Ammonia as a Hydrogen Vector: Validated Large Eddy Simulation of Ammonia Co-Firing in a Pilot-Scale Coal Combustor

It is anticipated that ammonia (NH3) will be used as a carbon-free substitute for coal. Even so, regulating NH3-coal co-firing while preserving both nitrogen oxides (NOx) emission and flame stability is an important concern that necessitates the use of a dependable technique to aid in the combustion tuning of the said co-firing. Computational fluid dynamics (CFD) has the capacity to be a promising method for assisting in the said co-firing tuning for NOx reduction in the power plant. Hence, the validated numerical model of NH3 co-firing with sub-bituminous coal was established in the current study through a detailed Large Eddy Simulation (LES) using a pilot-scale coal combustor as the main geometry basis. The predictive performance of the CFD model was assessed by comparing it to actual experimental data from the said coal combustor facility, which revealed a less than 10% difference in predicted NOx and temperature profiles for both pure coal firing and NH3 co-firing. Therefore, the validation can be considered satisfactory, and the model can predict NOx emission and combustion behaviour with acceptable accuracy for both coal and NH3 co-firing. Overall, the validated CFD model can be used to gain in-depth insights into NH3 co-firing to aid in combustion tuning for future co-firing implementation at actual utility plants.