注氮条件下瓦斯抽采对采空区自燃“三带”的影响

Gas Drainage Affected to Spontaneous Combustion Three Zones of Mining Goaf Under the Condition of Nitrogen Injection

为了解决高抽巷抽采引起采空区漏风量增加导致采空区遗煤自燃倾向增大的问题,针对正行煤矿1502综放工作面开采具有高瓦斯易自燃的特点,采用现场实测与数值模拟相结合的方法,通过Fluent软件模拟了采空区未采取注氮和抽采措施、高抽巷抽采和注氮条件下高抽巷抽采等3种情况的采空区瓦斯浓度场、漏风场、氧气浓度场的变化情况,得出了采空区自燃'三带'分布范围:散热带0~23 m,氧化带23~69 m,大于69 m为窒息带;将采空区自燃危险性区域确定为23~69 m。根据以上结果,对注氮效果、抽采负压进行评价,完善了采空区在注氮条件下高抽巷抽采防灭火系统。

In order to solve a spontaneous combustion risk increased problems of coal left in goaf caused by air leakage quantity increased in the goaf due to gas drainage in a high level gas drainage gateway,according to high gassy and easy spontaneous combustion features of the mining operation in No. 1502 fully- mechanized top coal caving mining face in Zhengxing Mine,a combined method with a site measurement and a numerical simulation was applied to simulate a gas concentration field,air leakage field and oxygen concentration field in the goaf occurred in three high level gas drainages under the conditions of no nitrogen injection and gas drainage measures,gas drainage in the high level gas drainage gateway and nitrogen injection in the goaf with Fluent software. With the Fluent simulation technology,three zones distribution in the goaf could directly obtained with a heat radiation zone of 0 ~ 23 m,oxidation zone with 23 ~ 69 m and suffocation zone over 69 m. A spontaneous combustion danger area in the goaf was determined as 23 ~ 69 m. Finally,an evaluation was conducted on the nitrogen injection effect and gas drainage negative pressure and a fire prevention and control system of the gas drainage in the high level gas drainage gateway under the nitrogen injection condition of the goaf was improved.