Emulsified oil droplets

Whey protein concentrate. The whey protein used was prepared by ultrafiltration and spray drying. Protein content (N x 6.55) was 68% (dry weight). Lipid content was 7.1% (dry weight). In order to study heat induced aggregation by spectrophotometric methods the turbidity of the dilute protein dispersions was too high. The turbidity of whey protein dispersions is caused by lipids associated with proteins probably in the form of emulsified oil droplets. This fraction was removed by precipitation at pH 4.5 from dispersions made in dist. water and separated by centrifugation at 40 000 xg. 

The interactions between an oil phase and foam lamellae are extremely complex. Foam destabilization in the presence of oil may not be a simple matter of oil droplets spreading upon foam film surfaces but may often involve the migration of emulsified oil droplets from the foam film lamellae into the Plateau borders where critical factors, such as the magnitude of the Marangoni effect in the pseudoemulsion film, the pseudoemulsion film tension, the droplet size and number of droplets may all contribute to destabilizing or stabilizing the three phase foam structure. 

Figure 4. Photomicrograph of an enhanced oil recovery process foam containing emulsified crude-oil droplets. The droplets have traveled within the narrow lamellae to accumulate and sometimes coalesce in the plateau borders of the foam, where they are held preferentially. The presence of such emulsified oil droplets in the foam structure has a destabilizing effect on the foam.

Oil properties are the crucial factor for separation and removal from water. Compounds in the oil, such as resins, asphaltenes, and waxes, contribute to the formation of stable emulsions (10,11). Nickle porphyrin in seawater is a stabilizing component in oil (13). Changes in density and viscosity, the formation of stable emulsions, and the dispersion of oil and emulsified oil droplets, all play important roles in inhibiting of an effective separation of both oil and emulsion droplets in water and water droplets from an emulsion (14). 

In type I microemulsion, the emulsified oil droplets are carried forward and are coalesced with the oil ahead to form an oil bank. In type II microemulsion, it is easy for the external oil to merge with residual oil to form an oil bank. 

Huang and Yu (2002) observed that emulsification was not completely reversible. When the dynamic IFT reached ultralow, emulsification occurred. Even when dynamic IFT went up, emulsified oil droplets did not easily coalesce. In alkaline flooding, emulsification is instant, and emulsions are very stable. From this emulsification point of view, the dynamic minimum IFT plays an important role in enhanced oil recovery. From the low IFT point of view, we may think we should use equilibrium IFT because reservoir flow is a slow process. However, the coreflood results in the Daqing laboratory showed that when the minimum dynamic IFT reached 10 mN/m level and the equilibrium IFT was at 10 mN/m the ASP incremental oil recovery factors were similar to those when the equilibrium IFT was 10 mN/m (Li, 2007). One explanation is that once the residual oil droplets become mobile owing to the instantaneous minimum IF F, they coalesce to form a continuous oil bank. This continuous oil bank can be move even when the IFT becomes high later. Then for this mechanism to work, the oil droplets must be able to coalesce before the IFT becomes high. It can be seen that it will be more difficult for such a mechanism to function in field conditions rather than in laboratory corefloods. This mecha-... 

The ability of the bath to emulsify the oily soil is, however, in itself insufficient to keep all the soil from redepositing on the substrate (Schwartz, 1972). When the emulsified oil droplets impinge on the substrate, some of them may adhere to it in part, with the adhering portion tending to assume the equilibrium contact angle, unless the latter is 180° (i.e., unless complete oily soil removal by roll-back has been attained). This is in contrast to solubilization, which can result in complete removal of the oily soil from the substrate. 

With the surfactant-cosurfactant system, it has been observed (6) that the best oil displacement efficiency is achieved when the surfactant system spontaneously emulsifies with the oil, followed by rapid coalescence of the emulsified oil droplets (2). 

In MOST APPLICATIONS IN THE PETROLEUM INDUSTRY, such as in steam-foam flooding, aqueous foams are used to control flow resistance, and this capability makes them attractive for mobility control for improving oil recovery. When the surfactant solution comes in contact with oil in the porous medium, oil is emulsified, and Figure 1 shows the presence of emulsified oil droplets inside of a capillary network. The oil has... 

The microvisual experiments of Roberts et al. (53) and Schramm et al. (37, 40, 47) showed that foam destruction was associated with the ability or degree of emulsified oil droplets to travel within the foam lamellae. For example, on the basis of the work of Schramm et al., the frequency of... 

Figure 1.5 Example of a petroleum industry foam containing emulsified oil droplets. Photomicrograph by the author.

FIGURE 4.2 Example of a foam containing emulsified oil droplets. (From Schramm and Kutay [15]. Reprinted with the permission of Cambridge University Press.)... 

Plant protection agents such as pesticides and insecticides are more often than not insoluble in water. They are usually dissolved in emulsified oil droplets in water. In view of environmental sustainability, in the newer generation of paints and lacquers the apolar pigments are dissolved in the oily droplets of emulsions so that these paints can be diluted and manipulated using water instead of organic solvents. 

Figure 30 Schematic representation of swollen, cross-linked, hydrophobically modified, cationic acrylate thickener stabilizing an emulsified oil droplet. 

A visual inspection of contaminated fuel taken from a storage tank and allowed to settle in a clear storage bottle would show no visible change in the upper and middle portion of the fuel. There may be a moisture haze layer in fuel above the fuel/water interface. Fragments of hyphae may be present between the moisture haze layer and the fuel/water interface. Immediately above the fuel/water interface there may be a layer of emulsified oil droplets. At the interface, one would see a thick layer of microbial slime. The water bottom may be turbid and black with a strong hydrogen sulfide odor (Smith, 1991). 

As mentioned in Chapter 12 multiple emulsions are complex systems of Emulsions of Emulsions . Two main types can be distinguished water-in-oil-in-water (W/O/W) multiple emulsions, whereby the dispersed oil droplets contain emulsified water droplets, and oil-in-water-in-oil (O/W/O) multiple emulsions, whereby the dispersed water droplets contain emulsified oil droplets. The most commonly used multiple emulsions in pharmacy are the W/O/W, which may be considered as water/water emulsions, whereby the internal water droplets are separated from the outer continuous phase by an "oily layer (membrane). 

Figure 2.7. Illustration of a macroemulsified oil system. The drainage of the film may be reduced due to accumulation of emulsified oil droplets within the plateau borders. The formation of the emulsion film and pseudo-emulsion film are indicated. Factors effecting the foam stability were found to be oil volume fraction, drop size and oil phase density (from ref. (4))...

Microencapsulation by coacervation is a common method for microcapsules production. It can be achieved by employing different methods, where the most common one is formation of an insoluble complex of two oppositely charged polymers and its subsequent deposition at surface of dispersed particles (e.g. emulsified oil droplets). In this way, microcapsules with coacervate shell are formed. Composition and microstructure of the coacervate shell are key to determine properties and application of microcapsules. 

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