Numerical study of low-emission combustion of NH3-H2-N2 mixtures from partial ammonia decomposition

Abstract

Ammonia (NH₃) and hydrogen (H₂) are promising non-carbon fuels for the decarbonization of thermal processes through combustion·NH₃ can serve as an efficient carrier for H₂ through partial decomposition. However, the combustion process of this partially decomposed NH3, especially its NOx emission, requires further investigation. This study employs Computational Fluid Dynamics (CFD) using ANSYS Fluent to simulate premixed combustion of partial NH₃ decomposition through the Reynold Stress Model (RSM) and Eddy-Dissipation Model (EDM). The equivalence ratio varies from 0.2 to 1.4 in increments of 0.1. The RSM and EDM model could estimate the NO_x production effectively without depending on the high computational computer and long-time simulations. Findings indicate that NO_x emissions remain significantly low in rich combustion conditions, starting from an equivalence ratio of 1.1, with values below 150 mg/Nm³.