A high-throughput method for screening surfactant additives and structure–property relationships for the removal of water from bitumen

This paper describes the development of a new high-throughput (HT) method for screening surfactant additives for the removal of water from bitumen extracted from oil sands. The method begins by isolating bitumen froth from Canadian oil sands via the hot water extraction and flotation process. The froth is then diluted with naphtha to form “dilbit” The dilbit is homogenized and subsequently mixed twice to ensure a uniform distribution of water and sediment. Then, aliquots of the dilbit are dispensed into separate vials, and surfactant additives are mixed in at the desired concentrations. Next, the samples are transferred to centrifugation cells and centrifuged. Finally, the top third of the sample volume is removed, and Karl Fischer titration is used to measure the residual water. The HT method was used to screen the dewatering performances of 67 surfactants. Of the surfactants screened, (ethylene oxide)-(propylene oxide)-(ethylene oxide) (EO_x-PO_y-EOx) triblock copolymer surfactants with molecular weight (MW) values >2000 Da and hydrophilic–lipophilic balance (HLB) values <16 were found to be the most effective demulsifying additives. The research approach presented here may enable the rapid development of structure–property relationships to guide the selection of surfactant additives for the improvement of commercial bitumen froth extraction and upgrading processes.