Abstract: Through model establishment, grid partitioning, and solution settings (including boundary conditions, chemical reaction mechanisms, porous media and their heat transfer models, turbulence models, solution methods, etc.), numerical simulations were conducted on the thermal catalytic degradation of SF6 in a thermal catalytic reactor. The pressure distribution, velocity distribution, temperature distribution, and concentration distribution of various substances in the reactor were obtained. Pressure, temperature, gas flow rate, and substance concentration all exhibited inconsistency between the central axis and the wall surface. It was found that temperature had the most impact on degradation efficiency of SF6, uneven radial temperature distribution within the reactor lead to a decrease in SF6 degradation efficiency. Based on the analysis results, the optimization design of the reactor was carried out to solve the uneven distribution of the various parameters. The influence of gas flow rate and reaction tube inner diameter size on heat and mass transfer in the reactor was studied. Measures such as reducing reactor diameter and filling inert porous media components with high thermal conductivity were proposed to enhance heat transfer and optimize temperature field distribution to improve SF6 degradation efficiency. After adding porous media at both ends of the catalytic section, the temperature field, reaction rate and substance concentration distribution became more uniform compared to that before optimization. By studying the effect of inlet gas flow rate on reactor performance, it was found that too low or too high inlet gas flow rate can deteriorate effective utilization or heat transfer efficiency in the catalytic zone, resulting in uneven radial distribution of temperature field and reduced degradation efficiency of SF6. The optimal gas flow rate should be controlled between 0.4~0.8 m/s, which can balance the utilization, energy consumption and degradation efficiency of the catalyst. This study provides data support and theoretical guidance for the design, optimization, and practical application of SF6 catalytic degradation reactors.

Key words: sulfur hexafluoride, thermal catalytic degradation, CFD simulation, reactor optimization

摘要： 通过模型建立、网格划分和求解设置（包括边界条件、化学反应机理、多孔介质及其传热模型、湍流模型、求解方法等）对热催化反应器内SF6热催化降解进行数值模拟，得到反应器内的压力分布、速度分布、温度分布和各物质的浓度分布情况，并以此为基础进行反应器的优化设计，研究了流速和反应管内径大小对反应器内传热和传质的影响。研究发现，反应器内的温度场径向分布不均导致SF6降解效率降低。基于模拟结果，提出减小反应器管径、装填导热性良好的惰性多孔介质组分等措施，可以强化传热，优化温度场分布以提高SF6降解效率。通过研究入口速度对反应器性能的影响，得出最佳流速控制在0.4~0.8 m/s，可以平衡催化剂的利用、能耗及降解效率。本研究为SF6催化降解反应器的设计、优化及实际应用提供了数据支持和理论指导。

关键词: 六氟化硫, 热催化降解, CFD模拟, 反应器优化