Emulsion Breakdown Research Articles

Microwave Heating of an Emulsion Drop

The results of numerical modeling of the microwave heating of a water-in-oil emulsion drop in a gravity field with consideration of the empirical temperature dependence of the viscosity of the liquid surrounding the drop are presented. The system of thermal convection equations is considered in the Boussinesq approximation. The solution is obtained by the control volume method with the SIMPLE algorithm and by the VOF method. It is established that the emerging convective structures result in nonuniform heating of the drop predominantly near the surface, which can lead to a local rupture of the armor envelope and the formation of fine-dispersed phase. It is shown that there is an optimal range of power of microwave field in which an intensive deposition of water drops occurs, which leads to water-oil emulsion breakdown.

Physical compatibility of MCT/LCT propofol emulsions with crystalloids during simulated Y-site administration

ObjectiveIn intensive care units numerous drugs have to be infused simultaneously, resulting inline incompatibility. Propofol is formulated as a lipid emulsion and it is well known that electrolytes can affect...

Extraction induced by emulsion breaking: A model study on metal extraction from mineral oil

This work reports, for the first time, a detailed investigation on the effect of experimental parameters that affect the extraction induced by emulsion breaking. In this study, we evaluated the influence of the type (Triton X-100, Triton X-114, Tween 20 and sodium dodecylsulfate) and concentration of the surfactant employed as emulsifying agent, as well as the type (HCl or HNO3) and concentration of the mineral acid employed for the extraction of As, Cr, Cu, Mn, Pb and V of spiked mineral oil. The metals were added to the mineral oil in the form of organometallic compounds. In all cases, the emulsion breakdown was induced by heating at 90 °C in a thermostatic bath and the extracts were analyzed by graphite furnace atomic absorption spectrometry (GF AAS). The time required to achieve emulsion breakdown and the extraction efficiency were taken as responses for evaluation. The obtained results showed that the extraction of metals was more efficient when Triton X-100 or Triton X-114 were employed in the preparation of the emulsions. Both HCl and HNO3 provided quantitative extraction of the analytes when combined with these surfactants, except in the case of As, in which the extraction efficiencies were in the range of 22–60%. However, the emulsions prepared with HCl needed longer times to be broken down. Samples of mineral oils (new and used) from vacuum pumps were analyzed and the results compared with those obtained with the model sample. Only As and V could not be determined in the real samples.

Salmon Protamine Decreases Serum and Liver Lipid Contents by Inhibiting Lipid Absorption in an In Vitro Gastrointestinal Digestion Model and in Rats.

Protamine has been used as an antiheparin drug and a natural preservative in various food products. However, limited studies have evaluated the physicochemical and functional properties of protamine. Hence, we assessed the mechanisms underlying the inhibition of lipid absorption following salmon protamine intake in in vitro and in vivo studies. In initial experiments, a salmon protamine hydrolyzate (PH) was prepared using in vitro simulated gastrointestinal digestion suppressed pancreatic lipase activity and micellar cholesterol solubility. This PH had higher bile acid-binding capacity and emulsion breakdown activity than casein hydrolyzate and l-arginine. However, the hypolipidemic functions of protamine were dramatically reduced by pancreatin digestion. In further experiments, groups of male Wistar rats were fed an AIN-93G diet containing 5% (wt/wt) salmon protamine or a protamine amino acid mixture. After 4 wk of feeding with experimental diets, reductions in serum and liver triacylglycerol (TAG) and cholesterol contents were observed in the presence of protamine, reflecting inhibition of TAG, cholesterol, and bile acid absorption. These data suggest that the formation of insoluble PH-bile acid complexes is critical before the bile acid-binding capacity is reduced. Therefore, dietary salmon protamine may ameliorate lifestyle-related diseases such as hyperlipidemia and obesity.

Breakdown of Water-Oil Emulsions in an Electric Field

A large amount of water-oil emulsions is formed during the recovery, refinement, transport, and utilization of oil products. On entering the ambient medium, they contaminate surface and ground waters, and alter the composition of the soils. Utilization of the water provides a significant saving of water resources, and reduces the anthropogenic affect of petrochemical entities on the environment. Developments of effective technologies for separation of water-oil emulsions and extraction of oil products from them are therefore critical [1‐5]. Existing mechanical, thermal, and physicochemical methods of breaking down water-oil emulsions are expensive, and do not always ensure the required quality of the breakdown. A promising method of separating water-oil emulsions is their breakdown in an electric field [6‐9]. Parameters affecting separation of water-oil emulsions are: the velocity and regime of the flow of emulsion; its disperse composition; the strength of the electric field; the electrical conductivity, viscosity, and density of the emulsion; the surface tension at the interface between the liquids; the shape and dimensions of the electrodes and effective zone, etc. [10‐12]. To improve the separation efficiency of water-oil emulsions, develop of electric dehydrators (equipment for separation of water-oil emulsions), and refine methods for the design of corresponding production systems, it is necessary to investigate the extent to which hydrodynamic and electrophysical factors influence the efficiency of the electrodehydration process. Investigations (on a laboratory unit, and by methods of computer modeling) of the effect of an electric field on the hydrodynamic parameters of the breakdown of an emulsion were conducted as a function of the strength of the electric field, the shape and dimensions of the electrodes, their arrangement in the effect zone, and the flow velocity of the emulsion. The time required for coalescence of water drops in oil products was selected as the basic criterion of the intensity of the process, since this parameter permits complete evaluation of the processes that take place, and the operating efficiency of the equipment. Composition of experimental unit: glass compartment; system of electrodes; high-voltage transformer; monitoringmeasuring instruments (microammeter, kilovoltmeter) for recording of electric-field parameters; and filming equipment to record the processes that are taking place at a rate of 100 frames/sec [8‐10]. Crude oil, and castor and transformer oils were used as working media. The physicochemical properties of the working media at 0°C are presented in Table 1. Selection of the working media was dictated by the fact that the hydrodynamic

Wetting and deterging effects of a surfactant in the breakdown of water-oil emulsions

The deterging effect and wetting capacity of some widely used commercial surfactants and demulsifiers are examined and studied from the standpoint of the oilfield treatment of crude oil. The deterging effect of surfactants of various structures is shown to be selective in washing off disperse particles of mechanical paraffin, resin, and asphaltene impurities from the surface. New methods are proposed for determining the deterging effect of surfactacts in oil-bearing disperse systems. The mechanism of breakdown of the structure of disperse particles surrounded by a hydrocarbon adsorption layer under the action of detergents is described. The studies identified a number of surfactants that have an intrinsically pronounced deterging effect.

Emulsion graft polymerization of 4-chloromethylstyrene on kenaf fiber by pre-irradiation method

The stability of micelle size in 3% 4-chloromethylstyrene (CMS), 0.3% Tween 20 in water emulsion over time was studied using a static light scattering. It was found that the micelle diameter decreased with storage time and temperature. The influence of micelle size over time was then explored by adjusting the ratio of CMS to Tween 20 (10:1, 10:2, 10:4) at CMS concentration of 0.2–5.0%. It was found that the increase in average micelle diameter resulted in a decreased in the stability of CMS emulsion. Graft polymerization of CMS on kenaf fiber was carried out in emulsion with 350nm micelle at various CMS concentrations at a dose of 150kGy. It was found that the degree of grafting (Dg) was strongly dependent on the monomer concentration and time. However, the increase in micelles diameter from 250nm to 500nm resulted in the increased in Dg from 3% to 153%. This extraordinary result led us to investigate the micelle size distributions of CMS emulsion during graft polymerization. It was found that the diameter of micelle decreased rapidly to 100nm within 2h. It was discovered from digital photomicrography the existence of multiple emulsions in the CMS emulsion. It was proposed that the enhancement of grafting yield is governed by emulsion breakdown mechanisms through radical effect during radiation induced graft polymerization.

CUTTING FLUID OILY WASTEWATER: BREAKDOWN AND REUSE OF THE RECOVERED OIL PHASE

The aim of this work is to evaluate the use of electrolytes in the breakdown of waste by cutting fluid emulsions, reusing the recovered oil phase to develop new cutting fluids. Four cutting fluids were used to obtain oily emulsions: two commercial, OP38 (Lubrax) and Dromus (Shell), and two developed formulations, CF1 and CF2. The emulsions were prepared by using 5 to 30 wt.% cutting fluid in water. NaCl and CaCl2 solutions were used to promote the destabilization of emulsions, taking into account the percentage of oil recovered as a function of time, observing the influence of type and concentration of electrolyte, temperature, and emulsion droplet size. The aqueous effluent obtained after oil phase removal was characterized by turbidity, oil and grease content, pH, and presence of anions and cations. The use of CaCl2 (2 wt.%), at 25°C, provided the best results in emulsion breakdown and the best quality of the water phase. All the parameters evaluated in these water phases were in accordance with the specifications established by Brazilian legislation that regulates the disposal of wastewater in surface waters. The physicochemical properties of the recovered oil phases were compared with the ones of the mineral oil NH-20 used to obtain CF1 and CF2. It was verified an increase in total acid number, viscosity and corrosiveness to copper. Additives were added to the recovered oil phases to obtain new cutting fluids. The physicochemical properties of these new cutting fluids were close to the ones of the initial ones, except for the viscosity values which increased.

Study of Interfacial Interactions between Bitumen and Various Aggregates Used in Road Construction

Our objectives were first to develop new physico-chemical methods to characterise the aggregate, the bitumen, and the bitumen emulsion surfaces, then to compare the properties of the new sustainable emulsifiers with those currently used in the road industry, and finally to explain the role of the bitumen/aggregate interactions in the bitumen emulsion breakdown. It was possible by using a Drop Shape Analysis System to determine the surface tension of complex liquids such as bitumen, surfactant containing aqueous phase, and bitumen emulsions. The interfacial phenomena between a bitumen emulsion and an aggregate are driven by the polar and dispersion interactions. The polar interactions play a major role in the emulsion adhesion to the aggregate and also in the emulsion breakdown.

Sugar Crystallization and Glass Transition as Destabilizing Factors of Protein-Stabilized Emulsions

Temperature cycling across the glass transition of the aqueous phase of oil-in-water emulsions stabilized by whey protein isolate was considered as a possible factor affecting stability. Emulsions were formulated with an aqueous phase containing 80% (w/w) fructose, fructose:glucose 1:1 or glucose, in order to prepare a glass forming aqueous phase with sugar concentration corresponding to that of the unfrozen phase of the maximally freeze-concentrated solutions. This allowed thermal cycling across the glass transition in the absence of the formation of ice crystals. Emulsion stability was studied using differential scanning calorimetry, dynamic light scattering and by visual analysis of the morphology of the systems. Emulsified systems undergoing glass transition cycles of the aqueous phase did not show destabilization of the dispersed (crystallized) lipid phase. Sugar crystallization in the aqueous phase, which occurred when glucose systems were stored above the Tg, led to emulsion breakdown. In this study, the formation of a glassy structure in the continuous aqueous phase preserved the interfacial structure of WPI, thus protecting the dispersed lipid phase from destabilization. On the contrary, glucose crystallization caused disruption of the interfacial membrane structure and loss of integrity of the interface which resulted in extensive lipid phase destabilization.

Emulsion stabilization by non-ionic surfactants: experiment and theory.

The stability of a dispersion is frequently denoted by a rate constant which is a quantitative measure of the time required for the initial concentration of particles to be reduced to some critical value. The flocculation of hydrophobic sols has been treated in a kinetic study by Smoluchowski (1916, 1917) and a second-order reaction process was found to hold. The kinetics of coalescence of emulsion globules has been studied by van den Tempe1 (1953), who reported that coalescence is a first-order reaction process which occurs only between adjacent drops in an aggregate and which is independent of the number of droplets in the aggregate. An emulsion cannot be thermodynamically stable, but it can display a high degree of permanence in the kinetic sense. Therefore, the factors determining the kinetics of degradation of emulsion systems are of great importance. The first elaborate study of the kinetics of emulsion breakdown was made by King & Mukherjee (1939) on emulsions of olive oil and kerosene in aqueous solutions of soaps. They surmised that emulsion instability was due to the preponderance of a large interfacial area of the disperse phase and decided that a reasonable representation of the process of coalescence would be a measure of the decrease with time in the specific interfacial area S of emulsified oil.

Treatment of Steel Rolling Oily Wastewater: Performance of a CTAB Modified Resin Fixed Column

The effect of operating conditions on the performance of a CTAB modified resin column used for the treatment of steel rolling oily wastewater was investigated. The influence of flow rate, influent oil concentration, fixed column height and influent pH was studied. Experimental results showed that several processes were involved in oil removal from rolling oily wastewater, i.e. emulsion breakdown, coalescence and adsorption. More than 95% of oil content in the influent stream was removed by the modified resin column and it increased by 15% compared with the unmodified resin column.

Effect of fatty and resin acids on properties of the surface of kraft lignin

The effect of oleic and abietic acids on the properties of the surface of alkali lignins and the capability of lignins to stabilize water-oil emulsions was examined with kraft spruce and birch lignins as examples. The kinetics of the breakdown of oleic acid-water and abietic acid-water emulsions stabilized by kraft lignins was studied.

Influence of Polymers on the Emulsified Hydrocarbon Liquid and on the Surfactant Stabilized Toluene/Perfluoro-octane Emulsions

Rheological properties of low and high molecular polymers in toluene were studied by measuring the viscosity and the density as a function of mass concentration and temperature. The linear extrapolation of experimental data based on Huggins, Kraemer, Martin, and Schulz-Blaschke equations was used to find the intrinsic viscosity at infinite dilution. The intrinsic viscosity and the interaction constant show extremes within the investigated temperature scale. The power index in Mark-Houwink equation indicate that the high molecular polymers are extended and the low molecular ones more compact. The high molecular polymers stabilize toluene-perfluoro-octane emulsions. The emulsion breakdown and phase separation followed first order kinetics.

Mannans as stabilizers of oil-in-water beverage emulsions

The stabilizing effect of spruce galactoglucomannan (GGM) on a model beverage emulsion system was studied and compared to that of guar gum and locust bean gum galactomannans, konjac glucomannan, and corn arabinoxylan. In addition, guar gum was enzymatically modified in order to examine the effect of the degree of polymerization and the degree of substitution of galactomannans on emulsion stability. Use of GGM increased the turbidity of emulsions both immediately after preparation and after storage of up to 14 days at room temperature. GGM emulsions had higher turbidity than the emulsions containing other mannans. The initial turbidity increased with increasing GGM content, but after 14 days storage at room temperature, the turbidity was the highest for GGM/oil ratio of 0.10:1 when ethanol-precipitated GGM was used. Increasing the storage temperature to +45 °C led to rapid emulsion breakdown, but a decrease in storage temperature increased emulsion stability after 14 days. Confocal microscopy showed that the average particle size in the bottom part of GGM emulsions stored for 14 days was smaller than 1 μm. A low degree of polymerization and a high degree of substitution of the modified galactomannans were associated with a decrease in emulsion turbidity.

Stabilization of the oleic acid-water emulsion with various kraft lignins

The influence of the initial wood species and polymolecular characteristics on the characteristics of the surface of solid-phase lignin was estimated, and the correlation of these parameters with the ability of kraft lignins to stabilize the oleic acid-water emulsion was examined. The kinetics of breakdown of emulsions stabilized with kraft lignin was studied.

Destabilization‐Enhanced Centrifugation of Metalworking Oil‐in‐Water Emulsions: Effect of Demulsifying Agents

AbstractThe effect of a commercial flocculant (Alpacon® WS009) and two coagulant salts (CaCl2 and AlCl3) on the stability of metalworking oil‐in‐water (O/W) emulsions was examined. Two O/W emulsions were tested: a fresh emulsion, prepared in the laboratory from a commercial concentrate, and a waste metalworking emulsion, provided by a local waste management company, with initial oil concentrations of 32900 and 16900 mg/L, respectively. The emulsion stability was studied at different demulsifier concentrations, temperatures and pH through centrifugation tests, zeta potential and multiple light scattering measurements. Emulsion breakdown is explained by electrostatic repulsion of oil droplets and steric interactions. The former was observed for the laboratory emulsion, while the latter was observed for the waste emulsion. Aluminum chloride was the only effective agent for demulsifying both emulsions.

Examination of the Interaction of Chitosan and Oil-in-Water Emulsions Under Conditions Simulating the Digestive System Using Confocal Microscopy

ABSTRACT Chitosan is a cationic biopolymer that has been used extensively in dietary supplements to reduce fat absorption in the fight against obesity. The mechanism of fat binding of chitosan is still not fully understood and has been the subject of controversy. This study was designed to improve the understanding of the underlying mechanism by investigating the interaction of chitosan with oil-in-water emulsion droplets. Our results indicated that (0.1% w/w) chitosan adsorbed to a 20% w/w phosphatidylcholine-stabilized anionic primary emulsion to form a secondary cationic emulsion by electrostatic attraction forces under conditions resembling the stomach (pH 2). Bile salts (6 mM) were added to simulate secretion in the small intestine and pH increase. Bile salts adsorbed to the chitosan secondary emulsion, which resulted in aggregation of oil droplets followed by coalescence due to close packing of droplets. Increased viscosity (267–2531 cp) and increased degree of deacetylation (40–92% DDA) of chitosan enhanced emulsion breakdown. Increasing the pH to 7.5 without addition of bile salts yielded little aggregation. Pronounced aggregation is thought to decrease the accessibility of lipase to the oil resulting in lower bioavailability and reduced caloric intake. Understanding how chitosan interacts with oil droplets in the digestive tract is vital to developing a comprehensive model of the influence of chitosan on the bioavailability of dietary lipids. The information gained in this study may be useful for the interpretation and experimental design of animal and human feeding studies and for the rational design of chitosan-based functional foods for fat reduction.

Regarding the effect that different twin-tailed surfactant have on a solid stabilized petroleum emulsion

An industrial petroleum emulsion stabilized by colloidal silica particles was treated with four different twin-tailed surfactants: sodium bis-2-(ethylhexyl) sulfosuccinate (AOT), didodecylammonium bromide (DDAB), calcium oleate (Ca(OL)2), and dioctadecyldimethylammonium bromide (DODAB). Fourier transform infrared (FT-IR) spectroscopy, optical microscopy, centrifuge test, and conductivity measurement were employed to determine the effect of the amphiphile molecules on the crude oil emulsion. AOT and DDAB produce emulsion breakdown, while Ca(OL)2 does not alter the emulsion stability and DODAB produces an extra stabilization of it. The AOT adsorption at the oil–water droplet interface is a spontaneous process (ΔHads < 0), which promoted the emulsion breakdown through an inter-droplet interaction mechanism. DDAB needs extra energy (via centrifugation) to destabilize the emulsion. Ca(OL)2 dissolves in oil phase and remains there without altering the emulsion strength, while DODAB increases the emulsion stability.

Heavy Oil and Bitumen Dehydration—A Comparison Between Disc-Stack Centrifuges and Conventional Separation Technology

Summary Recent technological advances are making the exploitation of heavy crude oil reserves increasingly profitable. This paper compares nozzle-type disc-stack centrifuges to conventional separation technology for dehydration of heavy oil and bitumen. The nature and composition of heavy oil leads to a number of undesirable properties, such as its tendency to form stable emulsions in the presence of asphaltenes, particles, and other emulsifiers occurring naturally in the oil. This, combined with a high viscosity and a relatively high solids content, makes dehydration a challenging task that introduces new concerns when compared to dehydrating light crude oil. As the density of the heavy oil increases and approaches that of water, conventional static and gravity-based separation systems become unacceptably large and require excessive heating and chemical addition to produce pipeline-specification oil. Hence, the disc-stack centrifuge is proposed as a compact and efficient solution, enabling breakdown of stable emulsions and removal of dispersed water droplets and solid contaminants from heavy and viscous crudes in both onshore and offshore installations.