长焰煤低温氧化主要官能团迁移规律研究

Study on transfer law of main functional groups in low temperature oxidation of long flame coal

煤自燃是引起煤矿火灾的主要原因,宏观上表现为煤自燃释放热量不断积聚,最终导致煤体升温引发火灾;微观上表现为煤中的活性官能团不断与氧进行各种氧化反应产生热量,不同煤种微观结构的种类和数量不同导致煤自燃倾向性不同。为研究典型杨伙盘长焰煤的原始波谱图、特征温度点的红外结构参数变化规律和主要官能团的迁移规律,采用原位漫反射傅里叶变换红外光谱测试系统,测量煤氧化过程中官能团的变化,得到了长焰煤原始煤样的波谱图;采用Origin软件对原始波谱进行分峰拟合,得出了各官能团的含量;计算分析了不同特征温度点下的红外结构参数,并与阳泉无烟煤进行了对比分析。结果表明:原始煤样中长焰煤的内表面积比较大,内部结构疏松,脂肪氢含量较多,脂肪链长度较短,芳香缩合度较低,更易发生自燃;随温度升高,各个温度点结构参数I_1长焰煤小于无烟煤,结构参数I_2长焰煤大于无烟煤,结构参数I_3长焰煤为先递减后递增的趋势;长焰煤中羟基、脂肪烃和含氧官能团是较活跃的基团,主要受自身羟基含量、烷基侧链和脂肪烃长链的影响,在煤氧化过程中变化较大,对煤的氧化反应影响较大;芳香烃在长焰煤中的变化较小,相对比较稳定。

Spontaneous combustion of coal is the main cause of fire in coal mine.The macroscopic performance is the continuous accumulation of the coal spontaneous combustion release heat,and finally leads to a fire caused by the temperature rise of the coal body.The microstructure shows that the active functional group in the coal is continuously reacted with oxygen to generate heat,and the types and quantity of the micro-structures of different kinds of coal can lead to different spontaneous combustion tendency of the coal.In order to study the original spectrum of typical Yanghuopan long flame coal,the variation of infrared structure parameters of characteristic temperature points and the migration law of main functional groups,the change of functional groups in the process of coal oxidation was measured by in situ diffusion reflection Fourier transform infrared spectroscopy system,and the wave spectrum of the original coal of long flame coal was obtained.The original spectrum was fitted by Origin,and the content of each functional group was obtained.The infrared structure parameters at different characteristic temperature points were calculated and analyzed,and the comparison analysis was carried out with Yangquan anthracite.The results showed that the internal surface area of long flame coal in the original coal was large,the internal structure was loose,the hydrogen content of fat was more,the length of fat chain was short,the degree of aromatic condensation was low,and spontaneous combustion was more likely to occur.With the increase of temperature,the structural parameter I1of long flame coal was smaller than anthracite,the structure parameter I2of long flame coal was larger than anthracite,and the structure parameter I3of long flame coal decreased at first and then increased.The hydroxyl,aliphatic hydrocarbons and oxygen-containing functional groups in long flame coal were active groups,which were mainly affected by their own hydroxyl content,alkyl side chain and long chain of fatty hydrocarbons.They changed greatly in the process of coal oxidation and had great influence on the oxidation of coal.The change of aromatic hydrocarbons in long flame coal was small and relatively stable.