Study on the Effect and Mechanism of Water Immersion on the Characteristic Temperature during Coal Low-Temperature Oxidation
Study on the Effect and Mechanism of Water Immersion on the Characteristic Temperature during Coal Low-Temperature Oxidation
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DOI：
10.1007/s11053-021-09854-0
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发表时间：
2021-03
影响因子：
5.4
通讯作者：
X. Zhai;Bobo Song;Bo Wang;Teng Ma;Hui Ge
中科院分区：
文献类型：
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作者：
X. Zhai;Bobo Song;Bo Wang;Teng Ma;Hui Ge
针对水浸干煤自燃对煤炭资源的巨大浪费，研究了水浸对煤低温氧化特征温度的影响及其可能的原因。用热重法测定了煤的氧化特征温度。通过液氮吸附/脱附实验和原位傅里叶变换红外光谱，从孔结构和微观官能团的角度分析了特征温度变化的可能原因。结果表明，在煤低温氧化初期，DWIC样品的特征温度低于原煤样品。DWIC与原煤的特征温度之差随着温度的升高先增大后减小。当煤的温度上升到最大增重温度时，差异几乎消失。水浸降低了煤的比表面积，但增加了煤的平均孔径和总孔容。煤孔隙的这些变化有利于氧的运移和运移。在整个低温氧化阶段，DWIC羟基浓度高于原煤，这使得煤与氧发生初始反应的可能性较大。在低温氧化后期，甲基浓度对煤-氧反应有较大影响。
Spontaneous combustion of dried water-immersed coal (DWIC) wastes many coal resources, and so the effect of water immersion on the characteristic temperature during coal low-temperature oxidation and its possible reasons were investigated. The characteristic temperatures of coal oxidation were obtained by thermogravimetry. The possible causes for the changes in characteristic temperatures were analyzed from the pore structure and microscopic function groups by means of liquid nitrogen adsorption/desorption experiment and in-situ Fourier transform infrared spectroscopy. The results show that, in the early stages of coal low-temperature oxidation, the characteristic temperatures of DWIC samples were lower compared to those of raw coal samples. The differences between the characteristic temperatures of the DWIC and raw coal first increased but then decreased as the temperature rose. When the coal’s temperature rose to the maximum weight gain temperature, the differences had almost disappeared. Water-immersion reduced the coal’s specific surface area but increased the average diameter of its pores and the total pore volume. These changes in the coal pores were beneficial for oxygen migration and transport. During the whole low-temperature oxidation stage, the DWIC hydroxyl concentration is higher compared to that of raw coal, and this made the initial reaction of coal and oxygen more likely to occur. In the late low-temperature oxidation stages, the methyl concentration had a considerable influence on the coal–oxygen reaction.