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 (Pmax), 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 Pmax-G, that of a gas–dust mixture Pmax-GD was elevated when a 7.0 vol% methane–air mixture coexisted with 500.0 g m−3 of coal dust in the explosion. Pmax-GD decreased as CG increased and increased as Vad increased for a methane–air–coal dust mixture. Both Pmax-GD and (dP/dt)max-GD increased first, but were diminished with an increase in CD. The Copt 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 Kg was consistently lower than the explosion index of a gas–dust mixture Km; that is, Kg < Km.