Performance of Solvent Mixtures for Non-aqueous Extraction of Alberta Oil Sands

Abstract

Non-aqueous extraction of Alberta oil sands is of great interest to developing an alternative to the current hot-water extraction process to eliminate the tailing ponds. Investigations have been conducted to evaluate the performance of solvent mixtures to extract bitumen from a high-grade oil sands ore. Solvent mixtures of cycloalkane and n-alkanes were studied on the basis of their Hildebrand solubility parameters, which affect bitumen recovery and fine solids migration during the extraction process, and the results were compared to single solvents. Cyclohexane, cyclopentane, and methylcyclopentane were selected as the cycloalkane solvents, and they were studied in combination with n-alkane solvents, such as n-heptane, n-hexane, or n-pentane, to make up a final solubility parameter between 16.65 and 16.45 MPa1/2 for the final solvent mixture. It was observed that the solubility parameter of the solvent mixture has more impact on the migration of fine solids in bitumen than the recovery of bitumen. The amount of fine solids migrating into the bitumen product followed the order of cycloalkane/n-heptane > cycloalkane/n-hexane > cycloalkane/n-pentane.