Nitrogen dioxide (N2O) is a greenhouse gas that is harmful to the ozone layer and contributes to global warming. Many other nitrogen oxide emissions are controlled using the selective non-catalytic reaction (SNCR) process, but N2O reduction methods are few. To avoid future air pollution problems, N2O reduction from industrial sources is essential. In this study, a N2O decomposition and NO formation under an argon atmospheric N2O gas mixture were observed in a lab-scale SNCR system. The reaction rate and mechanism of N2O were calculated using a reaction path analyzer (CHEMKIN-PRO). The residence time of the gas mixture and the temperature in the reactor were set as experimental variables. The results confirmed that most of the N2O was converted to N2 and NO. The change in the N2O reduction rate increased with the residence time at 1013 and 1113 K, but decreased at 1213 K due to the inverse reaction. NO concentration increased with the residence time at 1013 and 1113 K, but decreased at 1213 K owing to the conversion of NO back to N2O.

Nitrous oxide (N 2 O) is one of the greenhouse gases that contribute to global warming. But, there are few methods for controlling N 2 O directly. It is essential to reduce N 2 O to solve environmental problems. In this study, we investigate the O 2 concentration dependence of N 2 O decomposition under an argon-based gas mixture in a high-temperature thermal reactor. The gas concentrations are calculated using CHEMKIN. The results confirm that more N 2 O is converted to N 2 or NO at lower O 2 concentrations. Therefore, the conversion process is hindered by increasing the O 2 concentration. We propose a modified parameter of N 2 O decomposition, and it is employed in the CHEMKIN calculations. With the modified parameter, the experimental results are in a similar tendency to the calculated results.

N 2 O is a hazardous greenhouse gas. It should be reduced to solve global warming problems. In this study, experiments of N 2 O thermal decomposition were conducted by simulating the exhaust gas atmosphere emitted during the combustion of air and pure oxygen in an actual circulating fluidized bed system and incinerator system. As a result of comparing the N 2 O reduction rate in N 2 and CO 2 atmospheres, the N 2 O reduction rate in the CO 2 atmosphere was 20% higher than that in the N 2 atmosphere. It is judged that the N 2 O reduction rate is high in a CO 2 atmosphere (exhaust gas from pure oxygen combustion) due to complex factors such as the reverse reaction, the diffusion coefficient, and static pressure-specific heat. Therefore, pure oxygen combustion increases the reduction rate of nitrous oxide. In addition, when operated with an appropriate residence time and temperature, a reduction effect of more than 95% can be expected, and the fuel consumption rate is also expected to improve.