Thermal Characteristics and Kinetic Insights into CO₂ Regasification of Candle Coal Pyrolysis Residues from Coalfield Fires

To investigate the regasification thermal characteristics of candle coal pyrolysis residues, thermogravimetric (TG) experiments were conducted using residues subjected to different constant temperatures. Two stages of thermal decomposition were observed in the 300-500 °C range, leading to varying pyrolysis residual structures with a critical transition point of around 400 °C. Fourier transform infrared spectroscopy results indicate that the cleavage of numerous weak chemical bonds during pyrolysis promotes increased aromatization of coal. CO₂ regasification of the pyrolysis residue was influenced by the pyrolysis process, with higher constant pyrolysis temperatures resulting in increased gasification concentration but decreased gasification intensity. Gasification kinetic analysis revealed the decrease in the apparent activation energy with increasing constant pyrolysis temperature, suggesting reduced energy requirements for CO₂ regasification under these conditions.