Study On Differential Optical Absorption Spectroscopy For Monitering Sulfer Dioxide And Nitric Oxide

In recent years, the flue gas emissions from coal-fired power plant attracted widespread attention. It’s the main cause of PM2.5and acid rain. As a result, continuous emission monitoring system became a focus. This paper studies the gas analysis unit of continuous emission monitoring system, including sulfur dioxide, nitric oxide and oxygen analysis. Ultraviolet differential optical absorption Spectroscopy is used to measure sulfur dioxide and nitric oxide simultaneously. Electrochemical sensor is used to detect oxygen. A UV DOAS based system is built. The entire procedure is studied in detail, including the spectral pretreatment, the spectra feature extraction and the concentration inversion. Furthermore, this paper studies the saturated absorption and nonlinear phenomena of target gases, and the influence from spectrometer temperature fluctuation. The spectral wavelength drift and distortion are corrected. Finally, this paper presents the results of experimental measurements, including the calibration curve and the inversion accuracy of the flue gas concentration, and the system stability.Based on above all, the flue gas pretreatment system is designed and developed. Then, the continuous emission monitoring system prototype in line with national standards is developed, which has a good industrial prospects.