甲醇制对二甲苯联产低碳烯烃催化剂ZSM-5改性研究  

Study on Modification of ZSM-5 Catalyst for Methanol to p-xylene Co-production of Low Carbon Olefins

作　　者：时一鸣 刘丹 陈星月 代成义[1] 马晓迅[1] SHI Yiming;LIU Dan;CHEN Xingyue;DAI Chengyi;MA Xiaoxun(School of Chemical Engineering, Northwest University, International Science and Technology Cooperation Base of MOST for Clean Utilization of Hydrocarbon Resources, Chemical Engineering Research Center of the Ministry of Education for Advanced Use Technology of Shanbei Energy, Shaanxi Research Center of Engineering Technology for Clean Coal Conversion, Collaborative Innovation Center for Shanbei Energy and Chemical Industry Development, 710069 Xi’an, China)

机构地区：[1]西北大学化工学院,碳氢资源清洁利用国家国际科技合作基地,陕北能源先进化工利用技术教育部工程研究中心,陕西省洁净煤转化工程技术研究中心,陕北能源化工产业发展协同创新中心,西安710069

出　　处：《煤炭转化》2020年第5期1-9,共9页Coal Conversion

基　　金：国家重点研发计划项目(2018YFB0604901);国家自然科学基金资助项目(21536009,21706210).

摘　　要：采用等体积浸渍法制备了ZnO,SiO2,P2O5与MgO复合改性HZSM-5催化剂,并在固定床反应器中系统地研究了复合改性对甲醇制对二甲苯联产低碳烯烃反应的影响。通过SEM,TEM,XRD,N2吸附-脱附以及氨程序升温脱附(NH3-TPD)对催化剂进行表征,揭示了改性方法与催化性能之间的构效关系。结果表明:Zn的引入有效地提高了HZSM-5的反应活性,这是由于锌改性降低了强酸强度和强酸量,并形成了ZnOH+脱氢活性中心。再通过SiO2,P2O5和MgO进行多重修饰,产生的协同效应能够有效地消除外表面酸位,同时缩小孔口,抑制了对二甲苯异构化、烷基化等副反应以及氢转移反应,从而将二甲苯中对二甲苯选择性提高至79.3%,乙烯在C2烃类的选择性高达98.7%,芳烃和C2~C4烯烃总收率可达到84.1%。The ZnO,SiO2,P2O5 and MgO composite modified HZSM-5 catalyst was prepared by using an iso-volumetric impregnation method,and the effects of the composite modification on the reaction of methanol to xylene co-production of xylene in a fixed bed reactor was systematically studied.The catalysts were characterized by using the SEM,TEM,XRD,N2 adsorption-desorption,and ammonia temperature-programmed desorption(NH3-TPD)methods.The structure-activity relationship between the modification method and catalytic performance was revealed.The results show that the introduction of Zn effectively improves the reactivity of HZSM-5.This is because the modification of zinc reduces the strength and quantity of strong acids,leading to the formation of the ZnOH+dehydrogenation active centers.Multiple modification through SiO2,P2O5 and MgO can produce a synergistic effect that can effectively eliminate the acid surface on the external surface,while reducing the pore size,and inhibiting side reactions such as p-xylene isomerization,alkylation,and hydrogen transfer reactions.The selectivity of the para-xylene in xylene is increased to 79.3%,the selectivity of ethylene in the C2 hydrocarbons is as high as 98.7%,and the total yield of the aromatics and C2-C4 olefins can reach 84.1%.

关 键 词：对二甲苯 低碳烯烃 ZSM-5分子筛 煤基甲醇 多重改性 

分 类 号：TQ426[化学工程]