弱粘煤低温氧化活性基团与热效应的研究*

为研究煤氧化过程中活性基团的演变规律及热效应的变化特征，利用原位红外实验装置，实时测量煤升温过程中官能团的动态变化，数据处理得到弱粘煤红外波谱图，利用差减法对特征温度点下的红外光谱图进行处理，得到煤样的差示光谱，计算特征温度点下的红外结构参数；采用差示扫描量热仪，测量煤氧化过程中热流的变化，得到弱粘煤的热流曲线图，并对热流曲线进行阶段划分和氧化动力学计算。结果表明:弱粘煤中芳环数量比较少，环周围侧链较长，内部结构疏松，内部毛细管比较发达，内表面积较大，更容易发生自燃；整个氧化过程中羟基最为活跃，含氧官能团次之，其次是脂肪烃；红外参数计算结果HAL，I2整体呈减小趋势，I1，I3整体呈增大趋势；弱粘煤放热阶段的活化能值为25.12～61.26 kJ/mol，并随着升温速率的增大而减小，与此阶段放热量随升温速率的增大而增大相对应。

Study on low-temperature oxygen active groups and thermal effect of weakly caking coal

In order to study the evolution laws of active groups and the change characteristics of thermal effect during the coal oxidation,the dynamic change of functional groups in the process of coal heating was measured by using the in-situ infrared experimental device,and the infrared spectrum diagram of weakly caking coal was obtained though the data processing.Moreover,the differential spectra of coal samples was obtained through processing the infrared spectrum diagram at the characteristic temperature point by using the subtraction method,and the infrared structure parameters at the characteristic temperature points were calculated.The differential scanning calorimeter was used to measure the change of heat flow during the coal oxidation process,then the heat flow curves of weakly caking coal was obtained,and the stage division and oxidation kinetics calculation were conducted on the heat flow curves.The results showed that the number of aromatic rings in weakly caking coal was relatively smaller,and the side chain around the ring was longer.Meanwhile,the internal structure was loose,the internal capillary was relatively developed,the internal surface area was larger,and the spontaneous combustion was more likely to happen.The hydroxyl group was the most active during the entire oxidation process,followed by oxygen-containing functional groups and aliphatic hydrocarbons.The infrared parameter calculation results HAL，I2 presented an overall decreasing trend,and I1 ，I3 overall presented an increasing trend.The activation energy of weakly cohesive coal in the exothermic stage was 25.12~61.26 kJ/mol,and decreased with the increase of heating rate,corresponding to the increase of heat release at this stage with the increase of heating rate.