A Sedimentation-Dispersion Model for both Non-attached and Attached Particles in Three-Phase Batchwise Fluidized Beds  

作　　者：张济宇 林诚 林春深 

出　　处：《Chinese Journal of Chemical Engineering》2002年第2期170-176,共7页中国化学工程学报（英文版）

基　　金：Supported by the Fujian Provincial Education Council (No. JB9940).

摘　　要：The axial concentration distribution of both particles with betterwetting (forming non-attached system) and poorer wetting (formingattached system) was investigated in a vertical gas-liquid-solidfluidized bed of 4.2 cm in diameters and 130 cm in height with thesolids holdup less than 0.05. The one-dimensionalsedimentation-dispersion model could be used satisfactorily todescribe the axial distribution of solids holdup by modifying only amodel parameter, i.e. by means of the terminal settling velocityminus a certain value, which is a functions of gas velocity andconsiders the effect of an additional drag force resulted fromattached rising bubbles.The axial concentration distribution of both particles with better wetting (forming non-attached systems) and poorer wetting (forming attached system) was investigated in a vertical gas-liquid-solid fluidized bed of 4.2cm in diameter and 130cm in height with the solids holdup less than 0.05. The one-dimensional sedimentation-dispersion model could be used satisfactorily to describe the axial distribution of solids holdup by modifying only a model parameter,i.e.by means of the terminal settling velocity minus a certain value,which is a function of gas velocity and considers the effect of an additional drag force resulted from attached rising bubbles.The axial profiles of solid concentration predicted are in good agreement with experimental results.This model also explains reasonably the different axial distribution of solid concentration,i.e.the solids holdup decreases as the axial height increases in non-attached system,but increases with the axial height in attached system at a given gas velocity.

关 键 词：three-phase fluidized bed terminal settling velocity sedimentation-dispersion model axial distribution of solids holdup 

分 类 号：TQ021[化学工程]