近距离煤层复合采空区煤自燃综合防治技术

Comprehensive prevention and control technology of coal spontaneous combustion in compound goaf of close distance coal seam

  • 摘要: 我国近距离煤层赋存比重大,开采时多个采空区易连通形成复合采空区。复合采空区面积大、漏风区域多、遗煤分布范围广,煤自燃灾害极为严重。针对某矿复合采空区煤自燃迅速发展、CO和C2H4大量涌出的异常情况,综合分析了复合采空区漏风源、漏风汇、地质构造、回采期间丢煤情况及煤自燃气体涌出特征等因素,确定了复合采空区煤自燃高温隐患的分布范围及发展状态,制定了隐患应急控制与隐患高效治理的“两步走”综合治理方案,采取均压与喷浆结合减少漏风、注氮惰化采空区等措施达到隐患应急控制的效果,在此基础上,划分出治理煤自燃隐患的有效措施区域,采用复合泥浆封堵、液态CO2冷却降温、三相泡沫覆盖隔氧技术实现隐患高效治理目标,构建了“堵漏控风-惰化降温-覆盖隔氧”三位一体的复合采空区煤自燃综合防治技术体系。应用上述技术后,复合采空区内C2H4体积分数由72.1×10-6降低至0,CO体积分数由3 912.6×10-6下降至20×10-6以下并保持稳定,有效消除了该矿复合采空区煤自燃高温隐患,保障了邻近工作面的安全高效开采。

     

    Abstract: In China, the occurrence of close distance coal seams accounts for a large proportion, and multiple goaf areas are easily connected to form compound goaf during mining. The compound goaf area is large. There are many air leakage areas and wide distribution range of residual coal, leading to the extremely serious coal spontaneous combustion disaster in compound goaf. In view of the rapid development of coal spontaneous combustion and the abnormal situation of CO and C2H4 pouring out from the compound goaf during the mining, this study comprehensively analyzes the factors such as air leakage source, air leakage sink, geological structure, residual coal during mining and characteristics of spontaneous combustion gas emission of coal, and determines the distribution range and development state of high temperature hidden danger of coal spontaneous combustion in compound goaf. The "two-step" comprehensive control plan for emergency control of hidden dangers and efficient management of hidden dangers is formulated. The combination of pressure equalization and leak plugging to reduce air leakage and nitrogen injection to dilute oxygen in goaf are adopted to achieve the effect of emergency control of hidden dangers. On this basis, effective measure areas of coal spontaneous combustion prevention and control are divided, and compound mud plugging, liquid CO2 cooling and three-phase foam covering oxygen isolation technology are adopted to achieve the goal of highly efficient control of hidden danger. The three-in-one comprehensive prevention and control technology system of "plugging and control velocity-inerting and cooling-covering and oxygen isolation" is constructed to completely eliminate the hidden danger of high temperature in compound goaf. After applying the above techniques, the volume fraction of C2H4 and CO in the compound goaf decreased from 72.1×10-6 and 3 912.6×10-6 to 0 and bellow 20×10-6 respectively. The results show that the proposed technology effectively eliminates the hidden danger of high temperature spontaneous combustion of coal in compound goaf and guarantees the safe and efficient mining of adjacent working face.

     

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