Numerical Investigation For Power Plant Flue Gas Injection's Impact On Spontaneous Combustion Of Residual Coal In Goaf

As one of the major disasters in coal mine,the spontaneous combustion of residual coal in goaf seriously affects mine safety production.In fully mechanized caving face,nitrogen injection,as the main part of the comprehensive fire prevention measures,are usually used to prevent the spontaneous combustion of residual coal.In recent years,a large number of pithead power plants were built in the Coal-electricity integration construction of China.If power plant flue gas with low oxygen content can be directly injected into the underground to prevent spontaneous combustion in goaf,can reduce the energy waste of producing nitrogen,save large amounts of capitals for enterprises,and it carried out an effective way to achieve the flue gas harmlessness,reduction and resource utilization.Therefore,combine the Tashan pithead power plant and 8105 large mining height fully mechanized caving face,flue gas injection's impact on Spontaneous combustion of residual coal in goaf was studied in this paper.Based on inert gas fire extinguishing theory,from the point of sources,composition and physicchemical property,it makes a qualitative analysis on the injection quantity and inertia effect;Combined with fully mechanized sublevel caving mining mode and occurrence condition of coal seams,characteristics of spontaneous combustion hazard in 8105 working face were analyzed,and it also studied the distribution regularity of ventilation leakage and spontaneous combustion "three-zone" by the experiment measurment in a factory;According to the basic theories of hydrodynamics,the 3D multi-field coupled mathematical model of residual coal spontaneous combustion in goaf is constructed,and the method how to estimate the parameters are ascertained;Based on the contrast analysis on the actual observation data and the simulation results,the correctness of the 3d numerical model and the reliability of simulation results are proved;By using the mathematical model,the effects of different oxygen content and injecting location of flue gas on the flow fields,temperature fields and oxygen concentration fields were analyzed;Taking the maximum temperature in residual coal and the boundary location of suffocating zone as synthetical evaluation indicators,a reasonable interval of injection parameters was established.