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三相间歇流化床中非粘附与粘附体系的沉降-分散模型

张济宇; 林诚; 林春深   

  1. Institute of Chemical Engineering and Technology, Fuzhou University, Fujian 350002, China
  • 收稿日期:1900-01-01 修回日期:1900-01-01 出版日期:2002-04-28 发布日期:2002-04-28
  • 通讯作者: 张济宇

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

ZHANG Jiyu; LIN Cheng; LIN Chunshen   

  1. Institute of Chemical Engineering and Technology, Fuzhou University, Fujian 350002, China
  • Received:1900-01-01 Revised:1900-01-01 Online:2002-04-28 Published:2002-04-28
  • Contact: ZHANG Jiyu

摘要: The axial concentration distribution of both particles with better wetting (forming non-
attached system)and poorer wetting (forming attached system) was investigated in a vertical
gas-liquid-solid fluidized bed of 4.2 cm indiameter and 130 cm in height with the solids
holdup less than 0.05. The one-dimensional sedimentation-dispersionmodel could be used
satisfactorily to describe the axial distribution of solids holdup by modifying only a
modelparameter, i.e. by means of the terminal settling velocity minus a certain value,
which is a function of gas velocityand considers the effect of an additional drag force
resulted from attached rising bubbles. The axial profiles of solidconcentration predicted
are in good agreement with experimental results. This model also explains reasonably
thedifferent axial distributions of solid concentration, i.e. the solids holdup decreases
as the axial height increases innon-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 distributionof solids holdup

Abstract: The axial concentration distribution of both particles with better wetting (forming non-
attached system)and poorer wetting (forming attached system) was investigated in a vertical
gas-liquid-solid fluidized bed of 4.2 cm indiameter and 130 cm in height with the solids
holdup less than 0.05. The one-dimensional sedimentation-dispersionmodel could be used
satisfactorily to describe the axial distribution of solids holdup by modifying only a
modelparameter, i.e. by means of the terminal settling velocity minus a certain value,
which is a function of gas velocityand considers the effect of an additional drag force
resulted from attached rising bubbles. The axial profiles of solidconcentration predicted
are in good agreement with experimental results. This model also explains reasonably
thedifferent axial distributions of solid concentration, i.e. the solids holdup decreases
as the axial height increases innon-attached system, but increases with the axial height in
attached system at a given gas velocity.

Key words: three-phase fluidized bed, terminal settling velocity, sedimentation-dispersion model, axial distributionof solids holdup