汽车专业毕业设计翻译p001360

INTRODUCTIONMostoftheoildailyextractedisconsumedintransportation(approximately66.6%inAmerica)/publications/national_transportation_statistics/html/table_04_03.html.Oftheenergyusedinthissector,approximately65%isconsumedby\o"Gasoline"gasoline-poweredvehicles.\o"Diesel"Diesel-poweredtransport(trains,merchantships,heavytrucks,etc.)consumesabout20%,andairtrafficconsumesmostoftheremaining15%USDept.ofEnergy,"\o"/oiaf/aeo/pdf/appendixes.pdf"AnnualEnergyOutlook"(February2006),TableA2.InItaly,civilmobilityaccountsforabout74%oftotalconsumption,halfofwhichcorrespondingtoabout30%ofthenationaltotalconsumptionontransportation,insideurbanandsuburbanzones.Intheseenvironmenttherefore,caremissionsrepresentsthemainpollutionsource.Hydrogencars,byeliminatingCO2emissions,coulddrasticallyreduceinshorttimespollution,especiallyinourlivingareas.Themainobstacle,hinderingtheintroductionintothemarketofhydrogencars,isrepresentedbythelowefficiencyofhydrogenstoragesystem./publications/national_transportation_statistics/html/table_04_03.htmlUSDept.ofEnergy,"\o"/oiaf/aeo/pdf/appendixes.pdf"AnnualEnergyOutlook"(February2006),TableA2Figure1.Energydensity,bothvolumetricandgravimetric,ofvarioussystemsforhydrogenstorage.The2010and2015DOEtargetscorrespondto6.0and9.0%wt.Wecanassumethatafuelcellequippedcarwouldrunabout100kmperkgofhydrogenburned.Consequentlyastandardof400kmwouldbefulfilledby4kgofhydrogen.Fig.1showsvariousstoragesystemsdimensionedAmongthedifferentstoragesystems,thehydrolysisofhydrideseemsthebestpromisingone(Fig.2).Thereactioncanberepresentedas:2MeHn+nH2O→Me2On+2nH2 (1)Thehydrideshouldnecessarilyberegeneratedoff-board.AmongthedifferentmetalhydrideNaBH4showsahydrogencontenthigherthan10%wt.Thehighhydrogencontentandthesimplicityofsynthesismakesthesaltaperfectcandidatetostorehydrogenformobileapplication.AsafuelNaBH4islessflammableandlessvolatilethan\o"Petrol"gasoline.Itisrelativelyenvironmentallyfriendlybecauseitwillquicklydegradeintoinertsaltswhenreleasedintotheenvironment.Figure2.Weightpercentofhydrogenevolvedfromhydrolysisofvariouscomplexmetalhydrides.Thehydrogenweightwasreferredonlytotheweightofthemetalhydrideanditdoesnottakeintoaccounttheweightofwaterusedforthehydrolysis.Thehydrogenisgeneratedby\o"Catalyst"catalytichydrolysisofborohydride:NaBH4+2H2O→NaBO2+4H2 (2)Thesodiumboratecanbereverselyturnedintosodiumborohydridebywellknowmethods.Theweightpercentageofhydrogenoverthehydrideofthehydrolysisreactionisincrediblyhigh,20%.Thecompoundwasdiscoveredinthe1940'sbyH.I.Schlessinger,wholedateamthatdevelopedmetalborohydridesforwartimeapplicationsH.I.Schlesinger,H.C.\o"HerbertC.Brown"Brown,B.Abraham,A.C.Bond,N.Davidson,A.E.Finholt,J.R.Gilbreath,H.Hoekstra,L.Horvitz,E.K.Hyde,J.J.Katz,J.Knight,R.A.Lad,D.L.Mayfield,L.Rapp,D.M.Ritter,A.M.Schwartz,I.Sheft,L.D.Tuck,A.O.Walker,“Newdevelopmentsinthechemistryofdiboraneandtheborohydrides.Generalsummary”\o"JournaloftheAmericanChemicalSociety"JournaloftheAmericanChemicalSociety1953,volume75,pages186-90.In1939AntonB.H.BurgandH.C.BrownbecameresearchassistantstoProfessorSchlesinger.IntheFallof1940hewasrequestedtoundertakefortheNationalDefenseResearchCommitteeasearchfornewvolatilecompoundsofuraniumoflowmolecularweight.,withoutthecorrosivepropertiesofuraniumhexafluoride.ByusingdiboranethesynthesisofU(BH4)4,acompoundwithadequatevolatility,wassuccessful.Toeffectivelyconfirmtheresulttheywererequestedtosupplyrelativelylargeamountsofthematerial.Thebottle-neckwasthepreparationofdiborane.Bythistimetheywouldnotbeabletosupplysufficientdiboranesotheyattemptedtofindamorepracticalroute.Theydiscoveredthatthereactionoflithiumhydridewithborontrifluorideinethylethersolutionprovidedsucharoute.Unfortunately,lithiumhydridewasinveryshortsupplyandcouldnotbesparedforthissynthesis.Instead,therewasalargeamountofsodiumhydride.Unfortunately,withthesolventsthenavailable,thedirectuseofsodiumhydridewasnotsuccessful.However,anewcompound,sodiumtrimethoxyborohydrideH.C.Brown,H.I.Schlesinger,I.,Sheft,D.M.Ritter,J.Am.Chem.Soc.75,192(1953).,readilysynthesizedfromsodiumhydrideandmethylborate,solvedtheproblem.Itprovedtobeveryactivetoandprovidedthedesiredtransformationspreviouslyachievedwithlithiumhydride.Thyalsodiscoveredthattheadditionofmethylboratetosodiumhydridemaintainedat250°providedamixtureofsodiumborohydrideandsodiummethoxideH.I.SchlesingerSchlesinger,H.C.Brown,A.E.Finholt,J.Am.Chem.Soc.75,205(1953)..Thisalsoprovidesthebasisforthepresentindustrialprocessforthemanufactureofsodiumborohydride.Atthisstagetheywereinformedthattheproblemsofhandlinguraniumhexafluoridehadbeenovercomeandtherewasnolongeranyneedforuraniumborohydride.TheywereonthepointofdisbandingthegroupwhentheArmySignalCorpsinformedthatthenewchemical,sodiumborohydrideappearedverypromisingforthegenerationofhydrogen/nobel_prizes/chemistry/laureates/1979/brown-lecture.pdftoinflatesignalballoon.Atthattime,therewasnodoubtaboutthefactthatNaBH4shouldreactwithwatertoliberatehydrogen.Someconcernsremainedaboutthesafetyofthereaction.Whentheytryforthefirsttimetoliberatehydrogenbyhydrolysistheborohydridewasplacedinaflaskandtheentireassemblywasputbehindanexplosionscreensinceitwasnotknowhowviolentthereactioncouldbe.Incredibly,theborohydridedissolvedinthewaterwithoutexplosionandwithslowhydrogenevolution,anditwasdiscoveredthatsodiumborohydridepossessesanunusualstabilityinalkalinewaterC.Herbert,H.C.Brown,R&DInnovatorVolume2,Number8,August1993.Severalstudyhavebeenthenconductedonhydrolysisofsodiumborohydride.ItwasfoundthatitisveryfastatlowpHandthathighpHvalues,preventwaterhydrolysisS.C.Amendola,etal.,Int.J.HydrogenEnergy25(2000)969–975..Inpresenceofcatalyser(cobalt,nichel,iron)thereactionisquitefastandcompletealsoathighpH.ArmySignalalsoproposedtostudythenewcompoundforrocketengineH.I.Schlesinger,FinalReporttoSignalCorpsGroundSignalAgencyonContractNo.W3434-SC-174,PB-6331,1944.buttheprojectwasstoppedfewyearslater.Atthatagetechnicianstoldthatsodiumborohydridewouldhaveapossibilityforciviluseattheendofthecentury.Morethan60yearhavebeenpassedandnowitcouldbetherighttimeforsodiumborohydride.Severalcarmakersannouncedtheirintentiontopowerhybridhydrogencarwithsodiumborohydride.DaymlerChryslerbuiltaprototypeapplyingthetechnologythatusethatsaltforfuellingafuelcell(theNatrium,overaChryslerTown&Countrymodel).EvenPSA-Peugeotbuiltaprototypewithruteniumascatalyser,theH2Omodel.Aliquidsolutionhalfweightsodiumborohydridehalfweightwater,stabilizedwithsodiumhydroxide,delivershydrogen(throughaRucatalyser)withanenergeticratio,involume,similartogasoline.MillenniumCell(whichhaspatentsoncatalyserandsystemsH.I.Schlesinger,H.C.\o"HerbertC.Brown"Brown,B.Abraham,A.C.Bond,N.Davidson,A.E.Finholt,J.R.Gilbreath,H.Hoekstra,L.Horvitz,E.K.Hyde,J.J.Katz,J.Knight,R.A.Lad,D.L.Mayfield,L.Rapp,D.M.Ritter,A.M.Schwartz,I.Sheft,L.D.Tuck,A.O.Walker,“Newdevelopmentsinthechemistryofdiboraneandtheborohydrides.Generalsummary”\o"JournaloftheAmericanChemicalSociety"JournaloftheAmericanChemicalSociety1953,volume75,pages186-90H.C.Brown,H.I.Schlesinger,I.,Sheft,D.M.Ritter,J.Am.Chem.Soc.75,192(1953).H.I.SchlesingerSchlesinger,H.C.Brown,A.E.Finholt,J.Am.Chem.Soc.75,205(1953)./nobel_prizes/chemistry/laureates/1979/brown-lecture.pdfC.Herbert,H.C.Brown,R&DInnovatorVolume2,Number8,August1993S.C.Amendola,etal.,Int.J.HydrogenEnergy25(2000)969–975.H.I.Schlesinger,FinalReporttoSignalCorpsGroundSignalAgencyonContractNo.W3434-SC-174,PB-6331,1944.Air-Attack_comNews-USAFContinuesFuelCellResearch.htmEXPERIMENTALThehydrolysisinthevaporphaseofsolidNaBH4wasconductedinaoven.About1.0gramofcatalyzedsolidNaBH4wasplacedintheoveninpresenceofwatercontainedinaseparatecontainer.TheNaBH4wascatalyzedwithvariousmetalsalts(Co,NiorFe)ataconcentrationofabout2%mol.Theoutletoftheovenwasconnectedtoagraduatecylinderfilledwithwater.Theevolutionofhydrogenwasfollowedbywaterdisplacement.Thetemperatureoftheovenwasraisedfromroomtemperatureupto95°C.afterTheproductofhydrolysiswascharacterizedbyX-raypowderdiffractionusingaMiniflexRigaku(Cuk-radiation).Cartridgeswerepreparedbyusingthesamemixture(NaBH4+catalyst).Blottingpaperwasusedtopreparethecartridges.ThecartridgeswerefilledwithNaBH4withaweightrangingfrom30upto150g.Thecartridgewereinsertedinametallicreactor.Thereactorisa6cmdiameter6cmhighcylinder.Liquidorvaporizedwaterwasintroducedbypumpingitwithacontrolledpumpintoathermocontrolledheater.Theamountofwaterwasrecordedbyusingaliquidflowmeter.Thehydrogenevolvedwascollected,filteredtoremovewatervaporandmeasuredbyusingagasflowmeter.ENEAACTIVITIESThenewhydrogenreleasingsystemdevelopinginENEAisbasedonsolidNaBH4whichishydrolyzedwithwaterorsteamP.P.Prosini,C.CentoandP.Gislon,ItalianpatentRM2006A000221.Tomakethereactionveryfastacatalystwasused.Figure3showtheamountofhydrogenevolvedwhen1.0gramofcatalyzedNaBH4isputinpresenceofwatervaporinequilibriumwithliquidwateratvarioustemperatures,rangingfrom40toP.P.Prosini,C.CentoandP.Gislon,ItalianpatentRM2006A000221Figure3.Volumeofhydrogenevolvedasafunctionoftimefrom1.0gofNaBH4inpresenceofwatervaporatvarioustemperature.Thecatalystwasnickelacetate2%mol.Thepresenceofcatalystissoeffectivethathydrolysiscanbeconductedalsoatroomtemperature.Byincreasingthetemperatureobviouslytherateofhydrogenproductionincreases,andthereactiontimedecreases.Independentlyfromtemperatureaboutthetheoreticalamountofhydrogenwasrecovered.Fortemperaturelowerthan70°Candfortimelowerthan100min,thereactionseemsindependentfromtemperature.Forlongertimesitisevidentaprogressiveincreaseofthekineticofthereactionasthetemperatureincreases.Asecondreactiontakesplaceandtheactivationenergyofthisreactionissohighthat,fortemperaturehigherthan70°C,thereactionbecomesthefasterone.Figure4showsthevolumeofhydrogenevolvedrelatedonlytothesecondreaction.Itwasobtainedbysubtractingfromthecurvesplottedinfigure3theconstantcontributeduetothefirstreaction.Inthesamefigureitisplottedthehalf-lifetimeasafunctionofthetemperature.Fromthesedataanewgraph(Figure5)wasobtainedbyplottingthenaturallogarithmoftheinverseofthehalf-lifetimeasafunctionoftheinverseofthetemperature(inKelvin).Figure4.TworeactionsconcurredtoNaBH4hydrolysis.Thevolumeofhydrogenevolvedrelatedonlytothesecondprocessisplottedasafunctionoftime(left).Inthesamegraphitwasreportedthetemperatureasafunctionofthehalf-time(right).Figure5.Plotofthenaturallogarithmoftheinverseofthehalf-lifetimeasafunctionoftheinverseofthetemperature(inKelvin).Datawereobtainedfromfigure4.AtypicalArrheniusbehaviorwasobserved.Theactivationconstantwasfoundtobe29kJ/mol.AfterhydrolysisthesamplephasepuritywasanalyzedbyX-Raypowderdiffraction.Figure6,7,and8showthediffractogramofthreerepresentativesamples. Figure6.X-Raydiffractogramfortheproductobtainedatroomtemperature.ItwasidentifiedasNaBO2*4H2O(JPCS06-0122). Figure7.X-Raydiffractogramfortheproductobtainedat70°C.ItwasidentifiedasNaBO2*2H2O(JPCS06-0122). Figure8.X-Raydiffractogramfortheproductobtainedat90°C.ItwasidentifiedasNa2B2O4*H2O(JPCS20-1078). Theproductobtainedintherange30-80°CwasmainlyNaBO2*2H2O.Inthisrangethetotalreactioncanbedescribedas:NaBH4+4H2O→NaBO2*2H2O+4H2 (3)Whileathighertemperaturewehave:2NaBH4+H2O→Na2B2O4*H2O+4H2 (4)Figure9.A30g.NaBH4filledcartridge.Figure10.Pulsetestforhighhydrogenreleasingrate.Thehydrogenflow(redline)isplottedversustime.Thetotalvolumeofhydrogen(blueline)wasobtainedbynumericalintegration.Theexperimentwasconductedbystoppingandrestartingthewaterflowwitha30gNaBH4cartridge.Thewaterwasheatedat60°C.Thenwetriedtoincreasethesizeofthereactortoobtainlargehydrogenproduction.Thefirststepwasthedevelopmentofareactorabletocontainupto150gramsofNaBH4.Figure9showatypicalcartridgecontaining30gramsofNaBH4.Thecartridgehasacylindricalshapeanditcanreleasemorethan50litersofhydrogen.Tostorethesameamountofhydrogeninthesamecartridgevolumebycompressionweshouldreachtheimpressivepressureof2000atm.!Figure10showsthevariationofhydrogenflowasafunctionoftime.Therewasagoodresponseofthesystemtosustainveryhighrateforfewminutes.Thesystemwasalsoabletoeasilyrestartafterprolongedpauses.Attheendofthereactionabout54litersofhydrogenwasreleased.Figure11showsthefacilityofthesystemtoreleasevarioushydrogenflowbysimplychangingthewaterflow.Thereactorwasfilledwith73gcartridge.Theamountofwatervariedduringtherunfrom0.2up1.0ml/min.Consequentlythehydrogenflowchangedupto0.6litersperminWearenowengagedtoincreasethesizeofthecartridgeupto1.5kg.Thereactorisverysimilartotheprevioususedreactoranditwasobtainedbyrepeatingthesingleunitabouttentimes.Ithasatubularshapeofabout6cmofdiameterand60cm.Figure11.Constantflowhydrogenreleasingtest.Theamountofwaterwasprogressivelyincreasedfrom0.2to1.0ml/min,step0.2(blueline).Incorrespondencetheamountofhydrogenincreasedproportionally(redline).ThenextstepInbrieftimeitwillpossibletoscale-uptheNaBH4cartridgeuptoautomotivepurpose.Theaimistodevelopa10litersrechargeablecartridges,filledwithNaBH4.Thecartridgeweightisabout8kg;eachcartridgeisabletodeliverabout1.6kgofhydrogen.Thecartridgescanbecollectedonpalletsandmovedbytrainortruck.Thesameinfrastructuresusedfortransportationcouldthenbeusedtotransporttheexhaustedcartridgeforregeneration.Thecarfuellingcouldbeperformedinareasimilartotheactualservicestations.Acarcanbefullyfuelledbythreecartridgesthatallowtostoreabout4kgofhydrogen.Theusedcartridges(one,twoorall)canberemovedandsubstitutedbynewcartridges.Contemporarilyupto25litersofwatershouldberefuelled.Thecarcanbefullyrefuelledinwithin2-3minutes.Forhydrogenproduction,apumpflowsthewaterthroughaheater;thehotwatercomesincontactwiththeNaBH4(figure12).Pureandhumidifiedhydrogen,asrequestedbyfuelcells,isproducedinasimpleandsureway.Thesecurityisintrinsicasthehydrogenisproducedonlywhenneeded,bythepumpactivation.Thereisthereforeneverpressurizedhydrogen,orhydrogenoverproduction.Thehydrolysisisanexothermicreactionandpartofthisheatcanbeusedforwaterwarming,theotherremoved.AmongthedifferentwaysofNaBH4utilization,thecartridgepresentshighefficienciesintermsofgravimetricenergydensity.Fromthedatacollected,wecanstoreabout4kgofhydrogenin20kgofcartridgesand25kgofwater.Thehydrogenweightpercentcontentofthesystem,consideringboththeweightofNaBH4andwater,is8.8%PumpPumpHydrogenoutputHeater NaBH4CartridgeWatertank Figure12.Sketchshowinghowthesystemcouldworkonboard.Thepumpstartstointroducewaterfromthewatertankintotheheater.ThroughtheheaterwaterpassestotheNaBH4cartridgeandreactionproduceshydrogenthatiscollectonthetopofthecartridge.Afterthestartuptheheatercanbeturnoffsincetheheatofreactionprovidestoincreasethewatertemperature.Bythisideaitwillbepossibleinshorttimestorealizeanhydrogendevicewithveryinnovativeperformance,asitsatisfiestheDOElongtermgoals.produceshydrogenthatiscollectonthetopofthecartridge.Afterthestartuptheheatercanbeturnoffsincetheheatofreactionprovidestoincreasethewatertemperature.ThemainproblemremainstheNaBH4cost.Itsannualproductionisquitelow(about104-105tonperyear,thedataarenotconfirmed)ifcomparedtopetrochemicalproducts(over109tonperyear).TheNaBH4isnowadaysobtainedindustriallybytrimethylborate,synthesizedasdescribedin(5): NaBO2+3CH3OH→B(OCH3)3+H2O+NaOH (5)Thetrimethylborateisthenreactedwithfourmolesofsodiumhydridetoformamoleofsodiumborohydride: B(OCH3)3+4NaH→3NaOCH3+NaBH4 (6)Thesodiumhydrideisusuallypreparedbyhydrogenandmetallicsodium 2Na+H2→2NaH (7)ThepresentcostofNaBH4is40€/kg(for50kgbatches).Thiscostdoesnotreflecttherealcostanditismainlyduetothefactthattheproductinterestsonlynichemarkets.Tohaveonboard4kgofhydrogen20kgofNaBH4arenecessary.The4kg“full”costisnowadays€800.ScalelawscouldinshorttimesreducestheNaBH4toaboutonetenth.ResearchactivitiesonNaBHAbout60-70%ofNaBH4costisrepresentedbymetallicsodiumcost.ThislatterispresentlymainlyproducedbyelectrolysisoffusedNaCl.Sodiumisaveryelectropositivemetal(E°=-2.17Voltvs.H).Itspreparationismainlycarriedoutviaelectrochemical,byafuseof40%NaCland60%CaCl2.Thismixtureformsaneutecticwhosemeltingpointisabout580°C;atthattemperaturetheelectrolysiscanbecarriedout.Usuallyithasperformedat600°CincellscalledDownscellsJ.C.Downs,U.S.Patent,1,501,756(July151924),withastainlesssteelcylindricalcathodeandgraphiteanode,woundbyametallicnetworkactingasadiaphragm;thislastavoidsthatchlorinegeneratedbytheanodecouldcontaminatethecathode.Thechlorineisthencollectedandutilizedinpolymerfabrication.Thesodiumformedatthecathodeisliquid(meltingpoint=J.C.Downs,U.S.TheTekkoshamethodT.Yamaguchi,Chem.Econ.Eng.Rev.(1)24,Jan.1972utilizesamercuryelectrode;thesodiumformsamixturewithitandisextractedbyvaporization.Thecelloperativetemperatureis220-240°Casthemeltingiscomposedbysodiumhydroxide,sodiumiodideandsodiumcyanide.T.Yamaguchi,Chem.Econ.Eng.Rev.(1)24,Jan.1972TheglobalenergeticefficiencycanbecalculatedbycomparingtheenergytheNaBH4cansupplytothecartowhatisnecessaryforitsproduction.Electricpowerfromtraditionalorrenewablesourcescanbeutilizedtoproducemetallicsodiumatabout3-5Volt.ThisisconvertedintoNaBH4andstoredinthecar.Whennecessary,hydrogenisgeneratedandburnedinthefuelcellgeneratinga0.8Volt.Consideringthecurrentefficiency,respectively78and98%,thetotalenergeticefficiencyisinbetween12and24%,dependingonsodiumproductionprocess.Thatvalueiscomparablewithaninternalcombustioncar.FromaneconomicalpointofviewtheenergeticcostforeverykWhproducedbythevehicleisabout4-8timestheelectrickWhcost.It’sworthtonotethatastheelectricitycanbeproducedbyrenewable(Fig.12)usingsodiumborohydrideallowstoreduceatleastpartiallythefossilfuelsutilizationintransportation,reducingconsequentlytheCO2concentrationandsatisfyingthereforetheKyotoagreement.ApossiblealternativeformetallicsodiumproductionisrepresentedbythereactioninvolvinghydroxideinturnsthatchlorideY.Wuetal.,MillenniumCellInc.,FY2004ProgressReport.ThemainadvantageisthatoxygeninsteadthanchlorideisproducedattheanodeandthiswouldallowtoclosetheloopasshowninFig.13.Moreoveritwouldbepossiblebothtoreducethemeltingtemperature(morethan250°C)andloweringthecellvoltagegainingalotonprocessefficiency,asshowninTab.1.AlternativelyMagnesiumHydridecouldbeutilizedassuggestedbySudaS.Sudaetal.Y.Wuetal.,MillenniumCellInc.,FY2004ProgressReportS.Sudaetal.JournalofAlloysandCompounds349(2003)232–236Na2B4O7+4MgH2→2NaBH4+4MgO+B2O3 (8)NaproductionactualmethodNaproductionmethodbyMillenniumCellMediumofreactionNaClmeltNaOHmeltWorkingtemperature600ºC350ºCAnodeproductClorite(Cl2)Oxygen(O2)Theoreticalvoltage3.42V3.07VActualvoltage~5.5V~3.2VDiaphragmPorousceramicseparatorNa-ionconductivemembraneTable1.Comparisonbetweentheactualwaytoproducesodium(ontheleft)andthewayproposedbyMillenniumCell(ontheright).ElectricpowerfromrenewablesourcesElectricpowerfromrenewablesourcesElectricpoweronboardsourcesFigure13.Electricpowerfromrenewablesourcescanbeusedtoproducemetallicsodium.SodiumcanbeconvertedinNaBH4cartridgesabletoproducehydrogenondemand.Afuelcellconvertsthehydrogeninelectricpoweronboard.Thiscouldrepresentafirstwaytopowerelectricvehicleswithrenewablesources.UsingmorecommonandcheaperelementsthanMagnesiumwouldreducethecostsevenmore.Afurtherpossibilityarisesfromdiborane.IneffectdiboranehasenergyslightlyhigherthanNaBH4Y.Wu,MillenniumCellInc.,GCEP,StanfordUniversity,April14-15,2003.IftheenergyofformationofdiboranestartingfromtrimethylborateY.Wu,MillenniumCellInc.,GCEP,StanfordUniversity2H2H2O2H2O4H2H3BO3NaBO24NaOH2O23MeOH3H2O4NaH3NaOMeNaBH4B(OMe)3+8electronsFigure13.CloseloopfortheproductionofNaBH4.Thekeyoftheprocessistheelectrolysisofwaterinalkalinemediumtoproducesodiumhydrideandoxygen(yellowsector).SodiumhydrideisusedforNaBH4regeneration(ontheleft).NaBH4isusedtoproducedhydrogenthatcombiningwithatmosphericoxygenproducewaterandsodiumborate(ontheright).ThislatteriscollectedforNaBH4regeneration.Itresemblesthesituationoccurred60yearsago,sincethediscoveryofanewwaytosynthesizediboranefromtriethylboratewasthekeyfactortoobtainlargeamountofthischemical.InENEAwearestudyingtheuseofcomplexingagentstosynthesizethediboranestartingfromtriethylborate.Thecomplexingagentwasrecycledduringtheprocess.Theprocessisinprogressand,atthemoment,nomoreinformationcanbegiven.Fromanenergeticpointofview,sincethesynthesizeofdiboranefromtrialkylboratecanbeconductedwithhydrogen,itispossibletoreducetheamountofsodiumhydrideof75%.Byreducingtheenergeticcostofproduction,theenergeticconversionrateofthesoobtainedNaBH4willresultstronglyincrease,allowingabetterenergyefficient.NaClNaCl4NaH(B(OEt)3)B2H6B(OEt)3NaBO23310kJ/moleNaBH4Na1666kJ/moleNaBH4356kJ/moleNaBH449kJ/moleNaBH4XkJ/moleNaBH4NaBH4TraditionalwayProposedwayFigure14.Thechemicalpathwayproposedtoreducetheenergeticcostoftheprocess.Theenergyofformationofdiboranecouldbedecreasedbyintroducingacomplexagent.Insuchawayitwouldbepossibletoreducetheamountofsodiumhydrideof75%.ConclusionsThankstotheNaBH4cartridge,thehydrogencarisbecomingareality.Inshorttimeitwillbepossibletoreduceourdependencefromhydrocarbonfuels.Itwillbethefirststeptowardsaliberalizationofthemarketlaws,toomuchlinkedtotheoilbarrelcost.Sodiumborohydrideappearsliketheperfectcandidatetoreplaceliquidorgaseousfossilfuel.Sodiumisaomnipresentelement.Boronisnotsoabundantbutitispresentinnatureconcentratedinsomegeothermicsites.Itscostisverylow.Developinganintegratedsystemofsodiumborohydrideproductionanddistributionwouldgivetotheproductaconsiderableaddedvalue,withapositivesocial-economicalindexesgrowth.Strategicactivitiesusefulforhydrogencarimplementationarestill:newNaBH4regenerationprocessesforreducingproductioncoststheonboardintegrationofNaBH4hydrogengeneratorswithfuelcellsthecreationofanetworkfordistribution,managingandregenerationofNaBH4ENEAresearcherhavealreadysetacollaborationwithSocietàChimicaLarderello(theItalianproducerofboricacid),RohmandHass(theproducerofsodiumborohydride)andFIATgroup(Italiancarmakers)andotherpartnerstodevelopanhydrogenvehicleusingNaBH4cartridges.Adeeperefforthastobedonebypublicinstitutions,industrialcompaniesandpublicopinioninordertoturnthehydrogencarintoreality.AcknowledgmentWewouldliketotankENEAcolleaguesforhelpfuldiscussionandencouragement.AmongthemCinziaCentoandGiuliaMonteleonearekindlytankedforthehelpincarryingoutthehydrogenmeasurements.基于C8051F单片机直流电动机反馈控制系统的设计与研究基于单片机的嵌入式Web服务器的研究MOTOROLA单片机MC68HC（8）05PV8/A内嵌EEPROM的工艺和制程方法及对良率的影响研究基于模糊控制的电阻钎焊单片机温度控制系统的研制基于MCS-51系列单片机的通用控制模块的研究基于单片机实现的供暖系统最佳启停自校正（STR）调节器单片机控制的二级倒立摆系统的研究基于增强型51系列单片机的TCP/IP协议栈的实现基于单片机的蓄电池自动监测系统基于32位嵌入式单片机系统的图像采集