“Reaction Engineering of ...yte Membrane Fuel Cells”的预览.pdf

《“Reaction Engineering of ...yte Membrane Fuel Cells”的预览.pdf》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、12‑11‑28ReactionEngineeringofPolymerElectrolyteMembraneFuelCellsReactionEngineeringofPolymerElectrolyteMembraneFuelCellsAnewapproachtoelucidatetheoperationandcontrolofPolymerElectrolyteMembrane(PEM)fuelcellsisbeingdeveloped.Aglobalreactorengineeringap

2、proachisappliedtoPEMfuelcellstoidentifytheessentialphysicsthatgovernthedynamicsinPEMfuelcells.ReactionengineeringprinciplesareemployedtodevelopaonedimensionaldifferentialPEMfuelcellsuitableforelucidatingthedynamicperformanceofPEMcellsunderwelldefinedc

3、onditions.PolymerElectrolyteFuelCellsPolymerelectrolytemembrane(PEM)fuelcellsemployapolymermembranewithacidsidegroupstoconductprotonsfromtheanodetocathode.WatermanagementinthefuelcelliscriticalforPEMfuelcelloperation.Sufficientwatermustbeabsorbedintot

4、hemembranetoionizetheacidgroups;excesswatercanfloodthecathodeofthefuelcelldiminishingfuelcellperformancelimitingthepoweroutput.AschematicofapolymerelectrolytemembranehydrogenoxygenfuelcellisshowninFigure1.Figure1.HydrogenoxygenPEMfuelcell.Hydrogenmole

5、culesdissociativelyadsorbattheanodeandareoxidizedtoprotons.Electronstravelthroughanexternalloadresistance.ProtonsdiffusethroughthePEMunderanelectrochemicalgradienttothecathode.Oxygenmoleculesadsorbatthecathode,arereducedandreactwiththeprotonstoproduce

6、water.TheproductwaterisabsorbedintothePEM,orevaporatesintothegasstreamsattheanodeandcathode.ProtonconductivityinNafion,andmostotherpolymerelectrolytes,increaseswithwateractivity,andismaximizedwhenequilibratedwithliquidwater(wateractivityaw=1).Operatio

7、nataw=1minimizesthemembraneresistanceforprotonconduction,butresultsinwatercondensationwhichinhibitsmasstransfertotheelectrodes.OurresearchisfocusedonfindingoptimaloperationalandcontrolschemesforwatermanagementinPEMfuelcells.TheFuelCellasaChemicalReact

8、orThedynamicresponseoffuelcellsisessentialfortransportationapplicationswherethepowerdemandwillneedtorespondtovariableloads.WehavedevelopedaonedimensionaldifferentialreactorthatfunctionsasaStirredTankReactorPEMfuelcelltostudyfuelcelldynamics.Th