Metallurgical Coke Combustion with Different Reactivity under Nonisothermal Conditions: A Kinetic Study

The combustion characteristics and kinetics of high- and low-reactivity metallurgical cokes in an air atmosphere were studied by thermogravimetric instrument. The Coats-Redfern, FWO, and Vyazovkin integral methods were used to analyze the kinetics of the cokes, and the kinetic parameters of high- and low-reactivity metallurgical cokes were compared. The results show that the heating rate affected the comprehensive combustion index and combustion reaction temperature range of the cokes. The ignition temperature, burnout temperature, combustion characteristics, and maximum weight-loss rate of low-reactivity coke (L-Coke) were better than high-reactivity coke (H-Coke). Low-reactivity coke had better thermal stability and combustion characteristics. At the same time, it was calculated via three kinetic analysis methods that the combustion activation energy gradually decreased with the progress of the reaction. The coke combustion activation energy calculated by the Coats-Redfern method was larger than the coke combustion activation energy calculated by the FWO and Vyazovkin methods, but the laws were consistent. The activation energy of L-Coke was about 4~8 kJ/mol more than that of H-Coke.