费托合成中Co/ZrO2/SiO2催化剂的失活行为

 采用等体积分步浸渍法制备了费托合成用Co/ZrO2/SiO2催化剂,并用XRD,TPR和N2-吸附等手段对催化剂进行了表征. 考察了催化剂在费托反应过程中的结构变化和失活行为. 结果表明,反应过程中硅酸钴物种的生成是催化剂失活的主要原因,且硅酸钴的生成与产物水的分压有关; 晶粒长大也可能是催化剂失活的原因之一.

Deactivation of Co/ZrO2/SiO2 Catalyst for Fischer-Tropsch Synthesis

Cobalt-based catalyst is promising for F-T synthesis, and the study on its deactivation in the reaction is very important. The stability and the structure change of Co/ZrO 2/SiO 2 catalyst in F-T synthesis were investigated. The fresh catalyst sample was black, and the catalyst sample near the bottom of the catalyst bed was pink after reaction for 500 h. The fresh and the used catalyst samples were characterized by XRD, TPR, N 2-adsorption and H 2 pulse adsorption. Cobaltous silicate was the main species in the pink catalyst sample, and it also existed in the used black catalyst sample. The deactivation of Co/ZrO 2/SiO 2 catalyst was caused by the formation of cobaltous silicate. The cobaltous silicate was formed at the bottom of the catalyst bed, which was closely related to the high partial pressure of water by-product. In addition, the N 2-adsorption and pulse H 2-adsorption showed that the accumulation of the active species was one of the probable reasons for the deactivation of the Co/ZrO 2/SiO 2 catalyst.