Chemical kinetic study of ammonia with propane on combustion control and NO formation

In order to investigate the chemical kinetic insight of ammonia combustion and NOx formation by ac-tive promoters, experiment has been conducted in a jet-stirred reactor. This work focuses on ammonia blended with propane oxidation kinetic. Mole fractions of intermediates were detected and measured at the temperature range of 800-1250 K, the equivalence ratio of 0.5-2.0 and the propane volume ratio of 0.2-0.8. NUIG model was chosen as base model of ammonia/propane. Zhang et al. was selected as ammo-nia sub-mech through validated against the large set of experimental data related to the combustion of ammonia. Then it was modified based on sensitivity analysis using high-level quantum calculation results, referred as M-NUIG model. M-NUIG model can accurately predict experimental data under various con-ditions. Pathway analysis was conducted on ammonia combustion under the condition where ammonia is rapidly consumed. HCO, CH3 and IC3H7 are produced through propane oxidation, which further trig-ger the OH and HO2 formation. This pathway boosts the consumption of ammonia. Mole fraction of NO does not change monotonically with temperature, which increases first and then decreases, and increases finally. The deep kinetic mechanism of NO formation and reduction in ammonia oxidation were investi-gated. At the temperature range of 900 to 10 0 0 K, NO formation reactions are less favorable while NO reduction reactions are more dominant. Therefore, NO concentration increases first, and then decreases. With the further increase of temperature, larger formation of active radicals H, O, OH, NH2, NH and HNO radicals leads to the rising of NO formation.(c) 2023 The Combustion Institute. Published by Elsevier Inc. All rights reserved.