WATER-IN-OIL EMULSION FORMATION - A REVIEW OF PHYSICS AND MATHEMATICAL-MODELING

A literature review of the physics and modelling of water-in-oil emuls ification is presented. The understanding of the physics of emulsion f ormation is still incomplete, but developing. The formation of emulsio ns is due to the surfactant-like action of polar compounds (resins) an d asphaltenes in oil. These compounds act to maintain small (1-20 mu m ) droplets of water in oil. Volatile aromatic compounds in crude oils solubilize asphaltenes and resins. Crude oils containing lower quantit ies of these volatile compounds or BTEX (benzene, toluene, ethylbenzen e, xylenes) will form emulsions given sufficient turbulent sea energy. Oils may lose the BTEX component by weathering before being capable o f forming stable emulsions. The kinetics and energy of formation of em ulsions is not well understood. Emulsions are often reported to form r apidly after the necessary chemical conditions are achieved and where there is significant wave action or other turbulent energy. Oil spill models generally employ a first-order rate law (exponential) to predic t emulsion formation.