基于双球面镜多通池的高灵敏度甲烷检测系统  

High Sensitivity Methane Detection System Based on Double Spherical Mirror Multi-pass Cell

作　　者：彭晶晶 杨坤[2] 李梦 PENG Jingjing;YANG Kun;LI Meng(Anhui Institute of Information Technology,Wuhu 241100,China;School of Mechatronics Engineering,Anhui University of Science and Technology,Huainan 232001,China)

机构地区：[1]安徽信息工程学院机械工程学院,安徽芜湖241100 [2]安徽理工大学机电工程学院,安徽淮南232001

出　　处：《红外技术》2024年第12期1425-1432,共8页Infrared Technology

基　　金：基于柔性电子测量与信息挖掘技术的颈肩疲劳辅助诊断与理疗系统研究(2023AH040383);安徽理工大学研究生创新基金资助项目(2023cx2062)。

摘　　要：为了准确测量环境大气中的痕量气体甲烷浓度,采用可调谐二极管激光吸收光谱(TDLAS)技术,选取中心波长为1653 nm的分布反馈式(DFB)激光器作为激光光源,搭建甲烷检测系统。针对系统中的探测器噪声与光学干涉条纹噪声,利用加入射频噪声源、多次平均以及卡尔曼(Kalman)滤波方法,来提高系统检测精度。实验结果表明:结合长光程多通池和TDLAS技术对甲烷浓度进行检测,标定的甲烷浓度与系统检测的二次谐波信号峰值有良好的线性关系;当积分时间为213 s时,Kalman滤波后系统的最低检测限为0.14 ppb;确定加入射频噪声源的最优参数,比较多次平均以及利用Kalman滤波进行数据处理,在平均时间为10 s时测量精度为144 ppb,而经过Kalman滤波后测量精度达到134 ppb,表明Kalman滤波可以实现较高的测量精度。To accurately measure the concentration of trace gas methane(CH4)in ambient atmosphere,tunable diode laser absorption spectroscopy(TDLAS)technology was adopted,and a distributed feedback(DFB)laser with a central wavelength of 1653 nm was selected as the laser light source to build a CH4 detection system.For the detector noise and optical interference fringe noise in the system,radio frequency(RF)noise source,multiple averaging,and Kalman filtering were added to improve the detection accuracy of the system.The experimental results show that the calibrated CH4 concentration has an ideal linear relationship with the peak value of the second harmonic signal detected by the system by combining the long optical path multi-pass cell(MPC)and TDLAS technology.The minimum detection limit of the Kalman filtered system is 0.14 ppb when the integration time is 213 s.By determining the optimal parameters for adding RF noise sources and comparing multiple averaging techniques,a measurement accuracy of 144 ppb at an averaging time of 10 s was achieved.After applying Kalman filtering for data processing,the measurement accuracy reached 134 ppb,indicating that Kalman filtering can achieve high measurement accuracy.

关 键 词：TDLAS技术 多通池 甲烷检测 KALMAN滤波 最低检测限 

分 类 号：TH741[机械工程—光学工程]