【摘要】 等离子体裂解煤的反应器结构影响气固混合效果。运用计算流体力学(CFD)的FLUENT软件对喉管式反应器内等离子体射流和煤粉的气固流动和混合行为进行了初步的数值模拟,对颗粒在反应器内的加速历程进行了描述,并与传统的直管式反应器进行了比较。结果发现喉管式反应器可以分为混合段和反应段两部分,它特殊的结构设计能够增加煤粉颗粒的入射深度,延长颗粒与气流的作用时间,增大气固两相的接触面积。结合小试结果证明了模拟结果的可靠性。最后讨论了反应段尺寸对流场的影响,表明较小的渐扩比可以减小回流区的范围,选择合适的管径与管长可以获得煤粉与射流的最佳接触时间。更多还原

【Abstract】 The structure of thermal plasma reactor for coal pyrolysis has a significant effect on the gas-solid mixing effect. A preliminary numerical simulation of the gas-solid flow and mixing behavior of plasma jet and pulverized coal in a venturi reactor was carried out. The simulation result was compared with that of the tubular reactor. The results showed that the venturi reactor could be divided into two parts: one for mixing and the other for reacting. Its special structure could increase the incident depth of the pulverized coal particles, prolong residence time and increase the contact area for the two phases. The result of 50 kW experiment confirmed our simulation. Finally, the influence of the reaction section size on the flow field was discussed. It showed that the range of the recirculation zone was reduced in the smaller divergence ratio. The optimal contacting time between pulverized coal and jet could be obtained by selecting appropriate pipe diameter and length.更多还原