光声光谱多组分气体分析仪的交叉干扰特性研究

设计了一套基于红外热辐射光源的光声光谱多组分气体分析仪。通过分析多组分气体间交叉干扰的主要因素以及特征气体的红外吸收谱线,确定了中红外带通滤光片的参数。利用标准气体对设计的光声光谱仪进行标定,研究了待测气体之间交叉干扰的定量关系,并利用湿度发生器对装置受到水气干扰情况进行分析。实验结果表明,C₂H₂对CH₄、CH₄对C₂H_6的干扰水平分别达到10.49μV/(μL/L)、18.66μV/(μL/L),其他烃类气体间的干扰可以忽略。CO₂对CO、CH₄、C₂H₂和C₂H₄干扰响应度分别为1.615μV/(μL/L)、0.055μV/(μL/L)、0.130μV/(μL/L)以及0.016μV/(μL/L)。此外,水气对C₂H₂、CH₄、C₂H_6、C₂H₄、CO和CO₂都会产生一定的干扰,干扰的响应度分别为0.591μV/(μL/L)、0.421μV/(μL/L)、0.071μV/(μL/L)、0.007μV/(μL/L)、0.051μV/(μL/L)和0.055μV/(μL/L)。实验结果表明C₂H₂对CH₄、CH₄对C₂H_6、CO₂对CO以及高浓度水气对其他气体的检测会产生较高水平的干扰,在测量过程中应当考虑扣除。

Cross Interference Characteristics of Photoacoustic Spectroscopy Multi-gas Analyzer

A photoacoustic spectroscopy multi-gas detection system based on infrared heat radiation light source was developed.The broadband mid-infrared thermals radiation source and band-pass filter were used to generate the photoacoustic excitation light.Combined with a small-volume non-resonant photoacoustic cell,the time-sharing measurement of multi-component gas concentration was realized.The parameters of the mid-infrared bandpass filter were determined by analyzing the main factors of crossinterference among multi-component gases and the infrared absorption spectrum of target gases.To determine the quantitative relationship of cross interference among the gases to be measured,the photoacoustic spectrometer system was calibrated by using the standard gas,and a humidifier was used to analyze the interference from water vapor.The experimental results showed that the interference levels of C₂H₂ to CH4 and CH4 to C2H6 reached 10.49μV/(μL/L)and 18.66μV/(μL/L)respectively,and the interference between other hydrocarbon gases can be ignored.The responsiveness of CO₂ to CO,CH4,C₂H₂ and C₂H₄ interference was 1.615μV/(μL/L),0.055μV/(μL/L),0.130μV/(μL/L)and 0.016μV/(μL/L),respectively.In addition,water vapor will cause certain interference to C₂H₂,CH4,C2H6,C₂H₄,CO and CO₂,and the responsiveness of the interference was 0.591μV/(μL/L),0.421μV/(μL/L),0.071μV/(μL/L),0.007μV/(μL/L),0.051μV/(μL/L)and 0.055μV/(μL/L).The experimental results indicated that there was a high level of interference when detecting CH4 in C₂H₂ background,C2H6 in CH4 background,CO in CO₂ background,and other target gases in high concentration water vapor background,which should be considered in the measurement process.