Experimental study on sieving phenomenon and particle size distribution characteristics of coal particles

doi:10.16265/j.cnki.issn1003-3033.2022.02.018

Abstract

Abstract:

In order to investigate influence of mean particle sizes on the calculation of coal's physical property parameters, screening phenomenon and particle size distribution of coal particles at five fractions were studied. Then, with solution of coal gas diffusion coefficient as an example, effects of arithmetic mean and volume-weighted mean volume particle size on calculation results were analyzed. The results show that special separation phenomenon occurs during screening process of coal particles, and distribution of target fractions only accounts for 33.37%—49.32% of real size distribution. And arithmetic mean makes all sieved particle sizes within the target fraction, which causes a large error in calculating the diffusion coefficient. Compared it with the volume-weighted average volume size which considers characteristics of particle size distribution, the difference of diffusion coefficient between the two solutions is up to 43.42%.

Key words: coal particle sieving, particle size distribution, mean particle size, diffusion coefficient, desorption

LIU Qingquan, LIU Yuanyuan, DU Kai, ZHENG Siwen, ZHU Zibin. Experimental study on sieving phenomenon and particle size distribution characteristics of coal particles[J]. China Safety Science Journal, 2022, 32(2): 130-138.

Figures/Tables 11

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粒级/ mm	筛分时间/min	筛分现象	粒度测定	粒径简化
[1, +∞)	5/10/ 15/20/25	√	—	—
[0.3,1)		√	—	—
[0.18,0.3)		√	√	√
[0.1,0.18)		√	√	—
[0.075,0.1)		√	—	—

样品名称	算术平均值		体积加权平均体积粒径		差异量/%
样品名称	粒径/mm	扩散系数D/ (10^-11×m²·s^-1)	粒径/mm	扩散系数D/ (10^-11×m²·s^-1)	差异量/%
5号	0.214	2.227	0.208	2.103	5.57
10号			0.161	1.260	43.42
15号			0.227	2.506	12.53
20号			0.203	2.004	10.01
25号			0.225	2.462	10.55