Ni-MgO复合改性对HZSM-5分子筛催化性能的影响

THE EFFECT OF Ni-MgO COMPOSITE MODIFICATION ON THE CATALYTIC PERFORMANCE OF HZSM-5 MOLECULAR SIEVE

采用等体积浸渍法制备了Ni和MgO改性的HZSM-5催化剂,考察Ni和MgO含量对甲醇制备丙烯的影响,并利用XRD、SEM、BET、NH 3-TPD等方法考察了Ni和MgO对HZSM-5分子筛的酸强度和结构的影响,结果表明,少量的Ni-Mg复合改性的HZSM-5分子筛MFI结构没有改变,但有效改变了催化剂的酸强度和孔径结构,显著降低催化剂中强酸含量,微孔孔径由0.5105 nm降为0.5016 nm,0.5%Ni-0.5%Mg/HZSM-5分子筛表现出较佳的丙烯选择性,丙烯的选择性提高了11.5%。

A series of Ni and MgO modified HZSM-5 catalysts were prepared by equal-volume impregnation method.The effects of Ni and MgO contents on the preparation of propylene from methanol were investigated.The influence of Ni and MgO on the acid strength and structure of HZSM-5 molecular sieve were studied through XRD,SEM,BET,NH 3-TPD and other testing methods.The results showed that the composite modification of HZSM-5 molecular sieve by Ni and MgO effectively changed the acid strength and pore structure of the catalyst,significantly reduced the content of strong acid in the catalyst,and reduced the pore size from 0.5105 nm to 0.5016 nm.The selectivity of propylene was increased by 11.5%,and the yield of ethylene,propylene and other by-products was greatly reduced.