A dielectric investigation of structural-phase transitions in oils

The article deals with issues related to the mechanism of solidification of oils. The authors present the results of a dielectric investigation of structural-phase transitions in oils from the fields of Tyumen region in the temperature range -110 ÷ +20 °С. The dielectric relaxation of oils has been established, the values of the activation energy and dielectric relaxation time have been calculated. The phase transition determined by dielectric relaxation is interpreted as a transition from the glassy state to the associated state. The glass transition of oils, accompanied by the cessation of internal rotation in hydrocarbon molecules, is a sign of their true (or viscous) solidification. The glass transition temperature and the temperature region of the structural solidification of oils were determined. The glass transition temperature is considered to be the true pour point. The relationships between the physicochemical characteristics of oils and the parameters characterizing their dielectric properties were established, which were studied by the methods of correlation and regression analysis. The obtained regression equations can be used to predict the physico-chemical characteristics of oils in the technological processes of their extraction, field preparation and transportation.