基于自由基反应的易自燃煤低温氧化过程分析

Analysis on Low Temperature Oxidation Process of Spontaneous Combustion Coal Based on Free Radical Reaction

为了从微观层面上探寻易自燃煤体低温氧化过程中活性基团的反应机理,基于煤的低温氧化模拟实验平台,采用ESR技术,分析煤体低温氧化过程中自由基反应特性。实验表明:随着煤体氧化温度的升高,自由基种类先增加后减少,自由基浓度持续升高了48.3%,氧化温度升高至100℃时,自由基种类最多,自由基浓度由缓慢增加了10.2%开始转变为急剧增加了31.7%。自由基浓度和种类在100℃有1个拐点,100℃是煤体低温氧化的容许最高温度,在深部易自燃煤层抽采和采空区遗煤自燃治理过程中,煤体局部或整体温度达到100℃后,必须采取有效措施及时抑制煤体升温,这对于深部易自燃煤层开采与采空区遗煤自燃治理过程中自燃预测预报和防灭火非常重要。

In order to explore the reaction mechanism of active groups in the low temperature oxidation process of spontaneous combustion coal from micro level, based on low temperature oxidation simulation experiment platform and electron spin resonance（ESR） technology, this paper analyzed the reaction characteristics of free radicals in low-temperature oxidation of coal.Experiments showed that with the increase of coal oxidation temperature, free radical types increased then decreased and concentration continually increased by 48.3%. When the oxidation temperature reached to 100 ℃, there were the most types of free radicals and their concentration increased from a slow increase of 10.2% to a sharp increase of 31.7%. Free radical concentration and types have an inflection point in the 100 ℃, so 100 ℃ is the allowable maximum temperature of low temperature oxidation of coal. When the partial or overall temperature of coal reached to 100 ℃, the effective measures must be taken to prevent the coal from heating up in time. It is very important to predict spontaneous combustion and prevent the fire extinguishing in the process of mining deep coal seam and residual coal spontaneous combustion control in the gob.