基于SO_(2)吸收谱线的光谱仪波长在线校准方法  

Online calibration of the wavelength of spectrometer based on SO_(2)absorption spectrum

作　　者：苗丰 许传龙[1] 李健[1] 张彪[1] 韩少鹏 汤光华 MIAO Feng;XU Chuanlong;LI Jian;ZHANG Biao;HAN Shaopeng;TANG Guanghua(School of Energy and Environment,Southeast University,Nanjing 210096,Jiangsu,China;Nanjing Guodian Environmental Protection Technology Co.,Ltd.,Nanjing 210096,Jiangsu,China)

机构地区：[1]东南大学能源与环境学院,江苏南京210096 [2]南京国电环保科技有限公司,江苏南京210061

出　　处：《化工进展》2024年第2期818-822,共5页Chemical Industry and Engineering Progress

基　　金：国家自然科学基金(52376158)。

摘　　要：紫外差分吸收光谱技术已被广泛用于工业污染源废气排放浓度监测。光谱仪作为紫外烟气分析仪的核心器件,易受到温度变化而产生波长漂移,进而影响监测结果的准确性。本文提出了一种光谱仪波长“软”标定方法,通过实验建立标准SO_(2)吸收谱线极值波长数据库,利用SO_(2)吸光度极值像素点和标准SO_(2)吸收光谱极值波长,对光谱仪像素点与波长的对应函数进行重新拟合,以实现光谱仪波长实时校准。搭建了实验系统,并开展了光谱仪波长标定方法验证研究。结果表明,当光谱仪所处环境温度变化范围为10℃时,采用本文方法可以使993mg/m^(3)NO标气的测量误差从115.2mg/m^(3)降低至21.4mg/m^(3),绝对误差减小了93.8mg/m^(3);当被测SO_(2)为1430mg/m^(3)时,测量系统信噪比较高,波长校准效果最佳;针对低浓度测量现场,可通过增加光谱平均次数来增强光谱信号的信噪比,提高波长在线校准方法的效果。Ultraviolet differential absorption spectroscopy technology has been widely used in the monitoring of industrial flue gas emissions.The spectrometer,a core component of the UV flue gas analyzer,is susceptible to wavelength drift caused by temperature changes,which in turn affects the accuracy of pollutants monitoring results.In this paper,a soft wavelength calibration method for spectrometers is proposed.A standard SO_(2)absorption spectrum peak wavelength database is established through experiments.When the wavelength drift exceeds 0.02nm,the corresponding function between the spectrometer pixel and wavelength will be re-fitted using the pixel of the SO_(2)absorption peak in conjunction with the database.This method enables real-time calibration of the spectrometer wavelength.Experiments are conducted to validate the proposed calibration method.Results showed that with a 10℃environmental temperature range,this method can reduce the measurement error of 993mg/m^(3)NO standard gas from 115.2mg/m^(3)to 21.4mg/m^(3),with an absolute error reduction of 93.8mg/m^(3).The best wavelength calibration effect is achieved when the measured SO_(2)concentration is 1430mg/m^(3).For low-concentration measurement sites,the signal-to-noise ratio of the spectral signal can be amplified by increasing the number of spectral averages,thereby improving the effectiveness of the online wavelength calibration method.

关 键 词：紫外差分吸收光谱 光谱仪 波长校准 吸收光谱 

分 类 号：TQ533.6[化学工程—煤化学工程] TG115.339[金属学及工艺—物理冶金]