Investigation of the content of unsaturated hydrocarbons in transformer oils using IR spectroscopy

Abstract

THE PURPOSE. To analyze the current understanding of unsaturated hydrocarbons with double C=C bonds in mineral transformer oils and evaluate the effectiveness of modern methods of controlling the content of these compounds in oils. Develop an instrumental way to control unsaturated compounds in mineral oils by means of IR spectroscopy. Study the change in the content of unsaturated hydrocarbons in oils during thermal degradation. Study the effectiveness of the adsorption purification of oils to remove unsaturated compounds from oils. METHODS. To determine the content in mineral oils of unsaturated hydrocarbons used IR spectroscopy in the near infrared spectral region. Artificial thermal degradation of oils was carried out at temperatures of 100 and 150 ºC. For adsorption purification of oils silica gels brands KSKG, AS230SH, as well as Fuller's Earth adsorbent were used. RESULTS. Spectral range 4750÷4500 cm-1 and method of IR spectra transformation were chosen to control the content of unsaturated compounds with double C=C bonds in the oil. As a result of model experiments, it is clearly demonstrated that the content of unsaturated hydrocarbons increases with increasing degree of thermal degradation of oils. It is shown that adsorption purification has a low efficiency with respect to unsaturated compounds. An algorithm for differentiation of fresh mineral transformer oils produced by hydrocracking technology from the regenerated oils is proposed. CONCLUSION. The highest content of unsaturated compounds is contained in mineral oils produced by technologies other than hydrocracking. Thermo-oxidative impact on oil during its operation leads to an increase in the content of unsaturated hydrocarbons in the oil. The content of unsaturated hydrocarbons in the mineral transformer oil characterizes the degree of degradation of its hydrocarbon base that cannot be recovered during regeneration.