【摘要】 高温一般有利于甲醇转化为低碳烯烃,但在此条件下,通常的五元环高硅沸石的活性也会随在线反应时间的处长而逐渐衰减。失活包括可逆和不可逆两部分,前者是由于催化剂结炭,后是由于水热效应导致酸性中心的减少。针对上述原因,本文研制出稳定性相当高的催化剂,可以经历83次的氧化再生,在线反应时间超过1000小时,C₂—C₄烯烃和乙烯平均选择性分别为89.7和31.5%。更多还原

【Abstract】 The conversion of methanol to olefins is considered more favorable at higher temperature both in view of thermodynamics and kinetics. But at high temperature such as 550℃, the activity of zeolite of pentasil type even with moderate Si/Al ratio would be subjected to gradual deterioration with the increasing of time on stream. The initial symptomatic implication of aging was reflected on the variation of hydrocarbon distribution, while the conversion of oxygenates, yields of hydro-carbons and lower olefins still held almost, unchanged. The most sensitive criterion for deactivation was the declination of ethene. Aging comprises the reversible type attributable to the coke superimposing on the acidic sites, and the irreversible one to the diminution of the number of acidic sites duc to dealumination, as having been confirmed by analysis of the aged catalyst. By taking appropriate measures, Zeolite catalysts capable of sustaining 83 regenerations with on stream time over 1000 hours were successfully prepared, and the yields of C2-C4 olefins and ethene averaged were over 89 and 31% respectively. This result has been verified in a bench scale test with whole pellet catalyst.更多还原