催化学报

催化学报 ›› 2007, Vol. 28 ›› Issue (9): 766-772.

• 研究论文 • 上一篇    下一篇

浸渍钠对铁基催化剂F-T合成浆态床反应性能的影响

安霞1,2,吴宝山1,万海军1,2,李廷真1,2,陶智超1,2,相宏伟1,李永旺1   

  1. 1 中国科学院山西煤炭化学研究所煤转化国家重点实验室, 山西太原 030001; 2 中国科学院研究生院, 北京 100049
  • 收稿日期:2007-09-25 出版日期:2007-09-25 发布日期:2011-09-28

Effect of Na Addition on Iron-Based Catalyst for Fischer-Tropsch Synthesis

AN Xia1,2, WU Baoshan1*, WAN Haijun1,2, LI Tingzhen1,2, TAO Zhichao1,2, XIANG Hongwei1, LI Yongwang1   

  1. 1 State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, The Chinese Academy of Sciences, Taiyuan 030001, Shanxi, China; 2 Graduate University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2007-09-25 Online:2007-09-25 Published:2011-09-28

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摘要： 以FeCuK/SiO2为母体催化剂,通过乙酸钠浸渍得到一组不同Na含量的费托合成铁基催化剂. 采用原子发射光谱、低温N2吸附、程序升温还原和Mssbauer谱等技术对催化剂进行了表征. 在H2/CO摩尔比为0.67, 空速为2000h-1, 压力为1.5 MPa和温度为250 ℃的条件下进行了浆态床F-T合成反应性能评价实验. 结果表明,浸渍少量Na能提高催化剂的比表面积,促进铁物相的分散,而浸渍大量Na却大大降低了催化剂的比表面积,使催化剂中的铁物相聚集形成较大的颗粒; 浸渍Na抑制了催化剂在H2中的第一步还原,但促进了催化剂在CO中的碳化; 在原位合成气还原过程中,浸渍Na有利于催化剂的碳化. 在500 h的运行实验中,浸渍Na的催化剂均表现出不同程度的失活现象. 反应结果表明,浸渍Na对水煤气变换反应活性影响不大,对费托合成反应活性和烃产物选择性有较大的影响. 在铁基催化剂上浸渍Na有利于C12+重质烃和低碳烯烃的生成.

关键词: 钠, 费托合成, 铁基催化剂, 浆态床反应器

Abstract: A series of Fe-based catalysts for Fischer-Tropsch synthesis (FTS) were prepared by impregnation of the FeCuK/SiO2 precursor with different amounts of sodium acetate. The catalysts were characterized by atomic emission spectroscopy, N2 adsorption, temperature-programmed reduction, and Mssbauer effect spectroscopy. The catalytic performance for FTS was investigated in a continuous stirred tank slurry reactor under reaction conditions of H2/CO=0.67, WHSV=2000h-1, 1.5 MPa, and 250 ℃. A low level of Na loading increases the surface area of the catalyst and enhances the dispersion of iron species in the catalyst, but excessive addition of Na decreases the surface area. Incorporation of Na in the catalyst inhibits the first step reduction in H2 and promotes carburization in CO or syngas. The catalysts with different Na loadings display various FTS activity and are deactivated after 500 h on stream to some extent. Moreover, the reaction results indicate that the addition of Na slightly affects water-gas shift activity, suppresses methane selectivity, and promotes light alkene selectivity.

Key words: sodium, Fischer-Tropsch synthesis, iron-based catalyst, slurry reactor