Read 2007 Office of Fossil Energy Fuel Cell Program Annual Report text version

II.3 Coal Gas Fueled SOFC Hybrid Power Systems with CO2 Separation

Accomplishments

JosephF.Pierre

Manager,GovernmentPrograms SiemensPowerGeneration StationaryFuelCells(SFC) 1310BeulahRoad Pittsburgh,PA15235 Phone:(412)256-5313;Fax:(412)256-2012 E-mail:[email protected]

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Evaluatedmultipleproof-of-conceptandbaseline systemcandidatecycleconcepts. Developedafigure-of-meritsystemwithwhichthe candidatesystemsaretobecompared. Redefinedthereferencecycleconceptforthe baselinepowersystemtoalesscomplextechnology basisthatshouldprovideformorereliable implementation. identifiedapreferredcycleconfigurationforthe proof-of-conceptsystem. Optimizedthehighpowerdensity(HPD)DELTAncellgeometryfortheairfeedtubeandaxialfuel flowconfiguration. SuccessfullyextrudedandsinteredHPDDELTA-n tubes. Completedtheconceptualdesignofthemostcritical stackcomponents. Completedshakedownofthepressurizedcelltest facility.

DOEProjectManager:TravisShultz

Phone:(304)285-1370 E-mail:[email protected]

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Objectives

· · · OptimizationoftheSiemensDELTA-nsolidoxide fuelcell(SOFC)andscale-upofitsdimensions. Verificationbytestofcell,stack,andmoduleon coal-derivedsyngas. Corroborationofthetechnicalandeconomic feasibilityofa>50%efficientSOFC-basedlarge capacity(>100MWe)coal-fueledbaselinepower plant. Testoncoalsyngasofafullyfunctional50% efficientproof-of-concept(POC)oflessermultiMWecapacity.

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Future Directions

· · Optimizebaselinecycleconfiguration. updateandinitiateconceptualdesignofproof-ofconceptsystembasedonoptimizedbaselinesystem configuration. Executecellandstackperformancetest. Optimizeatmosphericplasmaspray(APS)operating parameters. Continuetheconceptualdesignforthemodule.

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Approach

· · · · · · AnalyticalmodelingtooptimizetheDELTA-ncell geometry. Developaviablecellmanufacturingprocessand fabricatecells. Verifybyparametrictestingcellperformanceand durability. Analyze,design,anddevelopafuelcellstack. Preparethepreliminarydesignofamodule aggregatingfuelcellstacks. Testathermallyself-sustainingfuelcellstackon simulatedcoalsyngasatthepowersystemoperating pressure. identifyandanalyzecycleconcepts. Selectabaselinesystemcycle. Preparetheconceptualdesignforthebaseline system. Corroborateviaindependentauditthetechnicaland economicfeasibilityofthebaselinesystem. Developtheconceptualdesign,performance analysis,andcostanalysisforthePOCsystem.

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Introduction

SiemensPowerGenerationSFCwilldevelopa MWe-classsolidoxidefuelcellpowersystemtooperate oncoal-derivedsynthesisgasanddemonstrateoperation atgreaterthan50%electricalefficiency(basishigher heatingvalue[HHV]coal)withgreaterthat90%CO2 capture.Thesystemwillbescalabletosizesgreater than100MWeoutputand,whenofferedincommercial quantities,willhaveatargetcostof$400/kWeincluding anyextraordinarycostsofintegrationtothebalance ofplant.Corroborationofthetechnicalandeconomic feasibilityoftheSOFCpowersystemwillbeachieved throughtheconceptualdesignofalarge[>100MWe] baselinepowerplantandthesubsequentdesign, development,fabrication,andtestofaproof-of-concept system.ThePOCwillhaveanidenticalcycle,beof

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FY 2007 Annual Report

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Office of Fossil Energy Fuel Cell Program

II. SECA Fuel Cell Coal-Based Systems

multi-MWecapacity,anddemonstrateanelectrical efficiency>50%(coalHHV). Theproposedcycleconceptwasredevelopedas thegasturbineandtheiontransportmembrane(iTM), respectively,wereremovedfromthecycle,theSOFC systemisnowatatmosphericpressure,andasteam turbinebottomingcyclehasbeenintegratedintothe heatrecoverysystem.Thereferencecycleincludesan oxygen-blowngasificationsystemwithconventional cleanupandscrubbingtoproduceasyngasrichin hydrogenandcarbonmonoxide.Aftershifting,the CO2isremovedfromthesyngasviaalow-temperature polymermembrane.Oxygenforthegasificationprocess issuppliedbyacryogenicairseparationunit. ThisreferencecycleSOFC/steamturbine(ST) configurationislesscomplexthanitspredecessorand shouldprovideformorereliableimplementationatthe POClevel.Operatingatambientpressure,theSOFC systemiscomposedofmultiple,identicalSOFCmodules thatreceivepreheatedairfromtheheatrecoverysystem. TheSOFCmodulesarebaseduponthehighpower densityDELTA-ncellgeometry,developedwithinthis project.Cellandstackperformanceanddurabilitywill beverifiedviaperformancetestingofsingleandmultiple cells(bundles).

Joseph F. Pierre

widthwillbeoptimizedbasedonpracticallimitations forcellfabricationandgeneratorutility.Theoptimized DELTA-ncellswillbebundledintoanarrayorbundle (stack)ofelectricallyconnectedfuelcellsforming amonolithicstructure.Atypicalstackwillconsist ofbundlesconnectedinseriesarrangedinparallel rows.TheproposedSOFCstackconceptisbasedon technologythathasbeendevelopedandprovenaspart ofpreviousgeneratordesignandtestingprograms,a seriesofatmosphericandpressurizedbundletests,and the220kWepressurizedSOFCgeneratordesigned, builtandoperatedinthepressurizedSOFC/gasturbine (PSOFC/GT)hybridpowersystem.Furtherinnovation willberequired,particularlyindevelopmentoflow-cost ceramicmaterials,netshapecomponentfabrication,and ahighpowerdensitystackconfigurationtoreducethe overallcostofthesystem.Cellandstackperformance willbecharacterizedviaaseriesofsingleandmulti-cell tests.

Results

Anumberofcycleconfigurationsforthebaseline systemhavebeenidentifiedandevaluated.Afigure-ofmeritsystemforselectingthepreferredcandidatewas developedandemployedinarigorousdownselection process.Apreferredbaselinesystemconfiguration wasidentified.Thepreferredbaselinesystem,shown inFigure1,meetstheefficiencyobjective,employsthe seal-lessSOFCcellandmoduleconfiguration,andhas thepotentialtousealowtemperature,lowcomplexity polymermembraneCO2separationsystem. Aseal-lessmoduleconfigurationthatfeaturesan airfeedtubeandanaxialfuelflowwasdeveloped,a resultofaninvestigationevaluatingnumerousstack configurations.Also,asaresultofnumerousfinite elementanalyses(FEA),thedimensionsoftheDELTAncellwereoptimized.Basedonthesedimensions,an optimizationofthevariouslayersofthecelltominimize electricalperformancelossesandinternalstresseswas initiated.Thevalidationoftheoptimizedcellgeometry commencedviathesuccessfulextrusionandsinteringof anumberofDELTA-ntubes.Thesetubesarenowbeing usedtooptimizetheAPSoperatingparameters.

Approach

ThebaselineSOFC/STpowersystemisfueledby coal-derivedsyngas.Theoverallobjectivesarehigh electricalefficiencyandCO2separationcapability.The baselinesystempowercapacityistoexceed100MWe whereastheproof-of-conceptsystemistobeinthe10 MWe-classrange.Severalcandidatecycleconfigurations wereidentifiedthatcouldbeimplementedatthe>100 MWelevel.Theseconfigurationsweremodeledto estimateelectricalefficiencyofthesystemandvalues ofkeyoperatingparameters(e.g.massflowrate, temperature,andpressure)formajorcomponents.Also tobeconsideredinadditiontosystemefficiencyare costasreflectedbysystemcomplexityandthepotential forPOCtestingatthe10MWe-classcapacity.The efficiencytargetforthePOCis50%(netAC/coal HHV). SFCisdevelopinganewcellandstackdesign thatcombinestheseal-lessstackfeatureandacell withaflattenedmulti-connectedtubularcathodewith integralribs.Thisnewdesignhasaclosedendsimilar totheSiemenscirculartubulardesign.Analytical modelingwillbeutilizedtooptimizethenumberand dimensionsofribsformaximumpower,thedistribution offuelflowandairflow,andstructuralstabilityagainst thermalstressesduringoperationfromatmospheric toelevatedpressure.Additionally,activelengthand

Conclusions

Systemsanalysisindicatetheperformance objectives(>50%electricalefficiency,netAC/coal HHV)canbeachievedandexceededwiththesuccessful implementationofimprovementsinSOFCmodule andbalance-of-plantcomponenttechnologies,incell andmoduleefficiencies,andadvancedmaterialsand fabricationprocessesfortheDELTA-ncell.

Office of Fossil Energy Fuel Cell Program

FY 2007 Annual Report

Joseph F. Pierre

Water Supply/ Treatment System

Syngas from Gas Scrubbing

II. SECA Fuel Cell Coal-Based Systems

Water

AC AC AC CO2 CO2 Separation G Syngas Expander/ Generator SOFC Exhaust DC Heat Recovery and Recuperator Evap Steam Generator

SH HTR Econ LTR Econ

Desulfurizer Coal GSP Coal Gasifier Water-Gas Shift Reactor

PCS

Water (Recycle)

CZ A C Air

Exhaust

Air

G SOFC Fuel Expander/ Generator

SOFC Fuel

SOFC Generator Module

Fuel Heater Feedwater Low-Pressure Steam From Gasifier SOFC Main Air Blower

AC Air

Low-Grade Heat Rejection CO2 Membrane Oxygen SOFC Fuel (High Pressure) CO2 / H2 Low Pressure N2 Air Separation Unit CG-54A Air M CO2 Blower

Combustor G

Oxy-

Oxygen

Steam Turbine/ Generator Deaerator Medium-Pressure Steam To Gasifier

Condenser

Makeup

FiguRe 1. Baseline SOFC/ST Power System, Reference Cycle

FY 2007 Annual Report

Office of Fossil Energy Fuel Cell Program

Information

2007 Office of Fossil Energy Fuel Cell Program Annual Report

3 pages

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