碱处理对钠型ZSM-5孔结构的影响 土木工程专业VIP免费

碱处理对钠型ZSM-5孔结构的影响摘要：在甲醇制烯烃(MTO)反应中，ZSM-5分子筛催化剂表现出来的高活性和高选择性导致其被一些微量金属离子改性，在反应中失活。在本文中，通过X射线衍射（XRD）、N2吸附-脱附、红外光谱(IR)、红外光谱加NH3分子探针(IR-NH3)来研究催化剂的失活机制和再生方法。这些特性表明结焦是造成催化剂失活的主要原因。为了使失活的催化剂再生，有两种方法，即：焙烧和甲醇抽滤，已被应用。N2吸附-脱附、红外光谱(IR)、红外光谱加NH3分子探针(IR-NH3)表征表明两种方法可以消除催化剂的结焦并且可以激活催化剂。X射线衍射（XRD）表明催化剂再生后结构没有发生变化。有趣的是，在甲醇制烯烃反应过程中再生催化剂表现出的催化性能比新的催化剂还要好。除此之外，焙烧激活能更彻底地消除结焦，然而，甲醇抽滤法可以更容易地在反应器内就地进行。关键词：甲醇；烯烃；ZSM-5；失活；再生Abstract:inthereactionofmethanoltoolefin(MTO),thehighactivityandhighselectivityofZSM-5zeolitecatalystshowedthatitwasmodifiedbysometracemetalions.Inthispaper,Xraydiffraction(XRD),N2adsorptiondesorption,infraredspectroscopy(IR),infraredspectroscopyandNH3molecularprobe(IR-NH3)wereusedtostudythedeactivationmechanismandregenerationmethod.Thesecharacteristicsindicatethatcokingisthemaincauseofcatalystdeactivation.Inordertomakethecatalystdeactivation,therearetwomethods,namely:roastingandmethanolfiltration,hasbeenused.N2adsorptiondesorption,infraredspectroscopy(IR),infraredspectroscopyandNH3molecularprobe(IR-NH3)characterizationshowedthatthetwomethodscaneliminatethecokingofthecatalystandactivatethecatalyst.Xraydiffraction(XRD)indicatedthatthestructuredidnotchangeafterregeneration.Interestingly,thecatalyticactivityoftheregeneratedcatalystintheprocessofmethanoltoolefinreactionisbetterthanthatofthenewone.Inaddition,theroastingactivationcanmorethoroughlyeliminatecoke,however,methanolfilteringmethodcanbemoreeasilyinthereactoronthespot.Keywords:methanol;olefin;ZSM-5;deactivation;regeneration目录摘要..............................................................................................................................1Abstract........................................................................................................................21.绪论...........................................................................................................................32.什么是ZSM-5分子筛...............................................................................................32.1化学组成与结构.............................................................................................42.2ZSM-5分子筛特性...........................................................................................4热稳定性........................................................................................................4耐酸性............................................................................................................4水蒸汽稳定性................................................................................................4憎水性............................................................................................................5不易积炭........................................................................................................5优异的择形选择性........................................................................................5吸附量............................................................................................