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.