物理化学学报 >> 2013, Vol. 29 >> Issue (06): 1281-1288.doi: 10.3866/PKU.WHXB201304101

催化和表面科学 上一篇    下一篇

甲醇芳构化中催化剂酸性对脱烷基、烷基化和异构化反应的影响

张金贵1, 骞伟中1, 汤效平1,2, 沈葵1, 王彤1,2, 黄晓凡2, 魏飞1   

  1. 1. 北京市绿色反应工程与工艺重点实验室, 清华大学化工系, 北京, 100084;
    2. 华电煤业集团有限公司煤化工事业部, 北京, 100031
  • 收稿日期:2013-01-16 修回日期:2013-04-09 发布日期:2013-05-17
  • 通讯作者: 骞伟中 E-mail:qianwz@mail.tsinghua.edu.cn
  • 基金资助:

    国家高技术研究发展计划(863)(2012AA051003)资助项目

Influence of Catalyst Acidity on Dealkylation, Isomerization and Alkylation in MTA Process

ZHANG Jin-Gui1, QIAN Wei-Zhong1, TANG Xiao-Ping1,2, SHEN Kui1, WANG Tong1,2, HUANG Xiao-Fan2, WEI Fei1   

  1. 1 Beijing Key Laboratory of Green Reaction Engineering & Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, P. R. China;
    2 Huadian Coal Industry Group Co. Ltd., Beijing, 100031, P. R. China
  • Received:2013-01-16 Revised:2013-04-09 Published:2013-05-17
  • Supported by:

    The project was supported by the National High Technology Research and Development Program of China (863) (2012AA051003).

摘要:

在Zn/P/ZSM-5催化剂上研究了甲醇、二甲苯、甲苯和甲醇等不同进料下芳烃产品分布随反应积碳的变化, 发现催化剂积碳对芳构化反应、脱烷基反应和烷基化反应的影响不同. 在不同硅铝摩尔比(Si/Al 比)和Zn负载量的Zn/P/ZSM-5 催化剂上进行甲醇转化, 考察催化剂酸性位点强度、密度和类型与芳烃收率和产品分布之间的关系, 发现当强酸位点酸密度下降时, 脱烷基反应最先被抑制, 其次是芳构化反应和异构化反应, 而烷基化反应却不受影响. 在Si/Al 比为14, 3% (w) Zn 负载量的Zn/P/ZSM-5 催化剂上可得到75%左右的芳烃收率, 二甲苯收率在35%左右, 具有重要的工业应用前景.

关键词: 甲醇, ZSM-5分子筛, 芳构化, 脱烷基, 烷基化, 异构化

Abstract:

Relationship between aromatics distribution, in the process of methanol to aromatics (MTA), and the conversion of methanol and the catalyst acidity was investigated over a series of Zn/P/ZSM-5 catalysts with different Si/Al molar ratios and zinc loading. To understand the contribution of aromatization, isomerization, dealkylation and alkylation reactivity of the catalyst to the aromatics distribution, coke deposition degree of Zn/P/ZSM-5 catalyst was tailored as using different feedstocks including methanol, xylene or the mixture of methanol and toluene. With the coke deposition, the amount of different types of acidic sites of catalyst varied significantly, characterized by NH3-temperature programmed desorption (NH3-TPD) and pyridine-infrared methods. Aromatization, dealkylation, alkylation, and isomerization showed sensitivity to a reduction in the density of strongly acidic sites. Dealkylation reaction was preferentially inhibited just by slightly decreasing the density of strong acid sites. However, aromatization and isomerization reaction were inhibited only when the density of strong acid sites was significantly decreased. In all cases, alkylation was found to be uninfluenced by acidic site density. A Zn/P/ZSM-5 catalyst with Si/Al molar ratio of 14 and 3% (w) Zn loading exhibited aromatics yields of 75% and xylene yields of about 35%, indicating potential for industrial application.

Key words: Methanol, ZSM-5 zeolite, Aromatization, Dealkylation, Alkylation, Isomerization

MSC2000: 

  • O643