综放采空区二氧化碳防灭火参数确定

Determination of parameters of injecting CO_2 to prevent spontaneous combustion in gob of fully mechanized top-coal caving workface by means of numerical modeling

为了实现快速惰化采空区抑制煤氧化而解决针对煤层自燃火灾的防灭火参数问题,采用数值试验方法,通过建立综放采空区注二氧化碳条件下渗流场和浓度场的三维模型,研究了注二氧化碳口不同位置、不同流量时综放采空区自燃"三带"的分布规律。结果表明:最佳注二氧化碳口位于进风顺槽距工作面约20m的采空区,注二氧化碳后氧化升温带最大宽度由进风侧移动到工作面中部,随注二氧化碳流量增加,采空区氧化升温带的最大宽度近似呈线性降低,据此提出了注二氧化碳最小流量的计算方法。该成果对煤层自燃火灾的防治具有一定的参考价值和指导意义。

The parameters for preventing spontaneous combustion in coal seam was studied by speediness inerting gob and suppressing coal exidation. Adopting method of numerical experiment, a 3D model defining flow and concentration field in gob of fully mechanized top-coal caving workface on condition of injecting CO2 is developed. Different position of CO2 inlet and CO2 injecting flux are studied by means of numeric modeling. The result proves that the best inlet position lies in the air inlet side of the gob 20m away from the workface; the widest position of self-heating zone moves from the inlet side to the middle of the workface; the largest width of self-heating zone decreases linearly as CO2 injecting flux increases. A formula to calculate the smallest CO2 injecting flux is put forward accordingly.