鼓泡床高度对多段气化炉内颗粒分布的影响

Effect of Different Bubbling Bed Height on Particle Distribution in Multi-stage Gasifier

多段气化炉反应器主体由下部鼓泡床和上部快速床组成,是一种新型的煤分级转化集成技术。针对三维全循环多段气化炉,采用MP-PIC(mult-phase particle in cell,Barracuda)方法模拟了多粒径煤粉颗粒的循环流化过程,研究了鼓泡床高度对气化炉内流动特性的影响。研究发现:①在适当范围内,降低鼓泡床高度,床体更快达到稳定操作状态;②快速床上部颗粒浓度随鼓泡床构体高度增加而降低;③鼓泡床高度的增加使得过渡段上部和快速床下部的细颗粒(<1 000μm)含量增加;④靠近快速床出口截面处最小颗粒的含量随鼓泡床高度增大而单调增加。这些规律对多段气化炉的设计和优化具有参考意义。

The multi-stage gasifier,which is mainly composed of a lower bubbling fluidized bed and an upper fast fluidized bed,is a novel integration technology of coal grading conversion.The 3D full-loop multi-stage gasifier was simulated with MP-PIC(Multi-Phase Particle In Cell)method successfully.The effect of different bubbling bed height on the flow characteristics of gasifier was systematically studied.The results show that:①The system approaches steady state faster when decreasing the bubbling bed height.②The particle concentration in the fast bed decreases as the height of the bubbling bed increases.③The content of fine particles(<1 000μm)in the upper part of the transition section and the lower part of the fast bed increases with increasing of the height of the bubbling bed.④The content of the fine particles near the exit section of the fast bed is increasing monotonously with the height of the bubbling bed increasing.These rules can be significant and helpful to the design and optimization of multi-stage gasifiers.