浸水对煤氧化活化能和热效应的影响

为了研究浸水对煤自燃的影响,选取不同变质程度的煤样,制备相同含水率的原煤和浸水煤样进行红外光谱和热重实验。对比分析红外光谱,发现浸水煤的活性基团增多,氧化活性高于原煤。应用TG曲线,基于判定煤自燃难易的着火活化能理论,研究了原煤和浸水煤在氧化自燃过程中的活化能变化,结果表明浸水煤的失水活化能增加到原煤的1. 01～1. 29倍,说明在受热条件下浸水煤中的水分更难蒸发出来;浸水煤的着火活化降低为原煤的0. 51～0. 89,说明浸水煤干燥后更容易发生自燃;浸水前后煤的燃烧活化能基本不变,说明浸水过程不影响煤的燃烧阶段。通过DSC曲线,分析了原煤和浸水煤在氧化自燃过程中的热效应变化,发现浸水煤的氧化放热量升高至原煤的1. 04～1. 59倍,从热量变化的角度说明浸水煤更容易自燃。

Effect of soaking on coal oxidation activation energy and thermal effect

In order to study the effect of soaking on coal spontaneous combustion,the coal samples with different ranks were selected,and the FT IR and thermos gravimetric experiments were carried out on the same moisture content of raw coal and soaked coal.Compared the Infrared Spectra,it is found that the active groups in the soaked coal increase and the oxidation activity is higher than that of raw coal.Based on the TG curves and the theory of ignition activation energy of coal spontaneous combustion,the activation energy of raw coal and soaked coal in the process of oxidization and spontaneous combustion was also studied.The results show that the water loss activation energy of soaked coal increases to 1.01-1.29 times of that of raw coal,which indicates that water is harder to evaporate in soaked coal under the condition of heating.The ignition activation energy of soaked coal reduces to 0.51-0.89 of raw coal,which indicates that the soaked coal is more prone to spontaneous combustion.The combustion activation energy of coal before and after soaking is basically the same,which indicates that soaking process does not affect the burning stage of coal.The thermal effect of raw coal and soaked coal in the process of oxidizing and spontaneous combustion was analyzed based on the DSC curves.It is found that the amount of heat released from soaked coal is increased to 1.04-1.59 times of raw coal,which indicates that the soaked coal is more spontaneous from the point of heat.