Demulsification of Crude Oil-in-Water Emulsions Driven by Graphene Oxide Nanosheets

During its production most crude oil occurs as a water-in-oil emulsion whose continuous phase depends on the water to oil ratio, the natural emulsifier systems contained in the oil, and theorigin of the emulsion [1]. The emulsifiers are complex chemically and as new oil fields are developed, and as production conditions change in older fields, there is a constant need for new, effective demulsifiers. Demulsification of crude/heavy oil-water emulsion is a major issue thatreceived sustained attention for decades in the petroleum industry [2]. Many strategies including the gravity separation, coalescence technology filtration/membrane separation, absorption, air flotation, coagulation sedimentation, electrolysis process, ultrasonic treatment, and biological treatment etc. have been widely adopted to separate the oil from the O/W emulsions [3,4].However, most of the separation technologies are high costly, energy intensive, complex, and time-consuming. Therefore the addition of chemical demulsifiers is the most widely used method. The process is evaluated using some conventional techniques such as interfacial tensiometry, Dynamic Light Scattering (DLS), and bottle test. Graphene oxide sheets, normally referred as graphene oxide (GO), are the liquid phase oxidation-exfoliation product of graphite.In form of graphene sponge and mesh, graphene is often used to absorb or filter oil based on its low surface energy, low density and high surface area. In this work an amphiphilic material, graphene oxide nanosheets (GO), was introduced as a versatile demulsifier to break up the oil-inwateremulsion at room temperature. It was encouraging to find that the small oil droplets in the emulsion quickly coalesced to form the oil phase and separated with the water within a few minutes. Operating condition was investigated and optimized by studying effect of the GO dosage and interfacial tension on the demulsification As an environmental friendly and high efficient demulsifier, GO might find its application in separating oil from the O/W emulsion in the petroleum industry.

کلیدواژه ها:

demulsifier ، graphene oxide nanosheets (GO) ، interfacial tension (IFT) ، Crude oil