一种提高SO2和NOx分析仪稳定性与准确度的方法

摘要

针对基于差分吸收光谱(DOAS)技术的烟气分析仪,其核心部件光谱仪受环境温度变化和振动影响.会出现波长漂移.设计一种光谱仪波长快速在线校准方法,利用SO2气体在202～214 nm和280～310 nm波段上的特征吸收峰,根据波峰、波谷与像素点的映射关系,进行三阶拟合,从而实现对光谱仪输出波长进行快速在线校准 研究结果表明,采用波长快速校准后,在202～214 nm和280～310 nm两个吸收波段上波长漂移量降低97.7％,测量误差可控制在2％以内,极大地提高了烟气分析仪的稳定性和测量准确度.%As for the DOAS technology-based flue gas analyzer,wavelength drift may take place due to the impact of ambient temperature and vibration on its core part,i.e.,the spectrometer.An online method to quickly calibrate the wavelength of the spectrometer is designed in this paper.By taking advantage of the characteristic absorption peaks of SO2 standard gas in the wave bands of 202～214 nm and 280～310 nm,the three-order fitting is conducted based on the mapping relation of wave crest,trough and pixel,such that a rapid online calibration can be performed on the output wavelength of the spectrometer.The research results show that the drift can be reduced by 97.7％ in the wave bands of 202～214 nm and 280～310 nm,with the indication error less than 2％,which turns out to be a significant improvement for the stability and measuring accuracy of the gas analyzer.