Removal of hydrophobic bitumen-coated fine solids from NAE bitumen using water droplets with modified interfacial chemistry and bio-inspired polymers

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Canada has the third largest oil reserves in the world after Saudi Arabia and Venezuela in the form of oil sands. The current water-based oil extraction processes from the oil sands are plagued with increasingly pressing environmental problems, namely high fresh water demand, high energy consumption and GHG emission, and large areas of tailings ponds. Research on replacing water using organic solvents, in a so-called nonaqueous extraction (NAE) process, has been gaining momentum as the NAE process potentially consumes no fresh water, generates dry tailings, and leads to low GHG emission. However, one of the key challenges in a feasible NAE process is the quality of the generated bitumen product, which should contain no more than 0.03 wt% mineral solids. The fine mineral solids in the oil sands, particularly clay minerals, tend to migrate to the bitumen-solvent product during the NAE process. Previous research has shown that a small amount of water (such as connate water naturally present in the oil sands) in the bitumen-solvent product could facilitate the removal of the hydrophilic and bi-wet fine mineral solids, but could not remove the fine hydrophobic bitumen-coated mineral solids. There is currently no efficient and economic method to remove these fine solids to meet the product quality requirement. In this research, we propose to modulate the interfacial chemistry of solid/solvent and solvent/water interfaces to alter the surface wettability of fine mineral solids and their interactions with the water drops, through the addition of amphiphilic chemicals with the desired functional groups and/or bio-inspired (e.g. mussel-inspired) polymers. It is anticipated that these treatment will facilitate the aggregation of the fine solids with water drops. The fundamental surface interaction mechanisms among mineral solids, water drops, and added chemical agents in bitumen-solvent product will be elucidated using advanced nanomechanical tools. It is expected that the proposed research will provide an effective and economic approach to the oil sands industry for the removal of the hydrophobic bitumen-coated fine solids, making it a step closer to a commercially feasible NAE process.