An investigation into a carbon burnout kinetic model for oxy–coal combustion

This paper investigates coal char burnout kinetics in the oxygen-enriched environments of oxy–coal combustion. The Carbon Burnout Kinetic model (CBK) developed by Hurt et al. was used as the basic model for air–coal combustion and a modified version for oxy–coal combustion. In order to assess the performance of the original CBK model published experimental data from standard char combustion studies at near-atmosphere and elevated pressures were used. The results of the evaluation suggested that the modified model can be utilized for oxy–coal applications. The modifications include the integration of Langmuir–Hinshelwood kinetic rate mechanisms for C–CO2 and C–H2O reactions and the effects of CO and H2 concentration on these reactions. The modified code is validated using published experimental data. It is shown that using this modified code, the burnout prediction in both N2 and CO2 environments has improved significantly. Computed results of Loss on Ignition (LOI) in a 1 MWth pilot scale combustion test facility are compared with experimental data.