[Objective] This study aims to satisfy the growing demand for peak-load regulation in power systems and low-carbon hydrogen production. [Methods] 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 NOx emission characteristics and ammonia decomposition efficiency. By integrating heterogeneous catalytic kinetics of the Ni-Pt/Al_2O3 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. [Results] 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 N_2O exhibits a slight increase(approximately 7×10–5%)

the overall NOx 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 NOx 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 NOx 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 heatabsorption 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 N_2O. Consequently

the overall NOx 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. [Conclusion] 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-NOx combustion systems.