In this study we investigate performance characteristics (catalyst effectiveness, CH₄ selectivity, and hydrocarbon product distribution) of with a highly active Co/Re/Al₂O₃ catalyst particle for Fischer-Tropsch synthesis. In numerical simulations we utilize kinetic parameters for CO consumption rate, CH₄ formation rate and hydrocarbon formation rates (C₂+ hydrocarbons) determined from experiments with this catalyst to study effects of catalyst activity, catalyst particle shape (sphere, slab, solid and hollow cylinder), size (i.e. diffusion length), catalyst distribution (uniform vs. eggshell type distribution for a spherical particle) and process conditions (temperature, pressure, syngas composition and conversion level) on the catalyst performance. With increase in Thiele modulus (i.e. particle size at a fixed set of process conditions) we observe increasing H₂/CO ratio profile towards the center of the particle resulting in increase of local and average CH₄ selectivity. The goal is to find conditions which allow one to use sufficiently large particles to reduce pressure drop, while avoiding negative influence of diffusional limitations on selectivity and activity. For each catalyst particle shape we determined values of Thiele modulus, i.e. characteristic length of diffusion, corresponding to the upper limit of the kinetic region, and investigated how it changes with operating conditions. We found that simultaneous increase of pressure and the use of syngas with H₂/CO feed ratio of 1.4–1.7 is the best strategy for mitigating the negative impact of intraparticle diffusional limitations on CH₄ selectivity. For a spherical particle of 1 mm in diameter, one can achieve CH₄ selectivity of 5.6% with catalyst effectiveness factor of 1.07 at the reactor inlet by operating at 50 bar, 473 K and H₂/CO = 1.4.

在这项研究中，我们研究了费-托合成用高活性Co / Re / Al ₂ O ₃催化剂颗粒的性能特征（催化剂效力，CH ₄选择性和烃产物分布）。在数值模拟中，我们将动力学参数用于CO消耗速率，CH ₄形成速率和烃形成速率（C ₂由使用该催化剂的实验确定的+碳氢化合物），以研究催化剂活性，催化剂颗粒形状（球形，平板，实心和空心圆柱），尺寸（即扩散长度），催化剂分布（球形颗粒的均匀与蛋壳型分布）的影响）和工艺条件（温度，压力，合成气组成和转化率）对催化剂性能的影响。随着Thiele模量的增加（即在一组固定的工艺条件下的粒径），我们观察到朝向颗粒中心的H ₂ / CO比分布增加，导致局部和平均CH _4的增加选择性。目的是找到允许人们使用足够大的颗粒来减少压降的条件，同时避免扩散限制对选择性和活性的负面影响。对于每种催化剂颗粒形状，我们确定了Thiele模量的值，即扩散的特征长度，对应于动力学区域的上限，并研究了其如何随操作条件而变化。我们发现，同时增加压力和使用H ₂ / CO进料比为1.4–1.7的合成气是减轻颗粒内扩散限制对CH ₄选择性的负面影响的最佳策略。对于直径为1 mm的球形颗粒，可以达到CH ₄通过在50巴，473K和H ₂ /CO＝1.4下操作，在反应器入口处的选择性为5.6％，催化剂效率因子为1.07 。