Research On Property Of Coal Low Temperature Oxidation And Technology Of Preventing And Controlling Spontaneous Combustion In The Goaf Of Fully Mechanized Working Face Of Xieyi Mine

The5121(3) fully mechanized coal mining face of Xieyi coal mine is the outburst coal seam and the amount of gas emission is larger. Because of5111C13and5111(3) working face on the upper stage and overlying5121C15and5111C15coal seam having been excavated, the working face easily link to the goaf of the adjacent layers. In order to prevent gas accident, the air volume is large in the mining process, so air leakage of goaf tends to be more serious. And the scope of "three zone" of goaf changes over the intensity of air leakage, which increase the scope of hazard area of goaf. The residual coal of goaf is more for the low recovery, and once the working face spontaneous combustion, it is difficult to determine the fire position and extinguish the fire hazard due to air leakage of goaf of the adjacent layers being serious.This paper systematically study the spontaneous combustion characteristic of residual coal of5121(3) working face of Xieyi coal mine through the method of theoretical analysis and experimental research, numerical simulation and field measurement. The paper takes the low-temperature oxidation of coal experiment as the starting point, regards the total oxygen consumption rate, heat flux, heat release and characteristic temperature as the main parameters of coal low temperature oxidation, analyzes the low-temperature oxidation law of the different water content and different sizes of coal samples, and elects index gas CO, C3H8and C2H4of the spontaneous combustion of residual coal in goaf. Combined with porous medium and seepage flow mechanics theory, the three-dimensional mathematical and physical model of goaf is established by the application of Fluent simulation software, and the distribution of "three zone" of goaf under the condition of different air quantity is analyzed on the basis of division index of air leakage of goaf. According to the site conditions of5121(3) working face, the beam tube was embedded in the intake and return air roadway to acquire the oxygen concentration in each measuring point, and then sum up the practical distribution of "three zone" of goaf. The early forecasting system of coal spontaneous combustion and the comprehensive fire-fighting system was established by relying on them in the goaf of5121(3) fully mechanized coal mining face. Once the occurrence of spontaneous combustion index gases was monitored, they will immediately start the comprehensive fire extinguishing system with nitrogen injection and grouting to ensure the safe production of working face.