Abstract:

The paper introduces the mechanism of coke deposition over SAPO-34 molecular sieve catalyst used for methanol to olefins reaction，and the effect of catalyst physicochemical characteristics and reaction process condition on coking behavior. The researches on kinetics of coke formation and coke combustion are outlined. Coke species formed on SAPO-34 are mainly polyaromatic species，such as anthracene，phenanthrene and pyrene. The deactivation rate can be attenuated when acidity density and size of molecular sieve are decreased properly. Carbon deposition exponentially increases when reaction temperature increases. Rapid carbon formation is observed in the initial phase of reaction and then rate of carbon deposition decreases. Coke deposition decreases as the ratio of catalyst to methanol increases. Coke formation can be decreased by the presence of water in the feed，but the effect of water weakens gradually with the progress of the reaction. Coke combustion rate is directly proportional to oxygen pressure and coke amount. The review provides reference for improving catalyst performance，prolonging catalyst life time and improving olefins selectivity to optimize the reaction and regeneration process condition.

摘要：

介绍了SAPO-34分子筛催化甲醇制烯烃反应时催化剂的积炭机理，催化剂物化性能、反应工艺条件对催化剂积炭行为的影响，积炭和烧炭动力学研究成果。总结显示，导致SAPO-34失活的积炭物种为蒽、菲、芘等稠环芳烃。适当降低分子筛酸密度、减小粒径，可减缓积炭失活速率。随着反应温度升高，催化剂积炭量呈指数规律增长，反应初始阶段的积碳生成速率很快，随后趋于平缓；增加剂醇比，催化剂上积炭量降低；增加原料中水含量，反应初期催化剂积炭量明显降低，但随着反应进行，水的效果逐渐减弱。积炭燃烧速率与氧气分压、催化剂积炭量成正比。对甲醇制烯烃反应过程中催化剂上的积炭问题进行系统分析，为确定催化剂改进方向，延长催化剂寿命、提高低碳烯烃选择性而合理控制反应和再生工艺条件提供依据。