CH4/C2H6 dual gas sensing system using a single mid-infrared laser

Methane (CH4) and ethane (C2H6) dual gas sensor with low system complexity and strong stability is proposed. The correction method based on absorbance spectrum is applied, and the cross-interference of C2H6 to CH4 is eliminated. In the single gas concentration measurement, linear fitting is performed between the absorbance and concentration of CH4 and C2H6, and the correlation coefficients of R2 = 0.99959 and R2 = 0.99994 are obtained respectively, which proves that the accuracy of the dual gas sensor is robust. In the dual gas concentration measurement, we carry out continuous measurement of five mixed gases and a long-term measurement of a mixture of gases, which verifies that our sensor has the fast response speed and strong stability. The minimum detectable column densities of 0.62 ppm·m for CH4 and 0.1 ppm·m for C2H6 are achieved, respectively. The CH4/C2H6 dual gas sensor assisted by the correction method has high sensitivity and strong robustness to cross-interference, and has great potential for application in various scenarios.