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火成岩影响区CO异常涌出机理及预测研究

Study on mechanism and prediction of CO abnormal emission inigneous rock intrusion area

  • 摘要: 为探究火成岩影响区CO涌出原因及预测技术,火成岩入侵中高温作用对煤结构、自然氧化能力的影响,以模拟热环境和实际火成岩影响区煤样结合的方法进行试验研究。采用了不同温度预处理煤样模拟岩浆侵入热变质作用,进行了压汞试验和煤体CO吸附试验以探究热环境对煤变质、CO吸附和孔隙结构的影响;选用林南仓矿距火成岩入侵距离不等的3个工作面煤样进行对比试验,分别进行了程序升温、红外光谱、热重等试验来探究煤体CO释放规律及其升温氧化原因分析,确定了林南仓矿火成岩影响区CO赋存情况及其自然发火预测指标。结果表明,在试验温度(300 ℃)下,热作用是煤体煤阶升高的主要原因,温度升高可使煤中微孔和大孔数量增加,煤体表面积和孔容相应增加,孔隙连通性增强;程序升温试验中,林南仓矿距火成岩入侵距离小的煤样能更早进入剧烈氧化阶段,更容易在较低温度释放大量CO,因此可以判断火成岩入侵造成的高温环境改变煤体结构(煤体孔容增加、孔隙连通性增强),从而提高了煤体吸附CO的能力和自然氧化中氧气与煤体接触的能力;提出以φ(CO2)/φ(CO)浓度比值作为林南仓矿的自然发火预测指标,解决了现场回采工作面自然发火的预报预测难题,对同类矿山煤自燃的防治有较高的应用价值。

     

    Abstract: In order to explore the causes and prediction techniquesof CO emission in igneous rock intrusion area,and the effect of high temperature on coal structure and natural oxidation capacityduring igneous rock intrusionis studied by simulating the combination of thermal environment and coal samples in actual igneous rock affected area. The coal samples with different temperature pretreatments were used to simulate the magmatic intrusion of thermal metamorphism, and mercury intrusion experiments and coal CO adsorption tests were carried out to investigate the effects of thermal environment on coal metamorphism, CO adsorption and pore structure. The coal samples from three working face with different igneous rock intrusion distances were selected for comparative experiments. Temperature rise programming, infrared spectroscopy, thermogravimetry and other tests were carried out to investigate the CO release law of coal and the cause of temperature rise oxidation.The occurrence of CO in the igneous zone affected by Linnancang mine and its natural ignition prediction indexwere determined. The test results show that at the experimental temperature (300 ℃), the thermal action is the main reason for the increase of coal rank. The increase of temperature can increase the number of micropores and macropores in coal, and increase the surface area and pore volume of coal, and the pore connectivity is also enhanced;Coal sample closed to the igneous rock intrusion is easier to release a large amount of CO at a lower temperature, and it is more likely to enter the violent oxidation stage.Therefore, it can be judged that the high temperature environment of the igneous rock intrusion increases the capacity of the coal body and enhances the pore connectivity.The way of changing the structure of coal body improves the ability of CO to be attached to coal and the ability of oxygen to contact with coal in natural oxidation.It is proposed to use φ(CO2)/φ(CO) as a natural ignition prediction index for Linnancang mine.This indicator solves the problem of forecasting natural fire on site and has a high application value for coal spontaneous combustion control of similar coal mines.

     

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