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1、摘要本文采用共浸漬法制備了過渡金屬磷化物氧化態(tài)的前驅(qū)體,通過H2程序升溫原位還原方法制備了一系列負(fù)載型過渡金屬磷化物催化劑。磷化物的生成過程及結(jié)構(gòu)用XRD、原位XRD、BET和TPR作了表征。在壓力2MPa、體積空速3~、氫液tt,300/1(VⅣ)條件下,以二苯并噻吩(DBT)和喹啉(Q)為模型化合物考察了催化劑的HDS和HDN活性,采用不同的進(jìn)料順序考察了加氫脫硫和加氫脫氮之間的相互影響,比較了不同催化劑的加氫活性。結(jié)果表明,Ni2P的最佳擔(dān)載量對HDS為25wt%,對HDN為30wt%,最佳Ni/P摩爾比
2、為2/1.6,最佳還原溫度為600。C,氫氣流速≥80ml/min。單獨脫硫和單獨脫氮時,Ni2P/Si02催化劑表現(xiàn)出較高的加氫活性,在喹啉存在下,DBT的轉(zhuǎn)化率顯著降低,DBT通過直接氫解生成聯(lián)苯的趨勢更顯突出,表明DBT生成環(huán)己基苯的加氫反應(yīng)路徑受到了抑制。加入DBT后,喹啉的脫氮率也明顯降低,DBT對喹啉的HDN反應(yīng)的影響主要體現(xiàn)在對喹啉的加氫反應(yīng)路徑的抑制,說明DBT和喹啉在催化劑的加氫活性位存在著強(qiáng)烈的競爭吸附。催化劑加氫活性順序為:Ni2P/Si02>NiMoPISi02>Ni2P/A1203。在
3、上述研究的基礎(chǔ)之上,以FCC汽油、FCC柴油為原料對Ni2P/Si02催化劑進(jìn)行了加氫性能測試。結(jié)果表明,在360℃、4MPa、體積空速2h~、氫油LL500/1(VⅣ)的條件下,對FCC柴油脫硫率為80.7%,脫氮率為45.6%,其中脫氮率高于傳統(tǒng)CoMoWS/7-A1203催化劑:在320℃、1.6MPa、體積空速4h~、氫油比300/1(V/V)的條件下,對FCC汽油脫硫率可達(dá)81%,烯烴飽和率9.9%,說明Ni2WSi02催化劑具有良好的汽油選擇性加氫脫硫性能。關(guān)鍵詞:磷化物,制備,表征,原位還原,加氫
4、脫硫SynthesisandHydrogenationPerformanceofSupportedTransitionMetalPhosphideCatalystsQuBenlian(OrganicChemistry)DirectedbyProf.LiuChenguangAbstractInthispaper,theseveraltransitionalmetalphosphidessupportedonsilicaandaluminawerepreparedbyin.situtemperature·progr
5、ammedreduction(TPR)ofoxidicprecursorsinflowingH2inafixedbedreactor.TheprecursorswereobtainedbyCO—impregnation.TheformingprocessandstructureofthephosphidescatalystswerecharacterizedbymeansofXRD,in.situXRD,BETandTPR.TheHDSandHDNperformancewereevaluatedinafixed
6、bedflowmicro.reactorusingdibenzothiophene(DBT)andquinoline(Q)asthefeedstockatconditionsofpressure2.0MPa,LHSV3h~andH2/oil300/1(v/v).TheeffectbetweentheHDSandHDNwereinvestigatedthroughdifferentfeedingproceduresatthesamemicro—reactor.Thehydrogenationactivitieso
7、fdifferentcatalystswereinvestigatedandcomparedeachother.TheexperimentalresultsshowthatthehighestHDSactivityisobservedatatotalloadingof25wt%Ni2P.30wt%forHDN.ThebestNi/Pmolarratiois2/1.6,reductiontempretureis600。C,H2flowrateishigherthan80ml/min.Ni2P/Si02cataly
8、stpresentsbetterhydrogenationactivitiesinHDSandHDNalone.InthepresenceofQ,theconversionofDBTremarkablydecreaseandthedirecthydrogenolysisformingBPbecomedominant,suggestingthatthehydrogenationroute