The Development of an Ionic Liquid-Based Demulsifier for Oil/Water Separation

The petroleum industry produces a huge quantity of wastewater in the form of emulsions that contains a significant fraction of oil. The separation of oil from the produced water is a significant challenge that is being addressed using different types of techniques. Chemical demulsification is one of the most important The application of ionic liquids (ILs) as a demulsifier is considered as an emerging technology in the petroleum industry. The primary objective of this work was to evaluate the performance of the ionic liquids for the demulsification of water in oil ( W/O) emulsions at different conditions such as ILs dosage, structure ( anions, and alkyl chain), and salt concentration. A bottle test was used to measure demulsification efficiency (DE%). Firstly, a crude oil emulsion was prepared with deionized water and oil at a different ratio. The demulsifier was prepared by dissolving ionic liquids in a solvent at specific concentrations. Emulsion characterization was carried out with the average droplet size measurement analysis and rheological analysis. The results from the current experimental work with pyridinium-based ILs with different anions indicate that a higher degree of hydrophobicity improves demulsification. A high temperature of 90ᵒC was used to accelerate the demulsification of W/O crude oil emulsion. Demulsification efficiency of above >95% was obtained with more hydrophobic anions in no time at a concentration as low as 500 ppm. When it comes to structural configurations, the demulsification of the W/O crude oil emulsion was favored by the use of more hydrophobic IL’s containing butyl alkyl chains. The least efficient demulsifier was found to be the one with the shortest alkyl length and the least hydrophobic anion. The involvement of seawater accelerated the separation with all the ionic liquids resulting in high demulsification efficacy of the emulsion. The application of the pyridium class of IL as a demulsifier for the demulsification of crude oil is very rare and scarcely available. This study helps us to carry out a comprehensive analysis of evaluating the available ionic liquid and their ability to carry out efficient separation of water in crude oil emulsions.