酸性及孔结构调变对IM-5分子筛催化MTP反应活性稳定性的影响  

Effects of Modification of Acidity and Pore Structure of IM-5 Zeolite on the Catalytic Performance in Methanol to Propylene Reaction

作　　者：张云鹏[1] 李明罡[1] 陈俊文[1] 邢恩会[1] 罗一斌[1] 舒兴田[1] ZHANG Yunpeng;LI Minggang;CHEN Junwen;XING Enhui;LUO Yibin;SHU Xingtian(Research Institute of Petroleum Processing,SINOPEC,Beijing 100083,China)

机构地区：[1]中国石化石油化工科学研究院

出　　处：《石油学报（石油加工）》2020年第1期17-27,共11页Acta Petrolei Sinica(Petroleum Processing Section)

摘　　要：分别采用复合酸(氟硅酸、硫酸)、四乙基氢氧化铵(TEAOH)溶液后处理方法对母体IM-5分子筛进行酸性和孔结构调变。通过XRD、N2吸附-脱附、NH3-TPD和29Si、27AlMAS NMR等手段表征改性IM-5分子筛的物化性能。结果发现,复合酸处理可以增加分子筛硅/铝摩尔比,且增加程度随氟硅酸质量的增加而增加;随着TEAOH处理时间的增加,分子筛的相对结晶度和孔结构参数均有一定程度提升。在反应温度480℃、反应压力0.1 MPa、甲醇与水质量比1/1、甲醇质量空速1.5 h^-1的条件下,考察了酸性及孔结构调变IM-5分子筛的甲醇制丙烯(MTP)催化性能。结果表明,酸性调变可以将母体IM^-5分子筛的寿命由3 h提高到19 h,且随着硅/铝摩尔比增加,丙烯收率不断增加,乙烯收率不断降低。而TEAOH后处理又可以继续将分子筛寿命提高至102 h,随着TEAOH处理时间增加,丙烯收率变化不明显,而乙烯收率不断增加。The modification of acidity and pore structure was carried out by acid and TEAOH treatment.Modified IM-5 zeolites were characterized with XRD,N2 adsorption,NH3-TPD and 29Si/27AlMAS NMR.Results show that the Al2O3/SiO2 ratio becomes larger with the increasing of fluorosilicic acid concentration.Moreover,the treatment of TEAOH increases not only the relative crystallinity,but also the specific surface areas and pore properties.Under the following optimized operating conditions:T=480℃,p=0.1 MPa,m(CH3OH)/m(H2O)=1/1 and MHSV(CH3OH)=1.5 h^-1,the catalytic properties of acid and TEAOH treated IM-5 zeolites were evaluated in the methanol to propylene(MTP)reaction.It demonstrates that the lifetime of acid-treated IM-5 zeolites increases to 19 h,much higher than that of parent IM-5 zeolite(lifetime of 3 h).The yield of propylene increases while ethylene decreases along with the increasing of n(Al2O3)/n(SiO2).TEAOH-treated IM-5 zeolites exhibited far longer catalytic lifespan ranging from 19 h to 102 h.The yield of propylene remains stable,while the yield of ethylene gradually increases with the increase of TEAOH treatment time.

关 键 词：甲醇制丙烯 IM-5分子筛 酸性调变 碱处理 

分 类 号：TQ426.94[化学工程]