Characteristics of continuous analyzers for nitrous oxide in flue gas from municipal incinerators

The accuracy of data obtained with a continuous N2O spectrophotometric analyzer, is compared with data from a laboratory gas chromatograph for emissions of N2O, a global greenhouse gas, from municipal incinerators. Associated CO2 interfered with the determination by the N2O analyzers in the range ±1 ppm. The differences between the measured values by the N2O analyzer and the gas chromatograph depended on the level of interference from CO2. We confirm that the N2O analyzers are useful for the continuous determination of N2O in the flue gas from municipal incinerators if their characteristics are previously understood. The concentration of N2O in the flue gas from the municipal incinerators always varied in the range from a few ppm to ∼ 20 ppm. The concentration of N2O decreased when the concentration of NOx increased and increased when the concentration of NOx decreased. The ratio of N2O/NOx was in the range from ∼ 0.02 to 0.16 and increased with a decrease of NOx. The formation of N2O in the munieipal incinerator was considered to be dependent on the content of nitrogen in the waste and independent of the incineration temperature. Little N2O was formed by the TiO2-V2O5 catalyst used for NOx reduction in the incineration facility although the formation of N2O in the laboratory has been reported.