Abstract: Based on the cleaner production concept, we studied the technological feasibility of injecting the flue gas of power plant into the nearby goaf to prevent the spontaneous combustion of residual coal in this paper. The models of multi-component gas transport equation and heterogeneity porosity of porous media were presented, and No.92126 mechanized caving mining face in Xuecun coal mine was taken as the example for numerical calculation. The simulated results show that the maximum width of “spontaneous combustion zone” in goaf become smaller gradually with the increase of the flue gas injection rate, and the maximum width is 75 m before injecting the flue gas of power plant. The maximum width decreased to 25 m when the injected flow of flue gas is 15 m3/min. Meanwhile, the flow-field of goaf was further numerically calculated for different injection flue gas rate, and the linear regression was made for the simulated results. The dynamic equilibrium relation under the safe mining condition was obtained, and the reasonable parameters injecting the flue gas into the goaf were determined to prevent and extinguish the spontaneous combustion of residual coal in No.92126 coal face. The calculated result shows that the injection flow of flue gas should be no less than 420.15 m3/h in view of the present mining speed.

Key words: flue gas of power plant, goaf, fire prevention and extinguishing, parameters determination