![]() ![]() There are three types of emulsion instability: flocculation, where the particles form clumps creaming, where the particles concentrate towards the surface (or bottom, depending on the relative density of the two phases) of the mixture while staying separated and breaking and coalescence where the particles coalesce and form a layer of liquid.Įmulsion is also a term used in the oil field as untreated well production that consists primarily of crude oil and water. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion tends to imply that both the dispersed and the continuous phase are liquid. Fluid emulsions can also suffer from creaming, the migration of one of the substances to the top of the emulsion under the influence of buoyancy or centripetal force when a centrifuge is used.Įmulsions are part of a more general class of two-phase systems of matter called colloids. This phenomenon is called coalescence, and happens when small droplets recombine to form bigger ones. Homemade oil and vinegar salad dressing is an example of an unstable emulsion that will quickly separate unless shaken continuously. Surface active substances ( surfactants) can increase the kinetic stability of emulsions greatly so that, once formed, the emulsion does not change significantly over years of storage. Over time, emulsions tend to revert to the stable state of oil separated from water. Energy input through shaking, stirring, homogenizers, or spray processes are needed to form an emulsion. Emulsions are unstable and thus do not form spontaneously. Emulsification is the process by which emulsions are prepared.Įmulsions tend to have a cloudy appearance, because the many phase interfaces (the boundary between the phases is called the interface) scatter light that passes through the emulsion. In milk and cream, oil is dispersed within a continuous water phase (an oil-in-water emulsion). In butter and margarine, a continuous liquid phase surrounds droplets of water (a water-in-oil emulsion). Examples of emulsions include butter and margarine, milk and cream, espresso, mayonnaise, the photo-sensitive side of photographic film, and cutting fluid for metal working. One substance (the dispersed phase) is dispersed in the other (the continuous phase). ![]() The results obtained in this study have exposed the capability of the chosen emulsifier as another promising method for stabilizing w/o emulsions.An emulsion is a mixture of two immiscible (unblendable) substances. Moreover, the emulsion with the higher water volume fraction (40%) and emulsifier concentration of 2.5 % indicated higher dynamic viscosity.However, in all types of the samples, the dynamic viscosity decreased by increasing the shear rate. To determine the dynamic viscosity rate, the temperature was varied from 30 ✬ to 90 ✬ and shear rate from (17 to 85)1/sec respectively. The emulsions stabilized with Span 80 obtained a visually stable emulsion in both concentrations of emulsifier and volume fractions of dispersed phase (water) in a period of one week,and there was no water separation was observed in this period. According to the result of microscopy images, the steric stability was obtained in low water volume fraction content (20%), with the smaller droplet sizes and at higher surfactant concentration (2.5%). %) emulsifier at different water: oil ratio of (20-80 vol. The emulsion was stabilized by (1.5 and 2.5 vol. %) heavy and light crude oil was first characterized in terms of physico-chemical properties. The present work is aimed to investigate the stability mechanisms of water-in-crude oil emulsion stabilized by a non-ionic emulsifier (Span 80). There is a wide range of scientific literature related to emulsion stability, most of them dealt with water-in-oil (W/O) or oil-in-water (O/W) type. ![]()
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