Experimental study to assess the explosion hazard of CH4/coal dust mixtures induced by high-temperature source surface

The explosion accident caused by the spontaneous combustion surface of coal after the coal dust is rolled up by the gas gushing from the goal seriously threatens the safety of coal coal mining. Based on this hazard, self-developed gas explosion equipment is used to detonate the CH4/coal dust mixture by high-temperature source. The process and mechanism of gas/coal dust explosion induced by coal spontaneous combustion in goaf were simulated, and its risk was evaluated. It is of great significance to understand the initiation mechanism of gas-solid mixture through coal spontaneous combustion in goaf. The results show that the explosion pressure (Pgd), explosion temperature (Tgd), rate of pressure rise ((dP/dt)gd), and explosion index (K) of CH4/coal dust mixtures are closely related to the temperature of high-temperature source and volatile content. The role of coal dust volatiles in homogeneous and nonhomogeneous reactions was revealed. Combined with three explosion parameters (Pgd, Tgd, K), the most dangerous explosion combination concentration of the selected CH4/coal dust mixture is (9.5 %, 500 g/m(3)), (9.5 %, 400 g/m(3)), and (8.5 %, 500 g/m(3)) at 1073 K ignition temperature. The involvement of coal dust leads to a lower explosion limit for CH4/air. The Jiang model has better applicability to the prediction of lower explosion limits for CH4/coal dust mixtures induced by the high-temperature source surface. (C) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

This study evaluated the risk of gas/coal dust explosion induced by coal spontaneous combustion in goaf, finding that explosion parameters are closely related to the high-temperature source temperature and volatile content. The involvement of coal dust lowers the explosion limit for CH4/air.