A comparative study of effects of methane and hydrogen on ammonia combustion in air via reactive molecular dynamics.

Ammonia (NH 3) is a promising substitute for fossil fuels to achieve the net-zero emission targets. To improve the combustion performance of NH 3 , reactive fuels are added to the NH 3 combustion. In the present study, the combustions of NH 3 , CH 4 /NH 3 , and H 2 /NH 3 in air conditions were simulated using a reactive molecular dynamics method. Results suggest that whether the addition of CH 4 and H 2 could accelerate the consumption of NH 3 and reduce NO X emissions depends on the fuel ratio of the reactive gas (CH 4 /H 2) and NH 3 molecules. The acceleration of NH 3 consumption is significant at low H 2 /NH 3 fuel ratios and high CH 4 /NH 3 fuel ratios, as the addition of H 2 and CH 4 lowers the activation energy for NH 3 combustion. NO X emissions are mitigated at low H 2 /NH 3 and CH 4 /NH 3 fuel ratios but increase at high fuel ratios. The pathways for NOx generation and de-NOx reactions were identified. This study unveiled the mechanism via which the reactive fuels affect the NH 3 combustion performance from an atomic perspective. The findings will be useful for the design of high-efficiency and low-emission combustion chambers in ammonia-powered energy systems. • A comparative study of effects of H 2 and CH 4 on NH 3 combustion was elucidated. • Pathways of NO X formation and de-NO X reactions were extracted. • A comprehensive understanding was provided between additives and fuels in NH 3 combustion. [ABSTRACT FROM AUTHOR]