SCI和EI收录∣中国化工学会会刊

中国化学工程学报 ›› 2024, Vol. 66 ›› Issue (2): 136-144.DOI: 10.1016/j.cjche.2023.10.004

• Full Length Article • 上一篇    下一篇

HZSM-5 zeolites undergoing the high-temperature process for boosting the bimolecular reaction in n-heptane catalytic cracking

Chenggong Song1, Zhenzhou Ma1, Xu Hou1, Hao Zhou1, Huimin Qiao1, Changchang Tian1, Li Yin1, Baitang Jin2, Enxian Yuan3   

  1. 1. School of Chemical Engineering, Changchun University of Technology, Changchun, 130012, China;
    2. Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27606, USA;
    3. School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, 225009, China
  • 收稿日期:2023-05-03 修回日期:2023-10-12 出版日期:2024-02-28 发布日期:2024-04-20
  • 通讯作者: Xu Hou,E-mail:houx@ccut.edu.cn;Enxian Yuan,E-mail:exyuan@yzu.edu.cn
  • 基金资助:
    The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China (21908010), Jilin Provincial Department of Science and Technology (20220101089JC) and the Education Department of Jilin Province (JJKH20220694KJ).

HZSM-5 zeolites undergoing the high-temperature process for boosting the bimolecular reaction in n-heptane catalytic cracking

Chenggong Song1, Zhenzhou Ma1, Xu Hou1, Hao Zhou1, Huimin Qiao1, Changchang Tian1, Li Yin1, Baitang Jin2, Enxian Yuan3   

  1. 1. School of Chemical Engineering, Changchun University of Technology, Changchun, 130012, China;
    2. Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27606, USA;
    3. School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, 225009, China
  • Received:2023-05-03 Revised:2023-10-12 Online:2024-02-28 Published:2024-04-20
  • Contact: Xu Hou,E-mail:houx@ccut.edu.cn;Enxian Yuan,E-mail:exyuan@yzu.edu.cn
  • Supported by:
    The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China (21908010), Jilin Provincial Department of Science and Technology (20220101089JC) and the Education Department of Jilin Province (JJKH20220694KJ).

摘要: High-temperature treatment is key to the preparation of zeolite catalysts. Herein, the effects of high-temperature treatment on the property and performance of HZSM-5 zeolites were studied in this work. X-Ray diffraction, N2 physisorption, 27Al magic angle spinning nuclear magnetic resonance (MAS NMR), and temperature-programmed desorption of ammonia results indicated that the high-temperature treatment at 650°C hardly affected the inherent crystal and texture of HZSM-5 zeolitesbut facilitated the conversion of framework Al to extra-framework Al, reducing the acid site and enhancing the acid strength. Moreover, the high-temperature treatment improved the performance of HZSM-5 zeolites in n-heptane catalytic cracking, promoting the conversion and light olefins yield while inhibiting coke formation. Based on the kinetic and mechanism analysis, the improvement of HZSM-5 performance caused by high-temperature treatment has been attributed to the formation of extra-framework Al, which enhanced the acid strength, facilitated the bimolecular reaction, and promoted the entropy change to overcome a higher energy barrier in n-heptane catalytic cracking.

关键词: HZSM-5, n-Heptane, Catalytic cracking, High-temperature treatment, Extra-framework Al

Abstract: High-temperature treatment is key to the preparation of zeolite catalysts. Herein, the effects of high-temperature treatment on the property and performance of HZSM-5 zeolites were studied in this work. X-Ray diffraction, N2 physisorption, 27Al magic angle spinning nuclear magnetic resonance (MAS NMR), and temperature-programmed desorption of ammonia results indicated that the high-temperature treatment at 650°C hardly affected the inherent crystal and texture of HZSM-5 zeolitesbut facilitated the conversion of framework Al to extra-framework Al, reducing the acid site and enhancing the acid strength. Moreover, the high-temperature treatment improved the performance of HZSM-5 zeolites in n-heptane catalytic cracking, promoting the conversion and light olefins yield while inhibiting coke formation. Based on the kinetic and mechanism analysis, the improvement of HZSM-5 performance caused by high-temperature treatment has been attributed to the formation of extra-framework Al, which enhanced the acid strength, facilitated the bimolecular reaction, and promoted the entropy change to overcome a higher energy barrier in n-heptane catalytic cracking.

Key words: HZSM-5, n-Heptane, Catalytic cracking, High-temperature treatment, Extra-framework Al