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

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.