烟道气预防采空区自燃的数值模拟及参数确定

Numerical simulation and parameter determination in goaf spontaneous combustion prevention by injecting flue gas

基于清洁生产的理念,对坑口电厂烟道气就近注入采空区以防止遗煤自燃技术的可行性进行研究。通过建立多组分气体流动模型及多孔介质非均质孔隙率模型,并以薛村矿92126综放工作面为实例进行了数值计算。模拟结果显示随着注气量的加大采空区"自燃氧化带"最大宽度逐渐变小,注气前最大宽度为75 m,以15 m3/min注入采空区后自燃氧化带最大宽度减小为25 m。对不同注气量下采空区流场进行了数值计算,并对结果进行了线性回归,得出了安全回采下的动态平衡关系,确定了92126工作面采空区注烟气防灭火参数,经计算现回采速度下烟气注入量应不低于420.15 m3/h。

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 calcu lated 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.