4生物质能工程(4)

AdvancedBioethanolTechnologyBiofuelsresearchershelpleadanationalefforttodeveloplignocellulosic(木素磺化盐)biomass-to-ethanoltechnologiestotaptheenormousenergypotentialofbiomassforthetransportationsector.Researchanddevelopmentactivitiesarebeingcarriedoutonfourbioethanoltechnologyplatformsincollaborationwithindustryanduniversities.•Therearefourbasicstepsinconvertingbiomasstobioethanolfourbasicstepsinconvertingbiomasstobioethanol•Producingbiomassresultsinthefixingofatmosphericcarbondioxideintoorganiccarbon.•Convertingthisbiomasstoauseablefermentationfeedstock(typicallysomeformofsugar)canbeachievedusingavarietyofdifferentprocesstechnologies.Theseprocessesforfermentationfeedstockproductionconstitutethecriticaldifferencesamongallofthebioethanoltechnologyoptions.fourbasicstepsinconvertingbiomasstobioethanol•Fermentingthebiomassintermediatesusingbiocatalysts(microorganismsincludingyeast酵母(菌)andbacteria)toproduceethanolinarelativelydiluteaqueoussolutionisprobablytheoldestformofbiotechnologydevelopedbyhumankind.•Processingthefermentationproductyieldsfuel-gradeethanolandbyproductsthatcanbeusedtoproduceotherfuels,chemicals,heatand/orelectricity.GeneralschemeforconvertingbiomasstoethanolFourTechnologyPlatforms•TheBioethanolProjectsupportsdevelopmentoffourtechnologyplatformsforbioethanolproduction.Thefirstthreearebasedondifferentapproachestoproducingsugarsfrombiomassandthenfermentingthesugarstoethanol.Thefourthisaverydifferentapproachinvolvingthermalprocessingofbiomasstogaseoushydrogenandcarbonmonoxide,followedbyfermentationtoethanol.•ConcentratedAcidHydrolysis•DiluteAcidHydrolysis（水解）•EnzymaticHydrolysisBiomassGasificationandFermentationResearchandDevelopmentActivities•BioethanolProjectresearcherscollaboratewithindustryanduniversitiestodevelopandfacilitatecommercializationofbioethanoltechnologyintheUnitedStates.BioethanolTechnologyProcessEngineeringandAnalysis•Processengineeringandanalysisofbioethanoltechnologiesiscarriedouttosupportresearch,developmentanddemonstrationprojectstoconvertcellulosic（纤维质的）biomasstoethanol.Activitiesincludedevelopingconceptualprocessdesigns,conductingtechnicalandeconomicevaluations,evaluatingresearchanddevelopmentalresults,identifyingareasforfutureresearchanddevelopment,andsupportingengineeringdesignsfordemonstrationplants.Thisongoingeffortcombinestheresourcesoffederal,institutionalandprivategroupstohelpstreamlinethebioethanolresearcheffort.CurrentResearch•Twonewdesignreportstobepublishedin2002willdetailthedesignbasisandeconomicparametersfortheenzymatichydrolysisprocessandthetwo-stagediluteacidhydrolysisprocess.ThereporttitledLignocellulosicBiomasstoEthanolProcessDesignandEconomicsUtilizingCo-CurrentDiluteAcidPrehydrolysisandEnzymaticHydrolysiswillprovideacompleteupdateddesignbasisfortheenzymebasedprocesswithadetaileddiscussionofalldesignassumptionsandeconomicevaluationparametersincludingequipmentsizeandcostsandprojectionsofethanolproductioncostsfortheyear2010.•Alternately,theLignocellulosicBiomasstoEthanolProcessDesignandEconomicsUtilizingTwo-StageDiluteAcidHydrolysisreportcontainsacompletedesignbasisforthetwo-stagediluteacidhydrolysisprocesswithadetaileddiscussionofalldesignassumptionsandeconomicevaluationparametersincludingequipmentsizeandcostsandprojectionsofethanolproductioncosts.•Inanefforttoimprovetheprocessdesignandstrengthentheinformationitisbasedon,theprocessengineeringgroupisalwaysworkingwithacollectionofengineeringfirms,otherfederalagenciesandoperatingcompanies.Thesecollaborationsprovidevaluableinsightforcreatingasoundprocessbasedonindustrystandardsandengineeringprinciples.BiofuelsandtheEconomy•TheU.Seconomyissocloselytiedwithpetroleumproductsandwithimportsofcrudeoilthatsmallchangesinthepriceofcrudeoilordisruptionstooilsuppliescanhaveanenormousimpactonoureconomy,fromtradedeficits,toindustrialinvestment,toemploymentlevels.Todayoilimportsaccountforalmostone-thirdoftheU.S.tradedeficit.Inadditiontohurtingtheeconomy,thehightradeimbalancefromdependenceonforeignoilalsoleavesoureconomyvulnerabletopricehikesfromsupplydisruptions.DevelopingastrongbiofuelsindustryintheUnitedStateswillhavetremendouseconomicbenefitsincludingtradedeficitreduction,jobcreation,andstrengtheningofagriculturalmarkets.•Currently,theethanolindustryisresponsibleforapproximately200,000jobs.Ethanolproductioncreatesdomesticjobsinplantconstruction,plantoperation,plantmaintenance,andplantsupportinthecommunitieswhereitisproduced.ThishasaprofoundimpactonruralAmericawhereadeclineinemploymenthasplacedincreasingburdensonourcities,infrastructure,andtaxbase.ThehigherlevelofeconomicactivitycreatedbytheethanolindustryincreasesFederaltaxreceiptsby$3.6billionannually.BiofuelsandtheEnvironment•Transportationisamajorcauseofadverseenvironmentalimpacts.Muchofthistransportation-causedenvironmentaldamagecanbesubstantiallyalleviatedbysubstitutingbiofuelsforfossilfuelsorjustbyusingthemasfueladditives.FromcarbonmonoxideandozoneairpollutiontoMTBEcontaminationofgroundwatertoglobalwarming,usingbiofuelscanhelp.AirPollution•Thetransportationsectorisresp