Experiments on Combustion Thermodynamics and Kinetics for Different Coal Ranks

To investigate combustion thermodynamics and kinetics for different coal rank, TG-DSC test was conducted on long-flame coal (LFC), gas-fed coal (GFC), and coke coal (CC) under different heating rates. Based on the DSC curve, the combustion process of coal can be divided into five stages: dehydration and desorption stage, chemical adsorption stage, transition stage, combustion stage, and burnout stage. With the increase in heating rate, the combustion characteristic parameters and the exothermic quantity show an upward trend. Under the consistent condition of the heating rate, the coal rank is positively correlated with its characteristic temperature, and negatively correlated with the maximum exothermic quantity. The kinetics experimental results show that the differential method exhibited higher fitting coefficients compared to the integral method, indicating its greater reliability in calculating results. Moreover, the activation energy increased with the increase of the coal rank under the same heating rate. CC has the highest activation energy, followed by GFC and LFC. These findings provide data support for the combustion law of similar coal types.