This study aims to satisfy the growing demand for peak-load regulation in power systems and low-carbon hydrogen production.

A detailed numerical model for the coupled ammonia-hydrogen combustion and decomposition process is established by employing ammonia as an energy storage and hydrogen carrier medium. The model systematically investigates the influences of different burner configurations, such as conventional burners, single-layer porous burners, double-layer porous burners, and staged burners, as well as the inlet ammonia velocity within the decomposition zone on NO_x emission characteristics and ammonia decomposition efficiency. By integrating heterogeneous catalytic kinetics of the Ni-Pt/Al₂O₃ catalyst with porous-medium resistance and heat-transfer models, the simulation framework captures the complex thermo-chemical interactions within the integrated reactor. The reliability of the numerical model is validated through comparison with experimental data reported in the literature, showing an average absolute error of less than 4.4%, which confirms its capability to accurately predict the coupled combustion-decomposition behavior.

The simulation results reveal that the endothermic ammonia decomposition process significantly alters the thermal field within the reactor. The strong heat absorption associated with catalytic decomposition reduces the peak temperature in the combustion zone, thereby effectively suppressing the formation of thermal NO. Although the concentration of N₂O exhibits a slight increase (approximately 7×10^–5%), the overall NO_x emissions are substantially reduced due to the dominant decrease in NO formation. All four burner configurations can achieve an ammonia decomposition rate up to 99.99%. However, notable differences exist in the spatial distribution of regions with high decomposition rates and in the associated emission characteristics. Specifically, the staged burner demonstrates strong capability in NO_x mitigation because of the distributed combustion strategy. Nevertheless, the secondary injection of relatively cold ammonia leads to a delayed initiation of the decomposition reaction, which may influence the system stability under certain operating conditions. The double-layer porous burner exhibits superior thermal storage capacity, enabling sustained catalytic activity. However, localized high-temperature zones within the porous matrix tend to promote the formation of NO. In contrast, the single-layer porous burner provides a more balanced thermal environment, achieving an optimal compromise between NO_x suppression and efficient heat supply for ammonia decomposition, thus demonstrating the most favorable integrated performance. Further parametric analysis indicates that increasing the inlet ammonia velocity in the decomposition zone enhances convective heat transfer and strengthens the heat-absorption effect of the decomposition reaction. As a result, the combustion temperature is further reduced, leading to a more pronounced decrease in NO formation compared with the slight increase in N₂O. Consequently, the overall NO_x emissions continue to decline with the increasing inlet ammonia velocity. Notably, even at a relatively high inlet ammonia velocity of 10 m/s, the ammonia decomposition rate remains above 90%, indicating robust catalytic performance under intensified flow conditions.

This work elucidates the thermal-chemical synergy mechanism underlying ammonia-hydrogen combustion-decomposition integration. It identifies the single-layer porous burner as the most suitable configuration for power-generation-side peak-load regulation scenarios. The findings provide a solid theoretical foundation and valuable engineering guidance for the integrated design of ammonia energy storage, hydrogen production, and ultra-low-NO_x combustion systems.