循环流化床内煤粉颗粒团燃烧行为理论分析

循环流化床内的流动属于复杂不均匀的稠密两相流，大部分颗粒在流场内聚集成团，作为一个整体流体团在两相流场中运动与反应。气固之间的反应主要表现为颗粒团与气体之间的反应，因而循环流化床内煤粉的燃烧行为与其他煤粉燃烧形式有很大的区别。该文对不同情况下煤粉的燃烧行为进行了分类，建立了煤粉-物料颗粒团与氧气的异相反应模型，采用上述模型对循环流化床内的煤粉颗粒团的两相流动、反应过程进行详细的分析计算，分析了床内各部分成团效应对煤粉燃烧速率的影响，揭示了煤粉颗粒在床内的燃烧特性，对循环流化床锅炉的优化设计与运行具有重要意义。

Theoretically Studies of the Coal Particle Cluster Combustion Behavior in a Circulating Fluidized Bed

The dense particle-gas two-phase flow in a circulating fluidized bed(CFB)is an essentially non-uniform flow where dozens of particles congregated a cluster and acts as individual and separated objective inside the gas-rich dilute phase.Thus,most particle-gas heterogeneous reaction in a CFB acts as particle-cluster-gas reaction,which is different from that in other reacting technologies.In this paper,the coal particle combustion processes in different reacting cases are detailedly analyzed and classified,and the heterogeneous reacting model between coal particle cluster and oxygen is proposed.Detailed information of the coal-particle-gas two-phase flow and the coal particle cluster combustion behavior in a CFB is obtained.The effects of particle clustering on the coal combustion rate in different zones of a CFD are analyzed.All these results are feasible and provide scientific foundation for optimizing design,operation and control of CFD.