催化学报

催化学报 ›› 2009, Vol. 30 ›› Issue (11): 1101-1108.

• 研究论文 • 上一篇    下一篇

焙烧温度对费托合成铁基催化剂还原动力学的影响

王洪1,2, 杨勇1, 吴宝山1, 许健1, 王虎林1,2, 定明月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:2009-11-25 出版日期:2009-11-25 发布日期:2013-07-17

Effect of Calcination Temperature on the Reduction Kinetics of Iron-Based Fischer-Tropsch Catalyst

WANG Hong1,2, YANG Yong1,*,WU Baoshan1, XU Jian1, WANG Hulin1,2, DING Mingyue1,2, XIANG Hongwei1, LI Yongwang1   

  1. 1State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, Shanxi, China 2Graduate University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2009-11-25 Online:2009-11-25 Published:2013-07-17

PDF

847

被引次数

9

摘要： 采用沉淀法和喷雾干燥技术制备了一个典型的费托合成铁基催化剂 (100Fe/3K/6SiO2, 质量比), 所得样品在不同温度下焙烧 5 h. 分别利用 N2 吸附和穆斯堡尔谱表征了催化剂的织构和物相性质, 同时利用热重分析仪记录了催化剂在 H2 气氛中的还原过程, 并利用气固反应模型对还原曲线进行了动力学模拟. 结果表明, 300~600 oC 焙烧后催化剂的还原过程可用相同的模型拟合, 其中由 α-Fe2O3 还原为 Fe3O4 的过程可用一维晶相形成与生长模型或三维相界面反应模型描述, Fe3O4 还原为 α-Fe 的过程受二维晶相形成与生长模型控制. 而对于 700 oC 焙烧后的催化剂,其还原过程可能受晶相形成与生长模型和收缩核模型共同影响. 随着焙烧温度的提高, 催化剂的还原能力减弱, 还原过程活化能升高. 这可能是由于焙烧温度的提高导致晶粒尺寸增大和晶格缺陷减少所致.

关键词: 费托合成, 铁基催化剂, 焙烧温度, 还原动力学, 表观活化能

Abstract: A typical iron-based Fischer-Tropsch catalyst was prepared by the combination of precipitation and spray drying. The catalyst was then calcined at different temperatures. The textural properties and the crystal structure of the calcined catalyst samples were characterized by N2 adsorption and Mössbauer effect spectroscopy, respectively. The thermogravimetric analysis was employed to follow the reduction process of the catalysts. The experimental data were then regressed using gas-solid reaction models. The results indicated that the reduction process of the catalysts calcined at 300–600 oC could be described by the same models. The reduction of α-Fe2O3 to Fe3O4 was regressed by the 1-dimentional formation and growth of nuclei model, and the reduction of Fe3O4 to α-Fe was controlled by the 2-dimentional formation and growth of nuclei model. The reduction of the catalyst calcined at 700 oC was influenced by both the formation and growth of nuclei model and the shrinking core model. With the increase of the calcination temperature, the reduction capability of the catalysts decreased and the apparent activation energy increased, being due to the increase of the crystal size and the decrease of the lattice defects in the catalysts.

Key words: Fischer-Tropsch synthesis, iron-based catalyst, calcination temperature, reduction kinetics, apparent activation energy