合成氨催化剂颗粒的多组分反应-扩散模型计算  

Multicomponent Reaction-Diffusion Model Calculation of Catalyst Particles for Ammonia Synthesis

作　　者：蒋文超 张海涛[1] 马宏方[1] 李涛[1] JIANG Wenchao;ZHANG Haitao;MA Hongfang;LI Tao(Engineering Research Center of Large Scale Reactor Engineering and Technology of Ministry of Education,East China University of Science and Technology,Shanghai 200237,China)

机构地区：[1]华东理工大学大型工业反应器工程教育部工程研究中心,上海200237

出　　处：《华东理工大学学报（自然科学版）》2022年第6期723-729,共7页Journal of East China University of Science and Technology

摘　　要：基于合成氨反应,利用COMSOL软件建立催化剂颗粒三维多组分反应-扩散模型并进行了验证,模型验证结果与单组分扩散模型结果差距很小;不同形状催化剂的内表面利用率接近,可按照等比外表面积球体进行计算。基于反应器的不同位置对A301催化剂催化过程进行模拟,结果表明:温度、颗粒大小以及反应进程是影响催化剂内扩散效率因子的重要因素。不同反应阶段的扩散效应差异较大,在反应速率较快且内扩散阻滞大的初期,通过减小催化剂粒径提高其内扩散效率因子效果明显,催化剂粒径和内扩散效率因子几乎呈线性负相关关系;反应中后期由于接近化学平衡,催化剂内扩散效率因子可维持在0.95以上的较高水平,且反应对温度和颗粒大小变化不敏感,此时可选取较大粒径催化剂以降低床层压降。Based on the reaction of synthetic ammonia, a three-dimensional multicomponent reaction-diffusion model of catalyst particles was established and verified by COMSOL software. The results of model verification showed that there was little difference between the multicomponent diffusion model and the one-component diffusion model. The inner surface utilization of ammonia catalysts with different shapes was close to each other. In industrial reactors, the calculation of internal diffusion efficiency factor of ammonia synthesis catalyst could be carried out according to the uniform surface area of spheres. Based on the different positions of the reactor, the simulation results of the synthesis ammonia A301 catalyst show that temperature, particle size and reaction process are important factors affecting the diffusion efficiency of catalyst. The diffusion effects of different reaction stages are quite different. At the initial stage of reaction, when the reacting rate and the internal diffusion retardation is large, the internal diffusion efficiency factor can be improved obviously by reducing the particle size of catalyst. The results show that the efficiency factor is almost linearly negatively correlated to the particle size of catalyst. In the middle and late stages,when the reaction is close to equilibrium, the utilization rate of the inner surface of the catalyst can remain above 0.95,and the internal diffusion is not sensitive to the changes of temperature and particle size. In this case, the catalyst with an appropriate large particle size can be selected in the reactor in order to reduce the pressure drop of the catalyst bed.

关 键 词：合成氨催化剂 反应-扩散 内扩散效率因子 反应器 模型优化 

分 类 号：TQ013.2[化学工程]