Prediction of surface tension of heavy oil based on principle of corresponding states combined with detailed composition and molecular structure analysis

In this work, a new method of predicting the surface tension of heavy oils and its temperature dependence was developed. The surface tensions of five fractions and residue fractionated by the vacuum distillation of atmospheric residue (AR), and AR itself were predicted, based on a detailed composition and molecular structure analysis, i.e., “petroleomics”. In this method, the chemical compositions and molecular structures of compounds included in the fractions and residue were identified by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and then the critical pressure, critical temperature and boiling point of each compound were calculated by the group contribution method. Next, using the calculated properties, the surface tension of each compound was predicted by the principle of corresponding states. Finally, a mixing rule, in which the surface tension of mixtures was expressed as a linear function of mole fraction of each compound, was used to predict the surface tensions of the five fractions and residue of AR and AR itself. By comparing the predicted and experimental values of the surface tensions and their temperature dependence, it was found that the present method is useful for predicting the surface tension of heavy oils.