Water emulsion test

Phase Inversion The phase inversion of brine/oil/surfactant systems was established routinely by measuring solution conductivity employing a Jenway FWA 1 meter and cell. The process identifies the range over which a large decrease in conductivity occurs as the sytem under test is converted from an oil in water emulsion to a water in oil emulsion. Phase... 

Onium salts, such as tetraethylammonium bromide (TEAB) and tetra-n-butylammonium bromide (TBAB), were also tested as PTCs immobilized on clay. In particular, Montmorillonite KIO modified with TBAB efficiently catalyzed the substitution reaction of a-tosyloxyketones with azide to a-azidoketones, in a biphasic CHCI3/water system (Figure 6.13). ° The transformation is a PTC reaction, where the reagents get transferred from the hquid to the solid phase. The authors dubbed the PTC-modified catalyst system surfactant pillared clay that formed a thin membrane-hke film at the interface of the chloroform in water emulsion, that is, a third liquid phase with a high affinity for the clay. The advantages over traditional nucleophilic substitution conditions were that the product obtained was very pure under these conditions and could be easily recovered without the need for dangerous distillation steps. 

Other emulsion test methods are used to rate the ability of fuel to shed water. These methods include ASTM D-1401 and the Waring Blender Test. The ASTM D-1401 method is a lubricant test method, but has been adopted by the U.S. military for rating diesel fuel demulsibility.This method is summarized by ASTM as follows ... 

There was some indication that the presence of nontoxic oil in the emulsion caused a tendency toward selectivity. For example, a 10% emulsion of either methylnaphthalene or dimethylnaphthalene killed the greenhouse test plants with no selectivity. The addition of 20% nontoxic oil, however, greatly reduced the carrot injury without an apparent reduction in toxicity to the other species. Tests were conducted with water emulsions of highly phytotoxic naphthas which contained 75 to 85% aromatics and had boiling ranges of to 550 F. Excellent selectivity was obtained in some tests, but in other tests the emulsion gave severe injury to carrots. The results with emulsions of high aromatic naphthas were inconclusive. 

Another new adjuvant used in a flu vaccine in Europe is called as MF59, which is a submicron oil in water emulsion containing squalene as the oil phase. This adjuvant emulsion is safe and nontoxic for use in humans and has been tested in several million subjects (13-16). The vaccine formulation contains MF59 (FLUAD) , which is a licensed product in Europe and has been shown to be safe and well tolerated in patients over the last seven years. 

Figure D3.4.7 showstypical results obtained from a storage stability test (see Basic Protocol 1) of an oil-in-water emulsion that consists of a 20% (v/v) hexadecane-in-water emulsion stabilized by 2% (w/v) polyoxyethylene-20-sor-...

As shown above, the pulsed field gradient NMR technique was first described by Tanner and Stejskal [1,2]. In addition to their work on unrestricted diffusion they also performed theoretical analyses of restricted diffusion and tested their results on octanol-in-water emulsions stabilized by surfactants. 

Another area of interest is in the emulsification properties of gum acacia. The protein-rich fractions which are amphiphillic in nature are responsible for stabilization of oil-in-water emulsions by gum arabic. Immunoassays developed against these protein-rich fractions can be used to measure emulsification capability. This was tested out (148) using heated and unheated gum samples. The heated samples exhibit poor emulsification properties versus the unheated and ELISA was able to distinguish these two gums, indicating the viability of using IA for testing the emulsification properties of gum acacia. 

In general, emulsion tests range from simple identifications of emulsion presence and volume to detailed component analyses. The term frequently refers simply to the determination of sediments in an emulsion or oil sample. See Basic Sediment and Water. 

Fluhr et al. presented similar results.21 Four different vehicles (water in oil and oil in water emulsion) and two different glycerol concentrations (5 and 10%) were tested. 10% glycerol was more efficient than 5%, independent of the basic formulation. However, the o/w emulsion seemed to be more effective than the w/o formulation.21... 

Tornberg and Ediriweera, 1987). Phase inversion temperature (Shinoda and Saito, 1969) and emulsifying capacity (Swift et al., 1961) have been used to evaluate the effects of low molecular weight and protein emulsifiers, respectively. Unfortunately, it is not possible to measure the size of the large droplets present in unhomogenized water-in-oil emulsions because the droplets coalesce very quickly. The phase inversion temperature is not a relevant test, as it may not be related directly to the stability to inversion at the emulsification temperature. Furthermore, it has been stated (Matsumoto and Sherman, 1970) that water-in-oil emulsions do not exhibit a true phase inversion temperature, unlike oil-in-water emulsions. 

Figures 1 and 4 show the water flood matches to the water-wet and oil-wet lab model curves, respectively. The carbon dioxide flooding runs in the lab model were then matched by computer simulation. In the simulations, as in the lab model, the carbon dioxide slug was followed by waterflooding to an assumed economically limiting water cut of 98%, and the enhanced oil recovery was calculated as the difference between the ultimate total recovery at this point and that of a water flood starting from initial oil saturation and continued until a 98% water cut was reached. Secondary carbon dioxide floods started from the same initial oil saturation, while tertiary carbon dioxide floods started with the condition at the 98% water cut point in the simple water flood. Since the foam or emulsion tests involved a 1 1 ratio of water and carbon dioxide, comparisons are shown only for the case of 1 1 WAG operation vs foam.

Review of the literature resulted in several references relating to the use of emulsions as agents for causing permeability reduction. McAuliffe (2) demonstrated that injection of externally produced oil-in-water emulsions at 24 C effectively reduces the water permeabilities of sandstone cores. These laboratory findings were later substantiated by a field test of emulsion injection followed by waterflooding in the Midway-Sunset Field (3). 

Particle Size. After determining, with bottle tests, which systems easily produced stable oil-in-water emulsions, the droplet size distributions for the oil-in-water emulsions were determined with a Model TA II Coulter Counter. The quantitative results obtained with the Coulter Counter were verified by qualitative observations with an optical microscope. The droplet size distributions for several oil-in-water emulsions are given in Figure 5. A qualitative correlation between droplet size and emulsion stability was observed. The smaller the median droplet size, the more stable was the emulsion. The pore size distribution for a 300-md Berea sandstone core is given for comparison. 

Injecting 0.5 PV of 2.5% Kern River oil-in-water emulsion into a sandpack made from Kern River sand reduced the permeability from 1624 to 397 md, a reduction of 76%. This is a significant result since injection of 0.5 pore volume of a steam-swept zone is economically viable should a field test be performed. An additional 0.5 PV of the emulsion was injected, lowering the permeability to 226 md. The stability of the block under steamflooding conditions was tested by injecting saturated steam at 150 C. After steam injection, the permeability was 406 md—still a 75% reduction in effective permeability (see Table VI). 

In the third test, the core was not saturated with oil before waterflooding, and the oil saturation was only 34%, resulting in higher initial permeability. Under this condition, the reduction in effective permeability increased to 43%. In all three tests, oil-in-water emulsions were produced from the core which had droplet size distributions appropriate to cause blockage of pore throats. These three tests illustrate that it is difficult to simulate in a one-dimensional model the conditions which exist in an actual reservoir after a steamflood, but that it is possible to create "emulsion blocks" in situ under appropriate conditions. 

The injection of emulsifier caustic into the Kern River sandpack (test 4) caused a significant permeability reduction, but not until injection of 1 PV of water. The stability of this "block" to steam was not tested. The photograph of the sandpack in Figure 11 reveals that brown, oil-in-water emulsions were formed in situ during the experiment. 

Two different approaches have been taken toward waterborne alkoxysiloxane and alkoxysilane waterproofing materials. The recent patent literature contains many references to emulsions of alkoxysilanes and silane—resin mixtures (87) that claim stabihty to hydrolysis until the emulsions are applied and allowed to dry on the masonry, at which point hydrolysis and condensation are underway. Alkoxysilane stabihty within the emulsion is obtained through judicious choice of emulsifiers and the use of buffering agents to minimize pH drift. Excellent performance in static water holdout tests may be obtained with these systems, although initial water beading by the cured coatings can be somewhat compromised by the presence of surfactant. 

Several techniques determine whether the continuous phase is oil or water. The simplest is the dilution method, in which a drop or two of the emulsion is added to water. If it is an oil-in-water emulsion it will spread and disperse. If it is water-in-oil it will remain as a drop 18). The dilution test can be effective, but care must be taken that sampling the emulsion does not itself determine the continuous phase. For instance, drawing a water-in-oil emulsion up through the capillary of a dropper can cause the emulsion to... 

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