Study On Spontaneous Combustion Characteristics Of Coal-Oxygen Composite Intrinsic Reaction

Coal spontaneous combustion fire is one of the five disasters in mine,which seriously restricts the safe and efficient mining of coal in China.The low temperature oxidation process of coal mainly includes coal-oxygen composite reaction,water volatilization and coal self-pyrolysis.At present,when studying the low temperature oxidation process of coal,the above reaction path is mainly analyzed as a whole,so the coal oxygen reaction characteristics obtained are more susceptible to other reactions.Therefore,to carry out the most essential research on the characteristics of coal and oxygen composite intrinsic reaction,to further clarify the theory of coal and oxygen composite action,coal natural combustion mechanism to provide theoretical guidance.Based on this,two coal samples,Shendong long-flame coal（SD）and Donghuantuo gas coal（DHT）,were selected to obtain the spontaneous combustion characteristics of coal-oxygen composite intrinsic reaction after eliminating the interference of water volatilization,gas desorption and coal self-pyrolysis by the method of the difference reduction of each characteristic parameter in air atmosphere and nitrogen atmosphere.The gas production rule of coal-oxygen complex intrinsic reaction was obtained by using the difference subtractive method by using temperature-programmed gas chromatography.The actual gas release amount of each index under this path is more than 90%of the total release amount in low temperature oxidation stage.Using thermogravimetric analysis,it was found that the weight loss of the two coal samples was 4%and the weight gain was3.1%under the combined intrinsic reaction path of coal and oxygen in low temperature oxidation stage,respectively.The total mass of the two coal samples increased by 5.8%and 2.2%,respectively,compared with that under air atmosphere,which corrected the decrease of coal mass caused by pyrolysis and other paths.Fourier in situ infrared technology was used to monitor the content changes of active groups in coal samples.It was found that with the decrease of-CH₃ and-CH₂-content,the gas release increased gradually.The coal-oxygen complex intrinsic reaction begins to take place at 60～70℃,enters the critical acceleration stage at 110℃,and enters the intense oxidation stage at about 160℃.Figure 31;Table 8;Reference 53...