侏罗纪煤层井工开采自燃机理及火区探测技术基础研究

Huge Jurassic coal reserves in Northwest China accounts for 39.6% of the total coal resources formed in each coal-forming period. There's a big difference between the spontaneous combustion tendency of Jurassic coal and Carboniferous - Permian coal in middle-east China, and spontaneous combustion of Jurassic is generally serious. Goaf fire source positioning is the key of extinguishing, and always the emphasis and difficulty in spontaneous combustion research. On the basis of coal oxygen compound theory, we can take Jurassic coal low temperature oxidation experiment, oxygen uptake experiment and functional group determination experiment, and then we can make a comprehensive analysis of the dynamics of the low-temperature oxidation of coal, each functional group content and its influence on the spontaneous combustion performance. Finally we can get the Jurassic coal spontaneous combustion mechanism and characteristics. We can find out the law of spontaneous combustion of underground mining Jurassic coal through the determination of temperature, gas composition and concentration of goaf. We can establish the flow field model of underground mining, the temperature field and the main gas components field model by the law of conservation of mass and energy conservation law, Darcy's law and Fick's law, and compose the mathematical model of spontaneous combustion of coal seams. We can know the actual temperature of goaf boundary by optical fiber temperature measurement, then use mathematical model to solve the temperature distribution of goaf area, and get the goaf fire area. Research results in this project are of paramount significance to prevent spontaneous combustion of the Jurassic coal seam, ensure normal and safe production of mine enterprises and enhance their economic profits.

我国西北地区侏罗纪煤炭资源储量巨大，占我国各成煤时代煤炭资源总量39.6%。侏罗纪煤自燃情况普遍严重，且与我国中东部的石炭-二叠纪煤自燃倾向性差别较大。采空区自燃火源定位是灭火的关键，也是煤层自燃研究重点和难点。依据煤氧复合理论，进行侏罗纪煤层低温氧化实验、吸氧量实验和官能团测定实验，综合分析煤的低温氧化动力学特性、各官能团含量及其对自燃性能的影响，得出侏罗纪煤层自燃机理和特点。通过采空区温度、气体成分及浓度的测定，找出井工开采侏罗纪煤层自燃规律。由质量守恒定律、能量守恒定律、达西定律和菲克定律建立开采的流场模型、温度场及主要气体成分场模型，组成煤层自然发火数学模型。利用光纤测温得出采空区内边界实际温度，再运用数学模型解算采空区内温度分布，导出采空区火区范围。本项目研究成果，对预防控制侏罗纪煤层自燃、保证煤矿企业正常安全生产提高经济效益有十分重要意义。

现今侏罗纪煤层的研究主要集中在煤层地质学、研究煤岩性质等，关于侏罗纪煤层自燃现象研究较少，往往只是从防灭火的角度出发，而较少研究其自燃机理。本项目从侏罗纪煤的煤岩特性出发，选取侏罗纪煤样：陕西省神木县神东集团大柳塔矿煤样、鄂尔多斯市察哈素煤矿煤样、包头市东部杨圪楞矿业前坝二号井煤样和内蒙古阿拉善盟松树滩煤矿煤样，石炭纪煤样：江苏姚桥矿石炭纪煤样和山西常村矿石炭纪煤样，为实验煤样，通过一系列侏罗纪煤样工业分析、静态吸氧量、程序升温气体生成、红外光谱官能团测定和差示扫描量热等煤自燃相关实验研究，以煤自燃学说（煤氧复合学说）为基础，研究了侏罗纪煤样的煤质特性、侏罗纪煤自燃倾向性及自燃倾向性大小，主要官能团的变化规律及其氧化反应中的微观特性、煤样氧化燃烧过程中的热效应随温度的变化关系、蒙西侏罗纪煤样氧化自燃过程中的特征及动力学参数等等。结合理论分析，得出侏罗纪煤层自燃机理。在侏罗纪煤层自燃机理和建立组成煤层的自然发火数学模型的井工开采流场模型、温度场及主要气体成分场模型的基础上，选取典型侏罗纪煤矿察哈素煤矿和大柳塔矿工作面采空区，分析侏罗纪煤采空区自燃主要影响因素，研究了侏罗纪煤层采空区自燃规律。在侏罗纪煤老石旦矿采空区中布设光纤测温系统，得到采空区回风侧边界的真实温度，根据采空区的具体条件运用建立的自然发火数学模型进行解算，得出了采空区内的温度分布，从而得到采空区自然发火状况。通过对侏罗纪煤层煤自燃机理及火区探测技术研究，完善了侏罗纪煤层自然发火机理相关研究，同时对提高侏罗纪煤层井工开采自燃预报、检测、控制，保证煤矿企业正常安全生产，确保矿工生命安全、保护资源、净化环境，具有重要的科学意义。