ChemicalChallengesinRenewableenergy在可再生能源化工的挑戰(zhàn)

ChemicalChallengesinRenewableenergy在可再生能源化工的挑戰(zhàn)第1頁/共30頁Thanitappearsthatrenewableresourceswillnotplayalargeroleinprimarypowergenerationunless,oruntil:.Costbreakthroughsincarbon-freetechnologiesareachieved..Externalitiesareintroduced,suchasenvironmentallydrivencarbontaxes.

Actuallyalsoiftherearereassuringresourcesoffossilfuels,geopoliticalandregionalfactorscanaffectsignificantlythepriceofenergy.

Canwesupplytheenergyneededinthefuturewithfossilfuel?Quiteprobableyes.第2頁/共30頁Currentglobalenergyconsumption=13.8TWBy2050consumption=25TW.Needabot10TW.Fossilfuels:Canproduceextra10TWonlyatrisktoenvironment.Wind/Geothermal/Biomass/Hydroelectric:Cannotproduce10TW.(Butshouldbeimplementedwhereappropriate:energyisextensive)Nuclear:Requiresmassiveinvestmenttodaytoprovidepowerplantinfrastructure(10TW=10,000new1GWreactors,in50years).第3頁/共30頁TheemploymentofgeologicalreservoirsispotentiallyfeasiblebutitarisesproblemsformaintainingalowrateofofCO2leaking.Besidesforthecostofplantsandinfrastructuresanincreaseofexpencesof15%ispredicted.Inconclusionitappearstobeapromisingoptionwithuncertaintiesinhis:technicalandeconomical

ASPECTS.Carbondioxidesequestration第4頁/共30頁

RenewableThetotalrate(TW)issharedbetweendifferentcategories:-hydroelectric0.3pv=1.5-geothermal0.03pv=12-eolic0.074pv=7-biomass1.3(+)-solar0.03pv=600(+)duetothelowefficiencyofphotosynthesisabout17%oftheoftheterrestrialarealandisrequiredtoproduce10TW.第5頁/共30頁LightFuelElectricityPhotosynthesisFuels

ElectricityPhotovoltaicsHOOH222scMesceMCOSugarHOO222Semiconductor/LiquidJunctions

conversionstrategiesSolarenergyappearstobetheonlysourceabletosupply10-20TWcarbon-freepowerneededat2050.第6頁/共30頁Whatistheareaneededtogeneratetherequiredpower?Thefullenergyconsumedintheworldcanbeproducedinatropicallandwithasquaredareawithasideof500Km.ThepresentenergyemployedinItalycanbeproducedinalandareawithasideof60KmItissufficienttocoverabout0.17%oftheterritory.第7頁/共30頁

SolarisexpensiveTypicallevelizedcostbysourceSolar’stypicalrangeof25-50cents/kWhismuchhigherthanothersources第8頁/共30頁

ItcompeteswithgridpricenotgeneratorcostAverageresidentialgridprice(UScents/kWh)Mucheasiertocompetewithgridpricethangenerationcost.第9頁/共30頁Silicontechnologydominatesthemarket:93%forcrystallineSi(single-,multi-,poly-,nano-)MarketshareforSiandthinfilmtechnologieswerecontinuouslydecreasingduringlast10yearsMarketsharebytechnology10Pricesandpredictionsofphotovoltaicmarket第10頁/共30頁ModuleefficiencyLabscaleMaxefficiencyHITheterojunctionintrinsicthinfilmManydifferenttechnologiesonthemarketrushingforhighefficiency&lowcosts第11頁/共30頁Shockley-Queisseranalysis(1961)Itisbasedonfourassumptions:1-singlep-njunction2-oneelectron-holepairexcitedforincomingphoton3-thermalrelaxationoftheelectron-holepairenergyinexcessofthebandgap4-illuminationwithunconcentratedsunlightMaximumyieldof31%isobtained.第12頁/共30頁S-Qlimitcanbeexceededbyviolatingoneormoreofitspremises.A-Intermediate-bandsolarcellsB-Quantum-wellsolarcellslC-MultiplejunctionscellsC第13頁/共30頁EmploymentoforganicmaterialsLUMO=LowestUnoccupiedMolecularOrbitalHOMO=HighestOccupiedMolecularOrbital

XSC:ExcitonSolarCells

UnsaturatedMolecolesandfullerenesfor:-harvestingsolarradiations-togiverisetoafastchargetransfer-tolimitthereturntothegroundstate第14頁/共30頁PlasticCells:Scale-upusingRoll-to-RollTechniquesPrintedorcoatedinexpensivelyonflexiblematerialsusingroll-to-rollmanufacturingCanbeproducedwithvaryingdegreesoftranslucencysothatitiscustomizedforspecificmarketsEnvironmentallyfriendlyEasilyscaledupUtilizeswidespectrumoflight16第15頁/共30頁Solarelectricitycostasafunctionofmoduleefficiency.I-Wafersofsilicon.II-Thinfilmsofamorphoussilicon,tellurides,selenidesIII-Researchgoals:carriermultiplication,multiplejunctions,sunlightconcentration,newmaterials(organic).第16頁/共30頁SiliconSi

Eg

=1,1eVGalliumArsenideAgAs

Eg=1,5eVTitaniumDioxideTiO2

Eg=3,2eVTiO2fulfilstherequirementbutitabsorbsonlytheultravioletradiation,thatisonly3%oftheavailablesolarenergy.SCsemiconductor(photocatode)Mmetal(anode)Waterphotodissociationoccursifhν>2.97eVPhotoelectrochemistry(Photo)chemicalWaterSplitting:

2H2O→O2+2H++2e-+H2第17頁/共30頁Operationprinciplesofadye-sensitizedmesoporousheterojunctionsolarcell.(Gratzel)Graydots:mesoscopicoxideparticlescoveredwithamonolayerofdye.第18頁/共30頁Thedevelopmentofenergetictechnologiesarisesnewandstimulatingchallengesforchemicalsciences:-Complexsystemsincludingmanydegreesoffreedom

.Whatistherealcostofthesiliconsolarenergy?.Howimportantwilltheburningofcoalbetoglobalwarming?-Chemistryofsmallmolecules,impliedin:.Atmosphericchemistry.Combustion.Newfuelsynthesis..Excitactionandtransferofelectrons.-ChemistryofCO2involving:.Newapplicationsonlargescaleprocesses第19頁/共30頁Designofnewcatalyticsystems,involvedinenergyproduction,suchas..Activationofmethanetomethanol

CH4+(1/2)O2→CH3OH.PhotoreductionofCO2tomethanolCO2+6H++6e-→CH3OH

.Improvementoftheslowcatodicprocessesreactions.FuelcellsoperatingwithmetanolCH3OH+H2O→CO2+6H++6e-

第20頁/共30頁“Gastoliquids”HydrogenMethanolSyncrudeOlefinsChemicalsDimethhyether(DME)FuelsNaphtaDieselJetFuelLubricantsAmmoniaRefineryproducts“Gastohydrogen”“Gastochemicals”CO+2H2(Synthesisgas)MethaneCH4ExistingroutesviasyngasProspectivedirectroutesbeingresearchedThediscoverofnewcatalyticsystemsopensimportantperspectiveinthesynthesisofnewfuels.Asecureenergyfuturedependsonwetherchemistswilldiscoverefficientcatalystsfortheproductionofalternativefuels.第21頁/共30頁Photosyntesishasimmenseappealfortheclosedcyclecaptureofenergyfromthesun.Theprospectofnonbiologicalphotosyntesis,thatisthroughbio-inspiredchemicalreactions,deservesnewresearch.PhotosynthesisTwomassiveproteincomplexessplitwaterandcarbondioxideandforgenewenergy-storingbondsinsugarmolecules.第22頁/共30頁Howtodesignphotosynteticsystemswithartificialreactioncenters?Biominspiredapproach(BP)ChemicalAntennaforharvestingsolarenergyChemicalStructureabletotransfertheexcitedelectronatfastspeed.(0,1-1ns)ETphotosyntesisBPinterfacesGas-solid(PV)Liquid-solidRelevanceofelectrontransferprocessesET第23頁/共30頁Interdisciplinaryapproachincludingphysics,chemistry,biologyandengineering,aimedtodesignandbuildsimplifiedbiologicalcatalyticsystemswithhighefficiency.Innaturethemetabolicpathwaysareconnectedincomplicatednetworksthathaveevolvedfororganismssurvivalandreproductionandnotforfuelproduction.Therelevantstepsmightbeisolatedandconnecteddirectlytoproducefuelssuchashydrogen,methaneandalcohols.Postpetroleumeconomy.SynteticBiology第24頁/共30頁CraigVenter:Scienceonline,july2007Thegenomeofonebacteriumhasbeensuccesfullyreplacedwiththatofadifferentbacterium.Thensyntheticbiologyseemstomakepossiblenewcellfunctionsbyfusingexistinggenomes.Falloutonenergyproblems:Todevelopananaerobicspeciesthatwilldigestcelluloseintoethanol,thusgeneratingafuelfrombiomass.第25頁/共30頁Fromtheanalysisofthecarbonfreeoptionsitcomesoutthat:FossilfuelsarepenalizedbycarbondioxidesequestrationNuclearfissionrequireshighinvestimentsandneverthelessitdoesnotyetrepresentanalternativetofossilfuels,unlessnewtechnologicalbreakthroghwillemergeEolic,geothermicandbiomassenergiescanonlygiveanintegratingsupporttoth