| In this paper,the coals of Pansan Mine,Gubei Mine and Zhangji Mine in Huainan Mining Area were selected.The effect of oxygen concentration on the spontaneous combustion characteristics of Huainan Coal was studied by experimental analysis.The oxygen concentration was set at 3%,7%,12%,15 and 21%,the main research content is as follows:(1)Using thermogravimetry equipment,the coal samples from three mines in the Huainan Mining Area were tested under different oxygen concentrations,and the TG curves were analyzed in stages according to the experimental results to determine the oxidation of coal samples under different oxygen concentrations.The characteristic temperature,the analysis of the oxygen concentration of its characteristic temperature and thermal weight curve.The results show that the higher the oxygen concentration,the faster the oxidation reaction rate of coal,but the effect of oxygen concentration on the characteristic temperature is not obvious,indicating that the oxygen concentration has a certain impact on the characteristic temperature point,but the effect is not significant.(2)By analyzing the thermal effect of Huainan coal oxidation under different oxygen concentrations,it is concluded that the Pansan coal with heat absorption under different oxygen concentrations is in the range of 238?2364mJ,the Gubei coal is between 485?1350mJ,and Between 18?2279mJ,the heat release range was 29357?59711mJ,34298?68539mJ,and 25075?64681 mJ,respectively.It can be seen that during the oxidation process of coal samples,the heat release is much greater than the heat absorption.It can be seen that the coal-oxygen composite reaction is an exothermic reaction.The oxidation heat release of coal samples from Huainan No.3 Mine is generally consistent with the variation of oxygen concentration.The increase in oxygen concentration increases the heat release gradually.This is because the higher the oxygen concentration,the higher the oxygen consumption rate of coal samples.The more severe the oxidation reaction of coal,the higher the heat release intensity and the greater the heat release.(3)Through the temperature increase experiment of Huainan coal under different oxygen concentration conditions,the gas concentration,oxygen consumption rate,gas production rate,and heat release intensity were analyzed based on the experimental results.The results show that the CO concentration of coal samples in Huainan No.3 Mine is different from that of oxygen.The curve of temperature change with the concentration is similar,and the overall trend is rising with the increase of temperature.At the same temperature,the concentration of CO showed an increasing trend with increasing oxygen concentration.The order of CO concentration from small to large was 3%,7%,12%,15%,and 21%,respectively.Experiments have shown that high oxygen concentration contributes to the development of oxidation,and vice versa,inhibits the development of oxidation.After coal temperature exceeds 60?-80?,the rate of oxygen consumption,CO,CH4,etc.in Huainan coal sample increases sharply.Therefore,it can be concluded that the critical temperature of Huainan coal is around 60? to 80?.Moreover,the CO concentration shows a significant change trend at each temperature stage and different oxygen concentration conditions,and is suitable as a marker gas for detecting spontaneous combustion.At a certain temperature,the oxygen consumption rate of coal samples increases with the increase of oxygen concentration,and the higher the temperature,the greater the variation.(4)Analysis of the oxidation kinetic parameters of Huainan coal under different oxygen concentrations shows that in the first stage of the oxidation reaction,Zhangji coal,Pansan coal,and Gubei coal have oxygen concentrations of 15%,21%,and 21 respectively.The coal oxidation reaction is the easiest to start at the percent;in the second stage of the oxidation reaction,the activation energy of coal samples in the third coal mine of Huainan shows an increasing trend with the increase of the oxygen concentration.In the third stage of the oxidation reaction,the reaction was severe.As the oxygen concentration increased,the activation energy of the coal sample in the Huainan mining area showed a downward trend as a whole.Under the 21%oxygen concentration,the activation energy reached a minimum. |
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