【作者】 常绪华；

【导师】 王德明；

【作者基本信息】 中国矿业大学 ， 安全技术及工程， 2013， 博士

【摘要】 采空区瓦斯燃烧是煤矿多发事故之一，随着煤矿开采水平的加深，瓦斯涌出和地温不断增加，这使得自燃诱发瓦斯燃烧成为一种重要的形式。由于缺少自燃条件下瓦斯燃烧发生规律和防治研究，使得现场防治自燃引燃瓦斯时具有一定的盲目性，为此，本文重点对采空区煤自燃诱发瓦斯燃烧的规律及防治进行了研究，研究结果有利于减少采空区瓦斯燃烧事故的发生。为了控制采空区煤自燃诱发瓦斯燃烧，基于矿压理论对采场自燃和瓦斯涌出规律进行了研究。分析了采场应力分布，得出采煤过程中在采场走向和倾向上会逐渐形成应力“三区”，这造成了上覆岩层在垂直方向上逐渐形成冒落三带和在采空区冒落带形成“O”型压实区，此种岩层冒落规律使得采空区见方前形成了“U”型漏风，见方后形成了“M”型漏风。把采场易自燃区域分为煤柱附近、断层附近、大矸石处等，结合采场瓦斯涌出规律，提出控制漏风和浮煤分布是减少自燃诱发瓦斯燃烧的有效手段。在分析自燃引燃瓦斯理论的基础上，论文设计加工了高温煤体引燃瓦斯实验平台，开展了高温煤体诱发瓦斯燃烧实验。研究了不同加热功率、初始CH₄浓度和热源深度条件下煤样升温过程中封闭空间气体的变化规律，结果显示，随温度升高，封闭空间O₂浓度降低，N₂浓度先增大后减少，其他气体浓度增加。在高温阶段，加热功率增大使得O₂浓度增大，N₂浓度先增大后减小，其他气体浓度减小；增大初始CH₄浓度，O₂浓度先减小后增大，CH₄浓度增大，其他气体浓度减小；当热源深度增加时，O₂浓度增大，N₂浓度先减小后增大，其他气体浓度减小。利用Matlab对煤样升温过程中封闭空间可燃气体浓度与其爆炸限之间的关系进行了分析，得到在多数条件下，封闭空间可燃气浓度会大于其爆炸上限而失去爆炸性。结合现场煤自燃形式，指出了工作面煤柱、顶煤和上邻近煤层提前氧化区域在压裂或冒落进采空区时易引燃瓦斯。为了得到上隅角不同空间特性下瓦斯燃烧规律，基于上隅角瓦斯燃烧实验平台，设计了自由空间、充填矸石、瓦斯包和风扇干扰条件下的瓦斯燃烧实验，通过高速摄像和测温系统记录燃烧过程和温度，分析了不同条件下的CH₄燃烧过程，得到了自由空间下7.8%和21%瓦斯燃烧速度较慢，从而提出了现场可能存在低浓度和高浓度瓦斯燃烧；充填矸石使得瓦斯不易引燃，但引燃后燃烧速度加快和强度增强，易形成爆炸；瓦斯包燃烧时，燃烧波的多次叠加增加了爆炸的破坏性；风扇干扰条件下，瓦斯不易引燃，但引燃后燃烧速度加快，且风扇干扰使瓦斯燃烧易在矸石内部传播，增加了扑灭瓦斯燃烧的困难度。对瓦斯燃烧时间和条件的关系进行了分析，得出了自由空间初始阶段瓦斯燃烧速度为几到几百厘米每秒；对不同条件下瓦斯燃烧温度进行定性分析，验证了瓦斯燃烧的传播过程。为了保证6135试验工作面顺利回采，开展了现场煤自燃诱发瓦斯防治研究。通过气体和温度观测，验证了机巷煤柱和上邻近煤层为该工作面自燃引燃瓦斯区域。针对“Y”型通风方式，在模型假设和连续定量稳定释放SF6的基础上建立了工作面漏风定量计算模型，开展漏风测试，得出了该工作面下隅角向采空区漏风较大，漏风率为-23.35%。基于数值模拟技术对6135采空区自燃“三带”和瓦斯爆炸浓度范围进行模拟，得到了易发生自燃引燃瓦斯的区域。针对试验工作面自燃危险区域，提出了预注阻化液、注三相泡沫和液态CO₂等措施进行防灭火，结果显示，对60煤预注阻化液可以很好的预防上邻近煤层的自燃问题；大量灌注三相泡沫和液态CO₂很好的控制了机巷自燃点，保证了工作面顺利开采和收作，取得了很好的经济效益。更多还原

【Abstract】 Gas burning is one of multiple accident in coalmine goaf. With the increase ofmining depth, gas emission and ground temperature are increased continuously. Thismakes gas burning induced by coal spontaneous combustion become an importantform. Due to the lack of gas burning law and prevention research under the conditionof spontaneous combustion, it has certain blindness to prevent gas burning frominducing by spontaneous combustion in field. Therefore, this paper focused onresearching the law and prevention of coal spontaneous combustion inducing gasburning in goaf. The result is beneficial to decrease the occurrence of gas burning ingoaf.In order to control coal spontaneous combustion inducing gas burning in goaf,law of spontaneous combustion and gas emission in stope was studied based on minepressure theory. On the basis of analyzing stress distribution in stope, stress “threeareas” is gradually formed in strike and tendency of stope during coal mining isobtained. This results in the formation of overlying strata caving “three zones” invertical direction and O-ring recompaction area in caving zone of goaf. The stratacaving law leads to “U” type air leakage before becoming a square of goaf and “M”type air leakage after becoming a square of goaf. Easy self-ignition area is dividedinto the vicinity of coalpillar, fault and large gangue. Based on the gas emission ofstope, effective means of decreasing spontaneous combustion inducing gas burning,controlling air leakage and residual coal distribution, are proposed.On the basis of analyzing spontaneous combustion igniting gas theory,experiment platform of high temperature coal igniting gas was designed andconstructed and experiment of high temperature coal inducing gas burning wascompleted. Closed space gas change law during coal warming was studied underdifferent heating power, different initial CH₄concentration and different heat sourcedepth. The results showed O₂concentration decreases, N₂concentration increases firstand then decreases and other gas concentration increases with the increase of closedspace coal warming. In the high temperature stage, O₂concentration increases, N₂concentration increases first and then decreases and other gas concentration decreaseswith the increase of heating power. O₂concentration decreases first and then increases,CH₄concentration increases and other gas concentration decreases with the increaseof initial CH₄concentration. O₂concentration increases, N₂concentration decreases first and then increases and other gas concentration decreases with the increase of heatsource depth. Relation between closed space gas concentration and explosion limitduring coal warming process was analyzed by Matlab. The result shows closed spacegas concentration is greater than its explosion limit and easily loses explosiveness inmany conditions. Advancing oxidation area of coalpillar, top coal and upper adjacentcoal seams is easy to ignite gas during crushing or caving in goaf was proposed bycombining with spontaneous combustion form in field.In order to obtain gas burning law of different spatial characteristic in uppercorner, gas burning experiment of free space, filling gangue, gas package and faninterference was devised based on gas burning experiment platform. Burning processand temperature were recorded by high-speed camera and temperature measuringsystem. Burning process of CH₄burning under different conditions was analyzed. Theresult shows the burning speed of7.8%and21%gas concentration under free space isslower. Low and high concentration gas burning are possible to occur is proposed.Gas of filling gangue is not easy to ignite. But the burning speed and strength becomestronger after being ignited and burning is easy to become explosion. When gaspackage is ignited, explosive destructiveness is increased because of the superpositionof combustion wave. Gas is not easy to ignite under fan interference. But the burningspeed becomes quicker and is easy to spread in gangue inside. This increases thedifficulty of putting out gas burning. Relation of gas burning time and condition wasanalyzed. The result shows gas burning speed of initial moment in free space is a fewto a few hundred centimeters per second. Qualitative analysis of gas burningtemperature under different conditions was done and gas burning spread process wasproved.Prevention research of coal spontaneous combustion inducing gas burning infield was completed in order to ensure6135test face smoothly mining. Machine-lanecoalpillar and upper adjacent coal seam were the area of spontaneous combustionigniting gas in this face was proved by gas and temperature observation. According tothe "Y" type ventilation, the quantitative calculation model of air leakage in face wasestablished based on model hypothesis and continuous quantitative stable release SF6.Air leakage test was done and the result shows air leakage volume in lower corner ismore large and the air leakage rate is-23.35%. Based on numerical simulationtechnology, range of spontaneous combustion “there zones” and gas explosionconcentration was acquired in6135goaf. The region where gas was frequently ignited by coal spontaneous combustion in this face was obtained. According to the dangerzone of coal spontaneous combustion, the fire prevention and extinguishing measuressuch as pre-injecting inhibitor, three-phase foam and liquid CO₂were proposed. Theresult shows pre-injecting inhibitor can prevent60coal from spontaneous combustionand large perfusion three-phase foam and liquid CO₂can control machine-lanespontaneous combustion point. Measures made the face smoothly mining andrecovery and good economic benefits were achieved.更多还原