( 1. 东北大学 资源与土木工程学院， 沈阳 110004；
2. 东北大学 材料与冶金工程学院，沈阳 110004)
摘 要: 考虑到冶金固定床是颗粒堆积的松散多孔介质， 首先将单一颗粒的动力学方程推广到多颗粒的微元体上， 导出了化学反应项的具体形式， 建立了冶金固定床一维对流、 反应、 扩散方程， 然后求出其解析解； 通过实例计算分析主气流中反应气体的浓度分布。 结果表明： 颗粒大小和孔隙率对反应进程有很大的影响， 其影响可以用Thiele数和Peclet数定量衡量； 微元体的反应类型不等于反应器的反应类型； 化学反应速率对反应气体浓度的影响超过对流速度， 而扩散的影响最小； 微元体的综合反应速率、 对流速度以及反应器的长度本身是影响反应器反应类型的重要因素。
关键字: 颗粒动力学； 微元体动力学； 化学反应； 对流； 扩散； 解析解
（ 1. School of Resource and Civil Engineering,
Northeastern University, Shenyang 110004, China;
2. School of Material and Metallurgy,
Northeastern University, Shenyang 110004, China）
Abstract: In view of the fact that fixed bed is porous media of granule aggregation, the dynamics of a single particle is extended to the dynamics of representative-element volume including multiple particles, so that the more exact chemical reaction term can be deduced. Then one-dimensional model for instable convection, chemical reaction and diffusion in fixed bed is proposed and solved analytically. Computation cases show that the scale of pellet and the porosity of bed have great impact on the reaction process taking place in reactor, which can be measured by Thiele module and Peclet module, the reaction behavior of REV is not the same as that of reactor. For the gas concentration, chemical reaction has greater impact than convection has, because Thiele module is proportional positively to L2/D and Peclet module is to L/D, and diffusion has the least impact. The overall rate of REV, length of reactor itself and convection all contribute remarkably to the performance of reactor.
Key words: dynamics of single particle; dynamics of representative-element volume; chemical reaction; convection and diffusion; analytical solution
