催化学报

催化学报 ›› 2009, Vol. 30 ›› Issue (10): 1049-1057.

• 研究论文 • 上一篇    下一篇

不同结构SAPO-34催化剂上1-己烯催化裂解制丙烯

Zeeshan NAWAZ1, 汤效平 1, 朱杰 1, 魏飞 1,*, Shahid NAVEED2   

  1. 1 清华大学化工系北京市绿色反应工程与工艺实验室, 北京 100084 2 拉合尔大学化学工程系, 拉合尔 54890, 巴基斯坦
  • 收稿日期:2009-10-25 出版日期:2009-10-25 发布日期:2013-06-06

Catalytic Cracking of 1-Hexene to Propylene Using SAPO-34 Catalysts with Different Bulk Topologies

Zeeshan NAWAZ1, TANG Xiaoping1, ZHU Jie1, WEI Fei1,*, Shahid NAVEED2   

  1. 1Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua Univer-sity, Beijing 100084, China 2Department of Chemical Engineering, University of Engineering and Technology Lahore, Lahore 54890, Paki-stan
  • Received:2009-10-25 Online:2009-10-25 Published:2013-06-06

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1128

被引次数

31

摘要： 制备了 100% SAPO-34, 30% SAPO-34 和介孔-SAPO-34 三种不同类型的 SAPO-34 分子筛催化剂, 并采用氮吸附、扫描电镜、X 射线衍射和红外光谱等方法对催化剂进行了表征. 三种催化剂的微孔结构、比表面积和总酸量近似, 但具有不同的催化剂组成和次级结构. 以 1-己烯裂解为模型反应考察了三种催化剂的催化活性. 对于 30% SAPO-34 催化剂, 由于添加了粘结剂, 其外表面酸性和扩散性能下降, 导致催化活性降低; 100% SAPO-34 催化剂则具有较好的催化性能; 介孔 SAPO-34 催化剂次级结构的存在使其失活较慢, 从而提高了原料的转化率. 详细讨论了 1-己烯催化裂解制丙烯的活性和选择性曲线, 以进一步说明催化剂组成和结构的影响.

关键词: 1-己烯, 催化裂解, 丙烯, 扩散, SAPO-34

Abstract: Three SAPO-34 catalysts, 100% SAPO-34, 30% SAPO-34, and meso-SAPO-34, with different bulk topologies were prepared. The catalysts were characterized by N2 adsorption, scanning electron microscopy, X-ray diffraction, and infrared spectroscopy techniques. The pore size, total acidity, and internal cage structure of the catalysts were almost identical, but they had different bulk appearances. The role of the bulk topology/structure of the catalysts was studied using 1-hexene cracking. On 30% SAPO-34, the surface acidity and diffusion rate decreased due to blocking by binder, which adversely affected catalytic activity. 100% SAPO-34 gave better cracking ability and higher propylene selectivity because of suitable acid sites and effective shape selectivity, respectively. In order to study the effect of diffusion, meso-SAPO-34 was used. The different bulk structure gave different feed conversion and selectivity profiles. A superior control of the stereochemistry was observed in the cracking by the meso-SAPO-34 and 100% SAPO-34 catalysts, in which enhanced diffusion mass transport played an appreciable role. Most of the propylene was produced by the direct cracking pathway by the β-scission carbenium ion mechanism. Hydrogen transfer reactions became significant at higher conversions. Decreasing the residence time to a certain extend is an appropriate way to obtain high propylene yield and selectivity. Activity and selectivity patterns for 1-hexene cracking to propylene were compared to justify superior SAPO-34 topology for 1-hexene cracking to propylene.

Key words: 1-hexene, catalytic cracking, propylene, diffusion, SAPO-34