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Development of Calcium Oxide Solid Reactants for the UT-3 Thermochemical Cycle to Produce Hydrogen from Water

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DEVELOPMENTOFCALCIUMOXIDESOLIDREACTANTFORTHEUT-3THERMOCHEMICALCYCLETOPRODUCEHYDROGENFROMWATERByBENJAMINGRANTHETTINGERATHESISPRESENTEDTOTHEGRADUATESCHOOLOFTHEUNIVERSITYOFFLORIDAINPARTIALFULFILLMENTOFTHEREQUIREMENTSFORTHEDEGREEOFMASTEROFSCIENCEUNIVERSITYOFFLORIDA2005

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Copyright2005byBenjaminGrantHettinger

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iiiACKNOWLEDGMENTSManypeoplehaveassistedmeinthepastyearandahalfwiththisthesisprojecthereattheUniversityofFlorida.Icouldnothavecompletedthistaskwithoutthehelpthesepeoplewhogavemetheirtime,taughtmeknowledge,challengedmetothinkcritically,andsupportedmethroughouttheproject.IthankDr.D.YogiGoswamifortheopportunitytoinvestigatethischallengingresearchprojectandhisencouragementtoinvestigateallaspectsoftheproject.Ithankmycommitteemembers,S.A.Sherif,Dr.H.Ingley,andDr.H.Hagelin-Weaver,fortheiradviceandsupportthroughouttheproject.IthankDr.Deshpandeforhistirelesseffortstoaidmeinunderstandingthesubjectofmyresearch,forcontinuingtopushmetostaydiligent,forhelpingmewriteandeditmythesis,andforbeingahelpfuladvisor.Hehasbeenthereateverystepofthisprojectandhelpedtoimpartacademicknowledgeinmanyaspectsofresearch.Hehasespeciallyhelpedmetomorequicklygraspthechemicalengineeringandchemistrywhichencompassthemajorityofthisproject.IthankChuckG.forteachingmehowtousemanyofthetoolsattheshopandalsoforimpartingonmepracticalengineeringknowledgeandcriticalthinking.Ialsoamgratefulforthemembersofthelabgroupthatadvisedmeonsolutionstoproblemsinresearch,challengedmetoinvestigateproblemsfurther,andwhohelpedmetofindandtouseitemsinthelab.

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ivIhadalotofhelpatthedifferentfacilitiesandwiththevarietyofequipmentIused.IthankDr.AnghaiandTomCarterandthoseatthenuclearlaboratoryfortheuseoftheirfacilitiesandfriendlyandhelpfulassistance.IalsothankDr.HahnfortheuseofthehisaidinunderstandingRamanspectroscopyandX-Raydiffraction.IthankGaryScheiffeleforhistrainingonRamanspectroscopyandmercuryporosimetryandhiswillingnesstohelpmeunderstandtheiruseandlimitations.IthankGillBrubakerforhistrainingontheNOVAmachinefornitrogenadsorptionanalysis.IwouldalsoliketothankotherpeopleattheParticleScienceEngineeringbuildingwhohelpedtoorientmewithuseoftheirequipment.IacknowledgefinancialsupportfromtheUSDepartmentofEnergywhichallowedmetoinvestigatethisproject.WithoutthesepeopleIcouldnothavefinishedmyproject.Ithankmyparents,JeanandGlennHettinger,andtherestofmyfamilyintheirconstantsupportofmyeducation.IthankmyfriendsandKappaSigmafraternitybrothersfortheirsupportandhelpovertheyears.MostofallIthankmyLordJesusChristwhohassustainedmethroughlifethusfarespeciallyduringthetoughtimes.

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vTABLEOFCONTENTSpage ACKNOWLEDGMENTS.................................................................................................iiiLISTOFTABLES.............................................................................................................ixLISTOFFIGURES............................................................................................................xLISTOFSYMBOLS.......................................................................................................xiiiABSTRACT....................................................................................................................xviCHAPTER1INTRODUCTION......................................................................................................1CurrentHydrogenProductionMethods......................................................................1FossilFuels.............................................................................................................2Steammethanereformation................................................................................2Partialoxidationmethod.....................................................................................3Coalandbiomassgasification............................................................................3Electrolysis..............................................................................................................4ThermalDecompositionofWater..........................................................................5ThermochemicalProcesses.....................................................................................6PhotoelectricalandPhotochemicalHydrogenProduction.....................................6BiologicalHydrogenProduction............................................................................7ThermochemicalCycles..............................................................................................7IspraMarkProcesses..............................................................................................7Sulfur-IodineorMark16orGAProcess................................................................9MetalOxides.........................................................................................................10MiscellaneousProcesses.......................................................................................122THEUT-3THERMOCHEMICALPROCESS........................................................13HistoryofResearchontheUT-3ThermochemicalProcess.....................................14ProcessandSimulationStudies............................................................................15Membrane,SeparationTechniques,andMaterials...............................................22SolidReactants......................................................................................................24Ironreactants.....................................................................................................24Calciumreactants..............................................................................................27

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viStrengthsandWeaknessesoftheUT-3ThermochemicalProcess.......................33CalciumOxideSolidReactant..................................................................................34PhysicalCharacteristics........................................................................................35Porosity.............................................................................................................35Strength.............................................................................................................35ChemicalCharacteristics......................................................................................36Chemicalcomposition......................................................................................36Reactivity..........................................................................................................36Degradation.......................................................................................................37ResearchObjective...................................................................................................37ChemistryFormulation.........................................................................................38PhysicalFormation...............................................................................................393SOLIDREACTANT................................................................................................40Sol-GelChemistry....................................................................................................40Hydrolysis.............................................................................................................41Condensation.........................................................................................................42ChemicalFormulation..........................................................................................44Qualitativeinvestigation...................................................................................44Originalprocedure............................................................................................45Modifiedprocedure...........................................................................................48Mixingratios.....................................................................................................52PhysicalProcedures..................................................................................................52Drying...................................................................................................................52Molding.................................................................................................................53Hydraulicpress.................................................................................................53Originalmold....................................................................................................54Modificationsinmoldandmoldingprocedure.................................................57Sintering................................................................................................................584ANALYTICALTOOLS...........................................................................................61NitrogenAdsorption.................................................................................................61BETIsotherm............................................................................................................62BJHPoreSizeDistribution.......................................................................................63MercuryPorosimetry................................................................................................65Theory...................................................................................................................65Procedure..............................................................................................................66RamanSpectroscopy.................................................................................................66Theory...................................................................................................................66Procedure..............................................................................................................67ChemicalTesting......................................................................................................68Theory...................................................................................................................68Procedure..............................................................................................................68

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vii5EVALUATIONOFPARAMETERS.......................................................................69CorrelationsfromOriginalChemistry......................................................................69MoldingProcedure:Strength................................................................................70HeatingProcedure:StrengthandMicroporosity..................................................70Chemistry:ChemicalComposition.......................................................................72CorrelationsfromModifiedChemistry....................................................................73MoldingProcedure:StrengthandMacroporosity.................................................73Chemistry:Macroporosity,Microporosity,Composition,andStrength..............74HeatingProcedures:Composition,Strength,andPorosity...................................79OptimumParameters................................................................................................806RECOMMENDATIONSFORFUTUREWORK...................................................84ShortTermPlan........................................................................................................85InvestigationintoReactivity.................................................................................85Reactionrates....................................................................................................85Conversion........................................................................................................86InvestigationofDegradation.................................................................................86InvestigationofCyclicStrength...........................................................................87CreativeEngineering............................................................................................87LongTermPlan........................................................................................................87MassProductionofPellets....................................................................................87PelletPerformanceinaFixedBedReactor..........................................................887SUMMARYANDCONCLUSIONS.......................................................................89APPENDIXACHEMICALPROPERTIES.....................................................................................91BRAMANSPECTROMETER....................................................................................92CPELLETMAKINGPROCEDURES........................................................................94OriginalChemistry....................................................................................................94ModifiedChemistry..................................................................................................94DryingandPreheating..............................................................................................96Molding.....................................................................................................................96HeatingProcedures...................................................................................................97

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viiiDPELLETCHARACTERIZATIONPROCEDURES................................................98NitrogenAdsorption.................................................................................................98OutgassingProcedure...........................................................................................98FullIsothermAnalysisProcedure.........................................................................99QuantachromeMercuryPorosimeter......................................................................102FillingApparatusProcedure...............................................................................102HighPressureProcedure.....................................................................................104ERAMANSPECTRA...........................................................................................107FMERCURYPOROSIMETRYDISTRIBUTIONS............................................113LISTOFREFERENCES.................................................................................................117BIOGRAPHICALSKETCH...........................................................................................122

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ixLISTOFTABLESTable page 1.1ReductionTemperaturesforResearchedMetalOxides.............................................112.1ComparisonofInitialRatesoftheUT-3ThermochemicalProcess..........................252.2PropertiesofCalcinedIronSolidReactantPellets....................................................273.1QualitativeReactionStudy.........................................................................................453.2OriginalMixingRatiosforModifiedChemicalFormulationProcedure...................495.1ParametersintheMainCategoriesShowninFigure5.1............................................705.2ResultsofQuantatativeChemicalCompositionTestingProcedures.........................775.3OptimumParameters..................................................................................................81A.1ChemicalPropertiesofVariousSolidandLiquidsUsedinthisProject...................91C.1ChemicalRatiosUsedinModifiedChemistry..........................................................95

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xLISTOFFIGURESFigure page 1.1Two-stepWater-SplittingOxidesReductionProcesses............................................112.1FlowSheetoftheSolarUT-3ThermochemicalProcess............................................132.2ConceptualIllustrationofWholePlant.......................................................................162.3IllustrativeDiagramoftheMASCOTPlant...............................................................172.4TimeHistoriesoftheRateofHydrogenProduction..................................................172.5Original(a)andNew(b)FlowSheetsoftheUT-3Process.......................................182.6EnergyBalanceoftheUT-3HydrogenPlant.............................................................192.7HistoryofTotalGasProductionbyCyclicOperation................................................202.8ThermalEfficiencyofUT-3HydrogenPlantHavingMembraneSeparation............212.9ProcessforPelletizingSolidReactants.......................................................................252.10RelationshipBetweenPoreVolumeandAdditiveGraphiteContentinPellet........262.11ProductionProcessofthePelletUsingCaandTiAlkoxide....................................282.12SolidConversionProfilesofBrominationandHydrolysisbyCyclicOperation.....292.13PoreSizeDistributionofUnreacted(u)andBrominated(b)PelletsMadefromtheOldMethodandtheNewAlkoxideMethod............................................................292.14FlowChartofaModifiedMethodforthePreparationofaPelletsUsingAlkoxideMethodwithaDispersionChain.............................................................................302.15ComparisonoftheSolidConversionProfilesofBrominationandHydrolysisBetweentheConventionalMethod(Alkoxide)andModifiedMethod...................312.16ComparisonBetweenComputedandObservedTimeHistoriesofBromination.....32

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xi2.17ChangeofPoreVolumeinCyclicOperation...........................................................322.18ChangeofPoreVolumeDuringBromination..........................................................333.1ProductionProcessofthePelletUsingCaandTiAlkoxide.....................................453.2ThreeMouthedFlaskonStirringHeater....................................................................483.3FlowDiagramofProcedureOutlinedbyAiharaetal...............................................503.4HandPumpedUni-axialHydraulicPressforPelletProduction.................................543.5PelletMoldAssembly.................................................................................................543.6PelletMoldingAssemblyParts...................................................................................553.7FurnaceUsedforSinteringProcess............................................................................603.8HeatingSchemesforPellets......................................................................................604.1TypicalBETIsotherm.................................................................................................634.2SchematicRepresentationofAssumedDesorptionMechanismShowingThreeDifferentPoresandDemonstatingtheThinningofthePhysicallyAdsorbedLayerOvertheFirstThreeDecrements.............................................................................645.1FlowDiagramIndicatingHowCharacteristicswereUsedasFeedbacktoModifytheParameterstoArriveattheFinalProcedures..........................................................705.2SpecificCumulativeMicroporeVolumevs.MaximumSinteringTemperature........715.3RamanShiftSpectraofAnataseandRutileTiO2andTwoRepresentativePelletsMadeUsingtheOriginalChemistry........................................................................725.4VisualFlowDiagramofHowCharacteristicswereUsedasFeedbacktoModifytheParametersUsingtheModifiedChemistry..............................................................735.5ComparisonofCumulativeandDifferentialSpecificPoreVolumeDistributionforNewPelletsCompressedat0.25and0.5MetricTons............................................745.6RamanShiftSpectraforCaTiO3andTwoSamplePellets........................................765.7X-rayDiffractionDatawithPeaksVerifyingthePresenceofBothCalciumOxideandCalciumTitanate...............................................................................................78

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xii5.8ComparisonofMicroporeandMacroporeVolumeofPelletsMadewithRatiosofDifferentCalciumtoTitaniumRatioswithUT-3PorosityResults.......................795.9ComparisonofCumulativeandDifferentialSpecificPoreVolumeDistributionforNewPelletsSinteredatDifferentTemperatures.....................................................81B.1RamanModule...........................................................................................................92B.1InsideofFTRamanModule......................................................................................93D.1QuantachromeNOVA1200MachineforNitrogenAdsorptionwithSmallSampleCellandDewar......................................................................................................101D.3QuantachromeMercuryPorosimeterFillingApparatus.........................................105D.2QuantachromeMercuryPorosimeter.......................................................................105E.1RamanSpectraShowingthePelletsMadewithOriginalChemistryareMostlyComposedofAnataseandRutileTiO2..................................................................108E.2RamanSpectraShowingtheFluorescenceHidingtheCharacteristicPeaksofaSampleMadeUsingtheModifiedChemistry.......................................................109E.3RamanSpectraShowingtheExistenceofCaTiO3intheTwoPelletSamplesViatheMatchingPeakstoaStandard................................................................................110E.4FullRamanSpectraShowingtheExistenceofCaTiO3intheTwoPelletSamplesViatheMatchingPeakstoaStandard..........................................................................111E.5FullRamanSpectraShowingtheExistenceofCaTiO3intheTwoPelletSamplesViatheMatchingPeakstoaStandardTakenwiththeSameLaserIntensityontheSameScale.......................................................................................................................112F.1ComparisonofCumulativeandDifferentialSpecificPoreVolumeDistributionforNewPelletsMadewithDifferentCatoTiRatios.................................................114F.2ComparisonofCumulativeandDifferentialSpecificPoreVolumeDistributionforNewPelletsCompressedat0.25and0.5MetricTons..........................................115F.3ComparisonofCumulativeandDifferentialSpecificPoreVolumeDistributionforNewPelletsSinteredatDifferentTemperature.....................................................116

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xiiiLISTOFSYMBOLSChemicalElementsBrBromineCaCalciumCCarbonClChlorineFeIronHHydrogenIIodineMnManganeseNaSodiumOOxygenSSulfurSiSiliconTiTitaniumZnZincZrZirconiumCalciumCompoundsCaBr2CalciumBromideCaCO3CalciumCarbonateCa(OH)2CalciumHydroxide

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xivCaOCalciumOxideCaTiO3CalciumTitanateOtherChemistrySymbols+Positivepartialcharge-Negativepartialchargee-ElectronMMetalAtommStoichiometricsymbolnStoichiometricsymbolROrganicmoleculexStoichiometricsymbolyStoichiometricsymbolOtherSymbolsMercurysurfacetension[degrees]Mercurycontactangle[dyne/cm]CVConcentrationofvacantsitesonreactionsurface[mol/L]CN2-SConcentrationofsiteswithnitrogenadsorbed[mol/L]CsubscriptConcentration[mol/L]HH2PowerofhydrogenproducedbasedonHHV[MW]HHeHeatinputfromhelium[MW]HRHeatrecovered[MW]HXHeatexchangerIntRelativeintensityoflight[counts]

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xvkAAdsorptionratecoefficient[1/(psia*s)]KAEquilibriumadsorptionconstant[1/psia]MTMetrictonsPPressure[psia]PcPowerconsumed[MW]PoAmbientpressure[psia]PN2Pressureofnitrogen[psia]r3sRateofreaction3[mol/(L*s)]rADRateofadsorption[mol/(L*s)]RUniversalgasconstant[J/(gmol*K)]R1-R4Reactors1through4respectivelyS1-S2Separators1and2TTemperature[KorC]XConversion

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xviAbstractofThesisPresentedtotheGraduateSchooloftheUniversityofFloridainPartialFulfillmentoftheRequirementsfortheDegreeofMasterofScienceDEVELOPMENTOFCALCIUMOXIDESOLIDREACTANTFORTHEUT-3THERMOCHEMICALCYCLETOPRODUCEHYDROGENFROMWATERByBenjaminGrantHettingerDecember2005Chair:D.YogiGoswamiMajorDepartment:Mechanical and Aerospace EngineeringHydrogenmaybetheanswertomeetingtheworldsenergydemandasitincreasesandthefossilfuelsourcesrunout.TheUniversityofTokyo#3(UT-3)thermochemicalcycleisbeingresearchedasameansofproducinghydrogenfromwater.InordertomaketheUT-3thermochemicalcycleeconomicallyfeasible,theoperatingtemperaturesforthereactionsmustbereduced.Inordertostudythiscycle,thesolidreactantmustbeinaformthatwillallowthereactionstotakeplaceefficiently.AproceduretomakethesolidreactantfortheUT-3thermochemicalcyclehasbeendevelopedusingoutlinesfrompreviousresearchers.Theprocedureincludeschemicalprocedurestomaketheprecursors,dryingandpreheating,molding,andsinteringprocedures.Sol-gelchemistrywasusedtocreatetheparticulateprecursorsforthepellets.Theliquorresultantfromthechemistryprocedurewasdriedviaevaporationandthenpreheatedto430Ctoeliminatevolatiles.Theresultantpowderwasmoldedintopellets

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xviiusingacompressionmoldwhichhadbeenfabricated.ThepelletswerethensinteredtotemperaturesabovethehighestoperationtemperatureoftheUT-3cycle,760Cinordertostrengthenthepellets.Thecharacteristicsofthefabricatedpelletswereusedtogaugethesuccessoftheprocessandmodifyitasnecessarytoyieldbettercharacteristics.Thecharacteristicsofthepelletswhichwereusedtoevaluatetheprocedureweretheporosity,thecomposition,andthestrength.Theporositywasevaluatedbymercuryporosimetryandnitrogenadsorption.ThecompositionwasdeterminedqualitativelybyRamanspectroscopyandX-raydiffractionandquantitativelybyachemicalprocedure.Thestrengthwasevaluatedqualitatively.Basedonthesecharacteristicsanumberofchangesweremadetotheprocedureincludinganewchemicalprocedure,aredesignedmoldingassembly,andtheadditionofapreheatingstep.Correlationswerealsomadebetweencertaincharacteristicsandproceduralparameters.Onecorrelationshowedthattherewasanincreaseinstrengthwithsinteringtemperaturebutadecreaseinbothmacroandmicroporosity.Anothercorrelationshowedthatthestrengthofthepelletsdecreasedwithanincreaseintheratioofcalciumtotitaniumusedinthepellets.Thoughthesepelletsseemtohaveacceptablecharacteristics,morecharacteristicsincludingreactivityanddegradationneedtobestudied.Thesepelletsmaynotholdupstructurallyormaynotreactaswellastheymust.Furtherstudyneedstobedonetotrulydeterminethesuccessofthisprocess.Moreimportantly,thepelletsarejustthefirststeptowardstudyingtheUT-3thermochemicalcycle.

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1CHAPTER1INTRODUCTIONTheworldenergyconsumptionisrisingasmoreandmorecountriesbecomeindustrialized.Currentlythemostabundantlyusedsourcesofenergyarefossilfuels.These,however,arelimitedandmostprojectionsshowthattheproductionofoilwillnotmeettheneedwithinthenext10to25years.Thispresentsamajorproblemtoenergyconsumersaroundtheworldbutespeciallyfortransportationwhereoilisalmostthesoleenergysource.LookingaheadtheUnitedStatesisseekingthesolutioninhydrogenpoweredtransportation.TheU.S.governmentalongwithautomobilemanufacturersispushingresearcherstoinvestigatehydrogentomeetthisupcomingneed.Hydrogenhasbeenshowntobe40to50%efficientinfuelcellsandisenvironmentallyfriendlyproducingsteamasitsonlyby-product.Therearemanyproblemsthatmustbesolvedinordertomakethehydrogeneconomyfeasible.Alargeamountofresearchisbeingconductedtoinvestigatehydrogenproduction,fuelcells,storage,safety,andinfrastructure.Thisresearchfocusesonasmallbutimportantaspectofoneofthepotentialhydrogenproductionprocesses.Inthischapteranoverviewofthepresentmethodsforhydrogenproductionispresentedanddiscussed.CurrentHydrogenProductionMethodsThereareanumberofmethodsthatcanbeusedtoproducehydrogen.Thesemethodsincludesteammethanereformation(SMR),partialoxidationoffuels(POX)

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2coalandbiomassgasification,electrolysis,thermaldecomposition,thermochemicalprocesses,biological,andotherprocesses.Someofthesehavebeenfoundtobeimpractical,suchas,thermaldecomposition.Othersareestablishedmeansofhydrogenproductionandstillothersarecurrentlybeinginvestigatedandmaybeviableoptionsinthefuture.Ideallyaprocessissoughtthatisacosteffectiveandenergyefficientmeanstoproducehydrogenusingarenewableenergysource.Thiswouldallowutilizationofallthebenefitsofhydrogenasafuel.FossilFuelsThemostcosteffectivewaytoproducehydrogenistouseoneofthefossilfuelprocesses.Thoughtheseprocessesareefficientandcosteffective,theyalsoeliminateonofthemajoradvantagesofhydrogen.ThegreenhousegasCO2isstillbeingproducedifhydrogenisproducedinthismanner.Though,biomassisnotconsideredafossilfuelithasbeenincludedwithcoalgasificationbecauseofthesimilarityintheprocesses.Itisconsideredacarbonneutralmeansofhydrogenproduction.Alsothereasonhydrogenisbeingresearchedasafuelsourceisbecauseofthedepletingfossilfuelsources.SteammethanereformationSteammethanereformation(SMR)hasmanybenefitsandisthemosteconomicalmethodofproducinghydrogennow.Itisaprocessinwhichsteamandmethanearecombinedathightemperatures(700Cto925C)usingacatalyst.Asulfurseparationstepisneededsothatthecatalystwillnotbedestroyed.Afterthefirstreactionanequilibriumshiftreactionisaddedtoproducemoreoxygeninthecycle.Thetotalprocessresultis96-98%purehydrogenwithanefficiencyof65-75%(Goswamietal.,2003).Theheatissuppliedbyburningfossilfuels.Therearetwodrawbackstothismethod.Firstthemethodisnotcleanorgreen.Itproducesthegreenhousegas,CO-

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32.Seconditreliesonthelimitedamountofmethaneontheearth.AsthesupplydwindlesthefeedstockcostwillriseandmakeSMRlesseconomicalthanotherprocesses.ThechemicalschemeforSMRcanbeseenbelowinEquations1.1and1.2(CoxandWilliamson,1977-1979).CnHmnH2OnCO2nm2 H 2 (1.1)COH2OCO2H2 (1.2)PartialoxidationmethodThenextmostpopularmethodofhydrogenproductionispartialoxidationofheavyhydrocarbons(POX).ThismethodisverysimilartoSMRwiththeadditionofastep.Inthisadditionalstepheavyhydrocarbonsarepartiallyburnedwithpureoxygenandwater.Simultaneously,theheavyhydrocarbonsarebrokendownintolesscomplexhydrocarbonssuchasmethanewhichisreactedwithsteaminasimilarmannerasinSMR.TheresultingproductsareCO,CO2,H2O,H2.Afteradesulphurizationsteptheshiftreactionisagainusedtoproducemorehydrogen.POXproduceshydrogenwithapurityof96-98%andanefficiencyofabout50%(Goswamietal.,2003).ThesameproblemsexistwithPOXasdidwithSMR.TheadditionalstepofoxygenseparationincreasesthecostofthisprocesscomparedtoSMR.CnHmn2 O2nCOm2 H2 Heat (1.3)CnHmnH2OHeatnCO2nm2 H 2 (1.4)COH2OCO2H2Heat (1.5)CoalandbiomassgasificationCoalandbiomassgasificationareverysimilartoPOXwiththedifferencesofahighertemperaturerange(1100C-1300C),higherpressures,andthereisverylittle

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4oxygenpresent.ThehighcarboncontentofcoalandbiomassisconvertedtoCO2,H2,andCO.AfteradesulphurizationsteptheshiftreactionisagainusedtoproducemoreH2.Purityofhydrogenofupto97%hasbeenobtainedusingcoalgasification(Goswamietal.,2003).Coalisthemostabundantfuelonearthandsupplieswillprobablynotbeaconcernforacenturyfromnow.Likethosementionedbefore,thisprocessproducesthegreenhousegas,CO2.Usingbiomassasthefuelotherbenefitsandproblemsexist.Benefitsincludevaluablebyproductssuchasammonia,betterpollutioncontrol,andloweroperatingcosts.BiomassisalsoconsideredacarbonneutralfuelbecausetheCO2wouldbeproducedthroughnaturaldecompositionanyway.Theproblemslieintransportingthesolidfuelanddisposingofthelargequantitieswasteashthatareproduced.2C+O22CO(1.6)C+H2OCO+H2(1.7)C+CO22CO(1.8)AlltheseprocessesbasedonfossilfuelsproduceCO2.Presentlytheyarethemostcosteffectivewaystoproducehydrogen.Themainbenefitofhydrogenasafuelisthatitdoesnotproduceanyharmfulbyproductswhenusedtomakeenergy.IfitisproducedinamannerinwhichCO2iscreatedthisbenefitisessentiallyeliminated.Alternativemethodsmustbeusedifthisbenefitiswanted.ElectrolysisElectrolysisofwateristhenextmostcommonlyusedmeanstoproducehydrogen.Inelectrolysisavoltageissuppliedsothatelectricityflowsthroughamediumandionsareconductedacrossamembrane.H2isproducedbycombingH+ionsandtwoelectronsatthecathodeasshowninEquation1.9.WaterissplitattheanodesothatO2

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5isproducedalongwithH+ionsandelectronsasseeninEquation1.10(CoxandWilliamson,1977-1979)H2O.5O2+2H++2e-Anode(1.9)2H++2e-H2Cathode(1.10)Electrolysishasbeenresearchedextensivelyandsomeideaspresentlybeingconsideredaretheelectrolysisofseawaterandefficiencyincreasewithtemperaturevariance.Electrolysishasbeenseentobe94%efficientbasedontheelectricalpowerinputtothesystem(Goswamietal.,2003).Thiselectricityhowevercomesfromanothersource.Solarproducedelectricityisaverygoodsourcetouseforelectrolysis.Almostalltheelectricityproducedbysolarmeanscanbeusedtomakehydrogen.Thiscreatesacleanwaytoproducehydrogenandcaneliminateanyfossilfuelsfromtheprocess.ThermalDecompositionofWaterWhenwaterisheatedtoveryhightemperaturessomeofthesteamdecomposestoO2,H2,OH,O,andH.Atfirstglancethisprocessseemsverysimple,butithasmanyproblems.Alargeamountofenergyhastobesuppliedtoheatwatertotheneededtemperatures.Thesteamdoesnotevenfullydissociateuntilatemperatureabove4000Kisreached.Themixtureofdissociatedgasesisalsohighlyexplosivewhichcreatesaveryseriousdanger.Findingcontainersthatcanwithstandthetemperaturesneededfortheoperationalsopresentsaproblem.Hightemperaturegasseparationisalsohardtodo.Quenchingcanbedonebuttheheatlostduringtheprocesscannotberecoveredandmakestheprocesstoocostlytooperate.Only2.1%efficiencyhasbeenrecordedusingthethermaldecompositionofwatertoproducehydrogenandonlya40%theoretical

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6efficientlyhasbeencalculated(Goswamietal.,2003).Obviously,thisprocessisnotfeasibleunlesssolutionsarefoundtotheseproblems.ThermochemicalProcessesInthermochemicalprocesseswaterisinputalongwithheatandoxygenandhydrogenareproduced.Theoverallresultthenisthesameasthatofthermaldecomposition.Theseprocessesaremuchdifferent,however,andmuchmorepractical.Theprocesseshavebeentheoreticallymodeledtobeupto50%efficientdwarfingthe2.1%efficiencyofthethermaldecompositionofwater(Sakuraietal.1996).Muchlowertemperaturescanalsobeusedandhydrogenandoxygencanbeproducedindifferentstepseliminatinganexplosivemixtureofgases.Eachthermochemicalprocesshoweverhasitsownproblemsthatmustbeconsideredtomaketheprocessfeasible.Insidethisblackboxsystemaseriesofheatdrivenchemicalreactionsareusedtoproducehydrogenandoxygen.Therearethousandsofproposedprocessesbutonlyafewwhichhavebeenstudiedextensivelyandevenfewerthatholdpromiseinlargescaleimplementation.Someoftheseprocessesarediscussedlaterinthischapter.PhotoelectricalandPhotochemicalHydrogenProductionPhotoelectricalsystemscoupleasolarvoltaiccellwithelectrolysis.Aphotoanodeabsorbssunlightcreatingacurrenttoflowandelectrolysistooccur.Hybridsofthissystemhavereportedefficienciesofupto18%(Goswamietal.,2003).Inphotochemicalsystemssemiconductorsarepairedwithphotosensitiveorganicparticles.Whenlighthitsthephotosensitiveparticleselectronsareexcitedandaredirectlyusedtocarryoutthereductionandoxidationreactionstocreatehydrogen.Thereareproblemsinthecatalystandphotosensitivematerialdegrading,backreactions,andtheseparationofhydrogenandoxygen.Photochemicalsystemshaveyettoreach10%efficiency

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7(Goswamietal.,2003).Moreinvestigationmustbeconductedtoevaluatethefeasibilityofthesehydrogenproductionmethods.BiologicalHydrogenProductionTherearetwogeneralbiologicalmethodsthatareusedtoproducehydrogen.Thefirstisthefermentationofbacteria.Inthisprocessorganicsubstancesareconvertedtooxygenandhydrogenwithoutsunlightoroxygen.Thetheoreticalefficiencyforthisprocessisonly33%(Goswamietal.,2003).Treatmentofthepollutedprocesswatermayalsobeaproblemwhichshouldbeaddressedwhenconsideringthisprocess.Thesecondmethodiscalledbiophotolysis.Inthisprocessmicro-algae-cynobacteriaandgreenalgaeareexposedtosunlightandwater.Throughorganicprocessestheyproducehydrogenandoxygen.Therearetwotypesofbacteria,nitrogenaseandhydrogenase.ThefirstofthetwousesATPmoleculesandcovertsthemtoADPmoleculesreleasingH+ionsintheprocesswhichformhydrogen.Hydrogenaseproduceshydrogenbybreakingdowncarbohydratesinaphotosynthesissystem.Bothwilldieinthepresenceofasmallamountofoxygen(Goswamietal.,2003).ThermochemicalCyclesTherearethousandsofthermochemicalprocesses.Theprocessesvarywidelyinmanydifferentaspectsthoughsomeareverysimilar.Manyoftheprocessesareslightmodificationsofapreviouscycle,includingasubstitutereactionorreactionsand/oranimposedvoltage.Processeswithimposedvoltagesareknownashybridthermochemicalcycles.IspraMarkProcessesThefirstthoroughlyresearchedprocessistheIspraMarkIprocessshownbelow.Ascanbeseenmercuryisusedinthisprocess.Mercuryisknowntobeaverytoxic

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8elementandresearchonthisprocesswasdiscontinuedbecauseonalargerscaleusetheprocesswouldbetoomuchofasafetyriskforconsideration.Theprocesswasimportant,however,asitwasaharbingeroftheexplorationofthermochemicalcycles.Itwasthefirstprocessdemonstratedtogivereasonableamountofhydrogenatanacceptableefficiency.OtherprocessesfollowedtheIspraMarkIandtherearenow17IspraMarkprocessessomeofwhichhavedifferentsub-processes.TheseriesofIspraMarkprocessesaresomeofthemostpromisingthermochemicalprocesses.IspraMarkICaBr2+2H2OCa(OH)2+2HBr(730C)(1.12)2HBr+HgHgBr2+H2(250C)(1.13)HgBr2+Ca(OH)2CaBr2+HgO+H2O(200C)(1.14)HgOHg+.5O2(600C)(1.15)Muchworkhasbeendoneinexploringthepossibilityofusingiron-chlorideinprocesses.IspraMarkprocesses7,7A,7B,9,14,and15containiron-chloride.ProblemsintheseprocesseshavebeenfoundandgenerallystemfromeitherthethermaldecompositionofFeCl3(Eq.1.17)orthehydrolysisofFeCl2(Eq.1.18).Muchresearchhasbeenconductedtoeliminatetheseproblemsbutnoviablesolutionhasbeenfound.Theiron-chloridefamilyofreactionswasdeemeduneconomicalandresearchhasbeenfocusedelsewhere.IspraMark7Bcanbeseenbelow.IspraMark7B2Fe2O3+6Cl24FeCl3+3O2(1000C)(1.16)2FeCl32FeCl2+Cl2(420C)(1.17)3FeCl2+4H2OFe3O4+6HCl+H2(650C)(1.18)Fe3O4+O26Fe2O3(350C)(1.19)

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9Anotherfocusareaofresearchwasthesulfurfamilyprocesses,mostlyconcerningthedecompositionofsulfuricacid.TheIspraMark4,10,11,12,13,16and17processesallusesulfur,buttheonesthatfocusonthedecompositionofsulfuricacidare11,13,16,and17.Eachprocessstartswiththethermaldecompositionofsulfuricacidbutthereare4differentschemestofinishtherespectiveprocesses,threeofwhichareshownbelow.DecompositionofSulfuricAcidH2SO42SO2+2H2O+O2(1.20)IspraMark11(alsoknownasWestinghouse)SO2+2H2O+elecH2SO4+H2(1.21)IspraMark132H2O+Br2+SO2H2SO4+2HBr(1.22)2HBr+elecBr2+H2(1.23)IspraMark16(alsoknownastheGeneralAtomicProcessandthesulfur-iodineprocess)2H2O+I2+SO2H2SO4+2HI(1.24)2HII2+H2(1.25)TheIspraMark16processisalsoknownastheGeneralAtomic(GA)processbecauseofGAsextensiveworkonit.Itshowsmuchpotentialandisoneofthemostresearchedprocesses.Sulfur-IodineorMark16orGAProcessI2+SO2+H2O2HI+H2SO4(100C)(1.26)2HIH2+I2(420C)(1.27)H2SO4H20+SO2+.5O2(850C)(1.28)TheGAprocesshasmanydesirableaspects.Threereactionsareusedatrelativelylowthermochemicalprocesstemperatures.Thereactionscanalsobearranged

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10tocreateacontinuousprocess.Manypeoplehavestudiedthisreactionandithasbeenwellresearched.Theoreticalefficiencieshavebeenpredictedtobeapproximately50%.Thereareexpensiveseparationandpurificationstepsthatneededtobeconsidered.Thisprocessalsouseshighlyacidicchemicals.Inadditiontherehavebeenproblemswithhydriodicaciddecomposition.At700Kthereisonlya25%dissociationwhichcannotbegreatlyincreasedwithtemperature.This,therefore,makesitnecessaryfortheproductstoberecirculatedcreatingthermallosses.Anotherfactorthatmustbeconsideredisthepossibilityofsidereactionswhichcanformsulfurandhydrogensulfide.Despitetheseproblems,thisprocessisbeingstudiedatanumberofplacesandhasarguablythemostpotentialofthermochemicalprocessestobeusedtoproducehydrogen(Sakuraietal.,1999,2000)MetalOxidesMxOy=xM+y/2O2(HighTemperaturereductionreaction)(1.29)xM+yH2O=MxOy+yH2(LowTemperaturesoxidationreaction)(1.30)Anotherlargeareaofresearchwithinthermochemicalprocessesisbeingconductedonmetaloxidereduction-oxidation(redox)processes.Metalsarereducedwithheatcreatingapuremetalandreleasingoxygen.Themetalisoxidizedwithwatertoformametaloxideonceagain.Themetalstealstheoxygenfromthewatersothathydrogenisreleased.Thereareanumberofmetalsandalloysbeingconsideredatthistime.Thesimplicityoftheprocessesseemsappealing,havingonly2reactions.Mostoftheoxidizingreactionsproceedwithoutproblem.Anundesirablerequirementoftheseprocessesisthatthereductionreactionoccursatveryhightemperatures.Muchofthe

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11workbeingdoneistofindanalloythatwillsignificantlylowerthetemperatureofthereductionreaction.Oneofthemostpromisingisthezincoxidereaction.Reportedconversionefficiencieshavebeenashighas50%(Weidenkaffetal.,2000).Thetemperatureforthereductionreactionhoweveris2300K.TheprocessisdepictedbelowinFigure1.SolarReactor1stStep@2300KZnO-->Zn(g)+12O2WaterSplittingReactor2ndStep@700KZn+H2O-->ZnO+H2ZnO H2 ZnOH2 12O2 ConcentratedSolarRadiation Figure1.1Two-StepWater-SplittingOxidesReductionProcesses(Weidenkaffetal.,1999)Othermetalsandalloysconsideredarelistedbelowwiththeirreductiontemperature.Someofthetemperatureshavebeenreportedoverarangeoftemperatures.Forsimplicity,onevaluewaschosenandtheactuallytemperatureswillvarysomewhatbasedontheexperimentaldesign.TheTableisjusttoshowtypicaltemperaturevaluesforthermochemicalmetaloxideprocesses.Table1.1:ReductionTemperaturesforResearchedMetalOxides MetalorAlloy [K] [C] References ZnO 20001727Weidenkaffetal.,2000&Hauteretal.,1999 Mn2O3 18351562Meieretal.,1996&SturzeneggerandNuesh,1998 Fe3O4 23002027Steinfeldetal.,1999 MnFe2O4 12731000Ehrensbergeretal.,1995 Na3(MnFe2)O6 1073 800 Kanekoetal.,2001,2002

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12MiscellaneousProcessesThereareotherprocessesthathavebeenresearchedbydifferentgroups.Mostgroupsarefoundeitheratuniversitiesorscientificlabsaroundtheworld.OnegroupattheUniversityofTokyodevelopedoneofthemostpromisingprocesses.Theyhavedoneextensiveresearchontheprocessandup-scaledtheirlaboratoryscalemodel.Itispredictedtobethefirstthermochemicalprocessthatwillactuallybeusedforlargescalehydrogenproduction.ThisprocessisknowastheUT-3processandwillbediscussedinmoredetailinthenextchapter.AnotherprocessthatmighthavepotentialistheJulichCenterEOSshownbelow.2Fe3O4+6FeSO46Fe2O3+6SO2+O2(800C)(1.31)3FeO+H2OFe3O4+H2(700C)(1.32)Fe2O3+SO2FeO+FeSO4(200C)(1.33)Itisinthebeginningstagesofresearchandhasmanydesirableattributes.Reactantsinthiscyclearenotcorrosive.Besidesoxygenandhydrogen,theonlyelementsusedaresulfurandironwhichareveryabundantontheearth.Earlytestingshowsthereactionsgoaswritten.Notmuchcurrentresearchisbeingconductedonthisprocess,however.Thismaybeduetoothersignificantproblemsencountered(Brownetal.,2002).

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13CHAPTER2THEUT-3THERMOCHEMICALPROCESSTheUniversityofTokyo#3thermochemical(UT-3)processwasproposedin1978byKameyamaandYoshidaatthe2ndWorldEnergyConference(KameyamaandYoshida,1978).AUT-3cycleiscomposedofaseriesoffourthermochemicalreactionswhichareshownbelow.Theoperatingtemperaturesarerelativelylowerthanthosefoundinotherthermochemicalcycles,thehighestbeing760C.Whenthereactionsproceedinthecorrectorderallthesolidreactantsareregenerated,exceptwaterwhichissplitintohydrogenandoxygenandseparatedfromthesystem.TheflowschematicoftheUT-3ThermochemicalprocessisshowninFigure2.1belowandthereactionsareenumeratedbelow: Figure2.1FlowSheetoftheSolarUT-3ThermochemicalProcess(Sakaraietal.,1996)TheUT-3Systemstartswithwaterbeingpumpedintothesystem<16>,heatedintosteaminHX01,andpumpedintothereactorR1wherereaction(2.1)occurwith

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14CaBr2togenerateHBr.Thisreactionisreportedtotakeonehourtoreachequilibrium.Surplussteamalongwithothergaseousproducts(primarilyHBr)isroutedtoreactorR4wherereaction(2.4)takesplacewiththereleaseofH2andadditionalHBr.(ReactorR1,760C)CaBr2+H2O(g)CaO+HBr(g)(2.1)(ReactorR2,570C)CaO+Br2(g)CaBr+.5O2(g)(2.2)(ReactorR3,220C)Fe3O4+8HBr(g)3FeBr2+4H20(g)+Br2(g)(2.3)(ReactorR4,560C)FeBr2+4H2O(g)Fe3O4+6HBr(g)+H2(g)(2.4)HydrogenisseparatedfromthemainprocessstreamatS1.ThebalanceflowprimarilycontainingHBrreactswithFe3O4inreactorR3toformBr2asshowninthereaction(2.3).Br2thenreactswithCaOinreactorR2toreleaseO2asshowninthereaction(2.2).O2isseparatedinS2andthebalanceofthestreamflowswiththemake-upwater,at<16>,backtoreactor1completingthecycle.Theprominentfeaturesoftheprocesspatharelistedbelow.1.Onlywaterisfedthroughthestream<16>whichisconsumedandsplitintoH2andO2.2.ReactorsR1andR4(hydrolysisreactors)produceH2andReactorsR1andR2andR3(brominationreactors)produceO2.3.TheproductsofreactorsR1andR4arereactantsinthereactorsR2andR3respectively.Asreactionequilibriumisreachedinthereactors,theflowdirectionisreversed,wherereactorsR2andR3nowfunctionasthehydrolysisreactors(producinghydrogen)andreactorsR1andR4serveasthebrominationreactors(producingO2).Thisswitchoverapproachcanberepeatedmultipletimesforcontinuousoperation.HistoryofResearchontheUT-3ThermochemicalProcessThroughtheyearsthereactionsandprocesshavebeenstudiedextensivelybygroupsinJapan.TheUT-3processmayhavepotentialasameanstocommerciallyproducehydrogeninacarbonfreeandenergyefficientmanner.However,inorderto

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15evaluatethispotential,anumberofdifferentaspectsoftheUT-3processhavetobeinvestigated.Fordiscussiontheseaspectsarecategorizedintoprocessandsimulationstudies,membraneandseparationtechniques,ironsolidreactants,andcalciumsolidreactants.ProcessandSimulationStudiesThefirstinvestigation(KameyamaandYoshida,1978)examinedtheGibbsfreeenergyofeachofthereactionsintheUT-3process.Anexperimentalsetupwasreportedbutnosignificantsystemstudywasmade.In1981,aconceptualdesignofalargescaleUT-3thermochemicalprocesshydrogenproductionplanttobecoupledwithahightemperaturenuclearpowerplantwasgiven(KameyamaandYoshida,1981).Thefacilitywouldincludethreemainsections(Figure2.2).Thefirsttwoconsistingofareactiontowerforthecalciumreactantsandanotherfortheironreactants.Thethirdsectionwouldbeatowerforheatexchangerstobringhightemperatureheattothereactorsandrecoverwasteheatfromotherreactors.Thedesignincludesaprovisionforusingsolidreactantsintheformofhoneycomb-shapedtubeswithinertmaterialsasbinders.Thehoneycomb-shapedsolidreactantswouldbeputintoafixedbedreactor.Thereactionscanoccuralonghoneycombchannelsisolatingtheprocessstreamfromthereactorwalls.Thusthiswouldeliminatetheneedforexpensivematerialsofconstructionsuchastitanium.Inthispaperasimulationwasalsodonetodeterminethereactionzoneaswellasinvestigateheatexchangerdesign.ResultsfromtheperformanceoftheMASCOT(ModelApparatusforStudyingCyclicOperationinTokyo)benchscaleUT-3plantwerereportedin1984(Nakayamaetal.,1984).MostofthepaperfocusedontheexperimentalsetupfortheMASCOTplant

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16(Figure2.3).Theplantwasdesignedtoproduce3normallitersofH2perhour.Itwasrunfor2cycleswithapeakperformanceof2normallitersperhour(Figure2.4). Figure2.2ConceptualIllustrationofWholePlant(KameyamaandYoshida,1981)AchangeintheprocessflowwassubsequentlyintroducedsothattheHBrfromreaction1wouldnothavetobeseparatedfromsurplusH2Obeforeenteringreaction4(Kameyamaetal.,1989).RathertheHBriscarriedthroughreactor4andproceedstoreactor3.Figure2.5showstheoriginal(a)andthemodifiedschemes(b).Themodifiedschemereducestheflowcomplexityfoundintheoriginalprocess.

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17 Figure2.3IllustrativeDiagramoftheMASCOTPlant(Nakayamaetal.,1984) Figure2.4TimeHistoriesoftheRateofHydrogenProduction(Nakayamaetal.,1984)

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18 Figure2.5Original(a)andNew(b)FlowSheetsoftheUT-3Process(Kameyamaetal.,1989)In1989anin-depthefficiencystudywasdoneonthewholecycle(Aochietal.,1989).Thestudyprojectedgreaterthan40%thermalefficiencyifpowergenerationfromwasteheatwas25%orgreater.Anenergybalancewasalsodoneshowingthebreakdownoftheenergyusageassumedtoobtainthisefficiency(Figure2.6).THH2HHeHRPc860.6sp (2.5)HH2istheenergyperunittimeofthehydrogenproducedintheplant,atthehigherheatingvalueinMW.HHeistheInputheattothechemicalprocessfromthehightemperaturegasreactor(HTGR)plantbyheliumgasinMW.HRistheheatrecoveredinMW.PCisthepowerconsumedwithintheplantinMWand860.6isaconversionSPisthepowergenerationefficiency,whichmeanstheefficiencyofthe

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19TistheoveralltotalefficiencyasdefinedbyAochietal. Figure2.6EnergyBalanceoftheUT-3HydrogenPlant(Aochi,etal.1989)TheMASCOTwasoperatedwiththenewflowschemefor11cyclescontinuously(Sakuraietal.,1992).Itwasfoundthattherewasclosetoa2to1ratiobetweenhydrogenandoxygenproduced.Thesystemappearedtooperatesteadilythoughslightfluxuationsexisted.Theyieldseemstobelowerinthisexperimentthanthatreportedin1984byNakayamaetal.butthecyclicruntimeisnotgivenforthisexperiment.Theruntimefortheothercycleswasapproximately2hoursthough,soitwouldseemthattheruntimewouldbeatleast1hourandthattheyieldwouldbearound

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201to2literspercycle.Itisthoughtthatthenewflowschemewouldnotaffectthehydrogenoutputsodrastically.Thereasonforthisdiscrepancyisunknown,thoughcycletimesofonlyabout10to20minuteswouldreconcilethetwosetsofdata. Figure2.7HistoryofTotalGasProductionbyCyclicOperation(Sakuraietal.,1992)Mostoftheresearchfrom1996onwardfocusedonsimulationsoftheUT-3Process.In1996Sakurai,Bilgenetal.published2papers.Thefirstdiscussesthepossibilityofusingasolarconcentratortosupplytheheatforthecycle.Theyconcludethatitwillbefeasibletooperatewithathermalstorageunitand24houroperation.TheseconddiscussesanadiabaticmodeloftheUT-3Cycle.Acomputersimulationisrunandfirstandsecondlawefficienciesarefoundtobe48.9%and53.2%respectively.ThenextyearatechnicalevaluationofanindustrialscaleplantfortheUT-3thermochemicalcycleisreportedbyTadokoroetal.(1997).Themainfocusofthepaperwastheimprovementintheoverallthermalefficiencywithmembraneseparation.Figure2.8illustratestheirpredictedefficiencies.Theyconcludedthattheuseofamembranefor

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21separationwillincreaseefficiencyandthereforeimprovetheeconomicsofhydrogenproductionbytheUT-3thermochemicalprocess. Figure2.8ThermalEfficiencyofUT-3HydrogenPlantHavingMembraneSeparation(HighHeatingValueBasis)(Tadokoroetal.,1997)After1997thereisnotmuchpublishedontheUT-3process.Teoetal.(2005)carriedoutananalysisontheUT-3processefficiency.Theiranalysisincludedpracticalconsiderationsofequipmentefficiencies(compressors,heatexchangers),separationmembranesandassociatedpressureloses,incompleteconversionsforthereactions,lowtemperatureheat,andtheimpracticalityofisothermaloperationintheironreactors.

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22Theirvalueforprocessefficiencyfromsolarheatwaslessthan7%.Togivemorecredibilitytothispaper,inthepostscripttheauthorstelloffeedbackfromtheresearchanddevelopmentcommunitythatindicateditiswellknownthattheefficiencyoftheUT-3thermochemicalprocessismuchlowerthanclaimedbyoriginalresearchers.Theauthorsindicatedthatthishasnotbeenpublishedinapublicdomainuntilnow.Theyalsoindicatedthatotherthermochemicalprocessesshouldbeevaluatedinasimilarmannertoweighthequestions:Shouldworkbedoneontheseprocesses?Andifsowhichones?Membrane,SeparationTechniques,andMaterialsOneofthemostimportantfactorsaffectingtheenergyefficiencyoftheprocessistheseparationofhydrogenandoxygenfromtheprocessstream.Thehydrogenisproducedinareactionwithatemperatureof570C.Hydrogenhastobeseparatedfromstreamcontaininghydrogenbromideandnitrogenorsteam(usedinexcess).Separationcanbeaccomplished(ifnitrogenisnotused)bycondensationofwaterandhydrogenbromide.This,however,ishighlyenergyinefficientmeansofseparationsincethiscondensedstreamhastobereheatedbeforeitissenttothebrominationreactorR3(Figure2.1).Alternatively,researchhasfocusedondevelopinghightemperaturecorrosionresistanceceramicmembranestoseparatehydrogenfromtheothergases.Thishasalsoprovendifficultbecauseoftheincompatibilityofhydrogenbromidewithmostmembranematerial.Thelistofhydrogenbromidecompatiblematerialsisfurthershortenedduetothehightemperaturesatwhichdesiredseparationsshouldoccur.ThepressuredropacrossthemembranesishighandtheseparatedH2hastobecompressedwhichrequiredadditionalenergy.

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23Tomeettheseneedsazirconia-silicacompositewasstudiedfortheseparationofhydrogen(Ohyaetal.,1997,1994).Thestudyfoundthathydrogenbromideandsteamwereabletopermeatethemembranemuchmorethanthehydrogen.Thusthehydrogencouldbeseparatedintherejectstreamandthehydrogenbromideandwatercouldbeseparatedoutthroughthemembrane.Separationfactorsbetween6and36wereobtainedusingdifferentpressuregradientsandtemperaturesrangingfrom423K-773K(250C-500C).TheHBr-H2O-H2separationwasalsoinvestigatedbyMorookaetal.in1996.Theapproachusedan-aluminasupportwithasilicamembraneandwastestedupto400Cwitheffectiveresults.Thehydrogenbromidecouldnotpassthroughthemembraneandtheseparationfactorbetweenhydrogenandwaterwasover100.Thoughthesemembranesstilldonotfunctionatthereactiontemperatureof570Ctheyallowforamuchmoreenergyefficientseparationofhydrogen.Materialsforpipingandotherpartsalsoneedtobeconsidered.NotmanymaterialscanwithstandthecorrosivecomponentssuchasBr2andHBratsuchhightemperatures.Titaniumwouldworkbutthecostistoohightomakethesystemeconomicaltoproducehydrogen.CeramicmaterialsarealsobeingdevelopedforusewiththeUT-3cycle.SasakiandHirai(1994)coatedstainlesssteelwithTiC-SiCfilmusingvapordepositiontechniquesandtesteditinaBr2-O2-Arenvironmentupto800C.Thetemperaturewascycledbetween500Cand800C.Corrosionwasstillpresentbutgreatlyreduced.Anotherproposedplantoreducematerialsofconstructioncostistorunthesystemwithexcesssteamornitrogenoramixtureofthetwo.Thisiswhatiscurrently

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24doneintheUT-3process.Noreportsofcorrosionproblemsappearintheliterature,thoughitissuspectedthatcorrosionmayoccurovertime.SolidReactantsApelletformhasbeenchosentomeetthestrengthandreactivitydemandsofthecyclicUT-3processforboththeironandcalciumreactants.EveninthefirstproposaloftheUT-3processKameyamaandYoshida(1978)emphasizedtheimportanceofdevelopingdurablesolidreactants.Theirdevelopmentandimprovementsareoutlinedhere.IronreactantsIn1978KameyamaandYoshidatestedthreesupportsfortheironreactants.Thesesupportsincluded120micronglassbeads,Bentonite(atypeofclay),andKaolin(highqualityclayusedtomakechina).Thepelletsweremadeinto15mmspheres.ThebentonitesupportedmaterialseemedtohavethebestconversiontoFeBr2whichwasabout45%.In1981KameyamaandYoshidareportedontheirstudiesoftheironsolidreactantsandtheirchemistry.TheironoxidepelletsweremadebymixingFe3O4andsilicasol(Cataloid-S-OH),addingasaturatedsolutionofammoniumcarbonate,thendrying,molding,andcalcination.Itwasreportedthatreaction3wasfoundtobecomposedoftwostagesrepresentedbyFe3O4+2HBrFe2O3+FeBr2+H2O(2.6)Fe2O3+6HBr2FeBr2+3H2O+Br2(2.7)Takingintoconsiderationthemassandheattransferresistancesfromthegasfilm,productlayerandsurfacechemicalreactiontheseresearcherscameupwithtwoequationsforreactionratesfordifferenttemperatureregions.Thereactionratesusetheshrinking

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25coreandassumedtoprecedetopochemically.ThesereactionsareshownhereinEq.2.8andEq.2.9whereaisthesurfaceareaofthereactionincm2.r3s38.2aCFe3O4.00150 C HBr (210C-255C)(2.8)r3s1.78108exp13.0RT aCFe3O4.00150CHBr .5 (255C-300C)(2.9)AmoredetailedironpelletformulationprocedureisgivenbyYoshidaetal.(1990).Figure2.9showsanoutlineofthisformulationalongwiththatofthecontemporarycalciumpelletformulationprocedureofthattime.Thereactionratesofallfourreactionswerealsoevaluatedexperimentally.AtabulationoftheseratescanbeseeninTable2.1below. Figure2.9ProcessforPelletizingSolidReactants(Yoshidaetal.1990).Table2.1ComparisonofInitialRatesoftheUT-3ThermochemicalProcessYoshidaetal.(1990).

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26In1992anotherpaperwaspublishedontheprocedureofmakingtheironpellets(Amiretal.,1992).Thepaperhighlightstheuseofgraphitetoincreaseporositybymorethan5times.Specificporevolumewithnographitewas.06cc/gandwasincreasedto.35cc/gwhen20%byweightgraphiteisused.Figure2.10showsalinearrelationshipbetweenthetotalcumulativeporevolumeandthepercentofgraphiteadded Figure2.10RelationshipBetweenPoreVolumeandAdditiveGraphiteContentinPellet(Amiretal.,1992)In1993Amiretal.publishedresultscomparing8differentceramicsupportsfortheironreactants.Theanalysisincludedthechemicalcomposition,hardness,porosity,andreactivityofthepellets.ATableoftheresultscanbeseeninTable2.2below.Degradationofreactivityoccurredoveranumberofcycles.ItwasconcludedthatsomeFeBr2sublimesatthehightemperatureofthereactions.Thisreducestheironcontentandalsoplugstheporesasitleaves.Thereisalsoagglomerationofironoxideparticles

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27whichreducessurfaceareaanddamagesthestructureoftheporesbothofwhichhaveanadverseeffectonreactivity.Thisisthelaststudywhichfocusedontheironreactants.Table2.2PropertiesofCalcinedIronSolidReactantPellets(Amiretal.,1993) CalciumreactantsThereactionratesofreactions1and2werereportedin1989(Kameyamaetal.)andthenagainin1990(Yoshidaetal.,Table2.1onpreviouspage).Kameyamaetal.(1989)usedX-raymicroanalyzerandfoundthatafterthebrominationreactioncalciumbromidewasequallydistributedthroughoutthepelletconfirmingtheirpredictionofahomogenousreaction.Table2.1givethefindingsofYoshidaetal.(1990).TheformulationofthecalciumpelletswasfirstreportedbyYoshidaetal.(1990).Itisthoughtthatthisprocedurehadbeenusedforanumberofyearsbeforebutonlyreportedin1990.Figure2.9aboveoutlinesthisprocedure.Theprocessusesamixtureofcalciumcarbonateandtitaniumdioxidewithsomegraphite.Themixtureismadeintopelletsandheatedto1100CsothatthecalciumcarbonatelosesCO2leavingCaO,theneededsolidreactant(Eq.2.10).Atthistemperaturesomeofthecalciumoxidewillalsobondwiththetitaniumdioxideformcalciumtitanate(Eq.2.11).CaCO3CaO+CO2(2.10)CaO+TiO2CaTiO3(2.11)

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28MetalCaC2H5OHCa(OC2H5)2Ti(OC3H7)4GraphitePowderH2OPrecursors RefluxingHydrolysisFiltrationMoldingCalcinationCaOCaTiO3Pellet Figure2.11ProductionProcessofthePelletUsingCaandTiAlkoxide(Aiharaetal.,1990)Anewmethodforfabricationofcalciumpelletswasreportedin1990byAiharaetal.Thismethodusesalkoxidechemistrytocreatecalciumtitanateandcalciumoxide(Figure2.11).Pelletsweremadefromboththeoldandnewmethodsandtheirperformanceinthecyclewascompared.Thenewmethodhadamuchhigherreactionratewhichreducedthetimetomaximumconversion.ThiscanbeeseeninFigure2.12below.

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29 Figure2.12SolidConversionProfilesofBromination(left)andHydrolysis(right)byCyclicOperation(Aiharaetal.,1990)Inthenewpelletsthecalciumoxidewasdistributedinsmallerparticlesinamoreevenarrangement.Thisreducedporecloggingsignificantlyandthereforedecreasedtheconversiontimes.Figure2.13illustratesthereductioninporevolumeafteronerunfortheoldandnewmethodsrespectively. Figure2.13PoreSizeDistributionofUnreacted(u)andBrominated(b)PelletsMadefromtheOldMethod(Left)andtheNewAlkoxideMethod(Right)(Aiharaetal.,1990)In1992Sakuraietal.studiedtheratesofreactionwiththepelletsmadeusingalkoxidechemistry.Thereactionrateswereproportionaltofirstorderofboththebromideandcalciumoxideconcentrations.Itwasalsofoundthatbromination(Eq.2.2)

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30shouldtakeplaceabove590Ctopreventformationofbyproducts,thoughthesebyproductsarenotspecified.In1995Sakuraietal.reportedanothersignificantimprovementintheformationofthecalciumoxidepellets.AverysimilarapproachtoAiharaetal.wastakenbutadispersionchainofchemistrywasadded.Thesamealkoxidechemistrywasusedtocreatethecalciumtitanate.Thenanotherformulationwasaddedtomakeverysmallparticlesofcalciumoxide.ThisseparatedthesynthesisofCaOandCaTiO3intwoprocessesandthenthemixingofthetwoformthefinalproduct.TheCaOparticlesaremuchsmallerthanthoseproducedfromthepreviousmethodandbetterdispersedintheCaTiO3matrix.AnoutlineofthisprocedureisshownbelowinFigure2.14.TheleftpartoftheFigureisthecalciumoxidedispersionchain. Figure2.14FlowChartofaModifiedMethodforthePreparationofaPelletsUsingAlkoxideMethodwithaDispersionChain(Sakuraietal.,1995)

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31Againpelletsweremadebybothmethods(conventionalandmodified)andtheirperformanceswerecompared.TheconventionalmethodreferstothefirstalkoxidechemistrymethodoutlinedaboveinFigure2.11aboveandthemodifiedmethodreferstothealkoxidechemistrymethodwiththedispersionchainoutlineinFigure2.14above.Themostdramaticimprovementcanprobablybeseenintheratesforhydrolysis(Figure2.15).Thoughthereisimprovementinthebrominationitisinsignificantcomparedtotheincreaseinrateofhydrolysis.Theproductionisgovernedbytheslowestreaction(hydrolysisreaction).TheimprovementinthehydrolysisratethereforeimprovedtheH2productionratesignificantly. Figure2.15ComparisonoftheSolidConversionProfilesofBromination(Left)andHydrolysis(Right)BetweentheConventionalMethod(Alkoxide)andModifiedMethod(AlkoxidewithDispersionChain)(Sakuraietal.,1995)Sakuraietal.(1995)alsoexperimentallyfoundtheeffectoftheratioofcalciumoxidetocalciumtitanateontheconversion.Ofthefourratiostestedthe.76CaO/CaTiO3hadthehighestconversionatabout80%conversion.Figure2.16showstheirdata.

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32 Figure2.16ComparisonBetweenComputedandObservedTimeHistoriesofBromination(CaO/CaTiO3=.45,.76,1.01,2.01)(Sakuraietal.,1995)Sakuraietal.(1996)reportedresultsfromanin-depthstudyonporosityofpelletsmadefromthealkoxidemethod(Aiharaetal.,1990).Thesepelletsweresubjectedtoanumberofcyclesandtheporositywasmeasuredaftereachcycle(Figure2.17).Thedifferentialporosityfrom.01mto354misshown(Figure2.18)forsamplepelletsbeforeandafterbromination.Itcanbeseenthatmostoftheporevolumeinconcentratedinthe1to5micronrange.Thiswasthelatestsignificantdatapublishedonthecalciumpellets. Figure2.17ChangeofPoreVolumeinCyclicOperation(U;Unreacted,B1andB2;After1stand2ndBromination,H1,H2,andH3;After1st,2nd,and3rdHydrolysis,Respectively)(Sakuraietal.,1996)

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33 Figure2.18ChangeofPoreVolumeDuringBromination(Sakuraietal.,1996)ThroughouttheseStudies,theHydrolysisofCaO(Eq.2.1)isratelimiting.ItdeterminesH2productionrateintheUT-3process.Itisalsothehighesttemperaturereaction.ThecurrentstudythereforeattemptstoformulateCaOpelletswithmorefavorablecharacteristics.StrengthsandWeaknessesoftheUT-3ThermochemicalProcessTheUT-3thermochemicalcyclecanbeacommerciallyviableprocess.Simulationindicatesthatitisenergyefficientandcanbecomecostcompetitiveasthepricesoffossilfuelsrise.Theprocesshasrelativelylowtemperaturesforathermochemicalprocesswhichcanbeachievedthroughsolarconcentratorsorthroughheliumfromhightemperaturenuclearreactors.Iftheheatfortheprocessissuppliedinthismannernocarbondioxidewillbeproduced.Anotheradvantageoftheprocessisthatthesolidreactantsremainstationaryinthereactorseliminatingtheneedformovingbedreactorwhichwouldotherwiseaddagreatdealofoperationcomplexity.ThereareweaknessesoftheUT-3processaswell.Theprocessisinbatchmodeandislimitedbytheslowestreactionwhichisabout1hour.Therearestillproblemsthat

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34havetobesolvedinhydrogenseparationathightemperaturesfromcorrosivegas.Thisproblem,however,isinherentinmostthermochemicalcycles.Inadditionboththecalciumandironpelletsneedtobedurableandhaveacycliclifethatwouldmakethemeconomical.Thismaybeamajordrawbackoftheprocess.DespitetheseweaknessestheUT-3thermochemicalprocessisoneofthetwonon-hybridcyclesbeingstudied,theotherbeingtheGeneralAtomicprocessmentionedearlier.Teoetal.(2005)wereskepticalofthepossibilityoftheUT-3thermochemicalprocessasafeasiblemeanstoproducehydrogen.Theydidananalysiswhichpredictsamuchlowerefficiencyoflessthan7%.CalciumOxideSolidReactantWhendesigningasolidreactantfortheUT-3thermochemicalprocessanumberofcharacteristicshadtobeconsideredwithintheconfinesoftheprocess.TheUT-3thermochemicalprocessiscyclic.Asolidreactantthatcancontinuetoreactfromonecycletothenexthadtobedesigned.UT-3researchersselectedapelletconfigurationwherethesolidreactantsweredispersedonasolidporoussubstrate.Suchformulationpreventsthecarryoverofsolidreactantinthegaseousstream.Properformulationofaporoussubstrateandhighdispersionofthesolidreactantcanincreasetheconversionandimprovethereactionrates.Apelletformofsolidreactantwithminimaldegradationcanalsobeusedinastandardfixedbedreactor.Manyinterdependentphysicalandchemicalprocesseswillbeconsideredwhendesigningthepellets.Thedesigncharacteristicswhichneedtobeconsideredaresimilartothoseconsideredwhendesigningacatalyst.Thesecharacteristicsareinterdependentsothattheyneedtobeconsideredtogetherandcannotbeisolatedtoalargedegree.Thesecharacteristicsandtheirinterdependencieswillbediscussedbelow.

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35PhysicalCharacteristicsPhysicalcharacteristicsrefertothosepropertiesthathavetodowiththephysicalgeometryandmechanicsofthematerial.Porosityandstrengtharetwoimportantphysicalcharacteristicsthatmustbeconsideredwhendesigningthepellets.PorosityPorosityisthetermforthecharacterizationoftheporesofamaterial.Theporosityofamaterialisexplainedusingafewdifferentstatistics.Thefirstisthetotalsurfaceareawhichisimportantbecauseitisproportionaltothenumberofavailablechemicalreactionsites.Thesecondistheporesizewhichaffectsthediffusionratesthroughamaterial.AlltheseparameterscanbecorrelatedusingtheBJHequationtomanipulateisothermdatawhichwillbeexplainedintheanalyticresearchtoolssectioninChapter4.Thusaporesizedistributioncanbecreated.Thisallowstheresearchertounderstandwhatsizeporesareinthematerial.Poresizeshavebeensplitupintotwogroups.Microporositydescribesporessmallerthan0.5mwhereasmacroporosityreferstoporeslargerthan0.5m.Macroporescontributetodiffusioncharacteristicinsidethepelletwhilemicroporesincreasethesurfaceareaonwhichthesolidreactantcanbedispersed.Macroporesarealsonecessarytopreventpluggingofdiffusionpathduetovolumechangeofthereactantsduringthecyclicprocess.StrengthThestrengthobviouslyreferstothestrengthofthepelletstoresistdisintegration.StrengthofthepelletsmustalsobeconsideredwiththethermalshockthatcomeswiththecyclicoscillationsoftheUT-3process.Strengthalsoreferstotheabilityofthematerialtokeepitsporousstructureintactonamicrolevel.Themicrostrengthhelpstopreventreductioninporesurfaceareaandporevolume.Further,thepelletsmustsupport

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36theweightofothersimilarpellets.Iftheyarecrushedwithinthefixedbedtheywillcauseahigherpressuregradientinthereactorleadingtoalowerflowratesandgreatlyreducereactionsurfacearealeadingtolowerconversion.ChemicalCharacteristicsChemicalcompositionChemicalcompositionreferstothechemicalmakeupofthefinalpellets.Thisisimportantinthisparticularapplicationbecauseoneofthecomponents,calciumoxide,isachemicalreactant.Generally,reactionratesareproportionaltotheconcentrationofreactants,thusagreaterconcentrationusuallyyieldsahigherreactionrate.Thesolidreactant,calciumoxideshouldbemaximizedbutmustbebalancedwiththecharacteristicstrengthofthepellet,especiallyonthesmallerscale.Thecalciumtitanateformstheporoussubstrateonwhichthecalciumoxideisdispersed.Ifthesestructurescollapsethesurfaceareaisgreatlyreducedandthusthereactionratesaregreatlyreduced.ReactivityReactivityreferstotheabilityofthesolidreactant,CaOorCaBr2,toreactwiththegaseousreactant,Br2orH2Orespectively.Thisparameterdependsonthesurfaceofthesolidreactantthatisdispersedandthediffusionpathtothesolidreactantandoutofthepellet.Thereactivityishighlydependentontheporosityofthematerialasbothoverallsurfaceareaanddiffusionratesaredeterminedfromporosity.Reactivitycanalsodependontheconcentrationofthereactantandsotheamountofreactantshouldbeincreasedasmuchaspossiblewithoutsacrificingtheotherneededcharacteristicsespeciallythestrength.Therateofreactionandconversionarethemainmeasureofreactivity.Thereactionratesaregenerallydependantonconcentrationsofreactantsandproductsandtemperature.Conversionisaquantitytodescribetheextentofreaction.

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37Temperature,pressure,reactionrates,typeofreactor,andconcentrationsallhaveaneffectontheconversion.DegradationDegradationreferstothelossofreactivityfromcycletocycle.Thiscanhappeninanumberofways.Degradationisusuallyduetoporecloggingorporestructurebreakdown.Porecloggingoccurswhenlargerparticlesreactandbondtoasiteformerlyoccupiedbyasmallerparticle.ThemoleculesvolumeofCaBr2isgreaterthanCaOwhichcouldleadtoporecloggingafterthebrominationreaction.Porecloggingcanalsooccurdotogrowthofagglomerateswhichusuallyhappensathightemperaturesthroughsintering.Porestructurescanbreakdownduetoexternalforces(fixedbedweight)andalsosmallforcesfromthegasesenteringandexitingandmoleculesformingandreformingbreakthebondswhichmaintaintheintegrityofthepores.ResearchObjectiveTheobjectiveoftheresearchprojectattheUniversityofFloridaistoinvestigatethefeasibilityoftheUT-3thermochemicalprocessandexplorethepossibilityofloweringtheoperatingtemperature.Thehighesttemperaturereactionisreaction1(Eq.2.1)at760CinwhichCaBr2isconvertedtoCaO.SolidreactantswithacceptablecharacteristicsmustbedevelopedtoevaluatetheperformanceoftheUT-3process.Thisresearchisthereforefocusedondevelopingthesolidreactantforthecalciumreactions(Eq.2.1,2.2).TheobjectiveofthepresentresearchistodevelopamethodofproducingthecalciumsolidreactantfortheUT-3process.Thesolidreactantwillbemadeintopelletsforourresearch.Itisacommonpracticetomakecatalystintopelletmaterialsforuseinfixedbedreactors.Pelletsprovideagoodsurfacearea,lowdegradation,andeven

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38transportofgaseousreactantsandproductsthroughthereactor.ThoughthesolidreactantsarenotcatalystsintheUT-3process,pelletsareagoodchoicefortheformofthesolidreactant.Ifdesignedandfabricatedcorrectlytheycanprovidethesamebenefitsasinacatalystsystem.TherearemanystepsthatneedtobetakeninordertocreatepelletsfortheUT-3thermochemicalprocess.Asummaryofthestrategytomakethepelletsispresentedbelowforboththechemicalformulationandphysicalprocedures.Bothwillagainbeexplainedingreaterdetailintheproceduralsection.ChemistryFormulationAchemicalprocedurewillbeusedtomaketwodifferentsizesofagglomerates.ThefirstwillbelargerparticleofCaTiO3andsecondwillbethesmallerwillbeCaO.Inthefinalformationthelargeragglomerateswillhavespacebetweenthemwhichwillresultinmacroporosity.Theselargeragglomeratesthemselvesarenotsolidthough.Theyhavemicroporosityaswell.Inthiswaythepelletswillhavethebimodalporosity.ThesmalleragglomeratesofCaOwillbedispersedintothemicroporeswhichwillgiveagoodreactionareaforthepelletswhileatthesametimemaintainingthemacroporosityneededfordiffusion.Thischemicalprocedureiscomplex.TheCaTiO3agglomeratesmustbemadebigenoughtocreatethemacroporosityinthepellet.TheagglomeratesthemselvesshouldhavemicroporositiesforCaOdispersion.TheCaOparticlemustbeverysmallinordertobedispersedintothemicroporesoftheCaTiO3andnotclogthem.Parameterswhichwillbeexaminedaremixingratiosandheatingprocedures.Theeffectoftheseparameterswillbeevaluatedbyporosity,strength,andchemicalcompositionmeasurements.

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39PhysicalFormationAfterthechemicalprocedureisdevelopedandmixtureofCaTiO3andCaOobtained,themixturemustbeformedintopellets.Theprecursorsmustbedriedtoasolidpowderform.Thepowderthenwillbemoldedinacompressionmoldtocreatepellets.Thepelletswillthenbeheatedtoatemperaturetoachievecontrolledsinteringandadjusttheporositydistributionandstrengthofthepellets.Parameterswhichwillbeexaminedaremoldcompressionforce,dryingtemperature,sinteringtemperatureandduration.Porosityandstrengthwillbethedependentvariablesbywhichtheeffectoftheseparameterswillbeevaluated.

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40CHAPTER3SOLIDREACTANTPresentedinthischapteraretheprocedurestoproducetheprecursorsforpellets,includingtheoriginalchemicalformulation,themodifiedchemicalformulationusedbyUT-3cycleresearchers,andthephysicalmethodtomoldandtreatthepellets.Therehavebeenseveralproblemsduringthecourseoftheworkleadingtoanumberofchangestoboththechemicalandphysicalprocedures.Theseproblems,theircauses,andproceduralchangesarealsodiscussedinthischapter.Sol-GelChemistryThesol-gelprocessisanapproachforpreparingthermally,chemically,andmechanicallystablematerialswithcontrolledporositiesusedintheareaofgasseparation,catalysis,membranereactors,sensors,andabsorbents.Startingfromamolecularprecursor(sol),anoxidenetwork(gel)isobtainedviainorganicpolymerizationreactions.Thesereactionsoccurinsolutionandhencethetermsol-gelprocessingisused(BrinkerandScherer).Ascomparedtotheconventionalpowderroutetheseprocessesoffermanyadvantages:1.Homogeneousmulti-componentsystemscaneasilybeobtainedbymixingthemolecularprecursorsolutionswithbetterkineticsandyields.2.Thescaleofmixingisconsiderablysmallerwhichenablesgreaterdispersion3.Thetemperaturesrequiredinsol-gelprocessesaremarkedlylow.

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414.Carefulmanipulationofoperatingparameters(temperature,pH,watercontent)canyieldproductssuitablefordiverseapplications.5.Thedeformationpropertiesofthesolorgelsallowtheformationoffibers,filmsorcompositesbysuchtechniquesasspinning,dip-coatingorimpregnation.Analkoxideisanioniccompoundformedbytheremovalofhydrogenionsfromthehydroxyl(OH-)groupinanalcoholusingreactivemetals.(Frostburg)Thealkoxideusedinthecurrentchemicalprocessiscalciumethoxide(Ca(C2H5O)2).MetalalkoxidesM(OR)nareversatilemolecularprecursorsforthesol-gelsynthesisofmetaloxides.Thereareknownalkoxidesfrommanymetalsincludingthetransitionmetalelements.Thedifferenceintransitionmetalsol-gelchemistrycomparedtotherestofthemetalelementsarisesfromtwofactors:Thehigherelectropositivityoftransitionmetalsleadstoamuchhigherelectrophiliccharactersofthemetal.Thepossibilityexistsformosttransitionmetalstoexhibitseveralcoordinationssothatfullcoordinationisusuallynotsatisfiedintheprecursors(alkoxides).Thisincreasestheprobabilityofaddingligandstothetransitionmetalionwhichleadstodiversephysicalandchemicalproperties.Asaresult,transitionmetalalkoxidesaremuchmorereactive.Theymustbehandledwithcare,intheabsenceofmoisture.Theyreadilyformprecipitates(particles)ratherthangels(networks)whenwaterisadded.Thesol-gelprocessprimarilyproceedsintwosteps:hydrolysis,thencondensation.HydrolysisTheelectronegativealkoxogroups(OR)makethemetalatomrelativelyelectropositiveandthereforehighlypronetonucleophillicattack.Metalalkoxidesarethereforeextremelyreactivewithwaterleadingtotheformationofhydroxidesorhydrousoxides.Theoverallreactioncanbewrittenas:

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42M(OR)n+nH2OM(OH)n+nROHThestepwiseprogressofhydrolysisisshownhere(Sanchezetal.,1988). (a)1.Thefirststep(a)isanucleophillicadditionofawatermoleculetothepositivelychargedmetalatomM.Thisleadstoatransitionstate(b)wherethecoordinationnumberofMhasincreasedbyone. (b)2.Thesecondstepinvolvesaprotontransferwith(b)leadingtotheintermediate(c).AprotonfromtheenteringwatermoleculeistransferredtothenegativelychargedoxygenoftheadjacentORgroup. (c)3.Thethirdstepisthedepartureofthemoreelectropositivegroupwithinthetransitionstate(c).CondensationCondensationisacomplexprocessandcanoccurassoonashydroxogroupsaregeneratedfromhydrolysis.Dependingonexperiment,threecompetitivemechanismshavetobeconsidered,namely:alcoxolation,oxolation,andolation(Livageetal.,1988)1.Alcoxolationisareactionbywhichabridgingoxogroupisformedthroughtheeliminationofanalcoholmolecule.

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432.Oxolationfollowsthesamemechanismasalcoxolation,buttheRgroupoftheleavingspeciesisaprotonandtheleavinggroupiswater. 3.Olationcanoccurwhenthefullcoordinationofthemetalatomisnotinthealkoxide.Inthiscasebridginghydrogroupscanbeformedthroughtheeliminationofasolventmolecule(ROHorwater) Thecondensationreactioncancontinuetobuildlargerandlargermoleculesthroughpolymerization.Apolymercontainshundredsofthousandsofunitscalledmonomerswhicharecapableofformingatleasttwobondswithneighboringmolecules.Thepolymerizationmayresultintocompactparticlestructureorextendedstructure(network).Particlescanbeeasilymoldedtoformpellets.Highwater/alkoxidemolarratios,highpH,andhightemperaturespromoteparticleformation(Brinkeretal.,1994).Lowwater/alkoxidemolarratios,moderateacidity,andlowtemperaturespromoteextendedstructures.Thisexperimenthasthefollowingexpectedreactions:1.FormationofCalciumEthoxideCa+2C2H5OHCa(C2H5O)2+H2(3.1)2.HydrolysisofCa(OC2H5)2andTi(OC3H7)4H2O+Ca(OC2H5)2Ca(OC2H5)(OH)+C2H5OH(3.2)H2O+Ti(OC3H7)4Ti(OC3H7)3(OH)+C3H7OH(3.3)3.Condensationbyoxalation

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44Ca(OC2H5)(OH)+Ti(OC3H7)3(OH)(OC2H5)Ca-O-Ti(OC3H7)3+H2O(3.4)4.Furthercondesation(OC2H5)Ca-O-Ti(OC3H7)3+HeatingCaTiO3Network(3.5)Itshouldbenotedthatthisisverycomplexchemistrywhichcannotbecompletelypredicted.Equation3.2showsonehydroxylgroupreplacingonealkoxogrouponeachthetitaniumandcalciummetalatoms.Inactualitythisreactionmayoccurmorethanonce.Thenumberofhydroxylandalkoxogroupsshownasreactantsforcondensationwillalsolikewisevary(Eq.3.4).Equation3.5simplystatesthatmorecondensationoccursthroughchemistry,drying,andheatingwhichultimatelyformstheCaTiO3network.ChemicalFormulationThechemicalformulationoftheprecursorsforthepelletsisaverysensitiveandimportantstepintheprocess.Sol-gelprocessingdescribedaboveisused.Withinthismethodthereareanumberofparametersthatcanbechangedwhichcangreatlyaffectthepropertiesoftheresultantproduct.Theseparametersincludemolarratiosbetweencalcium,ethanol,water,andtitaniumisopropoxide,pH,temperature,andproceduralsteps.TheproceduresdevelopedbyAiharaetal.publishedin1990andlaterinmoredetail2001wereusedasguidelinesinthecurrentworkofsynthesisoftheprecursors.QualitativeinvestigationAqualitativestudywasconductedtoobservethereactions.Thereactantsweremixedwitheachothertoseewhatcouldbeexpected.Table3.1showsthequalitativeobservationsofthisinvestigation.Alltheseexperimentswereconductedatroomtemperatureinair.

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45Table3.1QualitativeReactionStudy Ca Eth. Ti.Iso. D.W. Calcium XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX GWPNARVED Ethanol GWP XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX WFPDFS TitaniumIsopropoxide NARWFP XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX SFWP DionizedWater VED DFS SFWP XXXXX GWP-Globularwhiteprecipitateforms(afterstirring)NAR-NoapparentreactionVED-CaviolentlyexothermicallydissolvesindionizedwaterproducingbubblesWFP-WhitefibrousprecipitateformsSFWP-SpontaneousreactionwithwhiteprecipitateandgasevolutionDFS-DissolvesformingasolutionOriginalprocedureTheproceduredetailsgivenintheoriginalpublication(Aiharaetal.,1990)arefarfromcomplete.Figure3.1showsanoutlineofthisprocedure.Thisoutlinewasfollowedexceptgraphitepowderwasnotadded.Graphiteisusedasanadditivetoincreaseporosityduringcalcination.Thisparameterwaseliminatedatthistimetoincreaseunderstandingoftheotherparametersaffectingtheporosity. Figure3.1ProductionProcessofthePelletUsingCaandTiAlkoxide(Aiharaetal.,1990)

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46Though,thisprocedurelooksfairlyeasytofollowthereweremanydifficultiesinperformingthenecessarysteps.Thisfirststep,combiningmetalcalciumandethanoltoformcalciumethoxideprovedtobeamajordifficulty.Calciumdoesnotreactreadilywithethanol.Inordertotrytoremedythissituationtwosolutionswereproposed.1.Heattheethanolandcalciummixturetoseeifthereactionwouldproceedquickeratahighertemperature.Thiswasdonebutnoreactionwasobserveduptoboilingtemperaturesofethanol.Becauseofthelossofethanoltoevaporationandboilingthemixturewoulddryoutifitwasleftforlongperiodsoftime.Noappreciablereactionwasseeninthistimeframe.Later,itwasfoundthatthereactuallyisanoticeablereactionthatoccursbetween73Candtheboilingpointofethanol79C.Thereactionformsbubblesofhydrogen.Thismayhavebeenoverlookedasaslowboilbecausethetemperatureissoclosetoboilingofethanol.2.Stirthesolutioncoveredtoseeifthereactionwouldproceedfasterwhilestirred.Again,therewasnoappreciablereactionobserved.Thismixturewasleftandtheevaporationratewasslowerinthissetup.Thus,thereactioncouldbeobservedoveralongerperiodoftime.Awhiteprecipitatecouldbeseenafterabouttwodays.Thewhiteprecipitatethoughttobethecalciumethoxidewasfinallyformed.Theprecipitateseemedtobewhiteandglobularandsettledtothebottomofthebeakerafterseveralhours.Thismethodwasadoptedasthefirststepoftheoriginalchemicalformulation.Theamountofcalciumthatwouldreactinethanolwasverysmall.Laterthrougha10daytestthereactionlimitwasfoundtobeabout0.0015g/mL.Thiswasdonebytaking0.38gramscalciumandaddingethanoloveranumberofdaysuntilthecalciumwasreacted.After10daysthevolumeofethanoladdedtoreactallthecalciumwas250

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47mL.Totrytoincreasetheconcentrationofcalciumsomeethanolcouldbeevaporatedwithoutsignsofblackcalciumreforming.However,othercalciumcompoundsmayhavebeenformed.Next,18mLoftitaniumisopropoxidewasaddedto40mLofthismixture.Astringingprecipitatewasspontaneouslyformed.Thebeakerbecamenoticeablywarmerindicatingthatthiswasanexothermicreaction.Thisprecipitateappearedtobethesamethatwasfoundinthequalitativestudyofreactionbetweenethanolandtitaniumisopropoxide(Table3.1).Themixturewasstirredfor5minutesandthestringyprecipitatebrokeapartveryeasily.Nextthemixturewashydrolyzedusing12mLofdionizedwater.Thebeakeragainbecamewarmerindicatinganexothermicreaction.Thewaterseemedtoreactwiththeprecipitateformingapowder-likeprecipitate.Themixturewasagainstirredfor5minutes.Dryingproceduresdescribedlaterinthischapterwerethenfollowedtoeliminateethanolandwaterfromtheliquorleavingapowder.Thepowderwasmoldedintopellets.Thefeedbackfromthispelletizationstudywasusedtoimprovethepelletmoldandpelletizationtechniqueandtodetermineaffectsofsinteringtemperature.ThisprocedurewasexpectedtoyieldCaOdispersedinCaTiO3matrix.However,sincetheratioofcalciumtotitaniumwassmall,itissuspected(andlaterconfirmedviaRamanspectroscopy)thatnotmuchcalciumtitanateorcalciumoxidewasformed.Mostofthesolidwasanataseorrutiletitaniumoxide.Anotherindicationthatcalciumtitanatedidnotformisthatcalciumtitanateexistsindifferentcolorsrangingfromorangetoblackbutitcannotbebrightwhiteastheresultantpowderwas.Thisindicatedthatthepowder

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48wasTiO2whichwaslaterconfirmedbyRamanspectroscopytobeTiO2(anataseandrutile).Thus,anewchemicalprocedurehadtobedesigned.Thisdesignneededtoincreasethecalciumintheprecursors.ModifiedprocedureApaperbyoneoftheoriginalUT-3authors(Aiharaetal.,2001)givesmoredetailintothemethodsusedforthechemicalformulationofthecalciumtitanate(CaTiO3)precursor.Thisprocedureimpliedthatthereactionswithinthealkoxideprocedureareverysensitivetowaterandpossiblysensitivetooxygen.Anewsetupwasconstructedtoperformtheanhydronousformulation.ThesetupisshownbelowinFigure3.2. Figure3.2ThreeMouthedFlaskonStirringHeater

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49Athreemouthedflaskisusedasthevesseltocarryoutthenewprocedure.Thefirstopeninghasarubberstoppercoveredwithparafilmwithatubeandamercurythermometer.Thetubeisconnectedtoanitrogensupplyandusedtopurgetheflaskwithnitrogen.Thethermometerisusedtomonitorthetemperatureofthefluidinsidethebeaker.Thesecondopeninghasacondensertocondenseanyvaporthatcouldevaporateorboilfromthesystemduetoheating.Thethirdopeninghasanadaptorwithasiliconseptum.Chemicalsareaddedthroughtheseptumbyasyringetoinsureananhydronousandoxygenfreeenvironmentduringtheentireprocess.Theflaskisplacedonahotplatewhichprovidestheheatfortherefluxprocesses.Alloftheequipmentisproperlysupportedusingmetalstandsandclamps.Aiharaetal.(2001)usedanitrogenenvironmentandfollowedthestepsshownbelowinFigure3.3.TheratiosofthereagentsarepresentedinTable3.2.ThemolarratiosareshownwithrespecttoCametal.The*indicatesthatinstep7dionizedwaterandethanolareaddedinasolution.Table3.2OriginalMixingRatiosforModifiedChemicalFormulationProcedure ProceduralStep Substance Amount Units MolarRatio Step1CalciumMetal1.00[g]1Steps2,4,&7AnhydronousEthanol14.6[mL]10Step5TitaniumIsopropoxide7.4[mL]1Step7*DionizedWater1.8[mL]4 Step7* Ethanol 7.2 [mL] 4.9 TherefluxingstepinAiharas,etal.procedure(step3)wasinvestigatedtoseehowlongthereactiontooktofullyreact.Anappreciablereactionoccurredfromabout73Ctoabout78C.Bubblesareobservedformingonthecalcium.ThisisthehydrogenproductfromthereactionshowninEq.3.1.Inthe30minutetimethatAiharaetal.prescribemuchoftheblackcalciumpowderremainedthoughanappreciableamountofwhitepowderalsocouldbeseen.Thereactionwaswatchedfor5hourswithoutmuch

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50change.Itwasconcludedthatthereactionhadreachedequilibriumasnonoticeablechangewasobservedbetween30minutesand5hours.Therefore,thetimeof30minutesforstep3wasadopted.Figure3.3FlowDiagramofProcedureOutlinedbyAiharaetal.(2001) Step1:CaMetalinaNitrogenenvironment Step3:Stirfor5hours@75C(formsCalciumEthoxide,Ca(OC 2 H 5 ) 2 Step4:AddTitaniumIsopropoxide Step5:Stirfor30minutes@75C Step2:AddAnhydronousEthanolC2H5OH Step7:Stirfor1hr@75C Step6:Add20%VolumeSolutionofWater inEthanol Step8:PourIntopetridishanddry overnight Step9:Heat@430C Step10:Makeintopelletsusing0.25metrictoncompression Step11:SinterinFurnaceupto900C

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51Stringentstepsbelowweretakentoensureoxygenfreeandanhydronouscondition.1.Cleananddryflask,condenser,andotherequipment.2.Thecalciumsampleismeasuredontheelectronicscaleandthendroppedintotheflaskthroughtheopeningwiththenitrogenandthermometer.3.TheTeflonstirbarisdroppedintotheflaskthroughtheopeningwiththenitrogenandthermometer4.Thecondenserandseptumadaptorarecoatedwithathinlayerofpetroleumjellytopreventseizingbeforeconnectingtotheflask.5.Thenitrogenvalvesareopenedtoallowaverysmallflowtotheflask.6.Watertothecondenseristurnedon.7.Wait5minutesfornitrogentopurgesystem.8.Anhydronousethanolisextractedbysyringefromitscontaineranddischargedintothesystemthroughthesiliconsepta.9.Theheaterstirreristurnedontoraisethetemperatureofthemixturetobetween72Cand76C.Anoticeablereactionoccursinthistemperaturerangeformingawhite/grayprecipitate.Thestirrerissettomaintaingoodstirring.10.Heatingproceedsfor30minutes.11.Themixtureisdilutedusingthesameamountofethanolasinstep9.12.Titaniumisopropoxideisextractedfromitscontainerviasyringe.Thecorrectproportionisinjectedintotheflaskagainthroughthesiliconsepta.Themixtureisheatedbetween72Cand76Cfor30minutes.13.Asolutionof20%byvolumeofwaterinethanolismadeinabeaker.14.Asyringeisusedtoinsertthewaterethanolsolutionintotheflaskinordertomaintainanoxygenfreeenvironment.Areactionoccursspontaneouslyturningmostoftheprecipitateabrightwhite.15.Themixtureisstirredandheatedforanotherhour.Inthishouralloftheprecipitatebecomeswhiteexceptforasmallamountwhenthecalciumtotitaniumratiosare3and4.

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52Aproblemencounteredwiththisprocedurewastheformationofapurpleratherthanwhite/grayprecipitateforminginstep9.Theproblemwasthoughttobeinthecleaningoftheflaskfromruntorun.Anewcleaningprocedureforstep1wasconsideredsothatthechemistrywouldnotbeaffectedbyresidueinthecontainerfrompreviousrunsorresiduefromtheactualcleaningagent.Arigorouscleaningwasdoneincludingbothanacidbathandbasebath.However,thepurpleprecipitateagainformed.Itwassuggestedthattherubberstopperspluggingtheflaskmaybetheproblem.Theywerecoveredwithparafilmandthepurpleprecipitateceasedtoform.Intheinterestoftimealessthoroughcleaningprocedurecanbeusedwhichdoesnotaffectthechemistry.MixingratiosTheinitialmixingratiosforthenewprocedurecamefromAiharaetal.(2001).However,thatprocedurewasdesignedtomakecalciumtitanateandthereforeusesa1to1ratiobetweencalciumandtitanium.Inordertoalsomakecalciumoxidemorecalciumhadtobeused.Ratiosofcalciumtotitaniumof2,3,and4wereused.Otherparameterswerechangedbecauseoftheequipmentsetupandtoaccommodatefortheextracalcium.ThesequantitiescanbeseeninAppendixC.TheoriginalratiosusedbyAiharaetal.arepresentedingrams,milliliters,andmolesinTable3.2above.PhysicalProceduresThesynthesizedprecursorsweremoldedintopellets.Aprocedurewasdevelopedwhichconsistsoffirstdrying,thenmolding,andfinallysintering.Thesethreestepswillbedescribedindetailinthefollowingsections.DryingTheliquorfromtheprecursorsynthesishasasignificantamountofethanolandwaterleftinit.Theliquorisstirredtoevenlydistributetheparticlesinthecontainer.

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53Theliquorispouredintopetridishes.Thesepetridishesaresetunderanexhaustingfumehood.Mostoftheliquidevaporatesoffafter18-20hours,thoughtheresultantpowderisstillslightlymoist.Thepowderisputintoaquartzcrucibleandheatedinafurnaceto430Cfor1hour.Itwasfoundthatpelletsmoldedusingthepowderdisintegratedwhenheatedbetween300Cand400C.Itwassuspectedthattherewerevolatilesinthepelletswhichcontributetothepelletfailure.Therefore,apreheatingstepwasadded.Thepelletsmaintainedtheirintegrityathighertemperaturesduringthesinteringstepdescribedlater.Thisstepwasnecessarybeforemoldingthepellets.Italsoeliminatesanywaterorethanolwhichwasnotevaporatedintheovernightdrying.MoldingHydraulicpressAhandpumpeduni-axialhydraulicpress(Figure3.4)isusedtosupplythecompressionforcetothemoldassembly.ItisaCarverhydraulicmodel#3912witha5-1/8maximumramstroke.Thepressislocatedinroom1AoftheNuclearFieldBuilding.Therearetwoparallelplatesonthepress.Theupperisplateonascrewandfixedinplaceusingnuts.Thebottomplateisconnectedtoahydrauliccylinderwhichisraisedtosupplytheforceastheleverarmispusheddown.Aforcegaugeonthepressinunitsonmetrictonsisratedupto11metrictons.A304-SSmoldassembly(Figure3.5)wasfabricatedandusedinthehydraulicpressdescribedabovetomakepelletsof3/16Dx4/16-6/16H.Compressionforceonthepresswasvariedfrom0.3MT(metrictons)to2MT.Problemswithplasticyieldingandseizingoftheplungerwiththemoldwereexperiencedataxialloadsgreaterthan1.0MTandsothepelletswerecastwithforceslessthan1MT.AstepbystepprocedureofthisprocesscanbeseeninAppendixC.

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54 Figure3.4HandPumpedUni-AxialHydraulicPressforPelletProductionOriginalmold ForceFromPress Figure3.5PelletMoldAssembly

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55Themoldassemblyconsistedof5partsasshowninFigure3.6whicharetheplate,plungers,cap,mold,andextractionpiece.Theplatewasthebottompieceonwhichthemoldwassupportedandwasthesurfacethepelletwascompressedagainst.Italsohelpedtomovethefullassemblyinandoutofthepress. MoldPlateCapExtractionPiecePlungersFigure3.6PelletMoldingAssemblyPartsTheplungerswereusedintwodifferentmannersandsotwodifferentlengthplungerswerefabricated.Theshorterplungerswereusedtocompressthepellets.Generally,theshorterplungershadagreatercompressionforceonthem.Theshorterlengthshelpedtopreventbendingfromanyeccentricforces.Thelongerplungerscouldbeusedtopushthepelletsoutofthemoldandcouldbepulledouteasilybecausetheirextralengthallowedroomforgripping.Thecapwasthetoppiecewhichheldtheplungersverticalwhichalsohelpedtoreducenon-axialforceswhichwouldleadtobucklingandbending.Ithasaholedrilledabout0.5indepthwitha0.1875drillbitanda0.1895reamer.Themoldhasboreswherethepowderispositionedand

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56compacted.Theseboresaremadeslightlylargerthanthoseinthecap.Theboreswereobservedtoexpandaftermultipleusesatcompressionforcescloseto1metricton.Theboresweremadeusing0.2031drillbitandreamer.Theextractionpieceisonlyusedtoextractthepellet.Itisessentiallyaspacerbetweenthemoldandthetopsurfaceofthepress.Ithasisahollowcylindricalpiecewhichtransferstheforcetotheoutermoldingwhilegivingnoresistanceinthecenterwherethepelletisextracted.Theextractionpieceallowsthepellettobepushedoutintothehollowspaceitcontains.Asdiscussedinchapter2,alowcompactionforceisexpectedtoyieldhigherporosityinthepellet.However,lowercompactionforcemayalsoreducethestrengthofthepellet.Thesetwofactorswereconsideredtoarriveattheoptimummoldingprocedure.Fortheoriginalchemicalformulationprocedureaforcecloseto1metrictongavethebeststrength.Wholepelletswereformedwithforcesaslowas0.5metrictonsbutanoticeabledepreciationinstrengthwasobservedduringhandlingthepellets.Itwasfoundthatpelletsmadefromprecursorswith0.25-2percentageofgraphitecouldbemadewithacompactionforceofonly0.3metrictons.Alsostearicacidandammoniumcarbonatewerebothtriedasbindersat3%byweight.Bothactuallydegradedthestrengthofthepelletwhencomparedwithpelletsmadewiththesamecompressionwithoutthebinders.Forthemodifiedchemicalformulationprocedureaforceofonly0.25metrictonswasneededtogiveapproximatelythesamestrengthasthepelletscompressedat1metrictonusingthepreviouschemistry.Nographiteorbinderswereusedwiththemodifiedchemicalformulation.

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57ModificationsinmoldandmoldingprocedureManyproblemswereencounteredduringthefabricationofthemoldandthedevelopmentofthemoldingprocedure.Themostprevalentoperationalproblemwastheseizingoftheplungersinthemold.Thiswasattributedtotwodesignaspects.Thefirstwasthelengthofthemold.Theoriginalmoldwas1-1/16Thisoriginalmoldborealsohadaverylowradialclearancebetweenitandtheplungersothattherewouldbeminimumflowofthepowderintothespacebetweentheboreinthemoldandtheplunger.Thefrictionfromthepowderwedgingbetweenthemoldandtheplungersledtoseizing.Toeliminatethisproblemaprocedurewhichlimitedtheinsertionlengthoftheplungerwasusedtopreventseizureduringthecompressionprocess.Thecompressedpelletshowevercouldnotberemovedduetothefrictionforcesbetweenthewallsofthemoldandtheconsolidatedpowder.Aslightlylargerholewasdrilledtoseeifpelletscouldbemade.Thesameproblemsoccurred,thoughtheplungerrarelyseizedduringthecompressionphase.Whenthepelletswereextractedtheyfellapart.Itwasthoughtthatanunevendistributionofpressureinthepowderalongtheheightofthemoldduetofrictionledtothefailureofthesepellets.Anewmoldwasmadethatwas11/16inheight.Theholesonthismoldweredrilledslightlylargerthan0.1875at0.2031.Aprocedurewasusedwiththenewmoldsothatthepowderwouldbecompressedstepwiseusingmultiplecompactions.Theplungerwasremovedaftereveryincrementalcompactionandmorepowderwasaddedtofilltheholetothetop.Thepowderwasagaincompressed.Thiswasrepeateduntilthedesiredheightofthepelletwasreached.Thisprocessresultedinsomelongpellets.However,mostpelletswouldshearduringextractionintosmallfragilediskshapesor

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58separateintoshorterpellets.Theseizingbetweenthemoldandtheextractionplungeralsooccurredsometimes.Theprocedurewasfurthermodifiedasfollows.Onlyonefillwasused.Thepowderwascompressedbyhandasmuchapossibleandfilledtothetop.Thepresswasthenusedtocompressthemoldassemblywiththedesiredforce.Seizinghasnotoccurredusingthisprocedureduringcompressionorextraction.Thisprocedureisnowusedandgenerallyproduceswholepelletswiththeaveragedimensions~3/16Dx5/16Hthoughthisheightvariesslightlyfromruntorun.Ifcorrectlyexecutedthisprocedureyieldsausablepelleteverytime.Seizingprobablydoesnotoccurbecauseoftherelativelyshortcompressionlengthintothepowderathighpressures.Mostofthecompressionisatlowpressures.Thusthepowderinthegapbetweentheplungerandtheboreislooselypackedexceptforthebottom.Whentheplungerisbeingextractedithassomeplayintheaxialdirectionwhichcanloosenthetightlypackedpowdernearitslowerface.Thesurfaceareaoftheplungerexposedtotightlypackedpowderwasalsosmall.Similarly,duringextractionthesurfaceareaofthetightlypackedpowdercausingthefrictionwasreducedduetotheshortenedlengthofthepellets.Thusnoseizingoccurred.Thepelletsholdtogetherbetteralsobecausetheyarecompressedalltogether.Thepreviousmethodcompressesdifferentsections.Thesesectionsdontseemtoholdtogetherwell.Thusthecurrentmethodeliminatesseizingandprovidesareliablewaytoproducepellets.SinteringThepelletsaresinteredinafurnacetoincreasestrengthinthestructureofthepellet.Anincreaseintemperaturepromotesgrowthofthetitaniumnetwork.Theparticlesformintermolecularbondswhichhelptocreateaweb-likestructureincreasing

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59thestructuralstrengthofthepellets.However,intheprocesstheparticlesbecomelarger,whichoftenleadstoporeclogging.Therefore,thereisanoptimumsinteringprocedurewhichwillgivetheneededstrengthbutwithoutforfeitingthedesiredporosity.Atubularfurnacewithacontrollerisusedforsintering.AnATS(AppliedTestSystems)3310seriesfurnaceisusedandisalsolocatedinroom1AoftheNuclearFieldBuilding.ItcanbeseeninFigure3.7below.Thefurnacerangeisupto1300C.TheoperationofthefurnacecanbeprogrammedusingaPIDcontroller(KanthalSuper33,PC-120/240-20controller).Thecontrollerhasanoffseterrorandtemperaturesetpointsmustbeabove95C.Arecalibrationwasdoneinordertotrytoeliminatethisoffseterrorbutitstillpersisted.Duringthecalibrationtheerrorrangeinthetemperaturewasfoundtobeplusorminus10C.Aquartzcrucibleattachedtoaquartzhangerisusedtolowerthepelletsandpowderintothefurnace.Itisapproximately18inlengthandthecruciblehasadiameterof1.5andaheightof2.Thereareanumberofdifferentheatingschemesusedtovarythetemperatureandthedurationofheating.TheheatingschemesarepresentedinFigure3.8.Theheatingschemeshavebeenmodifiedbasedonthebehaviorofthepelletswithrespecttostrengthandmicroporosity.Theoriginalprocedurewasa100Cstepeveryhourupto700C.Thiswasusedtofirstfindthevolatilesaddressedearlierinthischapterbetween300Cand400Candtodetermineiftherewereanyotherdisintegrationtemperatures.Thenextschemethatwasusedwentto1000Coveranumberofhours.Theramptimesweretoallowanyreactionstooccurslowlysotheywouldnottobreakthepellets.Theslowrampincreasewasalsotopreventthermalshockfrombreakingthepellet.After1000Cheatingtheporosityofthepelletwasonlyabout3%ofthatofthe700Cpellet.However,

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60the1000Cheatedpelletwasstrongerthanthe700Cpellet.Amediumtemperatureabovethereactiontemperatureof760Cwassoughtthatwouldincreasestrengthyetgiveabetterporosity.Both800Cand900CheatingschemeswerethenusedtoinvestigatethisparametershowninFigure3.8asthemediumschemes.Theresultsinchapter5showacceptablecharacteristicswithinthesetemperatures. Figure3.7FurnaceUsedforSinteringProcess 02004006008001000120002468101214161820Time[hrs]Temperature[C] StepHeatingtoDiscoverVolatiles ReductioninPorosity1000C MediumSchemeto800C MediumSchemeto900C Figure3.8HeatingSchemesforPellets

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61CHAPTER4ANALYTICALTOOLSThetheoryandproceduresfortheanalyticaltoolsusedarepresentedinthischapter.Thetheorypresentedinthischapterismeanttogiveanunderstandingofsomeofthemethodsusedtocharacterizethepellets.Theprocedureisanoutlineofthestepstakenforeachinstrumenttogiveabasicunderstandingofitsoperation.MoredetailedprocedurescanbeseeninAppendixD.Presentedinthischapterarethreeanalyticaltools.Therearetwoporositytests.Thefirst,NitrogenAdsorption,measuresmicroporesusingtheorytopredictdistributionofporesizesbetween2nmand0.1m.Thesecond,calledMercuryPorosimetry,measuresmacroporesusingmercuryunderpressureandtheorytopredictdistributionofporesizesbetween2nmand~100m.Thoughmercuryporosimetrycanintrudeintosmallporesizes,BETmeasurementsaregenerallytakenasabettermeasurementofmicroporessmallerthan50nm.ThethirdtoolisRamanspectroscopywhichisusedtodeterminethechemicalcompositionofthepellets.Inadditiontothesetoolsachemicalprocedurewasdevelopedtohelpquantifythechemicalcompositionofthepellets.NitrogenAdsorptionTheoryThenitrogeninsidethesampletubeisabletocondenseontheporesurface.Thishasbeenmodeledbyanumberofscientistsovertheyears.Therearemonolayermodelsandmulti-layermodels.Someaccountforcapillaryeffectsinporesandothersdonot.

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62OneofthemostwidelyusedmodelsistheBETmultilayeradsorptionmodelwhichbuildsupontheLangmuirmonolayermodel.TheLangmuirmodelrelatestheconcentrationofvacantsitesandfilledsitesinadsorptionprocess.Themodelhasaformsimilartoakineticratelaw.Fornitrogenitis:rADkAPN2CvCN2SKA (4.1)whererADistherateofadsorption.kAisratecoefficientforadsorption.PN2isthepressureofnitrogen.Cvistheconcentrationofvacantsites.CN2-SistheconcentrationofsiteswhicharefilledbyaN2molecule.KAistheequilibriumadsorptionconstant.Though,thepressurefornitrogencanbemonitoredalltheotherparametersmustbeknownfromearlierexperimentation.However,whennitrogenisadsorbingonasurfacetherateisdifferentthanifitisformingamultilayeronpreviouslycondensednitrogen.ThusoncethetotalsurfaceiscoveredtherateisfairlyconstantandcanbeseenasthelinearmiddlesectionintheplottedBETisotherminFigure4.1.Thebeginningofthislinearregioncanbeusedtoestimatethetotalsurfaceareabasedonthevolumeadsorbed.BETIsothermABET(Brunauer,Emmett,andTeller,1938)Isothermdescribesthemultilayeradsorptioncaseformostsurfaces.However,inmaterialswithsmallporesthisequationbecomeslessaccurateduetocapillaryforcesacrossthepores.ThusanothercalculationschemehasbeendevelopedbyBarrett,Joyner,andHalenda(BJH).

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63 Figure4.1TypicalBETIsothermBJHPoreSizeDistributionBarrett,Joyner,andHalenda(BJH)derivedarelationshipthatcanbeusedtocreateporevolumedistributionsorporeareadistributionsoverarangeofporesizes(Barrettetal.,1951).IntheirderivationtheyusedtheproposedmechanismbyBETformultilayeradsorptionbutaccountforcapillarycondensation.Therearetwomainassumptionsthatareusedinthisderivation.Thefirstisthatalltheporesarecylindrical.Thesecondisthatnitrogenisadsorbedbytwomeansbeingcondensationontheporewallsandcapillarycondensation.ThederivationalsousestheKelvinequationrelatingpressure,surfacetension,andporeradius.Thismethodgivesresultswithin1to5%oftheBETtotalsurfaceareameasurement.

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64 rp1 rk1 t1 dt1 dt2 dt3 t4 rp2 t2 rk2 dt2 dt3 t4 rp3 t3 rk3 dt3 t4 (P/Po)1(P/Po)2(P/Po)3Vp1=R1*dV1Vp2=R2*dV2-R2*dT2*Ac1Vpn=Rn*dVn-Rn*dtnSUM[j=1ton](Acj)Figure4.2SchematicRepresentationofAssumedDesorptionMechanismShowingThreeDifferentPoresandDemonstratingtheThinningofthePhysicallyAdsorbedLayerOvertheFirstThreeDecrements(Barrettetal.,1951)Thepressureisincreasedgraduallyuntilthesampleissaturatedorhasreachedthepresetpressure.Thepressureisthenreducedstepwisesothatacertainvolumeofcondensateisemptiedfromacertainporesizerange;Thecondensatelayerthicknessisreducedorthecapillarycondensateisemptied.Avolumeofgasatagivenpressureismeasured.Thisvolumecanbeconvertedtocondensatevolumeknowingtheliquidandvapordensitiesofnitrogen.Thustheporevolumecanbefound.Thisisasimplifiedexplanationofthetheory.DetailedtreatmentofthetheoryisavailablebyBarrett,Joyner,andHalenda(1951).NitrogenadsorptionandmercuryporosimetryarealsoexplainedclearlyandcomparedbyWestermarck.(2000)ProcedureAQuantachromeNOVA1200machinelocatedattheParticleScienceEngineeringbuildingwasusedfornitrogenadsorptiontests.Twotothreepelletsareplacedinasamplecell(similartoatesttube).ThecellisplacedintoanairtightstationintheNOVAmachine.Itisthenvacuumoutgassedforadurationwhichdependsonthe

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65sample.Thesampleisheatedto200Cduringtheoutgassingprocedure.Outgassingelutesthemoisturefromthesample,makingtheporesurfaceavailablefornitrogenadsorption.Atthispointthemassandthedensityofthesampleareenteredintheinstrumentssoftware.Thesamplecellismovedtotheanalysisstation.Adewar(container)ofliquidnitrogenisraisedsothatthecellissurroundedbyliquidnitrogen.Startingfromverylowpressures,nitrogenisincrementallyaddedintothecell.Someofthisnitrogenisadsorbedintotheporesofthesample.Thepressureisincreaseduntilatmosphericpressure(770mmHg)isreached.Thepressureisthenreducedstepwise.Acertainamountofnitrogendesorbsateachpressure.Thisismeasuredthroughpressurereadingand/orairflowoutofthecell.Theamountofdesorbednitrogencanbecorrelatedtoporesizeusingtheory.MercuryPorosimetryTheoryThetheorybehindthemercuryporosimeterisrelativelysimplecomparedtothatofNitrogenAdsorption.MercuryporosimetryusesthecapillaryrelationshipgivenbyWashburnequation(Eq.4.2)tocalculateporesizebasedonpressure.D=-(4.2)dyne/cm),theporediametercanbecorrelatedtothepressureinsidethechamber.Mercuryporosimetrylikenitrogenadsorption,assumesthattheporesarecylindrical.Italsoassumesconstantmercuryproperties.

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66ProcedureTheQuantachromeAutoscan60MercuryPorosimeterintheParticleScienceEngineeringBuildingwasusedtomeasuretheporosityofthepellets.Aporoussampleisplacedinasmallglasscontainerwithalongthintubeatoneend.Theairisevacuatedfromthesystemusingavacuumpump.Mercuryisthenpushedupthelongthintubeuntilthecontainerandthetubearefull.Themercuryporosimeterworksbymeasuringthecapacitanceofthemercuryinthetube.Asthepressureisincreasedinthechambermoremercuryispushedintotheporesofthepellet.Asthecolumnofmercuryisdecreased,thecapacitancechangesbyacertainamountwhichiscalibratedsothatavolumecanbecalculated.Thepressureinthesystemisincreasedslowlysothatmoremercuryintrudesintosmallerpores.UsingthepressureandWashburnequationtheporesizecanbecalculated.Thus,avolumefromthemeasuredcapacitancecanbeobtainedandcorrelatedtotheporesizecalculatedfromthecapacitance.Theporesizedistributionsaregeneratedinthismanner.RamanSpectroscopyTheoryRamanspectroscopyisalightscatteringtechniquetodeterminethecompositionofmolecules.Alaserisfocusedontoasurface.Thelightistheninelasticallyscatteredaccordingtothebondsofthemolecule.ThisiscalledtheRamaneffect.TheRamaneffectonlyoccursforabout1in10millionincidentphotonsandisthereforeaweaksignal.Inelasticscatteringoccurswhenaphotongainsorlosesenergyfromthevibrationenergyofbondsinamolecule(Eq.4.3).Ifthephotonlosesenergyitwillhaveahigherwavelengththantheexcitinglight.ThisiscalledtheStokeslineandisgenerallywhatismeasured.Ifaphotongainsenergyitwillhavealowerwavelengththantheexciting

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67light.Thisiscalledtheanti-stokeslineandisgenerallyveryweekandhardtodetect.Thechangeinwavelengthofthestokesandanti-stokeslineisrelatedtothevibrationalenergyspacing.Thusthesechangescanbeusedtodirectlymeasurethevibrationalenergiesofthemolecule.Inordertodetecttheseweaksignalsahighpoweredmonochromaticlightsourcesuchasalaserisused.h/in+Evib=h/out (4.3) Thisscatteredlightisdetectedoveraspectrumofwavelengths.Thespectraformaterialsaredifferentbasedontheirbonds.Thiscanbeseeninthespectrafordifferentmaterials.Characteristicpeakswillindicatethepresenceofparticulartypesofmolecules.Ramanspectroscopyalsohasasignalinwhichtherelativeintensitiesofthecharacteristicpeakscanbecorrelatedtotheconcentrationofacertainsubstance.Inordertodothis,spectrummustbetakenfromknownconcentrationsofspeciesofinterest.ProcedureAsampleofpowderispreparedandputintoameltingpointcapillarytube.AcomputerisattachedtotheRamanspectrometer.AprogramcalledOMNICisusedtoadjustthelaserlightsothatthebestsignalisobtained.Thelaserisfocusedontothesampleandthescatteredlightisreflectedtoaspectraldetector.Thissignalcanbemeasuredfordifferentlengthsoftime.OMNICalsoaveragesanumberofsignalswhichcanbevaried.Anumberofotherparametersaffectingstrengthofthelaserandthesignaldetectioncanbechanged.Aspectrumisthenobtainedforeachsample.Characteristicpeaksatcertainwavelengthswillindicatethepresenceofaparticularsubstance.Sometimesthestrengthofthesignalcanalsobecorrelatedtotheconcentrationoftheparticularsubstanceofinterestifcalibratedusingknownconcentrations.

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68ChemicalTestingTheoryChemistrycanbeusedtodeterminetheamountofCaOpresentinthepellets.ThetwomaincomponentsinthepelletsareCaOandCaTiO3.CaOreactswithHBrtoformCaBr2yetCaTiO3doesnotreactwithHBrorH2O.ThepercentageofCaOcanbefoundusingthemolecularweightsCaOandCaBr2andthedifferenceisweightafterareactionwithHBrandevaporationofvolatiles.ProcedureSamplesweremadeofpowderproducedwithmodifiedchemistryandheatingprocedures.Eachsamplewasplacedinasamplecontainerandweighed.Anexcessmolaramountofhydrobromicacidwasaddedtoeachcontainerviaa48%byweightsolutionofhydrobromicacidinwater.Themixtureswerethensubjectedto80Cheatingfor18hours.Theheatingtemperaturewasincreasedto100Cfor4hrsandto200Cforanadditional2hours.Allthechemicalswerevolatileexceptforthecalciumcompounds.TheamountofCaOcanbequantifiedbyfindingthechangeinweightresultingfromtheaddedHBrsolutionbecauseCaTiO3doesnotreactwithHBr.TheextentofthereactionwasdeterminedbyusinglaboratorygradeCaOandperformingthesameprocedure.Theextentofthereactionwasfoundtobe98%.ThisprocedurewasusedtodeterminetheamountofCaOineachsample.Anerrorofabout5%isestimatedusingthisprocedure.Though,smallamountsofCaCO3andTiO2canbepresentinthepelletmostofitiscomposedofCaOandCaTiO3.Thus,aftertheCaOiscalculatedtheamountofCaTiO3canbeapproximatedastheremainderofthecomposition.

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69CHAPTER5EVALUATIONOFPARAMETERSTheeffectofvariousparametersonthepelletcharacteristicstheporosity,thechemicalcomposition,andthestrengthwasstudiedtodevelopthemoldingandheatingprocedures.TheparametersarelistedinTable5.1andareassociatedwiththechemicalformulation,moldingprocedure,andpelletheattreatment.Correlationshavebeenmadebetweenproceduralparametersandtheresultantcharacteristicsofthepellet.Theoptimumprocedurehasbeenchosenbasedonthesecorrelations.Thesecorrelationsandtheoptimumprocedureparametersarepresentedinthischapter.CorrelationsfromOriginalChemistryTheoriginalchemistrywashelpfulfordeterminingageneralrangeofparametersfortheheatingproceduresandmoldingprocedures.However,thisprocedurehadtobemodifiedtoattainthedesiredcompositioninthepellets.Figure5.1isadiagramthatillustrateshowtheparameterswereevaluatedbasedontheresultingcharacteristics.WithineachofthesegeneralcategoriesdescribingtheprocedurethereareparameterswhichcanbeseeninTable5.1.Theparameterswitha(1)areoneswhichwerevariedtocharacterizethepelletsusingtheoriginalchemistry.Likewise,a(2)indicatesparametersforthemodifiedchemistry.An(M)indicatestheparameterswhichwerechangedasadirectresultoffeedbackfromthecharacteristicsoftheresultingpellets.Parameterswithoutanyofthesedesignationswereestablishedintheoriginalprocedureandnotsignificantlychangedorvariedtoinvestigatehowthecharacteristicsofthepelletchanged.

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70Table5.1ParametersintheMainCategoriesShowninFigure5.1 Chemistry(M) Molding HeatingProcedures Ca/TiRatio(2)(M)CompressionForce(1)(M)DryingTime&Temp.pHBinderAdditive(1)PreheatingTime&Temp(M)Water/Ca(M)MaxSinteringTime&Temp.(1)(2)Ethanol/Ca(M)Temp.RampingScheme(M) CondensationTimeandTemp. FinalMoldingandHeatingProceduresPelletHeatingProcedureStrengthComposition Strength,MicroporosityStrength OriginalChemistryPelletMoldingProcedure Figure5.1FlowDiagramIndicatingHowCharacteristicsWereUsedasFeedbacktoModifytheParameterstoArriveattheFinalProceduresMoldingProcedure:StrengthThestrengthwasqualitativelybeanalyzed.Iftheextrudedpelletfellapartitwasdeemedtooweak.Mostofthepelletsformulatedusingtheoriginalchemistryrequiredacompressionof1.0metrictontoensurewholepellets.HeatingProcedure:StrengthandMicroporosityTheheatingprocedureswereevaluatedbasedonthestrengthandthemicroporosityofthepelletafterheattreatment.Thepreheatingstepwasaddedtoimprovestrengthasdescribedinchapter3.Themeritsoftheheatingprocedureswerealsoevaluatedbased

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71onthestrengthofthepelletsafterheating.Thepelletsremainedintactwithnosignificantcrackingduringheating.Highertemperaturesledtosinteringandcreatedstrongerpellets.Thiswasqualitativecomparisonasnoquantitativestrengthtesthasbeendone.Themaximumtemperatureoftheheatinghadadirectimpactonthemicroporosityofthesamples.ThecumulativeporevolumewasmeasuredusingnitrogenadsorptioninconjunctionwithaBJHcorrelationandisplottedagainstthemaximumsinteringtemperatureinFigure5.2.Thedatafitacorrelationy=0.0012x2-2.6701x+1433.7wherexisthemaximumsinteringtemperatureandyisthecumulativeporevolume.Themicroporositydecreaseddrasticallyfrommaximumtemperaturesbetween700Cand1000Cforpelletswiththesamechemistryandmoldingprocedures.At700Ctheporosityis0.171cc/gwhichdropsdownto0.006cc/gwhenthesinteringtemperatureisincreasedto1000C.Theintermediatetemperaturesof800Cand900Cshowthedecreasingtrend.Asinteringtemperatureof800Cwaschosenforinvestigationwiththepelletscreatedusingthenewchemistry.Thistemperaturegaveareasonablestrengthtothepelletswithoutdrasticlossinporosity. Figure5.2SpecificCumulativeMicroporeVolumevs.MaximumSinteringTemperature

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72Chemistry:ChemicalCompositionRamanSpectroscopyidentifiedthecompositionofthefirstpellets.TwopelletsweretestedandfoundtocloselyresembletheRamanspectraforrutileandanatase-TiO2.Thisconfirmedsuspicionsthattheoriginalchemistrydidnotformthedesirednetwork.Figure5.3showstheRamanspectrafromtwopelletsmadeusingtheoriginalchemistryalongwiththespectraforbothanataseandrutileTiO2wherethey-axisistheintensity(Int)oflightforthatwavelength.Pellet1appearstobemostlyanataseTiO2.Fourmatchinganatasepeakscanbeseenfromlefttoright.However,therearenorutilepeaks.ThespectraforthesecondpellethaspeaksofbothanataseandrutileTiO2indicatingthepresenceofbothphasesofTiO2inthepellet.Thisprobablyoccurredduetothedifferentheatingproceduresthispelletunderwent.PeaksforCaOandCaTiO3aremarkedlyabsentinthesespectra.BecauseoftheminuteamountofCaOtheoriginalchemicalprocedureshadtobemodified. TiO2Anat TiO2Anatase TiO2Anatase TiO2Anatase Pellet1 Pellet2 TiO2Rutile TiO2Rutile 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 Int 200 300 400 500 600 Ramanshift(cm-1)Figure5.3RamanShiftSpectraofAnataseandRutileTiO2andTwoRepresentativePelletsMadeUsingtheOriginalChemistry

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73CorrelationsfromModifiedChemistryCorrelationsweremadebetweenthecharacteristicsofthenewpellets(madeusingthemodifiedchemistry)andtheproceduralparameters.Figure5.4illustrateshowthecharacteristicsareusedtoevaluatetheparametersinthismodifiedprocedure.RefertoTable5.1forparameterswithineachmainproceduralstep. Strength,Macroporosity,Composition FinalMolding,Heating,andChemicalProceduresPelletHeatingProcedure Strength,Macroporosity Strength Strength PelletMoldingProcedureModifiedChemistry Figure5.4VisualFlowDiagramofHowCharacteristicswereUsedasFeedbacktoModifytheParametersUsingtheModifiedChemistryMoldingProcedure:StrengthandMacroporosityThenewpelletsrequiredacompressionforceofonly0.25metrictonstoholdtogetherascomparedto1metrictonforthepreviouspellets.Thisimprovementisconsiderablebecauseincreasedstrengthatlowercompressionwillresultingreaterporosityforthesepellets.

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74Acomparisonbetweennewpelletscompressedat0.5metrictonsand0.25metrictonswasconducted.Thepelletsweremadewitha2to1ratiobetweencalciumandtitaniumandheatedto800Cusingthesameheatingscheme.Thesizeoftheporesseemstoremaininthesamerangeindicatedbythedifferentialdistributionwhichpeaksaround100nm.However,thespecificcumulativeporevolumeforthepelletswasapproximately0.15cc/glessatthe0.5metrictoncompression.ThisisshowninFigure5.5bythesmoothcurvesincreasingrighttolefttoamaximumat10nm.ForreferencealargerversionofthisgraphcanbefoundinAppendixF,(FigureF.2). CumulativeandDifferentialPoreVolumeDistributions00.10.20.30.40.50.60.7101001000PoreDiameter[nm] CumulativeSpecificPoreVolume[cc/g] 00.0010.0020.0030.0040.0050.006DifferentialSpecificPoreVolume[cc/g] 0.5MTCumulative 0.25MTCumulative 0.5MTDifferential 0.25MTDifferential 10per.Mov.Avg.(0.5MTDifferential) 10per.Mov.Avg.(0.25MTDifferential) Figure5.5ComparisonofCumulativeandDifferentialSpecificPoreVolumeDistributionforNewPelletsCompressedat0.25and0.5MetricTons.Chemistry:Macroporosity,Microporosity,Composition,andstrengthUsingthemodifiedchemistryanetworkofCaOandCaTiO3wassynthesized.AnattemptwasmadetouseRamanSpectroscopytoverifytheexistenceofCaTiO3and

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75CaO.AtfirstthesamplespectraobtainedwereinconclusiveastheirpeaksdidnotmatcheitherthoseofthepureCaOspectrumorCaTiO3spectrumasexpected.Onepossiblereasonforthismaybeelectricalinteractionthatmayoccurinthesamples.Sincethescaleofmixingusingthealkoxidechemistryisatthemolecularlevel,whichmayaltertheelectronicresponse.ThiswouldaffecttheRamanspectroscopyasituseslightscatteringthatcanbeaffectedbyslightvariationsintheelectricfieldsofthesamples.AppendixE(FigureE.2)showsthecomparisonofasamplemadeusingthemodifiedchemistry,PureCaOandPureCaTiO3.ThesampleswerealsocomparedtospectrafromCaCO3,Ca(OH)2,TiO2-rutile,andTiO2-anatasetoidentifyifanyofthesesubstanceswaspresent.Theredidnotappeartobeanystrongmatchesinthesamplesformulatedwiththenewchemistryandthesecompounds.OnesampledidhaveasmallmatchingpeakwithCaCO3indicatingasmallpercentageofCaCO3(~2-5%).Theflorescenceofthesamplesgeneratebroadpeakswhichhidethespeciesidentifyingpeaks.AsecondattempttousetheRamanspectroscopyrevealedstrongmatchingpeaksforCaTiO3fortwodifferentpelletpowders.Thesepowdersweremadeusinga2to1ratiobetweencalciumandtitaniumandheatedto1000C.Theonlydifferencebetweenthetwopelletswasthetemperatureofpreheating.Pellet1waspreheatedat430Cwhereaspellet2waspreheatedat600C.Figure5.6showsthematchingofthepeaks.MoreRamanshiftspectraarepresentedinappendixEincludingthefullspectraofthepieceshowninFigure5.6.Itshouldalsobenotedthatforthisspectratheintensityvalue(Int)ismeaninglessasthespectrawereoffsetandscaleddifferentlytoshowmatchingpeaks.TherewerenostrongpeaksinthespectramatchingCaO,butanon-fluorescingspectrumforCaOcouldnotbeobtained.

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76 Pellet1 CaTiO3 CaTiO3 Pellet2 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 Int 200 300 400 500 600 Ramanshift(cm-1)Figure5.6RamanShiftSpectraforCaTiO3andTwoSamplePelletsTheexistenceofCaOandCaTiO3inasamplemadefromthemodifiedchemistrywasverifiedthroughX-raydiffraction(XRD)becauseoftheinconclusivedatafromthefirsttryatRamanSpectroscopy.ThesignaturepeaksofCaTiO3andCaOhavebeenidentifiedintheXRDtakenforthissample(Figure5.7).InadditiontotheXRDverification,theamountsofCaOinthepelletswerefoundusingthechemicaltestingproceduredescribedattheendofchapter4.ResultsfromthechemicaltestingprocedurecanbeseeninTable5.2formanydifferentsamples.InTable5.2thevaluesforthe%CaOarecalculatedbasedontheassumptionthatcalciumonlyexistsasCaOandneglectsthepossibilityofCaCO3orCa(OH)2.Theassumptionispooratlowtemperatures.TheexistenceofCaCO3andCa(OH)2isevidentinthehighpercenterrorintheModifiedChemistryPowder2datafortheunheatedand430Cheatedruns.However,thisseemstobeareasonableassumptionwhenthe

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77maximumheatingtemperaturesis1000C.ThetemperaturedrivesthedissociationofanyCa(OH)2orCaCO3thatmaybepresent.Thus,theresultsshowthatthepresenceofCaOisclosetotheexpectedpercentagebasedonthestoichiometricrelationshipsbetweencalciumandtitanium.ThestandardsamplesofCaOandCaTiO3justifythevalidityofthetest.CaOandCaTiO3arewithin2%and3%oftheirtheoreticalvaluesrespectively.TheCaTiO3inthepelletpowdercanalsobeseenunreactedatthebottomofthesamplecontainer.Oneotherpointofinterestisthatthesamplesmadewithpowderfromtheoriginalchemistrydonotindicateanyappreciablereaction.ThisagainconfirmstheminuteamountofCainthesepellets.Table5.2ResultsofQuantitativeChemicalCompositionTestingProcedures SampleDescription Ca/Ti MaxHeatingTemp Exp. Theor. %Error Mod.Chem.Powder11430C9.0%0.0%9.0% Mod.Chem.Powder1 1 430C 8.7% 0.0% 8.7% Mod.Chem.Powder221000C45.4%50.0%9.2% Mod.Chem.Powder2 2 430C 25.5% 50.0% 49.1% Mod.Chem.Powder2 2 unheated 30.7% 50.0% 38.6% Mod.Chem.Powder321000C47.1%50.0%5.8%Mod.Chem.Powder431000C58.7%66.7%12.0%OriginalChem.Powder1~0900C0.6%0.0%0.6%OriginalChem.Powder2~01000C0.3%0.0%0.3%PureCaON/Anone98.3%100.0%1.7%PureCaON/Anone98.0%100.0%2.0% PureCaTiO3 1 none 3.3% 0.0% 3.3% ExperimentalParameters%CaO Theratiosofcalciumtotitaniuminthechemicalformulationwerevariedtodetermineitsaffectonthestrength,composition,macroporosityandmicroporosity.Boththemacroporosityandmicroporositydecreasedwithanincreaseinthecalciumtotitaniumratio.TheseporevolumesarecomparedtothosereportedbySakuraietal.(1995)inFigure5.8.Inordertohaveadirectcomparisontheporevolumewasnormalizedbythevolumeoftherespectivepellets.Spheresof5mmdiameterwereused

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78forSakuraietal.becausethatwasrecordedintheirpapersandcylindersof3/16diameterand5/16lengthwereusedforthiswork.NotethatthemicroporosityinthenewpelletsisgreaterthanthosereportedbySakuraietal.Themacroporosityforthenewpelletshoweverisless.Thisisalittlemisleadinginthatmuchoftheporosityrecordedinthemicroporeswasveryclosetothetransitionbetweenmicroandmacroporesat0.1to0.2microns.ThiscanbeseeninthedifferentialandcumulativedistributionsfortheseratiosinAppendixF,FigureF.1.Theseporescanbemanipulatedbychangingsomeoftheproceduralparameterstoyieldmoremacropores.Graphitewhichwasnotintroducedinourpelletswillalsohelptoincreasetheporosityinthemacroporeregionandmicroporeregion. 20 30 40 50 60 70 802Theta 0 50 100 150 200 250 counts/s CaTiO3CaTiO3CaTiO3CaOCaOCaTiO3CaOCaTiO3CaTiO3CaTiO3CaTiO3CaTiO3CaTiO3CaTiO3CaTiO3CaTiO3CaTiO3CaOCaTiO3 Figure5.7X-rayDiffractionDatawithPeaksVerifyingthePresenceofBothCalciumOxideandCalciumTitanate

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79 00.10.20.30.40.50.60.70.81PoreVolume/PelletVolume[cc/cc] <.5um(Ca2/Ti1) <.5um(Ca3/Ti1) <.5um(Ca4/Ti1) <.5umUT-3 >.5um(Ca2/Ti1) >.5um(Ca3/Ti1) >.5um(Ca4/Ti1) >.5umUT-3Figure5.8ComparisonofMicroporeandMacroporeVolumeofPelletsMadewithRatiosofDifferentCalciumtoTitaniumRatioswithUT-3(Sakuraietal.,1995)PorosityResultsThestrengthofthepelletsgenerallydecreasedwithanincreaseinthecalciumtotitaniumratio.Thepelletsseemedtobemorefragileandhadmorecracksforaratioof3and4(Ca:Ti,molar).Thiswasexpectedbecauseagreaterratiodecreasesthepercentageoftitaniumwhichistheelementwhichformsthesubstratestructure.Whenthepercentoftitaniumisdecreaseditis,therefore,expectedthattheintegritywillalsodecrease.HeatingProcedures:Composition,Strength,andPorosityTheheatingprocedureswereevaluatedbasedonthecharacteristicsofcomposition,strength,andmacroporosity.AcomparisonoftheporositiescanbeseeninFigure5.9(EnlargedasFigureF.3).Thecumulativeanddifferentialspecificporevolumesareshown.Thedifferentialdistributionseemstobeflatterwhen900Cand

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801000Cheatingtemperaturewereused.Thisindicatesthattheporevolumeisdistributedamongstagreaterrangeofporesizes.The800Cheatedpelletshadamuchnarrowerporevolumedistribution.Theporevolumewashighestin800Cheatedpellet.However,themaximumdifferenceinthecumulativeporevolume,isonlyabout0.05cc/gbetweenthe800Cand900Cheatedpellets.Thesepelletsuseda2to1ratiobetweencalciumandtitaniumandwerecompressedintopelletsusinga0.25metrictonsforce.Allthepelletswerealsopreheatedat430C.The900Cand1000Cpelletswereactuallyweakerthanthe800Cpelletinthiscase.ThereasonforthisisbelievedtobeCa(OH)2and/orCaCO3dissociatingattheirdissociatingtemperaturesof580Cand898Crespectively..Twoslightmodificationstotheheatingprocessweremade.1.Thepreheattemperaturewasraisedto600Ctoeliminateanycalciumhydroxidethatmightbeinthepellet.2.Theramptimefrom700Ctothemaximumsinteringtemperaturewasextendedto2hourstoslowtheformationandescapeofcarbondioxideascalciumcarbonatedissociates.Thepelletsmadeusingthesemodificationsseemedtobejustasstrongifnotstrongerthanthe800Cheatedpellets.Thecompositionofthepelletswasquantitativelymeasuredusingchemistrybytheprocedureoutlinedattheendofchapter4.Table5.2ShowsvaluesfordifferentratiosandheatingschemesOptimumParametersTherearemanyparameterswhichcaneffectthecharacteristicsofthepellets.Themostimportantcharacteristicsreactivityanddegradationhaveyettobestudied.Whatmayseemtheoptimumbasedonthecharacteristicsofstrength,porosity,andcompositionmaynotevenlastonecycleinareactor.Evenwithjustthecharacteristics

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81exploredinthisworkitisdifficulttoweighteachcharacteristicastheyareinterdependent.WiththeseconsiderationsTable5.3presentswhatarethoughttobetheoptimumofthevariedparametersbasedonthedatacollected. 00.10.20.30.40.50.60.710100100010000PoreDiameter[nm]CumulativeSpecificPoreVolume[cc/g]00.0010.0020.0030.0040.0050.0060.007DifferentialSpecificPoreVolume[cc/g] 800CDifferential 1000CCumulative 900CCumulative 800CCumulative 1000CDifferential 900CDifferential 10per.Mov.Avg.(800CCumulative) 10per.Mov.Avg.(1000CDifferential) 10per.Mov.Avg.(900CDifferential)Figure5.9ComparisonofCumulativeandDifferentialSpecificPoreVolumeDistributionforNewPelletsSinteredatDifferentTemperatures.Table5.3OptimumParametersUseModifiedChemistryScheme2Ca:1TiPrecursorPreheatingTemp.600CMoldingCompressionForce0.25MTSinteringTemperature900C SlowTemp.RampingScheme 2hrs Themodifiedchemistryisusedtocreatethepellets.A2to1ratiobetweencalciumandtitaniumwaschosen.ThiswasinlargeparttoensurethatadequateCaTiO3networkisgeneratedtomakethepelletsstructurestrongtoendurethereactorenvironment.Thepreheatingtemperaturewastoeliminatevolatilesthatmayaffectthe

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82strengthwhenthepelletisheattreated.Thecompressionforcewaspickedbecauseitisthoughtthatitwouldhelptheporosityandgiveanacceptablestrength.The900Csinteringwaschosenbecauseitstrengthensthepelletbutdoesnotdecreasetheporositygreatly.ItisalsothoughtthatthiswoulddissociateanyCaCO3sothattheCaOcontentwouldbeincreased.Thisworkhasfocusedoncylindricalpellets,thoughtherearemanydifferentshapesandsizesofpelletsthatareusedinindustry.Thequestionhasbeenraised,Canthesecharacteristicsbemaintainedifadifferentpelletshapeorsizeisused?Thisquestioncannotbeansweredsimply.Somecharacteristicswillalwaysbemaintainedwhileotherswillvaryslightlydependingonthepelletmakingprocedure.Thecompositionforexamplewillalwaysremainthesameifthesamechemistryandheatingproceduresareused.Thestrengthandporosity,however,maychangeindifferentpelletshapesandsizes.Theconsolidationforceusedtocompressthepelletswillgreatlyaffectthemacroporosityandthestrengthasshownearlierinthischapter.Theshapecouldalsocontributetothemacroporosity.Generally,macroporesarefoundclosertothesurfaceofthepellets.Thismeansthattheshapeswithalargersurfaceareatovolumeratioyouwouldexpecttohavegreatermacroporosityperunitvolume.Thesizeofthepelletalsomakesadifferenceintheporosity.Porecloggingandsinteringoccurinthepelletsbecauseoftheproceduralsteps.Becauseofthislessporesareaccessiblefurtherintothepellet.Thus,ifpelletswiththesamesurfaceareatovolumeratiosanddifferentvolumesarecomparedtheonewiththesmallervolumewillyieldahigherspecificporevolume.Thestrengthofthepelletsobviouslycandependonshape.Forinstanceanannularpelletwillprobablynotbeasstrongasacylindricalone.Therearemanyestablished

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83techniquesforcreatingthesepelletsandtheonlytruewaytoseetheeffectofanewshapeand/ormoldingprocedureonthecharacteristicsistostudythem.

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84CHAPTER6RECOMMENDATIONSFORFUTUREWORKTeoetal.(2005)encouragethosestudyingtheUT-3thermochemicalcycleandotherthermochemicalcyclestoexaminewhetheritisworthinvestigation.TheiranalysissuggestsamuchlowerefficiencythanreportedbytheoriginalUT-3researchers.Basedonthisanalysisitseemsresearcheffortshouldpossiblybefocusedelsewhere.Though,thisviewisheldbysomeintheresearchcommunity,theremayyetbesomepotentialfortheUT-3thermochemicalcycle.Themainlimitingfactorontheefficiencyofthecyclearethehighoperatingtemperaturesatwhichthereactionstakeplace.ImprovingthechemistryofthesystemusingsomesortofcatalystmaybeanecessarysteptomaketheUT-3thermochemicalcyclepractical.Acatalystthatwouldlowertheactivationenergyofthereactionsshouldbesought.Assumingsuchacatalystexists,thismayimprovethethermodynamicsofthesystemenoughtowarrantacloserlookatthefeasibilityoftheUT-3thermochemicalcycle.MuchworkcanbedoneontheUT-3thermochemicalcycleinadditiontofindingacatalyst.ThescopeofthesuggestedfutureworkwillfocusonthedevelopmentoftheCaOpelletsandthereactionsthatoccurinthem.Muchotherworkcanbedoneintheareasmentionedinchapter1inthehistoryoftheUT-3thermochemicalcyclesection.Thesubsequentworkshouldfinishcharacterizingthecalciumoxidepellets.Thereactivity,degradation,andcyclicstrengthshouldbeinvestigatedthroughthebrominationreaction.Theparametersofthepelletproductionproceduremayhavetobemodifiedinordertoobtaindesiredcharacteristics.Afterthepelletshavebeenstudiedon

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85anindividualbasiswithsatisfactoryresultsaproceduretomoldthepelletsinamoresophisticatedmannershouldbedeveloped.Theprocedureandequipmentshouldallowformassproductionofpelletsquicklysothatenoughforasmallfixedbedreactorcanbemade.Alargenumberofpelletsshouldbemadeandplacedtogetherinafixedbedreactortodeterminehowthepelletswillperform.ShortTermPlanInvestigationintoReactivityOneofthemostimportantcharacteristicsisthereactivity.Thereactionratesandconversionofthetwocalciumbasedreactionsshouldbedeterminedthroughexperimentationandcomparedtothosereportedintheliterature.Theseshouldbothbestudiedandaninvestigationofmethodstoincreaseconversionorreactionratesshouldbedone.Reactivityshouldbemeasuredandcorrelatedtodifferentoperatingparametersincludingtemperature,pressure,gaseousreactantconcentration,andflowrate.ReactionratesThelimitingreactionrateshouldbedetermined.Theratefoundshouldbecomparedtothatintheliterature.Thepelletproductionproceduremayneedtobemodifiedtoincreasethereactionrates.Creativestrategiestoimprovethekineticratesshouldbeexplored.Itshouldbedeterminedifthediffusiontoandfromtheinternalsurfaceofthepelletorthesurfacereactionitselfisthelimitingstepinthereaction.Ifitis,modificationsinthepelletsshouldbemadethatwillimprovediffusion.Theshapeandsizeofthepelletscouldbechangedtodecreasethethicknesswhichthegaseousreactantsandproductshavetodiffuse.Increasingthemacroporositywillalsohelpwithdiffusionrates.Increasingmicroporositytoincreasetheamountofavailablereactionsitescouldalsohelpthereactionkinetics.Ifthelimitingrateisthesurfacereactiononly

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86afewthingscanbedone.Concentrationofreactantsshouldbeincreasedinthepelletsevenifaslightcompromiseinporosityissacrificed.Littlemodificationtothepelletcanbedonebeyondthis.Ifthereisnolimitingstepbutratherthelimitisacombinationofsurfacereactionanddiffusion,theoptimumcharacteristicsshouldbefound.Itmaybebeneficialtofirstmakethepelletsporousenoughtoeliminatethediffusionpartofthelimit.Ifsuccessfulthereactantpercentshouldbeincreaseduntilitstartsaffectingdiffusionsignificantly.Inthiswaythereactionratescanbeincreased.ConversionConversionisalsoaffectedbycompositionandporosity.Porosityallowsformoresitesforreactionsandmoreavailabilitytothereactant.Thisresultsinagreaterconversion.Ahigherconcentrationofthesolidreactantcanalsoincreasethegasphaseconversionifnottheconversionwithinthepellet.InvestigationofDegradationTheperformanceofthepelletsshouldbeinvestigatedoveranumberofcyclestoseeifthereactivitydegradesfromonecycletothenext.ThisisveryimportantduetothecyclicnatureoftheUT-3thermochemicalprocess.Ifapelletonlyhasa1%conversionafterfivecyclesitwillnotbepracticalfortheUT-3cycle.Thesepelletsneedtohavearelativelyconstantcyclicreactivityinordertomaketheprocessviable.Thetwomaincausesofdegradationarereductioninstructuralstrengthwitheachcycleandsinteringofparticles.Bothoftheseprocesseseitherclogorcollapseporesreducingporeareatowhichthegaseousreactantscanaccess.Thisultimatelyreducesreactivityoveranumberofcycles.

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87InvestigationofCyclicStrengthAnothercharacteristicthatcouldbequantifiedisthestructuralstrengthofthepellet.Thisshouldbequantifiedbeforeandafterasetofcyclestodeterminehowthestrengthvarieswiththenumberofcycles.Theporositycanbedrasticallyreducedifthepelletsdonotmaintaintheirstructure.CreativeEngineeringThepelletsmaybeimproveduponwithsomecreativeengineering.Asmentionedaboveshapeandsizeofthepelletscanbemodified.Alsodifferentchemistrycanbeemployedtoyieldbettercharacteristics.Athinsurfacecoatingoftitaniamaybeaddedtoincreasestructuralstrength.Thesearejustafewofnumberofstrategiesthatcanbetaken.Ifthepelletsdonothaveacceptablecharacteristicsotherportionsoftheresearchmaynotbeworthwhile.LongTermPlanMassProductionofPelletsInordertostudythepelletsinafixedbedreactoralargenumberofpelletshavetobemade.Thepresentprocedureisslowandunsophisticated.Onceacquaintedwiththeproceduretheprocesstakesapproximate5minutesperpelletafterthepowderhasbeenmade.Thepelletsoftenarenotuniformshapeandsometimesbreak.Forafixedbedreactorwithandinsidediameterof4cmandadesiredheightof10cm,approximately460pelletswouldbeneededifthepackingorderwasonly50%.Thiswouldtakeapproximately39hourstomakethepellets.Obviously,amoresophisticatedprocedureisnecessarytostudythepelletsinareactor.

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88PelletPerformanceinaFixedBedReactorOncethepelletsarefoundtohaveacceptablecharacteristicsalargenumberofpelletsshouldbeproducedandtestedinasmallfixedbedreactortoinvestigatethesystemperformance.Studiesshouldbedonetoevaluatethebulkcharacteristicsofthepellets.Reactivity,conversionanddegradationarethecharacteristicsonwhichanalysisshouldbebased.Theidealoperatingparametersshouldbefoundincludingtemperature,pressure,gaseousreactantconcentration,andflowrate.Correlationsshouldbefoundbetweenreactivityandoperatingparameters.

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89CHAPTER7SUMMARYANDCONCLUSIONSAprocedurewasdevelopedforproductionofthecalciumoxidesolidreactantsfortheUT-3thermochemicalcycle.Theproceduredevelopedincludesmethodsofchemicalformulation,drying,molding,andheattreatment.Thechemicalprocedureshavebeenchangedsignificantlyinordertoobtainthecorrectcompositionoftheprecursors.Preheatingprocedureswereaddedtothedryingprocedurestoeliminatevolatilesbreakingthepelletsformedwiththeprecursors.Amoldforthemoldingprocedurewasfabricated,tested,andredesignedtoproduceadependabletooltoproducepellets.Areliablemoldingprocedurewasdevelopedtomakethepellets.Aheatingschemewascreatedtostrengthenthepelletsusingtemperaturesabovethemaximumoperatingtemperaturesofthereactionsof760C.Analyticaltechniqueswereusedtoassessthisprocedurebymeasuringtheporosityandcompositionofthepellets.Porositymeasurementtoolsthatwereusedarenitrogenadsorptionandmercuryporosimetry.CompositiontoolsincludeX-raydiffraction,RamanSpectroscopy,andchemicaltests.Strengthwasalsoevaluatedquantitatively.Correlationsbetweentheparametersandthecharacteristicsofcomposition,porosity,andstrengthwereusedtodeterminetheoptimumparametersfortheprocedure.Thesuggestedoptimumparametersareasfollows:1.Usethemodifiedchemistrywitha2to1calciumtotitaniumratio

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902.Useapreheatingtemperatureof600C.3.Useamoldingcompressionforceof0.25metrictons4.Sinterthepelletsat900Cusingtheslowtemperaturerampingscheme.Theseparametersmaychangesignificantlybasedonfurthercharacterizationofthereactivityanddegradationofthepelletsinthereactorenvironment.FurtherstudiesarenecessarytorealizethepotentialoftheUT-3thermochemicalcycle.Thesestudiesshouldincludefurthercharacterizationofthecalciumoxidepellets,asearchforacatalystforthereactions,massscaleproductionofpellets,andbulkcharacterizationofthepelletsinafixedbedreactor.

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91APPENDIXACHEMICALPROPERTIESTableA.1ChemicalPropertiesofVariousSolidandLiquidsUsedinThisProject ChemicalName Chemical Color BP/MP Density MW CalciumMetalCaBlack/Gray840C1.640.08CalciumBromideCaBr2White806C1.7199.9CalciumCarbonateCaCO3White898C**2.8100CalciumOxideCaOWhite4658C3.356CalciumHydroxideCa(OH)2White580C**2.2474CalciumTitanateCaTiO3LightBrown1975C4.1136TitaniumOxide-anatase-TiO2White1855C3.880 TitaniumOxide-rutile TiO2 White 3000C 4.2 80 EthanolC2H5OHcolorless79C0.846DionizedWaterH2Ocolorless100C118TitaniumIsopropoxideTi(C3H7O)4colorless232C0.962284BromideBr2darkbrown59C3.11160 HydrobromicAcid HBr darkorange -66.8C 80.912 LIQUIDS/VOLATILESSOLIDS

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92APPENDIXBRAMANSPECTROMETERANicoletMagna760BenchwithSpectraTechContinuumIRMicroscropeandFTRamanmodulewasused.Belowisapictureofthemodule.TheRamanSpectraweretakenwithalaserintensityof1.06mWandagainof4.Powdersofeachpellettypewerepushedintomeltingpointcapillarytubesandafasteningpiecedesignedtoholdthemwasused. FigureB.1FTRamanModule

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93 FigureB.1InsideofFTRamanModule

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94APPENDIXCPELLETMAKINGPROCEDURESOriginalChemistry1.WeighXgramsofCalcium2.MeasureYmLofEthanol3.Putbothethanolandcalciuminlargebeakeralongwithamagneticstirrod.4.Coverthesolutionwithplasticusingrubberbandstosecurelyfasten5.Putmixtureonamagneticstirrerandstirfor10days6.After10daysthemixtureshouldbeawhitecloudymixture(ifmoretimeisneededstirlonger).IfpossibleletalltheCametalreact(blackpieces)7.MeasureY*18/40mLoftitaniumisopropoxideandaddtomixture,stir5min8.MeasureY*12/40mLofdionizedwaterandaddtomixture,stir5min9.Pourcontentsofbeakerintoacontainerorcontainerswithlargesurfaceareatodryovernight(preferably~1inheightorless)10.LeavefumehoodfanonovernightModifiedChemistry1.CleanandDryflask,condenser,andotherequipment.a.Wipepetroleumjellyoutwithapapertowelwithacetoneonit.b.Washwithwaterandbrushingoutusingabrush.c.Washoutwithdionizedwaterafterathoroughrinse.d.Aboutevery10runsanacidbathcleaningshouldbedonetodissolveandresiduefromthesideoftheflask.

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952.Thecalciumsampleismeasuredontheelectronicscaleandthendroppedintotheflaskthroughtheoutletwiththenitrogenandthermometer.3.Jointstocondenserandadaptorarecoatedwithathinlayerofpetroleumjellytopreventseizing.Thenthejointsandstopperareputinplace.(MAKESURETOCOVERALLRUBBER,ORDONOTUSITASITAFFECTSTHECHEMISTRY)4.Thenitrogenvalvesareopenedtoallowaverysmallflowtotheflask.5.Watertothecondenseristurnedon.(orcondenserisfilledwithwater)6.Wait5minutesfornitrogentopurgesystem.7.Anhydronousethanolisextractedbysyringefromitscontaineranddischargedintothesystemthroughthesiliconsepta.8.Theheateristurnedontoraisethetemperatureofthemixturetobetween72Cand76C.Anoticeablereactionoccursinthistemperaturerange.9.Anequilibriumpointisfoundsothatthetemperatureandthenitrogensettingsaresuchthatthetemperatureremains72C-76C.10.Themixtureisdilutedusingthesameamountofanhydronousethanolasinstep5.11.Titaniumisopropoxideisextractedfromitscontainerviasyringe.Thecorrectproportionisinjectedintotheflaskagainthroughanewholeinthesepta.12.Themixtureisheatedbetween72Cand76Cfor30minutes(1hour).13.Asolutionofethanolanddionizedwaterismadeinabeaker.14.Asyringeisusedtoinsertthewaterethanolsolutionintotheflaskinordertomaintainanoxygenfreeenvironment.Areactionoccursimmediatelycausingmostofthemixturetoturnwhiteincolor.15.Theliquorwasheatedfor1hourandthenpouredintoapetridish.TableC.1ChemicalRatiosUsedinModifiedChemistry Step# Chemical Ammount MolarRatio(toCa) 2Calcium.6grams17Anhydronousethanol30mL3510Anhydronousethanol0-10mL0-1211TitaniumIsopropoxide2.2/1.5/1.1mL1/2or1/3or1/4 14 20%WaterinEthanolSol. 1.8in7.2mL 6.7in6.2

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96DryingandPreheating16.Theliquorwasleftfor18to20hoursunderanexhaustingfumehoodtodrybyevaporation.Thepowderwasmostlydrybuthadnoticeablemoisture.17.Placesomeofthepowderintohangingcrucibleandputitinfurnace18.Setfurnacetemperatureto430Cfor1hour(Thisremovesanyvolatilesthatmaybepresent)19.Takehangingcrucibleoutoffurnaceusingclamp(BECAREFULVERYHOT)20.Placehangingcrucibleonaluminumplatetocoolfor5minutes21.DumpcontentsofcrucibleintoaPetridish22.(Startotherheatingproceduresifnecessary)23.Molding24.Takebasemoldandputitonsteelplateonthecounter25.Takeasmallamountofpowderfromthepetridishandputitinthebasemoldhole.26.Compactthepowderusingaplungerbyhand.(Addcaptoplungerandcompress)27.Addmorepowder28.Repeatsteps20and21untilbottomofplungerwithcapjustbarelypenetratesintothemold29.Properlyalignsteelplate,basemold,plunger,andcapandplaceonthehydraulicpressplatform30.Pumppressuntilresistanceisfelt.31.Watchforcemeterandcontinuetopumpuntildesiredforce.(recommend~.25MTfornewchemistry)32.Watchtheforcemeterandholdtheforceatdesiredforcefor1minutebyslightincreaseinforceaspowderslowlycompacts(Becarefulnottooverloadtheplungerasitwillyieldtheplungerandthebasemold)33.Takeoffassembledmoldandseparatebothcapandplungerandmold(mayneedpliers,butshouldnotbedifficultwithpliers)34.Insertlongerplungerintocapandassemblewithbasemold

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9735.Fliptheassemblysothatthecapisonthebottom.36.Placethehollowcylinderontopsoitsholeisconcentricwiththeholeinthebasemold.37.Placetheassemblyonthehydraulicpresssothatthehollowcylinderisconcentricwithboththeholeinthebasemoldandtheringsonthetopplateofthehydraulicpress.38.Slowlypumpthepresssothatthepelletispushedintothehollowcylinderonthetopofthemold.39.Carefullyremovetheassemblyandtakethehollowcylinderoffvertically.40.Youshouldhaveasolidpelletwithaheightabouthalfofthebasemold41.HeatingProcedures42.Aprogramforthefurnacewasmade(consultATSFurnaceControllerforprocedure)a.Tune-Last-YesTuneModeb.ParameterCheckmultipletimesuntilRampandSoakisselectedc.YesProgramparametersusingarrowkeysupanddownuseparameterchecktogotonextparameterd.Select1cycleandhitNOwhenassuredsoakisdisplayede.EndTuneshouldappear.HitTUNE/Returnandtheprogramissaved.f.PressSTARTtostarttheprogram43.Pelletswereplaceinthequartzcrucibleonthequartzhanger.44.Thequartzhangerwasplaceintothefurnace.45.Thefurnaceprogramwassettorun.46.Thepelletsarecarefullytakenoutofthefurnaceaftertheruniscomplete.47.Thepelletswereweighedusingtheelectronicscale48.Thepelletswereputinpetridisheswhichwerelabeled.

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98APPENDIXDPELLETCHARACTERIZATIONPROCEDURESNitrogenAdsorptionOutgassingProcedure49.Placethelargesamplecellonscaleandtarescale50.Putpelletsinsamplecellandplaceonscale51.Recordmassofpellets52.TakesamplecellwithpelletsinsidetoQuantachromeNOVA1200machine53.Makesurenooneisrunningasampleintheanalysisstation54.Usekeypadtoloadoutgassera.Press3foroutgasstationsb.Press1forloadoutgasserc.Press1forvacuumoutgasd.Themachinewillpressurizethesystemandthenyouwillbeinstructedtoputsamplecellontheoutgasstation55.Unscrewandtakeofftheplugando-ringscrewassembly56.Putplugwiththeotherplugstotheside57.Putheatingmantleoncellandthensecurewithmetalclip58.Puttheo-ringscrewassemblyonthecell59.Movethewholeunit(samplecell,mantle,screwassembly)totheoutgasstation.60.Secureassemblybyscrewingtheo-ringscrewassemblyintotheoutgasstation.61.Hitanykeyonthekeypadtocontinuetooutgas

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9962.Turnontheheatingmantleandsetitto200C63.Thesamplewillbeoutgaseduntilyoumanuallyinterruptit.Generally,thesampleswereoutgassedovernight.64.Gotothekeypada.Press3foroutgasserb.Press2forunloadoutgasserc.Thesystemwillpressurizeandwillinstructyoutoremovethesamplecell.65.Removethesamplecellbyunscrewingtheo-ringscrewassembly66.Replacethepluginplaceofthesamplecellassemblyandrepeatstep11and1267.HitanykeyonthekeypadandtheNOVAwillevacuatethesystemFullIsothermAnalysisProcedure68.HaveNOVA1200Disk,OutgassedSample,andmassofsampleready69.PutDiskintothediskdriveoftheNOVA120070.Gotokeypada.Press2foranalyzesampleb.Itwillpressurizesystemandinstructyoutoplacesampleontheanalysisstation71.Takeoffplugando-ringscrewassembly72.Carefullyplacespacerinthesamplecell73.Securethesamplecellintotheanalysisstationwiththeo-ringscrewassembly74.Takeoutthesmallplugbehindtheanalysisstation.Thisgivesthemachineareferencefortheambientpressure.75.Fillthelargedewarwithliquidnitrogenandrotatethestanddothedewarisunderthesamplecell76.Gotokeypada.Pressanykeytocontinue

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100b.Namethesample(EnterDate)c.EnterUserID(enter1orwhatevernumber)d.Inputthesamplemassandpressentere.Press0tomeasurethedensityofthematerialf.EnterCellnumber(62or50forlargecells)g.EnterSetup(50)h.PressEnteruntilAnalysisStart77.Makesuretousethecoverwiththeholeintocoverthedewar78.Thedewarwillraiseautomatically79.Theprocesswilltakeanywherefrom5-10hourstocomplete80.Theanalysiswillbecompletewhenthedewarisloweredandthesystemispressurized81.Thekeypadscreenwillgobacktothemainmenu.82.Atthispointfollowinstructionforremovalofthesampleandreplacementoftheplugoutlinedin17-18oftheoutgassingsection

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101 FigureD.1QuantachromeNOVA1200MachineforNitrogenAdsorptionwithSmallSampleCellandDewar

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102QuantachromeMercuryPorosimeterPoreVolumeswererecordedfromapproximately1psiato60000psia.FillingApparatusProcedure1.Havepelletsandmeasuredmassready2.Turnonvacuumpump3.TurnonMercuryPorosimeter4.Fillthemercurytrapwithliquidnitrogen5.Putpelletsinsmallsamplecell(differentfromBETcell)6.Takevacuumgreaseandputaroundtheedgeofthecell7.Placemetaltoponcellgentlyandtwisttoensureagoodseal8.PlacerubberO-ringsonbottomandtopofthecell.9.PutTefloncasingonthecelltosealthecontainerandtightentheO-ring(HandTightissufficient)10.Unplugthefillingapparatus11.PutMetalsheathonthesamplecell.ThereisanO-ringatthebeginningsoyouhavetoputalittlebittogetitthrough.12.Putassemblyinthefillingapparatus13.Thereisapiecetosecureassembly.Findthisandscrewitontheassemblytolockitinplace.14.Attachthealligatorcliptotheleadonthebackofsecuringpiece.15.Turnthevalvetovacuumandslowlyopentheratecontrolvalvetograduallyreducethepressureinthefillingapparatus16.ChangethecontrolknobonthevolumetoFA(fillingapparatus).Alsoadjustthecalibrationfrom296to317.17.Unplugthecordwithtothepressuresection.PlugitintotheFA.18.Zeroboththepressureandthevolumecontrol

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10319.Checkthepressureinthefillingapparatus.Adjustthevalvetoallowforafasterflowrate.20.Afterthepressureislessthen50mmofHgclosetheratecontrolvalve.21.Adjustthescrewstoponthefillingapparatustoallowthechamberofthefillingapparatustoanglesothatthemercurycanbefilledupthecapillarytube.22.Switchtheflowvalvetotheventposition23.Rezerothevolumeonthemercuryporosimeter24.Slowlyopentheratecontrolvalvetoraisethepressureinthechamberofthefillingapparatuswhilemonitoringthezeroedvolume.25.Assoonasthevolumestartstochangeclosetheratecontrolvalve26.Adjustthechamberofthefillingapparatussothatthecapillarytubeishorizontalandlockitinplaceusingthescrewstop27.Gotothecomputera.C:\Shouldappear,TypeCDPorothenhitreturnb.C:\Poro\shouldappear,typeporo2pcthenhitreturnc.Thisshouldopenaprogram,hitreturn28.ConsultGaryScheifelleforoperationoftheprogram29.StartDataAcquisitiononthecomputerprogram30.Slowlyincreasethepressurebyopeningtheratecontrolvalve31.Onthemonitorthereshouldbeaplotoftheporevolumevs.pressure32.Whenthepressureisapproximately14.7PSIAclosetheratecontrolvalve33.SwitchtheflowcontrolvalvetoPRESSUREandopenthepressureneedlevalve34.Slowlyopentheratecontrolvalvetoincreasethepressureinthechamber35.Themaximumpressureisabout23PSIAclosetheratecontrolvalveatthistime.36.SwitchtheflowcontrolvalvetoVENT

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10437.Slowlyopentheratecontrolvalvetodecreasethepressureinthechamber38.Onceambientpressurehasbeenreachedpresstheendbuttononthekeyboardtofinishtherun39.Atthispointtheassemblycanbetakenoutofthefillingapparatusa.Holdtheendofthefillingchamberwhileunclippingthealligatorclipandunscrewingthesecuringpiece.b.Slidethecellandmetalsheathoutofthechambermakingsuretoalwayspointitupc.Plugthechamber40.Takeoffthemetalsheath.HighPressureProcedure41.Fillthetophalfofacentimeterofthecapillarywithoilviaasyringe,besuretoeliminateanybubbles.Thismayrequireyoutoextractsomemercuryfromthecapillaryviasyringe.Discardthismercuryinthecleancontainerifinfactithasnotbeencontaminatedwithoil.42.PuttheTeflonspacerontheassembly.43.Putthelargemetalsheathontheassembly.44.Placeassemblysotheoilisupintothehighpressurechamber45.Carefully,lowerthetopofthehighpressurechamberintoplace46.Screwthetopofthehighpressurechamberintoplace47.Pressandholdtheoilfillbuttonandwatchtheexcessoilforbubbles.Waituntiltherearenobubblesfor15seconds48.Switchthepressureconnectioncordbacktoitsoriginalposition49.SwitchtheknobonthevolumesectiontoHIGHPRESSUREandadjustthecalibrationto296.50.Zeroboththepressureandthevolume51.Gotothecomputertosettheprogramup

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10552.Pressthestartbuttonwhendirectedtodosobythecomputerprogram.Themachinewillrunautomatically.Justincaseofaccident,beasafedistanceawaywhenthepressureonthemachineisathighpressures.53.Presstheendbuttononthekeyboardwhentherunhasended.54.Savethedatafilestoreportfiles.55.Exitprogrambypressingtheescapekeymultipletimes.56.OnceinDOSfollowthecommandsa.C:\Poro\shouldappear,typeCD..b.C:\shouldappear,typeCDporodatac.C:\Porodatashouldappear,typeDIRd.Thiswillgiveyoualonglist,typecopySA5####*.*A:e.ThiswillcopythefileswiththenameSA5####andanyendingtothefloppydiskdriveforwhichyoushouldhaveadisk FigureD.3QuantachromeMercuryPorosimeterFillingApparatus

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106 FigureD.2QuantachromeMercuryPorosimeter

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APPENDIXFMERCURYPOROSIMETRYDISTRIBUTIONS

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117LISTOFREFERENCESAihara,M.,Nagai,T.,Matsushita,J.,Negishi,Y.,andOhya,H.,2001,DevelopmentofPorousSolidReactantforThermalEnergyStorageandTemperatureUpgradeUsingCarbonation/DecarbonationReaction,AppliedEnergy,Vol.69,pp.225-238.Aihara,M.,Sakurai,M.,Tsutsumi,A.,andYoshida,K.,1992,ReactivityImprovementintheUT-3ThermochemicalHydrogenProductionProcess,InternationalJournalofHydrogenEnergy,Vol.17,No.9,pp.719-723.Aihara,M.,Umida,H.,Tsutsumi,A.,andYoshida,K.,1990,KineticStudyofUT-3ThermochemicalHydrogenProductionProcess,InternationalJournalofHydrogenEnergy,Vol.15,No.1,pp.7-11.Aochi,A.,Tadokoro,T.,Yoshida,K.,Kameyama,H.,Nobue,M.,andYamaguchi,T.,1989,EconomicalandTechnicalEvaluationofUT-3ThermochemicalHydrogenProductionProcessforanIndustrialScalePlant,InternationalJournalofHydrogenEnergy,Vol.14,No.7,pp.421-429.Amir,R.,Sato,T.,YokoYamamoto,K.,Kabe,T.,andKameyama,H.,1992,DesignofSolidReactantsandReactionKineticsConcerningtheIronCompoundsintheUT-3ThermochemicalCycle,InternationalJournalofHydrogenEnergy,Vol.17,No.10,pp.783-788.Amir,R.,Shiizaki,S.,Yamamoto,K.,Kabe,T.,andKameyama,H.,1993,DesignDevelopmentofIronSolidReactantsintheUT-3WaterDecompositionCycleBasedonCeramicSupportMaterials,InternationalJournalofHydrogenEnergy,Vol.18,No.4,pp.283-286.Barrett,E.P.,Joyner,L.G.,andHalenda,P.P.,1951,TheDeterminationofPoreVolumeandAreaDistributionsinPorousSubstances.I.ComputationsfromNitrogenIsotherms,JournaloftheAmericanChemicalSociety,Vol.73,pp.373-380.Brinker,J.C.andScherer,G.W.,Sol-GelScience:ThePhysicsandChemistryofSol-GelProcessing,NewYork,AcademicPressInc.Brinker,J.C.,Sehgal,R.,Hietala,S.L.,Desphande,R.,Smith,D.M.,Loy,D.,andAshley,C.S.,1994,JournalofMembraneScience,Vol.94,p.85.

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118Brown,L.,Besenbruch,G.,Schultz,K.,Showalter,S.,Marshall,A.,Pickard,P.,andFunk,J.,2002,HighEfficiencyGenerationofHydrogenFuelsUsingThermochemicalCyclesandNuclearPower,AIChe2002SpringNationalMeeting,TopicalTH-NuclearEngineeringBrunauer,S.,Emmett,P.H.,andTeller,E.,1938,AdsorptionofGasesinMultimolecularLayers,JournalofAmericanChem.Soc.,Vol.60,pp.309-319.CoxandWilliamson,1977-1979,Hydrogen,ItsTechnology&Implications,Volume1Cleveland,CRCPressEhrensberger,K.,Frei,A.,Kuhn,P.,Oswald,H.R.,andHug,P.,1995,ComparativeExperimentalInvestigationsoftheWaterSplittingReactionwithIronOxideFe1-yOandIronManganeseOxides(Fe1-xMnx)1-yO,SolidStateIonics,Vol.78,pp.151-160.Frostburg,A.,1997-2005,GeneralChemistryOnline:Glossaryaccessed05March.2005.Funk,J.,2001ThermochemicalHydrogenProduction:PastandPresent,InternationalJournalofHydrogenEnergy,Vol.26,No.1,pp.185-190.GoswamiD.Y.,IngleyH.S.,GoelN.,MirabalS.T.,2003,HydrogenProduction,Chapter11,AdvancesinSolarEnergy,Vol.15,D.Y.Goswami,Editor-in-Chief,pp.405-458.Haueter,P.,Moeller,S.,Palumbo,R.,andSteinfeld,A.,1999,TheProductionofZincbyThermalDissociationofZincOxide-SolarChemicalReactorDesign,SolarEnergy,Vol.67,Nos.1-3,pp.161-167.Kameyama,H.,Sato,T.,Amir,R.,Yoshida,K.,Aihara,M.,Sakurai,M.,Tadokoro,Y.,Kajiyama,T.,Yamaguchi,T.,andSakai,N.,1992,CycleSimulationoftheUT-3ThermochemicalHydrogenProductionProcess,InternationalJournalofHydrogenEnergy,Vol.17,No.10,pp.789-794.Kameyama,H.,Tomino,Y.,Sato,T.,Amir,R.,Orihara,A.,Aihara,M.,andYoshida,K.,1989,ProcessSimulationofMASCOTPlantUsingtheUT-3ThermochemicalCycleforHydrogenProduction,InternationalJournalofHydrogenEnergy,Vol.6,No.5,pp.567-575.Kameyama,H.,Yoshida,K.,1978,Br-Ca-FeWater-DecompositionCyclesforHydrogenProduction,Proceedingsofthe2ndWorldHydrogenEnergyConference,pp.829-850.

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119Kameyama,H.andYoshida,K.,1981,ReactorDesignfortheUT-3ThermochemicalHydrogenProductionProcess,InternationalJournalofHydrogenEnergy,Vol.6,No.6,pp.567-575.Kaneko,H.,Hosokawa,Y.,Kojima,N.,Gokon,N.,Hasegawa,N.,Kitamura,M.,andTamaura,Y.,2001,StudiesonMetalOxidesSuitableforEnhancementoftheO2-ReleasingStepinWaterSplittingbytheMnFe2O4-Na2CO3System,Energy,Vol.26,pp.919-929.Kaneko,H.,Ochiai,Y.,Shimizu,K.,Hosokawa,Y.,Gokon,N.,andTamaura,Y.,2002,ThermodynamicstudybasedonthephasediagramoftheNa2O-MnO-Fe2O3systemforH2productioninthreestepwatersplittingwithNa2CO3/MnFe2O4/Fe2O3,SolarEnergy,Vol.72,No.4,pp.377-383.Livage,J.,Henry,M.,andSanchez,Sol-gelChemistryofTransitionMetalOxides,C.,Prog.SolidSt.Chem.,Vol.18,pp.259Meier,A.,Ganz,J.,Steifield,A.,1996,ModelingofaNovelHigh-TemperatureSolarChemicalReactor,ChemicalEngineeringScience,Vol.51,No.11,pp.3181-3186.Morooka,S.,Kim,S.S.,Yan,S.,Kusakabe,K.,andWatanabe,M.,1996,SeparationofHydrogenfromanH2-H2O-HBrSystemwithaSiO2MembraneFormedinMacroporesofan-AluminaSupportTube,InternationalJournalofHydrogenEnergy,Vol.21,No.3,pp.183-188.Nakayama,T.,Yoshioka,H.,Furutani,H.,Kameyama,H.,andYoshida,K.,1984MASCOTABench-scalePlantforProducingHydrogenbytheUT-3ThermochemicalDecompositionCycle,InternationalJournalofHydrogenEnergy,Vol.9,No.3,pp.187-190.Ohya,H.,Nakajima,H.,Togami,N.,Aihara,M.,Negishi,Y.,1994,SeparationofHydrogenfromThermochemicalProcessesusingZirconia-SilicaCompositeMembrane,JournalofMembraneScience,Vol.97,pp.91-98.Ohya,H.,Nakajima,H.,Togami,N.,Ohashi,H.,Aihara,M.,Tanisho,S.,andNegishi,Y.,1997,TestofOne-LoopFlowSchemefortheUT-3ThermochemicalHydrogenProductionProcess,InternationalJournalofHydrogenEnergy,Vol.22,No.5,pp.509-515.Sakurai,M.,Aihara,M.,Miyake,N.,Tsutsumi,A.,andYoshida,K.,1992,TestofOne-LoopFlowSchemefortheUT-3ThermochemicalHydrogenProductionProcess,InternationalJournalofHydrogenEnergy,Vol.17,No.8,pp.587-592.

PAGE 137

120Sakurai,M.,Bilgen,E.,Tsutsumi,A.,andYoshida,K.,1996a,AdiabaticUT-3ThermochemicalProcessforHydrogenProduction,InternationalJournalofHydrogenEnergy,Vol.21,No.10,pp.865-870.Sakurai,M.,Bilgen,E.,Tsutsumi,A.,andYoshida,K.,1996b,SolarUT-3ThermochemicalCycleforHydrogenProduction,SolarEnergy,Vol.57,No.1,pp.51-58.Sakurai,M.,Miyake,N.,Tsutsumi,A.,andYoshida,K.,1996c,AnalysisofaReactionMechanismintheUT-3ThermochemicalHydrogenProductionCycle,InternationalJournalofHydrogenEnergy,Vol.21,No.10,pp.871-875.Sakurai,M.,Nakajima,H.,Amir,R.,Onuki,K.,andShimizu,S.,1999,ExperimentalStudyonSide-ReactionOccurrenceConditionintheIodineSulfurThermochemicalHydrogenProductionProcess,InternationalJournalofHydrogenEnergy,Vol.24,pp.603-612.Sakurai,M.,Nakajima,H.,Onuki,K.,Ikenoya,K.,andShimizu,S.,2000a,PreliminaryProcessAnalysisfortheClosedCycleOperationoftheIodine-SulfurThermochemicalHydrogenProductionProcess,InternationalJournalofHydrogenEnergy,Vol.25,pp.613-619.Sakurai,M.,Nakajima,H.,Onuki,K.,andShimizu,S.,2000b,Investigationof2LiquidPhaseSeparationCharacteristicsontheIodine-SulfurThermochemicalHydrogenProductionProcess,InternationalJournalofHydrogenEnergy,Vol.25,pp.605-611Sakurai,M.,Nakajima,H.,Onuki,K.,Ikenoya,K.,andShimizu,S.,2000a,PreliminaryProcessAnalysisfortheClosedCycleOperationoftheIodine-SulfurThermochemicalHydrogenProductionProcess,InternationalJournalofHydrogenEnergy,Vol.25,pp.613-619.Sakurai,M.,Tsutsumi,A.,andYoshida,K.,1995,ImprovementoftheCa-PelletReactivityinUT-3ThermochemicalHydrogenProductionCycle,InternationalJournalofHydrogenEnergy,Vol.20,No.4,pp.297-301.Sanchez,C.,Livage,J.,Henry,M.,andBabonneau,1988,ChemicalModificationofAlkoxidePrecursors,JournalNon-Cryst.Solids,Vol.100,pg.65.Sasaki,M.,andHirai,T.,1995,CorrosionResistanceofCeramic-coatedStainlessSteelinaBr2-O2-ArAtmosphere,JournalofEuropeanCeramicSociety,Vol.15,pp.329-335.Steinfeld,A.,Sanders,S.,andPalumbo,R.,1999,Designaspectsofsolarthermochemicalengineering-acasestudy:twostepwatersplittingcycleusingtheFe3O4/FeOredoxsystem,SolarEnergy,Vol.65,No.1,pp.43-53.

PAGE 138

121SturzeneggerM.andNuesch,P.,1999,EfficiencyAnalysisforaManganese-Oxide-BasedThermochemicalCycle,Energy,Vol.24,pp.959-970.Tadokoro,Y.,Kajiyama,T.,Yamaguchi,T.,Sakai,N.,Kameyama,H.,andYoshida,K.,1997,TechnicalEvaluationoftheUT-3ThermochemicalHydrogenProductionProcessforanIndustrialScalePlant,InternationalJournalofHydrogenEnergy,Vol.22,No.1,pp.49-56.Teo,E.D.,Brandon,N.P.,Vos,E.,andKramer,G.J.,2005,ACriticalPathwayEnergyEfficiencyAnalysisoftheThermochemicalUT-3Cycle,InternationalJournalofHydrogenEnergy.Vol.30,pp.559-564.Weidenkaff,Steinfeld,A.,A.,Wokaun,A.,Auer,P.O.,EICHLER,B.,andA.,Reller1999,DirectSolarThermalDissociationofZincOxideCondensationandCrystallizationofZincinthePresenceofOxygen,SolarEnergy,Vol.65,No.1,pp.59-69.Weidenkaff,A.,Reller,A.,Sibieude,F.,Wokaun,A.,andSteinfeld,A.,2000,ExperimentalInvestigationsontheCrystallizationofXincbyDirectIrradiationofZincOxideinaSolarFurnace,Chem.Mater.,Vol.12,pp.2175-2181.Westermarck,Sari,2000,UseofMercuryPorosimetryandNitrogenAdsorptioninCharacterizationofthePoreStructureofMannitolandMicrocrystallineCellulosePowders,GranulesandTablets,accessed19April,2005.Yoshida,K.,Kameyama,H.,Aochi,T.,Nobue,M.,Aihara,M.,Amir,R.,Kondo,H.,Sato,T.,Tadokoro,Y.,Yamaguchi,T.,andSakai,N.,1990,ReactorDesignfortheUT-3ThermochemicalHydrogenProductionProcess,InternationalJournalofHydrogenEnergy,Vol.15,No.3,pp.171-178Zheng,H.,Reaney,I.M.,CsetedeGyorgyfalva,G.D.C.,Ubic,R.,Yarwood,J.,Seabra,M.P.,andFerreira,V.M.,2004,RamanSpectroscopyofCaTiO3-basedperovskitesolidsolutions,JournalofMater.Res.,Vol.19,No.2,pp.488-495.

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122BIOGRAPHICALSKETCHBenjaminGrantHettingerwasborninMadison,Wisconsin,in1980.HewasraisedprimarilyinPonteVedraBeach,Florida.HegraduatedfromAllenD.NeaseHighSchoolin1999andthatfallstartedclassesattheUniversityofFlorida.HegraduatedmagnacumlaudewithhisBachelorofScienceinmechanicalengineeringfromtheUniversityofFloridainDecember2003.HethenstartedgraduateschoolattheUniversityofFloridaworkingonhismastersinMechanicalEngineeringintheareaofthermalscience.AftergraduatingheplansonworkingatCDIAerospaceinWestPalmBeach.HispurposeinlifeistoglorifyJesusChristhisLordandSavior.


Permanent Link: http://ufdc.ufl.edu/UFE0010960/00001

Material Information

Title: Development of Calcium Oxide Solid Reactants for the UT-3 Thermochemical Cycle to Produce Hydrogen from Water
Physical Description: Mixed Material
Copyright Date: 2008

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Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
System ID: UFE0010960:00001

Permanent Link: http://ufdc.ufl.edu/UFE0010960/00001

Material Information

Title: Development of Calcium Oxide Solid Reactants for the UT-3 Thermochemical Cycle to Produce Hydrogen from Water
Physical Description: Mixed Material
Copyright Date: 2008

Record Information

Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
System ID: UFE0010960:00001


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DEVELOPMENT OF CALCIUM OXIDE SOLID REACTANT FOR THE UT-3
THERMOCHEMICAL CYCLE TO PRODUCE HYDROGEN FROM WATER

















By

BENJAMIN GRANT HETTINGER


A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE

UNIVERSITY OF FLORIDA


2005

































Copyright 2005

by

Benjamin Grant Hettinger














ACKNOWLEDGMENTS

Many people have assisted me in the past year and a half with this thesis project

here at the University of Florida. I could not have completed this task without the help

these people who gave me their time, taught me knowledge, challenged me to think

critically, and supported me throughout the project.

I thank Dr. D. Yogi Goswami for the opportunity to investigate this challenging

research project and his encouragement to investigate all aspects of the project. I thank

my committee members, S. A. Sherif, Dr. H. Ingley, and Dr. H. Hagelin-Weaver, for

their advice and support throughout the project.

I thank Dr. Deshpande for his tireless efforts to aid me in understanding the

subject of my research, for continuing to push me to stay diligent, for helping me write

and edit my thesis, and for being a helpful advisor. He has been there at every step of

this project and helped to impart academic knowledge in many aspects of research. He

has especially helped me to more quickly grasp the chemical engineering and chemistry

which encompass the majority of this project.

I thank Chuck G. for teaching me how to use many of the tools at the shop and

also for imparting on me practical engineering knowledge and critical thinking. I also am

grateful for the members of the lab group that advised me on solutions to problems in

research, challenged me to investigate problems further, and who helped me to find and

to use items in the lab.









I had a lot of help at the different facilities and with the variety of equipment I

used. I thank Dr. Anghai and Tom Carter and those at the nuclear laboratory for the use

of their facilities and friendly and helpful assistance. I also thank Dr. Hahn for the use of

the his aid in understanding Raman spectroscopy and X- Ray diffraction. I thank Gary

Scheiffele for his training on Raman spectroscopy and mercury porosimetry and his

willingness to help me understand their use and limitations. I thank Gill Brubaker for his

training on the NOVA machine for nitrogen adsorption analysis. I would also like to

thank other people at the Particle Science Engineering building who helped to orient me

with use of their equipment. I acknowledge financial support from the US Department of

Energy which allowed me to investigate this project. Without these people I could not

have finished my project.

I thank my parents, Jean and Glenn Hettinger, and the rest of my family in their

constant support of my education. I thank my friends and Kappa Sigma fraternity

brothers for their support and help over the years. Most of all I thank my Lord Jesus

Christ who has sustained me through life thus far especially during the tough times.















TABLE OF CONTENTS

page

A C K N O W L E D G M E N T S ......... ............................ .. ..................................................iii

LIST OF TA BLES ..................................... ......... .... ............. ix

LIST OF FIGURES ...................................... ....... .... .............. x

LIST OF SYM BOLS ............................................. .... ............. xiii

A B S T R A C T ................................ ..................................................... x v i

CHAPTER

1 IN T R O D U C T IO N ........ ................................................................... ................ .. 1

Current Hydrogen Production M ethods......................................................... ..... 1
F o ssil F u e ls ............................................... ........................... 2
Steam m ethane reform ation ........................................ ................ .............. 2
Partial oxidation m ethod ............................. ............................... .............. 3
Coal and biom ass gasification ........................... ....... ........................ 3
E lectro ly sis ................................................. ................ .................... 4
Thermal Decomposition of W ater ................................. ....................... 5
Therm ochem ical Processes ................... .. ............... .......... .... 6
Photoelectrical and Photochemical Hydrogen Production .................................... 6
Biological Hydrogen Production ........................... ....... ........................ 7
T herm ochem ical C ycles ........................................ .. ........................... .............. 7
Ispra Mark Processes ............. .............................. 7
Sulfur-Iodine or M ark 16 or GA Process ............. .............. ............. ............ 9
M etal O x ides .............................................................................. .............. 10
M miscellaneous Processes ........ ....... .... ................. ...... .............. 12

2 THE UT-3 THERMOCHEMICAL PROCESS ............................................. .. 13

History of Research on the UT-3 Thermochemical Process................................. 14
Process and Sim ulation Studies .................................. ................. 15
Membrane, Separation Techniques, and Materials........................................ 22
Solid R eactants............................................ ....... ......... ...... 24
Iron reactants............................................ ...... .......... ..... 24
Calcium reactants ............... .. .... ...... ............... .... .. ........ ............ .. 27









Strengths and Weaknesses of the UT-3 Thermochemical Process..................... 33
C alcium O xide Solid R eactant........................................................ .... .. .............. 34
P h y sical C h aracteristics ........................................................................................ 3 5
P o ro sity .................................................................................................... 3 5
Strength ......................................................................................................... 35
C hem ical C characteristics ............................................... ........................... 36
C hem ical com position ............................................... ........................... 36
R activity ............................................................... ... .... ........ 36
Degradation .................................................... 37
R research O objective ............................................... ........ ............ .. 37
C hem istry Form ulation ....................................................................... 38
Physical Formation ... ... .............................................. .............. 39

3 SOLID REACTANT .. ............................................................ .............. 40

Sol-Gel Chemistry ........................................... .... .......... .. 40
H y droly sis ............................................ 4 1
C ondensation ......................................... 42
C h em ical F orm u lation .......................................................................................... 44
Q ualitative investigation .............. ............................................ .............. 44
Original procedure .............. ............................................ .............. 45
M odified procedure ........................................... .. ....... .. .......... .. 48
M ixing ratios .................................... .......................... .... ........ 52
Physical Procedures ..................................... .................. .. 52
D trying ..................................... .................................. ......... 52
M olding.................................... .................. 53
H hydraulic press .................... ................. ............................... 53
O original m old ................ ................ .................. ........ ..... ........... 54
Modifications in mold and molding procedure.............................................. 57
S in te rin g ...................................................................... .............. 5 8

4 AN A LY TICA L TO O LS ........................................................................ 61

N nitrogen A dsorption .... ............................................... ....... ..... .............. 61
B E T Iso th erm ...................................... ...................................................................... 6 2
B JH P ore Size D distribution .......................................................................... ... ... 63
Mercury Porosimetry ............................................. ............ .. 65
T h e o ry ...................................................................................................... 6 5
P procedure ........................................ 66
Ram an Spectroscopy ................................................. ...... .... ............ .. 66
T h e o ry ...................................................................................................... 6 6
P procedure ........................................ 67
C h em ical T estin g ....................................................................... 6 8
T h e o ry ...................................................................................................... 6 8
P ro cedu re .. .. .......................................... .......... .. .. ....... ............ 6 8









5 EVALUATION OF PARAMETERS ............................................ ................... 69

Correlations from Original Chem istry ............................ .................................. 69
M holding Procedure: Strength ............................ ................ ............................ 70
Heating Procedure: Strength and Microporosity ............................................... 70
Chemistry: Chemical Composition......................... ......................... 72
Correlations from Modified Chemistry ...................................... ............... 73
Molding Procedure: Strength and Macroporosity............... ....... .......... 73
Chemistry: Macroporosity, Microporosity, Composition, and Strength ........... 74
Heating Procedures: Composition, Strength, and Porosity............................ 79
Optimum Parameters .. ................. .......................... .. .......... .. 80

6 RECOMMENDATIONS FOR FUTURE WORK ............................................ 84

S h ort T erm P lan .................. ............................................................ ................ .. 8 5
Investigation into R activity ...................................... ................ .................. .. 85
R action rates ............................................................... .. ... ........... 85
C conversion .........................................................................6
Investigation of Degradation...................................................... 86
Investigation of Cyclic Strength ........................................ ................. ...... 87
Creative Engineering .. ..................................................... ....... .............. 87
L ong T erm Plan ..................... ........................ ........... ......... ...... 87
M ass P reduction of P ellets............................................................................. ... 87
Pellet Performance in a Fixed Bed Reactor ..................................................... 88

7 SUMMARY AND CONCLUSIONS ....................................................... 89

APPENDIX

A CH EM ICAL PROPERTIES .............. ............................................................ 91

B RAM AN SPECTROM ETER .......................... ................................ .............. 92

C PELLET MAKING PROCEDURES ................................................. ............. 94

O rig in al C h em istry ............................................ .. ................. ........ ................... 9 4
M modified Chemistry .................. .......... ............ ................ ....... 94
Drying and Preheating .. ... ................................................... .............. 96
M holding ..................................... ......... .......... 96
H eating Procedures ................................ ....... .. ...... .. .... .. .......... .. 97









D PELLET CHARACTERIZATION PROCEDURES ...................... .............. 98

N itro g en A d so rp tio n ................................................................................................. 9 8
O utgassing Procedure .................................................... ........................... 98
Full Isotherm A analysis Procedure.............................................. .... .. .............. 99
Quantachrome Mercury Porosimeter.................................................... 102
Filling Apparatus Procedure .................................. 102
High Pressure Procedure ........... .. ......... ....... .............. 104

E R A M A N SP E C T R A ................................................................. .................... 107

F MERCURY POROSIMETRY DISTRIBUTIONS ............ ...... ............ .. 113

L IST O F R E FE R E N C E S ...................................................................... ..................... 117

BIOGRAPHICAL SKETCH ............................................................. ............... 122















LIST OF TABLES


Table page

1.1 Reduction Temperatures for Researched Metal Oxides .......................................... 11

2.1 Comparison of Initial Rates of the UT-3 Thermochemical Process ...................... 25

2.2 Properties of Calcined Iron Solid Reactant Pellets ............. ............ ............. 27

3.1 Qualitative Reaction Study ..................................................................... 45

3.2 Original Mixing Ratios for Modified Chemical Formulation Procedure ................. 49

5.1 Parameters in the Main Categories Shown in Figure 5.1........................................ 70

5.2 Results of Quantatative Chemical Composition Testing Procedures ......................... 77

5.3 Optimum Parameters ............................................... 81

A.1 Chemical Properties of Various Solid and Liquids Used in this Project ................. 91

C.1 Chemical Ratios Used in Modified Chemistry ................................ .............. 95
















LIST OF FIGURES


Figure

1.1 Two-step Water-Splitting Oxides Reduction Processes ......................................... 11

2.1 Flow Sheet of the Solar UT-3 Thermochemical Process.......................................... 13

2.2 Conceptual Illustration of W hole Plant............................................................... 16

2.3 Illustrative Diagram of the MASCOT Plant ................................................ 17

2.4 Time Histories of the Rate of Hydrogen Production ............... .................. 17

2.5 Original (a) and New (b) Flow Sheets of the UT-3 Process .............................. 18

2.6 Energy Balance of the UT-3 Hydrogen Plant............. ............................................ 19

2.7 History of Total Gas Production by Cyclic Operation................................ 20

2.8 Thermal Efficiency of UT-3 Hydrogen Plant Having Membrane Separation ........... 21

2.9 Process for Pelletizing Solid Reactants ....................................... ........ ............. 25

2.10 Relationship Between Pore Volume and Additive Graphite Content in Pellet ........ 26

2.11 Production Process of the Pellet Using Ca and Ti Alkoxide ............................... 28

2.12 Solid Conversion Profiles of Bromination and Hydrolysis by Cyclic Operation..... 29

2.13 Pore Size Distribution of Unreacted(u) and Brominated (b) Pellets Made from the
Old M ethod and the New Alkoxide M ethod.................................. .................... 29

2.14 Flow Chart of a Modified Method for the Preparation of a Pellets Using Alkoxide
M ethod w ith a D ispersion C hain ........................................ .................. ...... 30

2.15 Comparison of the Solid Conversion Profiles of Bromination and Hydrolysis
Between the Conventional Method (Alkoxide) and Modified Method ................. 31

2.16 Comparison Between Computed and Observed Time Histories of Bromination..... 32









2.17 Change of Pore Volume in Cyclic Operation .................................. .............. 32

2.18 Change of Pore Volume During Bromination. ...................................................... 33

3.1 Production Process of the Pellet Using Ca and Ti Alkoxide ................................... 45

3.2 Three M outhed Flask on Stirring Heater .......................................... ..... ......... 48

3.3 Flow Diagram of Procedure Outlined by Aihara et al. .......................................... 50

3.4 Hand Pumped Uni-axial Hydraulic Press for Pellet Production ............................. 54

3.5 Pellet M old A ssem bly ............................................. .. .......... .......... 54

3.6 P ellet M holding A ssem bly Parts............................................................................. ... 55

3.7 Furnace U sed for Sintering Process ........................................ ................... ..... 60

3.8 H eating Schem es for P ellets ...................................................................................... 60

4.1 Typical BET Isotherm .............................................................. .......................... 63

4.2 Schematic Representation of Assumed Desorption Mechanism Showing Three
Different Pores and Demonstating the Thinning of the Physically Adsorbed Layer
Over the First Three Decrements .......................... ......... ............ ....... 64

5.1 Flow Diagram Indicating How Characteristics were Used as Feedback to Modify the
Parameters to Arrive at the Final Procedures ................................ .............. 70

5.2 Specific Cumulative Micropore Volume vs. Maximum Sintering Temperature........ 71

5.3 Raman Shift Spectra of Anatase and Rutile TiO2 and Two Representative Pellets
M ade U sing the Original Chem istry .................................. ................................... 72

5.4 Visual Flow Diagram of How Characteristics were Used as Feedback to Modify the
Parameters Using the M odified Chemistry............... ............................................ 73

5.5 Comparison of Cumulative and Differential Specific Pore Volume Distribution for
New Pellets Compressed at 0.25 and 0.5 Metric Tons. ........................................ 74

5.6 Raman Shift Spectra for CaTiO3 and Two Sample Pellets.............. ... ............. 76

5.7 X-ray Diffraction Data with Peaks Verifying the Presence of Both Calcium Oxide
and Calcium Titanate ... ... ................................................ .............. 78









5.8 Comparison of Micropore and Macropore Volume of Pellets Made with Ratios of
Different Calcium to Titanium Ratios with UT-3 Porosity Results ................... 79

5.9 Comparison of Cumulative and Differential Specific Pore Volume Distribution for
New Pellets Sintered at Different Temperatures.. ......................... .............. 81

B 1 R am an M odule ......... .......................... ... .......... ........ .......... 92

B .1 Inside of FT R am an M odule .............................................. ............................ 93

D.1 Quantachrome NOVA 1200 Machine for Nitrogen Adsorption with Small Sample
Cell and Dewar ..... ........... ........................... 101

D.3 Quantachrome Mercury Porosimeter Filling Apparatus............... ................. 105

D.2 Quantachrome M ercury Porosimeter ................................................ ... .............. 105

E. 1 Raman Spectra Showing the Pellets Made with Original Chemistry are Mostly
Composed of Anatase and Rutile TiO2........................................... ................ 108

E.2 Raman Spectra Showing the Fluorescence Hiding the Characteristic Peaks of a
Sample Made Using the Modified Chemistry ............................................... 109

E.3 Raman Spectra Showing the Existence of CaTiO3 in the Two Pellet Samples Via the
M watching Peaks to a Standard ....................................................................... ...... 110

E.4 Full Raman Spectra Showing the Existence of CaTiO3 in the Two Pellet Samples Via
the M watching Peaks to a Standard............................................... ............... ... 111

E.5 Full Raman Spectra Showing the Existence of CaTiO3 in the Two Pellet Samples Via
the Matching Peaks to a Standard Taken with the Same Laser Intensity on the Same
S c ale ............................................................................................ 1 12

F.1 Comparison of Cumulative and Differential Specific Pore Volume Distribution for
New Pellets Made with Different Ca to Ti Ratios .............................................. 114

F.2 Comparison of Cumulative and Differential Specific Pore Volume Distribution for
New Pellets Compressed at 0.25 and 0.5 Metric Tons. ........................................ 115

F.3 Comparison of Cumulative and Differential Specific Pore Volume Distribution for
New Pellets Sintered at Different Temperature ......................................... ..... 116














LIST OF SYMBOLS


Chemical Elements

Br Bromine

Ca Calcium

C Carbon

Cl Chlorine

Fe Iron

H Hydrogen

I Iodine

Mn Manganese

Na Sodium

0 Oxygen

S Sulfur

Si Silicon

Ti Titanium

Zn Zinc

Zr Zirconium

Calcium Compounds

CaBr2 Calcium Bromide

CaCO3 Calcium Carbonate

Ca(OH)2 Calcium Hydroxide









CaO Calcium Oxide

CaTiO3 Calcium Titanate

Other Chemistry Symbols

+6 Positive partial charge

-8 Negative partial charge

e- Electron

M Metal Atom

m Stoichiometric symbol

n Stoichiometric symbol

R Organic molecule

x Stoichiometric symbol

y Stoichiometric symbol

Other Symbols

y Mercury surface tension [degrees]

0 Mercury contact angle [dyne/cm]

Cv Concentration of vacant sites on reaction surface [mol/L]

CN2-s Concentration of sites with nitrogen adsorbed [mol/L]

Csubscript Concentration [mol/L]

HH2 Power of hydrogen produced based on HHV [MW]

HHe Heat input from helium [MW]

HR Heat recovered [MW]

HX Heat exchanger

Int Relative intensity of light [counts]









kA Adsorption rate coefficient [1/(psia*s)]

KA Equilibrium adsorption constant [1/psia]

MT Metric tons

P Pressure [psia]

Pc Power consumed [MW]

Po Ambient pressure [psia]

PN2 Pressure of nitrogen [psia]

r3s Rate of reaction 3 [mol/(L*s)]

rAD Rate of adsorption [mol/(L*s)]

R Universal gas constant [J/(gmol*K)]

R1-R4 Reactors 1 through 4 respectively

S1-S2 Separators 1 and 2

T Temperature[K or C]

X Conversion















Abstract of Thesis Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Science

DEVELOPMENT OF CALCIUM OXIDE SOLID REACTANT FOR THE UT-3
THERMOCHEMICAL CYCLE TO PRODUCE HYDROGEN FROM WATER

By

Benjamin Grant Hettinger

December 2005

Chair: D. Yogi Goswami
Major Department: Mechanical and Aerospace Engineering

Hydrogen may be the answer to meeting the world's energy demand as it

increases and the fossil fuel sources run out. The University of Tokyo #3 (UT-3)

thermochemical cycle is being researched as a means of producing hydrogen from water.

In order to make the UT-3 thermochemical cycle economically feasible, the operating

temperatures for the reactions must be reduced. In order to study this cycle, the solid

reactant must be in a form that will allow the reactions to take place efficiently. A

procedure to make the solid reactant for the UT-3 thermochemical cycle has been

developed using outlines from previous researchers. The procedure includes chemical

procedures to make the precursors, drying and preheating, molding, and sintering

procedures.

Sol-gel chemistry was used to create the particulate precursors for the pellets.

The liquor resultant from the chemistry procedure was dried via evaporation and then

preheated to 4300C to eliminate volatiles. The resultant powder was molded into pellets









using a compression mold which had been fabricated. The pellets were then sintered to

temperatures above the highest operation temperature of the UT-3 cycle, 760C in order

to strengthen the pellets.

The characteristics of the fabricated pellets were used to gauge the success of the

process and modify it as necessary to yield better characteristics. The characteristics of

the pellets which were used to evaluate the procedure were the porosity, the composition,

and the strength. The porosity was evaluated by mercury porosimetry and nitrogen

adsorption. The composition was determined qualitatively by Raman spectroscopy and

X-ray diffraction and quantitatively by a chemical procedure. The strength was evaluated

qualitatively.

Based on these characteristics a number of changes were made to the procedure

including a new chemical procedure, a redesigned molding assembly, and the addition of

a preheating step. Correlations were also made between certain characteristics and

procedural parameters. One correlation showed that there was an increase in strength

with sintering temperature but a decrease in both macro and micro porosity. Another

correlation showed that the strength of the pellets decreased with an increase in the ratio

of calcium to titanium used in the pellets.

Though these pellets seem to have acceptable characteristics, more characteristics

including reactivity and degradation need to be studied. These pellets may not hold up

structurally or may not react as well as they must. Further study needs to be done to truly

determine the success of this process. More importantly, the pellets are just the first step

toward studying the UT-3 thermochemical cycle.


xvii














CHAPTER 1
INTRODUCTION

The world energy consumption is rising as more and more countries become

industrialized. Currently the most abundantly used sources of energy are fossil fuels.

These, however, are limited and most projections show that the production of oil will not

meet the need within the next 10 to 25 years. This presents a major problem to energy

consumers around the world but especially for transportation where oil is almost the sole

energy source. Looking ahead the United States is seeking the solution in hydrogen

powered transportation. The U.S. government along with automobile manufacturers is

pushing researchers to investigate hydrogen to meet this upcoming need. Hydrogen has

been shown to be 40 to 50% efficient in fuel cells and is environmentally friendly

producing steam as its only by-product. There are many problems that must be solved in

order to make the "hydrogen economy" feasible. A large amount of research is being

conducted to investigate hydrogen production, fuel cells, storage, safety, and

infrastructure.

This research focuses on a small but important aspect of one of the potential

hydrogen production processes. In this chapter an overview of the present methods for

hydrogen production is presented and discussed.

Current Hydrogen Production Methods

There are a number of methods that can be used to produce hydrogen. These

methods include steam methane reformation (SMR), partial oxidation of fuels (POX)









coal and biomass gasification, electrolysis, thermal decomposition, thermochemical

processes, biological, and other processes. Some of these have been found to be

impractical, such as, thermal decomposition. Others are established means of hydrogen

production and still others are currently being investigated and may be viable options in

the future. Ideally a process is sought that is a cost effective and energy efficient means

to produce hydrogen using a renewable energy source. This would allow utilization of all

the benefits of hydrogen as a fuel.

Fossil Fuels

The most cost effective way to produce hydrogen is to use one of the fossil fuel

processes. Though these processes are efficient and cost effective, they also eliminate on

of the major advantages of hydrogen. The green house gas CO2 is still being produced if

hydrogen is produced in this manner. Though, biomass is not considered a fossil fuel it

has been included with coal gasification because of the similarity in the processes. It is

considered a carbon neutral means of hydrogen production. Also the reason hydrogen is

being researched as a fuel source is because of the depleting fossil fuel sources.

Steam methane reformation

Steam methane reformation (SMR) has many benefits and is the most economical

method of producing hydrogen now. It is a process in which steam and methane are

combined at high temperatures (7000C to 9250C) using a catalyst. A sulfur separation

step is needed so that the catalyst will not be destroyed. After the first reaction an

equilibrium shift reaction is added to produce more oxygen in the cycle. The total

process result is 96-98% pure hydrogen with an efficiency of 65-75% (Goswami et al.,

2003). The heat is supplied by burning fossil fuels. There are two drawbacks to this

method. First the method is not "clean" or "green". It produces the green house gas, CO-









2. Second it relies on the limited amount of methane on the earth. As the supply dwindles

the feedstock cost will rise and make SMR less economical than other processes. The

chemical scheme for SMR can be seen below in Equations 1.1 and 1.2 (Cox and

Williamson, 1977-1979).

H n( 2-n + mr.2
C -H +n-H- O= n-CO+ + -H
2 n'H2O=knCO + 2)2 (1.1)
n m 2 2

CO+ O = CO2 + (1.2)

Partial oxidation method

The next most popular method of hydrogen production is partial oxidation of

heavy hydrocarbons (POX). This method is very similar to SMR with the addition of a

step. In this additional step heavy hydrocarbons are partially burned with pure oxygen

and water. Simultaneously, the heavy hydrocarbons are broken down into less complex

hydrocarbons such as methane which is reacted with steam in a similar manner as in

SMR. The resulting products are CO, CO2, H20, H2. After a desulphurization step the

shift reaction is again used to produce more hydrogen. POX produces hydrogen with a

purity of 96-98% and an efficiency of about 50% (Goswami et al., 2003). The same

problems exist with POX as did with SMR. The additional step of oxygen separation

increases the cost of this process compared to SMR.

n m
nm 2 22 (1.3)

(2.n + m)I
C-H + n-O + Heat = nCO + -2 H 2 (
n m 2 2 (1.4)

CO + H2O = CO2 + H2 + Heat (1.5)

Coal and biomass gasification

Coal and biomass gasification are very similar to POX with the differences of a

higher temperature range (11000C -13000C), higher pressures, and there is very little









oxygen present. The high carbon content of coal and biomass is converted to CO2, H2,

and CO. After a desulphurization step the shift reaction is again used to produce more

H2. Purity of hydrogen of up to 97% has been obtained using coal gasification (Goswami

et al., 2003). Coal is the most abundant fuel on earth and supplies will probably not be a

concern for a century from now. Like those mentioned before, this process produces the

greenhouse gas, CO2.

Using biomass as the fuel other benefits and problems exist. Benefits include

valuable byproducts such as ammonia, better pollution control, and lower operating costs.

Biomass is also considered a carbon neutral fuel because the CO2 would be produced

through natural decomposition anyway. The problems lie in transporting the solid fuel

and disposing of the large quantities waste ash that are produced.

2C+0242CO (1.6)
C+H20 CO+H2 (1.7)
C+C0242CO (1.8)
All these processes based on fossil fuels produce CO2. Presently they are the

most cost effective ways to produce hydrogen. The main benefit of hydrogen as a fuel is

that it does not produce any harmful by products when used to make energy. If it is

produced in a manner in which CO2 is created this benefit is essentially eliminated.

Alternative methods must be used if this benefit is wanted.

Electrolysis

Electrolysis of water is the next most commonly used means to produce

hydrogen. In electrolysis a voltage is supplied so that electricity flows through a medium

and ions are conducted across a membrane. H2 is produced by combing H+ ions and two

electrons at the cathode as shown in Equation 1.9. Water is split at the anode so that 02









is produced along with H ions and electrons as seen in Equation 1.10 (Cox and

Williamson, 1977-1979)

H20-.5 02 +2H+2e- Anode (1.9)
2H++2e-"H2 Cathode (1.10)


Electrolysis has been researched extensively and some ideas presently being

considered are the electrolysis of sea water and efficiency increase with temperature

variance. Electrolysis has been seen to be 94% efficient based on the electrical power

input to the system (Goswami et al., 2003). This electricity however comes from another

source. Solar produced electricity is a very good source to use for electrolysis. Almost

all the electricity produced by solar means can be used to make hydrogen. This creates a

clean way to produce hydrogen and can eliminate any fossil fuels from the process.

Thermal Decomposition of Water

When water is heated to very high temperatures some of the steam decomposes to

02, H2, OH, O, and H. At first glance this process seems very simple, but it has many

problems. A large amount of energy has to be supplied to heat water to the needed

temperatures. The steam does not even fully dissociate until a temperature above 4000K

is reached. The mixture of dissociated gases is also highly explosive which creates a very

serious danger. Finding containers that can withstand the temperatures needed for the

operation also presents a problem. High temperature gas separation is also hard to do.

Quenching can be done but the heat lost during the process can not be recovered and

makes the process too costly to operate. Only 2.1% efficiency has been recorded using

the thermal decomposition of water to produce hydrogen and only a 40% theoretical









efficiently has been calculated (Goswami et al., 2003). Obviously, this process is not

feasible unless solutions are found to these problems.

Thermochemical Processes

In thermochemical processes water is input along with heat and oxygen and

hydrogen are produced. The overall result then is the same as that of thermal

decomposition. These processes are much different, however, and much more practical.

The processes have been theoretically modeled to be up to 50% efficient dwarfing the

2.1% efficiency of the thermal decomposition of water (Sakurai et al. 1996). Much lower

temperatures can also be used and hydrogen and oxygen can be produced in different

steps eliminating an explosive mixture of gases. Each thermochemical process however

has its own problems that must be considered to make the process feasible.

Inside this black box system a series of heat driven chemical reactions are used to

produce hydrogen and oxygen. There are thousands of proposed processes but only a

few which have been studied extensively and even fewer that hold promise in large scale

implementation. Some of these processes are discussed later in this chapter.

Photoelectrical and Photochemical Hydrogen Production

Photoelectrical systems couple a solar voltaic cell with electrolysis. A photo

anode absorbs sunlight creating a current to flow and electrolysis to occur. Hybrids of

this system have reported efficiencies of up to 18% (Goswami et al., 2003). In

photochemical systems semiconductors are paired with photosensitive organic particles.

When light hits the photosensitive particles electrons are excited and are directly used to

carry out the reduction and oxidation reactions to create hydrogen. There are problems in

the catalyst and photosensitive material degrading, back reactions, and the separation of

hydrogen and oxygen. Photochemical systems have yet to reach 10% efficiency









(Goswami et al., 2003). More investigation must be conducted to evaluate the feasibility

of these hydrogen production methods.

Biological Hydrogen Production

There are two general biological methods that are used to produce hydrogen. The

first is the fermentation of bacteria. In this process organic substances are converted to

oxygen and hydrogen without sunlight or oxygen. The theoretical efficiency for this

process is only 33% (Goswami et al., 2003). Treatment of the polluted process water

may also be a problem which should be addressed when considering this process.

The second method is called biophotolysis. In this process micro-algae-

cynobacteria and green algae are exposed to sunlight and water. Through organic

processes they produce hydrogen and oxygen. There are two types of bacteria,

nitrogenase and hydrogenase. The first of the two uses ATP molecules and coverts them

to ADP molecules releasing H+ ions in the process which form hydrogen. Hydrogenase

produces hydrogen by breaking down carbohydrates in a photosynthesis system. Both

will die in the presence of a small amount of oxygen (Goswami et al., 2003).

Thermochemical Cycles

There are thousands of thermochemical processes. The processes vary widely in

many different aspects though some are very similar. Many of the processes are slight

modifications of a previous cycle, including a substitute reaction or reactions and/or an

imposed voltage. Processes with imposed voltages are known as hybrid thermochemical

cycles.

Ispra Mark Processes

The first thoroughly researched process is the Ispra Mark I process shown below.

As can be seen mercury is used in this process. Mercury is known to be a very toxic









element and research on this process was discontinued because on a larger scale use the

process would be too much of a safety risk for consideration. The process was important,

however, as it was a harbinger of the exploration of thermochemical cycles. It was the

first process demonstrated to give reasonable amount of hydrogen at an acceptable

efficiency. Other processes followed the Ispra Mark I and there are now 17 Ispra Mark

processes some of which have different sub-processes. The series of Ispra Mark

processes are some of the most promising thermochemical processes.

Ispra Mark I

CaBr2+2H20-Ca(OH)2+2HBr (7300C) (1.12)
2HBr+Hg4HgBr2+H2 (2500C) (1.13)
HgBr2+Ca(OH)2- CaBr2+HgO+H20 (2000C) (1.14)
HgO -Hg+.502 (6000C) (1.15)


Much work has been done in exploring the possibility of using iron-chloride in

processes. Ispra Mark processes 7, 7A, 7B, 9, 14, and 15 contain iron-chloride. Problems

in these processes have been found and generally stem from either the thermal

decomposition of FeCl3 (Eq. 1.17) or the hydrolysis of FeCl2 (Eq. 1.18). Much research

has been conducted to eliminate these problems but no viable solution has been found.

The iron-chloride family of reactions was deemed uneconomical and research has been

focused elsewhere. Ispra Mark 7B can be seen below.

Ispra Mark 7B

2Fe2O3+6Cl2-4FeCl3+302 (10000C) (1.16)
2FeCl3- 2FeCl2 +C12 (4200C) (1.17)
3 FeCl2 + 4H20- Fe304 + 6 HCl+ H2 (650C) (1.18)
Fe304 + 02 6Fe203 (3500C) (1.19)









Another focus area of research was the sulfur family processes, mostly concerning

the decomposition of sulfuric acid. The Ispra Mark 4, 10,11,12,13, 16 and 17 processes

all use sulfur, but the ones that focus on the decomposition of sulfuric acid are 11, 13, 16,

and 17. Each process starts with the thermal decomposition of sulfuric acid but there are

4 different schemes to finish the respective processes, three of which are shown below.

Decomposition of Sulfuric Acid
H2S04-2S02+2H20+02 (1.20)


Ispra Mark 11 (also known as Westinghouse)
SO2+ 2H20 +elec H2SO4+ H2 (1.21)


Ispra Mark 13
2H20+Br2+SO2-H2SO4 + 2HBr (1.22)
2HBr+elec Br2 + H2 (1.23)


Ispra Mark 16 (also known as the General Atomic Process and the sulfur-iodine process)
2H20+ I2+S02-H2S04+2HI (1.24)
2HI-I2+H2 (1.25)


The Ispra Mark 16 process is also known as the General Atomic (GA) process

because of GA's extensive work on it. It shows much potential and is one of the most

researched processes.

Sulfur-Iodine or Mark 16 or GA Process

12+SO2+H20-2HI+H2S04 (100 C) (1.26)
2HI-H2+12 (4200 C) (1.27)
H2S04-H20+SO2+ .502 (850 C) (1.28)


The GA process has many desirable aspects. Three reactions are used at

relatively low thermochemical process temperatures. The reactions can also be arranged









to create a continuous process. Many people have studied this reaction and it has been

well researched. Theoretical efficiencies have been predicted to be approximately 50%.

There are expensive separation and purification steps that needed to be considered. This

process also uses highly acidic chemicals. In addition there have been problems with

hydriodic acid decomposition. At 700K there is only a 25% dissociation which cannot be

greatly increased with temperature. This, therefore, makes it necessary for the products

to be recirculated creating thermal losses. Another factor that must be considered is the

possibility of side reactions which can form sulfur and hydrogen sulfide. Despite these

problems, this process is being studied at a number of places and has arguably the most

potential of thermochemical processes to be used to produce hydrogen (Sakurai et al.,

1999, 2000)

Metal Oxides

MxO = xM + y/2 02 (High Temperature reduction reaction) (1.29)
xM + yH20 = MxOy + yH2 (Low Temperatures oxidation reaction) (1.30)


Another large area of research within thermochemical processes is being

conducted on metal oxide reduction-oxidation redoxx) processes. Metals are reduced

with heat creating a pure metal and releasing oxygen. The metal is oxidized with water

to form a metal oxide once again. The metal steals the oxygen from the water so that

hydrogen is released. There are a number of metals and alloys being considered at this

time. The simplicity of the processes seems appealing, having only 2 reactions. Most of

the oxidizing reactions proceed without problem. An undesirable requirement of these

processes is that the reduction reaction occurs at very high temperatures. Much of the









work being done is to find an alloy that will significantly lower the temperature of the

reduction reaction.

One of the most promising is the zinc oxide reaction. Reported conversion

efficiencies have been as high as 50% (Weidenkaff et al., 2000). The temperature for the

reduction reaction however is 2300K. The process is depicted below in Figure 1.



Concentrated
Solar Radiation
/ ZnO H2



Solar Reactor Water Splitting Reactor
1st Step @ 2300K 2nd Step @ 700K
ZnO --> Zn(g) + 02 Zn+H20-->ZnO+H2


2 02 n H2
0- ZnO -

Figure 1.1 Two-Step Water-Splitting Oxides Reduction Processes
(Weidenkaff et al., 1999)

Other metals and alloys considered are listed below with their reduction

temperature. Some of the temperatures have been reported over a range of temperatures.

For simplicity, one value was chosen and the actually temperatures will vary somewhat

based on the experimental design. The Table is just to show typical temperature values

for thermochemical metal oxide processes.

Table 1.1: Reduction Temperatures for Researched Metal Oxides
Metal or Alloy [K] [C] References
ZnO 2000 1727 Weidenkaff et al., 2000 & Hauter et al., 1999
Mn203 1835 1562 Meier et al., 1996 & Sturzenegger and Nuesh, 1998
Fe304 2300 2027 Steinfeld et al., 1999
MnFe204 1273 1000 Ehrensberger et al., 1995
Na3(MnFe2)06 1073 800 Kaneko et al., 2001,2002









Miscellaneous Processes

There are other processes that have been researched by different groups. Most

groups are found either at universities or scientific labs around the world.

One group at the University of Tokyo developed one of the most promising

processes. They have done extensive research on the process and up-scaled their

laboratory scale model. It is predicted to be the first thermochemical process that will

actually be used for large scale hydrogen production. This process is know as the UT-3

process and will be discussed in more detail in the next chapter.

Another process that might have potential is the Julich Center EOS shown below.

2Fe304+6FeSO4- 6Fe203+6SO2+O2 (8000C) (1.31)
3FeO+H20-Fe304+H2 (7000C) (1.32)
Fe203+SO2-FeO+FeSO4 (2000C) (1.33)


It is in the beginning stages of research and has many desirable attributes. Reactants in

this cycle are not corrosive. Besides oxygen and hydrogen, the only elements used are

sulfur and iron which are very abundant on the earth. Early testing shows the reactions

go as written. Not much current research is being conducted on this process, however.

This may be due to other significant problems encountered (Brown et al., 2002).

















CHAPTER 2
THE UT-3 THERMOCHEMICAL PROCESS

The University of Tokyo #3 thermochemical (UT-3) process was proposed in

1978 by Kameyama and Yoshida at the 2nd World Energy Conference (Kameyama and

Yoshida, 1978). A UT-3 cycle is composed of a series of four thermochemical reactions

which are shown below. The operating temperatures are relatively lower than those

found in other thermochemical cycles, the highest being 760C. When the reactions

proceed in the correct order all the solid reactants are regenerated, except water which is

split into hydrogen and oxygen and separated from the system. The flow schematic of

the UT-3 Thermochemical process is shown in Figure 2.1 below and the reactions are

enumerated below:

VOLUNFTRIC NXI













Figure 2.1 Flow Sheet of the Solar UT-3 Thermochemical Process (Sakarai et al., 1996)


The UT-3 System starts with water being pumped into the system <16>, heated

into steam in HXO1, and pumped into the reactor R1 where reaction (2.1) occur with









CaBr2 to generate HBr. This reaction is reported to take one hour to reach equilibrium.

Surplus steam along with other gaseous products (primarily HBr) is routed to reactor R4

where reaction (2.4) takes place with the release of H2 and additional HBr.

(Reactor R1, 7600C) CaBr2+H20(g) -CaO +HBr(g) (2.1)
(Reactor R2, 570C) CaO+Br2(g)4CaBr+.502 (g) (2.2)
(Reactor R3, 2200C) Fe304+8HBr(g)43FeBr2+4H20(g)+Br2(g) (2.3)
(Reactor R4, 560C) FeBr2+4H20(g)4Fe304+6HBr(g)+H2(g) (2.4)


Hydrogen is separated from the main process stream at Si. The balance flow

primarily containing HBr reacts with Fe304 in reactor R3 to form Br2 as shown in the

reaction (2.3). Br2 then reacts with CaO in reactor R2 to release 02 as shown in the

reaction (2.2). 02 is separated in S2 and the balance of the stream flows with the make-

up water, at <16>, back to reactor 1 completing the cycle.

The prominent features of the process path are listed below.

1. Only water is fed through the stream <16> which is consumed and split into H2 and
02.

2. Reactors R1 and R4 hydrolysiss reactors) produce H2 and Reactors R1 and R2 and
R3 (bromination reactors) produce 02.

3. The products of reactors R1 and R4 are reactants in the reactors R2 and R3
respectively. As reaction equilibrium is reached in the reactors, the flow direction is
reversed, where reactors R2 and R3 now function as the hydrolysis reactors
(producing hydrogen) and reactors R1 and R4 serve as the bromination reactors
(producing 02). This switch over approach can be repeated multiple times for
continuous operation.

History of Research on the UT-3 Thermochemical Process

Through the years the reactions and process have been studied extensively by

groups in Japan. The UT-3 process may have potential as a means to commercially

produce hydrogen in a carbon free and energy efficient manner. However, in order to









evaluate this potential, a number of different aspects of the UT-3 process have to be

investigated. For discussion these aspects are categorized into process and simulation

studies, membrane and separation techniques, iron solid reactants, and calcium solid

reactants.

Process and Simulation Studies

The first investigation (Kameyama and Yoshida, 1978) examined the Gibbs free

energy of each of the reactions in the UT-3 process. An experimental set up was reported

but no significant system study was made.

In 1981, a conceptual design of a large scale UT-3 thermochemical process

hydrogen production plant to be coupled with a high temperature nuclear power plant

was given (Kameyama and Yoshida, 1981). The facility would include three main

sections (Figure 2.2). The first two consisting of a reaction tower for the calcium

reactants and another for the iron reactants. The third section would be a tower for heat

exchangers to bring high temperature heat to the reactors and recover waste heat from

other reactors. The design includes a provision for using solid reactants in the form of

honeycomb-shaped tubes with inert materials as binders. The honeycomb-shaped solid

reactants would be put into a fixed bed reactor. The reactions can occur along

honeycomb channels isolating the process stream from the reactor walls. Thus this would

eliminate the need for expensive materials of construction such as titanium. In this paper

a simulation was also done to determine the reaction zone as well as investigate heat

exchanger design.

Results from the performance of the MASCOT (Model Apparatus for Studying

Cyclic Operation in Tokyo) bench scale UT-3 plant were reported in 1984 (Nakayama et

al., 1984). Most of the paper focused on the experimental setup for the MASCOT plant









(Figure 2.3). The plant was designed to produce 3 normal liters of H2 per hour. It was

run for 2 cycles with a peak performance of 2 normal liters per hour (Figure 2.4).


Figure 2.2 Conceptual Illustration of Whole Plant (Kameyama and Yoshida, 1981)

A change in the process flow was subsequently introduced so that the HBr from

reaction 1 would not have to be separated from surplus H20 before entering reaction 4

(Kameyama et al.,1989). Rather the HBr is carried through reactor 4 and proceeds to

reactor 3. Figure 2.5 shows the original (a) and the modified schemes (b). The modified

scheme reduces the flow complexity found in the original process.











vslve tor
____________________


i'ir
S- q
I-Il--ii


I 1 '111 ,I ,
Si -
I '2 ,--


r;
i




K --
(; I


3 L H HYDROGEN PRODUCTION PLANT


Figure 2.3 Illustrative Diagram of the MASCOT Plant (Nakayama et al., 1984)


Firsi


2,0


- 0-I-4--


~.1'~le -~








U
9'


1 20 1


2 0


~r- Sezoond c., ~le -;s


20


*
*


1
J


ReactLon time [hi
Figure 2.4 Time Histories of the Rate of Hydrogen Production (Nakayama et al., 1984)


j IIL1


KY


I i .

"11" I L1


I


I


'r -t re-contraler Banel


/-1. ..II
1-i


I' "r'i


-


5.~ 1


0O











HO, HBr H20, HBr


:-- H20--- F------
^ c, C.:E.- + H20



CoBr M- I 3 Br: +4H2O H20 3 FeBr- + 4 H-0
x.'" + 2 HBr -FeO04+ 6HBr + Hn Hr ~-FeO + 6 HBr + HZ HBr









-CIBr +1/2 02 -3 Fe 0 + B -Co 1/2 03 FBr + 4 HUC + Ba,



(a) (b)


Figure 2.5 Original (a) and New (b) Flow Sheets of the UT-3 Process (Kameyama et al.,
1989)













T -

'. "a B- (2.5)


HH2 is the energy per unit time of the hydrogen produced in the plant, at the

higher heating value in MW. HHeis the Input heat to the chemical process from the high

temperature gas reactor (HTGR) plant by helium gas in MW. HRis the heat recovered in

MW. Pc is the power consumed within the plant in MW and 860.6 is a conversion

factor. lSe is the power generation efficiency, which means the efficiency of the
factor, rqsP is the power generation efficiency, which means the efficiency of the










conversion of recovered heat into electricity or for driving steam turbines. TITis the

overall total efficiency as defined by Aochi et al.


Pule Wraterl


-z---T.!EtbJe Heat of r:jg and Oxygen)
+ (Cooler Du':--
Power encrt-rt~r. Eff zFLen7 of
SStedm rSF a 0.30


Net Heate ieat 3
Pcqx.:,I6


Power Loss


(Unit: MW)


Figure 2.6 Energy Balance of the UT-3 Hydrogen Plant (Aochi, et al. 1989)

The MASCOT was operated with the new flow scheme for 11 cycles

continuously (Sakurai et al., 1992). It was found that there was close to a 2 to 1 ratio

between hydrogen and oxygen produced. The system appeared to operate steadily

though slight fluxuations existed. The yield seems to be lower in this experiment than

that reported in 1984 by Nakayama et al. but the cyclic run time is not given for this

experiment. The run time for the other cycles was approximately 2 hours though, so it

would seem that the run time would be at least 1 hour and that the yield would be around









1 to 2 liters per cycle. It is thought that the new flow scheme would not affect the

hydrogen output so drastically. The reason for this discrepancy is unknown, though cycle

times of only about 10 to 20 minutes would reconcile the two sets of data.




0.4 H
2

03


0,2 m I .. .. r -






1 2 3 4 5 6 7 8 9 10 11

Cycle number [-]

Figure 2.7 History of Total Gas Production by Cyclic Operation (Sakurai et al., 1992)

Most of the research from 1996 onward focused on simulations of the UT-3

Process. In 1996 Sakurai, Bilgen et al. published 2 papers. The first discusses the

possibility of using a solar concentrator to supply the heat for the cycle. They conclude

that it will be feasible to operate with a thermal storage unit and 24 hour operation. The

second discusses an adiabatic model of the UT-3 Cycle. A computer simulation is run

and first and second law efficiencies are found to be 48.9% and 53.2% respectively. The

next year a technical evaluation of an industrial scale plant for the UT-3 thermochemical

cycle is reported by Tadokoro et al. (1997). The main focus of the paper was the

improvement in the overall thermal efficiency with membrane separation. Figure 2.8

illustrates their predicted efficiencies. They concluded that the use of a membrane for











separation will increase efficiency and therefore improve the economics of hydrogen


production by the UT-3 thermochemical process.


45 I-


0.25 0.30 0.35
Power Generation Efficiency, 1_


Figure 2.8 Thermal Efficiency of UT-3 Hydrogen Plant Having Membrane Separation
(High Heating Value Basis) (Tadokoro et al., 1997)


After 1997 there is not much published on the UT-3 process. Teo et al. (2005)


carried out an analysis on the UT-3 process efficiency. Their analysis included practical


considerations of equipment efficiencies (compressors, heat exchangers), separation


membranes and associated pressure loses, incomplete conversions for the reactions, low


temperature heat, and the impracticality of isothermal operation in the iron reactors.


/
/




Application of 7
membrane with high irwovery rate
/
/
/








Application ofof
membrane with lowe
recovery rate / /
1 0

I



/ No application
of membrane





S- --. By crediting the surplus
low level heat


401-









Their value for process efficiency from solar heat was less than 7%. To give more

credibility to this paper, in the postscript the authors tell of feedback from the research

and development community that indicated it is well known that the efficiency of the UT-

3 thermochemical process is much lower than claimed by original researchers. The

authors indicated that this has not been published in a public domain until now. They

also indicated that other thermochemical processes should be evaluated in a similar

manner to weigh the questions: Should work be done on these processes? And if so

which ones?

Membrane, Separation Techniques, and Materials

One of the most important factors affecting the energy efficiency of the process is

the separation of hydrogen and oxygen from the process stream. The hydrogen is

produced in a reaction with a temperature of 570C. Hydrogen has to be separated from

stream containing hydrogen bromide and nitrogen or steam (used in excess). Separation

can be accomplished (if nitrogen is not used) by condensation of water and hydrogen

bromide. This, however, is highly energy inefficient means of separation since this

condensed stream has to be reheated before it is sent to the bromination reactor R3

(Figure 2.1).

Alternatively, research has focused on developing high temperature corrosion

resistance ceramic membranes to separate hydrogen from the other gases. This has also

proven difficult because of the incompatibility of hydrogen bromide with most membrane

material. The list of hydrogen bromide compatible materials is further shortened due to

the high temperatures at which desired separations should occur. The pressure drop

across the membranes is high and the separated H2 has to be compressed which required

additional energy.









To meet these needs a zirconia-silica composite was studied for the separation of

hydrogen (Ohya et al., 1997, 1994). The study found that hydrogen bromide and steam

were able to permeate the membrane much more than the hydrogen. Thus the hydrogen

could be separated in the reject stream and the hydrogen bromide and water could be

separated out through the membrane. Separation factors between 6 and 36 were obtained

using different pressure gradients and temperatures ranging from 423K-773K (2500C-

5000C). The HBr-H20-H2 separation was also investigated by Morooka et al. in 1996.

The approach used an a-alumina support with a silica membrane and was tested up to

4000C with effective results. The hydrogen bromide could not pass through the

membrane and the separation factor between hydrogen and water was over 100.

Though these membranes still do not function at the reaction temperature of 570C they

allow for a much more energy efficient separation of hydrogen.

Materials for piping and other parts also need to be considered. Not many

materials can withstand the corrosive components such as Br2 and HBr at such high

temperatures. Titanium would work but the cost is too high to make the system

economical to produce hydrogen. Ceramic materials are also being developed for use

with the UT-3 cycle. Sasaki and Hirai (1994) coated stainless steel with TiC-SiC film

using vapor deposition techniques and tested it in a Br2- 02- Ar environment up to 8000C.

The temperature was cycled between 5000C and 8000C. Corrosion was still present but

greatly reduced.

Another proposed plan to reduce materials of construction cost is to run the

system with excess steam or nitrogen or a mixture of the two. This is what is currently









done in the UT-3 process. No reports of corrosion problems appear in the literature,

though it is suspected that corrosion may occur over time.

Solid Reactants

A pellet form has been chosen to meet the strength and reactivity demands of the

cyclic UT-3 process for both the iron and calcium reactants. Even in the first proposal of

the UT-3 process Kameyama and Yoshida (1978) emphasized the importance of

developing durable solid reactants. Their development and improvements are outlined

here.

Iron reactants

In 1978 Kameyama and Yoshida tested three supports for the iron

reactants. These supports included 120 micron glass beads, Bentonite (a type of clay),

and Kaolin (high quality clay used to make china). The pellets were made into 15mm

spheres. The bentonite supported material seemed to have the best conversion to FeBr2

which was about 45%.

In 1981 Kameyama and Yoshida reported on their studies of the iron solid

reactants and their chemistry. The iron oxide pellets were made by mixing Fe304 and

silicasol (Cataloid-S-OH), adding a saturated solution of ammonium carbonate, then

drying, molding, and calcination. It was reported that reaction 3 was found to be

composed of two stages represented by

Fe304+2HBr Fe203+ FeBr2+H20 (2.6)
Fe203+6HBr 2FeBr2+3H20+Br2 (2.7)

Taking into consideration the mass and heat transfer resistances from the gas film,

product layer and surface chemical reaction these researchers came up with two equations

for reaction rates for different temperature regions. The reaction rates use the shrinking








core and assumed to precede topochemically. These reactions are shown here in Eq. 2.8

and Eq. 2.9 where a is the surface area of the reaction in cm2

r3s 38.2a(CFe304 0015-(.CHB (210C-255C) (2.8)

8 fS13.0
r3-s= 1.7810 -8exp 13 -*a-. (C 04 -.00150)-(CH 5
3 -RTO [ [ (255C-300C) (2.9)

A more detailed iron pellet formulation procedure is given by Yoshida et al.

(1990). Figure 2.9 shows an outline of this formulation along with that of the

contemporary calcium pellet formulation procedure of that time. The reaction rates of all

four reactions were also evaluated experimentally. A tabulation of these rates can be

seen in Table 2.1 below.

CaCO3 powder Fe304 powder
T02 powder SiO2 So lution (30 wt%}
Graphrte powder H20 ZrO2 powder
S Mixing / Cellulose


Kneading
I
Extruding into cylindrical form

Forming into spherical pellets

Drying at 80C

Calcination at 11 00C Calcination at 1200C
CaCOW CaO Fes 04 'Fe 20

Figure 2.9 Process for Pelletizing Solid Reactants (Yoshida et al. 1990).
Table 2.1 Comparison of Initial Rates of the UT-3 Thermochemical Process Yoshida et
al. (1990).











Reaction Gas Solid Reaction
temp. concern concen constant Rate Initial rate
Reaction CI C C[mol m 1 C(mol m-'l k equation [mo1 as m '
CaO+ti -*i +1/20 550 4 34x 10' 462 x l10 r kCo C, 53
CaBr2 + ,-I. --*CaO + 2HBr 700 251 3.45 10 6. l10 10 r = kC(.HC~o 53
81 222
I. i + IiBr-IrI- +.t i + Br, 220 19 120x0' 2.25x10 r-kCeo Car
580 286 3.60 x 10 4.28 x I0 569
F..., +4H 0 -. *.,+6HBr+ I. 400 362 360x10' 3.12x104 r= 53

Total pressure = 20 atm.



In 1992 another paper was published on the procedure of making the iron

pellets (Amir et al., 1992). The paper highlights the use of graphite to increase porosity


by more than 5 times. Specific pore volume with no graphite was .06 cc/g and was

increased to .35 cc/g when 20% by weight graphite is used. Figure 2.10 shows a linear


relationship between the total cumulative pore volume and the percent of graphite added







E 02 T I
l0 L -----------1L----------I----1---------
0I"-






0 5 10 15 20 25
Add. i.. graphite content I|wt%

Figure 2.10 Relationship Between Pore Volume and Additive Graphite Content in Pellet
(Amir et al., 1992)

In 1993 Amir et al. published results comparing 8 different ceramic supports for


the iron reactants. The analysis included the chemical composition, hardness, porosity,


and reactivity of the pellets. A Table of the results can be seen in Table 2.2 below.

Degradation of reactivity occurred over a number of cycles. It was concluded that some


FeBr2 sublimes at the high temperature of the reactions. This reduces the iron content and

also plugs the pores as it leaves. There is also agglomeration of iron oxide particles










which reduces surface area and damages the structure of the pores both of which have an

adverse effect on reactivity. This is the last study which focused on the iron reactants.

Table 2.2 Properties of Calcined Iron Solid Reactant Pellets (Amir et al., 1993)
Raw material Mole ratio Density Iron content Hardness Pore volume
Pellet Reactant Sjpp'n Fe rZr Sio ITZ-Y) kq m ) Imol mni :
1 FetO4 SiO2 + Z 0, 1:4.2:4.2 18 x 10 5.4 x 10' 8 0.45
2 F[e04 Z rSIO. 1:4.2 1 8 x 10' 5.4 x 10' 8 0.35
3 FeeO0 TZ -3Y 1:4 37 x 10" 15.2 x 103 II 0 12
4 FeC04 TZ-8Y 1:4 3.6 x 103 14.3 x 10' 17 0.12
5 I, .O.'FP) TZ-3Y 1:4 1.7 x 103 6 9 x 10' 9 -
6 FeC, -Oi TZ-3Y 1:4 1.6 x 10' 6.5 x I.' <1 -
7 F.C ,ll.,O TZ-3Y 1:4 89 x 10~ 3,6 x 103 <1
8 FC H,11, N3 TZ-3Y 1:4 I.3 10' 5.6 103 <1 -



Calcium reactants

The reaction rates of reactions 1 and 2 were reported in 1989 (Kameyama et al.)

and then again in 1990 (Yoshida et al., Table 2.1 on previous page). Kameyama et al.

(1989) used X-ray microanalyzer and found that after the bromination reaction calcium

bromide was equally distributed throughout the pellet confirming their prediction of a

homogenous reaction.

Table 2.1 give the findings of Yoshida et al. (1990). The formulation of the

calcium pellets was first reported by Yoshida et al. (1990). It is thought that this

procedure had been used for a number of years before but only reported in 1990. Figure

2.9 above outlines this procedure. The process uses a mixture of calcium carbonate and

titanium dioxide with some graphite. The mixture is made into pellets and heated to

11000C so that the calcium carbonate loses CO2 leaving CaO, the needed solid reactant

(Eq. 2.10). At this temperature some of the calcium oxide will also bond with the

titanium dioxide form calcium titanate (Eq. 2.11).

CaCO34 CaO +CO2 (2.10)

CaO+TiO2- CaTiO3 (2.11)









Metal Ca C2H5OH



Ca(OC2H5)


Ti(OC3H7)4 Refluxing


Graphite Powder -


LO0 Hydrolysis

Precursors

Filtration
Molding
Calcination

CaO CaTiO3 Pellet

Figure 2.11 Production Process of the Pellet Using Ca and Ti Alkoxide
(Aihara et al., 1990)
A new method for fabrication of calcium pellets was reported in 1990 by Aihara

et al. This method uses alkoxide chemistry to create calcium titanate and calcium oxide

(Figure 2.11). Pellets were made from both the old and new methods and their
performance in the cycle was compared. The new method had a much higher reaction

rate which reduced the time to maximum conversion. This can bee seen in Figure 2.12
below.















I1 -

I- -_ -- -I

iin:r'
0 10 20 0 '1o 240 0,Al



Figure 2.12 Solid Conversion Profiles of Bromination (left) and Hydrolysis (right) by
Cyclic Operation (Aihara et al., 1990)

In the new pellets the calcium oxide was distributed in smaller particles in a more

even arrangement. This reduced pore clogging significantly and therefore decreased the

conversion times. Figure 2.13 illustrates the reduction in pore volume after one run for

the old and new methods respectively.

Figure .13 r-i-eT i -D--i t-r-i b ru i i UE (u)1 n Brmil t I ---lret--r Made
.., ', -r r:- h r,- ,-T'r1T -rfri

: 1 I

1 2
0 8



o -i nl i ii I L.i.J i Il I I I .I 1
OaW1 a 1 10 00 1 11 i 10 'ij
,,r. *, ,t.i-I, t..-fr i r ,t i i P..rC* .'1.-,'3] )I ( | nr


Figure 2.13 Pore Size Distribution of Unreacted (u) and Brominated (b) Pellets Made
from the Old Method (Left) and the New Alkoxide Method (Right) (Aihara et al., 1990)

In 1992 Sakurai et al. studied the rates of reaction with the pellets made using

alkoxide chemistry. The reaction rates were proportional to first order of both the

bromide and calcium oxide concentrations. It was also found that bromination (Eq. 2.2)









should take place above 590C to prevent formation of by products, though these by

products are not specified.

In 1995 Sakurai et al. reported another significant improvement in the formation

of the calcium oxide pellets. A very similar approach to Aihara et al. was taken but a

dispersion chain of chemistry was added. The same alkoxide chemistry was used to

create the calcium titanate. Then another formulation was added to make very small

particles of calcium oxide. This separated the synthesis of CaO and CaTiOs in two

processes and then the mixing of the two form the final product. The CaO particles are

much smaller than those produced from the previous method and better dispersed in the

CaTiO3 matrix. An outline of this procedure is shown below in Figure 2.14. The left part

of the Figure is the calcium oxide dispersion chain.

:' + ..\ 'It + I" .- II:, -"lil I "




SI Ir: l,:..r



|^.'.'.l_ L .Ul

TI 1 1


''' II "r I'l"
-- .. ...


T 7 :r' .i,:-1




Figure 2.14 Flow Chart of a Modified Method for the Preparation of a Pellets Using
Alkoxide Method with a Dispersion Chain (Sakurai et al., 1995)










Again pellets were made by both methods (conventional and modified) and their

performances were compared. The conventional method refers to the first alkoxide

chemistry method outlined above in Figure 2.11 above and the modified method refers to

the alkoxide chemistry method with the dispersion chain outline in Figure 2.14 above.

The most dramatic improvement can probably be seen in the rates for hydrolysis (Figure

2.15). Though there is improvement in the bromination it is insignificant compared to the

increase in rate of hydrolysis. The production is governed by the slowest reaction

hydrolysiss reaction). The improvement in the hydrolysis rate therefore improved the H2

production rate significantly.






rti .:I 0.n
1 32

00 -- ------ ----------
oxide to calcium titanate on the conversion. rrOf the four ratios tested tlhe .76
CaO/CaTiO3 had the highest conversion at about 80% conversion. Figure 2.16 shows

their data.
,. .r~ ,,.,r,.- X 0.4 \



0 2 4 6 8 1o 0,0
S .50 100 150 200 250
L^ir, [ l,, fime I mini

Figure 2.15 Comparison of the Solid Conversion Profiles of Bromination (Left) and
Hydrolysis (Right) Between the Conventional Method (Alkoxide) and Modified Method
(Alkoxide with Dispersion Chain) (Sakurai et al., 1995)

Sakurai et al. (1995) also experimentally found the effect of the ratio of calcium

oxide to calcium titanate on the conversion. Of the four ratios tested the .76

CaO/CaTiO3 had the highest conversion at about 80% conversion. Figure 2.16 shows

their data.








1.0 1 -i i
0,8 E -tr- -
0.6 ;
X 0,.4 C ) Ex,.,.au --- :CICO.I-
0i2 a .io.rCj -o c.iiO le
O02
0,1-*1E.---L--iJ-~--i---It~
2 4 6 8 10
time [min ]

Figure 2.16 Comparison Between Computed and Observed Time Histories of
Bromination (CaO/CaTiO3= .45, .76, 1.01, 2.01) (Sakurai et al.,1995)
Sakurai et al. (1996) reported results from an in-depth study on porosity of pellets

made from the alkoxide method (Aihara et al., 1990). These pellets were subjected to a
number of cycles and the porosity was measured after each cycle (Figure 2.17). The
differential porosity from .01 pm to 354 pm is shown (Figure 2.18) for sample pellets

before and after bromination. It can be seen that most of the pore volume in concentrated
in the 1 to 5 micron range. This was the latest significant data published on the calcium

pellets.

0.025 .... i i ....-


0.02 1
SB I H1
0.015 B2
SE H2
S 0.01 .e H3
1 0.005
n |L 1EU2


0.006-0.5 0.5-400
Pore diameter [ rm]
Figure 2.17 Change of Pore Volume in Cyclic Operation (U; Unreacted, Bl and B2;
1st st nd rd
After 1st and 2n Bromination, H1, H2, and H3; After 1st, 2 and 3r Hydrolysis,
Respectively) (Sakurai et al., 1996)


Flat










.O.1 35 | 1- ................. i -- | --

S03G3 I i Unreated -


> 0 '125 I







1a.5a Oe -6 6cac WI)-50 SXM 10.cs
POre diarneter I'nl
Figure 2.18 Change of Pore Volume During Bromination (Sakurai et al., 1996)


Throughout these Studies, the Hydrolysis of CaO (Eq. 2.1) is rate limiting. It

determines H2 production rate in the UT-3 process. It is also the highest temperature

reaction. The current study therefore attempts to formulate CaO pellets with more

favorable characteristics.

Strengths and Weaknesses of the UT-3 Thermochemical Process

The UT-3 thermochemical cycle can be a commercially viable process.

Simulation indicates that it is energy efficient and can become cost competitive as the

prices of fossil fuels rise. The process has relatively low temperatures for a

thermochemical process which can be achieved through solar concentrators or through

helium from high temperature nuclear reactors. If the heat for the process is supplied in

this manner no carbon dioxide will be produced. Another advantage of the process is that

the solid reactants remain stationary in the reactors eliminating the need for moving bed

reactor which would otherwise add a great deal of operation complexity.

There are weaknesses of the UT-3 process as well. The process is in batch mode

and is limited by the slowest reaction which is about 1 hour. There are still problems that









have to be solved in hydrogen separation at high temperatures from corrosive gas. This

problem, however, is inherent in most thermochemical cycles. In addition both the

calcium and iron pellets need to be durable and have a cyclic life that would make them

economical. This may be a major drawback of the process. Despite these weaknesses

the UT-3 thermochemical process is one of the two non-hybrid cycles being studied, the

other being the General Atomic process mentioned earlier.

Teo et al. (2005) were skeptical of the possibility of the UT-3 thermochemical

process as a feasible means to produce hydrogen. They did an analysis which predicts a

much lower efficiency of less than 7%.

Calcium Oxide Solid Reactant

When designing a solid reactant for the UT-3 thermochemical process a number

of characteristics had to be considered within the confines of the process. The UT-3

thermochemical process is cyclic. A solid reactant that can continue to react from one

cycle to the next had to be designed. UT-3 researchers selected a pellet configuration

where the solid reactants were dispersed on a solid porous substrate. Such formulation

prevents the carry over of solid reactant in the gaseous stream. Proper formulation of a

porous substrate and high dispersion of the solid reactant can increase the conversion and

improve the reaction rates. A pellet form of solid reactant with minimal degradation can

also be used in a standard fixed bed reactor. Many interdependent physical and chemical

processes will be considered when designing the pellets.

The design characteristics which need to be considered are similar to those

considered when designing a catalyst. These characteristics are interdependent so that

they need to be considered together and cannot be isolated to a large degree. These

characteristics and their interdependencies will be discussed below.









Physical Characteristics

Physical characteristics refer to those properties that have to do with the physical

geometry and mechanics of the material. Porosity and strength are two important

physical characteristics that must be considered when designing the pellets.

Porosity

Porosity is the term for the characterization of the pores of a material. The

porosity of a material is explained using a few different statistics. The first is the total

surface area which is important because it is proportional to the number of available

chemical reaction sites. The second is the pore size which affects the diffusion rates

through a material. All these parameters can be correlated using the BJH equation to

manipulate isotherm data which will be explained in the analytic research tools section in

Chapter 4. Thus a pore size distribution can be created. This allows the researcher to

understand what size pores are in the material. Pore sizes have been split up into two

groups. Microporosity describes pores smaller than 0.5 ptm whereas macroporosity refers

to pores larger than 0.5 pm. Macropores contribute to diffusion characteristic inside the

pellet while micropores increase the surface area on which the solid reactant can be

dispersed. Macropores are also necessary to prevent plugging of diffusion path due to

volume change of the reactants during the cyclic process.

Strength

The strength obviously refers to the strength of the pellets to resist disintegration.

Strength of the pellets must also be considered with the thermal shock that comes with

the cyclic oscillations of the UT-3 process. Strength also refers to the ability of the

material to keep its porous structure intact on a micro level. The "micro" strength helps to

prevent reduction in pore surface area and pore volume. Further, the pellets must support









the weight of other similar pellets. If they are crushed within the fixed bed they will

cause a higher pressure gradient in the reactor leading to a lower flow rates and greatly

reduce reaction surface area leading to lower conversion.

Chemical Characteristics

Chemical composition

Chemical composition refers to the chemical make up of the final pellets. This is

important in this particular application because one of the components, calcium oxide, is

a chemical reactant. Generally, reaction rates are proportional to the concentration of

reactants, thus a greater concentration usually yields a higher reaction rate. The solid

reactant, calcium oxide should be maximized but must be balanced with the characteristic

strength of the pellet, especially on the smaller scale. The calcium titanate forms the

porous substrate on which the calcium oxide is dispersed. If these structures collapse the

surface area is greatly reduced and thus the reaction rates are greatly reduced.

Reactivity

Reactivity refers to the ability of the solid reactant, CaO or CaBr2, to react with

the gaseous reactant, Br2 or H20 respectively. This parameter depends on the surface of

the solid reactant that is dispersed and the diffusion path to the solid reactant and out of

the pellet. The reactivity is highly dependent on the porosity of the material as both

overall surface area and diffusion rates are determined from porosity. Reactivity can also

depend on the concentration of the reactant and so the amount of reactant should be

increased as much as possible without sacrificing the other needed characteristics

especially the strength. The rate of reaction and conversion are the main measure of

reactivity. The reaction rates are generally dependant on concentrations of reactants and

products and temperature. Conversion is a quantity to describe the extent of reaction.









Temperature, pressure, reaction rates, type of reactor, and concentrations all have an

effect on the conversion.

Degradation

Degradation refers to the loss of reactivity from cycle to cycle. This can happen

in a number of ways. Degradation is usually due to pore clogging or pore structure

breakdown. Pore clogging occurs when larger particles react and bond to a site formerly

occupied by a smaller particle. The molecules volume of CaBr2 is greater than CaO

which could lead to pore clogging after the bromination reaction. Pore clogging can also

occur do to growth of agglomerates which usually happens at high temperatures through

sintering. Pore structures can breakdown due to external forces (fixed bed weight) and

also small forces from the gases entering and exiting and molecules forming and

reforming break the bonds which maintain the integrity of the pores.

Research Objective

The objective of the research project at the University of Florida is to investigate

the feasibility of the UT-3 thermochemical process and explore the possibility of

lowering the operating temperature. The highest temperature reaction is reaction 1 (Eq.

2.1) at 7600C in which CaBr2 is converted to CaO. Solid reactants with acceptable

characteristics must be developed to evaluate the performance of the UT-3 process. This

research is therefore focused on developing the solid reactant for the calcium reactions

(Eq. 2.1, 2.2).

The objective of the present research is to develop a method of producing the

calcium solid reactant for the UT-3 process. The solid reactant will be made into pellets

for our research. It is a common practice to make catalyst into pellet materials for use in

fixed bed reactors. Pellets provide a good surface area, low degradation, and even









transport of gaseous reactants and products through the reactor. Though the solid

reactants are not catalysts in the UT-3 process, pellets are a good choice for the form of

the solid reactant. If designed and fabricated correctly they can provide the same benefits

as in a catalyst system.

There are many steps that need to be taken in order to create pellets for the UT-3

thermochemical process. A summary of the strategy to make the pellets is presented

below for both the chemical formulation and physical procedures. Both will again be

explained in greater detail in the procedural section.

Chemistry Formulation

A chemical procedure will be used to make two different sizes of agglomerates.

The first will be larger particle of CaTiO3 and second will be the smaller will be CaO. In

the final formation the larger agglomerates will have space between them which will

result in macroporosity. These larger agglomerates themselves are not solid though.

They have microporosity as well. In this way the pellets will have the bimodal porosity.

The smaller agglomerates of CaO will be dispersed into the micropores which will give a

good reaction area for the pellets while at the same time maintaining the macroporosity

needed for diffusion.

This chemical procedure is complex. The CaTiO3 agglomerates must be made

big enough to create the macroporosity in the pellet. The agglomerates themselves

should have microporosities for CaO dispersion. The CaO particle must be very small in

order to be dispersed into the micropores of the CaTiO3 and not clog them. Parameters

which will be examined are mixing ratios and heating procedures. The effect of these

parameters will be evaluated by porosity, strength, and chemical composition

measurements.









Physical Formation

After the chemical procedure is developed and mixture of CaTiO3 and CaO

obtained, the mixture must be formed into pellets. The precursors must be dried to a

solid powder form. The powder then will be molded in a compression mold to create

pellets. The pellets will then be heated to a temperature to achieve controlled sintering

and adjust the porosity distribution and strength of the pellets. Parameters which will be

examined are mold compression force, drying temperature, sintering temperature and

duration. Porosity and strength will be the dependent variables by which the effect of

these parameters will be evaluated.














CHAPTER 3
SOLID REACTANT

Presented in this chapter are the procedures to produce the precursors for pellets,

including the original chemical formulation, the modified chemical formulation used by

UT-3 cycle researchers, and the physical method to mold and treat the pellets. There

have been several problems during the course of the work leading to a number of changes

to both the chemical and physical procedures. These problems, their causes, and

procedural changes are also discussed in this chapter.

Sol-Gel Chemistry

The sol-gel process is an approach for preparing thermally, chemically, and

mechanically stable materials with controlled porosities used in the area of gas

separation, catalysis, membrane reactors, sensors, and absorbents. Starting from a

molecular precursor (sol), an oxide network (gel) is obtained via inorganic

polymerization reactions. These reactions occur in solution and hence the term "sol-gel

processing" is used (Brinker and Scherer).

As compared to the conventional "powder" route these processes offer many

advantages:

1. Homogeneous multi-component systems can easily be obtained by mixing the
molecular precursor solutions with better kinetics and yields.

2. The scale of mixing is considerably smaller which enables greater dispersion

3. The temperatures required in sol-gel processes are markedly low.









4. Careful manipulation of operating parameters (temperature, pH, water content)
can yield products suitable for diverse applications.

5. The deformation properties of the sol or gels allow the formation of fibers, films
or composites by such techniques as spinning, dip-coating or impregnation.

An alkoxide is "an ionic compound formed by the removal of hydrogen ions from

the hydroxyl (OH) group in an alcohol using reactive metals." (Frostburg) The alkoxide

used in the current chemical process is calcium ethoxide (Ca(C2H50)2) Metal alkoxides

M(OR)n are versatile molecular precursors for the sol-gel synthesis of metal oxides.

There are known alkoxides from many metals including the transition metal elements.

The difference in transition metal sol-gel chemistry compared to the rest of the metal

elements arises from two factors:

* The higher electropositivity of transition metals leads to a much higher
electrophilic characters of the metal.

* The possibility exists for most transition metals to exhibit several coordinations so
that full coordination is usually not satisfied in the precursors (alkoxides). This
increases the probability of adding ligands to the transition metal ion which leads
to diverse physical and chemical properties.

As a result, transition metal alkoxides are much more reactive. They must be

handled with care, in the absence of moisture. They readily form precipitates (particles)

rather than gels (networks) when water is added. The sol-gel process primarily proceeds

in two steps: hydrolysis, then condensation.

Hydrolysis

The electronegative alkoxo groups (OR) make the metal atom relatively

electropositive and therefore highly prone to nucleophillic attack. Metal alkoxides are

therefore extremely reactive with water leading to the formation of hydroxides or hydrous

oxides. The overall reaction can be written as:








M(OR)n + nH20- M(OH)n + nROH

The stepwise progress of hydrolysis is shown here (Sanchez et al., 1988).


-l-o0
I


M-OR R0 .,.M-OR
s-/


1. The first step (a) is a nucleophillic addition of a water molecule to the positively
charged metal atom M. This leads to a transition state (b) where the coordination
number of M has increased by one.


O.,MH -4s
N'I1-~


S- S "4H
H-O- MoR,
H


2. The second step involves a proton transfer with (b) leading to the intermediate (c).
A proton from the entering water molecule is transferred to the negatively charged
oxygen of the adjacent OR group.


S ." +6
H'-Ko + ^


So-r t Ro H


3. The third step is the departure of the more electropositive group within the
transition state (c).

Condensation

Condensation is a complex process and can occur as soon as hydroxo groups are

generated from hydrolysis. Depending on experiment, three competitive mechanisms

have to be considered, namely: alcoxolation, oxolation, and olation (Livage et al., 1988)

1. Alcoxolation is a reaction by which a bridging oxo group is formed through the
elimination of an alcohol molecule.

M t- S- S- E-' M -
f-o + M- R-+ M-o:M-OR--MOh- ROH
LII








2. Oxolation follows the same mechanism as alcoxolation, but the R group of the
leaving species is a proton and the leaving group is water.

S+ 8 S-1- "> S+ S h 0

H RH

3. Olation can occur when the full coordination of the metal atom is not in the
alkoxide. In this case bridging hydro groups can be formed through the
elimination of a solvent molecule (ROH or water)


-\-OK M-O-+ +RON

H

M-014 + M..0 -4 +

The condensation reaction can continue to build larger and larger molecules

through polymerization. A polymer contains hundreds of thousands of units called

monomers which are capable of forming at least two bonds with neighboring molecules.

The polymerization may result into compact particle structure or extended structure

(network). Particles can be easily molded to form pellets. High water/alkoxide molar

ratios, high pH, and high temperatures promote particle formation (Brinker et al., 1994).

Low water/alkoxide molar ratios, moderate acidity, and low temperatures promote

extended structures.

This experiment has the following expected reactions:

1. Formation of Calcium Ethoxide
Ca + 2C2H5 OH- Ca(C2H5 )2 +H2 (3.1)

2. Hydrolysis of Ca(OC2H5)2 and Ti(OC3H7)4
H20 + Ca(OC2H5)2 Ca(OC2Hs)(OH) + C2H5OH (3.2)
H20 + Ti(OC3H7)4 Ti(OC3H7)3(OH) + C3H7OH (3.3)

3. Condensation by oxalation









Ca(OC2H5)(OH)+ Ti(OC3H7)3(OH)4 (OC2H5)Ca-O-Ti(OC3H7)3 +H20 (3.4)

4. Further condesation
(OC2H5)Ca-O-Ti(OC3H7)3 + Heating CaTiO3 Network (3.5)

It should be noted that this is very complex chemistry which cannot be completely

predicted. Equation 3.2 shows one hydroxyl group replacing one alkoxo group on each

the titanium and calcium metal atoms. In actuality this reaction may occur more than

once. The number of hydroxyl and alkoxo groups shown as reactants for condensation

will also likewise vary (Eq. 3.4). Equation 3.5 simply states that more condensation

occurs through chemistry, drying, and heating which ultimately forms the CaTiO3

network.

Chemical Formulation

The chemical formulation of the precursors for the pellets is a very sensitive and

important step in the process. Sol-gel processing described above is used. Within this

method there are a number of parameters that can be changed which can greatly affect the

properties of the resultant product. These parameters include molar ratios between

calcium, ethanol, water, and titanium isopropoxide, pH, temperature, and procedural

steps. The procedures developed by Aihara et al. published in 1990 and later in more

detail 2001 were used as guidelines in the current work of synthesis of the precursors.

Qualitative investigation

A qualitative study was conducted to observe the reactions. The reactants were

mixed with each other to see what could be expected. Table 3.1 shows the qualitative

observations of this investigation. All these experiments were conducted at room

temperature in air.









Table 3.1 Qualitative Reaction Study
Ca Eth. Ti. Iso. D.W.
Calcium XXXXXXXO GWP NAR VED
Ethanol GWP XXXXXX)O WFP DFS
Titanium Isopropoxide NAR WFP XXXXXXX) SFWP
Dionized Water VED DFS SFWP XXXXX

GWP -Globular white precipitate forms (after stirring)
NAR- No apparent reaction
VED- Ca violently exothermically dissolves in dionized water producing bubbles
WFP- White fibrous precipitate forms
SFWP- Spontaneous reaction with white precipitate and gas evolution
DFS- Dissolves forming a solution

Original procedure

The procedure details given in the original publication (Aihara et al., 1990) are far

from complete. Figure 3.1 shows an outline of this procedure. This outline was followed

except graphite powder was not added. Graphite is used as an additive to increase

porosity during calcination. This parameter was eliminated at this time to increase

understanding of the other parameters affecting the porosity.


Figure 3.1 Production Process of the Pellet Using Ca and Ti Alkoxide (Aihara et al.,
1990)










Though, this procedure looks fairly easy to follow there were many difficulties in

performing the necessary steps. This first step, combining metal calcium and ethanol to

form calcium ethoxide proved to be a major difficulty. Calcium does not react readily

with ethanol. In order to try to remedy this situation two solutions were proposed.

1. Heat the ethanol and calcium mixture to see if the reaction would proceed

quicker at a higher temperature. This was done but no reaction was observed up to

boiling temperatures of ethanol. Because of the loss of ethanol to evaporation and

boiling the mixture would dry out if it was left for long periods of time. No appreciable

reaction was seen in this time frame. Later, it was found that there actually is a

noticeable reaction that occurs between 730C and the boiling point of ethanol 790C. The

reaction forms bubbles of hydrogen. This may have been overlooked as a slow boil

because the temperature is so close to boiling of ethanol.

2. Stir the solution covered to see if the reaction would proceed faster while

stirred. Again, there was no appreciable reaction observed. This mixture was left and the

evaporation rate was slower in this set up. Thus, the reaction could be observed over a

longer period of time. A white precipitate could be seen after about two days. The white

precipitate thought to be the calcium ethoxide was finally formed. The precipitate

seemed to be white and globular and settled to the bottom of the beaker after several

hours. This method was adopted as the first step of the original chemical formulation.

The amount of calcium that would react in ethanol was very small. Later through

a 10 day test the reaction limit was found to be about 0.0015g/mL. This was done by

taking 0.38 grams calcium and adding ethanol over a number of days until the calcium

was reacted. After 10 days the volume of ethanol added to react all the calcium was 250









mL. To try to increase the concentration of calcium some ethanol could be evaporated

without signs of black calcium reforming. However, other calcium compounds may have

been formed.

Next, 18 mL of titanium isopropoxide was added to 40 mL of this mixture. A

stringing precipitate was spontaneously formed. The beaker became noticeably warmer

indicating that this was an exothermic reaction. This precipitate appeared to be the same

that was found in the qualitative study of reaction between ethanol and titanium

isopropoxide (Table 3.1). The mixture was stirred for 5 minutes and the stringy

precipitate broke apart very easily.

Next the mixture was hydrolyzed using 12 mL of dionized water. The beaker

again became warmer indicating an exothermic reaction. The water seemed to react with

the precipitate forming a powder-like precipitate. The mixture was again stirred for 5

minutes.

Drying procedures described later in this chapter were then followed to eliminate

ethanol and water from the liquor leaving a powder. The powder was molded into

pellets. The feedback from this pelletization study was used to improve the pellet mold

and pelletization technique and to determine affects of sintering temperature. This

procedure was expected to yield CaO dispersed in CaTiO3 matrix. However, since the

ratio of calcium to titanium was small, it is suspected (and later confirmed via Raman

spectroscopy) that not much calcium titanate or calcium oxide was formed. Most of the

solid was anatase or rutile titanium oxide. Another indication that calcium titanate did

not form is that calcium titanate exists in different colors ranging from orange to black

but it cannot be bright white as the resultant powder was. This indicated that the powder









was TiO2 which was later confirmed by Raman spectroscopy to be TiO2 (anatase and

rutile). Thus, a new chemical procedure had to be designed. This design needed to

increase the calcium in the precursors.

Modified procedure

A paper by one of the original UT-3 authors (Aihara et al., 2001) gives more

detail into the methods used for the chemical formulation of the calcium titanate

(CaTiO3) precursor. This procedure implied that the reactions within the alkoxide

procedure are very sensitive to water and possibly sensitive to oxygen. A new setup was

constructed to perform the anhydronous formulation. The setup is shown below in

Figure 3.2.


Figure 3.2 Three Mouthed Flask on Stirring Heater









A three mouthed flask is used as the vessel to carry out the new procedure. The

first opening has a rubber stopper covered with parafilm with a tube and a mercury

thermometer. The tube is connected to a nitrogen supply and used to purge the flask with

nitrogen. The thermometer is used to monitor the temperature of the fluid inside the

beaker. The second opening has a condenser to condense any vapor that could evaporate

or boil from the system due to heating. The third opening has an adaptor with a silicon

septum. Chemicals are added through the septum by a syringe to insure an anhydronous

and oxygen free environment during the entire process. The flask is placed on a hot plate

which provides the heat for the reflux processes. All of the equipment is properly

supported using metal stands and clamps.

Aihara et al. (2001) used a nitrogen environment and followed the steps shown

below in Figure 3.3. The ratios of the reagents are presented in Table 3.2. The molar

ratios are shown with respect to Ca metal. The indicates that in step 7 dionized water

and ethanol are added in a solution.

Table 3.2 Original Mixing Ratios for Modified Chemical Formulation Procedure
Procedural Step Substance Amount Units Molar Ratio
Step 1 Calcium Metal 1.00 [g] 1
Steps 2, 4, & 7 Anhydronous Ethanol 14.6 [mL] 10
Step 5 Titanium Isopropoxide 7.4 [mLl 1
Step 7* Dionized Water 1.8 [mL] 4
Step 7* Ethanol 7.2 [mL] 4.9

The refluxing step in Aihara's, et al. procedure (step 3) was investigated to see

how long the reaction took to fully react. An appreciable reaction occurred from about

730C to about 780C. Bubbles are observed forming on the calcium. This is the hydrogen

product from the reaction shown in Eq. 3.1. In the 30 minute time that Aihara et al.

prescribe much of the black calcium powder remained though an appreciable amount of

white powder also could be seen. The reaction was watched for 5 hours without much









change. It was concluded that the reaction had reached equilibrium as no noticeable

change was observed between 30 minutes and 5 hours. Therefore, the time of 30 minutes

for step 3 was adopted.


Figure 3.3 Flow Diagram of Procedure Outlined by Aihara et al. (2001)









Stringent steps below were taken to ensure oxygen free and anhydronous

condition.

1. Clean and dry flask, condenser, and other equipment.

2. The calcium sample is measured on the electronic scale and then dropped
into the flask through the opening with the nitrogen and thermometer.

3. The Teflon stir bar is dropped into the flask through the opening with the
nitrogen and thermometer

4. The condenser and septum adaptor are coated with a thin layer of
petroleum jelly to prevent seizing before connecting to the flask.

5. The nitrogen valves are opened to allow a very small flow to the flask.

6. Water to the condenser is turned on.

7. Wait 5 minutes for nitrogen to purge system.

8. Anhydronous ethanol is extracted by syringe from its container and
discharged into the system through the silicon septa.

9. The heater stirrer is turned on to raise the temperature of the mixture to
between 720C and 760C. A noticeable reaction occurs in this temperature
range forming a white/gray precipitate. The stirrer is set to maintain good
stirring.

10. Heating proceeds for 30 minutes.

11. The mixture is diluted using the same amount of ethanol as in step 9.

12. Titanium isopropoxide is extracted from its container via syringe. The
correct proportion is injected into the flask again through the silicon septa.
The mixture is heated between 720C and 76C for 30 minutes.

13. A solution of 20% by volume of water in ethanol is made in a beaker.

14. A syringe is used to insert the water ethanol solution into the flask in
order to maintain an oxygen free environment. A reaction occurs
spontaneously turning most of the precipitate a bright white.

15. The mixture is stirred and heated for another hour. In this hour all of the
precipitate becomes white except for a small amount when the calcium to
titanium ratios are 3 and 4.









A problem encountered with this procedure was the formation of a purple rather

than white/gray precipitate forming in step 9. The problem was thought to be in the

cleaning of the flask from run to run. A new cleaning procedure for step 1 was

considered so that the chemistry would not be affected by residue in the container from

previous runs or residue from the actual cleaning agent. A rigorous cleaning was done

including both an acid bath and base bath. However, the purple precipitate again formed.

It was suggested that the rubber stoppers plugging the flask may be the problem. They

were covered with parafilm and the purple precipitate ceased to form. In the interest of

time a less thorough cleaning procedure can be used which does not affect the chemistry.

Mixing ratios

The initial mixing ratios for the new procedure came from Aihara et al. (2001).

However, that procedure was designed to make calcium titanate and therefore uses a 1 to

1 ratio between calcium and titanium. In order to also make calcium oxide more calcium

had to be used. Ratios of calcium to titanium of 2, 3, and 4 were used. Other parameters

were changed because of the equipment setup and to accommodate for the extra calcium.

These quantities can be seen in Appendix C. The original ratios used by Aihara et al. are

presented in grams, milliliters, and moles in Table 3.2 above.

Physical Procedures

The synthesized precursors were molded into pellets. A procedure was developed

which consists of first drying, then molding, and finally sintering. These three steps will

be described in detail in the following sections.

Drying

The liquor from the precursor synthesis has a significant amount of ethanol and

water left in it. The liquor is stirred to evenly distribute the particles in the container.









The liquor is poured into petri dishes. These petri dishes are set under an exhausting

fume hood. Most of the liquid evaporates off after 18-20 hours, though the resultant

powder is still slightly moist. The powder is put into a quartz crucible and heated in a

furnace to 4300C for 1 hour. It was found that pellets molded using the powder

disintegrated when heated between 3000C and 4000C. It was suspected that there were

volatiles in the pellets which contribute to the pellet failure. Therefore, a preheating step

was added. The pellets maintained their integrity at higher temperatures during the

sintering step described later. This step was necessary before molding the pellets. It also

eliminates any water or ethanol which was not evaporated in the overnight drying.

Molding

Hydraulic press

A hand pumped uni-axial hydraulic press (Figure 3.4) is used to supply the

compression force to the mold assembly. It is a Carver hydraulic model # 3912 with a 5-

1/8" maximum ram stroke. The press is located in room 1A of the Nuclear Field

Building. There are two parallel plates on the press. The upper is plate on a screw and

fixed in place using nuts. The bottom plate is connected to a hydraulic cylinder which is

raised to supply the force as the lever arm is pushed down. A force gauge on the press in

units on metric tons is rated up to 11 metric tons.

A 304-SS mold assembly (Figure 3.5) was fabricated and used in the hydraulic

press described above to make pellets of 3/16" D x 4/16"-6/16" H. Compression force on

the press was varied from 0.3 MT (metric tons) to 2 MT. Problems with plastic yielding

and seizing of the plunger with the mold were experienced at axial loads greater than 1.0

MT and so the pellets were cast with forces less than 1 MT. A step by step procedure of

this process can be seen in Appendix C.



































Figure 3.4 Hand Pumped Uni-Axial Hydraulic Press for Pellet Production


Original mold


Force From Press


Figure 3.5 Pellet Mold Assembly









The mold assembly consisted of 5 parts as shown in Figure 3.6 which are the

plate, plungers, cap, mold, and extraction piece. The plate was the bottom piece on

which the mold was supported and was the surface the pellet was compressed against. It

also helped to move the full assembly in and out of the press.






















Figure 3.6 Pellet Molding Assembly Parts

The plungers were used in two different manners and so two different length

plungers were fabricated. The shorter plungers were used to compress the pellets.

Generally, the shorter plungers had a greater compression force on them. The shorter

lengths helped to prevent bending from any eccentric forces. The longer plungers could

be used to push the pellets out of the mold and could be pulled out easily because their

extra length allowed room for gripping. The cap was the top piece which held the

plungers vertical which also helped to reduce non-axial forces which would lead to

buckling and bending. It has a hole drilled about 0.5" in depth with a 0.1875" drill bit

and a 0.1895" reamer. The mold has bores where the powder is positioned and









compacted. These bores are made slightly larger than those in the cap. The bores were

observed to expand after multiple uses at compression forces close to 1 metric ton. The

bores were made using 0.2031" drill bit and reamer. The extraction piece is only used to

extract the pellet. It is essentially a spacer between the mold and the top surface of the

press. It has is a hollow cylindrical piece which transfers the force to the outer molding

while giving no resistance in the center where the pellet is extracted. The extraction

piece allows the pellet to be pushed out into the hollow space it contains.

As discussed in chapter 2, a low compaction force is expected to yield higher

porosity in the pellet. However, lower compaction force may also reduce the strength of

the pellet. These two factors were considered to arrive at the optimum molding

procedure.

For the original chemical formulation procedure a force close to 1 metric ton gave

the best strength. Whole pellets were formed with forces as low as 0.5 metric tons but a

noticeable depreciation in strength was observed during handling the pellets. It was

found that pellets made from precursors with 0.25-2 percentage of graphite could be

made with a compaction force of only 0.3 metric tons. Also stearic acid and ammonium

carbonate were both tried as binders at 3% by weight. Both actually degraded the

strength of the pellet when compared with pellets made with the same compression

without the binders.

For the modified chemical formulation procedure a force of only 0.25 metric tons

was needed to give approximately the same strength as the pellets compressed at 1 metric

ton using the previous chemistry. No graphite or binders were used with the modified

chemical formulation.









Modifications in mold and molding procedure

Many problems were encountered during the fabrication of the mold and the

development of the molding procedure. The most prevalent operational problem was the

seizing of the plungers in the mold. This was attributed to two design aspects. The first

was the length of the mold. The original mold was 1-1/16" This original mold bore also

had a very low radial clearance between it and the plunger so that there would be

minimum flow of the powder into the space between the bore in the mold and the

plunger. The friction from the powder wedging between the mold and the plungers led to

seizing.

To eliminate this problem a procedure which limited the insertion length of the

plunger was used to prevent seizure during the compression process. The compressed

pellets however could not be removed due to the friction forces between the walls of the

mold and the consolidated powder. A slightly larger hole was drilled to see if pellets

could be made. The same problems occurred, though the plunger rarely seized during the

compression phase. When the pellets were extracted they fell apart. It was thought that

an uneven distribution of pressure in the powder along the height of the mold due to

friction led to the failure of these pellets.

A new mold was made that was 11/16" in height. The holes on this mold were

drilled slightly larger than 0.1875" at 0.2031". A procedure was used with the new mold

so that the powder would be compressed stepwise using multiple compactions. The

plunger was removed after every incremental compaction and more powder was added to

fill the hole to the top. The powder was again compressed. This was repeated until the

desired height of the pellet was reached. This process resulted in some long pellets.

However, most pellets would shear during extraction into small fragile disk shapes or









separate into shorter pellets. The seizing between the mold and the extraction plunger

also occurred sometimes.

The procedure was further modified as follows. Only one fill was used. The

powder was compressed by hand as much a possible and filled to the top. The press was

then used to compress the mold assembly with the desired force. Seizing has not

occurred using this procedure during compression or extraction. This procedure is now

used and generally produces whole pellets with the average dimensions -3/16" D x 5/16"

H though this height varies slightly from run to run. If correctly executed this procedure

yields a usable pellet every time. Seizing probably does not occur because of the

relatively short compression length into the powder at high pressures. Most of the

compression is at low pressures. Thus the powder in the gap between the plunger and the

bore is loosely packed except for the bottom. When the plunger is being extracted it has

some play in the axial direction which can loosen the tightly packed powder near its

lower face. The surface area of the plunger exposed to tightly packed powder was also

small. Similarly, during extraction the surface area of the tightly packed powder causing

the friction was reduced due to the shortened length of the pellets. Thus no seizing

occurred. The pellets hold together better also because they are compressed all together.

The previous method compresses different sections. These sections don't seem to hold

together well. Thus the current method eliminates seizing and provides a reliable way to

produce pellets.

Sintering

The pellets are sintered in a furnace to increase strength in the structure of the

pellet. An increase in temperature promotes growth of the titanium network. The

particles form intermolecular bonds which help to create a web-like structure increasing









the structural strength of the pellets. However, in the process the particles become larger,

which often leads to pore clogging. Therefore, there is an optimum sintering procedure

which will give the needed strength but without forfeiting the desired porosity.

A tubular furnace with a controller is used for sintering. An ATS (Applied Test

Systems) 3310 series furnace is used and is also located in room 1A of the Nuclear Field

Building. It can be seen in Figure 3.7 below. The furnace range is up to 13000C. The

operation of the furnace can be programmed using a PID controller (Kanthal Super 33,

PC-120/240-20 controller). The controller has an offset error and temperature set points

must be above 950C. A recalibration was done in order to try to eliminate this offset

error but it still persisted. During the calibration the error range in the temperature was

found to be plus or minus 100C. A quartz crucible attached to a quartz hanger is used to

lower the pellets and powder into the furnace. It is approximately 18" in length and the

crucible has a diameter of 1.5" and a height of 2".

There are a number of different heating schemes used to vary the temperature and

the duration of heating. The heating schemes are presented in Figure 3.8. The heating

schemes have been modified based on the behavior of the pellets with respect to strength

and microporosity. The original procedure was a 1000C step every hour up to 7000C.

This was used to first find the volatiles addressed earlier in this chapter between 3000C

and 4000C and to determine if there were any other disintegration temperatures. The

next scheme that was used went to 10000C over a number of hours. The ramp times were

to allow any reactions to occur slowly so they would not to break the pellets. The slow

ramp increase was also to prevent thermal shock from breaking the pellet. After 1000C

heating the porosity of the pellet was only about 3% of that of the 7000C pellet. However,








60



the 10000C heated pellet was stronger than the 7000C pellet. A medium temperature


above the reaction temperature of 7600C was sought that would increase strength yet give


a better porosity. Both 8000C and 9000C heating schemes were then used to investigate


this parameter shown in Figure 3.8 as the medium schemes. The results in chapter 5 show


acceptable characteristics within these temperatures.


Figure 3.7 Furnace Used for Sintering Process


1n00


1000


800


600


400


200


0


I







_,"0 fStep Heating to Discover Volatiles
Su -E -Reduction in Porosity 1000C
Medium Scheme to 800C
-x Medium Scheme to 900C


0 2 4 6 8 10
Time [hrs]


Figure 3.8 Heating Schemes for Pellets


12 14 16


18 20














CHAPTER 4
ANALYTICAL TOOLS

The theory and procedures for the analytical tools used are presented in this

chapter. The theory presented in this chapter is meant to give an understanding of some

of the methods used to characterize the pellets. The procedure is an outline of the steps

taken for each instrument to give a basic understanding of its operation. More detailed

procedures can be seen in Appendix D.

Presented in this chapter are three analytical tools. There are two porosity tests.

The first, Nitrogen Adsorption, measures micropores using theory to predict distribution

of pore sizes between 2 nm and 0.1 pm. The second, called Mercury Porosimetry,

measures macropores using mercury under pressure and theory to predict distribution of

pore sizes between 2 nm and -100 am. Though mercury porosimetry can intrude into

small pore sizes, BET measurements are generally taken as a better measurement of

micropores smaller than 50nm. The third tool is Raman spectroscopy which is used to

determine the chemical composition of the pellets. In addition to these tools a chemical

procedure was developed to help quantify the chemical composition of the pellets.

Nitrogen Adsorption

Theory

The nitrogen inside the sample tube is able to condense on the pore surface. This

has been modeled by a number of scientists over the years. There are monolayer models

and multi- layer models. Some account for capillary effects in pores and others do not.









One of the most widely used models is the BET multilayer adsorption model which

builds upon the Langmuir monolayer model.

The Langmuir model relates the concentration of vacant sites and filled sites in

adsorption process. The model has a form similar to a kinetic rate law. For nitrogen it is:


k (k c C N2-S
AD A N2 v K
D P KA ) (4.1)

where rAD is the rate of adsorption. kAis rate coefficient for adsorption. PN2 is the pressure

of nitrogen. Cv is the concentration of vacant sites. CN2-S is the concentration of sites

which are filled by a N2 molecule. KAis the equilibrium adsorption constant. Though,

the pressure for nitrogen can be monitored all the other parameters must be known from

earlier experimentation. However, when nitrogen is adsorbing on a surface the rate is

different than if it is forming a multilayer on previously condensed nitrogen. Thus once

the total surface is covered the rate is fairly constant and can be seen as the linear middle

section in the plotted BET isotherm in Figure 4.1. The beginning of this linear region

can be used to estimate the total surface area based on the volume adsorbed.

BET Isotherm

A BET (Brunauer, Emmett, and Teller, 1938) Isotherm describes the multilayer

adsorption case for most surfaces. However, in materials with small pores this equation

becomes less accurate due to capillary forces across the pores. Thus another calculation

scheme has been developed by Barrett, Joyner, and Halenda (BJH).
















40


0 30


S20




0
0 0.2 0.4 0.6 0.8 1
P/Po



Figure 4.1 Typical BET Isotherm

BJH Pore Size Distribution

Barrett, Joyner, and Halenda (BJH) derived a relationship that can be used to

create pore volume distributions or pore area distributions over a range of pore sizes

(Barrett et al., 1951). In their derivation they used the proposed mechanism by BET for

multilayer adsorption but account for capillary condensation. There are two main

assumptions that are used in this derivation. The first is that all the pores are cylindrical.

The second is that nitrogen is adsorbed by two means being condensation on the pore

walls and capillary condensation. The derivation also uses the Kelvin equation relating

pressure, surface tension, and pore radius. This method gives results within 1 to 5% of

the BET total surface area measurement.










(P/Po)1 (P/Po)2 (P/Po)3








t t4 t2 ~-- 14 t3-
rpl rkl dt3 -rp2 --rk2- .1 -rp3 -rk3- -t4
dt2 ..11 dt3
dtl
Vpl=R1*dV1 Vp2=R2*dV2-R2*dT2*Ac1
Vpn=Rn*dVn-Rn*dtn SUMUj=1 to n] (Acj)

Figure 4.2 Schematic Representation of Assumed Desorption Mechanism
Showing Three Different Pores and Demonstrating the Thinning of the Physically
Adsorbed Layer Over the First Three Decrements (Barrett et al., 1951)

The pressure is increased gradually until the sample is saturated or has reached

the preset pressure. The pressure is then reduced stepwise so that a certain volume of

condensate is emptied from a certain pore size range; The condensate layer thickness is

reduced or the capillary condensate is emptied. A volume of gas at a given pressure is

measured. This volume can be converted to condensate volume knowing the liquid and

vapor densities of nitrogen. Thus the pore volume can be found. This is a simplified

explanation of the theory. Detailed treatment of the theory is available by Barrett,

Joyner, and Halenda (1951). Nitrogen adsorption and mercury porosimetry are also

explained clearly and compared by Westermarck. (2000)

Procedure

A Quantachrome NOVA 1200 machine located at the Particle Science

Engineering building was used for nitrogen adsorption tests. Two to three pellets are

placed in a sample cell (similar to a test tube). The cell is placed into an airtight station in

the NOVA machine. It is then vacuum outgassed for a duration which depends on the









sample. The sample is heated to 2000C during the outgassing procedure. Outgassing

elutes the moisture from the sample, making the pore surface available for nitrogen

adsorption.

At this point the mass and the density of the sample are entered in the instruments

software. The sample cell is moved to the analysis station. A dewar (container) of liquid

nitrogen is raised so that the cell is surrounded by liquid nitrogen. Starting from very low

pressures, nitrogen is incrementally added into the cell. Some of this nitrogen is adsorbed

into the pores of the sample. The pressure is increased until atmospheric pressure (770

mm Hg) is reached. The pressure is then reduced stepwise. A certain amount of

nitrogen desorbs at each pressure. This is measured through pressure reading and/or air

flow out of the cell. The amount of desorbed nitrogen can be correlated to pore size

using theory.

Mercury Porosimetry

Theory

The theory behind the mercury porosimeter is relatively simple compared to that of

Nitrogen Adsorption. Mercury porosimetry uses the capillary relationship given by

Washburn equation (Eq. 4.2) to calculate pore size based on pressure.

D= -4y cos(O)/P (4.2)

Knowing the contact angle of mercury (0=1400) and surface tension (y= 480

dyne/cm), the pore diameter can be correlated to the pressure inside the chamber.

Mercury porosimetry like nitrogen adsorption, assumes that the pores are cylindrical. It

also assumes constant mercury properties.









Procedure

The Quantachrome Autoscan 60 Mercury Porosimeter in the Particle Science

Engineering Building was used to measure the porosity of the pellets. A porous sample is

placed in a small glass container with a long thin tube at one end. The air is evacuated

from the system using a vacuum pump. Mercury is then pushed up the long thin tube

until the container and the tube are full. The mercury porosimeter works by measuring

the capacitance of the mercury in the tube. As the pressure is increased in the chamber

more mercury is pushed into the pores of the pellet. As the column of mercury is

decreased, the capacitance changes by a certain amount which is calibrated so that a

volume can be calculated. The pressure in the system is increased slowly so that more

mercury intrudes into smaller pores. Using the pressure and Washburn equation the pore

size can be calculated. Thus, a volume from the measured capacitance can be obtained

and correlated to the pore size calculated from the capacitance. The pore size

distributions are generated in this manner.

Raman Spectroscopy

Theory

Raman spectroscopy is a light scattering technique to determine the composition

of molecules. A laser is focused onto a surface. The light is then inelastically scattered

according to the bonds of the molecule. This is called the Raman effect. The Raman

effect only occurs for about 1 in 10 million incident photons and is therefore a weak

signal. Inelastic scattering occurs when a photon gains or loses energy from the vibration

energy of bonds in a molecule (Eq. 4.3). If the photon loses energy it will have a higher

wavelength than the exciting light. This is called the Stokes line and is generally what is

measured. If a photon gains energy it will have a lower wavelength than the exciting









light. This is called the anti-stokes line and is generally very week and hard to detect.

The change in wavelength of the stokes and anti-stokes line is related to the vibrational

energy spacing. Thus these changes can be used to directly measure the vibrational

energies of the molecule. In order to detect these weak signals a high powered

monochromatic light source such as a laser is used.

h/?in + Evib= h/ kut (4.3)

This scattered light is detected over a spectrum of wavelengths. The spectra for

materials are different based on their bonds. This can be seen in the spectra for different

materials. Characteristic peaks will indicate the presence of particular types of

molecules. Raman spectroscopy also has a signal in which the relative intensities of the

characteristic peaks can be correlated to the concentration of a certain substance. In order

to do this, spectrum must be taken from known concentrations of species of interest.

Procedure

A sample of powder is prepared and put into a melting point capillary tube. A

computer is attached to the Raman spectrometer. A program called OMNIC is used to

adjust the laser light so that the best signal is obtained. The laser is focused onto the

sample and the scattered light is reflected to a spectral detector. This signal can be

measured for different lengths of time. OMNIC also averages a number of signals which

can be varied. A number of other parameters affecting strength of the laser and the signal

detection can be changed. A spectrum is then obtained for each sample. Characteristic

peaks at certain wavelengths will indicate the presence of a particular substance.

Sometimes the strength of the signal can also be correlated to the concentration of the

particular substance of interest if calibrated using known concentrations.









Chemical Testing

Theory

Chemistry can be used to determine the amount of CaO present in the pellets. The

two main components in the pellets are CaO and CaTiO3. CaO reacts with HBr to form

CaBr2 yet CaTiO3 does not react with HBr or H20. The percentage of CaO can be

found using the molecular weights CaO and CaBr2 and the difference is weight after a

reaction with HBr and evaporation of volatiles.

Procedure

Samples were made of powder produced with modified chemistry and heating

procedures. Each sample was placed in a sample container and weighed. An excess

molar amount of hydrobromic acid was added to each container via a 48% by weight

solution of hydrobromic acid in water. The mixtures were then subjected to 800C heating

for 18 hours. The heating temperature was increased to 1000C for 4 hrs and to 2000C for

an additional 2 hours. All the chemicals were volatile except for the calcium compounds.

The amount of CaO can be quantified by finding the change in weight resulting from the

added HBr solution because CaTiO3 does not react with HBr. The extent of the reaction

was determined by using laboratory grade CaO and performing the same procedure. The

extent of the reaction was found to be 98%. This procedure was used to determine the

amount of CaO in each sample. An error of about 5% is estimated using this procedure.

Though, small amounts of CaCO3 and TiO2 can be present in the pellet most of it is

composed of CaO and CaTiO3. Thus, after the CaO is calculated the amount of CaTiO3

can be approximated as the remainder of the composition.














CHAPTER 5
EVALUATION OF PARAMETERS

The effect of various parameters on the pellet characteristics-the porosity, the

chemical composition, and the strength-was studied to develop the molding and heating

procedures. The parameters are listed in Table 5.1 and are associated with the chemical

formulation, molding procedure, and pellet heat treatment. Correlations have been made

between procedural parameters and the resultant characteristics of the pellet. The

optimum procedure has been chosen based on these correlations. These correlations and

the optimum procedure parameters are presented in this chapter.

Correlations from Original Chemistry

The original chemistry was helpful for determining a general range of parameters

for the heating procedures and molding procedures. However, this procedure had to be

modified to attain the desired composition in the pellets. Figure 5.1 is a diagram that

illustrates how the parameters were evaluated based on the resulting characteristics.

Within each of these general categories describing the procedure there are parameters

which can be seen in Table 5.1. The parameters with a (1) are ones which were varied to

characterize the pellets using the original chemistry. Likewise, a (2) indicates parameters

for the modified chemistry. An (M) indicates the parameters which were changed as a

direct result of feedback from the characteristics of the resulting pellets. Parameters

without any of these designations were established in the original procedure and not

significantly changed or varied to investigate how the characteristics of the pellet

changed.









Table 5.1 Parameters in the Main Categories Shown in Figure 5.1
Chemistry (M) Molding Heating Procedures
Ca/Ti Ratio (2)(M) Compression Force (1) (M) Drying Time & Temp.
pH Binder Additive (1) Preheating Time & Temp (M)
Water/Ca (M) Max Sintering Time & Temp.(1) (2)
Ethanol/Ca (M) Temp. Ramping Scheme (M)
CondensationTime and Temp.


Figure 5.1 Flow Diagram Indicating How Characteristics Were Used as Feedback to
Modify the Parameters to Arrive at the Final Procedures

Molding Procedure: Strength

The strength was qualitatively be analyzed. If the extruded pellet fell apart it was

deemed too weak. Most of the pellets formulated using the original chemistry required a

compression of 1.0 metric ton to ensure whole pellets.

Heating Procedure: Strength and Microporosity

The heating procedures were evaluated based on the strength and the microporosity

of the pellet after heat treatment. The preheating step was added to improve strength as

described in chapter 3. The merits of the heating procedures were also evaluated based










on the strength of the pellets after heating. The pellets remained intact with no significant

cracking during heating. Higher temperatures led to sintering and created stronger

pellets. This was qualitative comparison as no quantitative strength test has been done.

The maximum temperature of the heating had a direct impact on the microporosity

of the samples. The cumulative pore volume was measured using nitrogen adsorption in

conjunction with a BJH correlation and is plotted against the maximum sintering

temperature in Figure 5.2. The data fit a correlation y=0.0012x2-2.6701x+1433.7 where

x is the maximum sintering temperature and y is the cumulative pore volume. The

microporosity decreased drastically from maximum temperatures between 7000C and

10000C for pellets with the same chemistry and molding procedures. At 7000C the

porosity is 0.171 cc/g which drops down to 0.006 cc/g when the sintering temperature is

increased to 10000C. The intermediate temperatures of 8000C and 9000C show the

decreasing trend. A sintering temperature of 8000C was chosen for investigation with the

pellets created using the new chemistry. This temperature gave a reasonable strength to

the pellets without drastic loss in porosity.



200
S180
160
I 140
S120

0 100 y = 0.0012x 2.6701x + 1433.7
80
i60
S40
20
0
700 750 800 850 900 950 1000 1050
Max Heating Temp [C]


Figure 5.2 Specific Cumulative Micropore Volume vs. Maximum Sintering Temperature










Chemistry: Chemical Composition

Raman Spectroscopy identified the composition of the first pellets. Two pellets

were tested and found to closely resemble the Raman spectra for rutile and anatase-TiO2.

This confirmed suspicions that the original chemistry did not form the desired network.

Figure 5.3 shows the Raman spectra from two pellets made using the original chemistry

along with the spectra for both anatase and rutile TiO2 where the y-axis is the intensity

(Int) of light for that wavelength. Pellet 1 appears to be mostly anatase TiO2. Four

matching anatase peaks can be seen from left to right. However, there are no rutile

peaks. The spectra for the second pellet has peaks of both anatase and rutile TiO2

indicating the presence of both phases of TiO2 in the pellet. This probably occurred due

to the different heating procedures this pellet underwent. Peaks for CaO and CaTiO3 are

markedly absent in these spectra. Because of the minute amount of CaO the original

chemical procedures had to be modified.






o-o




2J-









600 500 400 300 200
Raman shift (cm-1)

Figure 5.3 Raman Shift Spectra of Anatase and Rutile TiO2 and Two Representative
Pellets Made Using the Original Chemistry









Correlations from Modified Chemistry

Correlations were made between the characteristics of the new pellets (made

using the modified chemistry) and the procedural parameters. Figure 5.4 illustrates how

the characteristics are used to evaluate the parameters in this modified procedure. Refer

to Table 5.1 for parameters within each main procedural step.



Modified Chemistry Pellet Molding Procedure



Strength Strength

Pellet Heating Procedure


Strength, Macroporosity, Composition Strength, Macroporosity

Final Molding,
Heating, and
Chemical Procedures


Figure 5.4 Visual Flow Diagram of How Characteristics were Used as Feedback to
Modify the Parameters Using the Modified Chemistry

Molding Procedure: Strength and Macroporosity

The new pellets required a compression force of only 0.25 metric tons to hold

together as compared to 1 metric ton for the previous pellets. This improvement is

considerable because increased strength at lower compression will result in greater

porosity for these pellets.







74



A comparison between new pellets compressed at 0.5 metric tons and 0.25 metric


tons was conducted. The pellets were made with a 2 to 1 ratio between calcium and


titanium and heated to 8000C using the same heating scheme. The size of the pores


seems to remain in the same range indicated by the differential distribution which peaks


around 100nm. However, the specific cumulative pore volume for the pellets was


approximately 0.15cc/g less at the 0.5 metric ton compression. This is shown in Figure


5.5 by the smooth curves increasing right to left to a maximum at 10 nm. For reference a


larger version of this graph can be found in Appendix F, (Figure F.2).


Cumulative and Differential Pore Volume Distributions
07 -0006


06
-0005




03
0. 002












10 100 1000
Pore Diameter [nm]
03 \ '" AA b










0 5MT Cumulative 0 25MT Cumulative 0 5MT Differential
10 0002








0 5MTCumulative -0 25MTCumulative A 0 5MT Differential
025MT Dfferential 10 per Mov Avg (0 5MTDifferential) 10 per Mov Avg (0 25MT Differential)



Figure 5.5 Comparison of Cumulative and Differential Specific Pore Volume
Distribution for New Pellets Compressed at 0.25 and 0.5 Metric Tons.


Chemistry: Macroporosity, Microporosity, Composition, and strength

Using the modified chemistry a network of CaO and CaTiO3 was synthesized.


An attempt was made to use Raman Spectroscopy to verify the existence of CaTiO3 and









CaO. At first the sample spectra obtained were inconclusive as their peaks did not match

either those of the pure CaO spectrum or CaTiO3 spectrum as expected. One possible

reason for this may be electrical interaction that may occur in the samples. Since the scale

of mixing using the alkoxide chemistry is at the molecular level, which may alter the

electronic response. This would affect the Raman spectroscopy as it uses light scattering

that can be affected by slight variations in the electric fields of the samples. Appendix E

(Figure E.2) shows the comparison of a sample made using the modified chemistry, Pure

CaO and Pure CaTiO3. The samples were also compared to spectra from CaCO3,

Ca(OH)2, TiO2-rutile, and TiO2-anatase to identify if any of these substances was present.

There did not appear to be any strong matches in the samples formulated with the new

chemistry and these compounds. One sample did have a small matching peak with

CaCO3 indicating a small percentage of CaCO3 (-2-5%). The florescence of the samples

generate broad peaks which hide the species identifying peaks.

A second attempt to use the Raman spectroscopy revealed strong matching peaks

for CaTiO3 for two different pellet powders. These powders were made using a 2 to 1

ratio between calcium and titanium and heated to 10000C. The only difference between

the two pellets was the temperature of preheating. Pellet 1 was preheated at 4300C

whereas pellet 2 was preheated at 6000C. Figure 5.6 shows the matching of the peaks.

More Raman shift spectra are presented in appendix E including the full spectra of the

piece shown in Figure 5.6. It should also be noted that for this spectra the intensity value

(Int) is meaningless as the spectra were offset and scaled differently to show matching

peaks. There were no strong peaks in the spectra matching CaO, but a non-fluorescing

spectrum for CaO could not be obtained.







76


45-

z 11


















600 500 400 300 200
Raman shift (cm-1)

Figure 5.6 Raman Shift Spectra for CaTiO3 and Two Sample Pellets

The existence of CaO and CaTiO3 in a sample made from the modified chemistry

was verified through X-ray diffraction (XRD) because of the inconclusive data from the

first try at Raman Spectroscopy. The signature peaks of CaTiO3 and CaO have been

identified in the XRD taken for this sample (Figure 5.7). In addition to the XRD

verification, the amounts of CaO in the pellets were found using the chemical testing

procedure described at the end of chapter 4. Results from the chemical testing procedure

can be seen in Table 5.2 for many different samples.

In Table 5.2 the values for the %CaO are calculated based on the assumption that

calcium only exists as CaO and neglects the possibility ofCaCO3 or Ca(OH)2. The

assumption is poor at low temperatures. The existence of CaCO3 and Ca(OH)2 is evident

in the high percent error in the Modified Chemistry Powder 2 data for the unheated and

4300C heated runs. However, this seems to be a reasonable assumption when the










maximum heating temperatures is 10000C. The temperature drives the dissociation of

any Ca(OH)2 or CaCO3 that may be present. Thus, the results show that the presence of

CaO is close to the expected percentage based on the stoichiometric relationships

between calcium and titanium.

The standard samples of CaO and CaTiO3 justify the validity of the test. CaO and

CaTiO3 are within 2% and 3% of their theoretical values respectively. The CaTiO3 in

the pellet powder can also be seen unreacted at the bottom of the sample container. One

other point of interest is that the samples made with powder from the original chemistry

do not indicate any appreciable reaction. This again confirms the minute amount of Ca in

these pellets.

Table 5.2 Results of Quantitative Chemical Composition Testing Procedures
Experimental Parameters %CaO
Sample Description Ca/Ti Max Heating Temp Exp. Theor. %Error
Mod. Chem. Powder 1 1 430C 9.0% 0.0% 9.0%
Mod. Chem. Powder 1 1 430C 8.7% 0.0% 8.7%
Mod. Chem. Powder 2 2 1000C 45.4% 50.0% 9.2%
Mod. Chem. Powder 2 2 430C 25.5% 50.0% 49.1%
Mod. Chem. Powder 2 2 unheated 30.7% 50.0% 38.6%
Mod. Chem. Powder 3 2 1000C 47.1% 50.0% 5.8%
Mod. Chem. Powder 4 3 1000C 58.7% 66.7% 12.0%
Original Chem. Powder 1 ~0 900C 0.6% 0.0% 0.6%
Original Chem. Powder 2 ~0 1000C 0.3% 0.0% 0.3%
Pure CaO N/A none 98.3% 100.0% 1.7%
Pure CaO N/A none 98.0% 100.0% 2.0%
Pure CaTiO3 1 none 3.3% 0.0% 3.3%

The ratios of calcium to titanium in the chemical formulation were varied to

determine its affect on the strength, composition, macroporosity and microporosity. Both

the macroporosity and microporosity decreased with an increase in the calcium to

titanium ratio. These pore volumes are compared to those reported by Sakurai et al.

(1995) in Figure 5.8. In order to have a direct comparison the pore volume was

normalized by the volume of the respective pellets. Spheres of 5mm diameter were used












for Sakurai et al. because that was recorded in their papers and cylinders of 3/16"


diameter and 5/16" length were used for this work. Note that the microporosity in the


new pellets is greater than those reported by Sakurai et al. The macroporosity for the


new pellets however is less. This is a little misleading in that much of the porosity


recorded in the micropores was very close to the transition between micro and macro


pores at 0.1 to 0.2 microns. This can be seen in the differential and cumulative


distributions for these ratios in Appendix F, Figure F.1. These pores can be manipulated


by changing some of the procedural parameters to yield more macropores. Graphite


which was not introduced in our pellets will also help to increase the porosity in the


macropore region and micropore region.




counts/s

Ca 103
250

CaO
CaT103

200-


CaO CaTlO3
150-



CaT103
100-
CaO

CaO
5 T1033 CaT 03 CaTiC C





0T
20 30 40 50 60 70 80
2Theta


Figure 5.7 X-ray Diffraction Data with Peaks Verifying the Presence of Both Calcium
Oxide and Calcium Titanate











0.8


0.7


0.6


0.5


0.4

0.3



0.2


0 .1 .-.-.-.-.-.-.-.
0.1



c<.5um (Ca2/Til) B<.5um(Ca3/Til) H<.5um (Ca4/Til) E <.5um UT-3
S>.5um (Ca2/Til) D>.5um(Ca3/Til) M>.5um (Ca4/Til) >.5um UT-3


Figure 5.8 Comparison of Micropore and Macropore Volume of Pellets Made with Ratios
of Different Calcium to Titanium Ratios with UT-3 (Sakurai et al., 1995) Porosity
Results


The strength of the pellets generally decreased with an increase in the calcium to

titanium ratio. The pellets seemed to be more fragile and had more cracks for a ratio of 3


and 4 (Ca:Ti, molar). This was expected because a greater ratio decreases the percentage

of titanium which is the element which forms the substrate structure. When the percent of


titanium is decreased it is, therefore, expected that the integrity will also decrease.


Heating Procedures: Composition, Strength, and Porosity

The heating procedures were evaluated based on the characteristics of


composition, strength, and macroporosity. A comparison of the porosities can be seen in


Figure 5.9 (Enlarged as Figure F.3). The cumulative and differential specific pore

volumes are shown. The differential distribution seems to be flatter when 9000C and









10000C heating temperature were used. This indicates that the pore volume is distributed

amongst a greater range of pore sizes. The 8000C heated pellets had a much narrower

pore volume distribution. The pore volume was highest in 8000C heated pellet.

However, the maximum difference in the cumulative pore volume, is only about 0.05

cc/g between the 8000C and 9000C heated pellets. These pellets used a 2 to 1 ratio

between calcium and titanium and were compressed into pellets using a 0.25 metric tons

force. All the pellets were also preheated at 4300C.

The 9000C and 10000C pellets were actually weaker than the 8000C pellet in this

case. The reason for this is believed to be Ca(OH)2 and/or CaCO3 dissociating at their

dissociating temperatures of 5800C and 8980C respectively.. Two slight modifications to

the heating process were made.

1. The preheat temperature was raised to 6000C to eliminate any calcium hydroxide
that might be in the pellet.

2. The ramp time from 7000C to the maximum sintering temperature was extended
to 2 hours to slow the formation and escape of carbon dioxide as calcium
carbonate dissociates.


The pellets made using these modifications seemed to be just as strong if not

stronger than the 8000C heated pellets. The composition of the pellets was quantitatively

measured using chemistry by the procedure outlined at the end of chapter 4. Table 5.2

Shows values for different ratios and heating schemes

Optimum Parameters

There are many parameters which can effect the characteristics of the pellets. The

most important characteristics-reactivity and degradation-have yet to be studied.

What may seem the optimum based on the characteristics of strength, porosity, and

composition may not even last one cycle in a reactor. Even with just the characteristics







81



explored in this work it is difficult to weight each characteristic as they are


interdependent. With these considerations Table 5.3 presents what are thought to be the


optimum of the varied parameters based on the data collected.


0007


0006


0005 8
E
0004 0


0003 .
()

0002


0001


100 1000
Pore Diameter [nm]


-- 800C Differential 1000C Cumulative
900C Cumulative 800C Cumulative
1000C Differential 900C Differential
10 per. Mov. Avg. (800C Cumulative) 10 per. Mov. Avg. (1000C Differential)
10 per. Mov. Avg. (900C Differential )


Figure 5.9 Comparison of Cumulative and Differential Specific Pore Volume
Distribution for New Pellets Sintered at Different Temperatures.


Table 5.3 Optimum Parameters
Use Modified Chemistry Scheme 2Ca:1Ti
Precursor Preheating Temp. 600C
Molding Compression Force 0.25 MT
Sintering Temperature 900C
Slow Temp. Ramping Scheme 2hrs


The modified chemistry is used to create the pellets. A 2 tol ratio between


calcium and titanium was chosen. This was in large part to ensure that adequate CaTiO3


network is generated to make the pellets structure strong to endure the reactor


environment. The preheating temperature was to eliminate volatiles that may affect the









strength when the pellet is heat treated. The compression force was picked because it is

thought that it would help the porosity and give an acceptable strength. The 9000C

sintering was chosen because it strengthens the pellet but does not decrease the porosity

greatly. It is also thought that this would dissociate any CaCO3 so that the CaO content

would be increased.

This work has focused on cylindrical pellets, though there are many different

shapes and sizes of pellets that are used in industry. The question has been raised, "Can

these characteristics be maintained if a different pellet shape or size is used?" This

question can not be answered simply. Some characteristics will always be maintained

while others will vary slightly depending on the pellet making procedure. The

composition for example will always remain the same if the same chemistry and heating

procedures are used. The strength and porosity, however, may change in different pellet

shapes and sizes. The consolidation force used to compress the pellets will greatly affect

the macroporosity and the strength as shown earlier in this chapter. The shape could also

contribute to the macroporosity. Generally, macropores are found closer to the surface of

the pellets. This means that the shapes with a larger surface area to volume ratio you

would expect to have greater macroporosity per unit volume. The size of the pellet also

makes a difference in the porosity. Pore clogging and sintering occur in the pellets

because of the procedural steps. Because of this less pores are accessible further into the

pellet. Thus, if pellets with the same surface area to volume ratios and different volumes

are compared the one with the smaller volume will yield a higher specific pore volume.

The strength of the pellets obviously can depend on shape. For instance an annular pellet

will probably not be as strong as a cylindrical one. There are many established






83


techniques for creating these pellets and the only true way to see the effect of a new

shape and/or molding procedure on the characteristics is to study them.