低变质煤CO来源及防控技术研究

Study on CO source and control technology of low metamorphic coal

为了研究低变质煤CO来源,降低煤层自然发火风险;以大南湖一矿3#煤层为研究对象,通过程序升温实验、实验模拟及现场观测等手段,研究3#煤层CO赋存、开采及割煤中CO产生规律及回风隅角CO来源占比等规律。结果表明:煤在无氧下粉碎,煤分子共价键断裂生成的大量官能团、自由基相互作用产生极少量CO;煤在有氧下粉碎,产生大量CO,随煤样比表面积增大,CO体积分数随之增加并最终趋于稳定;采煤机割煤中产生高温使煤体发生氧化产生CO体积分数为(30~50)×10^(-6);回风隅角CO来源于采空区的CO体积分数占回风隅角CO总体积分数的28%,70%以上的CO来源于生产时期后溜破碎煤体氧化。根据低变质煤CO来源,采取了有针对性的架后喷洒CO复合抑制剂、采空区压注冷氮及漏风封堵等综合防控措施,使回风隅角及回风流CO体积分数大幅降低。

In order to explore the source of low metamorphic coal CO source and reduce the risk of natural fire in the coal seam,Taking the 3#coal seam of Dananhu No.1 mine as the research object,the CO generation rule in the CO occurrence,mining and cutting of the 3#coal seam and the CO source ratio in the corner of the return air are studied by means of temperature programming experiment,experiment simulation and field observation.The results show that when coal is pulverized without oxygen,a large number of functional groups and free radicals generated by the covalent bond fracture of coal molecules interact to produce a very small amount of CO.When coal is pulverized under oxygen,a large amount of CO is produced.With the increase of specific surface area of coal samples,the volume fraction of CO increases and eventually becomes stable.The coal cutting machine produces high temperature,which oxidizes the coal body and produces CO volume fraction of 30−50 ppm.The CO from the goaf accounts for 28%of the total integral number of the CO from the return air corner,and more than 70%of the CO comes from the oxidation of the crushed coal after the production period.According to the CO source of low metamorphic coal,comprehensive prevention and control measures such as spraying CO compound inhibitor after the frame,pressure injection of cold nitrogen in goaf and air leakage plugging have been taken to reduce CO volume fraction in return air corner and return air flow significantly.