近距离煤层工作面上覆采空区注液氮防灭火效果研究

Study on Fire Extinguishing Effect of Liquid Nitrogen Injection in Overlying Goaf of Close Distance Coal Seams

近距离煤层赋存条件下工作面在回采过程中,受负压通风作用,上覆采空区部分温度异常区域的高浓度CO等有害气体通过采动裂隙侵入工作面,通过采取在地面部分高温区域范围沿工作面倾向设计合理治理钻孔对工作面上覆区域实施预防性动态交替式注液氮措施,使得异常区域温度、有害气体浓度得到有效控制。结果表明:注氮后所有钻孔温度呈大幅下降趋势、CO气体浓度呈先升高后不断降低趋势,治理区域效果明显,短期内未见明显反弹迹象,能确保工作面实现安全生产。

Under the condition of occurrence of close coal seams in the process of mining and the effect of negative pressure ventilation,the high concentration of CO and other harmful gases in the overlying goaf temperature abnormal area intrude into the working face through mining-induced fractures.In order to effectively control the abnormal area temperature and the concentration of harmful gases,the measures of preventive dynamic alternating liquid nitrogen injection were adopted to control the drilling hole along the working face inclination in the high temperature area.The results showed that after nitrogen injection,the temperature of all boreholes showed a significant downward trend,and the concentration of CO gas increased first and then decreased continuously.The effect of regional treatment was obvious,and there was no obvious rebound sign in the short term,which could ensure the safe production of the working face.