TDLAS直接吸收法测量CO_2的基线选择方法

Selection of baseline method in TDLAS direct absorption CO_2 measurement

本文基于可调谐半导体激光吸收谱线(TDLAS)技术的直接吸收测量,选用中心工作波长为1 580 nm的DFB激光器,在室温及大气常压条件下检测了模拟烟气中的CO_2浓度;采用去峰拟合法和纯N2线拟合法获得基线后反算出了CO_2的浓度,并将反算结果进行了对比。结果表明:采用纯N2线拟合法反算出的浓度的最大相对误差为2.64%,均方值为1.69%;采用去拟合法反算出的浓度的最大相对误差为9.81%,均方值为7.81%。以纯N2吸收谱线作基线的纯N2线拟合方法反算出的浓度的准确度较高,可以为CO_2浓度测量的基线选择提供参考。

Based on the direct absorption measurement of absorption spectrum of tunable diode laser absorption spectroscopy（ TDLAS） technology,the DFB laser of 1 580 nm center wavelength is chosen to detect the concentration of CO2 in simulated flue gas at room temperature and atmospheric pressure. The concentration of CO2 is computed by removing absorption peak fitting method and pure N2 line fitting method,and the two computed results are compared. The results show that the maximum relative error of concentration is 2.64% for the pure N2 line fitting method,and the mean square value is 1.69%; the maximum relative error of concentrationgot from the removing absorption peak fitting method is 9.81%,and the mean-square value is 7.81%. Using the method of pure N2 line fitting method,the accuracy of concentration is greatly improved,so the method can provide baseline selection reference for CO2 measurement.