可调谐半导体激光吸收光谱法对高温甲烷的测量研究

可调谐半导体激光吸收光谱(TDLAS)是一种具有高灵敏度、高分辨率、快速检测特点的气体检测技术,已广泛用于大气中多种痕量气体的检测以及地面的痕量气体和气体泄漏的检测。研究了利用TDLAS技术测量高温下甲烷浓度的实验方法,使用可加热的静态吸收池对在1653.72nm波长附近R(3)支转动跃迁的吸收线进行了测量,并计算了吸收线强。分别在相同温度不同浓度和相同浓度不同温度的两种条件下进行了实验。结果表明,利用直接吸收的方法,在实验室可以得到370K时的最小可探测限为100×10-6,500K时的最小可探测限为245×10-6(吸收池长度为10cm),可以应用在燃烧控制及喷焰气体浓度测量等多个领域。

Tunable diode laser absorption spectroscopy study of measuring methane at elevated temperatures

Tunable diode laser absorption spectroscopy(TDLAS)is a detective technology with the characteristic of high sensitivity,high resolution and rapid response,which has been used abroad for detection of trace gas in atmosphere and ground,and for measurement of gas leakage.A diode-laser system based on this techniques is developed to monitor CH 4 non-intrusively at elevated temperatures,line strengths of the transition in the R(3)band including three extraordinary near lines near 1653.72nm has been measured in a heated static absorption cell.The experiment had been performed at identical temperature but different concentration and different temperature but identical concentration.The experiment result is proved that used direct absorption method,the minimum detection limit of CH 4 in air is 100×10-6 at 370K,245×10-6 at 500K with 10 cm path length.This method can be applied in many fields including combustion control and concentration measurement of flame.