采空区密闭联络巷埋管抽采瓦斯技术参数优化及应用

Optimizing and application of technical parameters of gas drainage by buried pipe in closed connection roadway of gob

为解决工作面上隅角瓦斯超限难题,模拟采空区瓦斯涌出过程、工作面推进过程、采空区漏风过程,提出了采空区漏风携瓦斯有效深度及有效区域理论,根据采空区漏风携瓦斯有效深度极限值,准确合理计算工作面后方进行埋管抽采瓦斯所需采空区密闭联络巷数量。利用Fluent软件构建寺河二号井94313采空区漏风流场数值计算模型,对比工作面风量气压实测结果与数值模拟结果反演试算采空区渗透特性参数,并模拟分析了工作面推进速度与配风量对采空区漏风携瓦斯有效深度及有效区域的影响规律,采用数值分析方法构建了以工作面推进速度、配风量为自变量的采空区漏风携瓦斯有效深度极限值计算公式,引入以30 d为计算周期的实际工作面日推进速度和平均配风量计算公式,使采空区漏风携瓦斯有效深度极限值计算公式具备了现场实用性,根据每日的采空区漏风携瓦斯有效深度极限值计算结果,实时调整进行埋管抽采瓦斯的采空区密闭联络巷数量,现场应用期间采空区漏风携瓦斯有效深度极限值在142~236 m,抽采的密闭联络巷数量为2~4,上隅角瓦斯体积分数为0.18%~0.40%,研究结果表明,通过优化布置采空区密闭联络巷埋管抽采瓦斯措施能够确保上隅角瓦斯不超限,同时降低工作面配风量,提高工作面推进速度,达到安全、节能、增产的目的。

In order to effectively solve the problem of gas overrun in the upper corner of the working face,combined with the gas emission process of the gob,the working face propulsion process,and the air leakage process of the gob,the effective depth and effective area theory of air leakage carrying gas in the gob were established.The number of closed connection roadway of gob behind coal face for gas extraction by buried pipe was according to the limit value of effective depth of air leakage carrying gas in the gob.Fluent software was used to construct the numerical calculation model of air leakage flow field in No.94313 gob of Sihe No.2 Mine.The parameters of air leakage characteristics in gob were calculated by inversion of the coincidence between the measured results and the numerical simulation results of air volume and pressure changes.The influence law of advancing speed and air distribution on effective depth and effective area of air leakage carrying gas in gob was analyzed quantitatively.The calculation formula introduces the calculation formula of the daily advance speed and the average air distribution of the actual working face with the calculation period of 30 d,so that the calculation formula of the effective depth limit value of air leakage carrying gas in the gob has the practicality on the spot.According to the calculation results of effective depth limit value of air leakage carrying gas in the gob,the number of closed connection roadway of gob behind coal face for gas extraction by buried pipe was adjusted in real time.During the field application,the effective depth limit value of air leakage carrying gas in gob is142~236 m,and the number of lanes is between 2 and 4,and the gas volume fraction of the upper corner is 0.18%to 0.40%.The study results showed that by optimizing the arrangement of gas drainage in the closed contact roadway of the gob can ensure that the gas in the upper corner does not exceed the limit,reduce the air distribution in the working face,improve the advancing speed of coal face and achieve the purpose of safety,energy saving and production increase.