KINETIC INSIGHTS AND MORPHOLOGICAL TRANSFORMATIONS IN COAL GASIFICATION: AN IN-DEPTH ANALYSIS WITH MODEL VALIDATION

Understanding the reactivity and kinetics of feedstock particles is critical for process optimization, reactor design, and industrial gasifier scaling. This study investigates the impact of particle size on the gasification behavior of coal, focusing on the temperature and gas species concentration profiles during the process. Coal particles of varying sizes (1 mm, 4 mm, 6 mm, and 8 mm) were subjected to high-temperature gasification in a furnace maintained at 1073 K and under limited air supply. Temperature profiles are analyzed. The results indicate that smaller particles (4 mm) achieved higher peak temperatures suggesting faster reaction rates, while larger particles (6mm and 8mm) exhibited slower and lower peak temperatures. We also employed a sophisticated mathematical model integrating key equations for energy balance, heat flux, and char mass balance to simulate the residence time, core temperature and gas concentrations of O2, CO, and CO2 of the coal. Experimental data and model estimates indicate that thermal conductivity increases with particle size, while activation energy decreases at lower temperatures, suggesting higher reaction rates for smaller particles. Based on the validated numerical model, the sharper and faster reactions observed in the gas species concentration profiles for smaller particles indicate quicker gasification. The results show good alignment between experimental data and model predictions. These findings underscore the critical influence of particle size on thermal dynamics and reaction kinetics during coal gasification, highlighting the need for optimized particle size distribution to maximize gasification efficiency.