基于光谱吸收的CO2气体检测系统

针对CO₂气体实时在线监测的应用需求,以比尔-朗伯定律为理论基础,基于可调谐半导体激光吸收光谱技术搭建一套CO₂气体在线检测系统。选择吸收谱线波长为1 609.583 nm,并在系统中搭建两路参考光路用于消除光源信号波动和实现自动寻峰,以提高检测系统的稳定性与准确性。通过对系统的标定与校准,系统测量相对误差小于0.8%,系统重复性小于0.06%,响应时间不超过18 s,对空气中CO₂的体积分数进行连续4 h监测,其值的波动范围为360×10^-6 ~ 400×10^-6。试验结果表明该系统具有较好的稳定性与可靠性,可满足CO₂气体实时在线监测的应用需求。

Study on CO2 detecting system based on spectrum absorption

To meet the application requirements of real-time carbon dioxide (CO₂)-gas online monitoring, this paper proposes an online detection system for the CO₂ gas based on tunable diode laser absorption spectroscopy according to the theory of Beer-Lambert law. The selected absorption spectrum wavelength of the system is 1 609.583 nm. Futher, two reference optical paths are built to eliminate the signal fluctuation of the light source and automatically detect the absorption peak to improve the stability and accuracy of the detection system. The calibration of the system shows that the relative measurement error of the system is less than 0.8%, the system repeatability is less than 0.06%, and the response time is less than or equal to 18 s. Continuous monitoring of CO₂ in the air for 4 h shows that the fluctuation range of the volume fraction measurement is 360×10^-6 to 400×10^-6. The system has good stability and reliability and can meet the application requirements of real-time CO₂ gas online monitoring.