单颗粒催化剂上非理想体系的反应-扩散模型(Ⅱ)实例分析

A MODEL OF DIFFUSION - REACTION PROCESSES OVER A CATALYST PELLET FOR NON - IDEAL REACTION SYSTEM (Ⅱ) NUMERICAL SIMULATION EXAMPLES

在本文(I)报建立的非理想尘气模型和非理想广义Stefan-Maxwell模型的基础上,结合常规反应-扩散模型,以氨和甲醇合成为例,研究了反应物系的非理想性对单颗粒催化剂效率因子模拟结果的影响.这些模拟结果之间以及甲醇合成模拟值与实验值之间的对比分析表明:描述这两个反应体系催化剂颗粒上的反应-扩散问题,必须考虑反应物系的非理想性.对于氨的合成,非理想费克模型已足以近似描述颗粒内的反应-扩散过程;但对于以CO/CO_2/H_2为原料的甲醇合成,采用非理想广义Stefa-Maxwell模型或非理想尘气模型比较适宜.

Based on the non - ideal Dusty - Gas Model (NDGM) and non - ideal Extended Stefan -Maxwell Model developed in the first part of this paper, and other models used widely for modeling the diffusion - reaction processes over a catalyst pellet, the effect of non - ideal characteristics of the reaction mixture on the predicted effectiveness factors of the catalyst is numerically studied for ammonia and methanol synthesis reactions. Parameter analysis of this effect has also been completed. The computation results and the comparison between the model prediction results and those observed show that non - ideal characteristics should be taken into account for those two reaction systems. NFICK is acceptable for ammonia synthesis reaction, but NESM or NDGM should be adopted for methanol synthesis from CO/CO2/ H2 gas mixture.