Impact of biomass addition on organic structure and mineral matter of char during coal-biomass co-gasification under CO2 atmosphere

To study the transformation of organic structure and mineral matter in coal-biomass mixtures during co-gasification, the anthracite and rice straw addition with different ratios were isothermally gasified at 1100 °C under CO2 atmosphere in a fixed bed reactor. The phase-mineral composition, morphology and organic structure of solid residues produced at different gasification time were analyzed by X-ray diffraction, scanning electron microscopy coupled with energy dispersive spectrometer, Raman spectroscopy and other methods. Results revealed that the organic structure was changed in char as it became less ordered with the addition of biomass. The bulk concentrations of K and Na and their bearing minerals and phases in char increased with the addition of biomass during gasification process. The transformation of mineral matter played a significant role in promoting the coal gasification.