Effect of asphaltene content in bitumen on thermodynamic properties of light hydrocarbons dissolving in bitumen

Solvent recovery from diluted bitumen and froth treatment tailings, produced during the bitumen recovery process for mined oil sands, requires an understanding of the thermodynamic equilibrium and kinetics of solvent dissolution in bitumen. Thermodynamic properties of solvent in bitumen having various asphaltene contents are needed in order to model and improve the solvent recovery process. In this work, the thermodynamic properties of light hydrocarbons in bitumen were investigated using an inverse gas liquid chromatography (IGC) method. Bitumen containing different amounts of asphaltenes (0 wt%, 2.6 wt%, 9.9 wt%, 36.9 wt%, and 53.7 wt%) were used as the stationary phase of the chromatographic column, while light hydrocarbons were injected into mobile phase. The specific retention volumes of the hydrocarbons in bitumen, V-g(0), were measured at different temperatures (333.2 K-393.2 K). Thermodynamic properties of these light hydrocarbons in bitumen, including infinite dilution activity coefficient, gamma(infinity), enthalpy of solution, Delta H-0, heat capacity changes, Delta C-p(o), Gibbs energy change, AG(o), as well as entropy of solution change, Delta S-o, were then calculated based on thermodynamic principles and data obtained from IGC measurements. (C) 2019 Published by Elsevier B.V.