不同煤阶热解半焦的FT-Raman光谱研究

不同煤阶热解半焦的FT-Raman光谱研究

  • 摘要: 在热天平上采用慢速升温制备了褐煤、高挥发分烟煤和低挥发分烟煤的半焦。采用FT-Raman光谱对半焦进行了分析。半焦800 cm-1至1 800 cm-1的Raman光谱可分解为10个谱带,以表征高度无序炭材料中的典型结构。光谱和谱带的强度比都可用来描述半焦的结构特征。在600 ℃低温热解时,三种煤半焦的结构差异明显。随热解温度升至800 ℃或900 ℃,这种差别消失。褐煤中可交换的钠离子影响热解过程中的成焦反应。

     

    Abstract: A brown coal, a high-volatile bituminous coal and a low-volatile bituminous coal were pyrolysed at a slow heating rate in a thermogravimetric analyser. The char samples were characterised with FT-Raman spectroscopy using a 1 064 nm laser. The Raman spectra of these chars between 800 cm-1 and 1 800 cm-1 were then deconvoluted with 10 Gaussian bands representing the typical structures found in highly disordered carbon materials. Both total Raman intensity (peak area) and the Raman band intensity ratios from spectral deconvolution are useful parameters for the description of the structural features of coal chars. While the chars from the brown coal, the high-volatile bituminous coal and the low-volatile bituminous coal differ significantly at low pyrolysis temperatures (e.g. 600 ℃), the differences diminish with increasing pyrolysis temperature to 800 ℃ or 900 ℃. The ion-exchangeable Na in brown coal affects the char-forming reactions taking place during pyrolysis.

     

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