分子筛上甲醇转化过程的热力学和拓扑结构

doi:10.11949/j.issn.0438-1157.20171231

摘要/Abstract

摘要：

现代新型煤化工是我国当今基础有机化学工业发展的新亮点，也是世界化工界的又一次革命。煤制化学品路线经历气化、变换、甲醇合成、甲醇制烃类等过程，其中，最为重要的是分子筛上甲醇转化的过程。本文综述了分子筛上甲醇转化的相关研究，一方面从ZSM-5上甲醇转化的生成烃池及烯烃的热力学机制和产物分布出发，介绍了多甲基苯生成烯烃热力学平衡模型和其中的芳烃池生成烯烃热力学机制，另一方面，介绍了基于Ising模型的分子筛离散拓扑结构模型。利用分子筛孔道堵塞与围棋中“气”的有无的类似性，能够很好地再现SAPO-34上的相变失活现象和不均匀的积炭分布现象。以模型为指导，介绍了一些分子筛多级结构构筑的工作，这些工作很好地提升了催化剂选择性和寿命。这些概念对于准确理解甲醇在分子筛上的反应与失活机制、产品分布及提高选择性有指导意义。

关键词: 分子筛, 拓扑, 甲醇, 热力学, 模型

Abstract:

Novel modern coal chemical technology is not only a new sparkling spot in development of fundamental organic chemical industry in China, but also another revolution in chemical industry worldwide. Coal manufacturing processes for chemical products include gasification, water gas shift, methanol synthesis, and methanol conversion to hydrocarbon, which methanol conversion over zeolites plays a key role. Related researches on methanol conversion were reviewed in both thermodynamics and topological model. The thermodynamic equilibrium model for conversion of multimethylbenzene to olefins and thermodynamics mechanism of olefin formation were studied from thermodynamic mechanism and product distributions of hydrocarbons and olefins synthesized from methanol conversion over ZSM-5 catalyst. The zeolite topological structure model was based on discrete Ising model. Phase-transition phenomenon in SAPO-34 deactivation and non-uniform distribution of coke was explained from similarity between zeolite channel blockage and “liberty” in the game of Go. Guided by these models, work on designing hierarchical structures of zeolites were illustrated, which greatly enhanced selectivity and lifetime of catalysts. These concepts show their importance for accurately understanding mechanisms of methanol reaction on zeolites and zeolite deactivation, product distribution and enhancement of catalyst selectivity.

Key words: molecular sieves, topology, methanol, thermodynamics, model

中图分类号:

TQ032.4

蔡达理, 张晨曦, 侯一林, 陈兆辉, 王垚, 崔宇, 魏飞. 分子筛上甲醇转化过程的热力学和拓扑结构[J]. 化工学报, 2018, 69(1): 116-127.

CAI Dali, ZHANG Chenxi, HOU Yilin, CHEN Zhaohui, WANG Yao, CUI Yu, WEI Fei. Thermodynamics and topology in methanol conversion process over zeolites[J]. CIESC Journal, 2018, 69(1): 116-127.

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