Advancing carbon-neutral iron production: Non-equimolar diffusion kinetics of coke with H2O in hydrogen-rich blast furnaces

This study presents a non-equimolar diffusion model to enhance the predictive accuracy of coke degradation kinetics in hydrogen-rich blast furnaces, where elevated water vapor (H₂O) levels are present. The model integrates the unreacted core shrink model with the Maxwell-Stefan equation to delineate the 3D curved surface distribution of H₂O concentration and the effective diffusion coefficient within the coke ash layer. Validated against experimental data, the model demonstrated a significant improvement in accuracy, with a deviation range of 0.77%-3.5%, compared to the 15.61%-18.92% deviation for the traditional unreacted core shrink model. This advancement is crucial for optimizing blast furnace design and operation, supporting the industry's transition toward low-carbon ironmaking. The findings highlight the importance of considering non-equimolar diffusion in the reaction kinetics between coke and H₂O, contributing substantially to the scientific understanding and technological advancement in ironmaking.