内扩散行为对F-T合成反应过程影响的研究

Effect of intraparticle diffusion on F-T synthesis

摘要: 选用Co/ZrO₂催化剂，通过改变催化剂颗粒径，在积分固定床反应器上研究了内扩散行为对F-T合成反应过程的影响。以表观活化能、烯/烷比的变化等为依据，考察了内扩散行为对F-T合成反应历程、催化剂活性及产物选择性的影响。催化剂颗粒径不同，内扩散限制程度会发生相应变化。实验结果表明，不同程度的内扩散限制条件下，F-T合成反应历程会有较大差异。当反应开始后，颗粒内孔从“干”到“湿”，不同粒径的催化剂颗粒上气态烯/烷比变化均呈“U”型趋势。在固定床反应器上，增加空速通常会有CH₄选择性升高、气态烯/烷比略有增加的现象，这是由于内扩散限制未完全消除的缘故。

Abstract: The effect of intraparticle diffusion on the performance of Co/ZrO₂ F-T catalyst was investigated. According to the change of apparent activation energy, the reaction pathway might vary while changing the extent of diffusion limitation. After catalysts were activated, the inner pores would be filled with F-T product gradually. The ratio of gaseous olefin to paraffin followed the “U” type trend. The selectivity to CH₄ increased with the increase of GHSV. And the ratio of gaseous olefin to paraffin also increased slightly with the increase of GHSV due to the intraparticle diffusion limitation.