An Othmer recirculating still and a standard packed column fractionating unit were used in determining the equilibrium flash vaporization and true boiling point curves respectively, for eight samples of crude oils from producing oil-fields in Alberta. The EFV curves, at 10 mm. absolute pressure were also obtained for these samples. Determinations at atmospheric pressure were used for modifying Okamoto and Van Winkle's correlation, which allows the prediction of the EFV curves from the TBP curves, for application to crude oils. The correlation relates the 50 percent points and the slopes of the two curves. In spite of its simplicity, it results in predicted curves of good accuracy. It is believed that this method is suitable for a large number of crudes and can give dependable phase equilibrium data. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate