Power Plant Handbook

MIL Controls Limited A KSB Company

MAJOR SYSTEMS VALVE SELECTION MATERIAL SELECTION INSTALLATION & MAINTENANCE VALVES FOR POWER PLANTS

CONTROL VALVES FOR POWER PLANTS

MIL Controls Limited. The Machining Shop, a part of the world class manufacturing facility at Meladoor near Cochin in Kerala.

© MIL CONTROLS LIMITED, 2002. All rights reserved ABOUT THIS HANDBOOK Forthepast15years,MILControlsLimitedhasbeenoneofthepremiersuppliersofhighspeciality ControlvalvesfortheIndianPowerPlantsector.Overtheseyearsourengineershavegained enormousexperienceinallaspectsofvalvedesign,selectionandmaintenance. The MIL Power Plant Application Handbook triestotranslatethisexperienceintoareadily accessiblereferencetool,theneedforwhichhaslongbeenexpressedbymanyofourclientsand associates.thehandbookthusencapsulatesMIL’scontinuingfocusonthepowersector. Atasecondlevel,TheMILPowerPlantApplicationHandbook,alsoservesasaminicataloguefor MIL’s wide range of products. It offers specific data on Valve Selection and Operational Characteristics. REFERENCE DOCUMENT: ISA HANDBOOK FOR CONTROL VALVES.

MIL Controls Limited A KSB Company RegisteredOffice&Works.Meladoor,Mala,PIN680741,ThrissurDistrict, Kerala,India Tel: 91 (0)488 890272, 890772, 891773. Fax: 91 (0)488 890952. Email: [email protected] MarketingHeadOffice.P.B.No.04,Aluva,PIN683101ErnakulamDist,Kerala,India Tel: 91 (0)484-624955, 624876. Fax: 91 (0)484-623331. Email: [email protected]

APPLICATION HANDBOOK

Contents

Page

1.1 Company overview................................................. 8 2.0 Introduction ........................................................... 9 3.1 Major systems ...................................................... 13 3.2 Condensate system ............................................... 14 3.3 Feed Water system................................................ 17 3.4 Main Steam system ............................................... 22 3.5 Heater Drain system .............................................. 31 4.2 Typical applications. 116 MW ................................ 36 4.3 Typical applications. 210 MW ................................ 38 4.4 Typical applications. 250 MW ................................ 40 4.5 Typical applications.500 MW ................................. 42 5.1 Body material specs ............................................... 47 5.2 Allowableworkingpressure ................................... 48 5.3 Trimmaterialselection ........................................... 51 6.1 Handling&Installation .......................................... 55 7.1 PreventiveMaintenance ........................................ 61 7.2 Shop Overhaul ..................................................... 62 8.1 MIL 21000 Series .................................................. 67 8.2 MIL 41000 Series .................................................. 68 8.3 MIL 78000 Series .................................................. 69 8.4 MIL 91000 Series .................................................. 70 9.0 Index & List of Illustrations ..................................... 72

1.0 Contents

4.1 Typical applications. 67.5 MW ................................ 35

1.1 Company overview


MIL Controls Limited. The factory premises at Meladoor near Cochin in Kerala

E

ver since its inception in 1983, MIL has been unrivalled as a supplier of high performance Control Valves to the Indian power sector.

The company, which stamped its class in it’s very first set of major project supplies to the 210 MW Neyveli TPS (Unit III&IV), the 210 MW MSEB Chandrapur TPS (Stage II), the 210 MW GEB Wanakbori TPS (Stage II) and the 120 MW NALCO CPP (all 5 units) way back in 1984-85, has gone on to excel in the design and manufacture of custom-built special application Control Valves to meet the challenging process control requirements in thermal power stations.

In May 2000, MIL achieved another milestone when it unveiled the MATRIX Series extreme pressure, multi stage, multi path axial flow Control Valves. A product of months of specialised R&D, the MATRIX Series valves have been designed to kill upto 420 Kg/cm2 pressure in 40 stages. This ingenious and unique design has a progressively declining resistance flow path and is designed to eliminate Cavitation and limit Velocity in any severe service condition. In December 2001, MIL had it’s crown of glory when it became the first Indian company to be accredited with the coveted CE marking (refer page 71) for Control Valves, mandatory for exports to the European Union beyond May 2002. The first lot of MIL valves with CE marking is being installed in high pressure steam / Feed Water service in a power plant at Salvimona, Finland being built by M/s Foster Wheeler. Today MIL is the preferred vendor in the country for the rugged, critical application Control Valves for thermal power stations, be it a 33 MW captive power plant or a 250/500 MW utility power plant. With a comprehensive product range, world-class manufacturing and testing facilities, and a highly skilled work force, we are today fully geared to meet any critical process control requirements in the power plant sector.


POWER PLANT APPLICATIONS

Factorsdetermining selectionofValves. usedintheEnergySector.Theiroperational parameters vary widely in terms of pressure, pressure drops, flow rates and temperature. In addition, other crucial factors like Noise, Cavitation, Wire drawing, Leakage Class and Flashing also play an important part in the selection of Control Valves for power station applications. 1. HIGH TEMPERATURE 2. HIGH PRESSURE 3. HIGH PRESSURE DROP 4. COMBINED HIGH TEMPERATURE, PRESSURE & PRESSURE DROP 5. CONTINUOUS THROTTLING 6. TIGHT SHUT OFF CAPABILITIES 7. AERODYNAMIC NOISE 8. HIGH RANGEABILITY 9. CAVITATION AND FLASHING

2.0 Introduction

Extraordinary demands are placed on Control Valves

FIG. 1. GENERAL BOILER (DRUM STYLE) FLOW DIAGRAM

Powerplantapplications 4 major systems, their characteristics and valves used in such applications.


1. CONDENSATE SYSTEM Condensate Pump Minimum Recirculation Valve Deaerator Level Control Valve

2. FEED WATER SYSTEM Boiler Feed Pump Minimum Recirculation Valve. Boiler Feed Water Startup Valve. Boiler Main Feed Water Control Valve.

3. MAIN STEAM SYSTEM SuperheaterAttemperatorSprayValve ReheaterAttemperatorSprayValve. Turbine Bypass Valves. Deaerator Pegging Steam Valves. Soot Blower Steam Pressure Reducing Valves. PRDS System valves

4. HEATER DRAIN SYSTEM High pressure heater drain valves. Low pressure heater drain valves.

3.1 Major systems

The 4 major systems and critical valves .

3.2 Condensate system



Fig. 2. Condensate System.

Condensatesystem The Condensate system consists of the Feed Water Circuit starting from the Condenser Hotwell to the Deaerator. The Condenser is a form of heat exchanger that condenses the exhaust steam of the Turbine. The exhaust steam of the Turbine which is very low in pressure and temperature passes on its heat to the cooling water, is condensed and collects in the hotwell. The low pressure steam which is very high in volume creates a vacuum when it is condensed into water. The vacuum in the Condenser increases the Thermodynamic efficiency of the cycle. The most critical valves which have a bearing on the smooth operation of the plant are Condensate Extraction Pump Minimum Recirculation Valve and Deaerator Level Control Valve.

Condensate RecirculationValve

The Condensate Pump extracts theFeedWaterfromthe CondensateHotwelland dischargestotheDeaerator.

The Condensate Pump must haveaminimmumRecirculation orFlow toavoidoverheatingof thepumpandprotectitfrom Cavitation. The Condensate RecirculationValve recirculates waterfromthepumpbacktothe Condenser toensureminimum Recirculationofthepump.The CondensateRecirculationValve hastoabsorbthefullpressure dropie.,frompumpdischarge pressuretotheCondenser pressure. Due to very near saturatedconditionsexistingin thedownstreamsideofthevalve andrelativelyhigherpressure drops, the valve is subject to Cavitation andFlashing. ControlValvesforthisapplication shouldalsohavegoodshutoff capabilitytoeliminateseat damageduringshutoffconditions. Anyleakageshouldbetakeninto accountasaformoflostenergy.


ThefunctionofthisControlValve istomaintain correctlevelsinthe Deaerator.

Fig. 3. MIL 78000 Series. Condensate Minimum Recirculation Valve. TYPICAL

PARAMETERS

Inlet Pressure: 40- 45 bar( a) Outlet Pressure: 0.1 bar(a) Temperature: 40- 50o C

The typical valves for such applicationshaveantiCavitation featureswhicheliminateany possibilityofCavitationby droppingpressureoverstages. Alsomaterialselectionshouldbe verydiscreteinsuchapplications takingintoaccountofhighly ErosiveCavitatingconditions. Use of 17-4PH and 440C MartensiticSteelhaveyielded excellentresults. The typical valves for such applications are 3” or 4” 78000 Series Multi Step / Multi Stage design or 41008 Series MultiCage/Multi stage design. DeaeratorLevelControlValve.

Theapparentlymildservice conditionsmisleadmanyControl Valvemanufacturersinthe design of valves for this service.

TheFeedWaterlevelinthe Deaeratoralsohelpsin maintainingtheNetPositive Suction Head (NPSH) of the BoilerFeedWaterPump. The DALCV has to cater to the widely varyingflowdemandfrom startupconditionsto fullloadconditions. Valveselectionanddesign should bebasedonthefollowingfactors: Duringthestartupthepump dischargepressurewillbehigh owingtolowflowrequirements. Deaeratorpressureduringthe startupoftheplantwillbelow. These factors result in the valve working at very low Cvs and the associatedlowliftoperations. Alsotherelativelyhigherpressure dropsintheseconditonscanlead tooccuranceofCavitation. Whenthepumppicksupload, theflowrateincreasesandthe pumpdischargepressuregoes down.Atthesametime,theback pressureintheDeaerator increases. This obviously warrants ahigherflowcapacity.


TheDeaeratorisanopencontact typeFeedWaterHeaterwhich purgesanynoncondensableand dissolved gases. Also the Deaeratoractsas areservoirfor FeedWatertosmoothentheFeed Watersupplyatvaryingloads.



Fig. 4. MIL 41000. Deaerator level Control Valve.

Such extremeconditionscallfor valveswithexceptionallyhigh Rangeability,besidesCavitation protectionatlowerflow conditions. Typicaldesignsforsuch applications are the MIL 41921 or the MIL 41621 Series which incorporateanequalpercentage characterizedTrimwhichtakes careofthehighRangeability. The basic design is a Cage Guided PlugwiththeCagehaving characterizedports.

TYPICAL

PARAMETERS

Inlet Pressure: 20- 42 bar (a) Pressure drop: 7- 42 bar (a) Temperature: 50 -100 o C

TheCagedesigncombinessmall sized,drilled,antiCavitationholes inthelowerportion,andlarger holes athigherlifts. This design gives the necessary Cavitationprotectionatlowerlifts andhigherflowcapacityathigher liftsensuring verywide Rangeability.


~

FeedWatersystem The Feed Water system includes those parts of the system from Deaerator to the Boiler inlet. The system consists of Feed Water piping, Feed Water pumps, high pressure heaters and the associated accessories. The Feed Water pressure is raised to the Boiler pressure and the temperature is also raised to near saturation conditions by the high pressure heaters and Economisers. The critical Control Valve applications in this system are Boiler Feed Pump Minimum Recirculation Valve, Boiler Feed Water Startup Valve & Boiler Main Feed Water Control Valve.

BoilerFeedPumpMinimum Recirculation Valve.

Themostcriticalapplicationina PowerStationistheBoilerFeed PumpMinimumRecirculation Service. A pump should have a minimumFlowthroughittotake careofthecoolingrequirements ofthePump.

HenceeveniftheFeedWater requirementsareverylow(dueto lowloadconditions)thepump shouldhandleaminimumflow. Toensurethisminimumflow,a certainamount ofFlowhastobe recirculated backtothe DeaeratorastheFlow requirementsoftheBoilermay notbesufficienttosatisfythe minimumRecirculation requirementsofthepump. Theparametersareobviously verydetrimental foranyvalveto handle. The valve has to drop a pressure of 220-250 bar to 10 bar (Deaeratorpressure).Alsoitmay benotedthat theoutlet conditionsofthevalvearenear saturation,andhencethevalveis verysusceptibleto highenergy CavitationandFlashing. TYPICAL

PARAMETERS

Inlet Pressure: 220-250 bar (a) Outlet Pressure: 10-12 bar (a) Temperature: 200o C

3.3 Feed Water system

Fig. 5. Boiler Feed Pump Minimum Recirculation System.



3 methods of providing Feed Pump Recirculation. 1. The Modulating Type System employsaModulatingValve whichthrottlestheFlowtothe minimumrequiredwhichisa functionoftheFlowrequiredby theBoiler. Supposethe requiredminimum Recirculation of the pump is 100 tons/hr,and theBoiler requirement is 90 tons/hr, the minimumRecirculationvalvewill open so that it passes 10 tons/hr andtheminimumRecirculation condition is satisfied (90 tons/hr throughthemainlineand10 tons/hr through the bypass line. Totalflowthroughthepumpwill be 100 tons/hr ie., 90 + 10). 2. The On/Off System employs an On-Off valve which passes a constantRecirculationFlow. Supposethe requiredminimum Recirculation of the pump is 100 tons/hr,and theBoiler requirement is 90 tons/hr, the MinimumRecirculationValvewill fully open so that it passes 100 tons/hr so that the minimum Recirculationconditionis satisfied.OncetheBoiler requirementgoesabove 100 tons/hr the Recirculation Valve closesfullysincetheBoiler requirementissufficienttosatisfy theminimumRecirculation requirementsofthepump.

3. A third method employed by olderpowerplants, recirculatesa constantflow,regardlessofthe plantload. Thepressureiskilled bySeriesof multiholeplates. Oftheabovemethodstheideal systemwouldbetheModulating System, since it is the most energy efficient . However it exerts taxingdemandsonControlValve functioning. Valvearesubjectedto high pressuredropthrottling ofvery lowflowsto fullflowconditions. Thehighpressuredropthrottling atlowliftconditions adversely affectTrimdurabilityduetowire drawingeffectsandTrimErosion.

Fig. 6. MIL 78000. Boiler feed pump minimum Recirculation valve.


3.3 Feed Water system Fig. 7. MIL 91000. Multi stage multi path, axial flow MATRIX Series valve for Boiler feed pump minimum Recirculation service

In this context, the most cost effectivesolutionisobviouslythe On-Off system. The typical valve for such application is the MIL 78000 Serieswhichincorporatesa uniqueMultiStep,MultiStage designwhichkillspressureovera numberofstages. The 78000 Series ensures a metal to metal Class V leakage. Anothersalientfeatureisthe uniqueSlidingCollarSeatRing designforClassVIleakageshutoff.

MIL’scontinuousresearchand innovationsinPowerPlant applicationvalves hasbornefruit inthesuccessfuldevelopmentof theAxialFlow,MultiStage, VariableResistancedesign,the MATRIX Series Valve which is suitableforaModulatingSystem. Theprototypewasdevelopedfor aPumpRecirculationapplication withpressuredropsof420bar. The salientfeatureofthisdesign isthewidescopeforcustomizing the valve to suit specific process applications.



TheTrimcanbecustomizedto varioushighpressuredrop applicationsbyvaryingthe numberofstages. Thecharacteristiccanbe customizedbyreallocatingthe pressuredropratioindifferent stages. Theexpandingflow passagesalsoenhance the Rangeabilityallowingsmooth andpreciseFlowControlevenat lowliftoperatingflowconditions. FeedWaterRegulatorValve

Anothercritical applicationinthe FeedWaterSystemistheBoiler FeedWaterRegulatingValve which controlsflowtotheBoiler for varying loads of the system. Thevalvetakesthe signalfrom theFeedWaterControlwhich employsathree-elementcontrol. Thesignalisgeneratedasa functionof Drumlevel,Steam flowandFeedWaterflow. Twokindsofvalvesareusedfor FeedWaterregulation. Onevalveisemployedduringthe low loadconditionsorthestartup conditionsoftheBoiler.

Fig. 8. Feed Water Regulating System.

Anothervalveisusedduringfull loadconditions.Apparentlythe applicationsmayseemsimilar. Howevertheselection philosophyanddesignare entirelydifferentforthetwo valves. This is because of the differentpressuredropconditions existingatthetimeofStartupand Full Load. ThetypicalparametersofLow LoadFeedWaterControlValve andFullLoadFeedWaterControl Valvearegivenbelow. LOW LOAD FEED WATER VALVE TYPICAL

PARAMETERS

Inlet Pressure: 170-200 bar (a) Outlet Pressure: 30-110 bar (a) Temperature: 230o C FULL LOAD FEED WATER VALVE TYPICAL

PARAMETERS

Inlet Pressure : 220-250 bar (a) Outlet Pressure: 210- 230 bar (a) Temperature: 247o C



Fig. 9. MIL 41008. Multi stage, Low Load, Feed Water regulating valve.

Thetypicaldesignforlowloadandfullloadapplicationsisthe MIL 41000 Series Valves which employ Heavy Duty Cage Guided features. TheCageGuideddesignensures goodThrottlingStabilityandgood Rangeabilitytocatertowidelyvaryingflowconditions. Wherethepressuredropduringstart-upconditionisveryhigh,which can be detrimental in conventional valves, 41008 Series Multi Cage designfindsitstypicalapplicationforthelowloadvalve. ThisdesignwhichfeaturesaMultiStagePressureDropTrim,willtake careoftheveryhighpressuredropsencounteredduringstart-up conditionswherethedrumpressureisverylowandthepump dischargepressureisveryhigh.

3.4 Main steam system


Fig. 10. Critical Control Valves in Main Steam Line

MainSteamSystem The Main Steam System consists of the steam circuit from the Boiler outlet, Superheater System, Soot Blowing system, Turbines, Reheater System to Condenser. The steam fully extracted of the energy is finally dumped into the Condenser, which is the heat sink. The most critical application valves in this system are: Superheater Spray Control Valves, Superheater Spray Block Valves, Reheater Spray Control Valves, Reheater Spray Block Valves, Soot Blower Pressure Control Valves, PRDS System Control Valves, Main Steam Pressure Reducing Valves, PRDS Spray Control Valves and Deaerator Pegging Steam Valve.

SuperHeaterAttemperatorValve

Thetemperature ofthemain steamcomingoutoftheBoileris verycritical fromthepointof Thermodynamic Efficiencyofthe heatcycleandtheTurbineblade protection.

Boilermanufacturersemploy variousmethods likeburnertilt mechanism, spray water systems etc.tocontrolthetemperatureof the Main Steam . A poor temperaturecontrolsystemmay resultindamagestoTurbine blades,Superheatertubes, Reheatertubesetc. Hence Attemperator valves are of critical relevance The typicalproblemsfacedby superheatersprayControlValves arethrottlinginstability andwide Rangeability. The designparametersofthe spray system include those conditions whichaccountforthe excessiveheatingoftheTurbine atfull load,withtheFeedWater atitsmaximumtemperature, cleanBoilertubesandmost favourableconditions.


Fig. 12. MIL 41200. Superheater Attemperator valve.


Fig. 11. MIL 41100. Superheater Attemperator valve.



Howevertheaboveconditions seldomcomeintoplaydueto deteriorationofBoilertubesdue toScalebuildupandthe consequentheattransferloss. Alsothesituationisfurther compoundedby withdrawalof heat throughtheSootBlower.All thesefactorsresultinadrastic reductionofspraywater requirements. Hence in practice the Spray WaterValvewillbeseldomtaken intofullcapacity.Thevalvewillbe workingatlowerliftconditions duetoabovesaidreasons. Anothercriticalfactorinfluencing theselectionofControlValveis the Leakage Class. Anyexcessiveleakagewillresult inthermalshocksin Secondary SuperheaterTubesanderosionof Turbineblades. MIL offers special designs like the 41100 Series and the 41200 Seriesforsuchapplications. The 41100 Series features an unbalancedCageGuideddesign. Thiscombinesthetwinbenefits ofthegoodthrottling stability of Cage Guided valves with the shut offcapabilityofsingleseated unbalanceddesigns. TYPICAL

PARAMETERS

Inlet Pressure:181-200 bar (a) Outlet Pressure: 161-180 bar (a) Temperature: 247o C

Fig. 13. MIL 41400. Superheater Attemperator block valve.

For higher sizes (2” and above) theActuator thrustrequirements willbeveryhighduetothe unbalanced design of the 41100 Seriesdesign. The 41200 features a balanced design withanovelStaticSeal concept. The 41200 design has thesameadvantagesthatthe 41100 Series besides the added featureofabalancedplug. AnotherapplicationofSpray System is the block valve. The block valves assists the spray ControlValves effectingatight shutoff.Another requirementof a block valve is faster response. Hence the Spray System employs apneumaticallyoperatedOnOff ControlValveforthisapplication. The typical MIL designs for block valve applications are the 41400 Series and the 41200 Series. The 41400 design is a Cage Guided designwherethemainplugis assistedbyanauxiliarypilotplug toeffecttightshutoff.


Fig. 15. MIL 41008. Reheater Attemperator Control Valve.

ReheaterAttemperatorValves

ThesourceoftheSprayWater caneitherbetheFeedWater pumpoutletortheinterstage tappingofthepump. Incaseoftheformer,thepressure drop can be as high as 100-120 bar, andlatter,itcanbeupto 60-70 bar. The MIL solution to such applications are the 78000 Series or the 41128 Series for high pressure drops (100-120 bar). In thecaseofmoderatepressure drops, it is the 41121 Series or the 41221 Series. TheReheaterSprayBlockValve applicationissimilarto SuperheaterSprayBlock applications,andtheselection philosophyissimilartothatfor SuperheaterSprayBlockservice.

Thisapplicationisalsosimilarto theSuperheaterSprayControl Valveapplication. However fluctuationsin temperatureis notvaryingasin SuperheaterSprayControl. The Leakage Class is very critical since excessive leakage can lead toErosionoflowpressureTurbine blades. Thevalveselectiondependson thepressuredropacrossthe valve.Itmaybenotedherethat reheaterpressureistheoutlet pressureofthehighpressure Turbine. Thepressuredropacross thevalvedependsonthesource ofthespraywater.


Fig. 14. MIL 78000. Reheater Attemperator Control Valve.



Fig. 16. Deaerator Pegging Steam System.

DeaeratorPeggingSteamValve

TheDeaerator isadirectcontact typeheaterwhichremovesnon condensable gases like Oxygen andCarbondioxidefromthe Feed Water. These gases, if not expelled,willattackandcorrode pipingandBoilertubes.Thehot steamismixedwiththeFeed WaterenteringtheDeaerator bringingittosaturation temperatureandthereby liberatinganyundissolvedornon condensablegases. Steamissupplied tothe Deaeratorfordeaeration ofFeed Waterandalsotomaintaina positivepressureinthe Deaearator.Deaerator actsasa FeedWaterstoragetanktothe BoilerFeedPump.Maintaininga higherpressureintheDeaerator helpsinmaintainingtheNPSHof thepump.

Normallythesteamistakenfrom theAuxiliarySteamHeaderupto 15% MCR condition. Above this and upto 40% MCR, the steam is takenfromtheColdReheat Header(Steamtappedafterthe HighPressureTurbine).Infull loadconditions,steamistaken directlyfromtheTurbine extractionline. Typical valves in this system are: 1. DEAERATOR PEGGING FROM AUXILLIARY STEAM HEADER TYPICAL

PARAMETERS

Inlet Pressure: 16 bar (a) Outlet Pressure: 3.5 bar (a) Temperature: 220o C 2. DEAERATOR PEGGING FROM COLD REHEAT STEAM HEADER TYPICAL

PARAMETERS

Inlet Pressure: 21 bar (a) Outlet Pressure: 3.6 bar (a) Temperature: 330o C


SootBlowerValve

Theproblemsencounteredin valve selection for such applicationsare thehighnoise levels associated with this valve. MIL offers special low noise Trims (Lo-dB Design) for such applications. The 41000 Series Cage Guided valves with special LowNoiseTrimhavebeenfound excellent for such services. Additionalnoiseattenuationcan beachievedwithdouble stage pressuredropdesignssuchas doubleCageordiffuseroptionsin the 41000 Series. Anotherproblemassociatedwith this service is high exit velocities duetovolumetricexpansionof thesteamwhenthepressure drops. MIL offers special low noisecartridges whichdividethe pressuredropbetweenthevalve andthecartridges. Theeffectivepressuredropratio across the valve is reduced which resultsinlowexitvelocitiesand noiselevels.

Oneofthemajorchallengeshere is to select and design a Control ValvefortheSteamSootBlowers. Theproblemsuniquetothis serviceareHighpressuredrop, HighnoiselevelsandThermal cycling of the valve body and valveinternals. Sootblowingvalvesarenormally isolatedbyanupstreamisolation valve. Hence the valve is not subjectedtohighpressureand temperature whennotinservice. HoweverwhentheSootBlowing is being done, the valve is subjected to very high pressures andtemperatures. TYPICAL

PARAMETERS

Inlet Pressure - 170 bar (a) Outlet Pressure - 20 bar (a) Temperature - 540o C


Fig. 17. MIL 41003. Deaerator pegging steam Control Valve

Theeffectivenessoftheheat transferthroughBoilertubesis adverselyaffectedbythebuildup ofsoot.Alsotherapidbuildupof sootinthetubescanleadtothe developmentofhotspotsinthe Boilertubes.TheBoilertubes shouldbefrequently cleaned to remove thesoot.Thenormal practice is to use high velocity steamjetstoblowthesootfrom the tubes. The soot removal is effectedthroughSootBlowers. SomeSootBlowersuseairalsofor theremovalofsoot.



Fig. 18. MIL 71114. Soot blower pressure reducing Control Valve

Hence the valve is subjected to thermal cycling which can cause WarpageandCreepinthe conventional castglobevalve bodies. Theobvioussolutionwouldbeto useforgedanglebodiesorforged inlinebodieswithspecialmulti stagelownoiseTrims.

Here MIL offers it’s 41114 Series (CageGuidedinlinebodywith doublestagepressuredrop),or it’s 71114 Series (Cage Guided anglebodywithdoublestage pressuredrop).Thebodyshallbe forgeddesignandchrome molybdenum steel (ASTM A 182 Gr. F22)


PRDSStationValves.

Apartfromsteambeingusedfor powergenerationandsoot blowing,steamisusedforother auxiliaryserviceslikegland sealingofTurbines,Steam EjectorsinCondensersand Deaerator pegging. Themainsteamhastobe Desuperheatedbyreducingits pressureandtemperature to utilisethesteamfortheabove mentionedapplications. MAIN STEAM PRESSURE REDUCING VALVE TYPICAL

PARAMETERS

ThesteamDesuperheating is effectedthroughPRDSstations– PressureReducing DesuperheatingSystem. The PRDS system consists of a Desuperheaterpressurereducing valveandatemperatureControl Valve. Thepressurereducing valvereducesthepressureofthe steambeforeentryintothe Desuperheater. ThetemperatureControlValve regulatesthespraywater quantityintotheDesuperheater. TEMPERATURE CONTROL VALVE (SPRAY WATER) TYPICAL

PARAMETERS

Inlet Pressure - 170 bar (a)

Inlet Pressure - 185 bar (a)

Outlet Pressure - 16 bar (a)

Outlet Pressure - 16 bar (a)

Temperature - 540o C

Temperature - 170o C


Fig. 19. Typical Auxiliary PRDS System



Fig. 20. MIL 41914 Main Steam Pressure Reducing Valve.

The critical factors that govern selection of Main Steam PRV are: High pressure drop, High temperature, High noise levels and Material selection for high temperature.

A seat ring - basket diffuser is provided foreffectivenoise attenuationathigherpressure dropratios.

ThetemperatureControlValveis anothercriticalvalvecomingin MIL offers the 41912 Series or the the system. As in the case of 41914 Series for this application. ReheaterSprayControlValve, ThisdesignfeaturesaCage the selection of this valve is also GuidedTrimwith specialLow governedbythe sourceofthe Noisemultipleholescontrolling SprayWater.Thesourceofthe theflow.Optionaldoublestage SprayWatercaneitherbefrom designisalsoavailablewhichis FeedWaterPumpoutletorinter veryeffectiveinnoiseattenuation stagetappingofthepump. athigherpressuredropratios. Inthecaseoftheformer,the For Class V leakage, the 41413 pressuredropcanbeashighas Series istheappropriate 100-120 bar, and in the latter selection. The 41413 Series case, it can be upto 60-70 bar. design is a Cage Guided design wherethemainplugisassistedby The MIL solution to such applications are the 78000 Series an auxiliarypilotplugtoeffect or the 41128 Series for high thetightshutoff. pressure drops (100-120 bar). The Cage design includes Inthecaseofmoderatepressure multipleholestoattenuatethe dropsthe designshallbethe noise.Theflowdirectionofthe 41121 Series or the 41221 Series. valve is Over the Plug.


Thecriticalfactorsthat influence theselectionofthevalvesare: Body andTrimmaterial,Valve sizeandValveflowcapacity

The liquid dropletsaccelerated byrelativelyhighvelocityvapour Fig. 21. MIL 21000. Heater Drain Valve phase,impingesonthematerial surface ofbodyand Trimcausing TheHeaterDrainSystem The heater drain system consists of heavywear. the Feed Water heaters coming in the Condensate system and Feed Water system. The Feed Water heaters coming in the Condensate system are called low pressure heaters which heats the Condensate to saturation point before entry into Deaerator. The heaters coming in the Feed Water system are the High pressure heaters which heat the Feed Water to near saturation point before the entry into Boiler. The HP heaters and LP heaters are basically heat exchangers – shell and tubetype. The heating media for HP heaters is the steam extracted from the reheat cycle, whereas for LP heaters the steam is extracted from the low pressure Turbine.

GenerallyChromeMolybdenum steelshaveexhibitedexcellent resistancetoFlashingErosion. Even though ASTM A 217 Gr C5 is recommended by some users, it isbeing increasinglyreplacedby ASTM A 217 Gr WC9 material as C5 has some significant manufacturingproblems,in additiontopoorweldability,and isthusdifficulttoweldrepair.

Anotherissueistheselectionof valve body size. It is always recommendedtoselecthigher The heating media, i.e., the steam is bodysizeswithareduced introduced into the heaters, cooled capacityTrim. and ultimately condensed back to liquid. The level in the heaters are to be closely controlled to maintain the Thermodynamic efficiency of the system. The Condensate in the heaters are at saturation condition, and when the Condensate is drained to either Deaerator or the Condensate flash tank, the fluid losses pressure and flashes.

Thebodysizeselectioncriteriais theoutletFlashingvelocity. MIL offers it’s 21000 Series and the 4100 Series Valves for these applications. Thebodymaterialis either WC6 or WC9.

3.5 Heater drain system

Flashingproblemsencountered intheseservicescausematerial erosion.

3.5 Heater drain system


Fig. 22. LP Heaters System

Fig. 23. HP Heaters System

TypicalInstallations Choosingtherightvalvemakesallthedifference

FW-2

FW-8

1

2

3

FULL LOAD FEED WATER FLOW CONTROL (BY-PASS)

FULL LOAD FEED WATER FLOW CONTROL

LOW LOAD FEED WATER FLOW CONTROL

Service

SD-5.SD-6

SD-23

SD-7

S57. S69

SB4

SD-8

1

2

3

4

5

6

Tag

AS-9

AS-3

BV-01

SW-10

SW-4

No.

1

2

3

4

5

PRDS VALVES

Tag

No.

LOW CAPACITY SPRAY WATER CONTROL VALVE

HIGH CAPACITY SPRAY WATER CONTROL VALVE

COMMON BLOCK VALVE FOR PRDS SPRAY

LOW CAPACITY STEAM PRESSURE REDUCING

HIGH CAPACITY STEAM PRESSURE REDUCING

Service

SOOT BLOWER STEAM PR.REDUCING VALVE


SH SPRAY BYPASS VALVES

INTERMITTENT BLOWDOWN VALVE

SH SPRAY BLOCK

SH SPRAY CONTROL

Service

SPRAY & SOOT BLOWER VALVES

Tag

FW-5

No.

FEEDWATER CONTROL VALVES Size 3 in.

1500

1500

1500

Rating*

2 in.

2 in.

2 in.

Size

2 in.

2 in.

2500

2500

1500

1500

1500

1500

Rating*

Size

2 in.

2 in.

38-78101

1 in.

38-78101 1.5 in.

37-211X4

38-41412

38-41912 6x3 in.

Model

1500

1500

1500

1500

1500

Rating*

Project: TISCO 1X67.5MW

38-70571

38-70571

90-41024 2.5 in.

38-78001

38-414X1

38-41024

Model


90-41921 6x3 in.

38-41921 6x3 in.

38-78101

Model


A105

A105

WCC

WC9

WC9

Body

F22

F11

WCC

A105

WCC

WCC

Body

WC6

WC6

F11

Body

0.3

1.2

15

12

120

Cv

10

6

20

4

40

8

Cv

140

140

15

Cv

Temp.

1

1

1

Qty.

4

2

4

2

0

185 kg/cm 150 C 2

0

185 kg/cm 150 C 2

0

185 kg/cm 175 C 2

0

100 kg/cm 520 C 2

* ANSI

1

1

1

1

1

100 kg/cm 520 C 0

Qty. 2

Temp.

Pr.

Customer:BHEL Madras

110 kg/cm2 4200C

173 kg/cm2 4130C

0

186 kg/cm 242 C 2

0

110 kg/cm 350 C 2

185 kg/cm 250 C 0

2

4 2

185 kg/cm 250 C 0

Qty. 2

Temp.

Pr.

Customer: BHEL Trichy

0

0

170 kg/cm 235 C 2

2

170 kg/cm 235 C

170 kg/cm2 2350C

Pr.

Customer: BHEL Madras

4.1 Typical applications. 67.5 MW

Capacity 67.5 MW


CV-5.6

CV-7.8

CV-9.10

1

2

3

CV-11.12

CV-13.14

CV-15.16

CV-17.1

1

2

3

4

Tag

CV-23

CV-24

No.

1

2

PRDS VALVES

Tag

No.

SPRAY VALVES

Tag

No.

FEED CONTROL VALVES

Capacity 116 MW

PRDS SPRAY CONTROL VALVE

PRDS PR. REDUCING VALVE IN HP STEAM LINE TO AUX.HDR.

Service

LP BYPASS SPRAY VALVES

LP STEAM BYPASS VALVES

HP BYPASS SPRAY VALVES

HP STEAM BYPASS VALVES

Service

FEED REGULATING VALVE IN HP BFP DISCH.LINE (LOW LOAD)

FEED REGULATING VALVE IN HP BFP DISCH.LINE (FULL LOAD)

FEED REGULATING VALVE IN HP BFP DISCH.LINE

Service

2 in.

3 in.

2 in.

Size

900

900

300

Rating*

A105

WC6

WCC

Body

1 in.

8 in.

2 in.

6 in.

Size

600

150

600

1500

Rating*

WCC

WCC

WCC

WC6

Body

38-78003

38-41412

Model

1 in.

2 in.

Size

900

1500

Rating*

A105

WC6

Body

Project: Ahemedabad Electricity Company.

38-211X5

38-41421

37-211X5

38-41412

Model


38-78001

37-41612

38-41621

Model


0.3

30

Cv

3.8

640

46

145

Cv

4

95

26

Cv

2 2 2

115 kg/cm 121 C 115 kg/cm 120 C o

o

Qty. 2 2 2 2

480 C o

50 C 147 C 50 C

2 2 2

o

o

1

119 kg/cm 121 C o

* ANSI

1 2

480 C

70 kg/cm

o

Qty. 2

Temp.

Pr.

Customer:BHEL Bangalore

13 kg/cm

7 kg/cm

13 kg/cm

o

Temp. 2

70 kg/cm

Pr.


2

2

121 C

15 kg/cm

0

Qty.

2

Temp.

Pr.

Customer: BHEL Bangalore

4.2 Typical applications. 116 MW


CV-25.26.27

CV-28.29.30

1

2

RECIRCULATION VALVE FOR LP BFP

RECIRCULATION VALVE FOR HP BFP

Service

Tag

CV-1

CV-2

CV-3

CV-4

CV-19

CV-20

CV-21.22

CV-31

CV-32

No.

1

2

3

4

5

6

7

8

9

DUMP MAKE-UP VALVE

NORMAL MAKE-UP VALVE

PREHEATER INLET CONTROL VALVE

PRESSURE REDUCING VALVE TO DEAERATOR

PRESSURE REDUCING VALVE TO DEAERATOR

DEAERATOR OVERFLOW TO DM STORAGE TANK

EXCESS RETURN CONTROL VALVE

MIN. FLOW RECIRCULATION CONTROL VALVE

MAIN CONDENSATE CONTROL VALVE

Service

HEATER DRAIN VALVES & CONDENSATE SYSTEM VALVES

Tag

No.

FEED PUMP RECIRCULATION VALVES Size

1in.

600

900

Rating*

WCC

A105

Body

38-21125

37-21125

37-41621

38-41621

38-41621

38-414X1

37-41621

37-41612

38-41621

Model

2 in.

1 in.

4 in.

8 in.

3 in.

3 in.

2 in.

2 in.

6 in.

Size

600

600

300

150

150

150

300

300

300

Rating*

CF8M

CF8M

WCC

WCC

WCC

WCC

WCC

WCC

WCC

Body


37-211X5

37-78003 1.5 in.

Model


46

6

225

500

95

155

65

25

360

Cv

3.8

4.5

Cv 2

18 kg/cm

122 C o

3

3

Qty.

48 C o

48 C 120 C 147 C 147 C 118 C

2 2 2 2 2

10 kg/cm2

10 kg/cm2

13 kg/cm

7 kg/cm

7 kg/cm

7 kg/cm

13 kg/cm

40oC

40oC

o

o

o

o

o

13 kg/cm

48oC 2

Temp. 13 kg/cm2

Pr.

* ANSI

1

1

2

1

1

1

1

1

1

Qty.


2

o

Temp.

115 kg/cm 122 C

Pr.

Customer: BHEL Bangalore


Capacity 116 MW


FW-FCV-1

1

FULL LOAD FEED WATER FLOW CONTROL (MAIN&BYPASS)

Service

SD-4

SD-5.6.7.8

SD-9

SD-10.11.12.13

SD-14

SD-15.16.17.18

SD-19.20.21.22

PCV-8502A.B

1

2

3

4

5

6

7

8

Tag

MSPCV-1

MSPCV-2

SPTCV-1

SPTCV-2

V2505111

No.

1

2

3

4

5

PRDS VALVES

Tag

No.

BLOCK VALVE ON SPRAY WATER TO AUX. PRDS

AUX.PRDS 10%SPRAY FLOW CONTROL VALVE

AUX.PRDS 100%SPRAY FLOW CONTROL VALVE

AUX.PRDS 10%STEAM PR. CONTROL VALVE

AUX.PRDS 100%STEAM PR. CONTROL VALVE

Service


RH CONTROL

RH BLOCK BRANCH

RH BLOCK COMMON

SH STAGE II CONTROL

SH STAGE I I BLOCK

SH STAGE I CONTROL

SH STAGE I BLOCK

Service

2 FW-FCV-2 LOW LOAD FEED WATER FLOW CONTROL SPRAY & SOOT BLOWER VALVES

Tag

No.

FEED CONTROL VALVES

Capacity 210MW Size 2500

Rating* WC6

Body

Size

2 in.

2500

2500

2500

2500

2500

2500

2500

2500

Rating*

Size

2 in.

37-211X4

38-78101

2 in.

1 in.

38-78102 1.5 in.

38-41012

38-41412 6x3 in.

Model

2500

2500

2500

2500SPL

2500SPL

Rating*

Project : Raichur TPS. Unit IV

38-41012

38-78103 1.5 in.

38-410X4 1.5 in.

38-410X4 2.5 in.

38-41024 1.5 in.

38-410X4 2.5 in.

38-41024 2.5 in.

38-410X4 6x4 in.

Model

WCC

A105

A105

15

0.3

2.4

6

50

WC9 WC9

Cv

25

3.6

40

60

3.8

60

30

195

Cv

45

575

Cv

Body

F11

A105

WCC

WCC

WCC

WCC

WCC

WCC

Body

38-41412 6x4 in. 2500 WC6 Project : Unchahar TPS 2x210 MW

38-41921 12x8 in.

Model

Project : Raichur TPS Unit IV

2

2

Qty.

2 8

265 kg/cm 260 C

8 8 4

265 kg/cm 260 C 185 kg/cm 440 C o

* ANSI

1

286 kg/cm 250 C o

1 2

286 kg/cm2 250oC

1

1 286 kg/cm2 250oC

1

Qty.

165 kg/cm2 540oC

Temp. 165 kg/cm2 540oC

Pr.

Customer:BHEL Madras

2

o

265 kg/cm2 260oC 2

2

o

265 kg/cm2 260oC

2

o

o

265 kg/cm 260 C 2

2

8

Qty.

265 kg/cm 260 C

o

Temp.

2 2

o

265 kg/cm 260 C

Pr.

2

1 285 kg/cm 250 C Customer:BHEL Trichy

o

Temp.

286 kg/cm 250 C

Pr.

Customer: BHEL Madras



Tag

FEED PUMP MINIMUM RECIRCULATION

Service

Tag

PAS-1

PCR-1

DR-2

DR-6

DR-9

DR-12

DR-15

DR-17

DR-20

DR-22

DR-25

DR-41

CD-14

CD-23

CD-19

CD-78

DM-1

DM-2

CD-47

No.

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

CONDENSATE FOR VALVE GLAND SEALING

DM MAKE-UP TO HOTWELL (HC)

DM MAKE-UP TO HOTWELL (LC)

HP DRAINS MANIFOLD SPRAY

CONDENSATE MINIMUM RECIRCULATION

CONDENSATE EXCESS RETURN

MAIN CONDENSATE

DEAERATOR OVERFLOW TO DRAIN TANK

LPH-2 DRAIN TO FLASH BOX-1

LPH-2 DRAIN TO LPH-1

LPH-5 NORMAL DRAIN TO FLASH BOX-1

LPH-3 NORMAL DRAIN TO LPH-2

HPH-5 NORMAL DRAIN TO FLASH BOX-2

HPH-5 NORMAL DRAIN TO DEAERATOR

HPH-6 NORMAL DRAIN TO FLASH BOX-2


HPH-6 NORMAL DRAIN TO HPH-5

PEGG. STEAM FROM CRH TO DEAERATOR

PEGG. STEAM FROM AUX. STEAM HEADER TO DEAERATOR

Service

HEATER DRAIN VALVES & CONDENSATE SYSTEM VALVES

1

No.

FEED PUMP RECIRCULATION VALVES Size 2500

Rating* A105

Body

10 in.

10 in.

8 in.

8 in.

4 in.

3 in.

4 in.

4 in.

3 in.

3 in.

3 in.

3 in.

2 in.

1 in.

6 in.

38-41621 1.5 in.

37-41611

37-41611

37-211X5

37-78003

300

300

300

300

300

300

300

300

300

300

300

300

300

300

600

600

600

600

300

6 in. 10 in.

Rating*

Size

38-41612 6x4 in.

38-41621

38-416X1

37-41621

38-41621

37-41621

38-41621

38-41321

38-41321

38-41321

38-41321

38-41321

38-41912

38-41912

Model

WCC

CF8M

CF8M

WCC

A105

WCC

WCC

WCC

WCC

WCC

WCC

WCC

WC6

WC6

WC6

WC6

WC6

WCC

WCC

Body

Cv

15

Cv

14

60

30

12

70

145

900

1000

575

575

225

140

90

90

56

56

56

430

300

Project : Vijayawada TPS Stage II Unit V&VI

37-78103 4x2 in.

Model

Project : Ropar TPS

2

2

Qty.

2

230 C 350 C 215 C

2 2

180 C 130 C 130 C 100oC

2 2 2

170 C o

55 C 55 C

2 2

50 C o

50 C 55 C

2 2

25 kg/cm

10 kg/cm

o

o

10 kg/cm

55oC 2

55oC

o

25 kg/cm2

25 kg/cm2

25 kg/cm

25 kg/cm

11 kg/cm

2

o

100oC

o

o

8 kg/cm2

8 kg/cm

8 kg/cm

8 kg/cm

20 kg/cm

o

180 C 2

20 kg/cm

2

o

48 kg/cm2 215oC

48 kg/cm2 215oC

o

o

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

Qty. o

Temp. 2

48 kg/cm

48 kg/cm

20 kg/cm

Pr.

Customer:BHEL Delhi

o

Temp.

260 kg/cm 250 C

Pr.

Customer: BHEL Hyderabad


Capacity 210 MW


0728.1&2

728.3

1

2


FULL LOAD FEED WATER FLOW CONTROL (MAIN&BYPASS)

Service

SD-4

SD-5 TO SD-8

SD-9

SD-10 TO SD-13

SD-14

SD-15 TO SD-18

SD-19 TO SD-22

SD-23

1

2

3

4

5

6

7

8

AS-22

FD-22

FD-23

AS-32

FD-29

FD-30

1

2

3

4

5

6

Tag

No.

PRDS VALVES

Tag

No.

CRH PRDS SPRAY CONTROL

CRH PRDS SPRAY CONTROL

CRH STEAM PRDS

MS PRDS SPRAY CONTROL

MS PRDS SPRAY CONTROL

MS PRDS STEAM CONTROL

Service


RH SPRAY CONTROL

RH BRANCH BLOCK

RH SPRAY MAIN BLOCK

SH STAGE II SPRAY CONTROL

SH STAGE II SPRAY BLOCK

SH STAGE I SPRAY CONTROL

SH SPRAY STAGE I BLOCK

Service


Tag

No.

FEED CONTROL VALVES

Capacity 250 MW Size

2500

2500

Rating*

WC6

WC6

Body

2in.

2in.

2in.

3in.

1.5in.

3in.

2.5in.

6in.

Size

2500

2500

2500

2500

2500

2500

2500

2500

Rating*

F22

F11

WC6

WC6

WC6

WC6

WC6

WC6

Body

Size

38-78001

38-78001

38-41012

38-41024

38-78002

1in.

1in.

2.5in.

1.5in.

1.5in.

38-41412 6x4in.

Model

2500

2500

600

2500

2500SPL

2500SPL

Rating*

A105

A105

WCC

WCC

A105

WC9

Body

Project : BSES DAHANU 2x250 MW

38-70571

38-78003

38-211X4

38-414X1

38-41024

38-414X1

38-41024

38-414X1

Model

Project : BSES DAHANU 2x250 MW

38-41921 6x4in.

38-41921 14x10in.

Model

0.3

0.3

20

6

2.4

110

Cv

13

3.5

15

30

8

75

30

240

Cv

225

900

Cv

Project : CESC Budge Budge TPS. 2*250 MW

o

8 2 8

182 kg/cm 350 C 282 kg/cm 350 C 282 kg/cm 350 C o

o

2

2

2 2

267 kg/cm 170 C 2

o

o

267 kg/cm 170 C 2

2

2

2

2

Qty.

48 kg/cm2 360oC

267 kg/cm2 170oC

267 kg/cm2 170oC

o

Temp. 169 kg/cm 545 C

Pr.


182 kg/cm2 450oC

182 kg/cm2 350oC

2

2

o

8

2 2

o

o

262 kg/cm 350 C 2

2

8

Qty.

182 kg/cm 260 C

o

Temp.

2 2

262 kg/cm 260 C

Pr.

Customer:BHEL Trichy

2

2

Qty.

330 kg/cm 248 C

o

Temp.

4 2

330 kg/cm 248 C

Pr.

Customer: BHEL Delhi



AS-2

CRH-2

DR-2

DR-6

DR-9

DR-13

DR-16

DR-19

DR-22

DR-25

DR-28

DR-38

CD-14&CD-17

CD-25

CD-21

CD-53

CD-58

DM-2 (LOW)

DM-5 (HIGH)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

DM MAKE-UP TO HOTWELL (HC)

DM MAKE-UP TO HOTWELL (LC)

EMERGENCY MAKE-UP TO CONDENSATE HOTWELL

HP DRAINS FLASH TANK SPRAY

EXCESS CONDENSATE DUMP CONTROL

CONDENSATE EXCESS PUMP MIN. RECIRCULATION

MAIN CONDENSATE CONTROL

DEAERATOR OVERFLOW TO LP FLASH TANK

LPH-2 ALT. DRAIN TO LP FLASH TANK


LPH-3 ALT. DRAIN TO LP FLASH TANK


HPH-5 ALT. DRAIN TO HP FLASH TANK


HPH-6 ALT. DRAIN TO HP FLASH TANK

HPH-6 ALT. DRAIN TO DEAERATOR

HPH-6 NORMAL DRAIN TO HPH-5

PEGG. STEAM FROM CRH TO DEAERATOR

PEGG. STEAM FROM AUX. STEAM HEADER TO DEAERATOR

HEATER DRAIN & CONDENSATE SYSTEM VALVES

A105

3 in.

12 in.

3 in.

8 in.

8 in.

4 in.

4 in.

4 in.

4 in.

3 in.

3 in.

3 in.

10 in.

8 in.

37-41612

37-41512

37-41612

37-211X5

4 in.

3 in.

3 in.

1 in.

38-41612 6x3 in.

37-78003

38-41521

38-419X1

37-41621

38-41521

37-41621

38-41521

37-41921

38-41521

37-41921

38-41921

38-41521

38-41912

38-41912

150

300

150

300

300

600

300

300

150

150

150

150

300

300

600

600

600

600

300

CF8M

CF8M

WCC

WCC

WCC

A105

WCC

WCC

WCC

WCC

WCC

WCC

WC6

WC6

WC6

WC6

WC6

WCC

WCC

Project : Kothagudem TPS, 2*250 MW

2500

37-78103 4x2 in.

1

120

45

95

1,7

95

45

900

100

575

575

170

170

120

120

56

50

50

500

315

15

215 C

170 C o

55 C o

55 C o

55 C o

55 C o

55 C o

40 C 40 C

2 2 2 2 2 2 2

8 kg/cm

8 kg/cm

8 kg/cm

30 kg/cm

27 kg/cm

27 kg/cm

27 kg/cm

11 kg/cm

o

o

105oC 2

105oC

130oC

130oC

8 kg/cm2

8 kg/cm2

8 kg/cm2

8 kg/cm2

20 kg/cm2 175oC

20 kg/cm2 175oC

48 kg/cm2 215oC

48 kg/cm2 215oC

o

360 C 2

48 kg/cm

48 kg/cm

2

o

14 kg/cm2 220oC

Customer: BHEL Delhi

260 kg/cm2 250oC

Customer: BHEL Hyderabad


FEED PUMP MINIMUM RECIRCULATION

Project : Kothagudem TPS, 2*250 MW

FEED PUMP RECIRCULATION VALVES

Capacity 250 MW

2

2

2

2

2

2

4

2

2

2

2

2

2

2

2

2

2

2

2

2


FCV-0657

1


Service

SD-10

SD-11 TO SD-14

SD-15

SD-16 TO SD-19

SD-20 TO SD-23

SD-24

1

2

3

4

5

6


RH SPRAY CONTROL

RH BRANCH BLOCK VALVE

RH SPRAY BLOCK

SH SPRAY CONTROL

SH SPRAY BLOCK

Service

LCV-0507

LCV-0508

5

6

CONDENSATE NORMAL MAKE-UP

CONDENSATE SPILL TO CONDENSATE STORAGE TANK

CONDENSATE FLOW TO DEAERATOR

FCV-0559A/B

CRH FLOW TO DEAERATOR

4

PCV-0326B

2

AUX. STEAM TO DEAERATOR

CONDENSATE PUMPS A.B.C MINIMUM FLOW RECIRCULATION

PCV-0326A

1

Service

3 FCV-01514/0519/0524

Tag

No.


Tag

No.


Tag

No.

FEED CONTROL VALVES

Capacity 500 MW Size 2500

Rating* C5

Body 475

Cv

8 in.

Size

3 in.

2500

2500

2500

2500

2500

2500

Rating*

F11

WCC

WCC

WCC

WCC

WCC

Body

25

12

75

155

26

380

Cv

37-41621

38-41612

38-41521

37-78103

38-41512

37-41512

Model

4 in.

8 in.

10 in.

4 in.

300

300

300

600

600

300

12 in. 16 in.

Rating*

Size

CF8M

WC6

WCC

A105

WC6

WCC

Body

140

315

900

55

1200

725

Cv

Project : NTPC Talcher TPS 2x500 MW STPP

38-41012 4x2 in.

38-41024 2.5 in.

38-414X1

38-414X1 4x3 in.

38-41621 4x3 in.

38-414X1

Model

Project : NTPC Vindhyachal TPS 2x500 MW STPP

37-41512 12x8 in.

Model

Project :NTPC Talcher TPS 2x500 MW STPP

2

2

Qty.

Temp.

2 8 8 4

340 kg/cm 260 C 340 kg/cm 260 C 213 kg/cm 482 C o

o

o

2 2

295 C 410 C 2

* ANSI

2

40 C 2

10 kg/cm

2

50oC 47 kg/cm2

o

4

47oC

47 kg/cm2

47oC

o

6

Qty. o

Temp. 2

47 kg/cm2

57 kg/cm

20 kg/cm

Pr.

Customer:Keltron Controls

2

2

2

o

340 kg/cm 260 C 2

8

2

Qty.

340 kg/cm2 260oC

340 kg/cm2 260oC

Pr.


o

Temp.

360 kg/cm 200 C

Pr.

Customer: Keltron Controls



HP HEATER 5A & B EMERGENCY LEVEL

12

LP HEATER 3 EMERGENCY LEVEL

14


1-HDL-LCV-0757B

1-HDL-LCV-0722

1-HDL-LCV-0768

1-CO-PCV-0530

FCW-PCV-8701

LCV-8701

16

17

18

19

20

21

Tag

ASS-2 TO ASS-7

ASS-20 TO ASS-25

No.

1

2

PRIMARY SCAPH

SECONDARY SCAPH

Service

SCAPH CONTROL VALVES

DM WATER OVERHEAD LEVEL CONTROL

EQUIPMENT COOLING WATER DIFFERENTIAL PR. CONTROL

VALVE GLAND SEALING PRESSURE CONTROL


LP HEATER 1 NORMAL LEVEL


15 1-HDL-LCV-0757A

1-HDL-LCV-0746B


13 1-HDL-LCV-0746A

LCV-0714/0736

HP HEATER 5A & B NORMAL LEVEL

11 1-HDH-LCV-0712/34

LCV-0703/0722

HP HEATER 6A & B EMERGENCY LEVEL

GSC MAIN FLOW

10

LCV-0526

8

CONDENSATE EMERGENCY MAKE-UP

HP HEATER 6A & B NORMAL LEVEL

LCV-0509

7

Service

9 1-HDH-LCV-0701/23

Tag

No.


12 in.

2 in.

8 in.

8 in.

6 in.

6 in.

3 in.

3 in.

4 in.

3 in.

4 in.

3 in.

4 in.

8 in.

Size

300

150

300

300

300

300

300

300

300

600

300

600

600

600

150

Rating*

CF8M

CF8M

WC6

C5

WC6

C5

WC6

C5

WC6

C5

WC6

C5

WC6

WC6

CF8M

Body

35

1660

12

640

640

400

400

155

155

55

60

55

45

55

575

Cv

38-41321

38-41921

Model

4 in.

8 in.

Size

300

300

Rating*

WCC

WCC

Body

200

575

Cv

50 C

110 C 110 C o

90 C o

90 C 60 C

2 2 2 2

50 C 40 C 2

10 kg/cm

46oC

2

2

2

2

2

2

2

2

2

4

4

4

4

2

2

Qty.

20 kg/cm

20 kg/cm

Pr.

250 C o

250 C 2

o

2

Temp.

* ANSI

4

4

Qty.


10 kg/cm2

o

o

2

47 kg/cm

60oC

o

o

3 kg/cm2

3 kg/cm

3 kg/cm

3 kg/cm

4 kg/cm

4 kg/cm

o

190 C 2

34 kg/cm

2

o

34 kg/cm2 190oC

57 kg/cm2 240oC

57 kg/cm2 230oC

47 kg/cm

40 C 2

o

o

Temp. 2

10 kg/cm

Pr.

Customer:Keltron Controls

Project : NTPC Vindhyachal TPS 2x500 MW STPP

37-41621 1.5 in.

37-41521

37-41612

37-41611

37-41511

37-41611

38-41511

37-41611

38-41511

38-78103

38-41512

37-78103

38-41512

37-78103

38-41621

Model

Project : NTPC Talcher TPS 2x500 MW STPP


Capacity 500 MW


MaterialselectionGuidelines StandardisedMaterialsforhighperformance


MATERIAL SELECTION

Correctmaterialselectionisextremelyimportanttoensure properfunctioningandlongevityofControlValvesinPower pressureandtemperatures,designpressurecangoupashigh as360kg/cm2 andtemperaturesupto566oC.TheBodyand Trimmaterialselectionshouldalsotakeintoaccountthe detrimentaleffectsofCavitation/Flashing/HighVelocity whichareinherenttosuchsevereapplications. CONTROL VALVE. PRESSURE CONTAINING MATERIAL General Classification

Castings

Forgings

Max. Operating Temp.

Carbon Steel

ASTM A 216 Gr. WCB / WCC

ASTM A 105

427ºC

Alloy Steel, 1 ¼ Cr - ½ Mo

ASTM A 217 Gr. WC6

ASTM A 182 Gr. F11

566ºC

Alloy Steel, 2 ¼ Cr - 1 Mo

ASTM A 217 Gr. WC9

ASTM A 182 Gr. F22

566ºC

Alloy Steel, 5 Cr - ½ Mo

ASTM A 217 Gr. C5

ASTM A 182 Gr. F5a

566ºC

Stainless Steel, Ty. 316

ASTM A 351 Gr. CF8M

ASTM A 182 Gr. F316

566ºC

PRESSURE RATING. CEILING VALUES * Temp.

150#ANSI

300#ANSI

600#ANSI

900#ANSI 1500#ANSI

2500#ANSI

< 93ºC

18.3

52.7

105.5

158.2

263.7

439.4

149ºC

16.2

51.3

102.3

153.6

255.9

426.8

204ºC

14.1

49.6

99.1

148.7

248.2

413.4

260ºC

12.0

46.8

93.5

140.3

233.8

389.5

316ºC

9.8

42.5

85.1

127.6

212.7

354.4

371ºC

7.7

40.1

79.8

119.9

199.7

332.6

427ºC

5.6

35.9

71.4

107.2

178.6

297.4

482ºC

3.5

31.6

63.3

94.9

157.8

263.3

538ºC

1.4

25.7

51.0

76.6

128.0

213.0

593ºC

0.0

22.9

45.3

67.8

113.2

188.8

2

* Max.. Working Pressure in Kg/cm for ANSI 150# to ANSI 2500#, Extracted from ANSI B16.34 - 1996. Varies with material, See pages 48-50 for max. allowable working pressures for WCC, WC6 & WC9, the most common body material used for Control Valves in power plant applications.

5.1 Body material specs

Plantapplications.Theserviceconditionsvarywidelyin


Allowable working pressure (Kg/cm2)

5.2 Allowable working pressure

Allowable working pressure for ASTM A 216 Gr. WCC

Operating temperature (oC)


Allowable working pressure for ASTM A 217 Gr. WC6







Allowable working pressure for ASTM A 217 Gr. WC9


Bar Stock: ASTM A 479 Ty. 410

Bar Stock: ASTM A 582 Ty. 416

NA

NA

NA

NA

Bar Stock: ASTM A 564 Gr. 630 Castings: ASTM A 747 CB7CU1

Casting: ASTM A743 Gr. CA6NM (HeatTreated)

Bar Stock: ASTM A276 Ty.440C

Ty. 416 Stainless Steel (Hardened&Tempered)

No.6 Stellite Hard Facing

No.6 Stellite Solid (< 2”)

No.5 Colmonoy Hard Facing

No.6 Colmonoy Hard Facing

17.4 PH Stainless Steel

CA6NM Stainless Steel

Ty. 440C Stainless Steel

Bar Stock: ASTM A 479Ty. 316 Castings: ASTM A 351 Gr. CF8M

ASTM CODE

Ty. 410 Stainless Steel (Hardened&Tempered)

TOUGH SERVICE

SS 316

GENERAL SERVICE

400ºC

650ºC

400ºC

650ºC

650ºC

650ºC

650ºC

400ºC

400ºC

593ºC

MAX. TEMP.

58 HRC min.

afterNitriding)

28 HRC min.

40 HRC min (H900) 32 HRC min (H1075)

56-62 HRC

45-50 HRC

38-47 HRC

38-47 HRC

31-38 HRC

35 HRC min.

14 HRC max.

HARDNESS

Very Erosive Service.

Erosive & Corrosive Service. (700-1000 HV After case hardening, excellent for high temperatureservice.

Erosive & Corrosive Service

Erosive & Corrosive Service. Corrosion resistance similar to Inconel

Erosive & Corrosive Service. Corrosion resistance similar to Inconel

Erosive & Corrosive Service

Slightly Erosive & Corrosive Service

Erosive & Non- Corrosive Service

Corrosive & Non- Corrosive Service

Non-Erosive, Corrosive,Mod. Press. Drop. Most corrosion resistant of 300 Series

GENERAL APPLICATION

5.3 Trim material selection

GENERAL CLASSIFICATION.


HandlingandInstallation A list of safe practices


6.1 Handling & Installation

Fig. 24. Clearance requirements for Globe Control Valves

1. Do not lift large size valves by the Actuator. Lifting Lugs providedontheActuatorsare forliftingtheActuatoralone. 2. The Actuator Diaphragm case, Eye Bolts etc. are not designedtolifttheheavy valve body assembly. 3. Do not turn the Actuator, keepingthecouplingtight.

6. While choosing the location to mount the valve, provideadequatespacefor future occasions when it may become necessary to remove theBodyandActuator forrepairs. 7. Ensure that recommended mountingorientationsare alwaysfollowed.

8. Ensure that the Flange 4. In case of Bellow Sealed Valves,neverrotatetheValve Bolts or Tie Rods can be removedeasily. stem. 5. Valves on smaller piping andtubingmayneedtobe mountedinBrackets.

9. Leave adequate space for opening/adjusting Positioners and Accessories.

6.1Handling & Installation


Fig. 25. Alternate orientations for Control Valves (position-1 is preferred)

10. Positioner Gauges and 13. Special attention must be Travel Indicators must always given not to place an elbow remainclearlyvisible. or pipeT less than 5 pipe diameters downstreamofa 11. Careful choice of valvetoavoidinterference locationhelpsprevent withtheValve’sFlow Cavitation. When flow is Capacity. In high pressure gas upward,andifthefluid partiallyvaporizesbecauseof orsteampressurereducing applications, try to have only lowerhydrostatichead, straightpipesdownstreamof locatingtheValvetowards the valve, or alternatively use thelowestpartofthepiping alongsweepingelbowto canpreventtwophaseflow avoidaddedpipenoise. throughtheValvethereby minimizingCavitation. 14. In critical applications, 12. Valves in Flashing service are to be located as close to the receiving vessel as possible. A very short length of Discharge Pipe, and an IsolationValvearepermitted.

provideamanuallyoperated throttling valve in a bypass around the valve. This allows forreplacementorrepairof theControlValvewithout shutting down the process.


Fig. 27. Less satisfactory arrangement of upstream and downstream piping

15. Since Control Valves will require maintenance from time to time, Block Valves at Upstream and Downstream are essential. Bleed and drain valves may be necessary for safety. 16. On occassions when the Control Valve is out of service, if a Bypass Valve is being provided along with isolation valves in order to have flow, the style of the Bypass Valve should be similar to that of the Control Valve. Or else an identical Control Valve should be chosen as the Bypass Valve. 17. In cases of extreme ambient temperatures (over 80ºC) where a valve is located, the valve and accessory manufacturersshouldbeconsultedforproper,high temperaturereplacementmaterial.

6.1 Handling & Installation

Fig. 26. Typical satisfactory arrangement of upstream and downstream piping

MaintenanceGuidelines Howtoensurepeakperformance of Control Valves in power plant applications


1. PREVENTIVE MAINTENANCE BEFORE

START-UP

3. Ensure that the recommendedmounting orientationisfollowed.If a valve is mounted with it’s stemtravellinginthe horizontalplane,itmustbe properlysupported.

2.Ensure that misalignment alongthepipelineisnot corrected using the valve. Pipeline stress on the valve maycausemisalignmentof the stem or plug/seat joint. It can also cause flange leak or packingleak.

5. Piping should be flushed before installing the valve. If additionalflushingisdone afterinstallation,itmaybe necessary to remove the internals, Especially if antiCavitation or low noise Trim is inplace.

AFTER

1.Periodicfieldinspections shouldbemade. 2. Rememberthathighfrictionpackingneedstobe compressedafterinsertion. Packingwillcompressfurther inservice,andthepacking compressionmayhavetobe readjusted.Tightenthe packingnutswhenfound necessary. 3. It dusty or dirty conditions prevail,providearubberboot aroundthestemtoprotectthe packing.

4. Ensure that the mandatory ‘flowthrough’direction indicatedontheControl Valve (by an arrow mark) is alwaysfollowed.

Continuedinnextpage START-UP

4. Cover the valve suitably whenprocessdrippingor corrosiveatmospheric conditionsprevail.Specialcare tobegiventothevalve accessories. 5. Airsetsusuallyhavefilters thatcanclog;thedraincock shouldbeopenedfromtimeto timetobesuretrappedliquidis drained. 6. Monitor the performance of the valve accessories as it hasa significanteffecton the valveperformance.

7.1 Prevetive maintenance

1. It should be appreciated thatduringplantstartups, abnormaloperating conditions can adversely affecttheperformanceofthe Control Valve and some times severely damage the valve. It is very important that these abnormalconditionsbe recognizedandtheControl Valveisselectedtakinginto account these conditions.


7.2 Shop overhaul

2. SHOP OVERHAUL 1. Valves and valve internal in hazardousserviceshouldbe cleanedthoroughlybefore undertakinganyrepair. Dependingoncontaminant, waterwash,steamingor specialheattreatmentmay beresortedto. 2. Ensure that the person whoisdisassemblingthe ControlValveisthorough withthereleventprocedure. 3. Before disassembly, mark theActuatororientationwith respect to the body flanges. Maintenance.Beforestartup

6. If line trash like weld chips, rust etc. are expected in the pipeline,temporarystrainers shouldbeinstalledupstream. If the process stream normally contains Scale, dirt orotherforeignmaterial,itis recommendedthat permanentstrainersorfilters beinstalled.Strainersshould beinstalledfarenoughto allownon-swirlflowatthe valve inlet. Note that strainersthatefficiently protectthepumpmaynotbe adequatewhenitcomesto removingdebristhatcan damagethevalveTrim.

4. Remove the bonnet from thebody,andthenthegland packingcomponents. Further removetheTrimand thebottomflange. 5. Disassemble the Actuator andexaminecomponentsfor damage.Afterwardsclean thepartscarefully 6. Inspect the disassembled componentsthoroughlyand determinetheextentof reconditioningandrepair thatisrequired. Continuedinfacingpage CONTINUED FROM PREVIOUS PAGE

8. Air lines to be connected to the Control Valves should be blowncleanofoilanddebris beforetheyareattached. 9. Avoid using Teflon® tapes ininstrumentairlines.While Teflon® tapeisanexcellent threadlubricantandsealfor screwed connections, it neverthelesscanbreakoffin small bits if not carefully applied.Andthesebitsoften migratetoorificesin pneumatic accessories and can clog them.

10. Do not start up a Control 7. Ensure that the air supply is Valvewithoutfirstchecking thepackingtightness. clean and devoid of oil.


ShopOverhaul

7. If the body is rusted, descalethebody.While handlingthebody, theflange surfaces must be protected to preventanygasketleakage.

CONTINUED FROM PREVIOUS PAGE

12. Avoid use of non standard Trims. These cannot matchthemetallurgyand workmanshipoffactory finishedspares.

13. Reassemble the valve bodyusingthereconditioned /new parts. Ensure that gland packingandgasketsare changed every time the valve isopenedandreassembled. Use only OEM* gland packing and gaskets. Low quality gaskets can cause 9. The lapped contact should irreversibledamagetothe not be too wide. If the contact valve by seat area Erosion, bodybonnetErosionetc. band is too wide, a machine cuttorenewtheanglesofthe 14. While tightening the mating pieces is necessary. bonnetandbottomflanges, Theanglesofthemating itisimportanttotightenthe piecesareslightlydifferentto diagonallyoppositeboltsto allowanarrowseatingband. ensureevengasketloading. 10. For problems like marred Over tightening can cause excessive elongation of the stemsurface,replacement with a factory finished stem is gasketstherebyresultingin poorjoints. theonlypracticalsolution. The finish of the Control 15. Assemble parts of the Valve stem is so fine that Actuatorbarrel,installthe highlypolishedsurfacesare diaphragmcaseusingnew requiredtogivethebest cap screws and nuts, and possible packing seal, and to check for pneumatic leaks. minimizethehysteresis. 16. Adjust the spring range 11. If the Trims are beyond andstrokeoftheActuator. repair,replacethemwith 17. Giving air supply to the genuinespareparts.Valve Trimsareamongstthemost Actuator, keeptheActuator precisionofinstrumentation inmidstrokeandmountthe components. Actuatoronthevalvebody. *Original Equipment Manufacturer

7.2 Shop overhaul

8. Assess the need for remachiningofBodyand Trims. First the plug and seat shouldbeperfectlymatched, by precise machining, then by handgrindingorlapping. Make sure that even fine tracesoflappingcompound is cleaned off.


ShopOverhaul

7.2 Shop overhaul

18. Tighten (finger tight) the coupling.Applyairorremove airtoensureproperseatingof the valve. Then tighten the couplingandadjustthetravel indicator.

CONTINUED FROM PREVIOUS PAGE

21. Carry out hydrotest, seat leakagetestandcalibration as per relevant standards.

22. When repair to an existing valve is uneconomical,replaceitwith a new valve from a high19. Mount the accessories back on to the Control Valve. quality OEM to avail of better sizing,bettermaterials, Several of the most common betterdesign,andmostlikely, accessories (Air Sets, better service too. Process Positioners, Transducers etc.) conditionsshouldbe haveRubberDiaphragms stabilizedanddetermined thatwillhardenandcrack. accurately in case they were Some have O Rings that notcorrectlyanticipated deteriorate.Itwouldbe whentheoriginalvalve economicaltoreplacethe was specified. whole accessory with spares 23. Do not buy valves or (andrepairfaultymodels replacementpartsfrom duringslacktime)ratherthan non OEMs. Overemphasis repairing them On Site. on short-term cost savings 20. Tubing connections for cansometimesleadto signalandoperatingair hazardousworking shouldbecheckedwith environmentsforpersonnel, processdowntimeand soapywaterorotherleak increased operating costs. detectingfluids.

TheMILRange HighperformanceControlValvesfor powerplants


MIL 21000 Rugged,heavytopGuided,single seatedControlValves

For severe service, special double stagevalveswithsimultaneous throttlingintheplugandCage alsoisavailable.

Quick Change Trim. Optional clampedseatringfacilitateseasy Trimremoval. Angle Body (70000 Series). Optionalanglebodydesignwith Venturiseatisideallysuitedfor specialapplicationslikeFlashing liquidsandotherchokedflow conditions.

Available Sizes & Rating ½” to 2” 2”: ANSI 150# to ANSI 2500# 3” to 1 0” 0”: ANSI 150# to ANSI 600# SeatleakageclassasperANSI/FCI70.2 Standard:ClassIV. Optional:ClassV&ClassVI FEATURES

Heavy Top Guiding.The Valve plugshankisGuidedwithinthe lowerportionofthebonnet and thisheavyandruggedguiding ensuresplugstabilityand eliminatesTrimvibration. AntiCavitation/Low Noise Trims replacingconventionalplug with theLo-dBplugprovidesexcellent noiseattenuationandCavitation control.

8.1 MIL 21000 Series

Tight Shut-Off: Class IV leakage isstandard.Optional constructions meet Class V & Class IV leakage.


MIL 41000 HeavyDutyCageGuided ControlValves.

Standardisedhighperformance material. Thisensurestrouble freeoperationevenin applicationswithinherenthigh pressuredropsandextreme temperatures.


Tight shut off valves. For lower sizes,unbalanceddesignresults in Class V leakage. Forhighersizes,theexceptional singleseatedleaktightnessof Class V is achieved by the followingspecialoptions: 1.Auxiliaryshut-offpilotplug closesthebalancingholeslocated inthemainpluginshut-off conditions.

Available Sizes & Rating ¾” to 14”: ANSI 1 50# to ANSI 2500# 20”: ANSI 150# to ANSI 600# 16” to 20” SeatLeakageClassasperANSI/FCI70.2 Standard:ClassIII&ClassIV Optional:ClassV FEATURES

High allowable pressure drops. Cage Guided valves provide exceptionalperformanceovera widerangeofpressuredropsin severe services. They also handle mostshutoffpressureswith standardpneumaticspring diaphragmActuators. High capacity with low pressure recovery.Flowcapacitiesremain attoplevels,andareattained withminimumpressurerecovery reducingthepossibilityof Cavitationinliquidservice.

2.Selfenergisedsealrings pressingagainstwallsoftheCage &Plugarrestsleakagepastthe sealring. Lo-dB/Anti-Cavitation Cages: NoiseattenuationandCavitation controlachievedbyreplacing conventional Cages with Lo-dB Cages. SPECIAL

OPTIONS

Static Seal Ring, Double Cage design, Two stage design with diffuser seat ring, Multi-Stage Valves MIL 41008 . These Multi-Stage valves incorporateauniqueTrimdesignto absorb high pressure drops that prevent Cavitation and maintain constantvelocitythroughoutthe pressure dropping stages. Concentric Cages incorporate a tortuous flow path, which causes numerous velocity head losses withoutappreciablepressurerecovery. High pressure recovery factors at lower lifts eliminates Cavitation. High impedance flow path reduces pressure by friction and turbulence, maintaining constant velocity throughout.


MIL 78000 AntiCavitation&LowNoise Multi-stepHighPressureDrop ControlValves

High Noise Levels commonly associatedwithconventionally designedControlValves. High allowable pressure drops. Noindividualstageisexposedto thefullpressuredrop,thus extendingTrimlifesubstantially.

Low pressure recovery. This minimisesCavitationpotential andcontributestowards reductionofNoiseforallfluids. Pressure recovery factors as high as 0.998.

Available Sizes & Rating ½” to 6” 6”: ANSI 900# to ANSI 2500# SeatleakageClassasperANSIIFCI70.2 Standard:ClassV Optional:ClassVI FEATURES

Multi Step Axial Flow High Resistance Trim. Pressure reductionoccursalongthelength ofthepluginaseriesofthrottling stages. The fluid also takes a tortuousflowpath,whichadds resistanceandthereforevelocity headloss. Thespecialdesignprovides controlofhighpressurefluids withouttheErosion,Vibrationor

Standardisedhighperformance material:Toensurematerial integrity, 78000 Series valves are machinedfromsolidsteel forging.HighperformanceTrim materialensuresdurabilityinany severeapplication. Balanced Trims: Availablefor sizes 2" and above, allow much highershut-offpressureswith conventionalActuators. SPECIAL

OPTIONS.

Soft seat construction with encapsulated inserts, Angle & Inline bodyconfigurations.


Adiabatic Flow with Friction Friction. Reducespressuremuchinthe same way as pressure loss occurringinalongpipeline.


MIL 91000

MATRIX Series valves


ExtremePressureMulti-stage,Multi-path,AxialFlowAnti-Cavitation HighPressureDropControlValves

FEATURES.

Varyingandexpandingflow passage. This enables near Zero Pressure Recovery thus ensuring thatstagewisePressureDropsare limitedbelowtheCriticalPressure Drop.LikelihoodofCavitationis ruledouteveninextreme conditions. Ingenious Flow Path. Reduces downstreamVelocity.Exit VelocityandKineticEnergykept underlimits.Erosioneliminated. Pressure recovery factor (Cf) as high as 0.9999.

Flow to Open flow direction. Eliminates DynamicInstability inherent to Flow to Close valves. TortuousflowpathwithHigh Impedance forenergy absorption limits Trim Velocity Velocity. Modified equal % characteristics with 100 : 1 Rangeability. Characteristics can be customised to suit specific process applications. Self energised body and seat gaskets gaskets. Ensures Zero Leak, and optimisesbonnet/boltingdesign.

Ingenious design. Results in a As many as 50 Pressure Dropping simplermanufacturingprocess. stages. Consequentlythismakes MATRIXSeries Valvesbetter Ruggedness of design. Ensures pricedthanothervalvesinthis longevityevenintheseverestof league. applications. Axial Flow design. Eliminates wiredrawingeffectsonthe leadingedgesoftheplug.

SPECIAL

OPTIONS.

Available with Soft Seat with a special sliding collar to protect the Soft Seat from high pressure fluids.

MIListhefirstControlValvemanufacturerinIndiatohavebeenawardedtheprestigiousCEMarkingCertificatebyRWTUV,Germany.


INDEX A

9.1 Index & List of Illustrations

Allowable working pressure 48

B Block Valve 24 Body Material Specs 47 Boiler Feed Pump Min. Recirculation Valve 13, 17, 18 Boiler Feed Pump Minimum Recirculation System 17 Boiler Feed Water Startup Valve 13, 17 Boiler Main Feed Water Control Valve 13, 17

C CE Marking 8, 71 Company overview 8 Condensate Recirculation Valve 13, 14 Condensate system 13, 14 Condenser 14

D Deaerator 14, 15, 17 Deaerator Level Control Valve 13, 14, 15, 16 Deaerator Pegging Steam System 26 Deaerator Pegging Steam Valve 13, 22, 26, 27

E Economisers 17

F Feed Pump Recirculation 18 Feed Water Control 20 Feed Water Heaters 31 Feed Water Pumps 17 Feed Water Regulating System 20 Feed Water Regulator Valve 20 Feed Water System 13, 17 Foster Wheeler 8 Full Load Feed Water valve 20

G General Boiler Flow Diagram 10

H Handling and Installation 53 Heater Drain System 13, 31 Heater Drain Valve 31 High pressure heater drain valves. 13 HP Heaters 31 HP Heaters System 32, 55

L Low Load Feed Water valve 20 Low pressure heater drain valves. 13 LP heaters 31 LP Heaters System 32

M Main Steam Line 22 Main Steam Pressure Reducing Valve 22, 29, 30 Main Steam System 13, 22 Maintenance Guidelines 59 Martensitic Steel 15 Material Selection Guidelines 45, 47 MATRIX Series 8, 19, 70 MIL 21000 31, 67 MIL 41000 16, 21, 27, 31, 68 MIL 41003 27 MIL 41008 15, 21, 25 MIL 41100 23, 24 MIL 41114 28 MIL 41121 30 MIL 41128 25 MIL 41200 23, 24 MIL 41221 30 MIL 41400 24 MIL 41621 16 MIL 41912 30 MIL 41914 30 MIL 41921 16 MIL 70000 67 MIL 71114 28 MIL 78000 15, 18, 19, 25, 69 MIL 91000 19, 70 MIL Controls Limited 6, 8 Modulating Type System 18

O On/Off System 18 Original Equipment Manufacturer 63

P Positioner Gauges 56 PRDS Spray Control Valves 22 PRDS Station Valves 29 PRDS System Control Valves 22 PRDS System Valves 13 Pressure Reducing Desuperheating System 29 Preventive Maintenance 61

R Reheater Attemperator Control Valve 25 Reheater Attemperator Spray Valve 13 Reheater Spray Block Valves 22 Reheater Spray Control Valves 22 Reheater System 22 Remachining 63 RWTUV 71

S Shop Overhaul 62 Sliding Collar Seat Ring 19 Soot Blower 24, 27 Soot Blower Pressure Control Valves 22 Soot Blower Steam Pressure Reducing Valves. 13 Soot Blower Valve 27 Soot Blowing System 22 Soot Blowing Valves 27 Steam Ejectors 29 Steam Soot Blowers 27 Strainers 62 Super Heater Attemperator Valve 22, 23 Superheater Attemperator Block Valve 22, 24 Superheater Attemperator Spray Valve 13 Superheater Spray Control Valves 22 Superheater System 22

T Teflon® tapes 62 Temperature Control Valve(Spray water) 29 Trim material selection 51 Turbine Bypass Valves. 13 Typical Applications 116 MW 37 Typical Applications 210 MW 39 Typical Applications. 250 MW 41 Typical Applications. 500 MW 43 Typical Applications. 67.5 MW 35

U Upstream Piping 57

ILLUSTRATIONS Fig. 1. GeneralBoiler(Drumstyle)FlowDiagram 10 Fig. 2. CondensateSystem 14 Fig. 3. MIL 78000 15 Fig. 4. MIL 41000 16 Fig. 5. BoilerFeedPumpMin.RecirculationSystem 17 Fig. 6. MIL78000.FeedpumpMin.RecirculationValve 18 Fig. 7. MIL 91000 19 Fig. 8. FeedWaterRegulatingSystem. 20 Fig. 9. MIL 41008. Multi stage, Low Load Valve21 Fig. 10. CriticalControlValvesinMainSteamLine 22 Fig. 11. MIL41100.SuperheaterAttemperatorvalve 23 Fig. 12. MIL41200.SuperheaterAttemperatorvalve 23 Fig. 13. MIL41400.SuperheaterAttemperatorblock 24 Fig. 14. MIL78000.ReheaterAttemperatorControl 25 Fig. 15. MIL41008.ReheaterAttemperatorControl 25 Fig. 16. DeaeratorPeggingSteamSystem 26 Fig. 17. MIL 41003 27 Fig. 18. MIL 71114 28 Fig. 19. TypicalAuxiliaryPRDSSystem 29 Fig. 20. MIL 41914 30 Fig. 21. MIL 21000 31 Fig. 22. LP Heaters System 32 Fig. 23. HP Heaters System 32 Fig. 24. ClearancerequirementsforValves 55 Fig. 25. AlternateorientationsforControlValves 56 Fig. 26. Typicalsatisfactorypiping57 Fig. 27. Lesssatisfactoryarrangementofpiping57

MIL Controls Limited

Control Valves for Power Plants. ApplicationHandbook TheMILPowerPlantHandbookprovides a broad overview of the various systems in a Thermal Power Plant to help you selecttherightvalveforeachapplication. The handbook also offers expert tips for proper Installation and Maintenance of your Control valves. Registered Office & Works. Meladoor , Mala, PIN 680 741, Thrissur District, Kerala, India. Tel: + 91 (0)488 890272, 890772, 891773. Fax: + 91 (0)488 890952. Email: [email protected] Marketing Head Office. P. B. No. 04, Aluva, PIN 683 101, Ernakulam Dist, Kerala, India. Tel: + 91 (0)484-624955, 624876, 628041. Fax: + 91 (0)484-623331. Email: [email protected]

© MIL CONTROLS LIMITED, 2002. All rights reserved

HB/Power/Rev-A/03·2002

A KSB Company

Power Plant Handbook

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