气固并流下行床气体扩散行为的研究  

GAS MIXING IN A COCURRENT DOWNFLOW CIRCULATING FLUIDIZED BED

作　　者：魏飞[1] 刘金忠[1] 金涌[1] 俞芷青[1] 

机构地区：[1]清华大学化工系,北京100084

出　　处：《化工学报》1994年第4期429-434,共6页CIESC Journal

基　　金：国家自然科学基金资助项目

摘　　要：采用氢气稳态示踪方法在内径140mm的气固并流下行循环流化床中对气体扩散行为进行了实验研究.实验结果表明:下行床中气体扩散行为可用二维拟均相模型进行描述,其气体的径向扩散系数与气速、固体循环量及颗粒密度的关系可用下列准数关联式表示Pe_r=4.35×10_(-3)Re^(0.95)ε^(-73.4) 1>ε>0.99而下行床中气体轴向扩散系数要比提升管中小1个数量级以上.An experimental study on the gas dispersion behavior of cocurrent downflow gas-solid suspension in a 140 mm i. d. circulating fluidized beds (CDCFB) using the steady-state tracer method is presented. The influence of gas velocity, solids circulating rate and particle density on radial gas dispersion has been examined. Gas dispersion can well be described by eddy diffusion mechanics and a proposed two dimensional dispersed plug- flow model fits the experimental data very well. The correlation Per = 4. 35× 10-3Re0.95ε-73.4(while 1>ε>0. 99) for radial diffusion coefficient is obtained. It is found that the obtained axial diffusion coefficient in the CDCFB is much lower than that in a circulating fluidized bed.

关 键 词：并流下行 气体扩散 流化床反应器 

分 类 号：TQ051.13[化学工程]