甲苯歧化反应中ZSM-5沸石催化剂积碳规律的研究

采用积分反应器研究了甲苯非临氢歧化反应中ZSM-5沸石催化剂的积碳规律,得到了积碳速率与反应时间的关联式,并考察了不同反应参数对积碳的影响。结果表明,随着歧化反应的进行,积碳量逐渐增加,而积碳速率逐渐下降;提高反应温度及使用低硅铝比的沸石催化剂,均导致积碳及失活速率加快;在实验范围内,空速及催化剂颗粒度对积碳过程无显著影响。此外,反应初期催化剂上的少量积碳有利于甲苯歧化反应,但积碳量达到一定程度后,甲苯转化率及二甲苯收率均显著下降。

Study of Coke Formation on ZSM - 5 Zeolite during Toluene Disproportionation Process

Coke formation of ZSM-5 zeolite during toluene disproportionation process was investigated in an integral reactor.Rate of coke formation was correlated with reaction time.Influences of reaction parameters on coke formation had been examined.Rate of coke formation decreased with reaction time,while amount of coke formed increased.Higher temperature and ZSM-5 zeolite with lower silicon-to-aluminium ratio led to more rapid coke formation.Under conditions of this study,space velocity and granule size of ZSM-5 zeolite had no significant influence on coke formation.In early stage of reaction,coke formation was advantageous to toluene disproportionation process.However,when coke built up,toluene conversion and xylene yield fell remarkably.