operation & maintenance instruction manual

OPERATION & MAINTENANCE

INSTRUCTION MANUAL (HEAT EXCHANGERS)

MANUAL NO: 4-OMD-HET-GEN-05024-S00-R04

2X660MW MAITREE SUPER THERMAL POWER PROJECT

RAMPAL, BANGLADESH.

Bharat Heavy Electricals Limited Ramachandrapuram, Hyderabad.

FIOFOR INFORMATION ONLY

Date: 17-May-2020

*Approval doesn’t absolve the EPCcontractor of it’s responsibility asspecified in the Contract.

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DISCLAIMER

This manual contains information on the operation and maintenance of the BHEL supplied equipment. The copyright in all the documents, drawings etc. in relation to the BHEL supplied equipment vests in and is the property of BHEL. The contents hereof should not be used or shared by the receiver with any third party without express written permission of BHEL. The contents of this manual must be read as a whole before starting operation and maintenance of the supplied equipment. If any of the content(s) of the manual seems unclear or incomplete, please contact BHEL before starting operation and maintenance of the said equipment. It is an essential pre-requisite for the satisfactory operation and maintenance that the operating and maintenance personnel are fully familiar with the design and that the said personnel have received thorough training in operating and maintaining the machine/unit/equipment. It is further essential for safe operation of the machine/unit/equipment that personnel have read, understood and followed the safety instructions contained in the manual. In case of any conflict between terms and conditions of this manual and the contract specifications, drawings, instruction sheets or any other contract related documents, the contract conditions/documents shall prevail. The contract specific conditions/documents shall apply in priority. BHEL offers no warranty, guarantee or representation regarding the completeness of any information contained in this manual or any of the amendments made thereto. BHEL does not extend warranty of any kind, including, without limitation, any warranty of design, merchantability or fitness for a particular purpose. BHEL does not assume responsibility of any errors or omissions in the information or documents which are referenced by or linked to this manual. The entire risk as to the results and performance obtained from using the information is assumed by the user. BHEL in no event shall be liable to the user or any third party for any incidental, consequential, indirect, special, or exemplary damages, including, without limitation, loss of business, loss of profits, business interruption, loss of business information or any pecuniary loss, arising out of, in connection with, or relating to the use of the information contained in or referenced by this manual, even if BHEL has been advised of the possibility of such damages. This manual and the information contained therein may include technical, other inaccuracies or typographical errors. BHEL periodically changes the information herein which will be incorporated into new additions/amendments to the manual. BHEL reserves the right to add, delete, amend or modify the information contained in the manual from time to time in the form of circulars, letters, notes etc. for better operation and safety of the machine/unit/equipment. The said additions or amendments are meant for improvement /better operations of the machine/unit/equipment and such amendments shall not give any right to claim any compensation or damages under any circumstances. BHEL shall in no way be responsible (i) in case the machine/unit/equipment mal-functions due to any non-compliance of the instructions contained in this manual (ii) in case of operation of the machine/unit/equipment beyond the rate limits (iii) in case of operation of the machine and equipment in conditions different from the prescribed conditions of the manual.


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HEAT EXCHANGERS AND FABRICATION ENGINEERING

BHARAT HEAVY ELECTRICALS LIMITED –HYDERABAD

CONTENTS

PROJECT: 2X660MW MAITREE STPP RAMPAL, BANGLADESH.

SALE ORDER: M-PA-1060

SECTION DESCRIPTION PAGE NO.

I

a.

b.

c.

DEAERATOR

DESCRIPTION

DATA SHEET

DRAWING

2

36

47

II

a.

b.

c.

FEED WATER HEATER

DESCRIPTION

DATA SHEET

DRAWING

50

73

104

III

a.

b.

c.

LUBE OIL COOLER

DESCRIPTION

DATA SHEET

DRAWING

122

130

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�

DEAERATOR

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Description, Installation, Maintenance and Operation Instructions

DEAERATOR

Bharat Heavy Electricals Limited 1 Of 35

PREFACE

The principles of dearation of water are outlined in these instructions and the physical equipment which accomplishes this deration are basically described. It is the intent of these instructions to present these principles in broad terms only and to allow this manual to recover any possible variations of equipment or operation conditions.

Dearating heaters are flexible and will meet the guarantees of deaeration and accordance with these instruction provided that operating conditions and load fluctuations are within the design limits and operating personnel understand the principles of deaeration and the equipment.

Any drawings contained within this bulletin are general and for exact details, please refer to the engineering drawings. This applies to both the drawings of BHEL equipment and any auxiliary equipment used in conjunction with the deaerator.

FUNCTION

The function of the deaerating heater is to remove dissolve non-condensable gases and to heat boiler feed water. A deaerating heater consists of a pressure vessel in which water and steam are mixed in a controlled manner. When this occurs, water temperature rises, and all non-condensable dissolved gases are liberated and removed and the effluent water may be

considered corrosion free from an oxygen or carbon dioxide standpoint. Free air or other non-condensable gases should be vented prior permitting the fluid to enter the deaerator.

A deaerating heater is the watch dog of a boiler plant as it protects the feed pumps, piping boilers, and any other piece of equipment that is in the boiler feed and return cycle from the effects of corrective gases, ie., oxygen and carbon dioxide, to a level where they are no longer a corrosion factor.

PRINCIPLES OF DEAERATION

There is physical law which states that the solubility of any gas in a liquid is directly proportional to the partial pressure of the gas above the liquid surface. Another law states, the solubility of a gas in a liquid decreases with an increase in temperature of the liquid. Experience has shown that more rapid and more complete removal of non condensable gases from a liquid is obtained when the liquid is vigorously boiled or scrubbed by condensable or carrier gas bubbles. Therefore essentially the deaerating heater must first heat the feed water to as high temperature as possible i.e., to the temperature corresponding to the steam pressure. It must vigorously boil and scrub the heater water with fresh steam, which can carry to the liquid surface any traces of oxygen and carbon dioxide. The partial pressure of the oxygen and carbon dioxide in the steam atmosphere must be maintained as low as possible, particularly at the point where the deaerated water separates from the

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steam. Non-condensible gases must be continually withdrawn from the heater at the rate at which they are being liberated.

OPERATION

A deaerating heater utilizes steam by spraying the incoming water into an atmosphere of steam in the preheater section (first stage). It then mixes this water with fresh incoming steam in the deaerator section (second stage).

In the first stage the water is heated to within 2 degrees of steam saturation temperature and virtually all of the oxygen and free carbon dioxide are removed. This is accomplished by spraying the water through self-adjusting spray valves which are designed to produce a uniform spray film under all conditions of load and consequently a constant temperature and uniform gas removal is obtained at this point.

From the first stage the preheated water, containing minute traces of dissolved gases, flows into the second stage. This section consists of either a distributor or several assemblies of trays. Here the water is in intimate contact with an excess of fresh gas-free steam. The steam passes into this stage and it is mixed with the preheated water. Deaeration is accomplished at all rates of flow if conditions are maintained in accordance with design criteria. Very little steam is condensed here as the incoming water

has a high temperature caused by the preheating. The steam then rises to the first stage and carries the small traces of residual gases. In the first stage most of the steam is condensed and the remaining gas pass to the vent where the non-condensible gases flow to the atmosphere. A very small amount of steam is also discharged to the atmosphere which assures that the deaerating heater is adequately vented at all times.

The water which leaves the second stage falls to the storage tanks where it is stored for use. At-this time the water is completely deaerted and is seated to the steam saturation temperature corresponding to the pressure within the vessel.

PREPARATION FOR SHIPMENT

Usually all deaerating heaters are shipped with the main shell completely assembled and with all internal parts in position. Normally the only exception to this would be very large tray type heaters for which the trays are sometimes shipped loose. If trays are field installed, attention must be paid to the caution below.

CAUTION : THE DEAERATOR IS SOMETIMES PREPARED FOR SHIPMENT USING AN INERT (OXYGENLESS) GAS. IF YOUR EQUIPMENT HAS BEEN PURCHASED WITH THIS PROTEC-TION, BEFORE ENTRY MAKE SURE THAT PRECAUTIONS CONTAINED IN THE SAFETY SECTION OF THIS

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MANUAL ARE REVIEWED. IF USER USES INERT GAS PROTECTION DURING LAYUP, USER IS RESPONSIBLE FOR PRVIDING APPROPRIATE SAFE WARING.

Accessories and piping are usually shipped separately for ease in heandling and to avoid damage in transit. When accessories and piping are shipped separately, each item is described completely on the job Bill of Material. It is simple matter for the purchaser to identify each piece received by referring to the Bill of Material. Some components may be shipped inside the vessels.

Always check the storage tank and deaerator for any loose pars. When the deaerating heater is extremely large or where clearances will not permitted shipment of a heater and storage tank as one unit, or when the customer specifically requests dissembled units, the main tanks may be shipped in two or more pieces. When required for mating the two vessels, pipe spools with a stock allowance are provided for ease of fit up and assembly. Field joints are always marked and clearly identified on the engineering drawings. Therefore, a deaerating heater can be easily reassembled by the purchaser, as the shell normally are completely assembled and tested before being dismantled and sealed for shipment. Normally, only field piping connection either welded or flanged, between the heater and storage tank, must be made. Large vessels are either skidded or

supported on their own saddles for ease to handling. All nozzles and opening are sealed to avoid entrance of foreign matter. Smaller parts and accessories are normally boxed and tagged. All parts should be checked and if any breakage or shortage occurs, this should be reported immediately to carries representative. If the parts are not to be erected immediately, it is best that the boxes remain closed to avoid there being mislaid or subjected to the elements.

FOUNDATIONS :

Foundations should be level and of adequate strength to support the maximum loads that the deaerating heater can impose upon it. The foundation should be designed to carry the “flood weight” which is the maximum weight of the deaerating heater vessel when completely installed and flooded or hydrostatic test. In addtion to this, there must be an added allowance for piping, platforms stairs and any other attachments on the deaerating heater.

The deaerating heater should be firmly bolted to the support steel or reinforced concrete foundation.

INSTALLATION

CAUTION : SAFETY PRECAUTIONS MUST BE EXERCISED DURING INSTALLATION OF THE DEAERATOR. ALL CHAINS, SLINGS, HOOKS AND LIFTING EQUIPMENT MUST BE CHECKED PRIOR TO USE. REVIEW ALL ENGINEERING

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DRAWINGS TO DETERMINE THE WEIGHT OF PARTS TO BE LIFTED AND MADE CERTAIN THAT LIFTING EQUIPMENT CAN HANDLE THE LOADS SAFELY.

The weight shown on the engineering drawings as “shipping or dry weight”, is the approximate weight of the deaerating vessel as shipped. Rigging facilities must be available to handle this weight both for unloading and raising the unit to its foundation. Qualified riggers should be used to set the deaerating heater upon the foundation. Slings blocks and handling rigging must be carefully laced and care must be exercised to avoid damaging nozzles or internal parts of the heater. Do not depend on lifting lugs, if present, for hosting. VX the vessel is placed upon the foundation, it may be shimmed if necessary.

The installation procedure may include assembly of spray valves and trays. If this assembly is required, it is necessary to check for inert (oxygenless) gas protection. If this protection has been provided, the Safety Section of this manual must be consulted before entry into the vessel.

INSULATION

The deaerating heater, storage tank and all equipment carruying hot water or containing steam should be thoroughly insulated to prevent loss of heat. This includes all external stiffing rings. Sample connections and thermometer walls should not be covered, and provision should be made

to allow for annual inspection through manholes and to inspect control valves, level controllers, etc. without damping the insulation and covering.

The insulation selection, in addition to protecting the vessel and preventing heat loss, must take personnel health and safety into consideration, the outer surface of the insulation and lagging steam must be maintained at a temperature which is safe for personnel working on or near the equipment. Insulation materials must comply with OSHA regulations.

ELEVATION OF DEAERATING HEATER

Any deaerating heater must be elevated above the boiler feed pump to insure sufficient net positive suction at the inlet side of the boiler feed pump. The minimum heat required on the suction of the pump should be carefully checked with the pump manufacturer, emphasizing the fact that the pump is handling water at a temperature corresponding to the saturated temperature of the steam supplied to the deaerating heater. Flashing and consequent “steam blinding” of the pump may occur if the boiler feed pump is operated with a low or negative suction head. The suction head is considered that distance from the low water line in the deaerating heater or bottom of storage tank to the centerline of the feed pump.

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WATER PRESSURE

Sufficient water pressure must be supplied at the inlet of the deaerating heater for all entering water supplied; this pressure must be high enough to overcome any loss of head caused by pipe friction, control valves and spray valves. It must also overcome internal steam pressure. Normally, minimum pressures for condensate not flowing through controllers, etc., must be equal to the steam pressure in the vessel plus approximately 3 psi at the heater connection where spray valves are used and approximately 7.9 psi is required where spray pipes are used.

Inlet control valves have been selected to operate within the range or pressures. If the pressure is too low, sufficient water will not enter the heater. If water pressure is too high, difficulty may be experienced with the control valve. A high pressure drop across control valve could cause valve clatter, “hunting” of the unit, and reduce the efficiency of the plant. In such cases, it is necessary t install a water pressure deducting valve and regulator.

STEAM REQUIREMENTS

Steam is required to heat and deaerate the water in a deaerating heater. The amount of steam required does not depend upon the design of a deaerating heater, by only upon thermodynamic laws to determine accurately the amount of steam required, it is necessary to perform heat balance calculations.

The amount of steam consumed by any deaerating heater is that amoaunt determined by the heat balance required to heat all of the incoming water to the saturated steam temperature within the heater, plus a minute amount that is vented with the gases loss any flashed steam from hot condensate or trap returns. This calculation should be made with the incoming, water at its lowest temperatures. If there is sufficient exhaust or bleed steam, then makeup or auxiliary steam should be supplied at the required pressure.

The following procedure may be used, the first two methods ‘a’ and ‘b’ are approximations, the third ‘c’ is an exact method. A complete heat balance can be made of the entire heat cycle, in accordance with any established procedures.

a) if the operating system pressure is between 1 and 5 psi, and if the maximum inlet water temperature is below 100 EF, the required amount of steam will be one seventh of the outlet flow.

Q (outlet) (1) = Steam Required in 7

lbs/hr

Example : 50,000 lb/hr. outlet capacity entering at 60 EF heater operating at 2 psi.

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60,000 = 8,750 lb/hr. steam 7

required b) If the operating pressure is

between 1 and 5 psi, and if the inlet water temperature is

between 100°F and 150°F, the required amount of steam will be one tenth of the outlet flow.

Q (outlet) (2) = Steam Required in 10

lbs/hr

Example : 60,000 lb/hr. outlet

capacity entering at 140°F heater operating at 2 psi.

60,000 = 6,000 lb/hr. steam 10

required

c) Exact method

Q = Total deaerator outlet capacity (lb/hr)

Qm = Inlet water (under con-sideration) (lb/hr)

P = Steam pressure (psi) T1 = Steam temperature (sta-

urated temp at inlet

pressure) (°F)

T2 = Water tempertarue (°F) h1 and htg

Then sum all of the flows of required steam for inlet water heating,

reduce any steam volume required by deaerating heater for the loads in question.

Good deaerating can only be obtained if a sufficient steam supply is available to maintain a contiguous positive pressure of at least 0.5 psi gauge on the deaerating heater shell, unless there are special provisions for vacuum operation.

The only cause for a deaerator to operate at lower temperature than saturated steam temperature is the lack of steam caused by having too small a steam makeup valve, an insufficient supply of steam or improper venting.

Vibrating and hammering can be caused by too low a steam pressure supply or some blockage within the passages for steam within the deaertaing heater.

ACCESSOREIS

The Accessories include any of the following pressure gauge glasses, water thermometers, steam thermometers, steam pressure gauges, relief valves, piping, etc., BHEL furnishes only that material which has been listed on the engineering Bill of Material. For operating any of the accessories or auxiliary equipment supplied with the heater, refer to separate instructions which follow, and to the instructions for the accessory equipment.

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ACCESS

CAUTION : BEFORE ANY ENTRY OR ACCESS TO THIS VESSEL, REFER TO THE SAFETY SECTION OF THIS MANUAL

Provisions should be made for platforms or ladders so that various valves, controls and instruments are accessible to the operator. Manholes should be accessible for internal inspection of the equipment.

PIPING CONNECTOONS

Prior to connecting the deaerating heater to the piping, the heater and storage tank should be bolted firmly to the foundation and the interior should be inspected to ascertain that all interior parts are in position and working order.

When connecting steam and water lines to the heater, care should be exercised in the piping arrangement. Include expansion joints, if necessary to avoid imposing excessive piping loads upon the shell. Isolating gage valves in these lines are desirable, as they allow for complete isolation for cleaning or repairing, and are bypassed around inlet control valves or steam pressure reducing valves.

Piping should be supported independently to avoid loads from being exerted upon the heater or storage shall or any nozzles.

The pump suction line should be as large as practical and the use or sharp angle bends should be avoided. The line should be as direct to the boiler feed pump suction as possible. Vent piping should be installed with care to avoid any traps or pockets, a vertical line, short as possible, is best. A gate valve should be installed in this line. An alternative to this would be gate valve with a pipe cap mounted above the valve. This pipe cap should be drilled with an orifice that will allow sufficient venting, this method is most feasible for a system that would have a fairly uniform amount of non-considerable gases venting from it. Care must also be taken to avoid closing the gate valve at any time except for maintenance or change of the orifice.

The drain line should be piped to waste and all of the connections made in accordance with the layout drawings using usual piping practice.

Sampling lines should be installed using extreme care to avoid leakage of air into the line for a full description of the installation of sampling lines, refer to section under Oxygen Testing.

Thermometers

Thermometers are supplied only when ordered and then they are usually of the indicating type. They are installed to indicate the temperature within the storage tank. The thermometer wells are usually of the separable socket type with extension neck and with union

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connections. It is possible to remove the thermometer for calibration without reducing the pressure in the deaerating heater. For special installations, indicating remote, or recording instruments can be supplied. Temperatures external to the heater often supply useful information. This would be the temperature of any water steam coming to the heater, temperature of steam to the heater, and the temperature of the water at the boiler feed pump.

PRESSURE GAUGES

Pressure gauges are only supplied when ordered and are usually of the bourden tube type which are used to indicate the steam pressure. A siphon should be installed between the vessel and the gauge to insure accurate reading of the gauge, the gauges usually installed to indicate steam pressure in the shell of the deaerating heater. On special installations or where specially required for remove control, indicating or recording pressure gauges can be supplied. It is often useful to have pressure at sources external to the heater should information ever be required, such as pressure upstream of the inlet control valves, steam header piping and feed pump suction.

ACCESSORY EQUIPMENT

Relief Valves

Relief valves, when furnished, are not designed to prevent excess pressure in the steam line. They are

designed to relieve excess pressure which might occur in the deaerating heater when steam is flashed from high temperature waters returned to the heater in the form of trapped discharges, condensate returns, etc.

Main steam line should be protected external to the deaerating heater to avoid over pressuring from any cause. They must be sized to completely remove any steam formed from pressure reducing stations, or other control devices, which may be installed between the deaerating heater point of supply. They must also be capable of relieving the complete, volume of steam flowing to the deaerating heater.

Normally, the relief valves supplied have a release, and it is recommended that occasionally, this release be manipulated to check free movement and to avoid freezing of the valve seat. This can also be opened when starting the deaerating heater to relieve displaced air when filling the unit.

WARINING : THE DISCHARGE FROM THESE VALVES CAN CAUSE SEVERE INJURY, PERSONNEL PRO- TECTION SHOULD BE INSTALLED BY THE OWNER OR OPERATOR. REFER TO THE SAFETY SECTION OF THIS MANUAL.

Vacuum Breakers

Vacuum breakers are occasionally supplied to protect shell

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from external pressure where the vessel has not been designed to withstand this force. When a vacuum breaker opens, there is a definite malfunctin within the deaerating heater, as normally this vacuum breaker should never open. It will only open when there is an insufficient supply of steam. Water going to service during these times should conceivably contain dissolved oxygen.

Vacuum breakers which are supplied are steam tight, suitable for the design pressure of the vessel, and are set to open at the slightest vacuum. These should be checked periodically to insure that the seats have not frozen or allowed to become excessively dirty.

Other equipment

For a description of the other equipment sometimes furnished in deaerating heaters, such as inlet valves and controllers, overflow valves and controllers, tray banks, spray valves, etc., refer to the appropriate sections of this manual which outline installation and operating procedures to be used.

MAINTENANCE AND INSPECTION

Normally, deaerating equipment requires relatively minimal maintenance. The operation should be completely automatic. For normal operation, little or no maintenances required, except for the usual attention required for instrumentation and controls.

Complete annual inspection should be made of this equipment. In

plants where duty is unusually severe, or abnormal water supplies are used; inspection should be required semi-annually, or more frequently.

CAUTION : BEFORE ANY ENTRY FOR ACCESS TO THIS VESSEL FOR INSPECTION PURPOSES, REFER TO THE SAFETY SECTION OF THIS MANUAL

These inspections should include the following :

1. Internal inspection for evidence of corrosion, sealing, cracking or broken or worn parts.

2. Spray Valve: Valve must sear firmly. Check under plug for debris. Valve nuts should be tight with no evidence or leakage under gasket. If a disc appears to hand down, the spray valve can easily be adjusted by removing it from the tank, loosening the top lock nut and hand tighten the spring retainer until the valve disc just seats. Then turn one-quarter turn more. Tighten lock nut firmly and reinstall.

3. Spray Nozzle : Should likewise be checked for foreign matter and see that all holes are clean and clear.

4. Check packing of controls are valves, replace if necessary.

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5. Check manhole gasket, replace if there is evidence of leaks or deterioration of the gasket.

6. Check operation of all controllers they should move freely and not have excessive lay. Make any necessary adjustments, paying particular attention to the overflow valve and controller as this is not used frequently and may have a tendency to corrode and freeze into position.

7. open and close all gate valves that have not been used since last inspection. Lubricate when necessary.

8. Recalibrate thermometers, pre-ssure gauges and any other instruments.

9. Inspect all piping connections for evidence of corrosion.

10. Inspect insulation.

11. After unit is returned to service, oxygen testing should be performed with more frequency to ascertain that the vent setting is correct.

OPERATION OF EQUIPMENT

The following procedures should be followed when commencing operation of a deaerating heater, after the unit has been completely installed,

and all equipment has been tested and checked.

CAUTION : BEFORE OPERATION OF THIS EUQIPMENT THE USER MUST READ THIS MANUAL, ESPECIALLY THE SECTION CONCERNING SAFETY

1. The startup period should be carefully planned so that wastage of water and steam to the drain do not unduly overload existing facilities such as pumps, heaters, etc.

2. Flush out all lines and tanks with water until there is no apparent indication of foreign matter or rust. Spray valves and nozzles should be free of all foreign material.

3. Manually check all controls to see that each is working freely and that all shipping stops are removed. Refer to the descriptive literature and operating instructions for proper operation and adjustment of controls, instruments and special equipment.

4. Check to see that all instruments are operating and indicating correctly.

5. Open all vent valves or open orifice bypasses to atmosphere. If orifice plates are not by passed,

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remove the orifice plates to allow free venting to atmosphere.

6. Close the outlet valve from the heater to the feed pump.

7. Start the flow of inlet water and slowly increase to 15% to 30% of the design inlet flow rate.

Important Note : Large industrial and central station deaerators and most scrubber type deaerators which operate 50 PSIG to 150 PSIG frequently have a design temperature rise (inlet water temperature to outlet water temperature) of up to

150°F. Starting up with cold water at high inlet water rates can require steam flows exceeding design limits. This can cause violent pressure fluctuations and possible damage to the internal. The following formula shows the relationship to consider:

Design water rate x design temp. rise x steam spec vol @ design

Startup water rate x start up temp. rise x steam spec vol @ design

8. After making certain that adequate steam pressure is available, open steam valve slowly admitting steam into the deaerator. Expect some reumbling with a cold vessel. Check deaerator pressure gauge and be certain to maintain a positive pressure on the vessel. A

proper start-up is not possible with inadequate steam pressure.

9. Caution: Do not fill the deaerator with steam and then start the water. This will create noise and vibration which can damage the internals of the deaerators. Deaerators not designed for full vacuum can be partially collapsed. Caution is urged even if a vacuum relief valve is installed.

A similar condition can occur where the deaerator sits at idle for a time with steam pressure on the vessel but no water entering a condensate inlet. Since the spray valves are not water tight, the water box will drain and then fill with steam. Where this situation is likely to occur provisions for flushing the steam from the condensate line and water box with water from the deaerator storage tank or other source (at saturation tempera-ture) prior to condensate return must be provided. If hot water is not available the unit must be shut down and started as in steps 5,6 and 7 etc. above.

10. As water moves up to and reaches the operating level, check the operation of the limit switches and inlet controller. Manually continue water flow and check high level over flow controls.

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11. When a strong flow of steam issues from the vents, start throttling back on the vent valves and check storage tank temperatures. The gauge should

red 2° F to 3°F below saturation temperature at the existing pressure.

12. Open steam valve full open so that steam pressure control is operating.

13. Throttle back vent valves to operating positions, Install orifice plates if removed. Final vent valve position or orifice plate sizing must be determined in conjunction with oxygen tests during unit operation.

14. Deaerator is now ready for operation. Open outlet to feed pumps.

RECOMMENDED GOOD PRACTICE FOR TEMPERATURE CHANGES

A deaerator is a direct contact heat exchanger. This type of equipment can be exposed to severe thermal and pressure excursion which can cause damage to the vessel due to stress corrosion, corrosion fatigue and similar phenomena. Cyclic operation is major contributor to the damage. These practices apply to cyclic and non cyclic equipment.

To assure life the guidelines below should be followed.

1. Changing cold or hot water admission to the water box must be accomplished in a controlled manner. The control must assure that rate of temperature change of the metal in the shell or the

water box does not exceed 40°F per hour with instantaneous

changes not greater than 50°F per minute for a total excursion of

150°F.

2. Pressure changes in the heater must be gradual. Pressure changes are accompanied by changes in temperature. The change is temperature should not exceed the limitations above.

3. Cold start up can severely stress a deaerator. It is not unusually to have startup steam with

temperatures of 500 °F and higher. To avoid severe thermal shock it is recommended that cold start ups be preceded by a warmup period. The warm-up consists of slowly admitting startup steam with the vents open and no flow in to the water box. The steam flow should be regulated to permit the steel

shells to heat at a rate of 50°F

per minute up to above 200°F. Water in the storage tank should also be heated to the same value. Note that the heating of the storage tank and its water will be much slower than the heater portion of the deaerator.

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When the entire vessel and its contents are heted the steam supply should be shut off and any remaining steam vapour should be vented. Then proceed with the normal startup.

4. Accelerted cooling is often desirable for repair or maintenance. However, accele-rated cooling using cold water can cause thermal shock and equipment damage Accelerated cooling can be accomplished using a cooling fluid which is

100°F to 150°F lower than the metal temperature until the metal

has cooled to about 250°F. The rate of change of metal

temperature should stay in the

100°F/hr range. Once the metal

is at or below 250°F, cooling

water of 60°F to 70°F may be used.

HYDROSTATIC TESTING

Hydrostatic test pressure may create stresses higher than the equipment design stress. This is not harmful unless hydrostatic tests are performed using very cold water.

In general, the hydrostatic tests should be done using the guidelines of the ASME code, section VIII, division I, paragraph UG-99.

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SPRAY TRAY TYPE DEAERATING HEATER

NOTICE

REFER TO THE SAFETY SECTION OF THIS MANUAL BEFORE OPERATING THE EUQIPMENT

DESCRIPTION

Each Spray Tray type deaerating heater has been specifically tailored to fit the power plant cycle and operating conditions of the individual plant in which it is to be installed. This assures the most efficient use of steam and pressure and energy level in the feed water cycle and the lowest operating cost.

SHELL

The shell structure is fabricated steel. The design pressure is shown on the job bill of material or, if an ASME Code vessel has been ordered, the pressure stamp on the vessel.

SHAPE

In general, the deaerating heater will be of the following shapes:

1. Fully vertical deaerator with a self-contained storage tank.

2. A vertical deaerating heater mounted on ahorizontal storage tank either directly welded (tank car) or connected by nozzles and structural attachments (double shell).

3. A horizontal deaerating heater mounted on a horizontal storage tank.

OPERATION

Regardless of the arrangement of the shell, whether the deaerator and storage tank are jointed together in a common tank or separated in different tank, the operation is identical. Basically, the first stage spray section sprays the water through spray valves which discharge the water in thin films or sheet into the steam which fill the first stage compartment. In this steam space, the

water is heated in within 2-4° of the steam temperature, and virtually all of the dissolved oxygen and free CO2 are removed. The self adjusting, non-clogging spray valves after designed to produce uniform spray action under all conditions of load. Consequently, a constant temperature and uniform gas removal is obtained at this point. The spray valves are arranged so that the preheated water is sprayed downwardly, and does not strike the bottom surface or the sides of the preheated chamber until most of the gases have been removed. Water saturated with oxygen and other non-condensible gases at normal atmospheric temperature will have more than 95% of these gases removed in the first stage preheater.

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The water, containing traces of non-condensible gas then enters the tray section where it is intimately mixed with a large excess of steam. The fresh gas-free steam passes into the second stage rising through a tray stack. Within the second stage section, very little steam is condensed because of the high temperature of the preheated water. Therefore, most of the steam remains in the vapor to carry the small traces of residual dissolved gasses through to the first stage steam space where the steam is condensed in reheating the water. The residual steam then passes to the vent condenser where it is condensed and the non-condensible gases pass to the atmosphere. The water passes counter current to the steam through stainless steel tray assemblies. These assemblies are grouped to form a tray stack, the degree of deaeration is determined by the number of water reversals or changes in direction that occur in passing through the stack. Each reversal exposes another surface of the water to the up-flowing steam. This contact physically loosen the dissolved gas molecules and separates them from solution. The rising steam sweeps the gas into the upper section where it is eliminated. The scrubbing action of the steam assures final deaeration as guaranteed. The second stage of every heater is tailor made for the particular operating conditions prevailing at the point, and the deaerator has been designed for these specific conditions.

INSTALLATION

Inspection should occur before startup. Every deaerating heater has been designed to meet specific operating conditions. Fabricating and inspection procedures are the best know. The material selected for each of the components has been proved over many years of service to be the best for the service within economic considerations. However, before the unit is installed and operated it is strongly suggested that the deaerating heater be rechecked to insure that no damage has occurred to the heater since its inspection.

The spray valves should be checked to insure that they are installed correctly. That is, with the spring on the water side of the water chamber, special silver plated, stainless steel elastic stop nuts are used to fasten the valve to the vessel. These nuts will not loosen under any load. The nuts should be tight and the gasket should be firmly seated. Inspection should be firmly seated. Inspection should be made to make sure that all internal inspection plates are in place, tightly bolted, and that all debris has been removed from the tank. This is especially true after all piping connections are made and the unit is flushed out. It is especially true after all piping connections are made and the unit is flushed out. It is recommended that the water side of the water box be checked if the pipe lines have been hydraulically flushed, as often debris will wash in and will lodge in this compartment and eventually work through the deaerating heater to the boiler feed pump. Baffles should be inspected to insure that no damage

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occurred during shipping or installation, such as cracks of welds or other points that could be subject to damage.

Trays are shipped either separately boxed or are sometimes installed within the heater; refr to your job bill of material under “tray assembly” to determine how these are shipped. If shipped within the heater, inspection should be made to ascertain that no damage accrued during shipping or rigging. The trays should be level and nested together with no gaps or spaces between.

To inspect or install trays, it is necessary to open the access door and the inner tray door or holding braces. The trays should be installed as indicated on the internal assembly drawing. Some trays have serrated edges; install these with the edges (saw teeth) pointing down. For trays with channel shaped sections, install with the channel flanges pointing up.

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INTERNAL VENT CONDENSER (SPRAY VALVE)

THERORY OF OPERATION

Efficient removal of the non-condensable gases from the deaerating heater requires that the vent valve be opened sufficiently to allow complete discharge of the gases passed to the vent condenser outlet pipe. The maximum concentration of the non-condensable gases such as oxygen, carbon dioxide passing out the vent depends on the degree of condensation produced by the steam and gas mixture passing through and around the spray created by the special spray valve. The optimum condition is when the unit is venting all non-condensable gases with the minimum steam loss. This point can only be found through trial and error.

A vent condenser is not function-ing properly when there is entrainment of water in the plume discharging to the atmosphere or where a steam plume cannot be observed, or the plume appears to be puffing. These malfunctions can be caused by any of a number of reasons such as insufficient vent opening, erratic spray valve action or incorrect vent piping.

Installation

All the spray valves should be checked to ascertain if they are tightly bolted in place. Silver plated stainless steel “elastic stop” nuts are normally used one ach stud for fastening purposes. A Teflon gasket is located

between the valve and water box. Spray valves should not require field adjustment as they are pre-set in the factory for zero spring compression. That is, the plugs should just set in the seats with no looseness or apparent spring force, the disc should move freely. The gasket should be firmly seated.

The area immediately above the spray valve should be inspected after all piping is in place. It may be necessary to remove one valve, or cover plate or inspection hole to check for pipe scale, pieces of welding rod, rocks, bottles, or other foreign matter that may have washed in through the piping during the plant or the installation of the water piping which could possible lodge in the spray valve and cause difficulty with the operation of the unit.

VENT PIPING

The vent piping should be install with no sharp vent bends or traps that could obstruct the flow of gases. The ideal vent pipe rises vertically from the heater to the valve located above the junction of the vessel in a short length or pipe above the valve. This is normally satisfactory where a slight amount of steam vapor can be tolerated in the area of the deaerating heater. Where this is not possible, and it becomes necessary to pipe the vent line to the outside atmosphere,, precautions must be taken to avoid consistently long lines with a

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great number of turns. Horizontal runs should be avoided wherever possible trapped pockets in pipe lines must be eliminated if the heater is to operate successfully the vent plume should be visible to the operator to enable him to periodically check the plume, therefore avoid piping the vent to stacks, risers, or other closed systems unless provision is made to allow for this periodic inspection.

VENTING

The vent valve should not be operated in a closed position. Normally the valve should be open one or more turns to allow for complete removal of the gases. To determine the correct amount of opening required, the vent valve should be opened approximately one or two turns and the effect on the operating temperature noted. If no appreciable effect on the temperature is noted after a period of one hour, oxygen tests should then be made to determine the effectiveness of venting; satisfactory reduction of oxygen is obtained when tested by a recognized sampling and testing procedure. The vent seating of the valve can be further decreased by tightening the vent valve. Normally, the plume of steam would indicate sufficient venting if it appears firm and rises approximately 18 inches to three feet above the termination of the pipe. If after reducing the vent valve openings, a drop in operating temperature is observed or a difference between outlet temperature of the water in comparison with the saturated temperature of the steam as shown in a thermodynamic table the indication is that venting is not

adequate and the vent valve or orifice must be opened further.

ORIFICE TYPE VENT

Where loads are very small or where uniform operation (flow rates and pressures) can be expected for long periods of time a fixed orifice may be employed. This would usually consist of a drilled pipe cap, mounted above the vent valve. The vent valve should always be full open, and precautions noted above should be observed, the optimum size of the hole in the orifice cap can best be found by drilling a small hole (1/8” to ¼”) and checking the dissolved oxygen in the effluent, also observe the water temperature to see that it is at saturation temperature of the steam within the heater. If the oxygen reading is high or the temperature is low increase the hole size in the orifice and recheck. Repeat until oxygen is below the guaranteed level and the temperature rises to steam saturation temperature.

SPRAY VALVE

BHEL Spray Valve is the culmi-nation of many years of research and operating experience that recognized the vital role of the “stage one” component in deaerator performance. It is valve that does its job over a wide range of punishing conditions.

There are two basic problems encounted in the spray stage of deaerator operation. The first derives from entrapment of scale or foreign

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objects in spray valves utilizing stem guides. This condition leads to jamming of the valve plug in a fixed position or to distortion of the spray pattern. Even without foreign matter interference, the normal lateral movement of the valve stem against the stem guides can cause rapid wear and breakage.

The second problem occurs when low flow rates, start-ups or sudden flow changes are imposed upon spray valves or other devices of fixed orifice design. This results in a collapse of the spray pattern into solid streams with poor surface exposure, sluggish heat transfer and poor utilization of stream in the vent condensing chamber. It also shortens the exposure the during which pure steam is stripping non-condensables from the water droplets in the tray stack or scrubber.

BHEL Spray Valve eliminates both of these problems. The valve plug stem are held in an adjustable, spring loaded retainer ring by a ½ inch ESNA stainless steel, silver-plated locknut such that the stem is never in contact with the valve body there are no stem guides to scale or clog. The plug is parabolic in shape (elevation) and rests against a spherical seat. During operation the smoothly rounded valve plug remains centered in the valve throat, much the same as a ballon supported by an air jet and the incoming water flows uniformly into the formation of its hollow cone spray pattern.

Variations in flow rates are accommodated by utilising a variable orifice opening which varies in direct

proportion to fluctuations in inlet water flow. This results in athin-walled, hollow cone spray pattern at different flow rates, and the intimate steam-water contact the prevails during this film phase allows for extremely rapid latent heat transfer. Thus the angle and shape of the spray pattern persists despite sudden changes in flow rates such that first stage heating and deaeration are assured.

Spray Valve is so ruggedly con-structed as to withstand the severest of deaerator opening conditions. The body is a type 316 stainless steel investment casting of 3/16” minimum thickness the valve plug and stem are combined in a one piece casting that eliminates the need to bolt these two pieces together. Each valve is securely installed with two ½ inch ESNA stainless steel locknuts that the silver-plated to prevent galling. Gaskets are 100% DuPont Teflon. The pressure drop across a Spray Valve operating at nomal design flow rte is 2.0 pounds per square inch.

The severe operating conditions, erosive impingement, and occasional upsets to which deaerator trays are subjected have been the criteria for the design, material selection and hold –down system for the Heater tray stack, now proven in more than 2500 installations.

Careful inspection and evaluation of any proposed tray design are strongly suggested. The tray stack is an area of the deaerator in which rugged construction and material durability are mandatory, not only because of this

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important performance role served by each tray, but also because transient periods and upset conditions can be very punishing to the entire tray system.

Each tray assembly consist of eight trays arranged in two staggered tiers of four each, and rigidly fastened between two headers with stainless steel rivets, the trays are formed into channels of 16 gauge, type 304 stainless steel.

The assemblies are nested vertically to form tray modules, which sit side by-side to comprise the tray stack. Very important to note is that the tray channel “troughs” are installed facing upward. There are several operating advantages in this arrangement.

First, the water-filled tray channels provide BHEL’s exclusive water cushion effect and absorbs the erosive action of the falling water. Second, the staggered tray channels

create a series of flow reversals and vigorous scrubbing action as the water cascades down ward in the counter-current of steam, Uniquely, the droplets leaving the bottom of the tray stack are being ‘striped’ by the steam in its purest state. Third, the detention time afforded by the tray channel troughs is exceedingly important during wide swings in load and steam volume, because it allows for the necessary steam-water contact time to assure final deaeration.

Finally, it is suggested that the tray assembly be viewed from beneath so as to gain a perspective of the strength and relatively low pressure drop that would be presented by the tray stack to an upset condition. The smooth side of the tray channel faces down such that minimum flow resistance and maximum strength are there to absorb pressure differentials.

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After studying various conside-rations and applying logical engineering procedures, we designed by BHEL tray assembly. The complete assembly was subjected to a series of test to determine the loading capabilities for both steam and water during various states of flow.

The criteria for the tests were based on the fact that the tray stack operates as a packed tower with counter-flow conditions, water falling, steam rising. Normally, most steam is considered in the spray section, therefore, 100% of the stem is considered to completely pass through the tray stack, the water rate would be considered to be both the incoming condensate (and makeup) plus 100% of the condensed steam.

The volume of steam flowing through a stack (at any given load) would be a function of the heat balance for the incoming water and the operating steam pressure within the unit. The require volume of heating steam rising

the stack will cause a pressure drop proportional to its total specific volume. Variable for various rates of flow are, therefore, the incoming water temperature, the operating steam pressure, and the steam pressure drop across the tray stack.

Flashing high pressure extraction stage heart drains are introduced below the trays; when this liquid flashes, all nom-condensable gases are liberated, thus only the flashed steam (later condensed) need be calculated as flowing over the tray stack. The liquid will drop directly into the storage tank. This steam will mix with extraction or makeup steam and flow together upward through the stack helping to drive the gases to the preheating section. Here all steam will be condensed and the resulting condensate will flow down over the trays. Thus, when designing and calculating tray loading, all flashing liquid introduced below the stack may be eliminated form the stack capacity loading.

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RECOMMENDED PROCEDURE FOR STORAGE OR PRESSURE VESSELS

1.0 INTERNAL MAINTENANCE

1.1 Vapour Absorpiton : All openings are to be sealed and taped and a vapor absorbing chemical installed in the shell. Activated alumina or equivalent in quantities of 3 pounds for every 100 cubic foot of vessel.

A rust inhibiting chemical such as Steam washable paint may be used in lieu of or in conjunction with the vapor absorbing chemicals. Application by spray or brush is recommended. Steam washable paint is water soluble and usually removed during the initial flush out. This method is suited for storage periods of six to twelve months depending upon the environment. Longer periods would require that the vapor absorbing chemical or Steam washable paint be replaced.

1.2 Nitrogen Blanketing : No internal preparation of the vessel shell is required, this method required that all openings are tightly sealed, gasketed, and/or

welded shut. Dry nitrogen (or other inert gas) is used to purge the vessel unit the dewpoint is below the expected at the site. Then the vessel is pressurized to 3 to 5 psi and all air vented.

Vessels may be stored in any environment for indefinite periods, but a daily checking of the pressure must be made and the nitrogen cylinders replaced as required.

EXTERNAL PREPARATION.

2.1 In selecting the type of external preparation, consideration must be given to the environmental conditions and maintenance provisions available. Exposure environments arranged in order to increasing severity are as flows:

1. Dry interior climate or arid regions.

2. Rural or light industrial areas.

3. Frequently set climates.

4. Continuously wet climates.

5. Corrosive areas.

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2.2 Paint systems for condition #1 usually consist of a single coat or red oxide primer.

For the remaining conditions, paint systems would normally consists of one or two coats of rusting inhibiting primer and one or two finish cots depending on the severity of the conditions before selecting painting systems and materials for conditions three through five, consideration must be given to the specific climate condition at the storage site.

2.3 Where day-night temperature

changes exceed 30°F, special attention should be given to the preparation of the metal surface and selection of the primer paint.

Under these conditions the metal surfaces should be blast cleaned to remove at mill scale which might otherwise flake off due to expansion and contracting of the vessel.

The type of primer and finish system selected should be compatible with the particular expansion characteristics of the vessel and the final operating temperature.

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Suggested paint systems are as follows:

PAINT SYSTEM

PRIMER COAT FINISH COAT

EXPLOSURE FIRST COAT SECOND COAT FIRST COAT SECOND COAT

1 Red Oxide Primer

Not Required Not Required Not Required

2 Red Oxide Primer

Not Required Not Required Not Required

3 Red Oxide Primer

Red Oxide Primer High Build Polyamide

Note Required

4 Inorganic Zinc Inorganic Zinc High Build

Polyamide Epoxy

Note Required

5 Inorganic Zinc Inorganic Zinc High Build

Polyamide Epoxy

High Build Polyamide Epoxy

3.0 MAINTENANCE REUQIRE-MENTS :

3.1 Short-term storage (upto 12 months) :

The absorption material should be removed after 3 months or replaced as required. Remove satura-ted and replace with dry absorbent from upopened sealed container. The exterior portions of the shell are to be visually inspected periodically.

3.2 Long-term storage (ove 12 months) :

The first gas cylinders and vessel must be checked weekly for any loss of pressure and replaced as required.

The exterior portions of the shell are to be visually inspected periodically and the finish repaired as required using the finish paint specified.

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4.0 SUGGESTED PRIME AND FINISH COATS :

4.1 Prime coat

Red Oxide Primer Red Oxide Primer Inorganic Zinc

4.2 Finish Coat

Polyamide Epoxy

4.3 Surface Preparation:

Application and dry film thickness are to be in accordance with the manufactures recommen-dations for the paint selected

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ALL SAFETY BEGINS AND ENDS WITH A PRUDENT, RESPONSIBLE PERSON WHOSE WELFARE IS THE PRIMARY CONCERN. THERE IS NO GREATER

SAFETY PRACTICE THAN THE CARE AND COMMON SENSE EXERCISED BY YOU

BOILER PLANT SYSTEM

The deaerator is only part of a large boiler/feed water system. Persons who come in contact with the system must known all safety rules of the deaerator and connecting and related equipment, the owner must provide the overall system or Power Plant Safety Procedures.

DEAERATOR

Following are potential dangers associated with a deaerator, DO NOT attempt to disassemble, repair, perform maintenance or otherwise work on a deaerator until all the potential dangers have been considered and their respective safety precautions followed.

HIGH PRESSURE

The deaerator lis pressurized during operation and the pressure may remain high after the equipment is shutoff. Removal of man ways covers, inspection ports or any bolted connections while pressure exists in the vessel can cause the covers, etc., to break loose or discharge hot, high pressure fluids which could cause injury. Therefore, disassembly or work on the deaerator should not begin until the following precautions have been taken:

1. isolate the vessel from the boiler system to insure that there ca be

no operation, residual or otherwise, of the deaerator Plant System Safety procedures must be consulted to insure proper isolation.

2. Check to see that pressure gauges are properly functioning and that the pressure indicators show zero pressure.

3. Carefully open vent valves provided on vessel. Open valves very slowly. Listen for hissing sounds and observe any escaping steam or fluids. If hissing or escaping fluids are present, do not continue to open until all sound or fluid discharge stops.

HIGH TEMPERATURE

The deaerator operates at high temperature that could cause severe burns. When the vessel is shut off it can take hours or days to cool to safe temperatures. Any temperature in excess

of 100°F could also indicate the pressure of internal pressure. Therefore, disassembly or contact with metal parts should not begin until the following precautions have been taken:

1. Isolate the vessel from the boiler system to insure that there can be no operation, residual or other wise, of the deaerator. Plant System Safety procedures must

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be consulted to insure proper isolation.

2. Check thermometers or other temperature indicators for proper functioning and assure that

temperature is less than 100° F.

3. Use a temperature sensor or comparable devise to determine whether the deaerator has sufficiently cooled.

INTERNAL DANGER

Extreme caution should be exercised before entering the deaerator. First, deaerators may, contain oxygen less gases (e.g., nitrogen) that can cause severe illness or death in inhaled. Deaerators are frequently shipped with nitrogen. Many owners and users of deaerators also pressurize the deaerators with nitrogen during short or longterm inactivity. Nitrogen is colorless and odorless and cannot be easily detected. Because of the absence of oxygen in gases such as nitrogen, inhalation of sufficient amounts can cause severe illness or death. Therefore, do not enter the deaerator until the precaustions listed below have been taken.

Second, the inside of the deaerator may be very light and confining. It may also could cause injury. Any person entering a deaerator should be knowledgeable of the proposed Occupational Safety and Health Act requirements on confined space entry and should follow the precautions listed below.

The following general precautions must be taken before entering the deaerator :

1. Isolate the vessel from the boiler system to insure that their can be no operation, residual or otherwise, of the deaerator. Plant System Safety procedures must be consulted to insure proper isolation.

2. The work crew should consist of two or more people at all times.

3. Determine that the deaerator contains sufficient oxygen and does not contain any other dangerous gas.

4. Open all vents, manway, or access openings to permit al oxygen less gas to escape and properly ventilate the deaerator. It may be necessary to utilize exhaust fans, ventilators and blowers to speed the ventilation process. Maintain adequate circulation of oxygen throughout work on the deaerator.

5. Provide adequate scaffolding, platforms or ladders.

6. Provide adequate lighting.

7. Understanding the construction of the equipment all relevant safety requirements.

8. Use appropriate safety equipment including, but not limited to, hard hats, safety glasses or goggles,

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gloves and heavy duty work clothing.

GENERAL MAINTENANCE

The maintenance section of this manual and the instructions in the Accessory section provide normal maintenance procedures for the deaerator. Additionally, the following maintenance inspections should be performed to assure continued safe operation.

1. Inspect for cracks, breakage of internal parts and internal erosion or corrosion in or near welds or pressure parts (e.g., shells and heads).

2. Inspect pumps for loose bolts or coupling parts. If the pumps are disassembled, examine all bearings, shafts, impellers and seals for wear and damage.

3. Safety and relief valves should be activated periodically to assure proper performance. These valves should also be inspected to assure that no external devices such as “gags” or extraneous parts can impede proper operation.

4. Make certain that all safety tags are replaced when maintenance and inspections are complete.

ACCESSORY EQUIPMENT

Safety Valves, Relief Valves and Other Blow-off Type Equipment

All deaerators are protected against damge by one or more safety devices. These devices are designed to discharge in the event that some operating conditions causes the deaerator to exceed the standard operating level. This equipment partially relieves the pressure in the vessel and prevents damage.

The discharge from the equipment is extremely hot and can cause severe injury. Therefore, the following safety precautions should be observed in order to prevent personal injury.

1. If customer is installing these devices, locate them in areas where personnel cannot come in close contact during operation.

2. Each device should have a suitable exhaust duct, pipe or deflector to insure the discharge cannot cause personal injury.

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PRECAUTIONS TO BE TAKEN BEFORE PUTTING AND OPERATION

Starting, operating and shutting down of the equipment requires specific instructions, with emphasis on load limitations, as well as the order of start-up and shutdown. The plant operating instructions, general arrangement drawings, specification sheets, and name plates are to be reviewed prior to operating these equipments.

The following are precautions that should be reviewed when operating these equipments.

Start-up

The equipment operation should not be undertaken if any of the protective devices are known to be faulty.

The heat exchangers are not to be operated at fluid temperatures higher than those shown on the specification sheet. They must not be subjected to abrupt temperature fluctuations, Hot fluid must not be introduced rapidly when the heat exchanger is cold, nor cold fluid when the heat exchanger is hot.

Check the tightness of all permanent plugs and covers prior to pressuring/ charring the equipment. The steam lines must be free form all condensate to prevent damage to the internals by slug flow.

PRECAUTION TO BE TAKEN DURING OPERATION

While enough care has been taken in the design, material selection & manufac-turing of the equipment accordingly sufficient margins have been provided, it is but very important to have a close look at the following while operating the equipment so as to get the most out of them.

OPERATING PARAMETERS

All heat exchangers are to be operated within the design/operating parameters. The fluid flow pressures & temperatures can be ascertained from the equipment data sheets and the actual flow parameters are to be regularly compared with the design values. Any significant variation in the flow parameters need to be immediately looked into and suitable corrective action should be taken.

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CHECKLIST BEFORE STARTUP

1. Check whether all the associated works are completed.

2. Check whether all the trays are in place.

3. Check whether the orifices are in position.

4. Check and float the safety valve.

5. Check whether all the instruments are calibrated and mounted.

6. Check whether all the connections to the deaerator are properly made.

7. Check whether leakages if any are arrested.

DO’S AND DON’TS

a) Do’s :

1. Ensure that the feed water supply precedes the steam supply at the time of starting.

2. Ensure whether the temperature and pressure are maintained at the rated values. If not mani-pulated the steam inlet valve to achieve the same.

3. Monitor the level of condensate in the feed in the feed storage tank.

4. Check oxygen content at outlet periodically.

5. Ensure that non-condensables are being continuously vented to atmosphere.

6. Ensure that the operation of deaerator is free from water hammer. This can be avoided by opening and closing the valves gradually.

7. Ensure that there is a continuous flow of feed water from the feed storage tank after the levels have stabilised.

8. Monitor all the supervisory and measuring instruments.

9. Ensure that the supply of steam to the deaerator is stopped before that of water at the time of stopping in the deaerator.

10. Float the deaerator to the auxiliary steam source when the unit trips.

b) Don’ts

1. Do not add excessive condensate or reduce steam flow in the initial stages which will lower the pressure in the pressure in the deaerator.

2. Do not allow the levels in the feed storage tank to fluctuate widely from the normal.

3. Donot allow the pressure to drop raidly.

4. Do not operate deaerator from unit control board when automatic controls are not in order.

5. Do not admit steam into the deaerator till the required temperature (by initial heating) is achieved in the feed storage tank.

6. Do not admit feed water into the deaertor till the initial heating is over.

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TROUBLE SHOORING 1. High oxygen content to outlet:

The most commonly encounted problem during operation of a deaerator are : 1. High oxygen content at outlet

2. Flooding of vents.

3. Water Hammer and

4. Fluctuations in level and pressure.

The performance of deaerator is greatly affected when the parameters are not adhered to. This results in the high oxygen content at the deaerator outlet. Given below are some of the reasons and actions to be taken in overcome these problems.

Reasons Actions

a. Condensate inlet temperature low Check condensate inlet temperature

b. Condensate inlet quantity high Check condensate inlet quantity.

c. Steam inlet quantity low Check the functioning of inlet steam valve.

d. Dislocating or being or damage of trays.

Rectify the trays during shutdown.

2. Flooding of vents :

Under this condition water appears at the vents on the header. Causes for occurrence of this phenomenon are listed below.

Reasons Action

a) Deaerator overloaded Check and control the condensate inlet temp.

3. Water Hammer :

Abrupt closing or opening of valves give rise to water hammer. The valves should be closed or opened gradually

4. Fluctuations in level and pressure :

Reasons Action

a) Faulty operation of level controls Study the level control system and take suitable action

b) Irregular flow of condensate Study and tune the control system

c) Abnormal load fluctuations Study and tune the control system

d) Level gauges and pressure gauges not reading properly

Check and rectify.

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CHECK LIST DUIRNG SHUTDOWN

1. During prolonged shutdown check whether the steam and water are drained completely and the equipment is kept dry.

Dos and Don’ts during shut down:

a) Do’s

1. Check whether the trays inside the header are choked.

2. Check whether the vent orifices are choked.

3. Check whether the holes in initial heating pipe are choked.

4. Check and tighten “U” clamps of heating steam line inside storage tank.

5. Check packings of valves and replace them if necessary.

6. Check the manhold gasket and replace it if necessary.

7. Check operation of all controllers. They should move freely and not have excessive play.

8. Check & tighten the spray valve fixing nuts and bolts.

b) Don’ts:

1. Do not force open any compo-nents when the deaerator is taken up for maintenance and repair.

MAINTENANCE PROCEDURE

1. LIST OF TOOLS & SPARES

1. Spanners and wrenches of size M27 and M36.

2. Spares – CAF gasket for manway cover.

2. PREVENTIVE MAINTENANCE

Normally deaerator does not require any maintenance except attending to steam leakages from safety relief valves, root valves of instruments etc.

3. OVERHAUL MAINTENANCE

1. Check the condition of trays and spray valves.

2. Check and ensure that the safety valve is operating smoothly.

3. Check the condition of gaskets and replace if necessary.

4. Check and ensure that all the vent lines are clan & through.

5. Clean the storage tank thoroughly.

6. Check the condition of nozzles.

7. Clean all the impulse lines and make them free of debris.

8. Check the condition of all instruments and recalibrate them.

9. Check the condition of level gauge, level transmitter and level controller and ensure that they are in good operating condition.

10. Check the condition of all valve and carry out the lapping of the seat if necessary

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Ums

Binay

APPROVED

Checked and Approved.

Date: 06-Mar-2019


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2

CL. No. BIDDER’S NAME : BHEL

3.00.00 DEAERATOR

3.1.00 Manufacturer BHEL, Hyderabad

3.2.00 Model no. and Number of units - & Two

3.3.00 Type Spray cum Tray

3.4.00 Design and construction standard ASME Sec VIII Div I, 2015 Edition &

HEI 9th Edition 2011 HEI 98

3.5.00 Design pressure Kgf/cm2 (g) 15 & Full Vacuum

3.6.00 Design temperature ( deg. C ) and design vacuum ( mm of Hg )

415 (max) / 0 (min) for Deaerator & 260 (max)/ 0 (min) for St.tank & 760 mm of

Hg

3.7.00 Hydrostatic test pressure Kgf/cm2 (g) 22.5 (for St.tank)

29.64 (for Deaerator)

3.8.00 Shell diameter and thickness

a. Deaerator mm 3000 ID & 32

b. Storage tank mm 4000 ID & 28

3.9.00 Straight length and overall length of shell

a. Deaerator mm 10330 & 12570 Rev-03

b. Storage tank mm 38000 & 40670 Rev-02

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3


3.10.00 Type of dished end and thickness , mm

a) Deaerator 2 : 1 Ellipsoidal 32 (min)

b) Storage tank 2 : 1 Ellipsoidal 28 (min)

3.11.00 Type of storage tank support to mount the Deaerator on floor

Saddle support (Sliding & Fixed)

3.12.00 Number of supports on storage tank 4 Sliding & 1 fixed Rev-02

3.13.00 Distance between supports mm 10000 & 7000 Rev-02

3.14.00 Dimensions of Sparger pipe mm OD 355.6 x 12.7/9.53

3.15.00 Whether anti vortex baffle provided Yes

3.16.00 Mesh size of the reinforced wide meshed strainer provided at the discharge connections from Deaerator storage tank zone

mm NA

3.17.00 Whether the access platform provided is adequate from the operation and maintenance point of view

Yes

3.18.00 Whether oxygen-measuring kit has been provided? No Rev-03

3.19.00 Number of sections the storage tank and Deaerator to be split for shipping it to site.

Storage tank : 3 sections Deaerator : 1 section

3.20.00 Type of manhole provided Hinge type

3.21.00 Dimensions of manhole Ø24”

3.22.00 Number of splash plate provided NA

3.23.00 Numbers of trays provided 720

3.24.00 Number of steam distribution rakes provided NA

3.25.00 Corrosion allowance provided on shell and dished ends

mm 3.2

APPROVED


Date: 06-Mar-2019


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4


3.26.00 Storage capacity at normal water level with a filling factor of 0.66 of the cross-sectional area of the storage tank

m3 315.14 Rev-02

3.27.00 Storage capacity available from normal level to the low-low level

m3 234.5 Rev-03

3.28.00 Water level from centre line of horizontal vessel Mm

a. Normal 508 above

b. Low 100 above

c. Low-Low 1100 below Rev-02

d. High 900 above

e. High - high 1200 above

3.29.00 Type of integral vent condenser provided Direct contact

3.30.00 Spray valves

a. Manufacturer & Model no. Cochrane Environmental System (Crane)

USA, -

b. Type ( Disc Spring or Plunger type) Spring loaded

c. Nos provided 124

d. Control range 10 % - 110 %

e. Pressure drop across the valve Kgf / cm2 0.25

f. Material of construction (indicate ASTM

Standard ) of body, disc, spring and nozzle ) SS316 (A351 CF8M)

g. Residence time Not applicable

h. Droplet size Proprietary

i. Arrangement of spray nozzles within Deaerator Staggered down spray

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Date: 06-Mar-2019


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3.31.00 Protection against inflow of condensate in the steam supply pipe

NA

3.32.00 Whether flashed drain inlet is provided with hardened SS liner

High pressure flashing drain is provided

with disperser arrangement of SS material

3.33.00 Safety Valves

a. Manufacturer & Model No. BHEL, Trichy

b. Type Spring loaded

c. Nos. provided 6 nos

d. Size 8”/10 “- 2 nos. (on Deaerator) & 4 nos.

(on St.tank)

e. Capacity of each at 10% accumulation Kg/hr 110,000

f. Set pressure Kgf / cm2 (g) 14.25 (for 2 nos.), 15 (for 4 nos.),

g. Blow down pressure Kgf / cm2 (g) 13.53, 14.25

h. Materials of construction (indicate ASTM st.)

i. Body and Bonnet cover ASTM A216 Gr.WCB

ii. Disc ASTM A565 Gr.616

iii. Spring ASTM A322-6150

iv. Nozzle ASTM A351 Gr.CF8M

v. Spindle ASTM A276 Gr.410

vi. Sleeve guide / spindle guide / bushing

ASTM A584 Alloy 978

vii. Bolts SA193 Gr.B7

viii. Nuts SA194 Gr.2H

i. Hand lever provided for testing? Yes

APPROVED


Date: 06-Mar-2019


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3.34.00 Stand pipe

a. Material ( indicate ASTM Standard) SA 106 Gr B

b. Nominal diameter & thickness mm Ø168.3 x 10.97 Rev-03

c. Overall length mm 4800 Rev-03

d. Nos. provided 2 nos.

e. Drain & isolation valve provided Yes

3.35.00 Level Gauge Glass

a. Manufacturer & Model No. As per Approved List Of Vendor’s

b. Type Transparent

c. Number provided 4 nos.

d. Measurement range mm 2000.0

e. Isolation, drain, vent & ball check valves

provided ? Yes

3.36.00 Materials of construction ( indicate ASTM Standard)

a. Shell and head

i. Deaerator SA516 Gr.70

ii. Storage tank SA516 Gr.70

b. Splash plates NA

c. Steam distribution rakes NA

d. Trays SA 240 TP430

e. Baffles ( including Antivortex baffle ) NA

f. i Nozzles SA 106 Gr.B (for 16” and below)/ SA516

Gr.70 (above 16”)

ii. Nozzle liner NA

APPROVED


Date: 06-Mar-2019


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7

CL.

No. BIDDER’S NAME : BHEL

g. Restricting orifices SA 240 TP 304

h. Vent pipes SA 312 TP 321

i. Valves ASTM A351 Gr. CF8

j. Bolts SA 193 B7

k. Nuts SA 194 2H

l. Gaskets Non Asbestos

m. Access platform IS 2062 E250 Gr.B

n. Strainer (Screen) NA

o. Impingement plate SA 240 TP 304

3.37.00 Nozzle connections Nos. Size Type

a. Condensate inlet 2 Ø16" BW

b. Feed Water outlet 3 Ø 22" Rev-03

& Ø 16" BW

c. Extraction steam inlet 1 Ø 38" BW

d. Auxiliary steam inlet - - -

e. Pressure equalizing between supply pipe and Deaerator vessel

2 Ø 38" BW

f. Deaerator overflow 1 Ø 8" BW

g. Drain from HP Heaters 2 Ø 12" Rev-03 BW

h. Recirculation from BF pumps 3 Rev-03 Ø 10" Rev-03

& Ø 8" BW

i. Leak – off from BF pumps - - -

j. Vent 6 Ø 6" Rev-03 SW

k. Drain 1 Ø 6" BW

l. Safety valve inlet/ outlet 6 Ø 8"/ Ø 10"

300# / 150# RF

m. Thermo-well 8 Rc1 Screwed

n. Pressure Transmitter 2 Ø1/2”NPT SW

o. Pressure Gauge 2 Ø1/2”NPT SW

APPROVED


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8


3.38.00 Operating Vent Orifice

a. Nos. provided 6

b. Design code / standard NA

c. Steam flow through each orifice at Heater

design condition Kg/hr 75.32

d. Material of orifice plate (indicate ASTM

Specification ) SA 240 TP 304

e. Critical diameter of orifice mm 4.0

f. Diameter of orifice plate mm 92.0

3.39.00 Start-up Vent Orifice

a. Nos. provided

Not applicable;

b. Design code / standard

c. Steam flow through each orifice at heater

design condition Kg/hr

d. Material of orifice plate (indicate ASTM

Specification )

e. Diameter of orifice mm

f. Diameter of orifice plate mm

g. Thickness of orifice plate mm

3.40.00 Weights (Tonnes)

a. Empty 208 Rev-03

b. Normal operating 524 Rev-03

c. Hydrostatic test condition ( flooded weight )

795.000 Rev-02

d. Total shipping weight 208 Rev-03

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9


e. Weight of heaviest single piece during

i. Erection Kg 60000

ii. Maintenance Kg 6.0 (Tray assembly inside Deaerator Heater)

3.41.00 Shipping Dimensions (mm) piece Heater

Feed Storage tank

Sec-I Sec-II Sec-III

Length 12750 14110 12450 14110

Breadth 3450 4100 4100 4150

Height 3750 4650 4650 4650

No. of pieces complete Deaerator shall be shipped

4 sections

APPROVED


Date: 06-Mar-2019


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��

!"�#$��%#��&��'

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1. Refer comments on Mechanical strength calculation of Deaerator and Thermal & hydraulic calculation of

deaerator and revise all dimension and thickness of various section of dearator and storage tank. All the

data can be approved after finalisation of sizing calculation.

BHEL Clarification: Noted.

2. BHEL shall provide the basis for Design Temperature 260 deg C

BHEL Clarification: As per design code HEI, The Minimum design temperature should not be less than 205

deg.c or saturation temperature of Design pressure whichever is higher. Saturation temperature

corresponding to design pressure is 197.36. Hence it meet both the condition.

3. S.No 3.7 Hydrostatic test pressure, BHEL shall provide the basis for 22.5 kg/cm2

BHEL Clarification:

For Heater:

A. Hydrostatic test pressure shall be = 1.3 *Design pressure *Lowest stress ratio.(As per ASME UG-99).

=1.3*15* (Stress value at room temp./Stress value at design temperature) = 1.3*15*(1406/925)=29.64

kg/sq.cm(g) .

B. Hydrostatic test pressure shall be = 1.5 *Design pressure (As per IBR)=1.5*15=22.5 kg/sq.cm(g).

Higher of A & B is 29.64 kg/sq.cm(g)

For Storage Tank:

A. Hydrostatic test pressure shall be = 1.3 *Design pressure *Lowest stress ratio.(As per ASME UG-99).

=1.3*15* (Stress value at room temp./Stress value at design temperature) = 1.3*15*(1406/1406)=19.5

kg/sq.cm(g) .

B. Hydrostatic test pressure shall be = 1.5 *Design pressure (As per IBR)=1.5*15=22.5 kg/sq.cm(g).

Higher of A & B is 22.5 kg/sq.cm(g)

4. S.No 3.8 Shell dimensions and thickness, shall be updated based on the final resolution on the sizing

Calculation.

BHEL Clarification: Length of Storage tank has been increased from 33.5 to 38 m.

5. Refer comments on GA of Deaerator and increase nos. of support

BHEL Clarification: No. of supports increased from 3 to 5.

6. Unsupported length considered in strength calculation is 9m, Check.

BHEL Clarification: Unsupported length given in the Strength calculation is the length between two

Stiffeners.

7. Refer comments on calculation for storage volume and revise.

BHEL Clarification: Revised.

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Date: 06-Mar-2019


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8. With this flow and size of safety valve, velocity is comming very high. Either increase nos. of valve or

increase size.

BHEL Clarification: SRV has been sized as per HEI. We confirm that data indicated is in order.

9. Above 14" shall be SA516 Gr.70.

BHEL Clarification: For the nozzle size up to 16”, we use Seamless pipe. As per BHEL standard practice.

APPROVED


Date: 06-Mar-2019


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This Drawing is printed from Engineering Digital Archive System (EDAS).Therefore signatures are not essentially required.

Nov Thu 22 10:29 2018

APPROVED


Date: 17-Dec-2018



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Dec Thu 20 07:40 2018

FIO

FOR INFORMATION ONLY

Date: 17-Jan-2019



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FEED HEATING SYSTEM

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Description Operation

And Maintenance FEED HEATING SYSTEM

Bharat Heavy Electricals Limited

IMPORTANT READ BEFORE INSTALLING

The instructions given in this manual are intended to aid you in the operation, performance, and preservation of your new feedwater heaters. While everything discussed in this instruction manual is important, we have selected this page to emphasize several instructions that MUST BE FOLLOWED when installing or operating these feedwater heaters. OPERATING AIR LINES MUST BE CONNECTED AND WORKING. DO NOT MANIFOLD OR CASCADE THESE VENTS. ALL PARTS PAINTED YELLOW MUST BE REMOVED PRIOR TO TESTING OR OPERATING. CHECK THE TIGHTENESS OF ALL PERMANENT PLUGS AND COVERS PRIOR TO PRESSURING THE HEATER. LOWE LIQUID LEVELS DURING OPERATION MUST BE AVOIDED. BHEL MUST BE NOTIFIED PRIOR TO PERFORMING ANY WARRANTY WORK. TO PREVENT POSSIBLE EQUIPMENT DAMAGE AS A RESULT OF FEED WATER BY-PASSING, READ THE FEEDWATER BY-PASSING SECTION OF OPERATION.

A PRESSURE GAUGE ON A FEED WATER HETAER INDICATES THE VESSEL IS FILLED WITH NITROGEN GAS FOR SHIPPING. ALL PERSONNEL MUST BE CAUTIONED NOT TO PUT THEIR HEAD INTO VESSEL OPENINGS. NITROGEN IS COLORLESS AND ODORLESS AND SUFFOCATION COULD TAKE PLACE WITHOUT THE SENSES PROVIDING AN ALARM. HOT CONDENSATE MAY REMAIN IN THE TUBES FOR SOME TIME AFTER THE CHANNEL IS DRAINED. PROPER CAUTION IS TO BE TAKEN WHEN ENTERING THE CHANNEL OF A HOT FEEDWATER HEATER. THE DESUPERHEATER BYPASS CONNECTION (WHEN PROVIDED-SEE G.A. DRAWING) MUST BE UTILISED FOR OPERATING LOADS IN EXCESS OF CONDITIONS SHOWN ON SPECIFICATION SHEET. ANY SIGNIFICANT INSTALLATION, OPERATION OR MAINTENANCE PROBLEMS SHOULD BE REPROTED TO :

SENIOR MANAGER (FSS) BHEL

HYDERABAD-502032

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OPERATION Starting, operating and shutting down of a feedwater heater requires specific instructions, with emphasis on load limitations, as well as the order of start-up and shut-down. The plant operating instructions and the feedwater heater Setting Plant drawings, specification sheets, and nameplates are to be reviewed prior to operating these feedwater heaters. The following are precautions that should be reviewed and recognized when operating these feed water heaters. START-UP Feedwater heater operation should not be undertaken if any of the protective devices are known to be faulty. Feedwater heaters are not to be operated at fluid temperatures higher than those shown on the specification sheet. Feedwater heaters must not be subjected to abrupt temperature fluctuations. Hot fluid must not be introduced rapidly when the heater is cold, nor cold fluid when the heater is not. Prior to opening the feedwater valve, the channel start-up vents are to be opened and remain open until all passages have been purged and feed water begins to discharge.

To remove air from the shell side of a heater which does not operate under vaccum, the shell start-up vent valves should be opened prior to the admission of steam to the feedwater heater. The extraction lines must be free of all condensate to prevent damage to the heater internals by slug flow. When the drains outlet valve is opened, the shell start-up vent valves are to be closed and operating air vent valvesare to be opened. Continuous venting of air and other noncondensables is assured by keeping the shell operating vent valves open. On initial plant start-up horizontal or vertical channel up feedwater heaters, having integral drain coolers, the liquid level is to be keep just below the high level alarm point. This will avoid the possibility of flashing at the subcooler inlet and approach temperature (difference between drain coolet outlet and feedwater inlet temperatures should be monitored. Approach temperatures in

excess of 8°C indicate the probability of flashing at the sub-cooler inlet. In this case, the liquid level should be raised until the drains approach temperature approached the specification sheet value.

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WHAT IS A FEEDWATER HEATER? A feedwater heater is a special form of a shall and tube heat exchanger designed for the unique appliation of recovering the heat from the turbine extraction steam for preheating the boiler feedwater. Its principal parts are a channel and tubesheet, tubes, and a shell. It can be designed for either low or high feedwater pressures and may be installed either horizontally, vertical channel down, or vertical channel up. The tubes may be either bent tubes or straight tubes. Feedwater heaters are defined as a high pressure heaters when they are located in the feedwater circuit upstream from the high pressure feedwater pump. Low pressure feedwater heaters are located upstream from the condensate pump which takes its suction from the condenser hotwell. Because the discharge pressure from these pumps differs greatly, the physical and thermal characteristics of high and low pressure feedwater heaters are vastly different. Typically, low pressure feedwater heaters and designed for feedwater pressure-between 15 AND 50 Kg/cm2. High pressure heaters range from 100 50 Kg/cm2 for nuclear heat sources to 335 50 Kg/cm2 for super critical boiler. Regardless of the actual design pressure, the classification depends upon the cycle location relative to the feedwater pumps. The design pressure is specified sufficiently high so as to not over pressure the channel side of the heater

under any of the various operating conditions, particularly at pump shutoff. Heaters may be installed in any of the three orientations mentioned above. Additionally, low pressure heaters may be installed in the condenser transition between the turbine exhaust opening and the condenser tube field. Each feedwater heater bundle will contain from one to three separate heat transfer areas or zones. These are the condensing, desuperheating and subcooling zones. Economics of design will determine wheat combination of the three is provided in each heater. The desuperheating zone is a separate coutnerflow heat exchanger containing within the heater shell. This zone�s purpose is to remove superheat present in the steam. Because of the high steam velocities employed, condensation within the desuperheating zone is undesirable. The sub-cooling zone, like the desuperheating zone, is another separate counterflow heat exchanger whose purpose is to subcool incoming drain and steam condensate.

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PRE-INSTALLATION STORAGE OF FEED WATER HEATERS

Caution : A pressure gauge on a

feedwater heater indicates the

vessels is filled with nitrogen

gas for shiping. All personnel

must be cautioned not to put

their head into Vessel

openings to inspect the

interior. Nitrogen is colorless

and odorless and suffocation

could take place without the

senses providing an alarm.

The feedwater heaters should be

thoroughly inspected for shipping damage

as soon as they arrive. Heaters with an

internal nitrogen atmosphere have

pressure gauges to show internal

pressure on both shell (steam) ad tube

(water) side. Heaters are shipped under

0.7 Kg/cm2 (g) nitrogen pressure. If the

nitrogen pressure has fallen below 0.35

Kg/cm2 (g) during shipment, it should be

restored to Kg/cm2 (g).

Heaters should be stored on

cribbing and not a contact with the

ground. Horizontal heaters should rest on

their supports. Vertical heaters, with no

supports, should be checked to prevent

turning. The end of the vessel with the

feedwater nozzles should be at least 25

mm lower than the other end to prevent

condensate from lying in the tubes.

Drainage points such as plugs or nozzle

covers, should be at the lowest point.

Heaters shipped without a nitrogen

blanket should nozzle cover, or plugs

loosened to permit drainage. An

unpressurised heater will breathe during

daily temperature changes and moisture

taken in will condense. This condensate

must be given a way to drain.

Heaters with a nitrogen

atmosphere, once positioned, should be

�blown down� by loosening a plug or

nozzle cover at the low point and allowing

any condensate to escape from each side

of the heater. Caution is to be exercised

when loosening the plug or cover,

because the feedwater heater is

pressurized. Personnel should not have

any portion of their body in direct line with

the plug or cover. The opening should be

immediately resealed. The loss of

nitrogen will be very slight.

Nitrogen blanked heaters should

be inspected on a regular basis. If the

pressure falls below 0.2 Kg/cm2 (g), it

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should be restored 0.7 Kg/cm2 (g). Minor

leaks can be stopped, by a slight uniform

tightening of cover bolts or by tightening

the threaded bar plugs in couplings.

If uniform tightening of gasket

cover bolts will not stop a leak, the gasket

must be replaced to permit restoration of

the nitrogen seal. To minimize the time a

vessel is open, all tools and material

should be available before starting the

work.

Caution : Before beginning to remove

the bolts holding a gasket

cover, bleed the nitrogen

pressure down to �zero�. Do

not attempt to remove a cover

or bag plug from a pressurized

vessels.

The recommended gasket material

is 3 mm thick compressed asbestos

service sheet. The gasket should be cut

to fit just inside the bolt circle. If the

nozzle cover has a coupling in it, cut a 25

mm hole in the gasket to match that

location.

While the cover is removed,

inspect it and the nozzle end for any

surface condition that could cause a leak.

Replace the cover and new gasket

as quickly as possible to minimize

nitrogen loss. Secure the hold down bolts

finger � tight and pressurize the vessel

with nitrogen. Allow the gas to flow

around the loose cover and seep out air

admitted during the change. A five minute

flow should restore the nitrogen

atmosphere.

Tighten the cover uniformly in the

conventional star pattern. Do not

overtighten and risk cutting the gasket.

Retest with a soap solution or a

commercial solution.

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INSTALLATION INSTRUCTIONS

Feedwater heater are shipped completely assembled and ready for installation on the purchaser�s supports. The heaters musr be installed as shown on the G.A. drawing in a true verticle horizontal plane.

SETTING HEATERS

All heaters are to be lifted into place. Roller supports when provided can be used for rolling the heaters into place after lubricating the wheels and moving the heaters with caution, no sudden starts or stops.

The lifting lugs are designed fro an impact loading of 2g. We would suggest that you do not exceed and angle fo forty five degree s(45°) off the vertical along the longitudinal heater centerlines.

Proper rigging must be used in lifting assembled feedwater heaters. Fedwater heaters are usually much heavier than pressure vessels of comparable dimensions; therefore, weights should be secured from the setting plan drawings.

The fixed supports have been designed so that shims have to be used to obtain the proper elevation and orientation.

Nuts for foundation bolts installed in slotted support holes are to be loosened to allow free expansion of the shell.

PIPING CONNECTIONS

All parts painted yellow are to be removed prior to operating the feedwater heater. Remove the shipping covers and plugs immediately prior to connection of the piping.

It is not necessary to remove the shipping cover nuts that are welded to the piping connections. However, if it is desirable to remove these nuts, do so by grinding the weld. Do not �knock-off� the nuts.

Before connecting the piping, inspect all openings in the feedwater heated for foreign material.

When nitrogen blanketing has been applied to the feedwater heater all personnel must be cautioned not to visually inspect the internals by projecting their heads through the openings. Nitrogen is colorless and odorless and suffocation could occur without the human senses providing an alarm. The entire system should be clean and free of foreign objects before starting operation. Do not expose the feedwater heater internal to moisture or harmful contaminants.

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All of the connections on the G.A.

drawings must be utilized for the purpose

intended I unless otherwise approved by

BHEL Engineering Department. All

operating vents must be I connected and

opening during operation of the feedwater

heater.

Prior to installing the safety relief

valves, verify that the valve set pressure

is indentical to the design pressure on the

feedwater heater nameplate.

CORROSION PROTECTION

On feedwater heaters where

nitrogen blanketing or other corrosion

protection has been applied, it is

recommended that the heaters be left

sealed as long as possible prior to the

installation of the piping. After piping is

complete, carbon steel tubed heaters

should be immediately protected with a

nitrogen blanket or other suitable means

of protection against corrosion.

ALTERATION OR REPAIRS

Any alterations or repairs that may

become necessary during installation,

testing or operation, should be made

under BHEL direction and in accordance

with BHEL�s procedure.

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HYDROSTATIC TESTING

The hydrostatic test pressure of closed feedwater heaters are stated on each heater�s nameplate and on the specification sheets included in this instruction manual. Under no circumstance is the hydrostatic test pressure to be exceeded.

When a feedwater be hydrostatically tested at a pressure approaching the design pressure stamped on the heater nameplate, the safety relief valves must be gagged or blanked off. Safety relief valves should not be lifted under hydrostatic test conditions.

CODE INSPECTION

When hydrostatic testing is conducted to demonstrate acceptability of repairs performed on pressure parts of a feedwater heater, it is recommended that these tests be witnessed by the owner�s Authorised inspector.

TESTING PRECAUTIONS

A tight sealing isolation valve designed for differential pressure equal to the hydrostatic test pressure, or a piping blank off, is required in extraction lines when the shellside of a feedwater heatetic tested.

During filling, start-up vents must be opened and remain open until all

passages have been purged of air or nitrogen and are completely filled with fluid.

After completely filling the chamber to be tested and purging it of air or nitrogen, the start-up vens are to be closed.

Pressure to be applied a steady rate. In no case should the vessel be subjected to a sudden pressure surge. It is commended that a relatively small capacity pump be used to apply hydrostatic test pressure.

DRAINAGE AFTER HYDROSTATIC TEST

Following hydrostatic testing, the feedwater heaters are to be derained. It is preferred in most cases, and essential in the case of carbon steel tubed heaters, that they be dried and nitrogen blanketed following drainage.

Feedwater heaters are pressure tested before leave the shop in accordance with ASME Code requirements. However, normal yielding of gaskets may occur in the interval between testing in the sop and installation at the job site. Therefore all external bolted joints may require retightening after installation and, if necessary, after the heater has reached operating temperature.

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GENERAL PERFORMANCE

Feedwater heater operating conditions and performance should be checked regularly against the values stated on the specification sheet provided for each heater.

Any significant deviation of heater performance from that specified should be immediately reported to BHEL-FSS Department. The prompt reporting of any suspected performance problem is to be best guard against the possibility of damage of the feed-water heater. A detailed performance report should include actual values for all of the flows, temperatures, and operating pressures listed on the specification sheet.

The failure of a feedwtaer heter to perform satisfactorily may be caused by one or more factors, such as :

(1) Air or non-condensable gas blanketing resulting from improper piping installation or lack of suitable venting.

(2) Flooding resulting from inadequate drainage of condensate.

(3) Operating conditions differing from design conditions.

(4) Tubing failure.

(5) Maldistribution of flow.

Abrupt flooding, unusual noise or loss of feedwater temperature rise can indicate tubing failure. If such a condition occurs, the heater must be removed from service as quickly as possible. Tube failure tend to have a chain reaction effect; impingement on adjacent tubes can cause additional failures.

VENTING

Proper venting is necessary on feedwater heaters. All operating air vent connections must be piped to permit continuous venting.

The venting system in a feedwater heater is designed to assure that all points where noncondensable gases could collect are vented. Failure to utilize all of the operating air vents can lead to corrosion damage and/or loss of performance due to air blanketing.

Vents lines of heaters operating at a different shell pressure must not be piped to a common manifold. Failure to run individual vent lines from each heaters has resulted in inadequate or no venting of a heater operating at a lower shellside pressure than other heaters piped into a common manifold. Also, tubing adjacent to an air removal connection has failed due to erosion caused b y blow back of condensed vapor fed into the heater from a manifold which also served a heater operating at a higher shellside pressure.

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Multiple operating air vent connections on the same heater can be manifold downstream from the vent orifices and exhaust through a single vent pipe. The manifold must be sized to handle the total flow from the vents and discharged into a pressure lower than the vent pressure.

A sharp distinction must be drawn between start-up vents and operating air vents, as identified on the G.A. drawings. Start-up vent must be closed during on-the-line operation, and IN NO EVENT are start-up vents to be piped up to a manifold serving the operating air vents.

Vents should not be cascaded. The reason for venting is to remove noncondensable gases. Cascading of vents defeats this purpose by imposing on each succeeding heater in the cascade a load for which the vent system is not designed.

Vent flow controls is best accomplished through the use of properly sized sharp-edged orifices constructed of stainless steel or other suitable erosion/ corrosion resistant material.

When internal vent orifices are provided, this will be indicated on the G.A.drawings and no additional orifices are to be used.

Vent piping should be scized to assure that the back pressure, at the discharge of the vent orifices, is no greater tha, 50% of the shell side operating pressure. When there is no desuperheating zone in a given heater,

this shellside operating pressure may be considered as equal to the steam inlet pressure. If a desuperheating zone is employed, deduct 0.35 Kg/cm2 from steam inlet pressure to obtain the approximate shellside operating pressure for the purpose of sizing vent piping. Note that the intent is to control the operating air vent flow by assuring critical flow through the vent orifices.

Isolation valves in vent piping should either be locked in the open position or some other suitable means provided to assure that such valves cannot be closed during normal operation.

FEEDWATER BY-PASSING

Serious problems can result form indiscriminate by passing of feed water heaters.

The removal of the final feedwater heater should not affect the other heaters in the cycle. The effect on load limitations by removing the final heater must be reviewed with the turbine and steam generator suppliers.

A feedwater heater may be severely damaged by erosion and/or vibration, if it is operated for any significant period of time with the next lower heaters feed water flow by-passed on to the next higher heater. This next higher will come close to making up the duty of both heaters. This single heater

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Will tend to draw a total amount of extraction steam approximately equal to the flow to both heaters.

In the case of heaters with desuperheating zones, the increased steam load due to by-passing the previous heater can cause an excessive pressure drop in the desuperheating zone, which in turn can cause condensation. The condensate flowing at high velocity can lead to severe tube erosion.

Excessive steam flow to a heater, resulting from by-passing the feed water side of the previous heater, can result in:

a) Localized high velocity lead to vibration of the tubing.

b) Flows which cannot be adequately handled by the drain control valve.

c) Condensation in the desuperheat zone and high velocity impingement.

CAUTION : To prevent possible damage to the turbine, the bypassing of a feedwater heater should not be undertaken without consulting the turbine supplier.

SYSTEM UPSET CONDITONS

The feed water heater will operate satisfactorily under the following system upset conditions. Better life can be obtained by limiting such operating modes to short duration�s.

a) H.P.heaters in operation only above 60% load.

b) Any one L.P.heater out of service. L.P. drain cooler and L.P. heater 1 work together and have common by-pass.

c) Any H.P. heater out of service.

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LIQUID LEVEL

A check of the feedwater heater liquid level should be a standard operating procedure. Low levels must be avoided.

A low liquid level in the feedwater heater occurs when the liquid level indicates below the normal liquid level.

Low level opeation of horizontal or vertical channel up heaters results in flashing at the subcooling zone inlet. This flashing can lead to erosion failure of the tubing. On a carbon steel tubed feedwater heater, it is extremely important that flashing at the subcooler inelt does not take place since this type fo tubing is more susceptible to erosion than others.

Evidence of low level operatin is obtained by examining subcooler performance. If the subcooling zone approach temperature (shell drains outlet temperature minus feedwater heater inlet temperature) is close to the normal rted value, there is reasonable assurance that the level is adequate. If the drain approach is high, operation is at less then desirable level and raising of the liquid level is required.

Generally, if vapour is by-passing into the subcooling zone inlet, the noise level in the drains outlet piping is relatively high and is often accompanied by noticeable movement is the drains piping.

SHUT � DOWN

In order to avoid damage from freezing, water must be prevented from remaining in a heater exposed to freezing conditions. It has been demonstrated that tubes in a horizontal position will not drain sufficiently by gravity alone to prevent freezing damage.

When taking an individual feedwater heater out of service for an extended period of time, provisions should be made to protect the heater internals from corrosion and pitting. This can be accomplished by blanketing both the steam and feedwater sides with a positive pressure of nitrozen, or another inert gas. When it is not possible to provide an inert gas blanket and freezing conditions will not be encountered, both sides of the heater should be flooded with oxygen-free condensate.

Note : If may be necessary to adjust the level control on the feedwater heater whose drains normally flow to the shut-down heater to maintain the steam seal on the drain cooler inlet.

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FIELD WELDING

If it becomes necessary to perform manual welding on a pressure vessel in the field, the comments listed below should observed.

CERTIFICATION

All welding must be performed using a procedure qualified in accordance with Section IX of the ASME code.

Welders must be certified to the welding process involved in accordance with Section IX of the ASME code.

When welds are to be made on a code stamped vessel, an authorized Inspector should be contacted to review the procedure and witness the welding and any tests that are performed.

GENERAL PRECAUTIONS ON WELD MATERIAL APPLICATION

Do not apply carbon steel electrodes or filter wire to high nickel material such as stainless, Inconel or Monel.

Do not apply stainless steel to Inconel, Monel or any copper base alloy.

Proper preheat, dryness and cleanliness of the welding area are very important when welding. This is particularly true with tube-to-tubesheet welds.

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BOLTED CONNECTIONS

ASSEMBLY

1. All bolted connections are to be tightened uniformly and in a diametrically staggered pattern as shown on the sketch below. This will ensure a uniform stress over the entire gasket surface. The procedure to use in tightening is :

A. Tighten up all bolts hand tight. B. Take up bolts, one flat at a time, in pattern shown below. C. Continue until the bolts are torqued to the value given in the table below:

RECOMMENDED TORQUE VALUES

NOMINAL NUMBER TORQUE mm In (25.4 MM/IN) Ft.LBS KG-M

15.7 5/8 11 120 16

19.0 3/4 10 200 27

22.2 7/8 9 320 44

25.4 1-0 8 420 59

28.6 1-1/8 8 710 100

31.7 1-1/4 8 1,000 140

34.9 1-3/8 8 1,360 190

38.1 1-1/2 8 1,600 220

41.27 1-5/8 8 2,200 310

44.4 1-3/4 8 3,000 420

47.6 1-7/8 8 4,000 565

50.8 2-0 8 4,400 620

57.1 2-1/4 8 6,360 890

63.5 2-1/2 8 8,800 1240

69.8 2-3/4 8 11,840 1670

76.2 3.0 8 15,440 2180 NOTE : Torque values are based on steel bolting, well-lubricated with a heavy

graphite and oil mixture.

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2. If the bolted connection leaks, the nuts can be tightened in the pattern outlined above, one flat at a time. The spacing between the flanges must be equal throughout the tightening process. This will assure the gasket surface will not be distorted.

3. If a connection continues to leak, it must be disassembled and examined for the following :

A. Indication of leak path, such as a gouge across the gasket surface.

B. Evidence of an interference between the mating connections.

C. Evidence of distortion of out of roundness of either of the mating gasket surfaces. This usually best checked by measuring the gasket compression every 45 deg around the gasket itself. Thickness measurements should also be taken close to both the I.D. and O.D. of the compressed portion of the gasket to check against any possible rotation of the flange during bolt tightening.

D. Evidence of bolt diameter reduction, or �necking�,

which would indicate an overstressing of the bolts.

4. In order to insure that all bolted flanged joints remain tighten, such joints should be tightened uniformly immediately after the heater has been placed in service for the fist time and again after the heater has been operated at full load for the first time. It is recommended that periodic checks be made during the first six months of operation to insure proper tightens of all bolted joints.

DISASSEMBLY

1. Protection must be provided to assure that, on completion of bolt removal, parts will not fall free or shift, possibly leading to injury of personnel or damage to equipment.

2. All mating flanges should be adequately match-marked before disassembly is started.

3. Bolts are to be loosened in the reverse of the tightening pattern shown above.

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GASKETS

1. Gasket selection should be in accordance with original design.

2. The use of non-hardening compound is recommended to aide in holding the gasket in place during bolt-up. The use of masking tape or a hardening compound is not recommended.

3. Gasket surfaces must be inspected for cleanliness and

absence of scratches, erosion etc., before gaskets are installed.

4. If there is any evidence of damage on gasket surfaces, or if there is any question with regard to gasket material and/or type, this should be referred to BHEL-FSS Department.

5. If there is any evidence of damage on gasket surfaces, or if there is any question with regard to gasket surfaces, the flat side of the gasket muse be in contact with the nubbin.

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LOCATING TUBE FAILURES

To determine the probable causes of failure, it is essential that the exact location of each failure be known.

This instruction gives a method of locating the point of failures in a feedwater heater tube. Although other means may be employed, it has been our experience that the system described represents a practical procedure for making an accurate determination of the location of a tube failure.

Caution : Hot condensate and vapour may remain in the tubs for some time after the tubeside is drained. This may stay hot, if the turbine is in operation and steam leaks through the extraction isolation valve. Proper caution is to be taken when entering the tubeside of a hot feedwater hetaer.

When collecting data on tubing failure, the following minimum information must be recorded:

1. BHE Serial Number. 2. The pass in which the failure

occurred (feedwater inlet or outlet.)

3. Tube row, counted from pass plate.

4. Tube number, counted from the left when facing the tubesheet.

5. Distance of the failure back from face of tubesheet.

6. Length of failure, where possible. 7. Date of investigation.

Data on failures is to be forwarded to BHEL, attention Field Support Services Department.

The face of the tubesheet, the tube ends and the inlet pass tube inside surfaces are to be visually examined using a bright light, from a distance of approximately one foot. This examination should disclose any pitting, �bug holes� or other indications of damage.

If any tubes have been previously plugged, they must be checked to assure no leak paths have disclosed around the plug.

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PROBE FOR INVESTIGATING FAILURES IN TUBES :

The probe shown below is to be used to locate the tube leak.

LOCATING TUBE FAILURES :

1. Approximately 0.2 Kg/cm2(g), or nitrogen, is to be applied on the shellside. The face of the tubesheet is to be traversed with the hand to detect any gas flowing from the open ends of a tube with a failure. Using rubber stoppers, seal off both ends of each tube that is discharging air or nitrogen. If the heater is hot, air or nitrogen admitted to the shell will blow out of the ends of failed tube at an elevated temperature and personnel must be cautions when working close to the tubesheet.

Caution : Remove all rubber tube prior to increasing the shellside pressure above 0.2 Kg/cm2(g).

2. If no tube leaks are located, slowly increase the pressure to a maximum of 80% of the nameplate shell design pressure, but not a exceed 7Kg/cm2g.

If necessary to increase the pressure beyond 0.2 Kg/Cm2g keep personnel at a safe distance while the pressure is being increased.

3. Using the probe shown, probe each leaking tube to determine the location of the leak as follows:

Insert the probe into the leaking tube. This will seal off gas flow the insertion end of the tube until the probe has been inserted far enough to reach the point of failure. As soon as the probe crosses the failure, gas will blow out of the plastic tube is to be immersed in water. An increased flow of bubbles in the water indicates that a leak has been located.

If the failure is very small, air will stop blowing through the other end of the feedwater heater tube when the failure has been passed by the probe seal. If the failure is

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a long split, air will continue to blow out of both ends until the probe has been advanced across the other end of the failure. The probe is to be moved back and forth slowly to identify both ends of the failure. The length of the failure is equal to the distance moved, minus 50 mm.

Once a failure has been located the depth

Where tubes have failed directly behind the tubesheet, particularly attention should be given to the tube-to-tubesheet joint.

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WATER BOX COVER (MULTILOCK TYPE) REMOVAL/FIXING PROCEDURE

A) COVER REMOVAL PROCEDURE :

1. Cut the torus ring (Pos. No.7) weld by gas cutting and remove the torus ring from channel & cover (Pos.No:2)

2. Unfasten the Backing ring screws (position No:6)

3. Use suitable fixture to push the cover (wt.700 Kgs.) (pos.No.2) little inside, In order to facilitate removal of backing ring pos. No:5)

4. Remove the backing ring pos. No.5

5. Remove the shear key split ring pos. no.4 (In six pcs) by using the slot in the ring.

6. Remove the cover pos. no.2 by withdrawing the fixture.

7. Remove the pass partition plate by unfastening the fasteners required for tube plugging.

B) FIXING THE MULTILOCK ARRANGEMENT.

1. Fix the pass partition plate by fastening the fastners.

2. Place the cover pos. no.2 inside the channel by using suitable fixture.

3. Place the shear key ring (in six pieces) inside the groove in the channel.

4. Place the backing ring (pos. no.5) in position and withdraw the jack.

5. Fasten the screws (pos.no.6) in the backing ring through end cover. Tighten the screws.

6. Weld the torus ring with cover and the channel. Run 1st layer with TIG.DPT/MPT check the weld.

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PROCEDURE FOR TUBE FLUGGING

Tube Plugging :

If any tube falls, both ends of the tube must be plugged with plugs. The other end of given tube will be exactly opposite the given tube end on the other side of the partition plate. A simple way to check is to blow a jet of air or water into the given tube end and note the other end of tube through which it returns.

Proceed as follows for plugging of leaky tube:

a. Remove multilock channel cover.

b. Remove the pass partition plate.

c. Pressure the steam space (shell side) by air/water and mark leaking joints.

d. Drill/remove tube upto a depth of 6 mm on both ends of leaking tube.

e. Make plugs of carbon steel material (SA 105, IS 2004, CL.III etc., or from boiler quality plate material).

f. Before the insertion into the tube hole, both the plug and tube hole are to be thoroughly cleaned with acetone or equal solvent and wipe with clean cloth.

g. Put the plug in position (flush with tube end) & weld.

h. The plugs shall be covered with layers of weld metal until they are flush with the face of the tube sheet. Each layer shall be carefully cleaned and inspected before the subsequent layer is deposited by dyepenetrant.

i. Exceptional care shall be exercised to avoid any burn through the ligaments of adjacent tube joints.

j. Before closing the water box, the effectiveness of plugging shall be checked for by pressuring the shell with air at 10 Kg/Cm2. The soap solution shall be applied to the face of the tube sheet for air bubble test. If any leaks are revealed, the leaks shall be repaired.

k. After successful plugging, the partition plates shall be replaced and channel cover reassembled.

i. The heater shall be hydraulic tested to design pressure on tube side.

k. The heater can be returned to service after ensuring that there are no further leakage�s.

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B. TUBE PLUGGING BY USING A TAPPERED DRIVE PLUG :

(For LP hearers, drain cooler and gland steam condenser)

i. Select the suitable tapered plug from the following table.

Tube material Plug material Tube size OD x THK mm

Plug size dia �A� mm

Dia �B�

mm

Stainless steel CS SAS 105 19.05X0.889 17.0 20

ii. Both the inlet and outlet end of the leaking tube is to be renamed as required to assure a tight fit.

iii. Clean both ends of the tube to a depth of 60 mm.

iv. Drive the tapered plug into the tube ID. A properly seated plug will ring when sruck.

v. TESTS

a) Air and soap leak test the plug(s) by applying air or nitrogen at 1Kg/Sq. cm (g) on the shell side.

b) Hydro test the shell side at a pressure approximately 10% below the shell side design pressure. Hold the pressure for a least 4 hours and check for any droplets or weepage.

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TABLE � 1

DETAILS OF TUBE PLUGGING

Sl.

No.

Tube Sheet

& Overlay Material

Tube

Matel.

Plug

Mate-

Rial

Weld-

ing

process

Filler

Wire

Material

Size

(Z mm)

Volts

(V)

Current

(Amps)

Gas Flow

Rate

Cu ft/hr

1. Carbon Steel Overlaid with

Stainless steel

SSTP

304

AA105

Carbon

Steel

Rounds

TIG ER 209

Or Equi-

valent

2.4 16-20 75-120 12-20

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CL. No. BIDDER’S NAME : BHEL – Hyderabad

4.00.00 HIGH PRESSURE HEATERS: HP HEATER 7A/7B HP HEATER 8A/8B HP HEATER 9A/9B

4.01.00 Manufacturer BHEL, HYDERABAD

4.02.00 Model no. and Number off 1 Each 1 Each 1 Each

4.03.00 Type and arrangement U-Tube Horizontal

4.04.00 Design and construction standard ASME SEC VII DIV 1 2015 Edn.. & HEI 9th Edn

4.05.00 No. of shell passes 1 1 1

4.06.00 No. of tube passes 2 2 2

4.07.00 No. of zones 3 3 3

4.08.00 Heat transfer surface area

a. Drain cooling zone m2 279.24 294.91 83.49

b. Condensing zone m2 1057.33 1151.5 1010.19

c. Desuperheating zone m2 120.92 219.11 166.03

d. Ineffective area m2 NIL NIL NIL

e. Total area (provided) m2 1617.4681 1866.2825 1435.003

f. Total extra surface provided m2 159.9781 200.76 175.293

4.09.00 Heat transfer data under design (guaranteed) condition :

a) Heat (Kcal/Hr.) transferred x 106 Reference HBD No. – BD1033-ES EN TPEC PP-T0103 R9

i. Drain cooling zone 5.939 8.926 1.397

ii. Condensing zone 22.198 40.825 20.685

iii. Desuperheating zone 2.102 5.547 4.208

iv. Total Heat Transferred 30.24 55.299 26.779

b) LMTD (deg C)




c) Overall heat transfer coefficient ( Kcal/hr- m2 deg C)


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d) Tube side fouling factor as

applied to each heat transfer zone

hr- m2 deg C / Kcal 0.0000596 0.000061035 0.0000616496

e) Outer tube surface fouling

Factor Heat for

i. Drain cooling zone hr- m2 deg C / Kcal 0.0000614448 0.0000614448 0.0000614448

ii. Condensing zone hr- m2 deg C / Kcal 0.0000 0.0000 0.0000

iii. Desuperheating zone hr- m2 deg C / Kcal 0.0000614448 0.0000614448 0.0000614448

f) Velocity through tubes m/sec

1.88 2.090 2.3

g. Drain level in heaters (Below the shell center line )

i. Normal mm 630 630 630

ii. Maximum mm 114 114 114

iii. Minimum mm 708 708 708

iv. Clearance between the maximum operating level and the bottom of the tube bundle

mm 516 516 516

4.10.00 i. Velocity through tubes at maximum flow. (HBD No.-PE-DC-381-100-N208 R-00)

m/s ~ 2.29 ~ 2.30 ~ 2.31

ii. Tube side pressure drop at maximum flow.

Kg / cm2 1.0 1.3 1.2

4.11.00 Maximum noise level produced during operation (dBA)

85 85 85

4.12.00 Tubes

a) Type of tube provided (welded

or seamless) Welded U-Tubes to Specification SA213 TP304N

b) Total no. of U-tubes 1673 1673 1673

c) No. of extra tubes provided 10 10 10

d) Effective length of U-tubes

(Total) mm 20508 31067 26555

e) Total straight length of one leg

mm 9800 11300 8700

f) Outside diameter mm 15.875 15.875 15.875

g) Wall thickness before

Bending (Avg.) mm 2.2 2.65 2.66

h) Minimum thickness at bend after

bending mm 12 12 12

i) Maximum carbon content in

tube % 0.05 0.05 0.05

j) Design pressure kg/cm2(g) 390 & F.V 390 & F.V 390 & F.V

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k) Design temperature deg C

i) Desuperheating zone 235 290 315

ii) Other zones 235 290 315

l) Hydrostatic test pressure Kg/ cm2(g) 585 585 585

m) Type of tube-to-tubesheet

Joint Roller expanded and strength welded

n) Tube pitch Mm 20.64 20.64 20.64

o) Type of tube pattern Triangular

p) Shell / tube bundle clearance

Space mm ~ 200 ~ 200 ~ 200

4.13.00 Shell

a. Outside diameter mm 1764 1826 1760

b. Wall thickness mm 32 63 80

c. Shell skirt outside diameter mm 1764 1826 1780

d. Shell skirt thickness mm 32 63 90

e. Shell skirt length mm ~ 1600 ~ 1950 ~ 1600

f. Overall length mm ~ 12028 ~ 13555 ~ 10972

g. Withdrawal length

(From the end of Heater) mm ~ 8500 ~ 9800 ~ 7500

h. Type of dished end for shell

Cover (Hemispherical /Ellipsoidal or any other)

Ellipsoidal

i. Design pressure Kgf / cm2(g) 30 & F.V 74 & F.V 105 & F.V

j. Length of desuperheating zone mm 1500 2663 2015

k. Length of drain cooling zone mm 4396 4800 2193

l. Design temperature

i. Skirt deg. C 347 393 445

ii. Shell deg. C 235 290 315

m. Design vacuum mm Hg FULL VACUUM FULL VACUUM FULL VACUUM

n. Hydraulic test pressure Kgf/cm2(g) As per ASME Sec VIII Div-I

o. Corrosion allowance provided mm 3.2 3.2 3.2

p. Type of shell supports Roller

q. Whether stainless steel liners

are provided in the flashed drain inlets or not ?

Desuperheater and Draincooler shrouds protect the tubes,

hence steel liners not provided.

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r. Whether stainless steel band is

provide at the cutting point Yes

4.14.00 Impingement plates

a. Number 2 2 1

b. Thickness mm 8 8 8

4.15.00 Tube support plate, Tie rods etc.

a. No. of tube support plates in

i. Desuperheating zone 5 8 6

ii. Drain cooling zone 17 21 9

iii. Condensing zone 9 10 7

b. Thickness of tube support

plates mm 16 16 16

c. Spacing of support plates in

i. Desuperheating zone mm 297 332 335

ii. Drain cooling zone mm 226 201 174

iii. Condensing zone mm 970 849 885

d. Diameter of tie rods mm 20 20 20

e. No. of tie rods 14 14 14

f. Clearance between tube and

support plate hole in

i. Desuperheating zone mm 0.395 0.395 0.395

ii. Drain cooling zone mm 0.625 0.625 0.625

iii. Condensing zone mm 0.325 0.325 0.325

4.18.00 Material for Construction (indicate ASTM Specification)

a. Heater body

i. Skirt SA387 Gr.12 (SA516 GR.70 for HPH 7A/B)

ii. Shell SA516 Gr.70

iii. Head SA516 Gr.70

b. Water Box and Covers

i. Water box SA516 Gr.70

ii. Feed branches SA350 LF2

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iii. Water box cover SA350 LF2

c. Tube SA213 TP304 ‘N’

d. Tube sheet (including

overlayMaterial) SA350 LF2 CL1

e. Baffles and support plates IS2062

f. Impingement plates SA240 TP304

g. Antiflash baffles NA

h. Nozzles SA350 Lf2LL1304

i. Flanges SA105 for SRV Only

j. Tie rods and spacers CS & SS

k. Bolts SA193 B7

l. Nuts SA194 2H

m. Gaskets IJKT Gasket FOR Man Hole

4.19.00

Nozzle connection size (indicate no. size (mm) & type )

a. Feed water / condensate inlet 1 / Ø 615 Forg/ BW 1 / Ø 615 Forg/ BW 1 / Ø 615 Forg/ BW

b. Feed water / condensate outlet 1 / Ø 615 Forg/ BW 1 / Ø 615 Forg/ BW 1 / Ø 615 Forg/ BW

c. Steam inlet 1 / Ø 350 Forg / BW 1 / Ø 360 Forg / BW 1 / Ø 305 Forg / BW

d. Cascading drain inlet 1 / Ø 390 Forg /

BW 1 / Ø 315 Forg /

SW -

e. Cascading drain outlet 1 / Ø 430 Forg /

BW 1 / Ø 420 Forg /

BW 1 / Ø 320 Forg /

BW

f. Drain cooler bypass 1 / Ø 430 Forg /

BW 1 / Ø 420 Forg /

BW 1 / Ø 320 Forg /

BW

g. Shell drain 2 / Ø 33.4 x 4.55 2 / Ø 33.4 x 4.55 2 / Ø 33.4 x 4.55

h. Shell vent (Operating) 1 / Ø 33.4 x 4.55 1 / Ø 33.4 x 4.55 1 / Ø 33.4 x 4.55

i. Start up vent 1 / Ø 33.4 x 4.55 2 / Ø 33.4 x 4.55 1 / Ø 33.4 x 4.55

j. Water box drain 2 / Ø 33.4 x 9.09 2 / Ø 33.4 x 9.09 2 / Ø 33.4 x 9.09

k. Water box vent 2 / Ø 33.4 x 9.09 2 / Ø 33.4 x 9.09 2 / Ø 33.4 x 9.09

l. Water box relief valve 1 / ¾” ANSI SW 1 / ¾” ANSI SW 1 / ¾” ANSI SW

m. Shell relief valve 1 / 4” ANSI / RF 1 / 4” ANSI / RF 1 / 4” ANSI / RF

n. Stand pipes 4 / Ø 60.3 x 8.74 /

SW 4 / Ø 60.3 x 8.74 /

SW 4 / Ø 60.3 x 8.74 /

SW


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a. Nos. provided 1 1 1

b. Design code / Standard AS PER COLABORATORS STANDARD PRACTICE

c. Steam flow trough each orifice

at heater design. Kg / hr 255 394 296

d. Material orifice plate (indicate ASTM specification)

SA240 TP304

e. Diameter of orifice mm 4.9 6 4.9

f. Diameter of orifice plate mm 70 70 70

g. Thickness of orifice plate. mm 3.15 3.15 3.15

4.21.00 Start-up vent Orifice Not Applicable

a. Nos. provided

b. Design code / Standard

c. Material orifice plate (indicate ASTM specification)

d. Diameter of orifice mm

e. Diameter of orifice plate mm

f. Thickness of orifice plate. mm

g. Steam flow through each

Orifice. Kg / hr

4.22.00 Stand Pipe

a. Material ( Indicate ASTM Specification

SA106 Gr.B

b. Nominal diameter & thickness mm Ø 114.3 & 11.3 Ø 114.3 & 11.3 Ø 114.3 & 11.3

c. Overall length mm 2560 2560 2560

d. Nos. provided 4 4 4

e. Drain & isolation valve

provided Yes Yes Yes


a. Manufacturer & Model No. Later (As per approved list of vendors)

b. Type Transparent

c. Measurement range mm CC DISTANCE :1000 ; VISIBILITY : 800

d. Isolation, drain, vent & ball

check valve provided Yes Yes Yes

e. Number provided 1 per heater 1 per heater 1 per heater

4.24.00 Weights (Tons)

a. Empty 70 95 86

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b. Normal operating 79 105 95

c. Hydrostatic test weight flooded 87 116 102.3

d. Weight of tube bundle ~ 42 ~ 48.5 ~ 39.5

e. Weight of shell ~ 12.6 ~ 28.6 ~ 25.9

f. Weight of water box ~ 8.6 ~ 8.6 ~ 8.6

g. Total shipping weight 70 95 86

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CL. No. BIDDER’S NAME : BHEL – Hyderabad

4.00.00 DESUPERHEATER: Desuperheater to

HPH-7A/7B

4.01.00 Manufacturer BHEL, HYDERABAD

4.02.00 Model no. and Number off 1 Each

4.03.00 Type and arrangement U-Tube Horizontal

4.04.00 Design and construction standard ASME SEC VII DIV 1 2015 Edn. & HEI 9th Edn

4.05.00 No. of shell passes 1

4.06.00 No. of tube passes 2

4.07.00 No. of zones 3


a. Drain cooling zone m2 NA

b. Condensing zone m2 NA

c. Desuperheating zone m2 246.06

d. Ineffective area m2 NIL

e. Total area (provided) m2 333.4

f. Total extra surface provided m2 87.34


a) Heat (Kcal/Hr.) transferred x 106 Reference HBD No. – BD1033-ES EN TPEC PP-T0103 R9

i. Drain cooling zone NA

ii. Condensing zone NA

iii. Desuperheating zone 4.063

iv. Total Heat Transferred 4.063

b) EMTD (deg C)






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applied to each heat transfer zone

hr- m2 deg C / Kcal 0.0000631

e) Outer tube surface fouling

Factor Heat for

i. Drain cooling zone hr- m2 deg C / Kcal NA

ii. Condensing zone hr- m2 deg C / Kcal NA

iii. Desuperheating zone hr- m2 deg C / Kcal 0.0000615

f) Velocity through tubes m/sec

2.2

g. Drain level in heaters (Below the shell center line )

i. Normal mm NA

ii. Maximum mm NA

iii. Minimum mm NA


NA

4.10.00 i. Velocity through tubes at maximum flow.

m/s ~ 2.39

ii. Tube side pressure drop at maximum flow.

Kg / cm2 0.496


85

4.12.00 Tubes


or seamless) Welded U-Tubes to Specification SA213 TP304N

b) Total no. of U-tubes 758

c) No. of extra tubes provided 8

d) Effective length of U-tubes

(Total) mm 8913.28


mm 4600

f) Outside diameter mm 15.875

g) Wall thickness before

Bending (Avg.) mm 2.7

h) Minimum thickness at bend after

bending mm 2.36


tube % 0.05

j) Design pressure kg/cm2(g) 390 & F.V

APPROVED


Date: 03-Apr-2019


82


Date: 17-May-2020


85 / 136

k) Design temperature deg C

i) Desuperheating zone 355

ii) Other zones NA

l) Hydrostatic test pressure Kg/ cm2(g) 585

m) Type of tube-to-tubesheet

Joint Roller expanded and strength welded

n) Tube pitch Mm 21.43

o) Type of tube pattern Triangular

p) Shell / tube bundle clearance

Space mm ~ 200

4.13.00 Shell

a. Outside diameter mm 1190

b. Wall thickness mm 45

c. Shell skirt outside diameter mm 1190

d. Shell skirt thickness mm 45

e. Shell skirt length mm ~ 610

f. Overall length mm ~ 7640

g. Withdrawal length

(From the end of Heater) mm ~ 4200


Cover (Hemispherical /Ellipsoidal or any other)

Ellipsoidal

i. Design pressure Kgf / cm2(g) 30 & F.V

j. Length of desuperheating zone mm 8913.28

k. Length of drain cooling zone mm NA

l. Design temperature

i. Skirt deg. C 350

ii. Shell deg. C 512

m. Design vacuum mm Hg FULL VACUUM FULL VACUUM FULL VACUUM

n. Hydraulic test pressure Kgf/cm2(g) As per ASME Sec VIII Div-I

o. Corrosion allowance provided mm 3.2

p. Type of shell supports Roller



NA

APPROVED


Date: 03-Apr-2019


83


Date: 17-May-2020


86 / 136

r. Whether stainless steel band is

provide at the cutting point Yes


a. Number NA

b. Thickness mm NA



i. Desuperheating zone 8

ii. Drain cooling zone NA

iii. Condensing zone NA


plates mm 16


i. Desuperheating zone mm 540

ii. Drain cooling zone mm NA

iii. Condensing zone mm NA

d. Diameter of tie rods mm 20

e. No. of tie rods 13

f. Clearance between tube and


i. Desuperheating zone mm 0.395

ii. Drain cooling zone mm NA



a. Heater body

i. Skirt SA387 Gr.12




i. Water box SA516 Gr.70

ii. Feed branches SA350 LF2

APPROVED


Date: 03-Apr-2019


84


Date: 17-May-2020


87 / 136

iii. Water box cover MANMWAY COVER – SA 516 GR.70

c. Tube SA213 TP304 ‘N’

d. Tube sheet (including

overlayMaterial) SA350 LF2 CL1

e. Baffles and support plates SA387 Gr.12

f. Impingement plates SA240 TP304

g. Antiflash baffles NA

h. Nozzles SA182F11CL2

i. Flanges SA182F11CL2

j. Tie rods and spacers CS & SS

k. Bolts SA193 B7

l. Nuts SA194 2H

m. Gaskets IJKT Gasket FOR Man Hole

4.19.00

Nozzle connection size (indicate no. size (mm) & type )

a. Feed water / condensate inlet 1 / Ø 450 Forg/ BW

b. Feed water / condensate outlet 1 / Ø 450 Forg/ BW

c. Steam inlet 1 / Ø 410 Forg / BW

d. Cascading drain inlet NA

e. Cascading drain outlet 1 / Ø 350 Forg /

BW

f. Drain cooler bypass NA

g. Shell drain 2 / Ø 33.4 x 4.55

h. Shell vent (Operating) 1 / Ø 33.4 x 4.55

i. Start up vent 1 / Ø 33.4 x 4.55

j. Water box drain 2 / Ø 33.4 x 9.09

k. Water box vent 2 / Ø 33.4 x 9.09

l. Water box relief valve 1 / ¾” ANSI SW

m. Shell relief valve 1 / 4” ANSI / RF

n. Stand pipes 4 / Ø 60.3 x 8.74 /

SW

4.20.00 Operating Vent Orifice Not Applicable

APPROVED


Date: 03-Apr-2019


85


Date: 17-May-2020


88 / 136

a. Nos. provided



at heater design. Kg / hr


e. Diameter of orifice mm


g. Thickness of orifice plate. mm


a. Nos. provided


c. Material orifice plate (indicate ASTM specification)

d. Diameter of orifice mm

e. Diameter of orifice plate mm

f. Thickness of orifice plate. mm

g. Steam flow through each

Orifice. Kg / hr

4.22.00 Stand Pipe


SA106 Gr.B

b. Nominal diameter & thickness mm Ø 88.9 & 7.62

c. Overall length mm 1860

d. Nos. provided 4

e. Drain & isolation valve

provided Yes


a. Manufacturer & Model No. Later (As per approved list of vendors)

b. Type Transparent

c. Measurement range mm CC DISTANCE :1000 ; VISIBILITY : 800


check valve provided Yes

e. Number provided 1 per heater


a. Empty 33

APPROVED


Date: 03-Apr-2019


86


Date: 17-May-2020


89 / 136

b. Normal operating 36

c. Hydrostatic test weight flooded 40

d. Weight of tube bundle ~ 14

e. Weight of shell ~7.5

f. Weight of water box ~ 6.48

g. Total shipping weight 31

APPROVED


Date: 03-Apr-2019



87


Date: 17-May-2020


90 / 136

APPROVED


Date: 25-Feb-2019


88


Date: 17-May-2020


91 / 136

2.00.00 LP HEATERS LP Heater # 3 LP Heater # 4 LP Heater # 5


2.2.00 Model no. and Number of per set 1 1 1

2.3.00 Type and arrangement U – Tube Horizontal

2.4.00 Design and construction standard ASME SEC VIII Div.1 2015 UPTO & INCL. ADD, NIL & HEI

9TH EDN.

2.5.00 No. of shell passes 1 1 1

2.6.00 No. of tube passes 2 2 2

2.7.00 No. of zones 1 2 2


a. Drain cooling zone m2 NA 141.6 70.15

b. Condensing zone m2 1177.98 1047.27 955.34

c. Desuperheating zone m2 NA NA NA

d. Ineffective area m2 - - -

e. Total area m2 1177.98 1188.87 1025.49

f. Total extra surface provided m2 100.83 96.85 80.33


TMCR/RATED PR./660MW/0% MU/CP/34 deg.C CW.

(BD1033-ES-EN-PTEC-PP-T0103)

a) Heat (Kcal/Hr.) transferred x 106

i. Drain cooling zone NA 2.70 1.06


iii. Desuperheating zone NA NA NA

iv. Total heat transferred 38.06 35.98 30.42

b) LMTD (deg C)



Iii. Desuperheating zone NA NA NA




APPROVED


Date: 25-Feb-2019


89


Date: 17-May-2020


92 / 136

2



applied to each heat transfer zone hr-m2 deg C / Kcal)

0.0000463200 0.0000463090 0.0000463090

e) Outer tube surface fouling Factor Heat (hr-m2 deg C / Kcal)


ii. Condensing zone NA NA NA


f) Velocity through tubes m/sec 1.68 1.94 2.02

g) Drain level in heaters From Center line of heaters

i. Normal mm -544 -544 -544

ii. Maximum mm -140 -140 -140

iii. Minimum mm -610 -600 -600


mm 393 393 393


85 85 85

2.11.00 Tubes


or seamless) Welded (SA688 TP304)

b) Total no. of U-tubes 917 917 917

c) No. of extra tubes provided Nil Nil Nil

d) Effective length of U-tubes mm - - -


mm 10600 10700 9200

f) Outside diameter mm 19.05 19.05 19.05

g) Wall thickness before bending

mm 1 1 1

h) Minimum thickness at bend

after bending mm(BWG) 0.889 (20) 0.889 (20) 0.889 (20)


tube % 0.05 0.05 0.05

j) Design pressure kg/cm2(g) 50 & F.V 50 & F.V 50 & F.V

k) Design temperature (deg C)

i) Desuperheating zone deg C NA NA NA

APPROVED


Date: 25-Feb-2019


90


Date: 17-May-2020


93 / 136

3

ii) Other zones deg C 153 153 173

l) Hydrostatic test pressure kg/cm2(g) 75

m) Type of tube-to-tubesheet joint

Tubes will be rolled into tube sheet with Grooves

n) Tube pitch Mm 23.81 23.81 23.81

o) Groove dimensions 2- Ø20.81 x 3 2- Ø20.81 x 3 2- Ø20.81 x 3

p) Type of tube pattern Triangular Triangular Triangular

q) Shell / tube bundle clearance Space ( clearanace between outside diameter of tube bundle and inside diameter of shell)

mm 217 217 167

r) Tube withdrawal space required (for LP Heater – 1 only

NA NA NA

2.12.00 Shell

a. Outside diameter mm 1532 1532 1432

b. Wall thickness mm 16 16 16

c. Shell skirt outside diameter mm

NA d. Shell skirt length mm

e. Shell skirt thickness mm

f. Overall length mm 13083 13188 11551

g. Withdrawal length (From end of heater)

mm 10100 10300 10000


Cover hemispherical/ torispherical/ ellipsoidal

Tori Spherical

i. Design pressure Kgf / cm2(g) 3.5 & F.V 3.5 & F.V 6.5 & F.V

j. Length of desuperheating zone mm NA NA NA

k. Design temperature

i. Skirt deg. C NA

ii. Shell deg. C 162 240 301

l. Hydrostatic test pressure Kgf /

cm2(g) 5.25 9.75

m. Design vacuum mm Hg Full Vacuum Full Vacuum Full Vacuum

n. Corrosion allowance provided mm 3.2 3.2 3.2

APPROVED


Date: 25-Feb-2019


91


Date: 17-May-2020


94 / 136

4

o. Type of shell supports for LP Heater in condenser neck. Also indicate the shell length inside the condenser neck.

Mm NA NA NA

p. Dimension of the anti flash

baffle for LP heater in condenser neck & drain

NA NA NA



Yes Yes NA

r. Whether stainless steel liners

are provided at the cutting ? Yes Yes Yes

s. What type of provision has been provided for compensating differential expansion between shell and tube for drain cooler

NA NA NA


a. Number 2 2 1

b. Thickness Mm 8 8 8



i. Desuperheating zone NA NA NA

ii. Drain cooling zone NA 10 5

iii. Condensing zone 11 9 9


plates mm 16 16 16


i. Desuperheating zone mm NA NA NA

ii. Drain cooling zone mm NA 214 204

iii. Condensing zone mm 942 952 897

d. No. of tie rods 10 10 10

e. Diameter of the rods mm 20 20 20

f. Number of spacers 110 145 118

g. Clearance between tube and


i. Desuperheating zone mm NA NA NA

ii. Drain cooling zone mm 0.7 0.7 0.25

APPROVED


Date: 25-Feb-2019


92


Date: 17-May-2020


95 / 136

5

iii. Condensing zone mm 0.25 0.25 0.25


a. Heater body

i. Skirt NA

ii. Shell SA 516 Gr.70



i. Skirt NA



c. Water Box and Covers

i Water box pass partition

Plate SA516 Gr.70

ii Flow diffusers,

straighteners SA516 Gr.70

d. Tubes SA688 TP304

e. Tube sheet (including overlay

material) SA516 Gr.70 (No. Overlay)

f. Baffles and support plates IS 2062 Gr.B

g. Impingement plates SA240 Gr.304

h. Antiflash baffles Not Required.

i. Nozzles SA106 Gr.B / SA350 LF2 CL1

j. Flanges SA105 for SRV Only

k. Tie rods and spacers IS1570 & SA249 TP304

l. Bolts SA193 B7

m. Nuts SA194 2H

n. Gaskets CAF 9 for SRV & 4” SIZE

2.18.00 Nozzle connection size (indicate no./ size (mm) /& type )

a. Feed water / condensate inlet 1 / Ø 600mm /

BW 1 / Ø 600mm /

BW 1 / Ø 600mm /

BW

b. Feed water / condensate outlet 1 / Ø 600mm /

BW 1 / Ø 600mm /

BW 1 / Ø 600mm /

BW

APPROVED


Date: 25-Feb-2019


93


Date: 17-May-2020


96 / 136

6

c. Steam /Drain inlet 1 / Ø 832mm /

BW 1 / Ø 711mm /

BW 1 / Ø 660mm /

BW

d. Cascading drain inlet 1 / Ø 273mm /

BW 1 / Ø 273.1mm /

BW NA

e. Cascading drain outlet 1 / Ø 273mm /

BW 1 / Ø 219.1mm /

BW 1 / Ø 219.1mm /

BW

f. Drain cooler bypass (not

applicable for LP heater-1)

f. Shell vent ( operating ) 1/Ø114.3mm/

BW 1/Ø114.3mm/

BW 1/Ø114.3mm/

BW

g. Shell drain 2/1”ANSI/SW 2/1”ANSI/SW 2/1”ANSI/SW

h. Start up vent 1/1”ANSI/SW 1/1”ANSI/SW 1/1”ANSI/SW

i. Water box relief valve 1/¾”ANSI/SW 1/¾”ANSI/SW 1/¾”ANSI/SW

j. Shell relief valve 1/4”ANSI/RF 1/4”ANSI/RF 1/4”ANSI/RF

k. Stand pipes 2” ANSI / SW 2” ANSI / SW 2” ANSI / SW


a. Nos. provided 1 1 1

b. Design code / Standard As per Standard BHEL practice


at heater design condition Kg / hr Negligible


SS 304


a. Nos. provided


c. Steam flow at start-up

d. Material of orifice plate

(indicate ASTM specification)

e. Diameter of orifice



2.21.00 Stand Pipe

APPROVED


Date: 25-Feb-2019


94


Date: 17-May-2020


97 / 136

7


CS (SA106 Gr.B)

b. Nominal diameter & thickness Ø88.9 & 11.13 Ø88.9 & 11.13 Ø88.9 & 11.13

c. Overall length mm 2413 2413 2413

d. No.s provided 2 2 2

e. Drain & isolation valve provided Yes Yes Yes


a. Manufacturer & Model No. As per approved list of vendors

b. Type Transparent

c. Measurement range mm C-C DIST : 800, VISIBILITY : 590


check valve provided Yes Yes Yes

e. Number provided 1 1 1


a. Empty 26.5 27.5 24.5

b. Normal operating 33.5 36.5 31.5

c. Hydrostatic test weight flooded 45.5 48.5 40

d. Weight of tube bundle 18.45 15.85 16.6

e. Weight of shell 7.34 6.13 6.3

f. Weight of water box 2.93 2.93 2.93

g. Total shipping weight 26.5 27.5 24.5

h. Weight of heaviest single

piece during. (Tons)

i Erection (Heater Assly.) 26.5 27.5 24.5

2.24.00 Shipping Dimensions (mm) (indicate the following for heaviest as well as largest piece

a. Length mm 13083 13188 11551

b. Breadth mm 2000 2000 190

c. Height mm 2300 2300 2100

APPROVED


Date: 25-Feb-2019



95


Date: 17-May-2020


98 / 136

APPROVED


Date: 31-Dec-2018


96


Date: 17-May-2020


99 / 136

2.00.00 DRAIN COOLER Drain Cooler


2.2.00 Model no. and Number of per set 1

2.3.00 Type and arrangement Straight tubes , Horizontal

2.4.00 Design and construction standard ASME SEC VIII Div.1 2015 UPTO & INCL. ADD, NIL & HEI

9TH EDN.

2.5.00 No. of shell passes 1

2.6.00 No. of tube passes 1

2.7.00 No. of zones 1


a. Drain cooling zone m2 151.39

b. Condensing zone m2 NA

c. Desuperheating zone m2 NA

d. Ineffective area m2 NA

e. Total area m2 159.19

f. Total extra surface provided m2 93.73


TMCR/RATED PR./660MW/0% MU/CP/34 deg.C CW.

(BD1033-ES-EN-PTEC-PP-T0103)

a) Heat (Kcal/Hr.) transferred x 106

i. Drain cooling zone 0.631


iii. Desuperheating zone NA

iv. Total heat transferred 0.631

b) LMTD (deg C)



Iii. Desuperheating zone NA




APPROVED


Date: 31-Dec-2018


97


Date: 17-May-2020


100 / 136

2



applied to each heat transfer zone hr-m2 deg C / Kcal)

0.000045180

e) Outer tube surface fouling Factor Heat (hr-m2 deg C / Kcal)




f) Velocity through tubes m/sec 2.11

g) Drain level in heaters From Center line of heaters

i. Normal mm NA

ii. Maximum mm NA

iii. Minimum mm NA


mm NA


85

2.11.00 Tubes


or seamless) Welded (SA688 TP304)

b) Total no. of straight tubes 671

c) No. of extra tubes provided 6

d) Effective length of tubes mm 4000


mm NA

f) Outside diameter mm 19.05

g) Wall thickness before bending

mm NA

h) Minimum thickness at bend

after bending mm(BWG

NA


tube % 0.05

j) Design pressure kg/cm

2(g) 50 & F.V

k) Design temperature (deg C)

i) Desuperheating zone deg C NA

APPROVED


Date: 31-Dec-2018


98


Date: 17-May-2020


101 / 136

3

ii) Other zones deg C 152

l) Hydrostatic test pressure kg/cm

2(g) 75

m) Type of tube-to-tubesheet joint

Tubes will be rolled into tube sheet with Grooves

n) Tube pitch Mm 23.81

o) Groove dimensions 3mm, 2 nos.

p) Type of tube pattern Triangular

q) Shell / tube bundle clearance Space ( clearanace between outside diameter of tube bundle and inside diameter of shell)

mm 26

r) Tube withdrawal space required (for LP Heater – 1 only

NA

2.12.00 Shell

a. Outside diameter mm 736

b. Wall thickness mm 12

c. Shell skirt outside diameter mm

NA d. Shell skirt length mm

e. Shell skirt thickness mm

f. Overall length mm 6310

g. Withdrawal length (From end of heater)

mm 4000


Cover hemispherical/ torispherical/ ellipsoidal

Flat End

cover

i. Design pressure Kgf /

cm2(g) 3.5 & F.V

j. Length of desuperheating zone mm NA

k. Design temperature

i. Skirt deg.

C NA

ii. Shell deg. C

152

l. Hydrostatic test pressure Kgf / cm2(g

5.25

m. Design vacuum mm Hg

Full Vacuum

n. Corrosion allowance provided mm 3.2

APPROVED


Date: 31-Dec-2018


99


Date: 17-May-2020


102 / 136

4

o. Type of shell supports for LP Heater in condenser neck. Also indicate the shell length inside the condenser neck.

Mm NA

p. Dimension of the anti flash

baffle for LP heater in condenser neck & drain

NA



Yes

r. Whether stainless steel liners

are provided at the cutting ? Yes

s. What type of provision has been provided for compensating differential expansion between shell and tube for drain cooler

NA


a. Number 1

b. Thickness Mm 8



i. Desuperheating zone NA

ii. Drain cooling zone 9

iii. Condensing zone NA


plates mm 16


i. Desuperheating zone mm NA

ii. Drain cooling zone mm 431


d. No. of tie rods 6

e. Diameter of the rods mm 20

f. Number of spacers 48

g. Clearance between tube and


i. Desuperheating zone mm NA

ii. Drain cooling zone mm 0.7

APPROVED


Date: 31-Dec-2018


100


Date: 17-May-2020


103 / 136

5



a. Heater body

i. Skirt NA

ii. Shell SA 516 Gr.70



i. Skirt NA



c. Water Box and Covers

i Water box pass partition

Plate NA

ii Flow diffusers,

straighteners NA

d. Tubes SA688 TP304

e. Tube sheet (including overlay

material) SA516 Gr.70 (No. Overlay)

f. Baffles and support plates IS 2062 Gr.B

g. Impingement plates NA

h. Antiflash baffles Not Required.

i. Nozzles SA106 Gr.B / SA350 LF2 CL1

j. Flanges SA105 for SRV Only

k. Tie rods and spacers IS1570 & SA249 TP304

l. Bolts SA193 B7

m. Nuts SA194 2H

n. Gaskets CAF 9 for SRV & 4” SIZE

2.18.00 Nozzle connection size (indicate no./ size (mm) /& type )

a. Feed water / condensate inlet 1 / Ø 450mm /

BW

b. Feed water / condensate outlet 1 / Ø 450mm /

BW

APPROVED


Date: 31-Dec-2018


101


Date: 17-May-2020


104 / 136

6

c. Steam /Drain inlet 1 / Ø 273.1mm /

BW

d. Cascading drain inlet NA

e. Cascading drain outlet 1 / Ø 273mm /

BW

f. Drain cooler bypass (not

applicable for LP heater-1) NA

f. Shell vent ( operating ) NA

g. Shell drain 1/1”ANSI/SW

h. Start up vent 1/1”ANSI/SW

i. Water box relief valve 1/¾”ANSI/SW

j. Shell relief valve NA

k. Stand pipes NA


a. Nos. provided NA 1 1

b. Design code / Standard NA


at heater design condition Kg / hr NA


NA


a. Nos. provided


c. Steam flow at start-up

d. Material of orifice plate

(indicate ASTM specification)

e. Diameter of orifice



2.21.00 Stand Pipe NA


NA

APPROVED


Date: 31-Dec-2018


102


Date: 17-May-2020


105 / 136

7

b. Nominal diameter & thickness NA

c. Overall length mm NA

d. No.s provided NA

e. Drain & isolation valve provided NA


a. Manufacturer & Model No. NA

b. Type NA

c. Measurement range mm NA


check valve provided NA

e. Number provided NA


a. Empty 6

b. Normal operating 9

c. Hydrostatic test weight flooded 9

d. Weight of tube bundle 1.76

e. Weight of shell 1.1

f. Weight of water box .947

g. Total shipping weight 6

h. Weight of heaviest single

piece during. (Tons) 6

i Erection (Assly.) 6

2.24.00 Shipping Dimensions (mm) (indicate the following for heaviest as well as largest piece

a. Length mm 6310

b. Breadth mm 750

c. Height mm 1320

APPROVED


Date: 31-Dec-2018



103


Date: 17-May-2020


106 / 136


Sep Tue 18 10:21 2018

APPROVED


Date: 05-Oct-2018


99104


Date: 17-May-2020


107 / 136


Sep Tue 18 10:22 2018

APPROVED


Date: 05-Oct-2018


100105


Date: 17-May-2020


108 / 136


Sep Tue 18 10:22 2018

APPROVED


Date: 05-Oct-2018


101106


Date: 17-May-2020


109 / 136


Sep Tue 18 10:22 2018

APPROVED


Date: 05-Oct-2018


102107


Date: 17-May-2020


110 / 136


Sep Tue 18 10:22 2018

APPROVED


Date: 05-Oct-2018


103108


Date: 17-May-2020


111 / 136


Sep Tue 18 10:23 2018

APPROVED


Date: 05-Oct-2018


104109


Date: 17-May-2020


112 / 136


Sep Sat 22 09:43 2018

APPROVED


Date: 05-Oct-2018


105110


Date: 17-May-2020


113 / 136


Sep Sat 22 09:43 2018

APPROVED


Date: 05-Oct-2018


106111


Date: 17-May-2020


114 / 136

APPROVED


Date: 05-Oct-2018


107112


Date: 17-May-2020


115 / 136

APPROVED


Date: 05-Oct-2018


108113


Date: 17-May-2020


116 / 136

APPROVED


Date: 05-Oct-2018


109114


Date: 17-May-2020


117 / 136

APPROVED


Date: 23-Oct-2018


110115


Date: 17-May-2020


118 / 136


Jun Sat 2 10:17 2018

FIO


Date: 15-Oct-2018


111116


Date: 17-May-2020


119 / 136


Jun Fri 1 09:44 2018

FIO


Date: 23-Oct-2018



112117


Date: 17-May-2020


120 / 136

FIO


Date: 20-Jun-2018



113118


Date: 17-May-2020


121 / 136

FIO


Date: 20-Jun-2018



114119


Date: 17-May-2020


122 / 136


Sep Sat 22 14:16 2018

FIO


Date: 16-Oct-2018


115120


Date: 17-May-2020


123 / 136

TWIN OIL COOLERS

121


Date: 17-May-2020


124 / 136

Description Operation and Maintenance

TWIN OIL COOLERS


TWIN OIL COOLER

INTRODUCTION

A large amount of heat is generated at the bearings of rotating machinery. To remove this excess heat lubricating oil is circulated through the bearings.

In the closed cycle operation of the oil circuit, one or more coolers are placed on the discharge side of the oil pump. The oil coolers which received oil that has absorbed the waste heat, cools it to the temperature that is required at the bearings.

Two coolers have been provided with 100% capacity each. As such one cooler is in service and one is always standby. The coolers are mounted vertically for easy removal of the tubenest. Dirt in the water if any falls into the sump at the bottom.

CONSTRUCTION

The oil cooler is a shell and tubenest arrangement. The tubenest consist of two tube sheets into which the tubes are roller expanded. One tube sheet is fixed while the other sides on an annular seal to allow for thermal expansin. The tubesests has a numbf of baffles arranged in disc and doughtnut type speed at intervals such that oil which enters the coolers at the bottom of the shell is made to flow upwards in zig-zag manner.

The cooling water flows through the tubes in a two pass / four pass arrangements by the provision of baffles in the water boxes. The cooling water

flows down wards ensuring complete flooding at all times. The tubenest is housed in a fabricated cylindrical shell.

For inspection of the tubenest it is enough to remove the rear end water chamber as well as the inspection cover on inlet/outlet water chamber. For cleaning of the tubes as well as for attending to repairs, the tubenest along with the water chamber can be withdrawn form the shell.

Oil can be drained from the cooler through a flanged connection at the bottom of the shell. Air accumulated in the oil space can be expelled through a vent. Likewise on the water side of the cooler also an air vent is provided at the top and a drain cock at the bottom. The oil inlet and outlet nozzles are provided with screwed thermometer connections. Thermometer pockets are also provided in the water boxers for measurement of temperature of the cooling water.

122


Date: 17-May-2020


125 / 136


TWIN OIL COOLERS


OPERATION

Open the water inlet valve and open the air vent cock on the water box cover. Close the air vent when there is a steady steam of water through the vent. Open oil inlet and outlet of the selected cooler and vent the oil side completely as before. When the temperature of the oil at the outlet from the cooler has reached the required value, regulate the flow of cooling water through the cooler by adjusting the outlet valve.

The bring the standby coolers into operation processed as follows:

On water side operate the standby coolers as before. Now open the insulation valves to bring the oil side of the standby coolers into operation and shut down the oil side of the running coolers gradually. For shutting down a running cooler close oil outlet, cooling water outlet, oil inlet and finally cooling water inlet in the order.

A) Oil side Range

i) Pressure gauge on the inlet side

0 to 10 Kg/cm2

ii) Pressure gauge on the outlet side

0 to 10 Kg/cm2

iv) Thermometer on the inlet side

0 to 150 Dec.C

v) Thermometer on the outlet side

0 to 150 Dec.C

B) Water side

i) Pressure gauge on the inlet side

0 to 10 Kg/cm2

ii) Thermometer on the inlet side

0 to 150 Dec.C

iii) Thermometer on the outlet side

0 to 150 Dec.C

TROUBLE SHOOTING

Oil coolers if properly maintained give trouble-free service over long periods. The table below gives some of the problems encountered during operation and remedies suggested.

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TWIN OIL COOLERS


Nature of problem Probable cause

1. Inadequate cooling as oil Points 1,2,3, 7 & 8

2. Pressure drop on oil side high Point 2

3. Pressure drop on water side high Point 1

4. Loss of contamination of oil in oil coolers

Point 4, 5 & 6

5. No pressure drop on oil side Point 3

6. Temperature rise on water side Point 7

Probable Cause Rectification

1. Tube inside surface not clean a) Remove all the soft deposits by brush cleaning.

b) Remove all hard deposits by chemical cleaning

c) Check quality of cooling water periodically.

2. Tube outside surfaces not clean and clogging on shell side

a) Remove sludge, scale of film on the outside of the tubes as well as the inside of the shell.

b) check whether oil filters are in position.

3. Oil being by passed a) Check whether the annular seal is correctly positioned.

4. Tube puncture a) Plug or replace the failed tube

5. Oil pressure less than of water a) Check whether oil pipelines are clogged.

b) Check the discharge pressure of oil pumps.

6. Leakage through expansion joints a) Re-expand or plug all leaking joints

b) Check whether oil cooler is subjected to vibration.

c) Check whether cooling water flow is OK

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TWIN OIL COOLERS


Probable Cause Rectification

Pre-commissioning check list

1. Hydraulic test a) The equipment is normally pressure tested at the manufacturing work.

b) Check water the same has been conducted.

c) If not, pressure test the cooling water side and shell side separately and observe for leaks.

d) Test parameters :

Pressure : As given in the drawings

Quality of water : Clean & fresh.

Test duration : Minimum 30 minutes

Test results : Satisfactory or not

e) Precaution : Test pressure should not exceed that given in the drawings.

f) All the water is to be drained off and the equipment kept by.

2. Tapping points a) Check the instrument tapping points on the equipment with respect to scheme.

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TWIN OIL COOLERS


CHECK LIST BEFORE START UP

1. Check whether the oil cooler tubes are cleaned with fresh demineralize water.

2. Check whether all the instruments i.e., pressure gauges and thermometers on oil and water side are calibrated and mounted.

3. Check whether all the connection to the oil cooler are made properly.

4. Check whether all the maintenance works such as painting are completed.

DO’S AND DON’TS DURING OPERATION

Do’s

1. Admit first cooling water into oil cooler tubes by slowly opening the inlet valve.

2. After oil cooler are completely charged with water admit oil.

3. Maintain constant check on all the instrumentation provided on the oil cooler.

4. If two or more coolers are in operation in parallel ensure that the pressure drop on oil side in all the coolers is nearly the same.

5. For longer life of the tube, ensure that the cooling water flow through the cooler as minimum.

Don’ts

1. Do not operate the oil cooler beyond the rated pressure and temperature of oil and water.

2. Do not admit oil before the cooler is charged with cooling water.

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TWIN OIL COOLERS


CHECK LIST DURING SHUT DOWN

1. Check whether the oil and water and drained completely and equipment kept dry.

DO’S AND DON’TS DURING SHUT DOWN

Do’s

1. If the oil is not getting cooled to the required value open the oil cooler, check the condition of the tubes.

2. Clean the tubes if they are dirty.

Don’ts

1. Do not force open any component when the cooler is taken up for maintenance/repairs.

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TWIN OIL COOLERS


MAINTENANCE

The efficiency of the cooler depends of the cooling surfaces. Dirty water if allowed to flow through the cooler not only impairs to flow through the cooler not only impairs the cleanliness of the tube but also restricts the cooling water handling capacity of the cooler by forming sludge in the tube surfaces and reducing its areas. Similarly dirty or contaminated oil if allowed to flow through the cooler will form sludge or scales on the outside of the tubes and reduce heat transfer.

It is therefore essential that the cooling water as well as oil should, at all times, be as per standards. If not the cleanliness of the tubes must be ensured by cleaning the tubes must be ensured by cleaning the tubenest at frequent intervals.

CLEANING OF THE INSIDE SURFACES OF TUBES.

This can be done with the cooler in position with the top water box removed for accessibility and the bottom water for collection of dirt. Use soft brittle or brass wire brushes and employ easy long strokes. If the deposits are not removed by this method chemical cleaning may be resorted to under the supervision of a qualified chemist.

The outside surface of the tubes can also be cleaned in a similar manner except the chemical cleaning will be more elaborate.

However, during general maintenance work, the following points may be adhered to

a) Clean the tubes thoroughly with fresh water.

b) Plug all tubes suspected to be leaking.

c) Clean the water boxes and ensure that they are free from mud, dirt, sedimentation, rust, scales etc.

d) Check the condition of gaskets and replace, If necessary.

e) Recalibrate all instruments and replace, if necessary.

f) Check the condition of painting and renew if necessary.

g) Check the condition of valves and lap the weats if necessary.

h) When not in use, the oil: cooler should be kept completely dry both on oil and water side.

i) To prevent problems due to corrosion ensure that water and oil sides are completely free from air. Also ensure that the cooling water pump glands are not a source of leakage.

If the performance of the oil cooler is upon the requirement, check and ensure the following :

a) Cleanliness of the tubes both inside and outside.

b) Accuracy of the measuring instruments.

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TWIN OIL COOLERS


c) Perfect sealing of drain and vent cock fittings.

d) Proper regulation of cooling water outlet valve.

e) The oil side pressure is more than that on the water side.

f) Water has not frozen in cooling water pipes in extreme cold whether.

PRESERVATION

a) The oil cooler is painted on the out side with two coats of redoxide.

b) On the inside it is thoroughly dried and all the connection are sealed with plugs or blank flanges.

c) The oil cooler on receipt at site must be stored on an elevated platform under a roof.

d) If their pressure of moisture in the internals of the oil cooler is suspected, blow hot air through and introduce packets of silica-gel and renew the blank flanges and plugs.

e) During commissioning, the tube side as well as the shell side are rinsed thoroughly with dematerialized water to remove scales, rust, foreign matter etc.

g) During temporary shut down of the machine, the oil cooler will run full both on oil and water side.

h) During prolonged shut down of the machine the oil cooler completely both on oil & water side and kept perfectly dry.

PIPELINE FLUSHING

While flushing the oil lines, the oil coolers should be isolated on oil side till pipe lines are fully clean to avoid pipe line sludge etc. getting into the coolers. If required a temporary connection should be introduced for by passing the coolers on oil side. Coolers should be brought in the flushing circuit only after ensuring the cleanliness of the connecting oil pipelines. The above is required to avoid the difficult task of cleaning of the shell side of the tube bundle, if the oil line sludge gets lodged in the cooler.

CAUTION : Removal of sludge from all pockets of oil pipe line may be ensured prior to inclusion of oil coolers in the flushing circuit.

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PROJECT TITLE : 2X660MW MAITREE STPP

CUSTOMER : BANGLADESH-INDIA FRIENDSHIP POWER COMPANY (PVT.)

CONSULTANT : FICHTNER

EQUIPMENT : BFPDT OIL COOLER (CALCULATIONS)

Sl. No MAITREE (Customer) Comment (23.02.2018) BHEL Reply on 26.03.2018 MAITREE (Customer) Comment (09.06.2018) BHEL ReplyMAITREE (Customer) Comment

(16.10.2018)BHEL Reply

1

Heat exchanger calculation shall be as per TEMA.

Manual calculation as per Section-7 of TEMA to be

submitted and HTRI software output shall be

validated.

For shell and tube heat exchanger thermal sizing is carried out

using HTRI software. Output sheet obtained from HTRI is

enclosed for information.

Comment repeated

BHEL to furnish sample calculation as per TEMA and

the same shall be validated with HTRI software

output.

It is again clarified that calculations are

done using HTRI software. Manual

calculations are not being done. Hence,

the same can not be furnished.

No Comment Point Closed

2

What is the inside and out side film co-efficient

considered for calculation and basis of same to be

described.

Available in the HTRI data summary sheet (marked in DATA

sheet).Please clarify the basis.

Film heat transfer coefficient given is

optimized based on tube material,

thickness, baffle cut and baffle spacing by

HTRI software.

The same can not be demonstrated by

manual calculations as HTRI adopts

optimized stream analysis methods for

establishing film coefficeints which are

accepted world wide.

No Comment Point Closed

3What is the thermal conductivity considered as

input.

Shell Side: 0.1280 kcal/hr-m-C

Tube Side: 0.5385 kcal/hr-m-CNo Comment. Point Closed.

-- --

4 10% plugging condition to be considered Noted & confirmed No Comment. Point Closed. -- --

5 Shell Side Fouling factor 0.0002 to check Confirmed. No Comment. Point Closed.-- --

6

Tube Wall Thickness: Tube shalll be designed for 1.2

times of shut-off head of DMCW pump and hydro

test shall be 1.5times of design pressure. Check tube

wall thickness considering same

We Confirm that the deisgn pressure considered is more than

1.2 times of the shut-off head of DMCW pump.

Hydro test pressure shall be 1.3 times of design pressure as per

the ASME section VIII Div.1

BHEL to refer FTS clause B0.6.17.6, as per which the

design pressure shall be 1.2 times shut-off head and

hydro test pressure shall be 1.5 times the design

pressure.

BHEL to comply spec. requirements.

We Confirm. No Comment Point Closed

7

Tube Pitch/Type: As provision of cleaning of cooler

tube is specified, tringular pattern is not permitted as

per Section-5 of TEMA and tube pitch shall be

1.25times of tube OD plus 6.4mm. Revise

Shell side cleaning is not required as the circulating fluid is oil.

So, triangular pattern and tube pitch which are provided in data

sheet are adequate.

No Comment. Point Closed.

-- --

8Fouling Factor Tube Side: As per RGP Section of

TEMA this shall be 0.0005.

0.0005 which is mentioned in TEMA is in Btu units which is

equalant to 0.0001 h.m2.K/Kcal. So, fouling factor provided is

higher than the TEMA required.


-- --

9

Tempreature Shell Side: As per B0.6.17.6, the heat

exchangers shall be designed for the maximum

temperature incurred plus 20 K. Revise

Shell side designed temperature considered is 100°C which is

higher than the operating temperature by 42 °C. No Comment. Point Closed.

-- --

10Flow Rate Shell Side: Furnish break-up of lube oil

requirement for BFPDT

A. Turbine FJB - 4.55 m3/hr @ 24.82 KW

B. Turbine RJB - 4.58 m3/hr @ 25.00 KW

C. Turbine Thrust bearing - 17.26 m3/hr @ 101.41 KW

D. Gear Box - 2.4 m3/Hr @ 15 KW

E. BFP - 13.0 m3/hr @ 166 KW


-- --

11BHEL to submit TEMA standard with the next

revision for approval of this document.Noted. Being addressed. No Comment Point Closed

12

Please check the oil flow rate, w.r.t.

document no. 350114, the flow rate is

45.19 m3, accodingly, please revise the

mass flow.

Oil Flow rate 46.49 m3/hr updated as per the latest

P&ID. Reference D. No: MAITREE-00-XAV-ME-

355003-HYD Rev.03

We understand that the referred document 350114

is only for TDBFP pump, whereas oil cooler refers

for total oil quantity as per Lube oil P&ID.

13

please correct mass flow w.r.t. volume flow

of 45.19 m3/hr

Oil Flow rate 46.49 m3/hr updated as per the latest

P&ID. Reference D. No: MAITREE-00-XAV-ME-

355003-HYD Rev.03

14

Basis of this pressure may be furnished

Please note that lube oil header operating

pressure is 11.5 ata and DMCW operating

pressure is 10 ata. BHEL to properly

consider inlet operating pressure.

Inlet Pressure of Lube oil is 10.6 Kg/Sq.cm

Inlet Pressure of DMCW is 4.6 Kg/sq.cm

15

Please furnish sample calculation, as this is

not matching with the inputs given in above

table.

Heat Duty (Q): 285732 Kcal/Hr

Oil Flow Rate(m): 39284 Kg/hr (46.49 m3/Hr)

Oil Density:845 Kg/m3

Oil Inlet Temp(T1): 62.18 °C

Oil Outlet Temp(T2): 47 °C

Average Specific Heat(Cp): 0.47915 Kcal/Kg.°C

Q=mCp(T1-T2)=285732 Kcal/Hr

16In GAD, the spacing indicated as 135mm,

please clarify.Noted. GAD updated inline with thermal data.

FIO


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HEAT EXCHANGERS ENGINEERING

BHARATH HEAVY ELECTRICALS LIMITED RAMACHANDRAPURAM HYDERABAD – 502 032

2X660 MW MAITREE BANGLADESH BFPDT TWIN OIL COOLER SIZING

DRG. NO: HY-DG-3-16505-34201 MAITREE-00-MAG-LU-360061-HYD

CAL.NO: HE-CLR-1342 REV 02

Rev 00

Prepared by

SPJ

29.12.17

Checked by

SSR

29.12.17

Approved by

KKK

29.12.17

THERMAL CALCULATIONS AS PER HTRI SHELL&TUBE HEAT EXCHANGER

Rev 01 20.09.18 Rev 02 28.11.18

HTRI OUTPUT SUMMARY

SHELL SIDE INFORMATION

NO. OF SHELLS IN SERIES/PARALLEL 1/ 1

TOTAL SURFACE AREA(GROSS) SQ.M 84

SHELLSIDE FLUID --- HOT (LUBE OIL)

TEMA SHELL TYPE --- AEW

SHELL OUT. DIA. MM 508

BAFFLE TYPE --- SEGMENTAL

BAFFLE CUT % 20

BAFFLE CENTRAL SPACING MM 150

NUMBER OF CROSSPASSES --- 24

FOULING FACTOR M2. Hr.0C/K. Cal 0.0002

TUBE SIDE INFORMATION

TUBE MATERIAL --- STAINLESS STEEL

TUBE TYPE --- PLAIN WELDED

NUMBER OF TUBE PASSES --- 4

NUMBER OF TUBES --- 436

TUBE LENGTH OVERALL MM 4000

TUBE OUTER DIA MM 15.875

TUBE WALL THK. MM 1.245

TUBE LAYOUT ANGLE --- 30

TUBE PITCH/ TYPE MM 19.05/ TRIANGLE

FOULING FACTOR M2. Hr.0C/K. Cal 0.0002

TEMPERATURE SHELL SIDE INLET/OUTLET 0 C 62.18/47

TUBE SIDE INLET/OUTLET 0 C 38/ 40.86 PERFORMANCE ANALYSIS

PERCENT OVERDESIGN % 36.88

TOTAL HEAT DUTY K.Cal/Hr 285732 H.T. COEFFICIENTS

OVERALL K.Cal / M2. Hr.0C 257.69

SHELLSIDE K.Cal / M2. Hr.0C 466.05

TUBESIDE K.Cal / M2. Hr.0C 7604.8

EFFECTIVE MTD 0 C 13.2

PRESSURE DROPS

SHELL TOTAL Kg/Cm2 0.6

ALLOWABLE Kg/Cm2 0.7

TUBE TOTAL Kg/Cm2 0.9

ALLOWABLE Kg/Cm2 1.0

FLOW RATE SHELL Kg/Hr 39284

TUBE Kg/Hr 100000 VELOCITY

SHELL M/Sec 0.4

TUBE M/Sec 1.82

01

02

02

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x

/ /

0.6

0.000200

39284

0.1274

Impingement Plate

508

10.600

13.500 /

1

OD

InletSingle-Seg. %Cut (Diam)

Tubesheet-Floating

Channel Cover

Rectangular plate

Tube No.

mm

Channel or Bonnet

Reprinted with Permission (v7.3)

Weight/Shell kg

Baffles-Cross

Baffles-Long

436

Tubesheet-Stationary

Type

mm

Thk(Avg)

Material

Connections

Out

In

Size &

Intermediate

mmOD

mm

Rating

No Passes per Shell

Design/Test Pressure

Design Temperature

Corrosion Allowance

Code Requirements

Rho-V2-Inlet Nozzle

Floating Head Cover

Bypass Seal Arrangement

Expansion Joint

TEMA Class C

NoneType

Expanded (No groove)

Bundle Exit kg/m-s2

150.00Spacing(c/c)

Seal Type None

20 mm

Bundle Entrancekg/m-s2

Tube-Tubesheet Jointpairs seal strips

Tube Side

Filled with Water Ref GAD kg kg

Remarks:

Bundle

Supports-Tube

2629.5

Gaskets-Shell Side

U-Bend

Type

Ref GAD

-

0.000

Tube SideShell Side

100.00

1 4

100.00

kgf/cm2G

C

mm

0

1

@

15.875

@

257.24

m2-hr-C/kcal

CONSTRUCTION OF ONE SHELL

Fouling Resistance (min)

MTD (Corrected)

Actual

Sketch (Bundle/Nozzle Orientation)

C

Pressure Drop, Allow/Calc

Heat Exchanged

0.700

Clean

kcal/hr285732

kcal/m2-hr-C

kgf/cm2

Transfer Rate, Service

m/s

Thermal Conductivity

Velocity

Latent Heat

Specific Heat

kgf/cm2AInlet Pressure

kcal/kg-C

kcal/hr-m-C

kcal/kg

Molecular Weight, Noncondensables

62.18

0.8296

Molecular Weight, Vapor

Steam

CTemperature (In/Out)

cP

Fluid Quantity, Total

Viscosity

Noncondensables

kg/hr

Plant Location RAMPAL, BANGLADESH

Service of Unit

Shell/Unit

Fluid Allocation

Job No.

Reference No.

Proposal No.

Date

84 Surf/Shell (Gross/Eff)

Series1mm Connected In

Item No.

Rev

m284

100000 100000

PERFORMANCE OF ONE UNIT

Tube Side

Customer

Address

HEAT EXCHANGER SPECIFICATION SHEET Page 1

MKH Units

BIFPCL, MAITREE BANGALDESH HY-DS-4-16505-34201

m2

Parallel

Liquid

Water

Specific Gravity

Vapor (In/Out)

HorizontalAEW

Fluid Name

1

100000

WATER

Size Type489 4000

Surf/Unit (Gross/Eff)

Shell Side

OIL

47.00

39284 39284

0.8524

38.00

0.4

0.9936 0.9925

4"

4"

0.000

@

@

4"

@

10.000

1

1

/

30304 Stainless steel (18 Cr, 8 Ni)

mm 19.050 mm Pitch

4"

Shell Cover

Tube pattern

mm

Shell

Plain

304 Stainless steel (18 Cr, 8 Ni) ID 489.00

0.000200

Tube Type

@

1.245 4000.Length

1

28-11-2018

40.86

01

0.4640 0.9985 0.9985

0.1297

0.9

4.600

1.82

9.3703 32.719 0.6783 0.6426

0.4943

0.5385 0.5417

Floating Head

13.2

1.000

kcal/m2-hr-C kcal/m2-hr-C

01

01

01 01

F:\Naresh\Official\HE&F\Design\2017-18\MAITREE BANGLADESH\18. Oil Cooler - Maitree Bangaldesh\Thermal Run\Maitree

Bangladesh-2x660mw (Foc cust submission).htri

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Date: 19-Dec-2018



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Nov Wed 28 08:59 2018

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