SteamCycleSimulation–HYSYSv8.6
TheattachedgivesstepstosetupasimulationinHYSYSv8.6tomodelasimpleRankinesteam
cycleforelectricityproduction.Thesystemconsistingof:
 Fuelgassidewithairblower,combustionchamber,&fuelgassideofthesteamboiler.
 Steamsidewithsteamturbine,steamcondenser,condensatepump,&steamsideofthe
boiler.
Thesimulationwillfirstbesetupassumingisentropicstepsfortherotatingequipment.Itwillthen
bemodifiedtoaccountformorerealisticefficiencies(boththermodynamicandmechanical).
WhenthesimulationissetuptheoverallPFDshouldlooklikethefollowingfigure.
Createnewsimulationfile
StarttheprogramfromStart,AllPrograms,AspenTech,ProcessModelingV8.6,AspenHYSYS,Aspen
HYSYSV8.6.WhentheprogramopenschoosetheNewbutton.
Rev1.0
‐1‐
February26,2015
DefinetheComponents&thePropertyModels
Specifycomponents,fluidpropertypackages,&crudeoilassays
Thefirststepistoaddtwosetsofpurechemicalspeciestorepresent:
 Steamasmodeledbypurewater&usingpropertycorrelationsconsistentwiththeASME
SteamTables.
 Thenaturalgasfuel,air,&combustionexhaustaspurelightcomponentsmodeledbythe
Peng‐Robinsonequationofstate(EOS).
Let’sdothesteamfirst.WithComponentListshighlightedclickontheAddbutton.Fromthelistof
purecomponentspickwater.We’renowreadytopickthepropertymodel.
Rev1.0
‐2‐
February26,2015
Thenextstepistopickafluidpropertypackage.FromtheFluidPackagesscreenclicktheAdd
button.ChoosetheASMESteamoptionandmakesureitisassociatedwithComponentList–1.
Nowlet’saddcomponentstomodelthefuelsideofthesystem.GobacktotheComponentListsitem
&clickontheAddbuttontocreateComponentList‐2.Weneedcomponentsforthefollowing:
 Naturalgas.Fornowlet’smodelthisasapossiblemixtureofmethane,ethane,&propane.
 Air.Fornowwe’llmodelthisasamixtureofoxygen&nitrogen.
 Combustiongases.Attheminimumwe’llalsoneedcarbondioxideandwater.However,
we’llalsowanttotakeintoaccountincompletecombustion(formingcarbonmonoxide)as
wellasNOxformation(fornowjustasNO,NO2,&N2O).
Fromthelistofpurecomponentspickthefollowingchemicalspecies.Thenextstepistoassociatea
differentfluidpropertypackageforthesecompounds(sincetheASMESteamTablesareonly
appropriateforpurewater).GobacktotheFluidPackagesscreen&clicktheAddbutton.Choose
thePeng‐RobinsonoptionandmakesureitisassociatedwithComponentList–2.
Rev1.0
‐3‐
February26,2015
Nowisagoodtimetosavethefilebeforewestartsettinguptheprocesssimulation.ClicktheFile
tab&thentheSaveAsitem.
Rev1.0
‐4‐
February26,2015
Setup&SolvetheFlowsheet
WorkingUnits
ActivatetheSimulationoption.Notethatyou’llseeablankflowsheet.
WewouldliketoshowthecalculationswithamodifiedsetofSIunits,inparticular:
 Temperatureas°C.
 Pressureasbar(absolute).
 Massflowaskg/sec.
 Molarflowaskg.mol/sec.
 HeatdutyaskJ/sec.
 PoweraskW.
UndertheHometabclickthe
UnitSetsbutton.Underthe
AvailableUnitsSetsselectSI.
Youcanexaminethelist
underDisplayUnitsto
determinewhatwillbeused
forthedisplayoftheresults
aswellasthedefaultunits
fortheinput.Mostofthe
unitsarewhatwedesire,but
notall.Forexample,youcan
seethatPressurewillbe
reportedinkPa,notquite
whatwewant.
Let’screateanewsetof
units&callit“SI‐bar‐sec”.
WiththeSIunitshighlighted
intheAvailableUnitsSetslist
clicktheCopybutton.Change
theUnitSetNametoSI‐bar‐
sec.Let’snowexaminethe
DisplayUnitsfortheonesof
interest(Temperature,
Pressure,etc.)andmake
surethatareconsistentwith
whatwewant.Tochangewe
needonlyclickonthe
dropdownlistintheUnits
column.Forexample,to
changePressurefromkPato
barweonlyneedtochoose
theappropriateoptionfrom
thelist.Whendoneclickthe
OKbutton.
Rev1.0
‐5‐
February26,2015
SteamCycle
WewillwanttocreateasimpleRankinecyclewiththefollowingprocessconditions:
 Saturatedsteamproductionat125bar.
 Finalcondensationto20°C.
 Steamturbineoperatingatidealreversibleconditions.
 Condensatepumpoperatingatidealreversibleconditions.
 Noextrapressuredropthroughheatexchangersorpiping.
Let’splacethefollowingunitsfromtheModelPalettetotheflowsheet1:Heater,Cooler,Expander,&
Pump.Ultimatelyitwillbedepictedasfollows.
Let’sdefinethecondensatepumpfirst.
Doubleclickonthepumpicon(probably
calledP‐100).Changethenameto
CondensatePump.Specifynewstreams
fortheinlet,Condensate,theoutlet,HP‐
Water,&theenergystream,W‐Pump.
MakesurethattheBasis‐1fluidpackage
ischosen.
1IftheModelPaletteisnotvisiblechoosetheViewtab&clickontheModelPalettebutton.
Rev1.0
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February26,2015
Wewanttomakethisanidealreversible
pump.ClickontheParametersoption&
changetheAdiabaticEfficiencyto100%.
Wecaninitializethewatercirculatingintheloopfrom
here,too.ClickontheWorksheettab&choosethe
Compositionoption.Enter1fortheH2Ovalueunderthe
Condensatecolumn.Aninputformwillpopup&allow
youtoverifythatthisrepresentstheMolesFractions
basis.ClicktheOKbutton.
ClickonConditionssowecanentervalues
fortheCondensateenteringthepump.
SpecifytheTemperatureas20°Candthe
Vapourfractionas0(i.e.,asaturated
liquid).Let’suseaflowbasisof1kg/s.
NoticethatCondensatestreamisfully
defined&otherassociatedvaluesare
calculated(suchasthepressure,molar
flow,heatflow,etc.)
Nowlet’sdefinethesteamsideofthe
boiler.Doubleclickontheheatericon
(probablycalledE‐100).Changethename
toSteamBoiler.Pulldownthelistforthe
inputstream&chooseHP‐Water.Specify
newstreamsfortheoutlet,HP‐Steam,&
theenergystream,Q‐Boiler.Makesure
thattheBasis‐1fluidpackageischosen.
Rev1.0
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February26,2015
Wewanttoassumeanegligiblepressure
dropthroughthisexchanger.Clickonthe
Parametersoption&changetheDeltaPto
0.
Nowlet’sspecifytheconditionsforthe
highpressuresteam.Clickonthe
Worksheettab&theConditionsoption.
SpecifythePressureas125barandthe
Vapourfractionas1(i.e.,asaturated
vapor).
Noticethatafterenteringthepressurethe
restoftheconditionsfortheHP‐Water
streamarecalculated(sincewenowknow
theoutletpressureofthepump,too).After
enteringthevaporfractiontherestofthe
conditionscanbecalculatedfortheoutlet
HP‐Steam&therequireddutyQ‐Boiler.
Nowlet’sdefinethesteamturbine.
Doubleclickontheexpandericon
(probablycalledK‐100).Changethe
nametoSteamTurbine.Pulldownthe
listfortheinputstream&chooseHP‐
Steam.Specifynewstreamsforthe
outlet,TurbineExhaust,&theenergy
stream,W‐SteamTurbine.Makesure
thattheBasis‐1fluidpackageis
chosen.
Rev1.0
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February26,2015
Wewanttomakethisanideal
reversibleexpander.Clickonthe
Parametersoption&changethe
AdiabaticEfficiencyto100%.
Donotapplyanyotherconditionsatthistime.
Nowlet’sdefinethecondenser.
Doubleclickonthecoolericon
(probablycalledE‐101).Change
thenametoSteamCondenser.Pull
downthelistfortheinputstream
&chooseTurbineExhaust.Pull
downthelistfortheoutletstream
&chooseCondensate.Specifya
newenergystream,Q‐Condenser.
MakesurethattheBasis‐1fluid
packageischosen.
Wewanttoassumeanegligible
pressuredropthroughthis
exchanger.ClickontheParameters
option&changetheDeltaPto0.
Nowallunits&streamsshouldbefullycalculated.Therearevariouswaystoviewtheresults.One
wayistoclickontheWorkbookitem.UndertheMaterialStreamstabwecanseetemperatures,
pressures,&phaseconditions(i.e.,vaporfractions).UndertheEnergyStreamstabwecanseethe
calculatedexchangerduties&rotatingequipmentpowers.
Rev1.0
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February26,2015
Wecanalsoviewthisbasicinformationdirectlyontheflowsheet.Rightclickthevariousstreams&
choosetheShowTableoption.Thiscanbedoneforallofthestreamsofinterest.(Thetableswill
probablyhavetobemovedaroundtomaketheresultsreadable.)
Bydefaultthematerialstreamtablesshowthetemperature,pressure,&overallmolarflow.Toadd
vaporfractiondouble‐clickonthetable,clickAddVariable,chooseVapourFraction,clickOK,&
closethePFDTableform.
Rev1.0
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February26,2015
Thereisathirdoptionthatwouldallowyoutocalculatethethermalefficiencyofthesteamcycleas
wellassummarizetheresults–addaSpreadsheettothesimulation.
FromtheModelPaletteadd
aSpreadsheet;doubleclick
toopen.Changethenameto
SteamCycleSummary.Click
ontheParameterstaband
changetheNumberof
Columnstoatleast5and
theNumberofRowstoat
least11.Clickonthe
Spreadsheettab&setup
textfieldsthatlooklikethe
figureontheright.
Rev1.0
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February26,2015
Wenowwanttoassociatemanyof
thecelllocationstoresults
calculatedbyHYSYS.Forexample,
right‐clickoncellB2&choose
ImportVariable;choose
Condensate,Temperature,&then
clickOK.Notethatthetemperature
of20.00Cappearsinthetable;also
notethatitisformattedasbold
blue,meaningthatthisisauser‐
inputvalue.(Italsodenotesthatit
canbechangedfromhere,but
moreofthatlater.).
Whenallvariablesare
associatedwiththe
appropriatecellsthe
spreadsheetshouldlookas
follows.
Nowlet’saddacouplecalculations.
 ThenetpowerproducedwillbethatfromtheSteamTurbineminusthatneededbythe
CondensatePump.IncellD10entertheformula“=D8‐D9”.
 Wealsowouldtodirectlycalculatethethermalefficiencyofthesteamcycle,i.e.,theratioof
thenetpowerproducedbytheheatinfromtheboiler.IncellD11entertheformula
“=100*D10/B8”.
Rev1.0
‐12‐
February26,2015
Nowwehaveasummary
tablethatwillshowina
singleplacematerialstream
results,energystream
results,unitoperation
parameters,&calculated
results.Forexample,wecan
seethatthiscombinationof
conditionswillresultina
steamcyclewitha41.25%
thermalefficiency.
Notethatthisisalsoa“live”
table.Wecanchange
parametershere&the
othervalueswill
automaticallyrecalculate.
Forexample,ifwewereto
changetheSteamTurbine&
CondensatePumpadiabatic
efficienciesto85%,thenall
valueswouldbe
recalculatedandwecould
seethatthethermal
efficiencydropsto34.94%.
Fuel&CombustionSystem
Wewillwanttocreateasimplenaturalgasburner/boilerwiththefollowingprocessconditions:
 Naturalgasisavailableatindustrialdeliverypressure,20bar‐g&15°C.Wewill
characterizethenaturalgasas100%methane.
 Airisavailableat25°C.Wewillcharacterizetheairasa21/79O2/N2molarmixtureand
bonedry(i.e.,nowater).Wewanttoaddenoughairsothatthereis20%excessoxygen
basedoncompletecombustionofthenaturalgas.
 Thecombustionprocessoccursnearsatmosphericconditionssothenaturalgasmustbelet
downinpressure.However,ablowerisneededtopushtheairintothecombustion
chamber.
 Thepressuredropthroughtheburner/boiler/fluecombinationis0.3bar.
Rev1.0
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February26,2015

Thefluegasisexhaustedtotheatmosphereat120°C,atemperaturehighenoughtoprevent
anyliquiddropout&subsequentcorrosionproblems.
Let’splacethefollowingunitsfromtheModelPalettetotheflowsheet:Valve,Compressor,Gibbs
Reactor2,&Cooler.Ultimatelyitwillbedepictedasfollows.(We’lldiscusstheSpreadsheet,Set,&
Adjustoperationsaswego.)
Let’sdefinethenaturalgas&
let‐downvalvefirst.Double
clickonthevalveicon
(probablycalledVLV‐100).
ChangethenametoGasLet‐
DownValve.Specifynew
streamsfortheinlet,FuelGas,
&theoutlet,LP‐Fuel.Make
surethattheBasis‐2fluid
packageischosen.
2NotethatreactormodelsareundertheColumnstaboftheModelPalette.
Rev1.0
‐14‐
February26,2015
Wewillinitializethenaturalgasfromhere.
ClickontheWorksheettab&choosethe
Compositionoption.Enter1fortheMethane
valueundertheFuelGascolumn.Aninput
formwillpopup&allowyoutoverifythat
thisrepresentstheMolesFractionsbasis.
ClicktheNormalizebuttontosettheother
compositionsaszero.ClicktheOKbutton.
ClickonConditionssowecan
entervaluesfortheFuelGas
enteringthepump.Specifythe
Temperatureas15°Candthe
Pressureas20bar‐g(notethat
thepressuregetsautomatically
adjustedtoanabsolutebasis).
Let’suseaflowbasisof1
kg.mol/s.
Let’sspecifytheoutletpressure
of0.3bar‐gintheLP‐Fuel
column(notethatthepressure
getsautomaticallyadjustedtoan
absolutebasis).
NoticethatboththeFuelGas&LP‐Fuelstreamsarefullydefined&otherassociatedvaluesare
calculated(suchasthemassflow,heatflow,etc.)
Rev1.0
‐15‐
February26,2015
Nowlet’sdefinethe
air&theairblower.
Doubleclickonthe
compressoricon
(probablycalled
K‐100).Changethe
nametoAirBlower.
Specifynew
streamsforthe
inputstream,Air,
theoutlet,Air‐2,&
theenergystream,
W‐AirBlower.Make
surethattheBasis‐
2fluidpackageis
chosen.
Wewanttomake
thisanideal
reversible
compressor.Click
ontheParameters
option&changethe
AdiabaticEfficiency
to100%.
Rev1.0
‐16‐
February26,2015
Wewillinitializetheairstreamfromhere.
ClickontheWorksheettab&choosethe
Compositionoption.Enter0.21forthe
OxygenvalueundertheAircolumn.An
inputformwillpopup&allowyoutoverify
thatthisrepresentstheMolesFractions
basis&finishenteringtherestofthevalues.
Enter0.79fortheNitrogenvalue.Clickthe
Normalizebuttontosettheother
compositionsaszero.ClicktheOKbutton.
ClickonConditionsso
wecanentervalues
fortheAirentering
thepump.Specifythe
Temperatureas25°C
andthePressureas0
bar‐g(notethatthe
pressuregets
automatically
adjustedtoan
absolutebasis).Asa
startingpointlet’s
definetheflowrateas
12kg.mol/hr.
Finally,let’sspecify
theoutletpressurefor
Air‐2as0.3bar‐gto
matchthatofthefuel
gasafterthelet‐down
valve.
NoticethatboththeAir&Air‐2streamsarefullydefined&otherassociatedvaluesarecalculated
(suchasthemassflow,heatflow,etc.)
Nowit’stimetomodelthecombustionportionofthefuelgasburner.Therearevariousoptionsfor
doingthis.Oneofthesimplest(andwouldnormallybedoneforhandcalculations)wouldbeto
defineallcombustionreactions&specifytheextentofconversionforeach.Instead,we’regoingto
takeadvantageofthefullthermodynamiccapabilitiesofHYSYS&useareactorthatwillminimize
theGibb’sfreeenergy.Allwehavetodoislisttheexpectedproducts&HYSYSwillcalculatethe
resultingproductdistributionthathonorsthematerial&energybalancesaswellasanychemical
equilibriumlimitations.
Rev1.0
‐17‐
February26,2015
DoubleclickontheGibbs
Reactoricon(probably
calledGBR‐100).Change
thenametoCombustion.
SelecttheexistingLP‐Fuel
&Air‐2streamsasinlets.
Specifynewstreams,
CombustionGas,asthe
vapouroutlet&
CombustionLiquidsasthe
liquidoutlet.Makesure
thattheBasis‐2fluid
packageischosen.
That’sprettymuchit.The
defaultsarezeropressure
drop&includeallspecies
inthecomponentlistas
potentialproduct.
Wecanexaminethe
resultsbyclickingonthe
Worksheettab.Selecting
Conditionsshowsthat
thereisonlyagas
producedatatemperature
of1731°C.Wecanthen
lookattheresulting
compositionbyselecting
Composition.Theresults
are,bydefault,shownas
molefractions.Notethat
allofthemethanehas
beenconsumed.Thereisa
smallamountofCO
formed(asincomplete
combustion)butsome
NOxhasalsobeencreated
fromtheN2intheair.
Nowlet’sseehowmuchheatcanbetransferredoutofthecombustiongases.
Rev1.0
‐18‐
February26,2015
Nowlet’sspecifythe
combustiongassideofthe
boiler.Doubleclickonthe
heatericon(probablycalled
E‐100).Changethenameto
HRSG.Pulldownthelistfor
theinputstream&choose
CombustionGas.Specifynew
streamsfortheoutlet,Flue
Ga,&theenergystream,Q‐
HRSG..Makesurethatthe
Basis‐2fluidpackageis
chosen.
Wewillnotspecifyapressure
dropacrosstheexchanger.
Rather,we’llspecifythe
pressureoutthestack.Click
ontheWorksheettab&the
Conditionsoption.Specifythe
Pressureas0bar‐gandthe
Temperatureas120°C.
Nowtheconditionsforthe
inlet&outletstreamscanbe
determinedaswellasthe
dutyavailable(asQ‐HRSG).
Therearestillacoupleitemstobedoneto“cleanup”thesimulation.Thefirstisforamatterof
convenience–howshouldwespecifythepressureoftheAir‐2streamoutoftheblower?Rightnow
thepressureintotheCombustionoperationissetseparatelyforthetwoinletstreams(LP‐Fuel&
Air‐2).Ifastudywastobeperformed&thepressureweretochangethenhavingthespecifications
intwoseparatelocationscouldleadtothembeingchangeddifferently.Itsurewouldbenicetoset
itonlyinonelocation&thenhavetheotherlocationupdateautomatically.Wecandothiswitha
Setoperation.
FromtheModelPaletteplaceaSetoperationonthe
flowsheet.Double‐clickonit(probablycalledSET‐1).
RenameasSetBlowerOutlet.DefinetheTargetVariable
asthepressureoftheAir‐2stream.We’llusetheSource
asthevaluefromLP‐Fuel.
Oncethisisimplementedanychangesmadetothe
pressureofLP‐Fuelwillbeautomaticallytransmittedto
theoutletpressureoftheairblower.
Rev1.0
‐19‐
February26,2015
Thesecondchangeinvolvesaconvenientwaytomakesurethatthecorrectamountofairisadded
tomatchthe“excessoxygen”spec.Theamountofstoichiometricoxygenisdeterminedfromthe
combustionreactions.Formethane,ethane,&propanethereactionsare,respectively:
CH4+2O2CO2+2H2O
C2H6+3.5O22CO2+3H2O
C3H8+5O23CO2+4H2O
Thisshowsthatweneedtoknowthecompositionofthefuelgas(inmolaramounts)todetermine
thestoichiometricamountofoxygenneeded.The“excess”partisadditionaloxygen(asa
multiplier)thatisadded.ThefinalconsiderationisthatthespecificationinHYSYSisnotjustforthe
rateofoxygenbutratheroftheair;sowehavetotakeintoaccountthecompositionoftheair
accountforthelargeamountofnitrogenalsobeintroducedintotheCombustionoperation.
Sincewehavesetthecompositionofthefuelgastobepuremethane&thebasisflowrateto1
kg.mol/secthenthestoichiometricoxygenflowrateistwicethis,2kg.mol/sec.Wealsoneedto
increasethisby20%toincludethedesiredexcess.Andweneedtotakeintoaccounttheoxygen
contentintheairtodeterminetheairrate.Sooverall:
nO2
1  fexcess  2 1  0.2
stoich

 11.43kg.mol/sec .
nair 
0.21
yO2
 
WecoulddothesecalculationspriortorunningHYSYSandentertheairrate.Orwecoulddothe
calculationswithinHYSYS.
FromtheModelPaletteadd
aSpreadsheet;doubleclick
toopen(probablycalled
SPRDSHT‐1).Changethe
nametoAirRateCalc.Use
thedefaultnumberofrows
&columns.Clickonthe
Spreadsheettab&setup
textfieldsthatlooklikethe
figureontheright.
Rev1.0
‐20‐
February26,2015
Wenowwantto
associatemanyof
thecelllocations
toresults
calculatedby
HYSYS.For
example,right‐
clickoncellD3&
chooseImport
Variable;choose
Air,Mast
ComponentMole
Frac,Oxygen,&
thenclickOK.
Let’sassociateallofthe
desiredmolarflowrates.
Forexample,forthefuel,
right‐clickoncellB4&
chooseImportVariable;
chooseFuelGas,Molar
Flow,&thenclickOK.
Associatethemolarflowfor
theairtothecellD7.
Nowlet’saddthefollowingcalculations:
 cellD4,“=(B2*2+B3*3.5+B4*5)*B5”
 cellD4,“=D4*(1+D2)”
 cellD4,“=D5/D3”
 cellD4,“=D7‐D6”
Rev1.0
‐21‐
February26,2015
Nowwehaveatablethat
willcalculatethedesiredair
flowrateforthespecified
fuelgasflowrate.Though
thespreadsheetcannot
directlysettheairflowrate
wecandoitmanuallyby
directlychangingthevalue
incellD7.
EventhoughthespreadsheetitselfcannotdirectlysettheflowrateoftheAirstreamitcanbeused
aspartofanAdjustoperation.
FromtheModelPaletteplacean
Adjustoperationonthe
flowsheet.Double‐clickonit
(probablycalledADJ‐1).
RenameasAdjustAirRate.
DefinetheAdjustedVariableas
themolarflowoftheAirstream.
We’llusethecalculationforthe
differencebetweenthedesired
airrate&theactualasthe
TargetVariable;thisiscellD8in
theAirRateCalcspreadsheet.
SettheSpecifiedTargetValueas
0.
Rev1.0
‐22‐
February26,2015
Tofinishwehavetosetvalues
tocontrolthecalculations.Click
ontheParameterstab.Increase
thenumberofiterations(here
setfrom10to100).Setthe
minimumallowedvalueto0&
themaximumallowedvalueto
somethingabovetheactual
value(heresetto100).The
statusareawillswitchtoOK
wheniterationsaecompleted.
WecanopenuptheAirRate
Calcspreadsheet&seethat
theAirflowratehasbeen
adjustedtomatchtheexcess
oxygenspecification.
TyingtheTwoSystemsTogether
Eventhoughthesteamcycle&fuelgassystemsareinthesameHYSYSflowsheettheyarereally
modeledseparately.Thesteamcyclehasconvergedwithabasisof1kg/secwatercirculationrate
&thefuelsystemhasconvergedwithabasisof1kg.mol/secfuelgas.Wewilltiethesystems
togetherby“pushing”thedutyavailablefromthefuelsideoftheboilertothesteamside&
adjustingthewatercirculationrateinthesteamcycle.
Rev1.0
‐23‐
February26,2015
Beforewemakeanydirect
connectionslet’screatea
spreadsheettosummarize
theresultsfromthetwo
systems.FromtheModel
PaletteaddaSpreadsheet;
doubleclicktoopen.
ChangethenametoOverall
Performance.Clickonthe
Spreadsheettab&setup
textfieldsthatlooklikethe
figureontheright.
Associatethematerial
flows,temperature,&
energyflowsasshownin
thefigureontheright.
Nowlet’sconnectthetwosystems.
Rev1.0
‐24‐
February26,2015
DoubleclickontheCondensate
streaminthesteamcycleanddelete
thevalueforthemassflowrate.
Noticethattheintrinsicproperties
forthestreamarestillcalculated
(suchasthemolarenthalpy)butthe
extrinsicpropertiesthatdependon
theflowratearenowmissing.
Double‐clickontheiconfortheHRSG
exchanger.GototheDesigntab&
changetheEnergystreamfromQ‐HRSG
toQ‐Boiler.Thesimulationwillstill
showthatitiscomplete.
Youwillwanttodeletethe
unnecessarystreamQ‐HRSGfromthe
Flowsheet.
Sowhat’schanged?Goback&look
attheCondensatestream.Noticethat
HYSYShascalculatedawater
circulationratetomatchupthe
amountofboilerheatneededinthe
steamcycle(onakJ/kgbasis)with
theproperwaterflowrate(ona
kg/secbasis).
AdditionalStream&UnitAnalyses
Thereareadditionalanalysesthatwemaywanttoperformforthissimulation.Sincethegoalofthe
processistocreatepowerweshouldbeveryinterestedtodeterminethevariousthermal
Rev1.0
‐25‐
February26,2015
efficienciesofthesystems.Wehavealreadystartedthisanalysisbyputtingcalculationsintothe
SteamCycleSummaryspreadsheettocalculatethesteamcycle’sthermalefficiencybasedonthe
HYSYSresults.
Tocalculatetheefficiencyoftheboilerweneedtodeterminetheheatingvalueofthefuelgasused.
WehavealreadysetuptheformatoftheOverallPerformancespreadsheettodothesecalculations.
OpentheOverall
Performancespreadsheet
AssociatecellB3willthe
HHV–right‐clickonthe
cell&chooseImport
Variable;chooseFuelGas,
HigherHeatingValue,then
clickOK.AssociatecellB4
willtheLHV–right‐click
onthecell&choose
ImportVariable;choose
FuelGas,LowerHeating
Value,thenclickOK.Add
formulasintoD2&D3to
puttheheatingona
flowingbasis(i.e.,multiply
theheatingvaluebythe
molarflowrate).
Notethateventhoughthe
numbersappearunitless
theyreallyhaveunitsof
kJ/sec.
Let’sadd2columnsforthe
efficiencyvalues.Gotothe
Parameterstab&change
thenumberofcolumns
from4to6.Setuplabels
asshownontheright.
Nowwewanttoaddformulastocalculatethevariousvalues:
Rev1.0
‐26‐
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)
TherearemanyothercapabilitiesthatcanbeaddedsincetheSpreadsheetoperationcanmake
changes&calculationsina“live”fashion.Forexample,anentirecontrolsheetcouldbesetupto
modifyvalues&directlycalculateresults.Cellscouldbesetupforthefollowinginputs:
 Fuelgasflowrateanditspressure&temperature.
 Theair’satmosphericpressure&temperature.
 Air’shumidity(wouldalsorequireadditionaloperationstoproperlyaddwaterwhile
keepingtherestofthecomponents’relativeamountsthesame).
 Desiredexcessair.
 Pressuredropthroughtheboilersystem.
 Allowablestackoutlettemperature.
 Condensationtemperatureinthesteamcycle.
 Pressuredropthroughthesteamsideoftheboiler.
 Degreesofsuperheatintheboilersystem.
 Adiabatic&mechanicalefficienciesofallrotatingequipment.
Rev1.0
‐27‐
February26,2015