Comparative Study on Electrical Properties of Alkyl Benzene-Insulating Mineral oil Mixtures

D. I. Osman¹, A. H. Salama², S. El-Ezbewy³, G. H. El-GemEie³ R. I. Abdallah¹ and A. R. Taman¹

¹Egyptian Petroleum Research Institute, Nasr City, Cairo, (Egypt) ²National Research Center, Dokky, Cairo, (Egypt) ³Faculty of Science, Helwan University, (Egypt)

The production of insulating mineral oil from Suez naphthenic fraction (b.r. 300-420°C) was carried out by furfural solvent extraction at solvent/oil ratio 4:1 and a temperature70°C. The obtained raffinate was treated with activated alumina. The chemical structure of the refined oil was studied by using standard method of analysis. Naphthenic refined oil and its binary mixtures with alkyl benzene (ethyl benzene and cumene) at different concentrations have been employed as insulating oil in a wide variety of electrical equipment. The electrical properties involving the study of the variation of dielectric constant, dielectric loss, power factor and the conductivity with frequency (100Hz-5MHz) at different temperatures (30-70°C) were also studied. The activation enthalpy DHe, entropy change DSe were calculated for the polarization process. Furthermore the activation energy for the conductance was also calculated. The electrical and physical properties of the mineral refined oil and its binary mixtures indicate the improvement in the characteristics of the naphthenic mineral oil for insulating performance.

Electrical properties; insulating oil; mineral oil; solvent extraction; Naphthenic oil