Oil mousse

One important area of petroleum emulsions that is not addressed concerns the water-in-oil mousse emulsions created from oil spills at sea. This topic is covered in detail in a hook hy J. R. Payne and C. R. Phillips entitled Petroleum Spills in the Marine Environment The Chemistry and Formation ofWater-in-Oil Emulsions and Tar Balls Lewis Publishers Chelsea, MI, 1985. 

Extract of oak moss. Extract made mainly from Evernia prunastri (oak moss) and Pseudevernia furfuracea (tree moss). Oak moss concrete is prepared by hydrocarbon solvent extraction of the lichen Evernia PrunastrU collected mainly from oak trees in Yugoslavia, France, Italy, Corsica, Morocco, Hungary, and various central European countries. Contains atranorin, evernic acid and usnic acid Synonyms oak moss-resinoid oil Mousse concrete oak moss oak moss extra resinoid colourless MD oak moss LA oakmoss oil oak moss resin oak moss resinoid diethyl phthalate codistillate Evernia furfuraceae spp. absolute tree moss absolute Mousse d arbre absolute Evernia spp. absolute Mousse de chene absolute Evernia furfuraceae spp. concrete Mousse d arbre concrete tree moss concrete Evernia prunasti spp. concrete Evernia prunasti spp. oil Evernia prunasti spp. resin Uses fragrance in many perfume mixtures, after-shave lotions etc. (hay new-mown hay animal fern green). PA... 

Figure 11. Illustration of possible structures in the interface in a water-in-oil mousse emulsion. Some possibilities are, from left to right, stabilized by asphaltenes, by surfactants and waxes, by both, and unstabilized. (From Mackay [147]. Copyright 1987 Environment Canada, Ottawa, ON.)...

FIGURE 4.42 Changes in amount of heavy oil mousse sorbed into three carbon sorbents with time. 

Even though the sorption performance (both capacity and rate) for heavy oil mousse was a bit inferior to that of pure oil, it was experimentally demonstrated that heavy oil mousse can be recovered by using carbon materials. However, the separation of water from heavy oil mousse was not observed throughout the sorption process. 

Analyzes carbon s ability to ab.sorb heavy oils from oil. spills, contaminated sands, and heavy oil mousse... 

Effectiveness of Chemical Dispersants Under Real Conditions. It is believed that the effectiveness of dispersants is influenced by a number of factors, including the chemical natures of the dispersant and the nature of the oil, their relative amounts, and the microscopic mixing processes occurring as the dispersant lands on the oil and penetrates it while subject to turbulence originating in the air and water [1143]. In addition, the oil to be treated can also partly evaporate, form mousses, and spread into thick and sheen patches. 

Demulsifiers (specifically, oil spill demulsifiers) can be applied to oil spills in low concentrations. They prevent mousse formation for significant periods of time and cause a large reduction in oil-water interfacial tension. The best of these was found to prevent emulsification at dosages as low as 1 part inhibitor to 20,000 parts of fresh oil at 20° C [273]. At dosages of 1 1000, at temperatures higher than 10° C, the chemical also results in significant and rapid dispersion of the oil. For very low temperatures or highly weathered oil, the performance of the chemical falls off sharply. 

Certain oils tend to form water-in-oil emulsions (where water is incorporated into oil) or mousse as weathering occurs. This process is significant because, for example, the apparent volume of the oil may increase dramatically, and the emulsification will slow the other weathering processes, especially evaporation. Under certain conditions, these emulsions may separate and release relatively fresh oil. Most of this process occurs from about half a day to two days after the spill. 

The density of crude oil is on the order of 0.85 g/cm, so if the sea surface is calm, an oil spill will initially form a slick. The slick is subject to physical processes, such as advection and turbulence, causing it to move vertically and/or horizontally. Advection tends to lead to dispersal or, if land is nearby, shoreline stranding. Turbulence promotes the formation of emulsions, called chocolate mousse, which can be transformed via weathering into tarballs. The lower-molecular-weight compounds tend to evaporate or dissolve. Some fractions of petroleum have solubilities in seawater on the order of tens of milligrams per liter. Some are also photochemically oxidized. 

Emulsification. This is a water-in-oil process in which water is incorporated into the floating oil. Such emulsions, which may contain from 20 to 80% water, are often very viscous and referred to as mousse. Mousse formation is highly dependent on oil composition. High levels of asphalt-type compounds, as well as waxes, appear to promote the formation of these emulsions. Ocean turbulence also accelerates mousse formation, although a fully developed, stable emulsion may be formed from some oils under relatively quiescent open-water conditions. Early treatment of spilled oil with chemical dispersants is an excellent way to prevent emulsification. 

Some special problems arise at sea. When crude oil is spilled on the ocean, a slick is formed which spreads out from the source with a rate that depends on the oil viscosity. With sufficient energy an O/W emulsion may be formed, which helps disperse oil into the water column and away from sensitive shorelines. Otherwise, the oil may pick up water to form a water-in-oil emulsion, or mousse ( chocolate mousse ). These mousse emulsions can have high water contents and have very high viscosities, with weathering they can become semi-solid and considerably more difficult to handle, very much like the rag-layer emulsions referred to above. The presence of mechanically strong films makes it hard to get demulsifiers into these emulsions, so they are hard to break. See Chapter 9. 

The combined influences of solubilization, evaporation, and oxidation are known as weathering. Weathering preferentially removes the lighter hydrocarbon fractions, leaving a residual material made up of relatively heavy hydrocarbons. Over the shorter term in aquatic environments, this residuum forms a stable water-in-oil emulsion known as mousse, which is the material that usually impacts shorelines after an offshore spill. The mousse combines with sediment particles on the shore to form sticky patties of oil and sand, which eventually form asphaltic lumps. 

Mousse— A water-in-oil emulsion that is formed by turbulence of the surface water after a petroleum spill to the aquatic environment. 

Finally, many kinds of emulsions pose difficult problems wherever they may occur. For example, crude oil when spilled on the ocean tends to become emulsified in the form of chocolate mousse emulsions, so named for their color and semisolid consistency. These water-in-oil emulsions with high water content tend to be quite stable due to the strong stabilizing films that are present. Mousse emulsions increase the quantity of pollutant and are usually very much more viscous than the oil itself. 

A graphic and important example is furnished by the oil spill chocolate mousse emulsions formed when crude oil spills into seawater. These water-in-oil emulsions have high water contents that may exceed 74% and reach = 0.80 or more without inverting. As their common name implies, these mousse emulsions not only ha e viscosities that are much higher than the original crude oil but can become semisolid. With increasing time after a spill, these emulsions weather (the oil becomes depleted in its lower boiling fractions), and apparently the emulsions become more stable, more solidlike, and considerably more difficult to handle and break. 

Chocolate Mousse Emulsion A name frequently used to refer to the water-in-oil emulsions having a high water content that are formed when crude oils are spilled on the oceans. The name reflects the color and very viscous consistency of these emulsions. It has also been applied to other petroleum emulsions of similar appearance. 

Emulsification is the process by which one liquid is dispersed into another one in the form of small droplets. Water droplets can remain in an oil layer in a stable form and the resulting material is completely different. These water-in-oil emulsions are sometimes called mousse or chocolate mousse as they resemble this dessert. In fact, both the tastier version of chocolate mousse and butter are common examples of water-in-oil emulsions. 

Chocolate mousse — Used to describe a water-in-oil emulsion consisting of 50 to 80% water. These emulsions are sometimes stable and range in consistency from grease-like to solid. They are only formed with a relatively viscous oil in the presence of considerable wave action. (See also Emulsification, Water-in-oil emulsion.)... 

Emulsification — The process whereby one liquid is dispersed into another liquid in the form of small droplets. In the case of oil, the emulsion can be either oil-inwater or water-in-oil. Both types of emulsions are formed as a result of wave action, although water-in-oil emulsions are more stable and create special cleanup problems. (See also Chocolate mousse, Oil-in-water emulsion, Water-in-oil emulsion.) Emulsion breakers and inhibitors — Chemical agents used to prevent the formation of water-in-oil emulsions or to cause such emulsions to revert to oil and water. Several formulations can perform both functions. 

In order to illustrate the range of application strategies chocolate mousse, fuel oil spill etc.) that are closely related to the chemical structures of the respective crude oil fractions, examples are summarised in Table 2 that stem from the ARCHIMEDES experiments carried out in the German Bight in 1983 and 1985 (Commission 1985). 

---