Acta Chimica Sinica ›› 2023, Vol. 81 ›› Issue (1): 14-19.DOI: 10.6023/A22070329 Previous Articles     Next Articles

Article

Fe@Si/S-34催化剂的制备及其合成气制烯烃性能

陈治平a,b,*(), 孟永乐a, 芦静a, 周文武a,b,*(), 杨志远a,b, 周安宁a,b   

  1. a 西安科技大学 化学与化工学院 西安 710054
    b 西部煤炭绿色安全开发国家重点实验室(筹) 西安 710054
  • 投稿日期:2022-07-23 发布日期:2022-12-19
  • 基金资助:
    国家自然科学基金(21908174); 国家自然科学基金(22178283); 陕西省自然科学基础研究计划面上项目(2020JM-517); 西安科技大学2021年度优秀青年科学基金资助

Preparation of Fe@Si/S-34 Catalysts and Its Catalytic Performance for Syngas to Olefins

Zhiping Chena,b(), Yongle Menga, Jing Lua, Wenwu Zhoua,b(), Zhiyuan Yanga,b, Anning Zhoua,b   

  1. a College of Chemistry and Chemcial Engineering, Xi'an University of Science and Technology, Xi'an 710054, China
    b The State Key Laboratory of Green and Safe Coal Development in Western China, Xi'an 710054, China
  • Received:2022-07-23 Published:2022-12-19
  • Contact: *E-mail: cupczp@163.com; Zhww1015@163.com; Tel: 029-85583183
  • Supported by:
    National Natural Science Foundation of China(21908174); National Natural Science Foundation of China(22178283); Natural Science Basic Research Plan in Shaanxi Province of China(2020JM-517); Excellent Youth Science Foundation in Xi'an University of Science and Technology(2021)

The direct synthesis of light olefins from syngas via Fischer-Tropsch synthesis reaction is a promising technology for direct synthesis of olefins from syngas. The key is to improve the selectivity of light olefins through the regulation of product distribution. In this work, the hydrophobic Fe@Si catalyst was prepared by room temperature solid state method- Stöber-silylation method, and then the catalyst was combined with SAPO-34 molecular sieves with different contents to prepare Fe@Si/S-34 composite catalysts. The effects of SAPO-34 molecular sieve content on the physicochemical properties of the catalysts were investigated by X-ray diffraction, scanning electron microscopy, N2 adsorption-desorption, NH3 temperature programmed desorption and water contact angle measurement. The results showed that the content of SAPO-34 molecular sieve has significant influence on the surface area, pore volume, acidity and hydrophobicity of the catalysts. With the increase of SAPO-34 molecular sieve content, the specific surface area and total pore volume of the catalyst increased, the weak acid and medium-strong acid sites increased, and the hydrophobicity weakened. The catalytic performance evaluation results showed that the Fe@Si/S-34 composite catalyst decomposed C5+ hydrocarbons into light hydrocarbons, significantly reduced the selectivity of C5+ products and increased the selectivity of C2~C4 hydrocarbons. Appropriate SAPO-34 molecular sieve could significantly improve the selectivity of C2~C4 olefins. When the mass ratio of Fe@Si catalyst to SAPO-34 is 2, the C2~C4 olefin selectivity of Fe@Si/S-34 catalyst is the highest, the conversion of CO is 80.0%, the selectivity of CO2 in the product is 8.9%, and the selectivity of C2~C4 olefins is 31.1%. In this study, the hydrophobicity of Fe@Si catalyst and the cracking activity of SAPO-34 molecular sieve for C5+ hydrocarbon were coupled together to inhibit the water-gas shift (WGS) reaction, reduce the CO2 selectivity and obtain higher C2~C4 olefin selectivity, which provided a new strategy for the development of catalysts for Fischer-Tropsch synthesis to olefins.

Key words: syngas, light olefins, Fischer-Tropsch synthesis, hydrophobic catalyst, SAPO-34 molecular sieve