Kinetic and Experimental Analysis of the Effect of Heating Rate on Combustion Performance of Cokes

Under the continuous advancement of the dual-carbon strategy, enhancing the efficient utilization of coke as the primary fuel in sintering processes holds significant importance. This study employed multiscale techniques (XRD, Raman, TG-DTG, DSC, and kinetics) to investigate four types of coke (JY, JH, MJ, WG), establishing a structure-activity relationship between microstructure, heating rate, and combustion behavior for sintering optimization. With high graphitization and ordered structure, JH coke shows rising activation energy under increasing heating rates, which is ideal for stable low-temperature combustion and SO2 reduction. In contrast, WG coke exhibits a defective structure and declining activation energy, enabling rapid high-temperature combustion (>800 °C) with minimal CO emissions via staged combustion. JY coke displays erratic activation energy due to high ash and structural disorder, necessitating pre-screening and blending for controllability. MJ coke achieves stable activation energy through compositional homogeneity and moderate structure, balancing dynamic temperature gradients but requiring ash distribution control to limit liquid phase formation. Heating rate critically modulates combustion: elevating from 5 to 15 °C/min broadens combustion intervals, shifts exothermic peaks from narrow-sharp to broad-high profiles, and enhances reactivity. WG excels at high rates with peak combustion rates and optimal performance. These findings reveal structure-dependent activation energy trends: ordered structures (e.g., JH) resist thermal activation at higher rates, while defective configurations (e.g., WG) promote reactivity. Strategically, JH and WG suit complementary thermal zones. This work provides a structure-activity framework for coke selection and technical pathways to achieve energy-efficient, low-emission sintering, advancing the industry’s low-carbon transition.