Experimental data revealing explosion characteristics of methane, air, and coal mixtures

Abstract

Whenever air and gases mix with pulverised coal, explosions are possible. Such explosions constitute a primary category of safety concerns during coal bed methane mining. This study investigated the explosion parameters and characteristics of methane–air–coal dust mixtures by using an XKWB-1 sealed explosion system. Maximum explosion pressure (P_max), maximum explosion pressure rise rate (dP/dt)_max, and explosion index (K) were recorded and calculated. Findings showed that relative to the maximum explosion pressure of an air–methane gas mix P_max-G, that of a gas–dust mixture P_max-GD was elevated when a 7.0 vol% methane–air mixture coexisted with 500.0 g m⁻³ of coal dust in the explosion. P_max-GD decreased as C_G increased and increased as V_ad increased for a methane–air–coal dust mixture. Both P_max-GD and (dP/dt)_max-GD increased first, but were diminished with an increase in C_D. The C_opt values of five coal samples of HC, KZD, DFS, TC, and YMZ were 400.0, 500.0, 500.0, 500.0, and 600.0 g m⁻³, respectively. Based on the coal dust explosion pathways, the effects of coal dust volatility on the explosion characteristics were analysed. Finally, with respect to 7.0 vol% methane, the data showed that the explosion index of a gas K_g was consistently lower than the explosion index of a gas–dust mixture K_m; that is, K_g < K_m.