Experimental Study on Explosion Characteristics of Ultra-Low Concentration Methane Mixed with Dimethyl Ether

Abstract

Low-concentration methane accounts for the most massive percent of coal mine methane (CMM). Reasonable utilization of low-concentration methane, especially the ultra-low concentration methane (less than 5%), is of great significance for resource conservation and environmental protection. Therefore, a reasonable utilization method of ultra-low concentration methane (ULCM) was proposed. The main idea is to add combustible substances, such as dimethyl ether (DME), into ULCM to promote its combustion and explosion. The experimental investigations on the explosion parameters of ULCM mixed with DME were conducted in a horizontal explosion pipeline. The results suggested that the addition of DME can promote the combustion and explosion of ULCM. The maximum values of v and Pmax appear in the equivalence ratio of 1.1–1.3, which are slightly higher than the values at stoichiometric concentration because of the transient effect of the explosion pipeline. The results provide a reference for selecting optimum mixing concentration in the utilization process of ULCM mixed with combustion supporting agent. The researches offer a feasible method for the utilization of ULCM, which is of great significance for energy conservation and emission reduction of CMM.