LAUSR

Abstract DOAS technology is used in flue gas continuous monitoring systems widely. The method is based on the design of the spectrometer and it is costly. In the paper, a low-cost and high-precision flue mixed gas detection device was proposed. On the basis of DOAS, 255 nm, 275 nm, and 385 nm were selected as the LED wavelength of the measurement channel by observing the ultraviolet spectral absorption structure. The measuring principle was analyzed by synthesizing the effects of Rayleigh scattering and Mie scattering. Aiming at the mixed gases of SO2 and NO2, the three-channel equations were established. And the three-channel photo-detection device was designed to measure their concentrations. The correctness of the method and the accuracy of the measuring device were verified by using SO2 standard gas at a concentration of 301 mg/m3. The measurement result shows that the error of the gas concentration is the minimum at room temperature of 28 °C. The relative error of the measurement is ±1.5%.