资源描述:
《Control of Molecular Composition of Tar by Secondary》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、Energy8zFuels1993,7,57-6657ControlofMolecularCompositionofTarbySecondaryReactioninFluidized-BedPyrolysisofaSubbituminousCoalJun-ichiroHayashi,*TsutomuKawakami,TomohiroTaniguchi,KabukiKusakabe,andShigeharuMorookaDepartmentofChemicalScienceandTechnology,KyushuUniversity,Fukuoka812,JapanMo
2、rioYumuraNationalChemicalLaboratoryforIndustry,Tsukuba,Ibaraki305,JapanReceivedJune4,1992.RevisedManuscriptReceivedSeptember22,1992Changesinthemolecularstructureoftarareinvestigatedinafluidized-bedreactordividedintotworegions:adensebedfortheprimaryreactionandafreeboardforthesecondaryrea
3、ctioninthegasphase.Thetemperatureinthedensebediskeptat600"Candthatinthefreeboardisvariedintherangeof600-900"C.Apulverizedsubbituminouscoal(C=76wt%1iscontinuouslyfedintothedensebed,andtarisrecoveredatthereactoroutlet.Thetarisseparatedbysolventextractionintopreasphalteneandasphaltene.Thea
4、sphalteneisfurtherclassifiedbycolumnchromatographyintosaturates,aromatics,phenolicethers,nitrogen-containingcompounds,andhydroxyliccompounds.ThearomaticsarefractionatedbyHPLConthebasisofthenumberofdoublebondspermolecule(db)intodicyclic(5db),dicyclic(6db),tricyclic(7db),tetracyclic(8db),
5、tetracyclic(9db),pentacyclic(10db),andpentacyclicandgreater(+11db)PAHs(polycyclicaromatichydrocarbons).EachhomologueischaracterizedbyFIMSand'HNMRtodeterminemolaryield,number-baseddistributionofaliphaticcarbonspermolecule,andnumber-baseddistributionofa-,j3-,andy-carbonspermolecule.Atfree
6、boardtemperaturesof600-700"C,detachmentofaliphaticsubstituentsproceedswithbondcleavageataryl-apositionsratherthana-j3andremotepositions.Decompositionofa-methylgroupsisnotobservedbelow700"C.Atafreeboardtemperatureof600"C,PAHswiththreetofouraliphaticcarbonspermoleculearemostabundant,andth
7、emolefractionofunsubstitutedPAHsisonlyca.5%foreachhomologue.At900"C,however,thefractionofunsubstitutedPAHsismorethan50%.Thestructuraldistributioninpyrolysisproductsisthuscontrolledbychangingthefreeboardtemperature.Introductionreactiontimeandtemperatureofflashpyrolysisontheyield