An experimental and kinetic modeling study of NH3 oxidation in a Jet Stirred Reactor

The increasing interest towards renewable, and more sustainable energy sources imposes a widerange analysis of the underlying chemistry, in order to maximize the efficiency of combustion devices and reduce pollutant emissions. In this context, ammonia chemistry has recently gained major attention: it is present in biogas and bio-oil, in trace amounts. Investigating ammonia chemistry can benefit from several studies carried out in the past decades on its pyrolysis and oxidation behavior. However, scarce literature is available on the conditions of interest previously mentioned, since the presence of ammonia in trace amounts results in superoxidative conditions. The available kinetic models of ammonia have been built up by mostly relying on hightemperature data, obtained in ideal reactors. On the other side, few work has been carried out to investigate its oxidation at lower temperatures. In order to further investigate this topic, and to provide a stronger support for kinetic model validation, in this study the oxidation of ammonia in diluted conditions, at relatively low temperatures (T < 1200 K) and a pressure close to atmospheric, is investigated by using a Jet Stirred Reactor. In addition to ammonia conversion, the formation of Nitrogen Oxides (NOx) is also analyzed. At the same time, a detailed kinetic mechanism for ammonia oxidation is developed by leveraging the most recently available kinetic data on experimental and theoretical reaction rates, and is used to analyze the obtained data, after being validated against the literature data in similar conditions