Solubility Modeling of Asphaltenes in Organic Solvents

The solubilities of Athabasca asphaltenes in a variety of organic solvents are measured and compared with predictions using a solid−liquid equilibrium calculation based on Scatchard−Hildebrand solubility theory with a Flory−Huggins entropy of mixing. The necessary input for the calculation is the feed composition and the component molar volumes and solubility parameters. Previously determined molar mass distribution and property correlations are used to calculate the necessary asphaltene input. The solvent properties are obtained from published data. Both single solubility parameter and three-component solubility parameter models successfully predict asphaltene solubility in a variety of nonpolar and slightly polar organic solvents, including normal and branched alkanes, aromatics, dichloromethane, Decalin, and 1-hexene. The single-component solubility parameter model cannot accurately predict asphaltene solubility in highly polar solvents, and qualitative predictions, at best, are obtained from the three-component model.