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

Abstract

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.