Numerical study of hydrogen peroxide enhancement of ammonia premixed flames. (15th October 2020)

• Record Type: Journal Article
• Authors: Wu, Fang-Hsien; Chen, Guan-Bang
• Is Part Of: Energy. Volume 209(2020)
• Publication Date: 2020-10-15
• Subjects: NH3 -- Hydrogen peroxide -- Numerical simulation -- Laminar burning velocity -- Flammability limit; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2020.118118
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: NH3 is considered a promising alternative for hydrocarbon-based fuels. However, NH3 /air combustion has many challenges, including a high ignition temperature and low flame speed. Hydrogen peroxide can be used to overcome these defects. The effects of hydrogen peroxide on the NH3 /air premixed flames are numerically investigated using a detailed chemical mechanism. When using hydrogen peroxide to replace partial air, the laminar burning velocity and adiabatic flame temperature are substantially increased. For higher replacement of hydrogen peroxide, the laminar burning velocity is dominated by hydrogen peroxide reactions related to OH. In addition, addition of hydrogen peroxide increases the species concentration and enhances reaction rates. The dominant reactions for species reaction rates are shifted, especially for OH and H2 O. H2 O is mainly formed from the reaction of hydrogen peroxide attacked with radical OH after the amount of added hydrogen peroxide exceeds 40%. As for NO emissions, it also increases due to the presence of NH3 and the higher flame temperature. Since hydrogen peroxide can substantially increase the combustion speed of NH3, thereby extending the flammability limit, it is feasible to control NO emissions by adjusting the replacement percentage of hydrogen peroxide and operating at a lower equivalence ratio. Highlights: The enhancement of H2 O2 on Ammonia/air combustion is numerically studied. The laminar flame speed is substantially increased with air replaced by H2 O2. The reactions of H2 O2 related to OH dominate the laminar flame speed. The reactions of species production rates are altered especially for OH and H2 O. NO emission can be controlled since H2 O2 extends the flammability limit.