Thermal degradation, characterization and kinetic modeling of different particle size coal through TGA

Abstract

The thermal degradation and kinetics of coal is a key element for the design of pyrolysis process. In order to optimize the particle size effect on coal conversion and reaction kinetics, this research work elucidates the thermal degradation and reaction kinetics of Indian coal with different particle size (106–150, 212–300, 300–425, 425–600 and 600–1000 µm). The pyrolysis behaviours of different particle size coal were investigated through thermo-gravimetric analysis (TGA) under various heating rates with the temperature range 30 °C to 950 °C. The kinetic parameters were calculated using an iso-conversional model free Ozawa-Flynn-Wall (OFW) analysis. All the experimental results obtained from TGA, were validated with model prediction for all four heating rates. Good agreement with model prediction was found for all experimental TGA data. The results showed that the particle size of the coal sample remarkably affects the mass loss with the change in heating rate. These findings can provide the crucial data for the different industrial applications such as designing, handling and modelling of different coal gasifiers as well as other pyrolysis and gasification process. Our results also reveal that the Ozawa-Flynn-Wall approach used for coal kinetics helps significantly to calculate the meaningful activation energy.