SCI和EI收录∣中国化工学会会刊

中国化学工程学报 ›› 2021, Vol. 38 ›› Issue (10): 276-285.DOI: 10.1016/j.cjche.2021.04.015

• Materials and Product Engineering • 上一篇    下一篇

Controllably tailoring external surface sites of nanosheet HZSM-5 for maximizing light olefins in catalytic cracking of n-decane

Tiantian Zhu1, Hairui Liang1, Bofeng Zhang1, Yajie Tian2, Guozhu Liu1   

  1. 1. Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China;
    2. Henan Province Engineering Research Center of Catalytic Reaction, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China
  • 收稿日期:2021-02-10 修回日期:2021-04-04 出版日期:2021-10-28 发布日期:2021-12-02
  • 通讯作者: Yajie Tian, Guozhu Liu
  • 基金资助:
    Financial supports by the National Natural Science Foundation of China (21776210 and 22008055) are gratefully acknowledged.

Controllably tailoring external surface sites of nanosheet HZSM-5 for maximizing light olefins in catalytic cracking of n-decane

Tiantian Zhu1, Hairui Liang1, Bofeng Zhang1, Yajie Tian2, Guozhu Liu1   

  1. 1. Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China;
    2. Henan Province Engineering Research Center of Catalytic Reaction, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China
  • Received:2021-02-10 Revised:2021-04-04 Online:2021-10-28 Published:2021-12-02
  • Contact: Yajie Tian, Guozhu Liu
  • Supported by:
    Financial supports by the National Natural Science Foundation of China (21776210 and 22008055) are gratefully acknowledged.

摘要: A series of triphenylethoxysilane (TPEOS)-modified nanosheet HZSM-5 catalysts (ZN-x, x = 4%, 8% and 16%, mass) were synthesized by chemical liquid deposition to selectively change external acidity distributions. TPEOS modification was found to passivate some external Brønsted and Lewis acid sites by 37.8%, in which Brønsted acid sites (BAS) were found more easily sacrificed by breaking the surface AlO bond of bridging hydroxyl groups and forming SiOSi bonds. The selectivity of ZN-8 catalyst for light olefins (ethylene, propylene and butene) in n-decane catalytic cracking is up to 26% (450 ℃, WHSV = 10.95 h-1), which is ca. 78% higher than that of parent one. The better performance was attributed to the appropriate external acid density in ZN-8, which inhibits bimolecular hydrogen transfer reaction of light olefins on the adjacent acid sites, resulting in more olefins, few coke precursors and thus an excellent catalytic stability.

关键词: Nanosheet HZSM-5, Acid properties, Surface modification, Catalysis, Deactivation, Fixed-bed

Abstract: A series of triphenylethoxysilane (TPEOS)-modified nanosheet HZSM-5 catalysts (ZN-x, x = 4%, 8% and 16%, mass) were synthesized by chemical liquid deposition to selectively change external acidity distributions. TPEOS modification was found to passivate some external Brønsted and Lewis acid sites by 37.8%, in which Brønsted acid sites (BAS) were found more easily sacrificed by breaking the surface AlO bond of bridging hydroxyl groups and forming SiOSi bonds. The selectivity of ZN-8 catalyst for light olefins (ethylene, propylene and butene) in n-decane catalytic cracking is up to 26% (450 ℃, WHSV = 10.95 h-1), which is ca. 78% higher than that of parent one. The better performance was attributed to the appropriate external acid density in ZN-8, which inhibits bimolecular hydrogen transfer reaction of light olefins on the adjacent acid sites, resulting in more olefins, few coke precursors and thus an excellent catalytic stability.

Key words: Nanosheet HZSM-5, Acid properties, Surface modification, Catalysis, Deactivation, Fixed-bed