Understanding molecular interactions and interfacial behaviors of asphaltenes towards development of an integrated bitumen recovery and upgrading process

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Asphaltenes are normally defined as the part of the crude which is soluble in toluene and insoluble in alkanes, usually n-pentane or n-heptane. The presence of asphaltenes has significant influence on the entire processing of bitumen, from extraction to refinery. For in situ extraction of bitumen using steam assisted gravity drainage (SAGD) operations, asphaltenes are generally believed to stabilize oil-water emulsions, and can prohibit efficient water recovery and cause fouling to equipment and pipes thereby resulting in corrosion and clogging. To address these challenging issues, oil sands industry is developing an improved and integrated in situ bitumen recovery and upgrading process, aiming to combine oil-water-mineral solids separation, solvent de-asphalting and fractionation (and optionally, thermal racking and olefin conversion) into one integrated processing unit. In this new process, suitable paraffinic solvents will be used as diluent to enhance the separation of oil and water and facilitate the removal of the undesired and problematic asphaltenes, solids and water, promote the transport/separation of asphaltenes for other uses, and produce oils of much higher quality while significantly reducing operating cost and the environment impact of bitumen production. The proposed project aims to elucidate the stability and molecular interaction mechanisms of asphaltenes in complex fluid media and their interfacial properties at water/oil/mineral solid interfaces, and understand the selection and impact of suitable paraffinic diluent, through an innovative approach of combining molecular & surface force measurements and molecular dynamics simulations, which will be critical for the successful development of the above integrated process for bitumen extraction and upgrading for the Canadian oil sands industry.