Multi-scale aggregation of particles in gas-solids fluidized beds--颗粒学报PARTICUOLOGY

Li, H. (2004). Multi-scale aggregation of particles in gas-solids fluidized beds. China Particuology, 2(3), 101-106. https://doi.org/10.1016/S1672-2515(07)60033-5

Multi-scale aggregation of particles in gas-solids fluidized beds

Hongzhong Li ^*

Multi-Phase Reaction laboratory, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100080, P. R. China

10.1016/S1672-2515(07)60033-5

Volume 2, Issue 3, June 2004, Pages 101-106

Received 16 March 2004, Accepted 30 April 2004, Available online 27 November 2007.

E-mail: hzli@home.ipe.ac.cn

Highlights

Abstract

The multi-scale characteristics of clusters in a fast fluidized bed and of agglomerates in a fluidized bed of cohesive particles are discussed on the basis of large amounts of experiments. The cluster size and concentration are dominated by the local voidage of the bed. A cluster consists of many sub-clusters with different sizes and discrete particles, and the sub-cluster size probability density distribution appears as a negative exponential function. The agglomerates in a fluidized bed of cohesive particles also possess the multi-scale nature. The large agglomerates form a fixed bed at the bottom, the medium agglomerates are fluidized in the middle, and the small agglomerates and discrete particles become the dilute-phase region in the upper part of the bed. The agglomerate size is mainly affected by cohesive forces and gas velocity. The present models for predicting the size of clusters and agglomerates can not tackle the intrinsic mechanism of the multi-scale aggregation, and a challenging problem for establishing mechanistic model is put forward.

Graphical abstract

Keywords

fluidization; cohesive particles; cluster; agglomerate; multi-scale structure; powder technology

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