Separated oil phase

Modern analytical ultracentrifuges allow the separation of emulsions to be followed in a quantitative manner. With typical oil-in water (O/W) emulsions, three layers are generally observed (i) a clear aqueous phase (ii) an opaque phase consisting of distorted polyhedral oil droplets and (iii) a clear separated oil phase, resulting from coalescence of the polyhedra. 

The emulsions were prepared on an ultrasonic disperser, coalescence stability was determined from the volume of the separated oil phase after 24 hours. As it is seen from Fig. 6.8, a complete coalescence stability of the emulsions is achieved at surfactant concentrations beyond the CMC. At the same time, the concentration at which the maximum coalescence stability is achieved is not sufficient to provide sedimentation stability of the emulsions. 

Figure 16.3 la). This microfiltration process requires the use of hydrophobic membranes to remove aqueous phase from W/O emulsions [55] or hydrophihc membranes to separate oil phase from O/... 

According to a NMR study by Hamilton and Small (1981) of the solubilization of triolein in lecithin bilayers in excess water the maximum solubility of triolein is about 2.8% (w/w), and beyond this limit the triolein forms a separate oil phase. The triglyceride is solubilized in the bilayer with the glycerol group at the surface. 

Height in the separated oil phase (0-25 is closest to the water interface) BSW (hottom water and solids) in the oil phase ... 

In this set of bottle test data, the water and solids content (BSW) of the separated oil phase has been evaluated as a function of distance from the separated water. The od at the surface (75-100) is in all cases water and solids free. The practical average is identical in all cases because during field testing it is often not possible to extract the entire oil phase for BSW testing. It is the most important part of the sample nearest die water phase (often about 10%) that is not analysed. Without detailed BSW data for the oil, these three demulsifiers would be presumed to have identical performance while in fact, demulsifier 1 has a significant amount of the oil which does not meet the 0.5% BSW pipeline specification. 

Demulsibility of petroleum oils and synthetic fluids NFT 60-125 ISO 6614 ASTM D 1401 Time necessary for separation of phases... 

The preceding treatment relates primarily to flocculation rates, while the irreversible aging of emulsions involves the coalescence of droplets, the prelude to which is the thinning of the liquid film separating the droplets. Similar theories were developed by Spielman [54] and by Honig and co-workers [55], which added hydrodynamic considerations to basic DLVO theory. A successful experimental test of these equations was made by Bernstein and co-workers [56] (see also Ref. 57). Coalescence leads eventually to separation of bulk oil phase, and a practical measure of emulsion stability is the rate of increase of the volume of this phase, V, as a function of time. A useful equation is... 

Most characteristics of amphiphilic systems are associated with the alteration of the interfacial stnicture by the amphiphile. Addition of amphiphiles might reduce the free-energy costs by a dramatic factor (up to 10 dyn cm in the oil/water/amphiphile mixture). Adding amphiphiles to a solution or a mixture often leads to the fomiation of a microenuilsion or spatially ordered phases. In many aspects these systems can be conceived as an assembly of internal interfaces. The interfaces might separate oil and water in a ternary mixture or they might be amphiphilic bilayers in... 

Essences generally are stored separately from the bulk concentrates for stabiHty, and their addition prior to retail packaging is essential to restoring much of the natural fresh flavor of the starting juice otherwise lost during processing. Unlike citms, which affords both an aqueous and an oil-phase essence, only an aqueous-phase essence is obtained for deciduous fmit. Virtually no essential oil is present in the peel or juice in the latter. 

The process of flushing typically consists of the foUowing sequence phase transfer separation of aqueous phase vacuum dehydration of water trapped in the dispersed phase dispersion of the pigment in the oil phase by continued appHcation of shear thinning the heavy mass by addition of one or more vehicles to reduce the viscosity of dispersion and standardization of the finished dispersion to adjust the color and rheological properties to match the quaHty to the previously estabHshed standard. 

Preparation of Emulsions. An emulsion is a system ia which one Hquid is coUoidaHy dispersed ia another (see Emulsions). The general method for preparing an oil-ia-water emulsion is to combine the oil with a compatible fatty acid, such as an oleic, stearic, or rosia acid, and separately mix a proportionate quantity of an alkah, such as potassium hydroxide, with the water. The alkah solution should then be rapidly stirred to develop as much shear as possible while the oil phase is added. Use of a homogenizer to force the resulting emulsion through a fine orifice under pressure further reduces its oil particle size. Liquid oleic acid is a convenient fatty acid to use ia emulsions, as it is readily miscible with most oils. 

In one process the resulting solution is continuously withdrawn and cooled rapidly to below 75°C to prevent hydrolysis and then further cooled before being neutralised with ammonia. After phase separation, the oil phase is then treated with trichlorethylene to extract the caprolactam, which is then steam distilled. Pure caprolactam has a boiling point of 120°C at 10 mmHg pressure. In the above process 5.1 tons of ammonium sulphate are produced as a by-product per ton of caprolactam. 

The other class of phenomenological approaches subsumes the random surface theories (Sec. B). These reduce the system to a set of internal surfaces, supposedly filled with amphiphiles, which can be described by an effective interface Hamiltonian. The internal surfaces represent either bilayers or monolayers—bilayers in binary amphiphile—water mixtures, and monolayers in ternary mixtures, where the monolayers are assumed to separate oil domains from water domains. Random surface theories have been formulated on lattices and in the continuum. In the latter case, they are an interesting application of the membrane theories which are studied in many areas of physics, from general statistical field theory to elementary particle physics [26]. Random surface theories for amphiphilic systems have been used to calculate shapes and distributions of vesicles, and phase transitions [27-31]. 

The decanted aqueous phase was extracted three times with a total of 150 ml of ethyl acetate. The combined organic solutions were filtered over Clarcel and extracted three times with a total of 150 ml of an Iced normal aqueous methane-sulfonic acid solution. The combined acid extracts were rendered alkaline on an ice bath with 30 ml of ION caustic soda solution. The separated oil was extracted four times with a total of 200 ml of ether. The combined ethereal extracts were washed twelve times with a totai of 360 ml of distilled water, dried over anhydrous magnesium sulfate in the presence of 0.3 g of animal charcoal and evaporated under reduced pressure on a water bath at 40°C. The oily residue obtained (3.8 g) was dissolved in 30 ml of boiling acetonitrile. After cooling for 2 hours at 3°C, the crystals formed were separated, washed with 5 ml of acetonitrile and dried at ambient temperature at low pressure. 

The chemical treatment methods reduce dispersability property, of drilling fluids through the increase of size of cuttings which improves separation and prevents the buildup of colloidal solids in the mud. These methods include ionic inhibition, cuttings encapsulation, oil phase inhibition (with oil-base muds), and flocculation. The mechanical solids removal methods are based on the principles presented in Table 4-55. 

Preparation of Emulsions. The entire aqueous phase was stirred until all solids were dissolved. Sufficient water was withheld from the formulation so small volumes of experimental and control components could be added to emulsion subsamples. Sulfuric acid (1 N) was added to the aqueous phase to decrease the pH to 5.7. The two phases in separate containers were blanketed with nitrogen, sealed, and heated to 75 in an 80 water bath (about 30 minutes). The hot oil phase was stirred slowly and blanketed with nitrogen, then the hot aqueous phase was quickly added while stirring. The emulsion was blanketed with nitrogen and slowly stirred (about 2 hours) in the stoppered container until ambient temperature ( 25 ) was reached. Subsamples of the master batch were removed for the addition of experimental components and stored in 1-oz containers. The containers had been washed with hot tap water, deionized water, and methanol, then dried at 120 . 

Since post-addition of oil-soluble inhibitors would not assure their presence in the oil phase of the emulsion, separate emulsions were prepared. 

Each inhibitor was added to the oil phase of each emulsion before heating and combining the water and oil phases. Therefore, positive controls containing no inhibitor could not be made from the same base emulsion. Instead, a separate emulsion batch run simultaneously was used as a positive control. 

Fig. 2.7.6 Left A representation of a Schlum- that dearly separate and correspond to the berger NMR well-logging tool [56], The long oil and water signals, respectively. The lower cylinder is the tool body and the shaded areas peak corresponds to the oil phase, the higher contain permanent magnets. The multiple peak corresponds to the water phase. Note that sensitivity regions are shown as the colored the T2 distribution of the oil and water peaks sheets that are outside the tool body. Right overlap significantly. From the map, a water...

Chemically, the preparation of a "stable" foam or emulsion requires the use of a surfactant to aid in dispersion of the internal phase and prevent the collapse of the foam (or emulsion) into separate bulk phases. The selection of a surfactant is made on the basis of severity of conditions to be encountered, the gas to be entrained (N2, C02, LPG, CH, or air), the continuous phase liquid (water, alcohol, or oil), and half-life of foam stability desired. 

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