Water-in-oil (W/O) emulsions consist of water droplets dispersed in continuous oil phase. They are encountered at various stages of oil production. The oil produced from an oil-well usually carries a significant amount of water in the form of droplets. In enhanced oil recovery techniques involving the injection of polymer solution, the aqueous phase of the water-in-oil emulsions produced from the oil well consists of polymeric additive. A good understanding of the flow behavior of emulsions in pipelines is essential for the design and operation of oil production-gathering facilities and emulsion pipelines. A number of studies have been reported on simultaneous flow of oil and water in pipelines. However, the studies reported in the literature are mainly focused on either oil-water flow patterns and separated flows (annular and stratified flow of oil and water phases) or oil-in-water (O/W) emulsion flows. The pipeline flow of water-in-oil (W/O) emulsions has received less attention. Also, little work has been carried out on the effect of additives such as polymer. In this study, new experimental results are presented on the pipeline flow behavior of water-in-oil (W/O) emulsions, with and without the presence of polymeric additive in the aqueous phase. The emulsions were prepared from three different oils, namely EDM-244, EDM-Monarch, and Shell Pella of different viscosities (2.5 mPa.s for EDM-244, 6 mPa.s for EDM-Monarch, and 5.4 mPa.s for Shell Pella, at 25 0C). The water-in-oil emulsions prepared from EDM-244 and EDM-Monarch (without any polymeric additive in the dispersed aqueous phase) exhibited drag reduction behavior in turbulent flow. The turbulent friction factor data of the emulsions fell well below the standard Blasius equation for smooth pipes. The water-in-oil emulsions prepared from EDM-244 exhibited stronger drag reduction as compared with the EDM-Monarch emulsions. The Shell Pella emulsions (w/o type) did not exhibit any drag reduction in turbulent flow; the friction factor data followed the Blasius equation. The Shell Pella emulsions were more stable than the EDM-244 and EDM-Monarch emulsions. When left unstirred, the EDM-244 and EDM-Monarch emulsions quickly coalesced into separate oil and water phases whereas the Shell Pella emulsions took significantly longer time to separate into oil and water phases. The Shell Pella oil emulsions were also milkier than the EDM emulsions. The addition of polymer to the dispersed aqueous phase of water-in-oil emulsions had a significant effect on the turbulent drag reduction behavior. Emulsions were less drag reducing when polymer was present in the aqueous droplets. The effect of surfactant on the pipeline flow behavior of water/oil emulsions was also investigated. The surfactant-stabilized water-in-oil emulsions followed the single phase flow behavior. The presence of surfactant in the emulsions caused the dispersed droplets to become significantly smaller. It is believed that the droplets were smaller than the scale of turbulence when surfactant was present and consequently no drag reduction was observed.

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Thesis (Ph. D.)--Institute of Paper Chemistry, 1960. / Includes bibliographical references (p. 96-101).

For the first time the interfacial properties of nonionic hydrocarbon surfactants at both the air-water and CO₂-water interfaces are investigated in terms of surfactant structure to determine the changes in surfactant efficiency (negative of the logarithm of the surfactant concentration to create a surface pressure of 20 mN/m). At the air-water interface, linear surfactant tails are more efficient due to the higher packing ability of the straight chains in the dense surfactant monolayer. However, at the CO₂-water interface, surfactant adsorption is small and tails can be solvated. Thus, branching which increases both tail solvation and tail hydrophobicity also enlarges the hard disk area of the surfactant to ultimately increase the efficiency of the surfactant at the CO₂-water interface. CO₂-in-water concentrated emulsions (foams) are studied over short and long times to evaluate the foam stability as a function of both surfactant structure and foam conditions using in-situ optical microscopy. The surface pressure measured at the CO₂- water interface is correlated with the short time stability of coalescing foams with very small cell sizes (under 0.4 [mu]m in diameter). Long time stability of bubbles to coalescence is shown under a variety of conditions. The rheology of these bulk CO₂-in-water foams under high-pressure conditions are also evaluated through measurements of the pressure drop over a capillary tube. Viscosities in excess of 200 cP are measured, an increase of over 1000 time that of pure CO₂ (0.09 cP at 24 °C and 2000 psia). The viscosity of the C/W foams are found to correlate with bubble size, continuous phase viscosity, shear rate, and interfacial tension. Hydrophobic silica particles adsorbed at the interface are also used to stabilize water-in-CO₂ emulsions as an alternative to surfactant stabilizers. The difficulties of tail solvation associated with many hydrocarbon surfactants in CO₂ can be removed by using particles instead of surfactant. A porous cross-linked shell is formed about the hydrophilic (colloidal and fumed) silica to render the particles CO₂-philic and the crosslinking removes ligand tails from the particle surface. / text

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The interfaces of bubbles and droplets imbue foams and emulsions with extraordinary mechanical and chemical properties. The remarkably large interfacial area of these structures controls their thermodynamics and makes them practical and functional materials. When these interfaces are forced to touch, they can turn a dispersion of one fluid in another into a solid. These solid-like properties are evident in common household products such as shaving foam and mayonnaise, and our ability to control the fluid and solid properties of these materials is essential to their function. / Physics

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Soy whey protein isolate (SWPI) – Fenugreek gum conjugates were developed and their molecular characteristics and emulsifying properties were investigated. SWPI was extracted from soy whey of tofu processing. SWPI exhibited excellent emulsifying properties comparable to soy protein isolate. However, to improve the emulsifying properties of SWPI for some applications, it was conjugated to fenugreek gum. The extent of conjugation was verified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), Fourier transform infrared (FTIR) and High performance size exclusion chromatography (HPSEC). The SDS-PAGE of the conjugates showed polydispersed bands at the top of the separating gel in the conjugates suggesting the formation of high molecular weight products. Refractive index spectrum of HPSEC profiles showed a reduction of protein peak of unconjugated mixture and shifted a peak to higher molecular weight of the conjugates. Ultraviolet spectrum of HPSEC showed an increase of protein peak intensity at polysaccharide region. FTIR spectrum showed an amide band I and II were still observed in the conjugates after the unreacted proteins were removed. 1D NMR spectra showed that fenugreek gum was covalently bound to proteins through interaction between the reducing end of mannose residue and lysine. The protein solubility of SWPI – Fenugreek gum conjugates improved as compared to SWPI and SWPI – Fenugreek gum mixture when assessed in the pH range 3 to 8 at 22oC, especially at isoelectric point of protein (pl). A 1:3 and 1:5 ratio of SWPI – Fenugreek gum gave rise to better emulsion stabilization compared to 1:1 ratio. Particle size analysis revealed that conjugation of SWPI – Fenugreek gum at 60oC for 3 days was enough to produce relatively small droplet sizes in oil-in-water emulsions. SWPI – Unhydrolyzed fenugreek gum conjugates exhibited better emulsifying properties compared to SWPI – Partially hydrolyzed fenugreek gum conjugates. The conjugates improved emulsifying properties of SWPI, particularly around the pl of protein. The emulsifying properties were greatly increased by heating the conjugates before emulsification. The conjugates also improved emulsion stability at high salt concentration compared to SWPI. In summary, incorporation of SWPI into fenugreek gum improved emulsifying properties of SWPI near the pl of protein and at high salt concentration. / No / No

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