甲醇制烯烃反应过程中SAPO-34催化剂积炭动力学研究

在固定床反应器中研究了甲醇制烯烃反应过程中SAPO-34分子筛催化剂的积炭动力学，分别得到了催化剂积炭量与反应温度、剂醇比的经验关联式。结果表明，催化剂床层存在明显的积炭分布，在450 ℃，甲醇WHSV为15 h－1，催化剂积炭量随催化剂反应运行时间（Time on Stream, TOS）为25 min时，床层入口处的积炭量平均为9.56%，而出口处的积炭量平均为3.20%，属于平行失活，积炭主要来源于甲醇生成的高碳中间体，这些中间体在生成低碳烃的同时生成积炭。从积炭的生成机理出发，得到了SAPO-34分子筛催化剂的积炭动力学机理模型，将催化剂积炭量与一定催化剂停留时间内反应过程中甲醇的转化量相关联，该模型形式同样简单，能够较好地拟合实验数据。

Kinetic modeling of coke formation on SAPO-34 catalyst in the transformation of methanol to olefins

The kinetics of coke formation on SAPO-34 catalyst in the transformation of methanol to olefins was studied in a fixed bed reactor and the relations in a type of Voorhies equation between coke deposition and reaction temperature or the ratio of catalyst-to-methanol were obtained, which could be used easily in practice. In the condition of 450 ℃, 15 h－1 methanol WHSV and 25 min TOS, an obvious coke distribution was found in the catalyst bed with a coke content of 9.56% at the inlet of catalyst bed and 3.20% at the outlet, which corresponded to a deactivation mainly in parallel with the main reaction. The coke was formed mainly in parallel with the formation of hydrocarbons, and all the products came from intermediates generated from methanol. On the basis of this mechanism, a kinetic model for coke formation which related the coke deposition with the methanol converted in reaction was induced. This kinetic model showed a good agreement with the experimental observation and also could be used easily.