可调谐半导体激光光谱仪对高温CO的测量研究

Carbon Monoxide Measurement at Elevated Temperature Based on Tunable Diode Laser Absorption Spectroscopy

搭建了一套基于可调谐半导体激光光谱技术的测量装置,实现了对高温环境中CO的检测。此装置采用波长调制技术,并选取CO在6395.4 cm!1的R14线作为吸收线,不仅提高了装置的信噪比,降低了检出限,还可以避开其它气体组分的干扰。通过建立不同温度下的水汽背景库来扣除CO吸收峰处的水汽干扰信号,同时得到水汽浓度和温度的信息,再结合温度信息以及建立的CO标准库,实现对CO的测量。测量结果表明,对CO浓度的检测范围在0.1%~10%之间,检出限为0.03%,测量误差在5%以内;温度的检测范围为300℃~1000℃,测量误差在10%以内。此装置能为炼钢冶炼及发电燃烧过程提供CO浓度及温度信息,从而提高燃烧效率,降低尾气排放。

A measurement device based on tunable diode laser absorption spectroscopy was developed to measure CO concentration at elevated temperature condition. Based on wavelength modulation, R14 transition,around 6395. 4 cm!1,was selected as the absorption line to enhance the signal to noise ratio and detection limit,and avoid the interferences of other combustion gases. By building up a water absorption background database at different temperatures,the interference by water transition around CO absorption line can be eliminated,and the water concentration and temperature information can be obtained simultaneously.After measuring the temperature,CO concentration was detected by combining with the CO standard absorption database. The experimental results showed the CO detection range and limit of detection for the device was0. 1%-10% and 0. 03% respectively with an error below 5%,and the measured temperature was as high as1000℃ with an error below 10%. This device could provide CO concentration and temperature information in real-time for steel plant and power plant to increase combustion efficiency and decrease exhaust emission.