A study of the release of volatile substances from coals with a dispersed composition reflecting the actual conditions of dust deposition in coal mines

Introduction. It is well known that the particle size distribution of dust significantly influences its explosion hazard. The degree of coal dust’s contribution to an explosion depends on the reduction in the yield of volatile matter, which is dependent on the particle size distribution of the dust. This article examines the validity of an approach to determining the degree of coal dust’s contribution to an explosion based on the reduction in the yield of volatile matter between coal dust samples deposited in mine workings and a control crushed coal bed sample (fraction less than 200 µm).

Research Object and Test Equipment. The article presents a study of coal dust of grade “D”, grade “GZh”, grade “KO” based on technical and chemical analysis for a fraction of less than 20 microns, corresponding to the actual dust deposition in coal mines. A comparison is made with the results of technical and chemical analysis of grade “D”, grade “GZh”, and grade “KO” for fractions smaller than 200 µm.

Experimental results. The obtained results allow us to conclude that the yield of volatile matter from deposited mine dust (fraction less than 20 µm) and crushed formation samples (fraction less than 200 µm) remains constant within the error limits of the GOST 55660–2013 determination method.

Discussion of results. The limited time (7 min) of the volatile matter yield test results in the destruction of outer groups of coal macromolecules with low thermal stability, regardless of the particle size for fractions less than 200 µm.

Conclusions. The results of the study eliminate doubts about the validity of the approach used to determine the degree of coal dust involvement in explosions based on the decrease in the yield of volatile matter in a coal dust sample deposited in mine workings, compared to a control crushed coal bed sample (fraction less than 200 µm).

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