Gong-kuang zidonghua (Sep 2021)
Experimental study on ignition of methane and coal dust on the surface of high temperature heat source
Abstract
The high temperature area of coal spontaneous combustion in coal mine goaf may cause methane/coal dust explosion. Therefore, it is necessary to carry out research on coal spontaneous combustion induced methane/coal dust explosion. The current research on the characteristics of methane/coal dust explosion based on the electric spark induced method cannot fully reflect the characteristics of methane/coal dust explosion induced by coal spontaneous combustion in the goaf. In order to solve this problem, the self-developed 40 L gas explosion equipment is used to study methane/coal dust explosion characteristics under the high temperature surface ignition of heat source. The results are showed as follows. ① The methane/coal dust explosion process obtained by the surface ignition method of the high-temperature heat source is consistent with that of methane/air explosion, which can be divided into 3 stages. ② The three explosion parameters of methane/coal dust (explosion pressure, pressure rise rate and explosion temperature) are consistent with the change law of methane concentration, that is, the parameters first increase with the increase of methane concentration, reach a peak and then decrease with the increase of methane concentration. When the methane concentration is less than the turning concentration, the three explosion parameters of methane/coal dust are greater than the corresponding explosion parameters of methane/air respectively. When the methane concentration is greater than the turning concentration, the three explosion parameters of methane/coal dust are less than the corresponding explosion parameters of methane/air respectively. Due to the addition of coal dust, the turning concentrations of the three explosion parameters of methane/air decrease from 11.5% to 9.5%, 10.5% and 9.5% respectively, and the peak values increase by 0.8%, 6.9% and 0.8% respectively, and decrease regularly. ③ Due to the different ignition methods, the explosion temperature change law is different. The explosion temperature rises again in the falling stage (stage III) after the methane/coal dust is detonated by the electric spark. The explosion temperature change law after detonation of methane/coal dust on the surface of high-temperature heat source remains the same as that before the addition of coal dust. ④ The coal dust ignition temperature prediction function is corrected, and the goodness of fit is improved by 20.05% after correction. Combined with the experimental data, the ignition temperature prediction function of coal dust in the ignition mode of the high temperature heat source surface is obtained.
Keywords
