低变质程度煤层自然发火标志气体预警值和临界值确定

Determination of Warning Value and Critical Value of Natural Ignition Marker Gas for Low Metamorphic Coal Seams

低变质程度煤层中具有较多活性基团,活性基团使煤层具有低温氧化特性,煤矿生产过程中,低变质程度煤层采煤工作面回风隅角CO体积浓度较高。为确定低变质程度煤层自然发火标志气体预警值和临界值,建立了采空区内部温度分布和回风隅角CO体积浓度预测数学模型,以122109工作面为例,利用该模型进行了测试。结果表明:回风隅角自然发火标志气体CO的预警值和临界值分别为94.4×10^(-6)、346.2×10^(-6),根据测试结果建立了煤层自然发火分级预警指标。通过案例测试表明,以采空区内部温度分布为基础的回风隅角CO体积浓度预测模型能很好地应用于低变质程度煤层。

Low metamorphic coal seams have more reactive groups,which makes them have low temperature oxidation characteristics.In the process of coal mine production,the CO concentration is higher in the return air corner of low metamorphic coal seams is relatively high.In order to determine warning value of natural ignition marker gas and critical value for low metamorphic coal seams,establishes the temperature distribution model inside the mining area and the prediction model of CO volume concentration in the return air corner.Taking 122109 working face as an example,uses the model to conduct tests.The results show that the warning value and the critical value of CO in the return air corner are 94.4×10^(-6) and 346.2×10^(-6),respectively.Based on the test results,establishes a graded warning index management system for natural fire in coal seams.Case testing shows that the prediction model can be well applied to the CO volume concentration in the return air corner based on the internal temperature distribution in low metamorphic coal seams.