Demulsification of crude oil emulsions using a three-branched betaine type ionic liquid and its demulsification mechanism

In this work, a three-branched betaine type ionic liquid (TESA) with elevated interfacial activity was synthesized to separate water from crude oil emulsions at low temperature. The chemical structure, demulsification performance, and demulsification mechanism of TESA was investigated. The bottle tests exhibited that the dehydration efficiency was 100% with 150 mg/L of TESA for 40 min at 50 °C. TESA was effective in acidic, alkaline, and high salinity conditions. The dehydration efficiency of TESA was more than 95.63% with a wide pH range of 3–11. Furthermore, the dehydration efficiency was 100% with 50000 mg/L of salinity for 20 min at 50 °C. Encouragingly, the dehydration efficiency of TESA was better than that of commercial demulsifiers and reported work. The excellent dehydration efficiency of TESA was ascribed to the elevated interfacial activity, amphipathy, and strong interaction with asphaltenes. As a result, TESA improved the substitution of asphaltenes and considerably reduced interfacial tension, resulting in an unstable interfacial film and leading to demulsification. It indicated that TESA was an effective demulsifier, which promised application in the oil industry.