Flameless combustion is a well known measure to reduce NO, emissions in gas combustion but has not yet been fully adapted to pulverised coal combustion. Numerical predictions call provide detailed information oil the combustion process thus playing a significant role in Understanding the basic mechanisms for pollutant formation. In simulations of conventional pulverised coal combustion the gasification by CO2 OF H2O is usually omitted since its overall contribution to chat oxidation is negligible compared to the oxidation with O-2. In flameless combustion, however, due to the Strong recirculation of for combustion products, primarily CO2 and H2O, and the thereby reduced Concentration Of O-2 in the reaction zone the local partial pressures Of CO2 and H2O become significantly higher than that for O-2. Therefore, the char reaction with CO2 and H2O is being reconsidered. This paper presents a numerical Study oil the importance of these reactions oil Pollutant formation in flameless Combustion. The numerical models used have been validated against experimental data. By varying the wall temperature and the burner excess air ratio, different cases have been investigated and the impact of considering gasification oil the prediction of NO formation has been assessed. It was found that within the investigated ranges of these parameters the fraction of char being gasified increases LIP to 35%. This leads to changes ill the local gas composition, primarily CO distribution, Which ill turn influences NO formation predictions. Considering gasification the prediction of NO emission is LIP to 40% lower than the predicted emissions Without gasification reactions being taken into account. (C) 2009 The Combustion Institute. Published by Elsevier Inc. All rights reserved.