Characterization of the structural features of char from the pyrolysis of cane trash using Fourier transform-Raman spectroscopy

Structural features of chars from the pyrolysis of cane trash in a fluidized-bed/fixed-bed reactor under both slow and fast heating rate conditions were investigated using Raman spectroscopy. Chars from the pyrolysis of coals were also investigated for comparison. Spectra were curve-fitted using 10 Gaussian bands representing different structural features of the chars. Differences in the total Raman intensity between cane trash chars and the chars of 3 coals of varying rank were great at low pyrolysis temperature (600 °C) but decreased as the pyrolysis temperature was increased to 900 °C. Both low (10 K min^-1) and high (> 10³-10⁴ K s^-1) particle heating rates resulted in increased aromatization and relative aromatic ring size with increasing pyrolysis temperature from 600 to 900 °C. However, pyrolysis at slow and fast heating rates gave chars of very different structural features as revealed by Raman spectroscopy.