Enhancing NO_x emission control and energy efficiency of H₂/NH₃ powered micro generator in a planar porous combustor

Micro-thermoelectric system fueled by hydrocarbon with the simple construction, no moving parts and high energy density, have garnered extensive attention. However, micro combustors are facing challenges of low energy efficiency and high emissions due to the significant surface-volume ratio and elevated heat loss ratio.

Improving the energy efficiency and decreasing NO_x emissions of H₂/NH₃ fueled combustion for micro power generation.

Experimental tests and numerical analysis are conducted to examine the coupling effects of NH₃ blending and porous media (PM) on flame behavior and chemical reactions, affecting the optimizing energy efficiency and emissions reduction.

The findings reveal that increasing NH₃ blending ratios affects flame regime and reduces heat loss via inlet section. Optimal NH₃ blending ratio of 20 % exhibit peak NO emissions due to sufficient OH, N, and HNO concentrations, while the NO emission is reduced by 49.4 % for the augment of NH₃ to 30 %. The introduction of PM effectively mitigates flame blowout and strengthens radiation heat transfer by modifying flow field, flame regime, radical distribution, and enhance heat transmission. Moreover, the concentration of NO in the PM region decreases sharply, resulting in a 5.5 % reduction in NO emissions compared to the combustor without PM. Analysis of reaction pathways suggests promoting the conversion of NH_i in the N₂ direction as a promising strategy for reducing NO emissions.

It provides valuable insights into optimizing NH₃ blending ratios and utilizing PM for improving combustion efficiency and reducing NO_x emissions in H₂/NH₃ combustion systems.