Anthracite combustion kinetics study by thermal analysis

Abstract：The effect of heating rate on anthracite pyrolysis and combustion process was investigated by thermal analysis curves（TG-DSC）,the isoconversional method and Malek method were applied to determine the most probable mechanism function of each stage,and the anthracite kinetics model was also established.The results indicate that the higher heating rate,the lower weight loss rate at the same temperature,the burnout temperature is also higher.With increasing heating rate,the ignition characteristic changes from hetero-homogeneous ignition to heterogeneous ignition.At the lower heating rates,a part of carbon is oxidated accompanied with pyrolysis before the carbon ignition temperature,the oxidation reaction is the controlling step,and the mechanism obeys the retraction balls model function.When the heating rate increases,before the carbon ignition temperature it follows the SB（m,n） mode function with coal pyrolysis rate controlling.The combustion in carbon surface and a part of internal area follows the cylindrical symmetry three-dimensional diffusion model and the stable phase of combustion followed the RO（n） mode function.