Author(s)

Fenglian Fan, Yongcai Guo, Jingfang Zhao, Yanping Wang and Fang Chen

Corresponding Author

Fenglian Fan

ABSTRACT

In order to achieve ultra-low emission online monitoring with higher accuracy, the paper demonstrates a new method of low concentration SO2 measurement based on DOAS and fast Fourier transform. Wavelet domain denoising was applied according to the characteristics of noise of raw spectrum. To reduce spectral leakage, the fast Fourier transform with Hanning window is used to extract the broad-band component of optical density. This method is a new differential absorption spectrum analysis method, which can be well fit the slow varying part of the original spectrum. When concentration ranges from 3 to 31ppm, the relative error of retrieved result is under 2%, and in many cases even lower than 1%. Experiment results indicate that the method in this work has high accuracy and linearity.

KEYWORDS

Coal-fired power plant, Sulfur dioxide, DOAS, Fast Fourier Transform