低温热转化过程中煤中典型壳质组的荧光和Micro-FTIR特征

Fluorescence and Micro-FTIR characteristics of typical liptinite at low temperature thermal conversion

  • 摘要: 煤中壳质组的种类及含量对热解焦油、煤气产率有重要的影响。综合利用显微镜热台、荧光显微分析和显微傅里叶红外光谱(Micro-FTIR)研究煤中典型壳质组的低温热转化( ≤ 450 ℃)特性。结果表明,随着温度升高,煤中壳质组分的相对荧光强度降低,最大荧光波长增大;树脂体和木栓质体的荧光特性在240 ℃开始变化,280−320 ℃变化显著;孢粉体、角质体和沥青质体A的荧光特性在280 ℃开始变化,320−360 ℃变化显著;藻类体的荧光特性从280 ℃开始变化,并持续到400 ℃;沥青质体B的荧光变化出现在320−360 ℃。藻类体的脂肪化合物的吸收峰最强,其次为沥青质体、树脂体、角质体和孢粉体;随着温度升高,壳质组的脂肪族和含氧基团逐渐减少,芳香烃含量相对增加。煤中壳质组分芳构化程度低,在低温热转化过程中基本保持不变;壳质组的富氢程度及脂肪化合物变化特征与荧光特性的变化基本一致。

     

    Abstract: The subgroups and contents of liptinite have significant influence on yields of tar and gas in pyrolysis.The heating stage microscope, fluorescence analysis and Micro-FTIR were used to study the characteristics of typical liptinite at low temperature thermal conversion. The results showed that the relative fluorescent intensities decreased and the maximum fluorescence wavelength increased as the pyrolysis temperature increase. The fluorescence characteristics of resinite and suberinite began to change at 240 ℃, and remarkable changed at 280−320 ℃. The fluorescence characteristics of sporinite, cutinite, and bituminite A began to change at 280 ℃, and remarkable changed at 320−360 ℃. The fluorescence characteristic of alginite began to change at 280 ℃, and lasting changed till 400 ℃. The fluorescence characteristic of bituminite B changed at 320−360 ℃. The absorption peak of aliphatic compound in alginite was strongest, and the peaks of bituminite, resinite, cutinite, and sporinite decreased in turn. The aliphatic compounds and oxygen-containing groups of liptinite group decreased and the content of aromatic hydrocarbon relatively increased as the temperature increase. The aromatization degree of liptinite group was low and basically remain unchanged at low temperature thermal conversion. The hydrogen-rich degrees and the change of aliphatic chains of liptinite group confirmed well with the fluorescence characteristics.

     

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