传统的差分吸收光谱(DOAS)算法对于短光程、低浓度的气体测量存在较大的误差。为了提高测量精度, 将基于差分吸收光谱技术的浓度反演算法应用于烟气SO2的在线监测中。在DOAS算法的基础上, 设计了基于最小二乘法的SO2浓度计算方法, 同时为了节约测量成本, 使用短光程和低精度光谱仪进行测量, 对低浓度SO2气体进行了光谱测量和浓度反演实验。实验结果表明, 在低浓度0~10-6的量程内, 测量值的绝对误差在2/106左右, 相对误差在5%以内, 测量结果较稳定。该算法在短光程下对低浓度的SO2气体具有较高的测量精度, 可以准确、快速地实现SO2气体的在线测量。

Traditional DOAS algorithm has large error when applied to the monitor the low concentration at short light length. To improve the measurement accuracy, the concentration of the inversion algorithm based on the DOAS technique is originally applied to online monitor the sulfur dioxide in flue gas. Based on the DOAS method, an improved algorithm based on least square method is designed, and in order to save the cost of the measurement, short light length and low accuracy spectrometers are applied to the concentration inversion of SO2. Experimental results show that, in the low concentration range 0~10-6, the absolute error is about 2/106, relative error is less than 5%,the measurement results is stable. For short light path length and low concentrations of SO2 gas, the method can accurately and quickly realize online measurement.