Simultaneous detection of H2S and CO based on cantilever enhanced photoacoustic spectroscopy

Cantilever beam enhanced photoacoustic spectroscopy gas detection technology has attracted extensive attention due to its high detection sensitivity, but the quantitative detection of multi-component in mixed gas has not been carried out yet. In this paper, two infrared laser beams with central wavelengths of 1578.13nm and 1568.04nm are coupled into the same optical fiber with a wave combination, and H
2
S and CO are quantitatively detected in binary mixture gas $\mathrm{H}_{2}\mathrm{S}/\mathrm{N}_{2}, \mathrm{C}\mathrm{O}/\mathrm{N}_{2}$ and ternary mixture gas $\mathrm{H}_{2}\mathrm{S}/\mathrm{C}\mathrm{O}/\mathrm{N}_{2}$. Based on the analysis of the cross interference mechanism of infrared absorption S lines, a quantitative detection method of H2S and CO in H
2
S/CO/N
2
termist mixture was proposed, and the influence of background gas types on PAS signal intensity was analyzed. The results show that the maximum SNR values of H
2
S and CO gases both appear at 45Hz in the range of 20-300hz. In mixed gas, there is a linear relationship between the pure PAS signal value and gas concentration. For the terrestrial-mixed gas, the total PAS signal can be regarded as the linear superposition of the respective PAS signals of H
2
S and CO, and H
2
S needs to be quantified first, and then CO. The results provide an idea for multi-component quantitative detection of fault gas in power equipment.