Determination of aromatic hydrocarbons in electrical insulating oils - Oil, Gas & Refineries
Introduction
One of the most widespread liquid electrical insulating materials is transformer oil. It is used to fill the pores in the fiber insulation and the space between the windings, thereby increasing the dielectric strength of the insulation and improving the heat removal from the windings and the core of a transformer.
The oil is also used in high-voltage current breakers. The most important quality parameters of insulating oils are their dielectric properties, fast heat transfer and moisture resistance. The insulating oil is produced during crude oil refining, and the foreign impurities should be removed from the oil distillate, in particular, aromatic hydrocarbons that decrease oil resistance to oxidation, its dielectrical properties and fluidity at low temperatures.Therefore, regulations impose limit on the concentration of aromatic hydrocarbons in the electrical insulating oils.
The infrared spectroscopic methods provide monitoring of the aromatic hydrocarbon content in insulating oils in a range of 1.2–60%. Basing on the results of analysis, one can promptly respond to degradation of the quality parameters during the process of oil production, as well as ensure the high quality of the final product and prove-in performance. Infrared spectroscopy may also be used for quality control of mineral insulating oil.
A sealed liquid cell is filled with the analysed sample and is installed in the cell compartment of an InfraLum FT-08 FTIR spectrometer. Infrared spectrum of the sample is recorded in the range of 1700–1500 cm -1 , with resolution of 2 cm -1 and scanning time of 60 s.