Influence of electrostatic field on coal gas diffusion characteristics in coal

doi:10.16265/j.cnki.issn1003-3033.2020.07.010

Abstract

Abstract: In order to explore influence of electrostatic field on gas diffusion characteristics in coal, a gas desorption and diffusion test system was independently designed, and desorption and diffusion volume of coals were measured under electric field intensity of 0, 40, 120 and 240 kV/m respectively with samples of different metamorphism selected from Guhanshan Mine, Hebi No. 6 Mine, Pingdingshan No. 8 Mine and Yimagengcun Mine. Then, their diffusion coefficient was calculated by using classical single hole diffusion model. The results show that diffusion coefficient of coal samples increases first and then decreases in a parabolic form along with increase of applied electric field strength. It reaches the maximum when characteristic dominant electric field strength is 40 kV/m, but will decrease while under other electric field intensities. Based on comparison of diffusion characteristics of these samples under electric field strength, it is found that coefficient of fat coal in Pingdingshan Mine is the largest while lignite in Yima Mine is the smallest. Reasons for diffusion characteristics variance under electrostatic field are that induced polarization of coal and gas molecules changes adsorption potential well depth on coal surface, and also electric field can cause volume percentage and specific surface area of micro pores in coal to increase (decrease).

Key words: coal gas, electrostatic field, diffusion coefficient, electric field intensity, desorption and diffusion volume

CLC Number:

X936

LEI Dongji, MA Tao, MENG Hui, XUE Qunshan. Influence of electrostatic field on coal gas diffusion characteristics in coal[J]. China Safety Science Journal, 2020, 30(7): 62-68.

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