不同煤阶热解半焦的FT-Raman光谱研究

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.