关键词: 微通道, 费托合成, 反应动力学, 催化剂层厚度, 数值分析

Abstract: According to Fischer-Tropsch synthesis(F-T) reaction kinetics of Fe-based catalysts, a two-dimension model has been developed with COMSOL-Multiphysics by coupling flow, mass transfer, chemical reactions and heat transfer fields. The characteristics of Fischer-Tropsch synthesis in micro-channel has been studied with this model. Detailed research has been taken on the effect of the thickness of catalytic layers and cooling velocity to F-T reactions, heat and mass transfer performance. The numerical results show that, along the axial direction, temperature increased slowly and then declined quickly. By increasing the thickness of catalytic layers, the temperature peak moved away from outlet, CO conversion was improved, methane selectivity increased while C₅₊ selectivity decreased slightly. It's possible to have better temperature control, improve C₅₊ selectivity, and significantly reduce the selectivity of CH₄ by increasing cooling velocity. Under the set researching conditions (the cross-sectional dimension of the micro-channel is 0.6×0.6mm² with a length of 200mm), the preferred catalyst thickness is 0.10mm, also, with the enhancement of the cooling capacity on cooling side, the preferred thickness increases.

Key words: micro-channel, Fischer-Tropsch synthesis, reaction kinetics, thickness of catalytic layers, numerical analysis