Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (09): 2122-2128.doi: 10.3866/PKU.WHXB201206211

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Size Effect of HZSM-5 Zeolite on Catalytic Conversion of Methanol to Propylene

YAO Min1,2, HU Si3, WANG Jian2, DOU Tao3, WU Yong-Ping1   

  1. 1. School of Energy Engineering, Xi?an University of Science and Technology, Xi?an 710054, P. R. China;
    2. Shen Hua Ningxia Coal Industry Group Co., Ltd., Yinchuan 750011, P. R. China;
    3. The Key Laboratory of Catalysis, China National Petroleum Corporation, China University of Petroleum, Beijing 102249, P. R. China
  • Received:2012-04-20 Revised:2012-06-20 Published:2012-08-02
  • Contact: WU Yong-Ping E-mail:wuyp@xust.edu.cn
  • Supported by:

    The project was supported by the National Key Technologies R & D Program of China (2007BAA08B05).

Abstract:

Catalytic conversion of methanol to propylene (MTP) by HZSM-5 zeolite is of great importance in industrial applications. In this paper, a series of HZSM-5 zeolites with different crystal sizes were synthesized by adjusting the initial gel composition, crystallization temperature, and crystallization time. The crystal structure, size, morphology, pore structure, and acidity of HZSM-5 were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption, and temperature-programmed desorption of ammonia (NH3-TPD). The catalytic activity and stability of HZSM-5 with different crystal sizes for MTP were evaluated on a continuous flowing fixed-bed reactor. Coke deposited on HZSM-5 was analyzed by thermogravimetric (TG) analyzer. Results indicated that with smaller crystal size, HZSM-5 zeolite had larger surface area and pore volume, higher density of pore openings, and shorter path length of micropore channels that prevent side reactions. For MTP reaction, smaller crystal sizes of HZSM-5 showed a higher resistance and better tolerance to coke, and longer catalytic lifetime. The lowering of both the total and strong acidity on HZSM-5 with smaller crystal size favored a higher selectivity of target product, propylene.

Key words: HZSM-5 zeolite, Crystal size, Methanol, Propylene, Acid property, Coke deposition

MSC2000: 

  • O643