Study On The Spontaneous Combustion Characteristics And Hazardous Area Division Of Residual Coal In The Goaf Area Of Zhujixi Coal Mine

In recent years,more than 90%of mine fire safety accidents in China are caused by spontaneous combustion of coal,which not only causes economic losses and waste of resources to coal mines,but also threatens the life safety of underground personnel.In view of the problem of natural coal ignition in the mine in northern Anhui,it is mainly due to the lack of understanding of the spontaneous combustion characteristics of the coal seam,resulting in the unclear law of natural coal ignition in the goaf area,and the difficulty of determining the spontaneous combustion danger area,which has caused difficulties in the fire prevention and control of the mine.This paper takes the 13501 face of Zhujixi Coal Mine as the research object to study the spontaneous combustion characteristics of residual coal in the goaf area and the scope of the hazardous area of spontaneous combustion of residual coal.The 13-1seam coal samples of Zhujixi Coal Mine were collected,the experimental research on the spontaneous combustion characteristics of coal was carried out,the basic physical parameters of coal samples were determined,and the influence of particle size on the spontaneous combustion characteristics of coal was explored,and it was found that the smaller the particle size of the coal sample,the faster the oxygen consumption rate,the stronger the heat release intensity,and the stronger the natural tendency.According to the relationship between temperature and the concentration of the generated gas,CO gas was selected as the main landmark gas for the natural ignition of 13501 face coal,and C₂H₄ gas was selected as the auxiliary index gas.A total of 8 sampling measurement points and 2 thermocouples were arranged on both sides of the inlet and return air roadway of the 13501 working face,and the scope of the spontaneous combustion danger area of the abandoned coal in the goaf was divided by monitoring the change law of temperature and oxygen concentration in the goaf.The results show that the temperature reaches a maximum of 43.7°C at the side of the inlet alley 79m from the working face,and the temperature reaches a maximum of 49.6°C at the side of the return air lane 56m from the working face.The heat dissipation belt width of the inlet lane is 36m,the oxidation zone is 36-81m,and the asphyxiation zone is more than 81m;The heat dissipation belt width of the return wind lane is 27m,the oxidation zone is 27-63m,and the suffocation zone is greater than63m.And calculate that the safe propulsion speed of the working face should be greater than 2.3m/d.In order to explore the influence of nitrogen injection flow rate and nitrogen injection position on the distribution of coal spontaneous combustion hazard areas in the goaf.Based on Fluent software,a goaf geometric model is constructed,nitrogen injection into the goaf is simulated,and the simulation data results are analyzed,and it is found that nitrogen injection can effectively reduce the range of coal spontaneous combustion hazard area,and it is recommended that the nitrogen injection flow rate of this working face be set to 470m3/h.Nitrogen injection ports are set at 30m,40m,60m and 80m away from the working face,and the nitrogen injection flow rate is set to470m3/h,and the simulation results are compared and analyzed,and it is suggested that the nitrogen injection position of the working face should be set within the range of 30-40m from the working face.This paper studies the characteristics of coal spontaneous combustion in 13-1 and divides the dangerous area of coal spontaneous combustion in 13501 working face,and puts forward reasonable suggestions on nitrogen injection and fire prevention measures in this working face.Figure[36]Table[42]Reference[80]...