It is also possible to form multistage emulsions in an oil continuous phase as shown in Figs. If it is a water-in-oil emulsion initially, a water-in-oil-in-water emulsion can be formed if a small volume of the original water-in-oil emulsion is enveloped in a film of water. Uniformly sized oil particles are about 10 µm in diameter and are dispersed in the continuous water phase.Ĭause it to become multistage. 19.2-Photomicrograph of reverse emulsion. Water no gravity london dispersio skin#Observe the riqid-appearing film or skin that retards coalescence.įig. 19.1-Photomicrograph of water-in-oil emulsion. The emulsion may be either water-in-oil or oil-in-water to begin with, but additional agitation mayįig. Emulsions are sometimes interrelated in a more complex form. A typical reverse emulsion is shown in Fig. The oil can be dispersed in the water to form an oil-in-water emulsion, which is referred to as an “inverse” or “reverse” emulsion. This is a water-in-oil emulsion and is referred to as a “normal” emulsion. which compels them to present the smallest possible surface area to the oil. The spherical form of the water globules is a result of interfacial tension (IFT). In most emulsions of crude oil and water, the water is finely dispersed in the oil. The emulsions considered in this chapter consist of crude oil and water or brine produced with it. The portion of the emulsion that is in the form of small droplets is called the internal, dispersed, or discontinuous phase. The matrix of an emulsion is called the external or continuous phase. 19.1, these emulsifying agents form interfacial films around the droplets of the dispersed phase and create a barrier that slows down or prevents coalescence of the droplets. which commonly act as emulsifying agents or emulsifiers. The stability of the emulsion is controlled by the type and amount of surface-active agents and/or finely divided solids. Such inhibition is not present in a dispersion. An emulsion is distinguished from a simple dispersion of one liquid in another by the fact that, in an emulsion, the probability of coalescence of droplets on contact with one another is greatly reduced because of the presence of an emulsifier, which inhibits coalescence. More detailed and diversified discussions on crude oil emulsions can be found in the General References at the end of the chapter.Īn emulsion is a heterogeneous liquid system consisting of two immiscible liquids with one of the liquids intimately dispersed in the form of droplets in the second liquid. This chaptcr contains an abbreviated discussion of only a few of the most important and pertinent considerations of crude oil emulsions. Many topics and sub-topics exist on which entire chapters can be written. procedures, equipment, and systems generally used in treating crude oil emulsions are considered in this chapter, Space limitation does not permit the rigorous trcatment of crude oil emulsions. When water forms a stable emulsion with crude oil and cannot be removed in conventional storage tanks. Salt content along with BS&W are the two importsnt crude purchasing requirements. Removing water from the stream decreases the salt content. Purchasers may also limit the salt content of the oil. These troublesome solids vary widely from producing field to field. The solids contained in the BS&W come from the producing formation and consist of sand. BY&W is usually predominantly water but may contain solids. and contractual agreements and typically range from 0.2 to 3.0%. Limits vary depending on local conditions, practices. To prevent increased transportation costs, water treatment and disposal costs, and deterioration of equipment, purchasers of crude oil limit the basic sediment and water (BSSCW) content of the oil they purchase. Water content of the untreated oil may vary from a fraction of I % to over 90%. water cuts may increase in time to the point where it is necessary to treat the emulsion. Even in those fields where there is essentially no initial water production. Much of the oil produced worldwide is accompanied by water in an emulsion that requires treating. Electronics and Telecommunication Engineering.Electronics and Communication Engineering.
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