张双楼煤矿回撤工作面自然发火预警标志气体及临界值确定

Determination of Gas and Critical Value as Early Warning Sign of Spontaneous Combustion in Withdrawal Face of Zhangshuanglou Coal Mine

张双楼矿7201边界工作面总回撤时间超过煤层最短自然发火周期,为确定边界工作面煤自燃主控因素、煤层自然发火标志气体及其预警临界值,通过统计采空区遗煤分布、煤孔裂隙、围岩变形、含水率及采空区漏风等容易引起煤自燃的参数,得出工作面自燃的煤层孔裂隙发育及采空区漏风为主控因素;建立了煤升温氧化过程中标志性气体温度与浓度的关系,提出CO增加速率与烯烷比为辅助指标判断煤自燃的预警指标。研究发现煤温度80~90 ℃之间时煤体CO产生速率发生了突变,得出回撤工作面遗煤的临界自燃温度为80~90 ℃。

The total withdrawal time of the 7201 boundary working face of Zhangshuanglou Coal Mine exceeds the shortest spontaneous combustion period of the coal seam,in order to determine the main controlling factors of coal spontaneous combustion in the boundary working face,the sign gas of coal seam spontaneous combustion and its early warning critical value.Through the statistics of the natural parameters of coal,such as the distribution of residual coal in goaf,coal hole crack,surrounding rock deformation,water content and air leakage in goaf,it is concluded that the development of coal seam hole crack and air leakage in goaf are the main controlling factors,the relationship between temperature and concentration of sign gas in the process of coal heating and oxidation is established,and the early warning index of coal spontaneous combustion is judged by CO increasing rate and olefin / alkane ratio.It is found that the CO production rate of coal has a sudden change when the coal temperature is 80-90 ℃,and it is concluded that the critical spontaneous combustion temperature of the residual coal in the withdrawal face is 80-90 ℃.