提出了一种基于统计量的差分吸收光谱SO2浓度反算方法, 利用差分吸收度标准差的大小表征SO2浓度的高低。 使用主元素分析(principle component analysis, PCA）方法对差分吸收光谱进行处理, 将处理结果、 信号相关度与标准差结合为综合统计量, 用于反算SO2的浓度。 该方法应用于光程为0.3 m的烟气浓度在线监测系统, 其SO2浓度测量的量程为0～5 800 mg·m-3。 对系统进行了非线性标定, 反算浓度的满量程误差不超过0.7%FS, 在没有气体的情况下测量数值为-4.54 mg·m-3。

A concentration retrieving method using statistics is presented, which is applied in differential optical absorption spectroscopy (DOAS) for measuring the concentration of SO2. The method uses the standard deviation of the differential absorption to represents the gas concentration. Principle component analysis (PCA) method is used to process the differential absorption spectrum. In the method, the basis data for the concentration retrieval of SO2 is the combination of the PCA processing result, the correlation coefficient, and the standard deviation of the differential absorption. The method is applied to a continuous emission monitoring system (CEMS) with optical path length of 0.3 m. Its measuring range for SO2 concentration is 0～5 800 mg·m-3. The nonlinear calibration and the temperature compensation for the system were executed. The full scale error of the retrieving concentration is less than 0.7%FS. And the measuring result is -4.54 mg·m-3 when the concentration of SO2 is zero.