The low effectiveness factor of catalyst pellet caused by high internal diffusion limitation is a common issue in fixed-bed reactor. Nevertheless, hierarchical structured catalyst provides a promising solution for the contradiction between reaction activity and diffusion efficiency in large catalyst pellets. Herein, we studied the effect of pore structure parameters of the meso-macroporous catalyst on Fischer–Tropsch synthesis performances through experiment and pellet scale reaction–diffusion simulation. The pellet simulation firstly elucidated the reason for the significant improvement on activity and product selectivity for the meso-macroporous catalyst observed in our experiment. Further optimization via pellet simulation indicated the critical influences of wax filling degree and that the perfect matching between reaction and mass transfer rates by increasing macropore size and adjusting porosity within pellet enables the C₅₊ space–time yield to the maximum. This work could provide a theoretical guideline for the engineering design of the hierarchical structured catalyst pellet.

中文翻译：

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费托合成中分层结构钴基催化剂颗粒的传质优势

由高内部扩散限制引起的催化剂颗粒的低效率因子是固定床反应器中的普遍问题。然而，分级结构催化剂为大催化剂颗粒中反应活性和扩散效率之间的矛盾提供了有希望的解决方案。在本文中，我们通过实验和颗粒级反应扩散研究了介孔催化剂的孔结构参数对费-托合成性能的影响。颗粒模拟首先阐明了在我们的实验中观察到的介孔催化剂的活性和产物选择性显着提高的原因。通过进一步优化颗粒模拟显示了蜡填充度的关键影响，并且通过增加颗粒的大孔尺寸和调节孔隙率，反应与传质速率之间的完美匹配使C ₅₊时空产率达到最大。这项工作可以为分层结构化催化剂颗粒的工程设计提供理论指导。