Zhang Chunhua, Jiao Dengming, Zhang Min, Huang Ge
College of Safety Science and Engineering, Liaoning Technical University, Fuxin 123000, Liaoning Province, China.
College of Electronic and Information Engineering, Liaoning Technical University, Huludao 125105, Liaoning Province, China.
ACS Omega. 2022 May 11;7(20):17305-17329. doi: 10.1021/acsomega.2c01271. eCollection 2022 May 24.
Coal spontaneous combustion in gob often induces gas explosion accidents. To solve the frequent occurrence of gas and coal spontaneous combustion (GCSC) symbiotic disaster of highly gassy and spontaneous combustion-prone short-distance coal seams, the stope space of a complex working face formed by the old gob above and the coal seam mined below in Hengda Mine is divided into three zones, a completely connected zone, a partially connected zone, and an unconnected zone, according to the connectivity degree of fractures. A numerical model is established to study the relationship between gas drainage and coal spontaneous combustion. The effects of ventilation flux in the working face, gas drainage flow in the upper corner, gas drainage flow in the high-drainage roadway, fracture grout sealing, and nitrogen injection flow on the airflow field, gas concentration field, oxygen concentration field, and the temperature field in the completely connected and partially connected zones are analyzed. A multifactor interaction relationship under the conditions of ventilation, gas drainage, and nitrogen injection is revealed, and a multipoint and zoning coordinated prevention method for the GCSC symbiotic disaster is proposed. On the basis of the proposed method, the gas drainage flow in the high-drainage roadway and corner pipe of 5333(B) working face are determined to be 45.4 and 112.1 m/min, respectively, and the total nitrogen injection flow in the upper gob and the lower gob are 350 and 640 m/h, respectively. The upper corner gas concentration and the return roadway maximum gas concentration are lower than 0.8% during the stoping process, and there is no spontaneous combustion risk of the gob residual coal, thus reducing the greenhouse gas emission and realizing safety mining. This study is conducive to facilitate the realization of the goal of carbon neutrality and peak carbon dioxide emissions.
采空区煤炭自燃常引发瓦斯爆炸事故。为解决高瓦斯、易自燃近距离煤层瓦斯与煤炭自燃（GCSC）共生灾害频发问题，将恒大煤矿上方老采空区与下方开采煤层形成的复杂工作面采场空间，按裂隙连通程度划分为完全连通区、部分连通区和不连通区三个区域。建立数值模型研究瓦斯抽采与煤炭自燃的关系。分析了工作面通风量、上角瓦斯抽采量、高位抽采巷瓦斯抽采量、裂隙注浆封堵及注氮量对完全连通区和部分连通区气流场、瓦斯浓度场、氧气浓度场及温度场的影响。揭示了通风、瓦斯抽采和注氮条件下的多因素相互作用关系，提出了GCSC共生灾害的多点分区协同防治方法。基于该方法，确定5333（B）工作面高位抽采巷和隅角管瓦斯抽采量分别为45.4和112.1m/min，上隅角和下隅角总注氮量分别为350和640m/h。回采过程中上隅角瓦斯浓度和回风巷最大瓦斯浓度均低于0.8%，采空区残留煤无自燃风险，减少了温室气体排放，实现了安全开采。该研究有利于促进碳中和和二氧化碳排放达峰目标的实现。
