SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2022, Vol. 45 ›› Issue (5): 203-210.DOI: 10.1016/j.cjche.2021.05.028

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Efficient conversion of benzene and syngas to toluene and xylene over ZnO-ZrO2&H-ZSM-5 bifunctional catalysts

Xiao Zhao1, Xuan Shi1, Zhongshun Chen1, Long Xu1,2, Chengyi Dai1,2, Yazhou Zhang1, Xinwen Guo3, Dongyuan Yang4,5, Xiaoxun Ma1,2   

  1. 1 School of Chemical Engineering, Northwest University, Xi'an 710069, China;
    2 International Science & Technology Cooperation Base for Clean Utilization of Hydrocarbon Resources, Chemical Engineering Research Center of the Ministry of Education for Advanced Use Technology of Shanbei Energy, Collaborative Innovation Center for Development of Energy and Chemical Industry in Northern Shaanxi, Northwest University, Xi'an 710069, China;
    3 School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China;
    4 Shaanxi Key Laboratory of Energy Chemical Process Intensification, School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an 710049, China;
    5 Shanxi yanchang, Petroleum (Group) Corp. Ltd, Xi'an 710000, China
  • Received:2021-02-03 Revised:2021-05-01 Online:2022-06-22 Published:2022-05-28
  • Contact: Chengyi Dai,E-mail:daicy@nwu.edu.cn;Dongyuan Yang,E-mail:yangdongyuan885@163.com;Xiaoxun Ma,E-mail:maxym@nwu.edu.cn
  • Supported by:
    The authors thank the financial support from the National Key Research & Development Program of China (2018YFB0604901), the National Natural Science Foundation of China (21706210) and the Key Research & Development Program of Shaanxi Province (2020ZDLGY11-06).

Efficient conversion of benzene and syngas to toluene and xylene over ZnO-ZrO2&H-ZSM-5 bifunctional catalysts

Xiao Zhao1, Xuan Shi1, Zhongshun Chen1, Long Xu1,2, Chengyi Dai1,2, Yazhou Zhang1, Xinwen Guo3, Dongyuan Yang4,5, Xiaoxun Ma1,2   

  1. 1 School of Chemical Engineering, Northwest University, Xi'an 710069, China;
    2 International Science & Technology Cooperation Base for Clean Utilization of Hydrocarbon Resources, Chemical Engineering Research Center of the Ministry of Education for Advanced Use Technology of Shanbei Energy, Collaborative Innovation Center for Development of Energy and Chemical Industry in Northern Shaanxi, Northwest University, Xi'an 710069, China;
    3 School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China;
    4 Shaanxi Key Laboratory of Energy Chemical Process Intensification, School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an 710049, China;
    5 Shanxi yanchang, Petroleum (Group) Corp. Ltd, Xi'an 710000, China
  • 通讯作者: Chengyi Dai,E-mail:daicy@nwu.edu.cn;Dongyuan Yang,E-mail:yangdongyuan885@163.com;Xiaoxun Ma,E-mail:maxym@nwu.edu.cn
  • 基金资助:
    The authors thank the financial support from the National Key Research & Development Program of China (2018YFB0604901), the National Natural Science Foundation of China (21706210) and the Key Research & Development Program of Shaanxi Province (2020ZDLGY11-06).

Abstract: A series of ZnO-ZrO2 solid solutions with different Zn contents were synthesized by the urea co-precipitation method, which were coupled with H-ZSM-5 zeolite to form bifunctional catalysts. As a new benzene alkylation reagent, syngas was used instead of methanol to realize the efficient conversion of syngas and benzene into toluene and xylene. A suitable ratio of ZnO-ZrO2 led to the significant improvement in the catalytic performance, and a suitable amount of acid helped to increase the selectivity of toluene/xylene and reduce the selectivity of the by-products ethylbenzene and C9+ aromatics. The highest benzene conversion of 89.2% and toluene/xylene selectivity of 88.7% were achieved over 10% ZnO-ZrO2&H-ZSM-5 (Si/Al = 23) at a pressure of 3 MPa and a temperature of 450 ℃. In addition, the effect of the zeolite framework structure on product distribution was examined. Similar to the molecular dynamics of aromatic hydrocarbons, H-ZSM-5 zeolites comprise 10-membered-ring pores, which are beneficial to the activation of benzene; hence, the conversion of benzene is higher. H-ZSM-35 and H-MOR zeolites exhibited small eight-membered-ring channels, which were not conducive to the passage of benzene; hence, the by-product ethylbenzene exhibits a higher selectivity. The distance between the active centers of the bifunctional catalysts was the main factor affecting the catalytic performance, and the powder mixing method was more conducive to the conversion of syngas and benzene.

Key words: ZnO-ZrO2, Bifunctional catalysts, Aromatics, Alkylation of benzene, Syngas

摘要: A series of ZnO-ZrO2 solid solutions with different Zn contents were synthesized by the urea co-precipitation method, which were coupled with H-ZSM-5 zeolite to form bifunctional catalysts. As a new benzene alkylation reagent, syngas was used instead of methanol to realize the efficient conversion of syngas and benzene into toluene and xylene. A suitable ratio of ZnO-ZrO2 led to the significant improvement in the catalytic performance, and a suitable amount of acid helped to increase the selectivity of toluene/xylene and reduce the selectivity of the by-products ethylbenzene and C9+ aromatics. The highest benzene conversion of 89.2% and toluene/xylene selectivity of 88.7% were achieved over 10% ZnO-ZrO2&H-ZSM-5 (Si/Al = 23) at a pressure of 3 MPa and a temperature of 450 ℃. In addition, the effect of the zeolite framework structure on product distribution was examined. Similar to the molecular dynamics of aromatic hydrocarbons, H-ZSM-5 zeolites comprise 10-membered-ring pores, which are beneficial to the activation of benzene; hence, the conversion of benzene is higher. H-ZSM-35 and H-MOR zeolites exhibited small eight-membered-ring channels, which were not conducive to the passage of benzene; hence, the by-product ethylbenzene exhibits a higher selectivity. The distance between the active centers of the bifunctional catalysts was the main factor affecting the catalytic performance, and the powder mixing method was more conducive to the conversion of syngas and benzene.

关键词: ZnO-ZrO2, Bifunctional catalysts, Aromatics, Alkylation of benzene, Syngas