Comparative analysis of thermokinetic behavior and gaseous products between first and second coal spontaneous combustion
Comparative analysis of thermokinetic behavior and gaseous products between first and second coal spontaneous combustion
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DOI：
10.1016/j.fuel.2018.04.070
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发表时间：
2018-09-01
期刊：
影响因子：
7.4
通讯作者：
Shu, Chi-Min
中科院分区：
文献类型：
--
作者：
Xiao, Yang;Ren, Shuai-Jing;Shu, Chi-Min
为了研究一次和二次煤自燃的全过程，采用了15 t煤自燃实验炉和同步热分析仪，并结合傅里叶变换红外光谱进行了研究。实验测试过程如下：首先，在不干预的情况下，将煤温从31.0℃（室温）提高到452.7℃。其次，煤样品在厌氧气氛中被冷却到大约90.0摄氏度。第三步，给样品供气，直到样品温度达到418.0℃。最后，在厌氧气氛中再次将煤冷却到100.0℃。研究了温度、质量、热能强度和气体产物的变化规律。结果表明：在一次和二次煤自燃过程中，温度变化率先增大后减小；与第一次自燃相比，在升温速率为2.5℃/min时，第二次自燃燃烧阶段的温度和质量损失率变化较大，而在其他升温速率（5.0、10.0和15.0℃/min）下，放热反应速率和质量损失率变化较小。在300.0℃之前，第一次和第二次煤自燃时CO、CO2、烷烃和烯烃的差异不显著，但第二次煤自燃时CO和CO2的排放量明显高于第一次煤自燃时，而高于300.0℃时，烷烃和烯烃的释放量明显减弱。第一次煤自燃时H2O含量高于第二次煤自燃时。
To investigate the entire process of first and second coal spontaneous combustion, a 15-t experimental furnace for coal spontaneous combustion and synchronous thermal analyzer coupled with Fourier transform infrared spectroscopy were employed. The process of experimental tests was as follows: First, coal temperature was increased from 31.0 degrees C (room temperature) to 452.7 degrees C without intervention. Second, the coal sample was cooled to approximately 90.0 degrees C in an anaerobic atmosphere. Third, air was supplied until the sample reached 418.0 degrees C. Finally, the coal was cooled again to 100.0 degrees C in an anaerobic atmosphere. The variations of temperature, mass, heat energy intensity, and gaseous products were investigated. The results indicated that the temperature change rate first increased and then decreased during the first and second coal spontaneous combustion. Compared with the first coal spontaneous combustion, the rates of temperature and mass loss change with a heating rate of 2.5 degrees C/min were higher at the combustion stage of the second coal spontaneous combustion, but the variations of the exothermic reaction rate and mass loss with other heating rates (5.0, 10.0, and 15.0 degrees C/min) were lower. The differences among CO, CO2, alkanes, and alkenes during the first and second coal spontaneous combustions were insignificant until 300.0 degrees C. However, the emission of CO and CO2 during the second coal spontaneous combustion was significantly higher than during the first coal spontaneous combustion, whereas the release of alkanes and alkenes was substantially weaker when the temperature was higher than 300.0 degrees C. Moreover, the amount of H2O during the first coal spontaneous combustion was higher than that during the second coal spontaneous combustion.