Research on the method and device for detecting the concentration of methane and ethane dual gas based on TDLAS

Natural gas and biogas, as commonly used combustible gases, are widely used in urban residents and industrial enterprises. Gas leakage accidents occur frequently. In order to more accurately distinguish whether it is a natural gas leak or a biogas leak, this paper proposes a method for simultaneous detection of methane and ethane based on TDLAS, and develops a set of methane and ethane dual gas detection devices. Firstly, this paper studied the gas absorption lines of methane and ethane. According to the absorption lines, a 1680nm DFB laser beam was used to scan methane and ethane at the same time. Secondly, the phase-locked amplifier module of TDLAS technology is used to obtain the second harmonic signals of methane and ethane concentration detection at the same time, and identify the components of methane and ethane based on the peak position information and FWHM information of the second harmonic signal. Finally, the concentration calculation function is obtained by fitting the peak and valley difference of the second harmonic. Experimental results show that the detection method and device proposed in this paper can achieve simultaneous detection of methane and ethane