ABSTRACT
N2O is a hazardous greenhouse gas. It should be reduced to solve global warming problems. In this study, experiments of N2O 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 N2O reduction rate in N2 and CO2 atmospheres, the N2O reduction rate in the CO2 atmosphere was 20% higher than that in the N2 atmosphere. It is judged that the N2O reduction rate is high in a CO2 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.
ABSTRACT
Nitrous oxide (N2O) is one of the greenhouse gases that contribute to global warming. But, there are few methods for controlling N2O directly. It is essential to reduce N2O to solve environmental problems. In this study, we investigate the O2 concentration dependence of N2O 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 N2O is converted to N2 or NO at lower O2 concentrations. Therefore, the conversion process is hindered by increasing the O2 concentration. We propose a modified parameter of N2O 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.
