Asphaltene precipitation from heavy oil mixed with binary and ternary solvent blends

Models are required to predict the onset and precipitation of asphaltenes from mixtures of heavy oil and solvents for a variety of heavy oil applications. The regular solution approach is well suited for this objective but has not yet been tested on solvent mixtures. To do so, the onset and amount of asphaltene precipitation were measured and modeled for mixtures of heavy oil with solvent blends made up from n-alkanes, cyclohexane, and toluene at temperatures of 21 and 180 degrees C and pressures of 0.1 and 10 MPa. Temperature dependent binary interaction parameters (BIP) between the cyclohexane/asphaltene and toluene/asphaltene pseudo-component pairs were proposed to match the data. All other BIP were set to zero. The model with BIP determined from asphaltene precipitation in heavy oil and binary solvents predicted asphaltene precipitation from heavy oil and ternary solvent blends, generally to within the experimental error.