SO2 Gas Concentration Detection System Combined with Photoacoustic Spectroscopy Technology

Abstract

Traditional photoacoustic spectroscopy uses a microphone as a photoacoustic detector in SO2 gas concentration detection. The signal response will be affected by environmental factors, which will affect system stability. This paper builds a cavity enhanced photoacoustic spectroscopy technology gas detection system, so as to improve SO2 gas concentration detection effect and system stability. For the cavity enhanced photoacoustic spectroscopy gas detection system and the influence of buffer gas on photoacoustic resonance frequency, helium with high sound velocity property is used as buffer gas to compensate for the drift of resonance frequency. Moreover, this paper builds a CE-PAS gas detection system to test the SO2 gas concentration. The experimental results show that the sensor has four orders of magnitude linear dynamic range (1.2 ppb-10ppm) and 1.37 x10-11 W • cm-1Hz-1/2 NNEA, which can be used for high-sensitivity SO2 detection. In addition, the long-term stability experiment shows that the signal fluctuation of the system for the same standard SO2 gas is within ±2%, which verifies the reliability of the technology and the stability of the system. Therefore, this study can provide more reliable technical support for subsequent SO2 gas concentration detection, and can also provide technical reference for the monitoring of other gas concentrations.