DOAS烟气测量系统的温度非线性补偿方法

基于紫外差分吸收光谱技术,针对温度对烟气浓度测量的影响,提出一种非线性补偿方法.在紫外波段200-230nm波长范围内,以SO2和NO标准气体为研究对象,从50℃到90℃间隔10℃变化测量其吸收光谱,利用多项式拟合的方法计算气体差分吸收截面,研究温度与吸收截面的定性和定量关系.实验结果显示,不同波长点的两种气体吸收截面随温度变化呈非线性关系.采用非线性补偿修正后,SO2和NO的测量误差明显减小,该方法可提高烟气测量的准确度.

Nonlinear Temperature Calibration Method for the Flu Gas Concentration Determination Using DOAS

A nonlinear calibration model between the differential absorption cross-section of the standard gases and the temperature was established to reduce the temperature influence on the flu gas concentration measurement using differential optical absorption spectroscopy（DOAS）. The absorption spectra of standard gases of SO2 and NO were obtained at 200--230nm from 50℃ to 90℃ with an interval of 10℃. The nonlinear model between the differential absorption cross-section and temperature was then calculated by a polynomial fitting. The experimental results indicate that both absorption cross-sections of the two standard gases nonlinearly vary with temperature and the prediction errors of SOz and NO significantly decrease after calibrated by the nonlinear modeling method,which can improve the accuracy of flue gas concentration monitoring.