(83e) Importance of Solubility Parameter Model for Prediction of Asphaltene Precipitation with Regular Solution Theory
Here, we discuss the effect of solubility parameter calculations on the regular solution model. We perform two different models to calculate the solubility parameter of a solvent for the regular solution model of asphaltene precipitation from bitumen mixed with n-alkane solvents. The two methods in question are the thermodynamic (Hildebrand) equation  and a linear model . The Hildebrand equation for the solubility parameter produces results that disagree with the correlation between temperature and precipitation yield shown in experimental data. The latter method proposes a linear model for the solubility parameter, however, which follows the same temperature trend as the experimental data. The model is linear with respect to temperature and contains the solubility parameter for the solvent at 25 Â°C (Î´25) as a parameter utilized for the final fitting of the model to the experimental data. The tested solvents for the model are n-heptane and n-pentane, for which the determined Î´25 values are 7.33 (cal/cm3)0.5 and 6.82 (cal/cm3)0.5, respectively. These solubility parameters maintain validity for various oil samples and temperatures. The drastic effect of the solubility parameter model and its model parameters illustrate the complexity caused by the increased presence of asphaltenes in heavy oil and bitumen samples.
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Acknowledgement: We gratefully appreciate the Schneider Electric internship program.