Effect of the secondary air distribution layer on separation density in a dense-phase gas–solid fluidized bed  

作　　者：Lv Bo Luo Zhenfu Zhang Bo Zhao Yuemin Zhou Chenyang Yuan Wenchao 

机构地区：[1]School of Chemical Engineering and Technology, China University of Mining and Technology

出　　处：《International Journal of Mining Science and Technology》2015年第6期969-973,共5页矿业科学技术学报（英文版）

基　　金：the Key Project of National Fundamental Research and Development of China (No. 2012CB214904);the National Natural Science Foundation of China for Innovative Research Group (No. 51221462);the National Natural Science Foundation of China (Nos. 51134022 and 51174203);Specialized Research Fund for the Doctoral Program of Higher Education (No. 20120095130001)

摘　　要：Dry coal separation has been the most significant process in the field of coal beneficiation to date, because of its special advantage of operation with no water consumption. Mineral dry separation research has received wide attention, particularly in countries and regions experiencing drought and water shortages. During the process of dense coal gas-solid fluidized bed beneficiation, the material is stratified according to its density; the high density material layer remains at the bed bottom, and thus the high density coarse particle bed becomes an important infuencing factor in fluidized bed stability. In the steady fluidization stage, a small number of large radius bubbles are the direct cause of unsteady fluidization in the tradi- tional fluidized bed. The dispersion effect of the secondary air distribution bed for air flow is mainly apparent in the gas region; when the particle size exceeds 13 mm, the secondary air distribution bed has a synergistic effect on the density stability of the upper fluidized layer. When the particle size is small, especially when less than 6 ram, particles will constantly move, accounting for instability of the secondary air distribution bed and distorting the stability of the upper fluidized bed. Under optimum operation conditions, the probable deviation E of gas-solid separation fluidized with a high density coarse particle layer can be as low as 0.085 g/cm3.Dry coal separation has been the most significant process in the field of coal beneficiation to date, because of its special advantage of operation with no water consumption. Mineral dry separation research has received wide attention, particularly in countries and regions experiencing drought and water shortages.During the process of dense coal gas–solid fluidized bed beneficiation, the material is stratified according to its density; the high density material layer remains at the bed bottom, and thus the high density coarse particle bed becomes an important influencing factor in fluidized bed stability. In the steady fluidization stage, a small number of large radius bubbles are the direct cause of unsteady fluidization in the traditional fluidized bed. The dispersion effect of the secondary air distribution bed for air flow is mainly apparent in the gas region; when the particle size exceeds 13 mm, the secondary air distribution bed has a synergistic effect on the density stability of the upper fluidized layer. When the particle size is small, especially when less than 6 mm, particles will constantly move, accounting for instability of the secondary air distribution bed and distorting the stability of the upper fluidized bed. Under optimum operation conditions, the probable deviation E of gas–solid separation fluidized with a high density coarse particle layer can be as low as 0.085 g/cm3.

关 键 词：Secondary air distribution layerDry coal separationGas-solid fluidized bedParticle size 

分 类 号：TD94[矿业工程—选矿]