Study on the response characteristics between gas indicators of spontaneous combustion and organic functional groups of coal
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.