Micromixing characteristics in a gas-liquid-solid stirred tank with settling particles  

下沉颗粒气-液-固搅拌槽内微观混合特性研究（英文）

作　　者：栗万博 耿兴业 包雨云 高正明 

机构地区：[1]State Key Laboratory of Chemical Resource Engineering,School of Chemical Engineering,Beijing University of Chemical Technology

出　　处：《Chinese Journal of Chemical Engineering》2015年第3期461-470,共10页中国化学工程学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(20990224,21121064,21206002)

摘　　要：The parallel-competing iodide-iodate reaction scheme was used to study the micromixing performance in a multi-phase stirred tank of 0.3 m diameter.The impeller combination consisted of a half elliptical blade disk turbine below two down-pimping wide-blade hydrofoils,identified as HEDT + 2WH_D.Nitrogen and glass beads of100 μm diameter and density 2500 kg-m^(-3) were used as the dispersed phases.The micromixing could be improved by sparging gas because of its additional potential energy.Also,micromixing could be improved by the solid particles with high kinetic energy near the impeller tip.In a gas-solid-liquid system,the gas-liquid film vibration with damping,due to the frequent collisions between the bubbles and particles,led to the decrease of the turbulence level in the liquid and caused eventually the deterioration of the micromixing.A Damping Film Dissipation model is formulated to shed light on the above micromixing performances.At last,the micromixing time t_m according to the incorporation model varied from 1.9 ms to 6.7 ms in our experiments.The parallel-competing iodide-iodate reaction scheme was used to study the micromixing performance in a multi-phase stirred tank of 0.3 m diameter.The impeller combination consisted of a half elliptical blade disk turbine below two down-pimping wide-blade hydrofoils,identified as HEDT ＋ 2WHD.Nitrogen and glass beads of100 μm diameter and density 2500 kg-m（-3） were used as the dispersed phases.The micromixing could be improved by sparging gas because of its additional potential energy.Also,micromixing could be improved by the solid particles with high kinetic energy near the impeller tip.In a gas-solid-liquid system,the gas-liquid film vibration with damping,due to the frequent collisions between the bubbles and particles,led to the decrease of the turbulence level in the liquid and caused eventually the deterioration of the micromixing.A Damping Film Dissipation model is formulated to shed light on the above micromixing performances.At last,the micromixing time tm according to the incorporation model varied from 1.9 ms to 6.7 ms in our experiments.

关 键 词：Stirred tank Gas-liquid-solid Micromixing performance Incorporation model 

分 类 号：TQ027.1[化学工程]