水热处理ZSM-5沸石对乙苯转化型二甲苯异构化催化剂性能的影响

对ZSM-5沸石进行水热处理,将其按一定比例与丝光沸石复配制备了乙苯转化型二甲苯异构化催化剂(简称MZ催化剂);在连续流动固定床反应器中评价了MZ催化剂的异构化性能;考察了ZSM-5沸石的水热处理温度、处理时间和水蒸气用量对MZ催化剂异构化性能的影响。实验结果表明,较适宜的水热处理条件为:温度450～500℃,时间4～6 h,水蒸气用量18～36 g/h。在该条件下水热处理的ZSM-5沸石制备的MZ催化剂,在反应温度370℃、压力0.60 MPa、重时空速3.5 h~(-1)、n(H_2):n(原料油)为5.0的反应条件下,异构化活性达23%以上,乙苯转化率保持在38%左右,C_8芳烃收率在96%以上。

Effect of Hydrothermal Treatment of ZSM-5 Zeolite on Performance of Xylene Isomerization Catalyst with Feature of Ethylbenzene Conversion

Xylene isomerization catalysts with feature of ethylbenzene conversion were prepared from mordenite and ZSM-5 zeolite according to a suitable ratio.The ZSM-5 zeolite was treated by high temperature steam in advance.The activity and selectivity of catalysts were studied in a continuous fixed bed down-flow reactor.Effects of steam treating temperature,time and steam flowrate on performance of the catalyst in xylene isomerization were investigated.Optimal treating conditions were: temperature 450-500 ℃,time 4-6 h and steam flowrate 18-36 g/h.Under optimal reaction conditions:370 ℃,0.60 MPa,WHSV 3.5 h~(-1),n(H_2):n(feed oil) 5.0,isomerization activity of the above catalyst was more than 23%,conversion of ethylbenzene was about 38% and yield of C_8 aromatics was more than 96%.