煤自然发火气体指标及其有机官能团响应特征研究

Study on the response characteristics between gas indicators of spontaneouscombustion and organic functional groups of coal

为了探究煤自然发火气体产物与有机官能团的内在关联,通过程序升温实验和原位红外光谱实验,分析了低温氧化阶段煤自燃气体产物释放规律,阐述了煤自燃过程的微观结构变化特征,预测了高温阶段气体产物变化。结果表明,煤自燃的临界温度及干裂温度分别为50℃和90℃,释放的碳氧气体及烃类气体随温度升高呈现抛物式增长。临界温度后,各类官能团呈现不同的变化规律,其中,含氧官能团、羟基和脂肪烃变化最明显。通过灰色关联度方法,计算出不同官能团和气体产物的关联度,发现羰基(C=O)是影响碳氧气体和烃类气体最主要的官能团。最后结合官能团在高温阶段的含量变化,推测出煤样在高温阶段释放的气体浓度呈现先增多后减少的趋势。

In order to explore the intrinsic relationship between spontaneous combustion gas products and organic functional groups of coal,the release law of gas products from coal spontaneous combustion during low-temperature oxidation stage was analyzed through temperature programmed experiments and in-situ infrared spectroscopy experiments,the microscopic changes in the process of coal spontaneous combustion were explained,and the changes in gas products during high-temperature stage were predicted.The results showed that the critical temperature and dry cracking temperature of coal spontaneous combustion were 50℃and 90℃,respectively,and the released carbon oxygen gas and hydrocarbon gas exhibited parabolic growth with increasing temperature.After the critical temperature,various functional groups exhibited different patterns of change,among which oxygen-containing functional groups,hydroxyl groups,and fatty hydrocarbons showed the most significant changes.The correlation between different functional groups and gas products was calculated by the grey correlation method,and it was found that carbonyl(C=O)was the most important functional group affecting carbon oxygen gas and hydrocarbon gas.Based on the changes in the content of functional groups during the high-temperature stage,it was inferred that the gas concentration released by the coal sample during the high-temperature stage showed a trend of first increasing and then decreasing.