A method to improve fluidization quality in gas-solid fluidized bed for fine coal beneficiation

Dry coal separation has become essential in China because it does not consume water and it reduces environmental pollution. In this study, a method for improving fluidization quality in a fluidized bed separator using a micropore sponge is proposed. The separator is used for fine coal beneficiation. The pressure drop across the distributor and bed fluidization characteristics were analyzed to evaluate fluidization quality. The beneficiation efficiency for fine coal was further investigated by using a laboratory-scale fluidized bed with and without a micropore sponge. With the sponge, the highest pressure drop fluctuation factor decreased from 0.23 to 0.16, indicating an improvement in density stability. The modified separation method reduced the ash content of a sample of fine coal from 23.83% to 10.70%. The probable error efficiency value E for -6+3 mm coal was 0.12 g/cm(3), close to the efficiency error values reported for other dry-beneficiation techniques. The separation results show that using a sponge in the fluidized bed can readily improve the efficiency of fine coal beneficiation. (C) 2018 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.