hysys v8.6

Rev1.0 ‐1‐ February26,2015

SteamCycleSimulation–HYSYSv8.6TheattachedgivesstepstosetupasimulationinHYSYSv8.6tomodelasimpleRankinesteamcycleforelectricityproduction.Thesystemconsistingof:

Fuelgassidewithairblower,combustionchamber,&fuelgassideofthesteamboiler. Steamsidewithsteamturbine,steamcondenser,condensatepump,&steamsideofthe

boiler.Thesimulationwillfirstbesetupassumingisentropicstepsfortherotatingequipment.Itwillthenbemodifiedtoaccountformorerealisticefficiencies(boththermodynamicandmechanical).WhenthesimulationissetuptheoverallPFDshouldlooklikethefollowingfigure.

Createnewsimulationfile

StarttheprogramfromStart,AllPrograms,AspenTech,ProcessModelingV8.6,AspenHYSYS,AspenHYSYSV8.6.WhentheprogramopenschoosetheNewbutton.

Rev1.0 ‐2‐ February26,2015

DefinetheComponents&thePropertyModels

Specifycomponents,fluidpropertypackages,&crudeoilassays

Thefirststepistoaddtwosetsofpurechemicalspeciestorepresent:

Steamasmodeledbypurewater&usingpropertycorrelationsconsistentwiththeASMESteamTables.

Thenaturalgasfuel,air,&combustionexhaustaspurelightcomponentsmodeledbythePeng‐Robinsonequationofstate(EOS).

Let’sdothesteamfirst.WithComponentListshighlightedclickontheAddbutton.Fromthelistofpurecomponentspickwater.We’renowreadytopickthepropertymodel.

Rev1.0 ‐3‐ February26,2015

Thenextstepistopickafluidpropertypackage.FromtheFluidPackagesscreenclicktheAddbutton.ChoosetheASMESteamoptionandmakesureitisassociatedwithComponentList–1.

Nowlet’saddcomponentstomodelthefuelsideofthesystem.GobacktotheComponentListsitem&clickontheAddbuttontocreateComponentList‐2.Weneedcomponentsforthefollowing:

Naturalgas.Fornowlet’smodelthisasapossiblemixtureofmethane,ethane,&propane. Air.Fornowwe’llmodelthisasamixtureofoxygen&nitrogen. Combustiongases.Attheminimumwe’llalsoneedcarbondioxideandwater.However,

we’llalsowanttotakeintoaccountincompletecombustion(formingcarbonmonoxide)aswellasNOxformation(fornowjustasNO,NO2,&N2O).

Fromthelistofpurecomponentspickthefollowingchemicalspecies.Thenextstepistoassociateadifferentfluidpropertypackageforthesecompounds(sincetheASMESteamTablesareonlyappropriateforpurewater).GobacktotheFluidPackagesscreen&clicktheAddbutton.ChoosethePeng‐RobinsonoptionandmakesureitisassociatedwithComponentList–2.

Rev1.0 ‐4‐ February26,2015

Nowisagoodtimetosavethefilebeforewestartsettinguptheprocesssimulation.ClicktheFiletab&thentheSaveAsitem.

Rev1.0 ‐5‐ February26,2015

Setup&SolvetheFlowsheet

WorkingUnits

ActivatetheSimulationoption.Notethatyou’llseeablankflowsheet.WewouldliketoshowthecalculationswithamodifiedsetofSIunits,inparticular:

Temperatureas°C. Pressureasbar(absolute). Massflowaskg/sec. Molarflowaskg.mol/sec. HeatdutyaskJ/sec. PoweraskW.

UndertheHometabclicktheUnitSetsbutton.UndertheAvailableUnitsSetsselectSI.YoucanexaminethelistunderDisplayUnitstodeterminewhatwillbeusedforthedisplayoftheresultsaswellasthedefaultunitsfortheinput.Mostoftheunitsarewhatwedesire,butnotall.Forexample,youcanseethatPressurewillbereportedinkPa,notquitewhatwewant.

Let’screateanewsetofunits&callit“SI‐bar‐sec”.WiththeSIunitshighlightedintheAvailableUnitsSetslistclicktheCopybutton.ChangetheUnitSetNametoSI‐bar‐sec.Let’snowexaminetheDisplayUnitsfortheonesofinterest(Temperature,Pressure,etc.)andmakesurethatareconsistentwithwhatwewant.TochangeweneedonlyclickonthedropdownlistintheUnitscolumn.Forexample,tochangePressurefromkPatobarweonlyneedtochoosetheappropriateoptionfromthelist.WhendoneclicktheOKbutton.

Rev1.0 ‐6‐ February26,2015

SteamCycle

WewillwanttocreateasimpleRankinecyclewiththefollowingprocessconditions: Saturatedsteamproductionat125bar. Finalcondensationto20°C. Steamturbineoperatingatidealreversibleconditions. Condensatepumpoperatingatidealreversibleconditions. Noextrapressuredropthroughheatexchangersorpiping.

Let’splacethefollowingunitsfromtheModelPalettetotheflowsheet1:Heater,Cooler,Expander,&Pump.Ultimatelyitwillbedepictedasfollows.

Let’sdefinethecondensatepumpfirst.Doubleclickonthepumpicon(probablycalledP‐100).ChangethenametoCondensatePump.Specifynewstreamsfortheinlet,Condensate,theoutlet,HP‐Water,&theenergystream,W‐Pump.MakesurethattheBasis‐1fluidpackageischosen.

1IftheModelPaletteisnotvisiblechoosetheViewtab&clickontheModelPalettebutton.

Rev1.0 ‐7‐ February26,2015

Wewanttomakethisanidealreversiblepump.ClickontheParametersoption&changetheAdiabaticEfficiencyto100%.

Wecaninitializethewatercirculatingintheloopfromhere,too.ClickontheWorksheettab&choosetheCompositionoption.Enter1fortheH2OvalueundertheCondensatecolumn.Aninputformwillpopup&allowyoutoverifythatthisrepresentstheMolesFractionsbasis.ClicktheOKbutton.

ClickonConditionssowecanentervaluesfortheCondensateenteringthepump.SpecifytheTemperatureas20°CandtheVapourfractionas0(i.e.,asaturatedliquid).Let’suseaflowbasisof1kg/s.NoticethatCondensatestreamisfullydefined&otherassociatedvaluesarecalculated(suchasthepressure,molarflow,heatflow,etc.)

Nowlet’sdefinethesteamsideoftheboiler.Doubleclickontheheatericon(probablycalledE‐100).ChangethenametoSteamBoiler.Pulldownthelistfortheinputstream&chooseHP‐Water.Specifynewstreamsfortheoutlet,HP‐Steam,&theenergystream,Q‐Boiler.MakesurethattheBasis‐1fluidpackageischosen.

Rev1.0 ‐8‐ February26,2015

Wewanttoassumeanegligiblepressuredropthroughthisexchanger.ClickontheParametersoption&changetheDeltaPto0.

Nowlet’sspecifytheconditionsforthehighpressuresteam.ClickontheWorksheettab&theConditionsoption.SpecifythePressureas125barandtheVapourfractionas1(i.e.,asaturatedvapor).NoticethatafterenteringthepressuretherestoftheconditionsfortheHP‐Waterstreamarecalculated(sincewenowknowtheoutletpressureofthepump,too).AfterenteringthevaporfractiontherestoftheconditionscanbecalculatedfortheoutletHP‐Steam&therequireddutyQ‐Boiler.Nowlet’sdefinethesteamturbine.Doubleclickontheexpandericon(probablycalledK‐100).ChangethenametoSteamTurbine.Pulldownthelistfortheinputstream&chooseHP‐Steam.Specifynewstreamsfortheoutlet,TurbineExhaust,&theenergystream,W‐SteamTurbine.MakesurethattheBasis‐1fluidpackageischosen.

Rev1.0 ‐9‐ February26,2015

Wewanttomakethisanidealreversibleexpander.ClickontheParametersoption&changetheAdiabaticEfficiencyto100%.

Donotapplyanyotherconditionsatthistime.Nowlet’sdefinethecondenser.Doubleclickonthecoolericon(probablycalledE‐101).ChangethenametoSteamCondenser.Pulldownthelistfortheinputstream&chooseTurbineExhaust.Pulldownthelistfortheoutletstream&chooseCondensate.Specifyanewenergystream,Q‐Condenser.MakesurethattheBasis‐1fluidpackageischosen.

Wewanttoassumeanegligiblepressuredropthroughthisexchanger.ClickontheParametersoption&changetheDeltaPto0.

Nowallunits&streamsshouldbefullycalculated.Therearevariouswaystoviewtheresults.OnewayistoclickontheWorkbookitem.UndertheMaterialStreamstabwecanseetemperatures,pressures,&phaseconditions(i.e.,vaporfractions).UndertheEnergyStreamstabwecanseethecalculatedexchangerduties&rotatingequipmentpowers.

Rev1.0 ‐10‐ February26,2015

Wecanalsoviewthisbasicinformationdirectlyontheflowsheet.Rightclickthevariousstreams&choosetheShowTableoption.Thiscanbedoneforallofthestreamsofinterest.(Thetableswillprobablyhavetobemovedaroundtomaketheresultsreadable.)Bydefaultthematerialstreamtablesshowthetemperature,pressure,&overallmolarflow.Toaddvaporfractiondouble‐clickonthetable,clickAddVariable,chooseVapourFraction,clickOK,&closethePFDTableform.

Rev1.0 ‐11‐ February26,2015

Thereisathirdoptionthatwouldallowyoutocalculatethethermalefficiencyofthesteamcycleaswellassummarizetheresults–addaSpreadsheettothesimulation.FromtheModelPaletteaddaSpreadsheet;doubleclicktoopen.ChangethenametoSteamCycleSummary.ClickontheParameterstabandchangetheNumberofColumnstoatleast5andtheNumberofRowstoatleast11.ClickontheSpreadsheettab&setuptextfieldsthatlooklikethefigureontheright.

Rev1.0 ‐12‐ February26,2015

WenowwanttoassociatemanyofthecelllocationstoresultscalculatedbyHYSYS.Forexample,right‐clickoncellB2&chooseImportVariable;chooseCondensate,Temperature,&thenclickOK.Notethatthetemperatureof20.00Cappearsinthetable;alsonotethatitisformattedasboldblue,meaningthatthisisauser‐inputvalue.(Italsodenotesthatitcanbechangedfromhere,butmoreofthatlater.).Whenallvariablesareassociatedwiththeappropriatecellsthespreadsheetshouldlookasfollows.

Nowlet’saddacouplecalculations.

ThenetpowerproducedwillbethatfromtheSteamTurbineminusthatneededbytheCondensatePump.IncellD10entertheformula“=D8‐D9”.

Wealsowouldtodirectlycalculatethethermalefficiencyofthesteamcycle,i.e.,theratioofthenetpowerproducedbytheheatinfromtheboiler.IncellD11entertheformula“=100*D10/B8”.

Rev1.0 ‐13‐ February26,2015

Nowwehaveasummarytablethatwillshowinasingleplacematerialstreamresults,energystreamresults,unitoperationparameters,&calculatedresults.Forexample,wecanseethatthiscombinationofconditionswillresultinasteamcyclewitha41.25%thermalefficiency.

Notethatthisisalsoa“live”table.Wecanchangeparametershere&theothervalueswillautomaticallyrecalculate.Forexample,ifweweretochangetheSteamTurbine&CondensatePumpadiabaticefficienciesto85%,thenallvalueswouldberecalculatedandwecouldseethatthethermalefficiencydropsto34.94%.

Fuel&CombustionSystem

Wewillwanttocreateasimplenaturalgasburner/boilerwiththefollowingprocessconditions: Naturalgasisavailableatindustrialdeliverypressure,20bar‐g&15°C.Wewill

characterizethenaturalgasas100%methane. Airisavailableat25°C.Wewillcharacterizetheairasa21/79O2/N2molarmixtureand

bonedry(i.e.,nowater).Wewanttoaddenoughairsothatthereis20%excessoxygenbasedoncompletecombustionofthenaturalgas.

Thecombustionprocessoccursnearsatmosphericconditionssothenaturalgasmustbeletdowninpressure.However,ablowerisneededtopushtheairintothecombustionchamber.

Thepressuredropthroughtheburner/boiler/fluecombinationis0.3bar.

Rev1.0 ‐14‐ February26,2015

Thefluegasisexhaustedtotheatmosphereat120°C,atemperaturehighenoughtopreventanyliquiddropout&subsequentcorrosionproblems.

Let’splacethefollowingunitsfromtheModelPalettetotheflowsheet:Valve,Compressor,GibbsReactor2,&Cooler.Ultimatelyitwillbedepictedasfollows.(We’lldiscusstheSpreadsheet,Set,&Adjustoperationsaswego.)

Let’sdefinethenaturalgas&let‐downvalvefirst.Doubleclickonthevalveicon(probablycalledVLV‐100).ChangethenametoGasLet‐DownValve.Specifynewstreamsfortheinlet,FuelGas,&theoutlet,LP‐Fuel.MakesurethattheBasis‐2fluidpackageischosen.

2NotethatreactormodelsareundertheColumnstaboftheModelPalette.

Rev1.0 ‐15‐ February26,2015

Wewillinitializethenaturalgasfromhere.ClickontheWorksheettab&choosetheCompositionoption.Enter1fortheMethanevalueundertheFuelGascolumn.Aninputformwillpopup&allowyoutoverifythatthisrepresentstheMolesFractionsbasis.ClicktheNormalizebuttontosettheothercompositionsaszero.ClicktheOKbutton.

ClickonConditionssowecanentervaluesfortheFuelGasenteringthepump.SpecifytheTemperatureas15°CandthePressureas20bar‐g(notethatthepressuregetsautomaticallyadjustedtoanabsolutebasis).Let’suseaflowbasisof1kg.mol/s.Let’sspecifytheoutletpressureof0.3bar‐gintheLP‐Fuelcolumn(notethatthepressuregetsautomaticallyadjustedtoanabsolutebasis).

NoticethatboththeFuelGas&LP‐Fuelstreamsarefullydefined&otherassociatedvaluesarecalculated(suchasthemassflow,heatflow,etc.)

Rev1.0 ‐16‐ February26,2015

Nowlet’sdefinetheair&theairblower.Doubleclickonthecompressoricon(probablycalledK‐100).ChangethenametoAirBlower.Specifynewstreamsfortheinputstream,Air,theoutlet,Air‐2,&theenergystream,W‐AirBlower.MakesurethattheBasis‐2fluidpackageischosen.

Wewanttomakethisanidealreversiblecompressor.ClickontheParametersoption&changetheAdiabaticEfficiencyto100%.

Rev1.0 ‐17‐ February26,2015

Wewillinitializetheairstreamfromhere.ClickontheWorksheettab&choosetheCompositionoption.Enter0.21fortheOxygenvalueundertheAircolumn.Aninputformwillpopup&allowyoutoverifythatthisrepresentstheMolesFractionsbasis&finishenteringtherestofthevalues.Enter0.79fortheNitrogenvalue.ClicktheNormalizebuttontosettheothercompositionsaszero.ClicktheOKbutton.

ClickonConditionssowecanentervaluesfortheAirenteringthepump.SpecifytheTemperatureas25°CandthePressureas0bar‐g(notethatthepressuregetsautomaticallyadjustedtoanabsolutebasis).Asastartingpointlet’sdefinetheflowrateas12kg.mol/hr.Finally,let’sspecifytheoutletpressureforAir‐2as0.3bar‐gtomatchthatofthefuelgasafterthelet‐downvalve.NoticethatboththeAir&Air‐2streamsarefullydefined&otherassociatedvaluesarecalculated(suchasthemassflow,heatflow,etc.)Nowit’stimetomodelthecombustionportionofthefuelgasburner.Therearevariousoptionsfordoingthis.Oneofthesimplest(andwouldnormallybedoneforhandcalculations)wouldbetodefineallcombustionreactions&specifytheextentofconversionforeach.Instead,we’regoingtotakeadvantageofthefullthermodynamiccapabilitiesofHYSYS&useareactorthatwillminimizetheGibb’sfreeenergy.Allwehavetodoislisttheexpectedproducts&HYSYSwillcalculatetheresultingproductdistributionthathonorsthematerial&energybalancesaswellasanychemicalequilibriumlimitations.

Rev1.0 ‐18‐ February26,2015

DoubleclickontheGibbsReactoricon(probablycalledGBR‐100).ChangethenametoCombustion.SelecttheexistingLP‐Fuel&Air‐2streamsasinlets.Specifynewstreams,CombustionGas,asthevapouroutlet&CombustionLiquidsastheliquidoutlet.MakesurethattheBasis‐2fluidpackageischosen.

That’sprettymuchit.Thedefaultsarezeropressuredrop&includeallspeciesinthecomponentlistaspotentialproduct.WecanexaminetheresultsbyclickingontheWorksheettab.SelectingConditionsshowsthatthereisonlyagasproducedatatemperatureof1731°C.WecanthenlookattheresultingcompositionbyselectingComposition.Theresultsare,bydefault,shownasmolefractions.Notethatallofthemethanehasbeenconsumed.ThereisasmallamountofCOformed(asincompletecombustion)butsomeNOxhasalsobeencreatedfromtheN2intheair.

Nowlet’sseehowmuchheatcanbetransferredoutofthecombustiongases.

Rev1.0 ‐19‐ February26,2015

Nowlet’sspecifythecombustiongassideoftheboiler.Doubleclickontheheatericon(probablycalledE‐100).ChangethenametoHRSG.Pulldownthelistfortheinputstream&chooseCombustionGas.Specifynewstreamsfortheoutlet,FlueGa,&theenergystream,Q‐HRSG..MakesurethattheBasis‐2fluidpackageischosen.Wewillnotspecifyapressuredropacrosstheexchanger.Rather,we’llspecifythepressureoutthestack.ClickontheWorksheettab&theConditionsoption.SpecifythePressureas0bar‐gandtheTemperatureas120°C.Nowtheconditionsfortheinlet&outletstreamscanbedeterminedaswellasthedutyavailable(asQ‐HRSG).Therearestillacoupleitemstobedoneto“cleanup”thesimulation.Thefirstisforamatterofconvenience–howshouldwespecifythepressureoftheAir‐2streamoutoftheblower?RightnowthepressureintotheCombustionoperationissetseparatelyforthetwoinletstreams(LP‐Fuel&Air‐2).Ifastudywastobeperformed&thepressureweretochangethenhavingthespecificationsintwoseparatelocationscouldleadtothembeingchangeddifferently.Itsurewouldbenicetosetitonlyinonelocation&thenhavetheotherlocationupdateautomatically.WecandothiswithaSetoperation.FromtheModelPaletteplaceaSetoperationontheflowsheet.Double‐clickonit(probablycalledSET‐1).RenameasSetBlowerOutlet.DefinetheTargetVariableasthepressureoftheAir‐2stream.We’llusetheSourceasthevaluefromLP‐Fuel.OncethisisimplementedanychangesmadetothepressureofLP‐Fuelwillbeautomaticallytransmittedtotheoutletpressureoftheairblower.

Rev1.0 ‐20‐ February26,2015

Thesecondchangeinvolvesaconvenientwaytomakesurethatthecorrectamountofairisaddedtomatchthe“excessoxygen”spec.Theamountofstoichiometricoxygenisdeterminedfromthecombustionreactions.Formethane,ethane,&propanethereactionsare,respectively: CH4+2O2CO2+2H2O C2H6+3.5O22CO2+3H2O C3H8+5O23CO2+4H2OThisshowsthatweneedtoknowthecompositionofthefuelgas(inmolaramounts)todeterminethestoichiometricamountofoxygenneeded.The“excess”partisadditionaloxygen(asamultiplier)thatisadded.ThefinalconsiderationisthatthespecificationinHYSYSisnotjustfortherateofoxygenbutratheroftheair;sowehavetotakeintoaccountthecompositionoftheairaccountforthelargeamountofnitrogenalsobeintroducedintotheCombustionoperation.Sincewehavesetthecompositionofthefuelgastobepuremethane&thebasisflowrateto1kg.mol/secthenthestoichiometricoxygenflowrateistwicethis,2kg.mol/sec.Wealsoneedtoincreasethisby20%toincludethedesiredexcess.Andweneedtotakeintoaccounttheoxygencontentintheairtodeterminetheairrate.Sooverall:

2

2

O

air

O

1 2 1 0.211.43kg.mol/sec

0.21

excessstoichn f

ny

.

WecoulddothesecalculationspriortorunningHYSYSandentertheairrate.OrwecoulddothecalculationswithinHYSYS.FromtheModelPaletteaddaSpreadsheet;doubleclicktoopen(probablycalledSPRDSHT‐1).ChangethenametoAirRateCalc.Usethedefaultnumberofrows&columns.ClickontheSpreadsheettab&setuptextfieldsthatlooklikethefigureontheright.

Rev1.0 ‐21‐ February26,2015

WenowwanttoassociatemanyofthecelllocationstoresultscalculatedbyHYSYS.Forexample,right‐clickoncellD3&chooseImportVariable;chooseAir,MastComponentMoleFrac,Oxygen,&thenclickOK.Let’sassociateallofthedesiredmolarflowrates.Forexample,forthefuel,right‐clickoncellB4&chooseImportVariable;chooseFuelGas,MolarFlow,&thenclickOK.AssociatethemolarflowfortheairtothecellD7.

Nowlet’saddthefollowingcalculations:

cellD4,“=(B2*2+B3*3.5+B4*5)*B5” cellD4,“=D4*(1+D2)” cellD4,“=D5/D3” cellD4,“=D7‐D6”

Rev1.0 ‐22‐ February26,2015

Nowwehaveatablethatwillcalculatethedesiredairflowrateforthespecifiedfuelgasflowrate.ThoughthespreadsheetcannotdirectlysettheairflowratewecandoitmanuallybydirectlychangingthevalueincellD7.

EventhoughthespreadsheetitselfcannotdirectlysettheflowrateoftheAirstreamitcanbeusedaspartofanAdjustoperation.FromtheModelPaletteplaceanAdjustoperationontheflowsheet.Double‐clickonit(probablycalledADJ‐1).RenameasAdjustAirRate.DefinetheAdjustedVariableasthemolarflowoftheAirstream.We’llusethecalculationforthedifferencebetweenthedesiredairrate&theactualastheTargetVariable;thisiscellD8intheAirRateCalcspreadsheet.SettheSpecifiedTargetValueas0.

Rev1.0 ‐23‐ February26,2015

Tofinishwehavetosetvaluestocontrolthecalculations.ClickontheParameterstab.Increasethenumberofiterations(heresetfrom10to100).Settheminimumallowedvalueto0&themaximumallowedvaluetosomethingabovetheactualvalue(heresetto100).ThestatusareawillswitchtoOKwheniterationsaecompleted.

WecanopenuptheAirRateCalcspreadsheet&seethattheAirflowratehasbeenadjustedtomatchtheexcessoxygenspecification.

TyingtheTwoSystemsTogether

Eventhoughthesteamcycle&fuelgassystemsareinthesameHYSYSflowsheettheyarereallymodeledseparately.Thesteamcyclehasconvergedwithabasisof1kg/secwatercirculationrate&thefuelsystemhasconvergedwithabasisof1kg.mol/secfuelgas.Wewilltiethesystemstogetherby“pushing”thedutyavailablefromthefuelsideoftheboilertothesteamside&adjustingthewatercirculationrateinthesteamcycle.

Rev1.0 ‐24‐ February26,2015

Beforewemakeanydirectconnectionslet’screateaspreadsheettosummarizetheresultsfromthetwosystems.FromtheModelPaletteaddaSpreadsheet;doubleclicktoopen.ChangethenametoOverallPerformance.ClickontheSpreadsheettab&setuptextfieldsthatlooklikethefigureontheright.

Associatethematerialflows,temperature,&energyflowsasshowninthefigureontheright.

Nowlet’sconnectthetwosystems.

Rev1.0 ‐25‐ February26,2015

DoubleclickontheCondensatestreaminthesteamcycleanddeletethevalueforthemassflowrate.Noticethattheintrinsicpropertiesforthestreamarestillcalculated(suchasthemolarenthalpy)buttheextrinsicpropertiesthatdependontheflowratearenowmissing.

Double‐clickontheiconfortheHRSGexchanger.GototheDesigntab&changetheEnergystreamfromQ‐HRSGtoQ‐Boiler.Thesimulationwillstillshowthatitiscomplete.YouwillwanttodeletetheunnecessarystreamQ‐HRSGfromtheFlowsheet.

Sowhat’schanged?Goback&lookattheCondensatestream.NoticethatHYSYShascalculatedawatercirculationratetomatchuptheamountofboilerheatneededinthesteamcycle(onakJ/kgbasis)withtheproperwaterflowrate(onakg/secbasis).

AdditionalStream&UnitAnalyses

Thereareadditionalanalysesthatwemaywanttoperformforthissimulation.Sincethegoaloftheprocessistocreatepowerweshouldbeveryinterestedtodeterminethevariousthermal

Rev1.0 ‐26‐ February26,2015

efficienciesofthesystems.WehavealreadystartedthisanalysisbyputtingcalculationsintotheSteamCycleSummaryspreadsheettocalculatethesteamcycle’sthermalefficiencybasedontheHYSYSresults.Tocalculatetheefficiencyoftheboilerweneedtodeterminetheheatingvalueofthefuelgasused.WehavealreadysetuptheformatoftheOverallPerformancespreadsheettodothesecalculations.OpentheOverallPerformancespreadsheetAssociatecellB3willtheHHV–right‐clickonthecell&chooseImportVariable;chooseFuelGas,HigherHeatingValue,thenclickOK.AssociatecellB4willtheLHV–right‐clickonthecell&chooseImportVariable;chooseFuelGas,LowerHeatingValue,thenclickOK.AddformulasintoD2&D3toputtheheatingonaflowingbasis(i.e.,multiplytheheatingvaluebythemolarflowrate).NotethateventhoughthenumbersappearunitlesstheyreallyhaveunitsofkJ/sec.Let’sadd2columnsfortheefficiencyvalues.GototheParameterstab&changethenumberofcolumnsfrom4to6.Setuplabelsasshownontheright.

Nowwewanttoaddformulastocalculatethevariousvalues:

Rev1.0 ‐27‐ February26,2015

cellF2,“=D4/D2”(alsochangeVariableTypetoUnitless) cellF3,“=D4/D3”(alsochangeVariableTypetoUnitless) cellF5,“=(D8‐D7)/D4” cellF7,“=(D8‐D7‐D6)/D2”(alsochangeVariableTypetoUnitless) cellF8,“=(D8‐D7‐D6)/D3”(alsochangeVariableTypetoUnitless)

TherearemanyothercapabilitiesthatcanbeaddedsincetheSpreadsheetoperationcanmakechanges&calculationsina“live”fashion.Forexample,anentirecontrolsheetcouldbesetuptomodifyvalues&directlycalculateresults.Cellscouldbesetupforthefollowinginputs:

Fuelgasflowrateanditspressure&temperature. Theair’satmosphericpressure&temperature. Air’shumidity(wouldalsorequireadditionaloperationstoproperlyaddwaterwhile

keepingtherestofthecomponents’relativeamountsthesame). Desiredexcessair. Pressuredropthroughtheboilersystem. Allowablestackoutlettemperature. Condensationtemperatureinthesteamcycle. Pressuredropthroughthesteamsideoftheboiler. Degreesofsuperheatintheboilersystem. Adiabatic&mechanicalefficienciesofallrotatingequipment.