Production of stable emulsions

In heavy oil reservoirs with highly porous sands, cyclic steamflooding may cause the formation of stable emulsions. These emulsions can block the production paths in the wellbore. In steam cycle treatments, a blend of oxy-alkylated alkanolamines and sulfonates showed a dramatic improvement over non-chemically enhanced steam cycles [331]. 

The first step in downstream processing is the separation of the product-rich phase from the second phase and the biocatalyst. This may be simplified if the enzyme is immobilized or if a membrane module is included in the experimental set-up. In the case of emulsion reactors, centrifugation for liquid phase separation is a likely separation process [58], although the small size of droplets, the possibility of stable emulsion formation during the reaction, particularly if surface-active... 

Final separation of water occurs in the FPSU s dedicated crude receiving tanks, where water can be taken oil the bottom by the original VLCCs stripping pumps. A dehydrator can be installed if high water production or stable emulsions occur. 

Research (Fontenot and Schork 1993a, b) indicates that miniemulsion polymerization can provide benefits over the current process technology of conventional emulsion polymerization. Among these are a process which is much more robust to contamination and operating errors, a more uniform copolymer composition when used for copolymerization, and a final product which is far more shear-stable than the product of conventional emulsion polymerization. 

J.S. D Arrigo, Surfactant mixtures, stable gas-in-liquid emulsions, and methods for the production of such emulsions from said mixtures, United States Patent No. 4,684,479 (issued 1987). 

Mouran et al. [105] polymerized miniemulsions of methyl methacrylate with sodium lauryl sulfate as the surfactant and dodecyl mercaptan (DDM) as the costabilizer. The emulsions were of a droplet size range common to miniemulsions and exhibited long-term stability (of greater than three months). Results indicate that DDM retards Ostwald ripening and allows the production of stable miniemulsions. When these emulsions were initiated, particle formation occurred predominantly via monomer droplet nucleation. The rate of polymerization, monomer droplet size, polymer particle size, molecular weight of the polymer, and the effect of initiator concentration on the number of particles all varied systematically in ways that indicated predominant droplet nucleation. 

Experience in class separations and analyses of fossil-derived materials began with the petroleum industry. The literature in this area is far too extensive to review here. Furthermore, petroleum literature deals principally with physical and chemical analyses of distillate fractions which are important to product characteristics. Recently, asphalts have received increased attention since they contain a wide range of known hazardous compounds. Most methods applied to whole samples of petroleum crudes have proven inadequate when dealing with synthetic coal liquids or shale oils because of stable emulsion formation in separation steps caused by larger amounts of inorganic and hydrophilic compounds. 

As mayonnaise contains seven times more oil than water and the emulsion is an oil-in-water type, preparation of a stable mayonnaise emulsion is difficult. Thus, major manufacturers of these products have developed proprietary techniques to achieve this goal. Interactive effects of various factors on the stability of mayonnaise emulsions are not well understood. Therefore, production of stable mayonnaise has remained an art to some degree. Although egg solids are the backbone of a stable emulsion, processing conditions whose interactions are only partially understood play an important role. 

Emulsion properties and stability can be measured by rheological studies and dielectric spectroscopy. Rheological studies include forced oscillation experi ments. The formation of stable emulsions is marked by a sharp increase in the elastic modulus. Water con tent is not a good indicator of emulsion characteristics other than that low water contents (<50%) indicate that an emulsion has not been formed and that the product is entrained water-in-oil. Interfacial measure ments are useful for measuring the film strength of... 

The dispersing ability of phosphorus-containing anionics is made use of in many applications. The sequestering abilities of polyphosphoric acid derivatives and derivatives of phosphonic acids are additional valuable properties for their use as dispersants. Their main task is to secure a stable distribution of particles in suspension. This is a strong demand in the production of photographic emulsions, as well as in the production of recording tapes and disk. 

As we have seen, the stability of foams depends on a wide variety of factors involving several aspects of surface science. The potential importance of liquid crystal (LC) formation to emulsion stability was pointed out in the previous chapter. Not surprisingly, an equally important role for such structures has been identified in foaming applications. Although the phenomenon of LC stabilization of aqueous foams has been recognized for some time, their role in nonaqueous foaming systems has been less well documented. Recently, it has been shown that the presence of a liquid crystalline phase can also serve as a sufficient condition for the production of stable foams in organic systems. 

Globally speaking, one can reason out the difference in the behavior of hand-shaken and sonicated emulsions in terms of the production of stable drop sizes. One would expect the sonicated emulsions to provide a stable equilibrium drop population. In the case of 2 1 emulsions, it is surprising as to why a difference in the separation behavior, in spite of the two modes of emulsionmaking used, is not observed. Probably the power input by the hand-shaking mode is sufficient to produce equilibrium drop population. 

Sc(DS)3 worked well in aldol reactions of various substrates such as -unsaturated, aliphatic, and heterocyclic aldehydes. As for nucleophiles, silyl enol ethers derived from ketones as well as ketene silyl acetals derived from thioesters and esters also reacted well to give the corresponding products in good yields. A key to the success in this system was assumed to be formation of stable emulsions. The size and the shape of emulsion droplets was examined by transmission electron microscopy. 

These are made by adding bromine to the unsaturated fatty acid component of the vegetable oil. The major use of bromi-nated vegetable oils is the production of stable flavor emulsions for use in citrus-flavored soft drinks. They are considered a food additive, and the Food and Drug Administration (FDA) allows citrus and other fruit-flavored beverages to contain only 15 parts per million (ppm). 

Crude oil almost always carries with it some amount of bottom sludge and water (BS W) at a typical concentration of about 0.5 wt %. Sludge comprises a mixture of organic and inorganic products with water in the form of both types of stable emulsions, oil-in-water and water-in-oil. These products include waxes, asphaltenes, polymers, organic acids, salL mud, sand, and corrosion products. 

The presence of these acids in crude oils and petroleum cuts causes problems for the refiner because they form stable emulsions with caustic solutions during desalting or in lubricating oil production very corrosive at high temperatures (350-400°C), they attack ordinary carbon steel, which necessitates the use of alloy piping materials. 

Although most of the particulate in the off-gas from the furnace can be captured by the electrostatic precipitators before condensing the phosphoms, some carryover into the product is inevitable. This particulate is partly separated into the condenser water. The remainder reports to the phosphoms to yield either dirty product or a stable emulsion called phosphoms mud or sludge. Over many years a variety of approaches have been used to minimize the formation of sludge and to recover phosphoms product from the sludge. 

---