Quantitative detection of H2S and CS2 mixed gases based on UV absorption spectrometry

Abstract

H₂S and CS₂ are the decomposition components of insulating gas SF₆. The detection of these two gases is significant for the online monitoring and fault diagnosis of SF₆ electrical equipment. In this study, an ultraviolet (UV) differential optical absorption spectrometry (UV-DOAS) platform is established for detecting the concentration of H₂S and CS₂ mixed gases. Based on the platform, we obtained the UV absorption spectra of the two gases. The linear relationship between each gas absorption spectra and the concentration was established by wavelet processing and frequency analysis. The interference between the two gases in the UV spectrum region was studied. H₂S at different concentrations had little effect on the UV absorption spectra of CS₂. The linearity (R²) of CS₂ inversion formula was 0.9997. CS₂ above 50 ppb produces a great interference on H₂S concentration detection. CS₂ concentration has a linear relationship with the H₂S concentration inversion; hence, the H₂S correction formula with CS₂ concentration as the variable is proposed. With the correction formula, the linearity (R²) of H₂S inversion formula reaches 0.9994 in mixed gas detection, which can meet the H₂S and CS₂ mixed gases quantitative detection.