埋管抽采位置及负压变化对采空区煤自燃危险区域的影响

The influence of buried pipe extraction position and negative pressure change on the dangerous area ofcoal spontaneous combustion in the goaf

  • 摘要: 瓦斯抽采是治理矿井灾害常用方式之一,但在抽采过程中会增加采空区漏风量,进而增加遗煤自燃风险,直接影响采空区煤自燃危险区域分布。以中煤大同能源有限责任公司塔山煤矿30503工作面为研究对象,根据采空区实际情况建立几何模型,采用数值模拟方法分析了不同埋管抽采位置和抽采负压对采空区煤自燃危险区域的影响。结果表明:① 随着进风侧埋管抽采位置的深入,回风侧氧气体积分数呈增大趋势,而氧化带宽度变化不大;进风侧氧气体积分数整体呈减小趋势,氧化带宽度先减小后增大;采空区氧化带面积先减小后增大。② 在进风侧固定埋管抽采位置,抽采负压的变化对采空区进风侧氧气分布的影响更大,而对回风侧几乎没有影响。③ 随着抽采负压增大,进风侧氧化带宽度先减小后增大,而回风侧氧化带宽度几乎不变;采空区氧化带面积先减小后增大,氧化带面积与抽采负压呈二次函数关系。④ 最佳埋管抽采位置为采空区进风侧距离工作面20 m处,最佳抽采负压为5 000 Pa,此时采空区氧化带面积最小,即煤自燃危险区域最小。

     

    Abstract: Gas extraction is one of the commonly used methods for controlling the mine disasters. But during the extraction process, it will increase the amount of air leakage in the goaf, thereby increasing the risk of coal spontaneous combustion and directly affecting the distribution of coal spontaneous combustion dangerous areas in the goaf. Taking the 30503 working face of Tashan Coal Mine of China Coal Datong Energy Co., Ltd. as the research object, according to the actual situation of the goaf, a geometric model is established. The numerical simulation methods is used to analyze the impact of different buried pipe extraction positions and extraction negative pressure on the dangerous area of coal spontaneous combustion in the goaf. The results show the following points. ① With the deepening of the extraction position of the buried pipe on the inlet side, the oxygen volume fraction on the return side shows an increasing trend. The width of the oxidation zone does not change much. The overall oxygen volume fraction on the inlet side shows a decreasing trend, and the width of the oxidation zone first decreases and then increases. The oxidation zone area in the goaf first decreases and then increases. ② In the inlet side of the fixed buried pipe extraction position, the change of the negative pressure of extraction has a greater effect on the oxygen distribution on the inlet side of the extraction zone, while it has almost no effect on the return side. ③ As the negative pressure of extraction increases, the width of the oxidation zone on the inlet side first decreases and then increases, while the width of the oxidation zone on the return side remains almost unchanged. The area of the oxidation zone in the goaf first decreases and then increases. The relationship between the oxidation zone area and the extraction negative pressure is a quadratic function. ④ The optimal position for buried pipe extraction is at a distance of 20 m from the air inlet side of the goaf to the working face. The optimal negative pressure for extraction is 5 000 Pa. At this time, the oxidation zone area of the goaf is the smallest, that is, the coal spontaneous combustion danger area is the smallest.

     

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