煤分子结构特性是研究煤氧化自燃过程和煤自燃机理的基础,即煤低温氧化过程中煤分子结构变化规律是解释煤自燃原因的根本途径,不同温度的煤表面官能团变化规律研究对探究煤自燃特性具有重要意义。以雁南褐煤、红阳焦煤与南阳坡无烟煤为研究对象,采用程序升温实验方法,测试煤低温氧化过程中气体产物生成规律,采用傅里叶变换红外光谱法(FTIR)分析不同变质程度煤的微观化学结构特征,并探究温度对煤分子表面官能团的影响,从宏观和微观上揭示、表征煤自燃的内在属性。研究表明:在煤低温氧化过程中,气体产物生成量随温度的升高而逐渐增大,煤分子结构断裂,芳香核缩合;随着煤变质程度的加深,气体产物生成量减小,煤分子表面的含氧官能团含量减少,活性降低,煤自燃能力减弱;随着温度的增加,煤分子表面甲基、亚甲基整体呈增加趋势,羟基整体呈现出先减后增再减趋势,羧基、羰基呈现增加趋势。

The characteristic of coal molecular structure is the basis for studying the process of coal oxidation andspontaneous combustion and the mechanism of coal spontaneous combustion, the change law of middling coal molecu⁃lar structure in the process of coal low⁃temperature oxidation is the fundamental way to explain the cause of coal spon⁃taneous combustion, which is of great significance to the study of coal spontaneous combustion characteristics. TakingYannan lignite, Hongyang coking coal and Nanyangpo anthracite as the research objects, the temperature pro⁃grammed system was used to test the law of gas product formation during low temperature oxidation of coal. The micro⁃structure characteristics of coal with different metamorphic degrees were analyzed by Fourier transform infrared spec⁃troscopy (FTIR). The influence of temperature on the surface functional groups of coal molecules was explored. Theintrinsic properties of coal spontaneous combustion were revealed and characterized from macro and microscopic. Theresults shows that: the amount of gas products increased with the increase of temperature, the molecular structureof coal was broken and aromatic nucleus condensation was carried out in the process of coal oxidation at low tempera⁃ture. With the deepening of coal metamorphism, the amount of gas products decreased, the content of oxygen⁃contai⁃ning functional groups on the surface of coal molecules decreased, the activity decreased, and the spontaneous com⁃bustion ability of coal weakened. With the increase of temperature, the methyl and methylene groups on coal molecu⁃lar surface increased as a whole, the hydroxyl groups decreased at first, then increased and then decreased,and the carboxyl and carbonyl groups increased.