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
CONTROL VALVES FOR POWER PLANTS
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.
APPLICATION HANDBOOK
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.
APPLICATION HANDBOOK
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
3.2 Condensate system
CONTROL VALVES FOR POWER PLANTS
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.
APPLICATION HANDBOOK
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.
3.2 Condensate system
TheDeaeratorisanopencontact typeFeedWaterHeaterwhich purgesanynoncondensableand dissolved gases. Also the Deaeratoractsas areservoirfor FeedWatertosmoothentheFeed Watersupplyatvaryingloads.
3.2 Condensate system
CONTROL VALVES FOR POWER PLANTS
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.
APPLICATION HANDBOOK
~
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.
CONTROL VALVES FOR POWER PLANTS
3.3 Feed Water 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.
APPLICATION HANDBOOK
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.
CONTROL VALVES FOR POWER PLANTS
3.3 Feed Water system
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
APPLICATION HANDBOOK
3.3 Feed Water system
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
CONTROL VALVES FOR POWER PLANTS
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.
APPLICATION HANDBOOK
Fig. 12. MIL 41200. Superheater Attemperator valve.
3.4 Main steam system
Fig. 11. MIL 41100. Superheater Attemperator valve.
CONTROL VALVES FOR POWER PLANTS
3.4 Main steam system
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.
APPLICATION HANDBOOK
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.
3.4 Main steam system
Fig. 14. MIL 78000. Reheater Attemperator Control Valve.
3.4 Main steam system
CONTROL VALVES FOR POWER PLANTS
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
APPLICATION HANDBOOK
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
3.4 Main steam system
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.
3.4 Main steam system
CONTROL VALVES FOR POWER PLANTS
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)
APPLICATION HANDBOOK
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
3.4 Main steam system
Fig. 19. Typical Auxiliary PRDS System
3.4 Main steam system
CONTROL VALVES FOR POWER PLANTS
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.
APPLICATION HANDBOOK
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
CONTROL VALVES FOR POWER PLANTS
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
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
Project: TISCO 1X67.5MW
90-41921 6x3 in.
38-41921 6x3 in.
38-78101
Model
Project: TISCO 1X67.5MW
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.
0
1
1
1
Qty.
0
0
4
2
4
2
0
0
2
0
185 kg/cm 150 C
2
185 kg/cm 150 C
2
185 kg/cm 175 C
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
2
186 kg/cm 242 C
2
110 kg/cm 350 C
0
185 kg/cm 250 C 2
2
4
185 kg/cm 250 C 0
Qty. 2
Temp.
Pr.
Customer: BHEL Trichy
2
170 kg/cm 235 C
0
170 kg/cm 235 C 2
170 kg/cm2 2350C
Pr.
Customer: BHEL Madras
4.1 Typical applications. 67.5 MW
Capacity 67.5 MW
APPLICATION HANDBOOK
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
Project: Ahemedabad Electricity Company.
38-78001
37-41612
38-41621
Model
Project: Ahemedabad Electricity Company.
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.
Customer:BHEL Bangalore
2
2
121 C
15 kg/cm
0
Qty.
2
Temp.
Pr.
Customer: BHEL Bangalore
4.2 Typical applications. 116 MW
CONTROL VALVES FOR POWER PLANTS
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
Project: Ahemedabad Electricity Company.
37-211X5
37-78003 1.5 in.
Model
Project: Ahemedabad Electricity Company.
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.
Customer:BHEL Bangalore
2
o
Temp.
115 kg/cm 122 C
Pr.
Customer: BHEL Bangalore
4.2 Typical applications. 116 MW
Capacity 116 MW
APPLICATION HANDBOOK
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
SOOT BLOWER STEAM PR.REDUCING VALVE
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
WC9
WC9
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
15
0.3
2.4
6
50
Cv
25
3.6
40
60
3.8
60
30
195
Cv
45
575
Cv 2
2
Qty.
2 8 2
265 kg/cm 260 C 265 kg/cm 260 C 265 kg/cm2 260oC
8 4
185 kg/cm 440 C o
Temp.
1
286 kg/cm 250 C
* ANSI
1
286 kg/cm2 250oC o
1
286 kg/cm2 250oC
2
1
1
Qty.
165 kg/cm2 540oC
165 kg/cm2 540oC
Pr.
Customer:BHEL Madras
2
o
265 kg/cm 260 C 2
8
o
o
265 kg/cm2 260oC
2
2
o
8
Qty.
265 kg/cm 260 C 2
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
4.3 Typical applications. 210 MW
CONTROL VALVES FOR POWER PLANTS
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 DEAERATOR
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.
10 in.
6 in.
Size
3 in.
2 in.
1 in.
6 in.
38-41621 1.5 in.
37-41611
37-41611
37-211X5
37-78003
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
300
300
300
300
300
300
300
300
300
300
300
300
300
300
600
600
600
600
300
Rating*
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
o
180 C 180 C 130 C 130 C 100oC
2 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
o
8 kg/cm2
8 kg/cm
8 kg/cm
8 kg/cm
20 kg/cm
20 kg/cm
o
2
48 kg/cm2 215oC
48 kg/cm2 215oC
48 kg/cm
48 kg/cm
o
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Qty. o
Temp. 2
20 kg/cm
Pr.
Customer:BHEL Delhi
o
Temp.
260 kg/cm 250 C
Pr.
Customer: BHEL Hyderabad
4.3 Typical applications. 210 MW
Capacity 210 MW
APPLICATION HANDBOOK
0728.1&2
728.3
1
2
LOW LOAD FEED WATER FLOW CONTROL
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
SOOT BLOWER STEAM PR.REDUCING VALVE
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
SPRAY & SOOT BLOWER VALVES
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
2 8 2 8 8 2
262 kg/cm 350 C 182 kg/cm 350 C 282 kg/cm 350 C 282 kg/cm 350 C 182 kg/cm2 350oC 182 kg/cm2 450oC
o
o
o
o
2 2
267 kg/cm 170 C 2
o
o
267 kg/cm 170 C 2
2
2
267 kg/cm2 170oC 48 kg/cm2 360oC
2
Qty. 2 o
Temp. 169 kg/cm 545 C 2
267 kg/cm2 170oC
Pr.
Customer:BHEL Bangalore
2
2
2
2
o
8
Qty.
182 kg/cm 260 C 2
o
Temp.
2 2
262 kg/cm 260 C
Pr.
Customer:BHEL Trichy
o
2
Qty.
330 kg/cm 248 C 2
o
Temp.
4 2
330 kg/cm 248 C
Pr.
Customer: BHEL Delhi
4.4 Typical applications. 250 MW
CONTROL VALVES FOR POWER PLANTS
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)
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-2 NORMAL DRAIN TO LPH-1
LPH-3 ALT. DRAIN TO LP FLASH TANK
LPH-3 NORMAL DRAIN TO LPH-2
HPH-5 ALT. DRAIN TO HP FLASH TANK
HPH-5 NORMAL DRAIN TO DEAERATOR
HPH-6 ALT. DRAIN TO HP FLASH TANK
HPH-6 ALT. DRAIN TO DEAERATOR
HPH-6 NORMAL DRAIN TO HPH-5
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.
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
3
PEGG. STEAM FROM CRH TO DEAERATOR
150
300
150
300
300
600
300
300
150
150
150
150
300
300
600
600
600
600
CF8M
CF8M
WCC
WCC
WCC
A105
WCC
WCC
WCC
WCC
WCC
WCC
WC6
WC6
WC6
WC6
WC6
WCC
WCC
CRH-2
300
2
8 in.
38-41912
AS-2
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
48 kg/cm
o
360 C 2
48 kg/cm
2
o
14 kg/cm2 220oC
Customer: BHEL Delhi
260 kg/cm2 250oC
Customer: BHEL Hyderabad
4.4 Typical applications. 250 MW
PEGG. STEAM FROM AUX. STEAM HEADER TO DEAERATOR
Project : Kothagudem TPS, 2*250 MW
A105
HEATER DRAIN & CONDENSATE SYSTEM VALVES
2500
37-78103 4x2 in.
1
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
APPLICATION HANDBOOK
FCV-0657
1
LOW LOAD FEED WATER FLOW CONTROL
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
SOOT BLOWER STEAM PR.REDUCING VALVE
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.
HEATER DRAIN & CONDENSATE SYSTEM VALVES
Tag
No.
SPRAY & SOOT BLOWER VALVES
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.
16 in.
12 in.
Size
300
300
300
600
600
300
Rating*
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.
2 8 8 4
340 kg/cm 260 C 340 kg/cm 260 C 340 kg/cm 260 C 213 kg/cm 482 C o
o
o
Qty. 2
295 C 2
4 2 2
47oC 50oC 40 C
47 kg/cm2 2
10 kg/cm
47 kg/cm2
o
* ANSI
2 6
47oC
57 kg/cm
47 kg/cm2
o
410 C
o
Temp. 2
20 kg/cm
Pr.
Customer:Keltron Controls
2
2
2
o
8 2
340 kg/cm2 260oC
Qty. 2
Temp. 340 kg/cm2 260oC
Pr.
Customer:BHEL Trichy
o
Temp.
360 kg/cm 200 C
Pr.
Customer: Keltron Controls
4.5 Typical applications. 500 MW
CONTROL VALVES FOR POWER PLANTS
HP HEATER 5A & B EMERGENCY LEVEL
12
LP HEATER 3 EMERGENCY LEVEL
14
LP HEATER 2 EMERGENCY LEVEL
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 EMERGENCY LEVEL
LP HEATER 1 NORMAL LEVEL
LP HEATER 2 NORMAL LEVEL
15 1-HDL-LCV-0757A
1-HDL-LCV-0746B
LP HEATER 3 NORMAL LEVEL
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.
HEATER DRAIN & CONDENSATE SYSTEM VALVES
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
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
50 C
190 C 110 C 110 C o
90 C o
90 C 60 C
2 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.
250 C
20 kg/cm
o
250 C 2
o
Temp. 2
20 kg/cm
Pr.
* ANSI
4
4
Qty.
Customer:BHEL Trichy
10 kg/cm2
o
o
2
47 kg/cm
60oC
o
o
o
3 kg/cm2
3 kg/cm
3 kg/cm
3 kg/cm
4 kg/cm
4 kg/cm
34 kg/cm
o
2
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
4.5 Typical applications. 500 MW
Capacity 500 MW
APPLICATION HANDBOOK
MaterialselectionGuidelines StandardisedMaterialsforhighperformance
APPLICATION HANDBOOK
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
CONTROL VALVES FOR POWER PLANTS
Allowable working pressure (Kg/cm2)
5.2 Allowable working pressure
Allowable working pressure for ASTM A 216 Gr. WCC
Operating temperature (oC)
APPLICATION HANDBOOK
Allowable working pressure for ASTM A 217 Gr. WC6
5.2 Allowable working pressure
Allowable working pressure (Kg/cm2)
Operating temperature (oC)
CONTROL VALVES FOR POWER PLANTS
Allowable working pressure (Kg/cm2)
5.2 Allowable working pressure
Allowable working pressure for ASTM A 217 Gr. WC9
Operating temperature (oC)
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.
APPLICATION HANDBOOK
HandlingandInstallation A list of safe practices
APPLICATION HANDBOOK
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
CONTROL VALVES FOR POWER PLANTS
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.
APPLICATION HANDBOOK
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
APPLICATION HANDBOOK
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.
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.
2. Rememberthathighfrictionpackingneedstobe compressedafterinsertion. Packingwillcompressfurther inservice,andthepacking compressionmayhavetobe readjusted.Tightenthe packingnutswhenfound necessary.
5. Airsetsusuallyhavefilters thatcanclog;thedraincock shouldbeopenedfromtimeto timetobesuretrappedliquidis drained.
3. It dusty or dirty conditions prevail,providearubberboot aroundthestemtoprotectthe packing.
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.
CONTROL VALVES FOR POWER PLANTS
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.
APPLICATION HANDBOOK
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.
CONTROL VALVES FOR POWER PLANTS
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 Several of the most common sizing,bettermaterials, 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
APPLICATION HANDBOOK
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.
CONTROL VALVES FOR POWER PLANTS
MIL 41000 HeavyDutyCageGuided ControlValves.
Standardisedhighperformance material. Thisensurestrouble freeoperationevenin applicationswithinherenthigh pressuredropsandextreme temperatures.
8.2 MIL 41000 Series
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.
APPLICATION HANDBOOK
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.
8.3 MIL 78000 Series
Adiabatic Flow with Friction Friction. Reducespressuremuchinthe same way as pressure loss occurringinalongpipeline.
CONTROL VALVES FOR POWER PLANTS
MIL 91000
MATRIX Series valves
8.4 MIL 91000 Series
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.
MIListhefirstControlValvemanufacturerinIndiatohavebeenawardedtheprestigiousCEMarkingCertificate byRWTUV,Germany.
CONTROL VALVES FOR POWER PLANTS
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:
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HB/Power/Rev-A/03·2002
A KSB Company
