突出矿井近距离煤层群煤自燃预警与防控方法

Early warning and control methods of coal spontaneous combustion in close distance coal seams in outburst mines

突出矿井煤层群存在开采过程互相影响,采空区贯通,漏风地点较多,防灭火工作难度大等特点。为了对突出矿井近距离煤层群煤自燃过程进行准确预测,以贵州发耳煤矿为例,通过煤自燃程序升温试验分析了煤氧化过程中各气体的变化规律,确定了煤自燃单指标气体和标志气体比值的综合预测指标,提出了煤自燃监测预警系统和现场布置情况。结果表明:发耳煤矿各煤层煤样的临界温度范围为70~80℃,干裂温度范围为130~140℃。结合耗氧情况、CO和C_(2)H_(4)的出现温度和变化规律综合判定得到发耳煤矿不同煤层煤自燃氧化优先级顺序为:1#煤>3#煤>5-2#煤>5-3#煤>10#煤>7#煤。根据试验结果和现场数据,确定了煤自燃温度的6个气体指标(CO、O_(2)、C_(2)H_(4)、φ(CO)/φ(CO_(2))、φ(CO_(2))/φ(O_(2))、φ(CO)/φ(O_(2)))及分级预警的温度范围和气体指标临界值,对煤自燃进行四级分级预警。最后,提出了针对突出矿井煤层群“加强煤自燃预测预报、注氮防灭火、动态推进、堵漏风或注凝胶/高分子胶体”的煤自燃分级防控方法,有效解决了突出矿井煤层群煤自燃预警与防控问题。

The coal seam group in the outburst mine has the characteristics of mutual influence in the mining process,the goaf is connected,there are many air leakage places,and the fire prevention work is difficult.In order to accurately predict the coal spontaneous combustion process of the coal seam group near outburst mines,taking Guizhou Fa’er Coal Mine as an example,the variation law of each gas during the coal oxidation process was analyzed through the coal spontaneous combustion temperature programmed experiment,the comprehensive prediction indicators of the coal self-combustion single index gas and the marked gas ratio were determined,and the coal spontaneous combustion monitoring and early warning system and the field layout were proposed.The results show that the critical temperature range of each coal seam in Fa’er Coal Mine is 70-80℃,and the dry cracking temperature range is 130-140℃.Combined with the oxygen consumption,the occurrence temperature and change law of CO and C_(2)H_(4),the priority order of spontaneous combustion oxidation of different coal seams in Fa’er Coal Mine is:1#coal>3#coal>5-2#coal>5-3#coal>10#coal>7#coal.According to the experimental results and field data,six gas indexes(CO,O_(2),C2H4,φ(CO)/φ(CO_(2)),φ(CO_(2))/φ(O_(2)),φ(CO)/φ(O_(2)))of coal spontaneous combustion temperature and the temperature range and gas index critical value of graded early warning were determined,realizing the four grades early warning of coal spontaneous combustion.Finally,a grading prevention and control method for coal spontaneous combustion is proposed for outburst coal seam groups,such as“strengthening coal spontaneous combustion prediction and forecasting,nitrogen injection to prevent and extinguish fires,dynamic advancing,air leakage plugging,or gel/polymer colloid injection”,which effectively solves the problem of early warning and control of coal spontaneous combustion in coal seam groups in outburst mines.