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

加拿大拥有世界第三大石油储量，仅次于沙特阿拉伯和委内瑞拉的油砂储量。目前的水基油砂采油工艺面临着日益紧迫的环境问题，即高淡水需求、高能耗和高温室气体排放，以及大面积的尾矿库。在所谓的非水萃取(NAE)过程中，使用有机溶剂取代水的研究一直在获得势头，因为NAE过程可能不消耗淡水，产生干燥的尾矿，并导致低温室气体排放。然而，可行的NAE工艺的关键挑战之一是生成的沥青产品的质量，其矿物固体含量不应超过0.03wt%。在NAE过程中，油砂中的细小矿物固体，特别是粘土矿物，往往会迁移到沥青溶剂产品中。以前的研究表明，在沥青-溶剂产品中加入少量的水(如油砂中天然存在的共生水)，可以促进亲水性和双湿细矿物固体的去除，但不能去除疏水的细矿物固体。目前还没有一种有效、经济的方法来去除这些细小的固体物质来满足产品质量要求。在这项研究中，我们建议调节固体/溶剂和溶剂/水界面的界面化学，通过添加具有所需官能团的两亲性化学品和/或生物启发(例如贻贝启发)聚合物来改变细矿物固体的表面润湿性及其与水滴的相互作用。预计这些处理将促进细固体与水滴的聚集。使用先进的纳米机械工具将阐明矿物固体、水滴和沥青-溶剂产品中添加的化学剂之间的基本表面相互作用机理。预计拟议的研究将为油砂行业提供一种有效和经济的方法来去除疏水沥青涂层的细固体，使其离商业上可行的NAE工艺更近一步。

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.