par Cafiero, Marianna 
;Sharma, Saurabh ;Kamal, Muhammad Mustafa ;Lubrano Lavadera, Marco;Iavarone, Salvatore ;Coussement, Axel ;Parente, Alessandro
Référence Proceedings of the Combustion Institute, 40, 1-4, 105336
Publication Publié, 2024-01-01
;Sharma, Saurabh ;Kamal, Muhammad Mustafa ;Lubrano Lavadera, Marco;Iavarone, Salvatore ;Coussement, Axel ;Parente, Alessandro Référence Proceedings of the Combustion Institute, 40, 1-4, 105336
Publication Publié, 2024-01-01
Article révisé par les pairs
| Résumé : | This experimental work provides insights into the effects of oxygen (O2) enrichment on pure ammonia (NH3) combustion in a 20-kW semi-industrial scale furnace featuring an industrial-grade burner operated under MILD/Flameless conditions. The impact of O2 enrichment on the NH3 combustion stabilization, the flame and furnace temperature, the exhaust emissions, and the OH* chemiluminescence were explored. The tests were conducted by varying O2 concentration in the oxidizer stream from 21 % to 50 % and using two different oxidizer injectors to achieve average inlet velocities of 80 m/s and 150 m/s while keeping the inlet power and the total oxidizer mass flow rate constant. Stable flameless combustion with a distributed reaction zone and a consistent and uniform temperature profile throughout the combustion chamber was achieved with O2 enrichments higher than 34 %. Nevertheless, high levels of NH3 slips were observed, which were drastically reduced to negligible concentrations at higher O2 enrichments. On the contrary, NO emissions increased with the O2 fraction with an opposite non-linear trend compared to that of NH3 slip. An optimum trade-off between NOx emissions and NH3 slip was achieved by co-firing NH3 with O2=37 % with ID16 and 36 % with ID20 injector. This study also compares the behavior of pure O2-enriched NH3 combustion under flame and MILD combustion conditions to highlight the advantages of oxygen-enhanced NH3 flameless combustion. While operating in flame mode ensured a stable ammonia oxidation process already at low O2 enrichment=30 %, NO emissions and NH3 slips were significantly higher than those measured under MILD conditions. Finally, the impact of varying industrial load and the related heat balance on the NH3 slip was assessed at different levels of O2 enrichments at a fixed equivalence ratio. The overall results show that O2-enriched flameless ammonia combustion can simultaneously expand the range of stable combustion and reduce NO and NH3 emissions. |
