Miniaturized methane detection system based on photoacoustic spectroscopy

Aiming at the need of rapid and sensitive detection of acetylene dissolved in oil, a small‐volume T‐type photoacoustic (PA) cell was proposed. By optimizing the design parameters, the volume of the T‐type cell was reduced to 30 mL, which resulted in a significant reduction in the sampling amount of the transformer oil. A laser PA spectroscopy system for dissolved gas analysis was built combined with the headspace degassing method. A near‐infrared tunable laser with wavelength modulation spectroscopy was employed to detect the escaped acetylene gas from oil. Test results show that the detection limit of dissolved acetylene reaches 0.2 μL/L when the sampled oil volume is 50 mL. In addition, the degassing balance time can be shortened to 270 s. This scheme has the superiority of small oil extraction volume, high accuracy, and short response time, providing a new method for analyzing the dissolved characteristic gases in oil.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Rapid detection of dissolved acetylene in oil based on T‐type photoacoustic cell

Wang

Dehui

Yuan

et al. 2023

“…Besson et al 15 built a multicomponent photoacoustic spectroscopy detection device and analyzed the effect of buffer gas on the photoacoustic signal from both theoretical and experimental perspectives. Ye et al 16 designed a miniaturized photoacoustic cell using COMSOL software and obtained methane gas detection sensitivity at ppm level. Liu et al 17 studied the effect of temperature on the resonance frequency of the tuning fork in quartz‐enhanced photoacoustic spectroscopy (QEPAS) and proposed a compensation and calibration method.…”

Section: Introductionmentioning

confidence: 99%

Research on temperature and pressure interference in photoacoustic spectroscopy gas detection

Ye,

Luo,

Liu

et al. 2023

Self Cite

Photoacoustic spectroscopy (PAS) is a highly sensitive optical detection technique for trace gases. However, PAS is sensitive to environmental factors such as temperature and pressure during actual measurement. In this paper, we study the interference characteristics of temperature and pressure in PAS gas detection. The influence of pressure and temperature on PAS is theoretically analyzed based on the basic principle of gas photoacoustic spectroscopy. The effect of different pressure and temperature conditions on the resonance frequency and signal amplitude of PAS is studied through COMSOL software simulation and validated through experiments. Results show that changes in temperature and pressure will affect the resonance frequency and signal amplitude of PAS, thereby impacting the system's sensitivity and accuracy. To reduce the impact of temperature on the PAS sensor, a temperature compensation model was derived based on experimental analysis. Real‐time temperature detection is used to compensate for the photoacoustic signal based on temperature changes, which can improve the accuracy and stability of photoacoustic spectroscopy gas detection. For 5% CO2, the photoacoustic signal and experimental temperature data were measured for 3612 s, and after temperature compensation, the detection limit was 0.0192% at an integration time of 365 s, which is 0.0128% higher than before temperature compensation. The system's normalized noise equivalent absorption coefficient is 3.30 × 10−8 cm−1 WHz−1/2. This research improves the accuracy and reliability of photoacoustic spectroscopy gas detection technology and provides useful references for temperature correction in similar gas detection fields.

Interference characteristics of leaking SF₆ on photoacoustic detection of dissolved C₂H₄ in transformer oil

Mo,

Zhou,

et al. 2024

SF6 leaked from gas insulation equipment will interfere with the detection of dissolved characteristic gases in transformer oil. In order to determine the impact of SF6 on the detection of dissolved C2H4 gas in oil, a photoacoustic (PA) C2H4 detection system based on the combination of mid‐infrared thermal radiation source and near‐infrared laser was constructed. The excitation light from two bands was incident on a non‐resonant PA cell. The thermal radiation light source and the laser light source were switched to evaluate the interference level of SF6 on the detection of C2H4. The experimental results show that SF6 has significant interference to C2H4 when using a mid‐infrared thermal radiation light source. The interference coefficient is 2014%. The near‐infrared laser based on PA detection method can effectively suppress the interference of SF6 on C2H4. The minimum detection limit of C2H4 reaches 0.6 ppm when the average time is 60 s.