基于正压密封方法的闭式采空区灭火技术

On the closed-type goaf fire extinguishing technology based on the application of the positive pressure sealing method

为提高闭式采空区密闭漏风控制效果,基于矿井空气流动基础理论,运用RFPA软件建立了注氮气室正压密封采空区数值模型,模拟分析了注氮气室正压作用对采空区密闭漏风行为的影响规律,提出了基于注氮气室正压密封方法的采空区灭火技术,并在恒大煤矿5333工作面采空区进行了应用。结果表明,在气室内氮气相对正压作用下,通风巷道向采空区漏风速度快速减小至0,并最终产生反向,形成由气室向外部微量漏氮气的状态,5333采空区采取正压密封方法后,内部CO、C2H4和温度快速消失和降低至安全范围值。

The present paper is aimed at introducing its study on the positive pressure sealing method oriented for the closed goaf fire extinguishing. For our research purpose,we have established a numerical model of positive pressure controlling air leakage at the goaf sealing wall via a software known as RFPA based on the coal-mining air ventilation theory. The above mentioned positive pressure can be produced by continuously injecting nitrogen into a sealing chamber framed by the two sealing walls outside the goaf. On the basis of our simulated work,we have made a systematic analysis on the influence of the nitrogen pressure increase of the air leakage consequence. In addition,we have also developed a positive pressure sealing technology which is mainly advantageous for its nitrogen injection chamber and the sand column sealing wall outside the goaf. What is more,the aforementioned technology has also been applied to No. 5333 goaf in Hengda Coal Mine.For the period of our experimentation,we have also recorded the gas index and the temperature degree,the two key parameters for evaluating the fire extinguishing means. Thus,the above said simulation models we have proposed show that the air leakage speed from the roadway to the goaf has been quickly made to drop to zero with the increase of the nitrogen pressure in the chamber,which has promoted the change of the nitrogen leakage from the chamber to the outer roadway and the inner goaf. Thus,it can be concluded that due to the use of the goaf fire extinguishing field,the temperature quickly has been made to drop to below 30 ℃. At the same time,the goaf gas drainage pressure has been made to the negative one of 300- 500 Pa,with the flowing rate being at 50-60 m3/ h and the gas volume fraction being at91%,so that the nitrogen injection flow rate can be made to be kept at0. 15 m3/ min and the positive pressure at 10- 20 Pa. And,in so doing,it would be possible for CO and C2H4 soon to disappear,and,getting finally rid of the coal spontaneous combustion potential danger of the goaf.