大颗粒煤反应过程中灰层有效扩散系数的研究

OVERVIEW OF STUDY ON EFFECTIVE DIFFUSIVITY OF COAL CHAR PARTICLE REACTION

在大颗粒煤燃烧或者气化过程中,气体穿过灰层的有效扩散系数是非常重要的参数.对有效扩散系数的研究主要有两种思路:一方面,灰层本质上是多孔介质,因此在研究有效扩散系数时,沿用气体在多孔介质中扩散的研究思路;另一方面,焦炭的燃烧或者气化本质上是气固反应,气体在灰层也即产物层中的扩散是气固反应的重要影响因素,因此应用气固反应的理论对有效扩散系数进行研究.根据以上两种思路综述了有效扩散系数的实验和模型的研究现状,并对今后的研究重点进行了展望.

An overview is presented on the experiment and modeling study of effective diffusivity through the ash layer, which is a key parameter when describing coal char particle combustion or gasification. There are two theories studying the effective diffusivity. Ash layer is a porous media, so the theory of diffusion through porous media can be adopted. On the other hand, coal char combustion or gasification is gas-solid reaction, so the gas-solid reaction theory can be used. Some suggestions on studying the effective diffusivity in the future are also given.