煤的孔隙结构与反应性关系的研究进展_张占涛

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  28 4200510COALCONVERSIONVol.28 No.4Oct.2005   *(2003CB214500).1);2)、,,710049 :2005-06-22;:2005-08-10煤的孔隙结构与反应性关系的研究进展*张占涛1) 王 黎2) 张 睿1) 张 丽1)    煤在气化、燃烧与活性炭制备等热化学转化过程中,均存在着孔隙结构与表面积的变化.煤的孔隙结构变化特征的研究是煤炭高效合理利用的基础.从煤的孔隙结构的表征、反应过程中孔隙结构变化以及孔隙结构模型三方面总结了煤的孔隙结构与反应性关系领域的研究现状,并对今后的研究重点进行了展望,即加强孔隙结构与反应性关系通用规律和催化剂对孔隙结构影响两方面的研究. 煤,孔隙结构,反应性 TQ5300 引 言,.,.2080,,,,.:1)(SAXSSANS);2)TGA,;3),().1 煤的孔隙结构:;..();,.,.r,()X,Sf(r).:1)(2nm),,;2)(2nm~50nm),,,,,;3)(50nm),,,.2 煤的孔隙结构的表征、,、,.,:(N2CO2)、、(SEMTEM)(SAXSSANS)..77KN2298KCO2,,;30nm,;,.,,,,.,SAXSSANS,SAXS,,.SANS:1),Bragg,;2)SANS,,,(、、),.,、.,SANSSANSTEM、,.[1-5]Hall[2,3](CM-SANS).SANS,,SANS“”,,.Calo[4,5]SANSWyodak.SANS,Wyodak(),,,,,Wyodak;.FosterSAXS.3 煤的孔隙结构与反应性关系研究.,,(H2O,CO2,O2);,.,,.3.1 ()Davini[6]7,7..Ghetti[7],,.[8]、、,,,.:,,,;,,,,.[9],:,.30nm,;,,,;25s,,,.,,.Bhatia[10-12],,.,,,,,20%~60%.Chin[13-15].Yang[16-18],,.,,,,.(ASA),O2ASA.,.Bhatia[10,19],634                              ,95%,.Takashi[21],,,.3.2 ,.Takashi[20]850℃,1MPa,Ni,,(Ni2~3).Ni;,6nm(1).[8],.1 Fig.1 Sketchesofthegasificationandcatalyticgasificationmodela——Beforegasification;b——Gasifiedwithoutcatalyst;c——Gasifiedwithcatalyst  [21](Ni,Ca,Ni+Ca)4,CO2,XRD,TGA,XRDXPS.,,,Ca,Ni.XRDXPS,Ca,NiCaONi,.,Ni.,[22],,Ca,.[23]KOHNaOH,NaOH,KOH.4 煤的孔隙结构模型,、、,,().:、.,,.4.1 Petersen[24],,.,,.Petersen(S)(X):S=2πLEXE(1-13XE)(1)X=XE(1-233XE)(2):LE;XE,rpLE.XE=πrpLE(3),,Szeke-ly:x=X0(1-X0)1+ksCntrp02G-1-ksCntrp0G-1-1(4)  ,,.:,;,,64                                            2005,,.4.2 [25],10.,,——:;,.,,.,,x≈X-X01-X0(5):x,X,X0.,:dxdf≈2(1-x)ln2×ln(11-x)(6)x≈1-2f2          (7):f,.f=1t1/2(8):t1/250%.x-f,.xf,.Tseng[26],.[27],,,,,.4.3 4.3.1 随机孔模型的提出Bhatia[10,19](RPM)..,.RPM,(),,.RPM,:x=1-exp[-f(1+Jf4)]    (9)dxdt=(1-x)[1-Jln(1-x)](10):f,J,.f=KsCnS0t1-X0(11)J=4πL0(1-X0)S20(12):S0,L0,X0,,f(r).S0=2π∫∞0rf(r)dr(13)L0=∫∞0f(r)dr(14)X0=V0=π∫∞0r2f(r)dr(15)  Gavalas,.、.,:x=1-exp[-2πt(A0t+2A1)](16)dxdt=4π(1-x)A21+A0ln(1-x)(17):A0,A1.,;,.4.3.2 随机孔模型的改进与应用RPM、,,.,,、.,RPM,、CO2H2O654                              [28-33],(1).[12-15,34-36]1 Table1 ModificationandapplicationofrandomporemodelAuthorTimeModelModifyEvaluationBhatia1980Randomporemodel(RPM)dxdt=ksS0(1-X0)(1-x)1-Jln(1-x)NoneRPMsuitsfliud-poroussolidreactionGavalas1980Randomcapillarymodel(RCM)dxdt=4π(1-x)A21+A0ln(1-x)NoneRCMcouldbeappliedtocharreactionsBhatia1996Discreterandomporemodeldxdt=ksS0(1-X0)(1-x)(1+T)1-JEln(1-x)Discreteofpores(1+T)ObtainedeffectivestructureparameterΧGupta2000Modifieddiscreterandomporemodel(MDRPM)dxdf=exp(-V)1-X0eS0dn-df+πe2L0dn-2dfDifferentreactivityofAandA0A=k2k1MDRPMcouldbetterexplainthecharcombustion(gasification)thanRPMStruis2002Extendedrandomporemodel(ERPM)dxdt=A0(1-x)1-Jln(1-x)×[1+(p+1)(bt)p]Catalyticeffect[1+(p+1)(bt)p]ERPMagreewellwithexperimentdata;newparameterslackrationalityGeChin1987ApplicationofRPMdxdt=kS0pH2O(1-x)1-Jln(1-x)CatalyticeffectandH2OpressurekpH2OConsideredtheinfluenceofcatalyticeffectandH2OpartialpressureChi1989ApplicationofRPMdxdt=ksS0(1-X0)(1-x)1-Jln(1-x)UsingRPMtointerprettheexperimentalkineticsbehaviorsofchar-steamgasificationXieKechang1990ApplicationofRPMS=S0(1-x)1-Jln(1-x)Thecorrelationbetweensurfaceareaandconver-sionofPinlu,Datong,DongshanandJinchengcoalcharstoCO2gasificationaccordwithRPMOchoa2001ApplicationofRPMandRCMdxdt=dθdt(1-x)1-Jln(1-x)Thebehaviorof2Argentineanlow-rankcoalcharstoCO2gasificationwassatisfactorilydescribedbyRPMandRCM  Bhatia[10],.,(2),.,:r=r0+ne(18):r0,e,n.:dxdt=(1-x)(1+T)1-JEln(1-x)(19)TJE:T=πeL0S0(20)JE=J(1+T)2(21)S0,L0:S0=2π∫∞0r(r0,f)f(r0)dr0(22)2 rFig.2 SchematicdiagramofreactivesitessurroundingacylindricalporeofradiusrL0=∫∞0f(r0)dr0(23)  ,Gupta,.A:66                                            2005A=k2k1(24),k1,k2.A,P,:dxdf=exp(-V)1-X0eS0dn-df+πe2L0dn-2df(25):dn-df=∑∞n=0ndPndt(26)V=π∫∞0∑∞n=0Pnr2(r0,n,f)f(r0)dr0(27)dn-2df=∑∞n=0n2dPndt(28)dP0df=-P0A(29)dP1df=-P1+P0A(30)dPndf=-Pn+Pn-1(31):P,,,Rayleigh,.Struisa[14,15](),,,.dxdt=A0(1-x)1-Jln(1-x)×[1+(p+1)(bt)p](32)x=1-exp[-f′(1+Jf′/4)]f′=A0t[1+(bt)p](33):A0,b,p,f′.Struisa,,.,,,.,:1),、();2),.4.4 [37,38],.,,:;;,.,,.Sd,SrSre:Sd=4πr2θ(34)θ=θ0+(1-θ0)(1-A)B(35)Sr=4πr2Ard(1-θ0)(36)Sre=Sr(1-A)(1-B)(37):θ,θ0,AB,r,Ar,d.,.[39]、.5 结束语,,,,.,,,,;,(),.,,:1);2)().,.674                                 [1] AntxustegiMM,HallPJ,CaloJM.TheUseofContrast-matchingSmall-angleNeutron-scatteringTechniquestoMonitorClosedPorosityinCarbons.JournalofCollidandInterfaceScience,1998,202:490-498[2] HallPJ,AntxustegiMM,CaloJM.DevelopmentofPorosityinPittsburghNo.8CoalCharasInvestigatedbyContrast-matchingSmall-angleNeutronScatteringandGasAdsorptionTechniques.EnergyFuels,1998,12(3):542-546[3] HallPJ,BrownaS,FernandezaJetal.TheEffectsoftheElectronicStructureofMicroporesontheSmallAngleScatteringofX-raysandNeutrons.Carbon,2000,38:1257-1259[4] CaloJM,HallPJ,AntxustegiM.CarbonPorosityCharacterizationViaSmallAngleNeutronScattering.ColloidsandSur-facesA:PhysicochemicalandEngineeringAspects,2001.219-232[5] CaloJM,HallPJ.TheApplicationofSmallAngleScatteringTechniquestoPorosityCharacterizationinCarbons.Carbon,2004,42:1299-130

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