The CFD simulation of the egg-shell Co-based catalyst Fischer-Tropsch synthesis reaction system was carried out by Comsol-Multiphysics software. The effects of catalyst active component thickness on product and temperature distribution

conversion of F-T synthesis were studied by establishing a reasonable three-dimensional model of catalyst. The results show that the CO concentration has obvious difference between the outside and inside of catalyst due to strong diffusion limitation. And because the diffusion rate of H2 is much larger than the diffusion rate of CO

the internal hydrogen-carbon ratio of the catalyst particles is very high

which is not conducive to the formation of oils and waxes. As the thickness of catalyst active components increases

the conversion of CO and the selectivity of methane and low hydrocarbons increases

while the selectivity of C10H22 and C22H46 decreases. The peak temperature inside the catalyst moves towards the inside of the catalyst

which isn’t conducive to the transfer of reaction heat. For the shell-type spherical catalyst with the size of 2.5mm

the optimum catalyst thickness of the active component is 0.125 mm.