On the oxygen-enriched combustion of a single coal char particle

摘要

The paper presents numerical results of single coal char particle combustion in the oxygen-enriched environment at which the effect of the equimolar and non-equimolar counterdiffusion has been taken into consideration. Usually, the phenomenon of the non-equimolar counterdiffusion arising at combustion of char particles is neglected and superseded by the equimolar counterdiffusion. Such a replacement can lead to results, e.g. profiles of particle temperature and species concentrations, which do not agree with the real process. First, the phenomenon of the equimolar and non-equimolar counterdiffusion for a single spherical particle is explained in detail. Next, the governing equations of single char particle combustion are presented. Finally, numerical simulations have been performed at O_2 mole fractions of 26%, 36% and 46% for the particle size of d_p = 160 μm and gas temperature of 1373 K. Numerical results, e.g. profiles of char burnout, temperature, molar fractions at the particle surface, show the significant influence of the non-equimolar counterdiffusion on the combustion.