Chemical Industry and Engineering Progress ›› 2024, Vol. 43 ›› Issue (2): 818-822.DOI: 10.16085/j.issn.1000-6613.2023-1439

• Column: multiphase flow test • Previous Articles     Next Articles

Online calibration of the wavelength of spectrometer based on SO2 absorption spectrum

MIAO Feng1,2(), XU Chuanlong1(), LI Jian1, ZHANG Biao1, HAN Shaopeng2, TANG Guanghua2   

  1. 1.School of Energy and Environment, Southeast University, Nanjing 210096, Jiangsu, China
    2.Nanjing Guodian Environmental Protection Technology Co. , Ltd. , Nanjing 210096, Jiangsu, China
  • Received:2023-08-17 Revised:2023-12-17 Online:2024-03-07 Published:2024-02-25
  • Contact: XU Chuanlong

基于SO2吸收谱线的光谱仪波长在线校准方法

苗丰1,2(), 许传龙1(), 李健1, 张彪1, 韩少鹏2, 汤光华2   

  1. 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
  • 通讯作者: 许传龙
  • 作者简介:苗丰(1986—),男,博士研究生,研究方向为烟气监测技术。E-mail:13852287920@163.com
  • 基金资助:
    国家自然科学基金(52376158)

Abstract:

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 SO2 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 SO2 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/m3 NO standard gas from 115.2mg/m3 to 21.4mg/m3, with an absolute error reduction of 93.8mg/m3. The best wavelength calibration effect is achieved when the measured SO2 concentration is 1430mg/m3. 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.

Key words: ultraviolet differential absorption spectroscopy, spectrometer, wavelength calibration, absorption spectrum

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SO2吸收谱线极值波长数据库,利用SO2吸光度极值像素点和标准SO2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/m3 NO标气的测量误差从115.2mg/m3降低至21.4mg/m3,绝对误差减小了93.8mg/m3;当被测SO2为1430mg/m3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。

关键词: 紫外差分吸收光谱, 光谱仪, 波长校准, 吸收光谱

CLC Number: 

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