow of air moving through it.The coal is carried out of the mill by the flow of air moving through it.The size of the coal particals released from the grinding section of theThe size of the coal particals released from the grinding section of themill is determined by a classifer separator. These mills are typicallymill is determined by a classifer separator. These mills are typicallyproduced by B&W (Babcock and Wilcox).produced by B&W (Babcock and Wilcox).

BOILERBOILER- A Boiler or steam generator essentially is a container intoA Boiler or steam generator essentially is a container intowhich water can be fed and steam can be taken out at desiredwhich water can be fed and steam can be taken out at desiredpressure, temperature and flow. This calls for application of heat on thepressure, temperature and flow. This calls for application of heat on thecontainer. For that the boiler should have a facility to burn a fuel andcontainer. For that the boiler should have a facility to burn a fuel and release the heat. The functions of a boiler thus can be stated as:-release the heat. The functions of a boiler thus can be stated as:-

1. To convert chemical energy of the fuel into heat energyTo convert chemical energy of the fuel into heat energy

2. To transfer this heat energy to water for evaporation as well to steamTo transfer this heat energy to water for evaporation as well to steamfor superheating.for superheating.


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SUPERHEATERSUPERHEATER- Most of the modern boliers are having superheaterMost of the modern boliers are having superheaterand reheater arrangement. Superheater is a component of a steam-and reheater arrangement. Superheater is a component of a steam-generating unit in which steam, after it has left the boiler drum, isgenerating unit in which steam, after it has left the boiler drum, is heated above its saturation temperature. The amount of superheatheated above its saturation temperature. The amount of superheatadded to the steam is influenced by the location, arrangement, andadded to the steam is influenced by the location, arrangement, and

amount of superheater surface installed, as well as the rating of theamount of superheater surface installed, as well as the rating of theboiler. The superheater may consist of one or more stages of tubeboiler. The superheater may consist of one or more stages of tubebanks arranged to effectively transfer heat from the products ofbanks arranged to effectively transfer heat from the products ofcombustion.Superheaters are classified as convection , radiant orcombustion.Superheaters are classified as convection , radiant orcombination of thesecombination of these.

REHEATERREHEATER -Some of the heat of superheated steam is used to rotateSome of the heat of superheated steam is used to rotate the turbine where it loses some of its energy.Reheater is also steamthe turbine where it loses some of its energy.Reheater is also steamboiler component in which heat is added to this intermediate-pressureboiler component in which heat is added to this intermediate-pressuresteam, which has given up some of its energy in expansion through thesteam, which has given up some of its energy in expansion through thehigh-pressure turbine. The steam after reheating is used to rotate thehigh-pressure turbine. The steam after reheating is used to rotate the

second steam turbine (see Layout fig) where the heat is converted tosecond steam turbine (see Layout fig) where the heat is converted tomechanical energy.This mechanical energy is used to run themechanical energy.This mechanical energy is used to run thealternator, which is coupled to turbine , there by generating elecricalalternator, which is coupled to turbine , there by generating elecrical energyenergy.

ECONOMISERECONOMISER - Flue gases coming out of the boiler carry lot ofFlue gases coming out of the boiler carry lot of

heat.Function of economiser is to recover some of the heat from theheat.Function of economiser is to recover some of the heat from theheat carried away in the flue gases up the chimney and utilize forheat carried away in the flue gases up the chimney and utilize forheating the feed water to the boiler.It is placed in the passage of flueheating the feed water to the boiler.It is placed in the passage of fluegases in between the exit from the boiler and the entry to thegases in between the exit from the boiler and the entry to thechimney.The use of economiser results in saving in coal consumption ,chimney.The use of economiser results in saving in coal consumption ,increase in steaming rate and high boiler efficiency but needs extraincrease in steaming rate and high boiler efficiency but needs extrainvestment and increase in maintenance costs and floor area requiredinvestment and increase in maintenance costs and floor area requiredfor the plant.This is used in all modern plants.In this a large number offor the plant.This is used in all modern plants.In this a large number ofsmall diameter thin walled tubes are placed between two headers.Feedsmall diameter thin walled tubes are placed between two headers.Feedwater enters the tube through one header and leaves through thewater enters the tube through one header and leaves through theother.The flue gases flow out side the tubes usually in counter flow.other.The flue gases flow out side the tubes usually in counter flow.

AIR PREHEATERAIR PREHEATER :The remaining heat of flue gases is utilised by airThe remaining heat of flue gases is utilised by airpreheater.It is a device used in steam boilers to transfer heat from thepreheater.It is a device used in steam boilers to transfer heat from theflue gases to the combustion air before the air enters the furnace. Alsoflue gases to the combustion air before the air enters the furnace. Also

known as air heater; air-heating system. It is not shown in the layknown as air heater; air-heating system. It is not shown in the lay

out.But it is kept at a place near by where the air enters in to theout.But it is kept at a place near by where the air enters in to the boiler.boiler.The purpose of the air preheater is to recover the heat from the flueThe purpose of the air preheater is to recover the heat from the fluegas from the boiler to improve boiler efficiency by burning warm airgas from the boiler to improve boiler efficiency by burning warm airwhich increases combustion efficiency, and reducing useful heat lostwhich increases combustion efficiency, and reducing useful heat lostfrom the flue. As a consequence, the gases are also sent to thefrom the flue. As a consequence, the gases are also sent to thechimney or stack at a lower temperature, allowing simplified design ofchimney or stack at a lower temperature, allowing simplified design of


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the ducting and stack. It also allows control over the temperature ofthe ducting and stack. It also allows control over the temperature ofgases leaving the stack (to meet emissions regulations, forgases leaving the stack (to meet emissions regulations, forexample).After extracting heat flue gases are passed to elctrostaticexample).After extracting heat flue gases are passed to elctrostaticprecipitator.precipitator.

ELECTROSTATIC PRECIPITATORELECTROSTATIC PRECIPITATOR - It is a device which removes dustIt is a device which removes dustor other finely divided particles from flue gases by charging theor other finely divided particles from flue gases by charging theparticles inductively with an electric field, then attracting them toparticles inductively with an electric field, then attracting them tohighly charged collector plates. Also known as precipitator. The processhighly charged collector plates. Also known as precipitator. The processdepends on two steps. In the first step the suspension passes throughdepends on two steps. In the first step the suspension passes throughan electric discharge (corona discharge) area where ionization of thean electric discharge (corona discharge) area where ionization of thegas occurs. The ions produced collide with the suspended particles andgas occurs. The ions produced collide with the suspended particles and confer on them an electric charge. The charged particles drift towardconfer on them an electric charge. The charged particles drift towardan electrode of opposite sign and are deposited on the electrode wherean electrode of opposite sign and are deposited on the electrode wheretheir electric charge is neutralized. The phenomenon would be moretheir electric charge is neutralized. The phenomenon would be morecorrectly designated as electrodeposition from the gas phase.correctly designated as electrodeposition from the gas phase.

The use of electrostatic precipitators has become common inThe use of electrostatic precipitators has become common innumerous industrial applications. Among the advantages of thenumerous industrial applications. Among the advantages of theelectrostatic precipitator are its ability to handle large volumes of gas,electrostatic precipitator are its ability to handle large volumes of gas,at elevated temperatures if necessary, with a reasonably smallat elevated temperatures if necessary, with a reasonably smallpressure drop, and the removal of particles in the micrometer range.pressure drop, and the removal of particles in the micrometer range. Some of the usual applications are: (1) removal of dirt from flue gasesSome of the usual applications are: (1) removal of dirt from flue gasesin steam plants; (2) cleaning of air to remove fungi and bacteria inin steam plants; (2) cleaning of air to remove fungi and bacteria inestablishments producing antibiotics and other drugs, and in operatingestablishments producing antibiotics and other drugs, and in operatingrooms; (3) cleaning of air in ventilation and air conditioning systems;rooms; (3) cleaning of air in ventilation and air conditioning systems; (4) removal of oil mists in machine shops and acid mists in chemical(4) removal of oil mists in machine shops and acid mists in chemical process plants; (5) cleaning of blast furnace gases; (6) recovery ofprocess plants; (5) cleaning of blast furnace gases; (6) recovery of

valuable materials such as oxides of copper, lead, and tin; and (7)valuable materials such as oxides of copper, lead, and tin; and (7)separation of rutile from zirconium sand.separation of rutile from zirconium sand.

FAN OR DRAUGHT SYSTEMFAN OR DRAUGHT SYSTEM

In a boiler it is essential to supply a controlled amount of air to theIn a boiler it is essential to supply a controlled amount of air to thefurnace for effective combustion of fuel and to evacuate hot gasesfurnace for effective combustion of fuel and to evacuate hot gases


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formed in the furnace through the various heat transfer area of theformed in the furnace through the various heat transfer area of theboiler. This can be done by using a chimney or mechanical device suchboiler. This can be done by using a chimney or mechanical device such as fans which acts as pump.as fans which acts as pump.

i)) Natural draughtNatural draught

When the required flow of air and flue gas through a boiler can beWhen the required flow of air and flue gas through a boiler can be obtained by the stack (chimney) alone, the system is called naturalobtained by the stack (chimney) alone, the system is called naturaldraught. When the gas within the stack is hot, its specific weight willdraught. When the gas within the stack is hot, its specific weight will be less than the cool air outside; therefore the unit pressure at thebe less than the cool air outside; therefore the unit pressure at the base of stack resulting from weight of the column of hot gas within thebase of stack resulting from weight of the column of hot gas within thestack will be less than the column of extreme cool air. The difference instack will be less than the column of extreme cool air. The difference inthe pressure will cause a flow of gas through opening in base of stack.the pressure will cause a flow of gas through opening in base of stack. Also the chimney is form of nozzle, so the pressure at top is very smallAlso the chimney is form of nozzle, so the pressure at top is very smalland gases flow from high pressure to low pressure at the top.and gases flow from high pressure to low pressure at the top.

ii) Mechanized draughtMechanized draught

There are 3 types of mechanized draught systemsThere are 3 types of mechanized draught systems

1. Forced draught systemForced draught system

2. Induced draught systemInduced draught system

3. Balanced draught systemBalanced draught system

Forced draughtForced draught: In this system a fan called Forced draught fan isIn this system a fan called Forced draught fan isinstalled at the inlet of the boiler. This fan forces the atmospheric airinstalled at the inlet of the boiler. This fan forces the atmospheric air through the boiler furnace and pushes out the hot gases from thethrough the boiler furnace and pushes out the hot gases from thefurnace through superheater, reheater, economiser and air heater tofurnace through superheater, reheater, economiser and air heater tostacks.stacks.

Induced draughtInduced draught: Here a fan called ID fan is provided at the outlet: Here a fan called ID fan is provided at the outlet

of boiler, that is, just before the chimney. This fan sucks hot gases fromof boiler, that is, just before the chimney. This fan sucks hot gases fromthe furnace through the superheaters, economiser, reheater andthe furnace through the superheaters, economiser, reheater anddischarges gas into the chimney. This results in the furnace pressuredischarges gas into the chimney. This results in the furnace pressurelower than atmosphere and affects the flow of air from outside to thelower than atmosphere and affects the flow of air from outside to thefurnace.furnace.

Balanced draughtBalanced draught:-In this system both FD fan and ID fan are:-In this system both FD fan and ID fan areprovided. The FD fan is utilized to draw control quantity of air fromprovided. The FD fan is utilized to draw control quantity of air from atmosphere and force the same into furnace. The ID fan sucks theatmosphere and force the same into furnace. The ID fan sucks theproduct of combustion from furnace and discharges into chimney. Theproduct of combustion from furnace and discharges into chimney. Thepoint where draught is zero is called balancing point.point where draught is zero is called balancing point.

SPECIFICATION OF COMPONENTS USED INSPECIFICATION OF COMPONENTS USED INPLANTPLANT


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GENERATOR-GENERATOR-Manufacturer-bhelManufacturer-bhelDivision -haridwarDivision -haridwar

Rpm-300Rpm-300Coolent- water and hydrogenCoolent- water and hydrogen

Hz- 50Hz- 50kW - 210000kW - 210000kVA- 247000kVA- 247000

TURBINE-TURBINE-

Manufacturer- lanin arade metal worksManufacturer- lanin arade metal worksType- impulse+reaction typeType- impulse+reaction type

Pressure at high pressure turbine-135 kg/cmPressure at high pressure turbine-135 kg/cm22

Pressure at intermediate pressure turbine- 75 kg/cmPressure at intermediate pressure turbine- 75 kg/cm22

Pressure at low pressure turbine- 20 kg/cmPressure at low pressure turbine- 20 kg/cm22

CONDENSER-CONDENSER-

Type- surface type condenserType- surface type condenser

Condensation pressure- 10 kg/cmCondensation pressure- 10 kg/cm22

Water cooled from 540 to 55Water cooled from 540 to 55CC

PULVERIZER OR MILLERPULVERIZER OR MILLER

Type- bowl and race type(1 bowl 3 race)Type- bowl and race type(1 bowl 3 race)Bowl operating motor- 320kWBowl operating motor- 320kW

Coal size after crusushing-75mCoal size after crusushing-75mNo. of miller- 6(5 working, 1 standby)No. of miller- 6(5 working, 1 standby)

Name of miller-A(Agra),B(Bombay), C(Calcutta), D(Delhi), E(England),Name of miller-A(Agra),B(Bombay), C(Calcutta), D(Delhi), E(England),F(foreign)F(foreign)

BOILER-BOILER-

Type- tangential fired sub critical water tube boilerType- tangential fired sub critical water tube boiler

Pressure- 130 to 150 kg/cmPressure- 130 to 150 kg/cm22

Temperature- 540Temperature- 540CCboiler drum capacity-3500kiloLitresboiler drum capacity-3500kiloLitres

SUPERHEATER-SUPERHEATER-

Type-convection superheaterType-convection superheaterTemperature rise from 340 to 540Temperature rise from 340 to 540CC

ECONOMISERECONOMISER

Type-convection typeType-convection typeTerperature rise from 240 to 340Terperature rise from 240 to 340CC

FANFAN

Air sucked- 240 tonnes/ hourAir sucked- 240 tonnes/ houra. Induced draught fanInduced draught fan

kW- 1250,rpm- 1483kW- 1250,rpm- 1483b. forced draught fanforced draught fan

kW-1400,rpm-1600kW-1400,rpm-1600

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