短光程下差分吸收光谱法测量烟气浓度的研究

Study on measurement of flue gas concentration based on DOAS in short light path

介绍了一种基于差分吸收光谱技术(DOAS)的烟气浓度反演方法,将该方法应用于实际的多组分气体检测中。文中使用短光程和分辨率较低的国产光谱仪,在信噪比较低的情况下,应用DOAS算法,设计了基于最小二乘法的NO和SO2混合气体浓度计算方法;详细介绍了NO和SO2气体的差分吸收截面获取方法,详述了SO2和NO混合气体在不同波段的浓度反演方法;在常温常压下,实现了单组分SO2、NO气体和混合气体的在线实时监测。实验结果表明,方法能够检测短光程下(300mm)的单组分SO2、NO气体和混合气体,检测结果比较稳定,误差较小。

A method is introduced for inversion of flue gas concentration based on Differential Optical Absorption Spectroscopy(DOAS),and applies the method to practical multi-component gas detection.With a short light path and low-resolution domestic spectrometer,in the case of relatively low signal-to-noise,the DOAS algorithm is used to design a method for calculating the concentration of Sulfur dioxide and Nitric oxide based on the least square method.The method of obtaining the absorption cross section of Sulfur dioxide and Nitric oxide is introduced,and details the inversion method of the concentration of Sulfur dioxide and Nitric oxide in different wavelength bands.At normal temperature and pressure,real-time online monitoring were performed on single-component SO2,NO gas and mixed gas.The experimental results show that this method can detect single-component Sulfur dioxide,Nitric oxide and mixed gas at a short light path(300 mm).The detection result is stable and the error is small.