化工学报 ›› 2016, Vol. 67 ›› Issue (8): 3400-3407.DOI: 10.11949/j.issn.0438-1157.20160459

• 催化、动力学与反应器 • 上一篇    下一篇

Cr掺杂ZSM-5双功能催化剂的制备及其催化裂解正丁烷

赵丹, 袁美华, 张耀远, 姜桂元, 赵震, 刘佳, 韩善磊, 孙华倩   

  1. 中国石油大学重质油国家重点实验室, 北京 102249
  • 收稿日期:2016-04-08 修回日期:2016-06-02 出版日期:2016-08-05 发布日期:2016-08-05
  • 通讯作者: 姜桂元
  • 基金资助:

    国家重点基础研究发展计划项目(2012CB215001);国家自然科学基金石油化工联合基金项目(U1162117);北京高等学校青年英才计划项目(YETP0696);教育部新世纪优秀人才计划项目(NCET-11-0732);中国石油大学(北京)前瞻导向项目(QZDX-2014-02)。

Incorporation of Cr in ZSM-5 zeolite framework as bifunctional catalysts for n-butane catalytic cracking

ZHAO Dan, YUAN Meihua, ZHANG Yaoyuan, JIANG Guiyuan, ZHAO Zhen, LIU Jia, HAN Shanlei, SUN Huaqian   

  1. State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China
  • Received:2016-04-08 Revised:2016-06-02 Online:2016-08-05 Published:2016-08-05
  • Supported by:

    supported by the National Basic Research Program of China (2012CB215001), the National Natural Science Foundation of China (U1162117), the Beijing Higher Education Young Elite Teacher Project (YETP0696), the Program for New Century Excellent Talents in University (NCET-11-0732) and the Prospect Oriented Foundation of China University of Petroleum, Beijing (QZDX-2014-02).

摘要:

采用原位合成的方法制备了Cr掺杂的ZSM-5分子筛,研究了Cr含量对于正丁烷催化裂解性能的影响。利用X射线衍射(XRD)、N2吸附脱附、紫外可见漫反射光谱(UV-Vis)、拉曼光谱(Raman)、氨程序升温脱附技术(NH3-TPD)和吡啶红外(Py-FTIR)等表征手段研究了分子筛的结构、Cr物种的存在状态以及分子筛的酸性。研究结果表明,部分Cr进入分子筛的骨架,以单分散的形式存在,当Cr含量较低时,Cr的引入对于分子筛的弱酸性没有太大的影响。少量Cr的引入会极大提高正丁烷的转化率和乙烯、丙烯的收率,当Cr/Al摩尔比为0.04,反应温度为650℃时,正丁烷的转化率达到99.2%,乙烯、丙烯的收率达到53.8%,分别比未改性的ZSM-5高15.5%和5.0%。这可能是由于Cr活性组分的脱氢性能和分子筛的酸性形成协同作用,促进了正丁烷的高效转化。

关键词: Cr掺杂, ZSM-5分子筛, 双功能, 催化裂解, 低碳烯烃

Abstract:

The Cr-doped ZSM-5 zeolites were synthesized by in-situ hydrothermal method and were used in studying Cr effect on catalytic cracking of n-butane to produce light olefins. Zeolite structure, chemical state of Cr species and acidity of zeolites were characterized by several techniques, including X-ray diffraction, nitrogen adsorption and desorption, ultraviolet visible diffuse reflectance spectroscopy, Raman spectroscopy, ammonia temperature-programmed desorption and pyrrolidine (Py)-FTIR. Cr species were found to partially incorporate in the ZSM-5 framework and present in the form of monodispersion. No significant difference in the weak acidity of zeolites at low Cr content. However, a small amount of Cr species in zeolites could significantly enhance conversion of n-butane and improve yield of ethylene and propylene. When the molar ratio of Cr/Al was 0.04, the conversion of n-butane was 99.6% and the yield of ethylene and propylene was 53.8% at reaction temperature of 650℃, which was 15.5% and 5.0% higher than those of unmodified ZSM-5, respectively. The superior catalytic performance could be attributed to synergistic effects of dehydrogenation of active Cr species and cracking function of the acidic zeolite, which promoted highly efficient conversion of n-butane.

Key words: Cr doping, ZSM-5 zeolites, bifunctionality, catalytic cracking, light olefins

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