Phase Inversion Point Research Articles

Synergistic Effect of Asphaltene, Resin, and Wax Improving the Emulsification and Interfacial Properties of a High-Phase-Inversion Thin Oil.

Nowadays, high-phase-inversion in situ emulsification technology has shown great potential in enhancing oil recovery from high-water-cut thin-oil reservoirs. However, emulsification characteristics, interfacial properties, and the mechanism of high phase inversion have not been systematically described. In this study, an emulsification experiment was conducted to investigate the effects of shear time, shear rate, and temperature on the phase inversion of thin oil. Furthermore, the influence of resin and wax on the dispersion of asphaltene was studied through microscopic morphology analysis. Interfacial tension measurement and interfacial viscoelasticity analysis were carried out to determine the interaction characteristics of asphaltene, resin, and wax at the interface. The results showed that, at 50 °C, the phase-inversion point of thin oil reached as high as 75%, and even at 60 °C, it remained at 70%. The shear time and shear rate did not affect the phase-inversion point of thin oil, while an increase in temperature led to a decrease in the phase-inversion point. Moreover, compared to the 20% phase-inversion point of base oil, the phase-inversion point increased with different proportions of asphaltene, resin, and wax. Particularly, at the ratio of asphaltene/resin/wax = 1:5:9, the phase-inversion point reached as high as 80%, indicating the optimal state. In this proportion, asphaltene aggregates exhibited the smallest and most uniform size, best dispersion, lower interfacial tension, and higher interfacial modulus. These findings provide reference and guidance for further enhancing oil recovery in medium-to-high-water-cut thin-oil reservoirs.

Identification of the Catastrophic Phase Inversion Point of Water-in-Oil Emulsion Using Ultrasonic Measurements

Identification of the Catastrophic Phase Inversion Point of Water-in-Oil Emulsion Using Ultrasonic Measurements

Interfacial behavior and extraction kinetics of phages in a salting-out extraction system of ammonium citrate and ethyl acetate

To fight the increasing emergence and spread of antimicrobial resistance, phages have regained much more interest as the potential substitute in recent years. Separation and purification of phages were developed by salting-out extraction (SOE) with advantages of simpleness, high efficiency, high yield and the easiness to scale-up over the traditional means. In this study, SOE system composed of ammonium citrate and ethyl acetate was used to investigate the partition behavior of phages, phase separation, and extraction kinetics. With the increase of phase volume ratio, the phage phiAB9 was progressively transferred from the bottom phase to the middle phase. Accordingly, the solubility and aggregation of the middle phase increased, and the color got darker. Furthermore, the phase inversion point was kept at phase volume ratio between 1.0 and 1.1, at which the phase separation time was the shortest. The extraction kinetics revealed that the partition behavior could be finished in 10 min without centrifugation. Finally, the SOE system was also viable alternatives for the isolation and purification of phage λ, phiKP1 and phiSM1. The mechanism of SOE process is very important for its application and scale up in phage separation.

Effect of nonionic surfactants on the synergistic interaction between asphaltene and resin: Emulsion phase inversion and stability

Interaction between surface active components in crude oils and nonionic surfactants plays an important role in phase inversion behavior of crude oil emulsion, while the interaction mechanism is not yet fully explored. Herein, the effects of nonionic surfactants on the synergistic interaction between asphaltene and resin, emulsion stability, and emulsion phase inversion were investigated. It is shown that the addition of Span 80 and Tween 80 promotes the reduction of phase inversion point of water in oil emulsion stabilized by asphaltene and resin, as well as increases the yield strain value of the emulsion. The addition of Tween 80 to the asphaltene and resin mixture reduces the inversion point from 70 % to 30 %. The decrease of phase inversion point is attributed to the difficulty in the formation of multiple emulsions after adding nonionic surfactants. The addition of nonionic surfactants can affect the hydrogen bonding between asphaltene and resin, thereby improving the emulsion stability. Span 80 coexists with asphaltene and resin at oil-water interface, reducing the Turbiscan Stability Index (TSI) of emulsion by 15 and improving the strength of the oil-water interface membrane. In comparison, Tween 80 with stronger hydrophilic ability dissolves asphaltene and resin into bulk phase, which leads to the oil-water interface occupied by a large amount of Tween 80. Its numerous EO groups result in the strong hydrogen bonding on the oil-water interface membrane, effectively increasing the strength of the oil-water interface membrane and reducing the TSI by 19. This work contributes to a better understanding of the phase inversion of crude oil emulsion and improves crude oil recovery.

A universal route to deciphering the internal mechanism of crude oil self–emulsification

Crude oil emulsions generated during the life period of crude oil from production and separation comprise a fascinating interdisciplinary topic that is being actively studied in both chemical science and engineering. However, a comprehensive understanding of the emulsification mechanism based on a sound chemicophysical foundation for the natural emulsifiers of crude oil remains challenging and is not well established. In this study, we developed a framework that combines crude oil separation, molecular structure characterization and inference, self–assembly of natural emulsifiers at the oil–water interface, and phase behavior of natural emulsifier emulsions to decipher the self–emulsification of crude oil. Our results revealed that crude oil components have independent and synergistic effects on the formation and stabilization of crude oil emulsions. Asphaltene has the highest molecular weight and the strongest interfacial activity compared to other components, significantly contributing to the formation of crude oil emulsions. As the second highest molecular weight crude oil component, resin is the solvent for asphaltene. Aromatic and saturated hydrocarbons adsorbed at the oil–water interface form an interfacial viscoelastic film that mainly stabilizes the crude oil emulsion. The viscosity of crude oil emulsions is mostly affected by asphaltene and resin, while their phase inversion point is primarily determined by aromatic and saturated hydrocarbons. These results provide a universal insight into the internal emulsification mechanism of crude oil. We expect that these findings will also provide theoretical support for taking advantage of crude oil emulsions for the purpose of efficient oil recovery.

Effect of modified montmorillonite particles on generation of in-situ W/O emulsion and oil displacement mechanism in enhanced heavy oil recovery

Water-in-oil (W/O) emulsions can enhance the sweep efficiency and control the mobility ratio of oil and water simultaneously in heavy oil development. However, the W/O emulsions formed by heavy oils and injected fluids are prone to be with low phase inversion point and low maximum internal phase volume, which leads to serious tonguing and fingering especially in heterogeneous reservoirs. The authors thus proposed a new method of stabilizing W/O emulsions with modified montmorillonite particles (MMPs) to increase the phase inversion point as well as the internal phase volume to enable economically viable recovery of heavy oils. This paper evaluated the emulsions injected with different types of MMPs in terms of stability, maximum internal phase volume, and rheology. The optimal contact angle and particle concentration for modification were 105° and 3000 ppm, and under such conditions, the maximum internal phase volume fraction of the emulsions was increased to 85% and the viscosity by 40 times. In addition, the selected MMPs were then injected into multiple homogeneous cores of different permeabilities to verify the injectability and the viability to form W/O emulsions via pressure curves and NMR two-dimensional spectrum. The results showed that the modified particles can be injected into cores with permeability above 200 mD, but only in cores with permeability above 500 mD can a significant W/O emulsion be observed. Finally, three sets of heterogeneous core flooding tests were conducted in an online NMR system to determine the reasonable timing for injection of the MMPs and to verify its ability to enhance sweep efficiency by monitoring variations in NMR imaging, oil recovery, water cut, and pressure. Our work provides useful insights into the enhancement of sweep efficiency in heterogeneous heavy oil reservoirs by particle-stabilized W/O emulsions.

Influence of processing conditions on the evolution of morphology in PVDF/PS and PP/PS polymer blends: Examining the processing‐phase inversion mechanism

AbstractUnderstanding morphological changes in polymer blends in the initial melting region of an extruder is crucial for optimizing the polymer mixing process. In blends with a large difference in their softening temperatures, a processing‐phase inversion transition occurs when a larger volume‐fraction of the higher melting component is present. The morphological changes in 80/20 PVDF/PS blends were examined (where PVDF forms the major phase) in an internal mixer under different processing conditions, such as preset temperature program, fill volume and rotor speed. We studied the torque behavior, energy consumption during mixing and phase inversion point for both 80/20 PVDF/PS and 80/20 PP/PS blends. PP needed 2.4 times higher mechanical energy to be deformed and to achieve a similar phase inverted state, compared to PVDF. To examine the effect of the minor phase properties, two 80/20 PVDF/minor ph.ase systems were examined: (i) a low‐melting viscous EVA (ethylene vinyl acetate copolymer), and (ii) a low viscosity PCL (polycaprolactone). Using a range of techniques, such as torque monitoring, optical microscopy, SEM etc., it is established that the nature of the minor phase (amorphous vs. semicrystalline), minor phase melt viscosity and the exact processing parameters influence the point at which the phase inversion occurs.

Predicting the emulsion phase inversion point during self-emulsification using an improved free energy model and determining the model applicability

In-situ emulsification has recently shown promise for increasing oil production in water flooding reservoirs owing to its easy procedure and polymer and surfactant properties. The phase inversion point (PIP) plays a vital role in emulsification technology. However, the existing free energy models have limited accuracy in the calculation of the PIP, and the models’ areas of applicability are not specified. The free energy model was improved in this study by classifying crude oil to enhance the prediction accuracy and expand the free energy model’s range of calculation. The applicable range of the model was defined by analyzing and comparing the distribution characteristics of interfacial tension (IFT) and PIP. Firstly, the effects of temperature, shear rate, shear time, salinity, and pH on the PIP were discussed. The experimental results showed that, among these external factors, only the temperature could change the PIP. Generally, the PIP decreased with increasing temperature. Second, different parameters a and b were obtained using the differential aggregation characteristics of oil and water.Then, to further analyze and demonstrate the new model’s accuracy, the experimental data of three new oil samples (crude oil D, G, and J) were collected and compared with the results of other models. The results showed that the new model could successfully fit the data; its average absolute error was 4.47%, while that of the previous models was about 40%. The other models were particularly unsuitable for calculating the PIP of heavy oil, but the new model’s inaccuracy was only 1.48%. Finally, the IFT and PIP data were analyzed and compared. The results showed that, for conventional crude oil, the IFT and PIP decreased with the temperature increase. The applicable conditions of the model were also clarified. The model is suitable for crude oil whose IFT decreases with temperature increase. The results of this study can be used in the petroleum industry and other industries dealing with mixed immiscible fluid transport.

Modeling of the Phase Inversion Point of Crude Oil Emulsion by Characterization of Crude Oil Physical Properties.

Accurate prediction of the phase inversion point (PIP) of crude oil emulsion (COE) will give important guiding significance to the mixed transportation technology during the crude oil mining process. The influence of water cut of a system on viscosity characteristics of the COE was studied by emulsification experiments with 16 kinds of crude oils having significant differences in physical properties. The results showed that under the condition of low water cut of a system, the crude oils can emulsify all the water to form stable W/O emulsions with apparent viscosities much higher than those of pure crude oils. When the water cut of a system exceeds a certain critical value, the crude oils have no ability to emulsify all water; instead, they are wrapped by a water phase and form unstable O/W emulsions, and their apparent viscosities decrease sharply compared with those of pure crude oils. The critical water cut of a system corresponding to the abrupt change of apparent viscosity of the COE is the PIP of the COE changing from the type of W/O to O/W. Furthermore, the apparent viscosities of stable W/O emulsions decrease with increasing shear rate and temperature and meanwhile increase dramatically with the increasing water cut of a system. The apparent viscosities of unstable O/W emulsions decrease with increasing shear rate, water cut of a system, and temperature and are far lower than those of pure crude oils. Four typical parameters were chose as the representation to describe the crude oil physical properties (COPPs), that is, the content of saturates, the content of aromatics, the content of surfactants, and the crude oil acid number. On the basis of the quantitative description of COPPs, a prediction model for the PIP of the COE was established. The results of model verification showed that the mean relative deviation of prediction results was 2.9%.

Effect of Fe(III) Species on the Stability of a Water-Model Oil Emulsion with an Anionic Sulfonate Surfactant as an Emulsifier.

The stability of an emulsion has an important effect on enhancing oil recovery. However, the effect of ions with different valences on the stability of the emulsion emulsified by an ionic surfactant is not fully understood. In this study, the effects of Fe(III) species on the stability, microscopic morphology of droplets, interfacial properties, and rheological properties of water-model oil emulsions emulsified by sodium dodecyl benzenesulfonate (SDBS) were explored. The effect of Fe(III) species on the stability of a W/O crude oil emulsion was also explored. The stability experiment results show that the addition of the Fe(III) species impairs the stability of the model oil-in-water (O/W) emulsion, in which the O/W model oil emulsion is inverted to a water-in-model oil (W/O) emulsion at ∼99 ppm. With the increase of Fe(III) species concentration, stable W/O model oil and W/O crude oil emulsions are obtained. The rheological results indicated that the existence of the Fe(III) species has a remarkable effect on the viscosity and viscoelastic behaviors of the water-model oil emulsion. The calculation results based on Derjaguin–Landau–Verwey–Overbeek (DLVO) theory are in accord with the stability experiment results. Furthermore, the addition of EO groups makes the phase inversion point appear at a higher Fe(III) species concentration, forming a more stable W/O model oil emulsion and a more unstable O/W model oil emulsion. The experimental results are helpful to comprehensively understand the effect of Fe(III) species on the stability of an emulsion emulsified by an anionic sulfonate surfactant, which can help to enhance the oil recovery.

Microflow visualization and electrical signature of tri-n-butyl phosphate/n-dodecane and nitric acid in a centrifugal contactor

Despite the common use of centrifugal contactors in solvent extraction applications, no direct, high-speed visualization of the underlying microflow structure has been published in the open literature. The system in this study is the most prevalent solvent extraction combination used in the nuclear reprocessing industry to extract metal ions from spent nuclear fuel from a nitric acid aqueous solution into an organic mixture of tributylphosphate and dodecane. This study has identified details of the dispersed phase state at all flow conditions of interest, for instance, under common operation conditions the aqueous phase is typically dispersed even when the aqueous flowrate is significantly greater than the organic flowrate. This discovery may have implications when the centrifugal contactor is operated in a stripping mode. Visual observations of the images and simultaneous electrical resistivity measurement of the fluid mixture allowed for the identification of the phase inversion point and hysteresis region captured in a flow regime hysteresis plot. It is shown that it is possible to operate the contactor within the hysteresis region in a stable manner, therefore a choice can be made for the desired dispersed phase. This discovery may have favorable implications for the improved operation of the contactor in either the extracting or stripping modes. This work provides new direct experimental evidence of fluid flow for validating theory, modeling and simulation efforts; there is currently a lack of microflow insight. For instance, existing volume-averaged theories in fluid mechanics do not capture the phase inversion phenomena and/or its hysteresis, which in turn, invalidates predictions of mass transfer.

Experimental investigation of the Electrical Submersible Pump's energy consumption under unstable and stable oil/water emulsions: A catastrophic phase inversion analysis

The presence of water in crude oil exploitation by the Electrical Submersible Pump (ESP) systems may cause several problems in energy consumption and operational instabilities due to emulsion formation. Indigenous surfactants in crude oil also contribute to emulsion stabilization, which can exacerbate these problems. In this paper will be experimentally investigated the influence of the emulsion stability on ESP energy consumption and operational instabilities through an 8-stage ESP operating with unstable and stable emulsions, with and without a demulsifier. The experimental tests were performed for one oil viscosity, a constant total flow rate, and two ESP rotational speeds. Initially, the ESP relative dimensionless power (RDP) was analyzed along with the emulsion system and the droplet size distribution (DSD). An interesting difference regarding the presence of surfactants was observed experimentally in the RDP and phase inversion points. The relationship among the ESP dimensionless power, torque, and electrical current with maximum droplet size allowed to conclude that these parameters can be related to the start of the coalescence process, i. e, able to predict the catastrophic phase inversion (CPI) point.

Experimental study on the ultrasonic echo characteristics of oil–water emulsion

In order to investigate the ultrasonic echo characteristics, a series of oil–water emulsion samples are prepared. The water fraction of the samples is in the range of 0–100%, the stirring speed is set to be 500, 1000, 1500, and 2000r/min, respectively. The ultrasonic measurement was operated in pulse-echo mode. The ultrasonic velocity and attenuation of the samples are measured and analyzed. The results have shown that with the increase of water fraction, the sound velocity tends to increase. The attenuation coefficient is very sensitive to the distribution of the emulsion droplets. Maximum attenuation loss occurred around the phase inversion point, where multiple emulsion is formed. The study has shown a potential to apply the attenuation coefficient for the characterization of emulsion phase inversion.

A nanosheet-based combination emulsifier system for bulk-scale production of emulsions with elongated droplets and long-term stability

In this study, we investigate the emulsion type, droplet morphology and emulsion stability that can be achieved using a novel combination emulsifier system which consists of water-soluble α-zirconium phosphate tetrabutyl ammonium (α-ZrP-TBA) nanosheets as the particulate emulsifier and Span 80 as the oil-soluble emulsifier, with the two emulsifiers present in distinct phases. We find that water-in-oil emulsions were formed for water volume fractions < 0.3, and oil-in-water (O/W) emulsions were formed for water volume fractions > 0.3. This phase inversion point was found to be the same irrespective of whether the emulsifier was only Span 80 or only nanosheet or their combination. Varying the concentrations of either surfactant or the nanosheet did not alter the phase inversion point. The emulsions with the greatest stability against creaming were formed using the combination emulsifier and were found to be the O/W type, that were stable for 3 months. Interestingly, we find that droplets in these stable emulsions were nonspherical, with the aspect ratio of droplets increasing with nanosheet and Span 80 concentration, suggesting a synergistic interaction between the two emulsifiers to create elongated droplets. We perform capillary neck thinning experiments to show that the combination emulsifier system offers unique interfacial properties that are different from either emulsifier alone, suggesting that interfacial jamming could occur to produce elongated droplets. Taken together, our results suggest a novel route to bulk-scale production of O/W emulsions that have long-term emulsion stability with unique droplet morphology.

Experimental study on the key influencing factors of phase inversion and stability of heavy oil emulsion: Asphaltene, resin and petroleum acid

This study investigates the effects of asphaltene, resin and petroleum acid on the phase inversion, stability and oil–water interface characteristics of emulsions. First, different ratios of asphaltene, resin, petroleum acid and formation water were emulsified and the emulsion viscosity was measured to obtain the phase inversion point. Through comparative analysis of phase inversion point data under different conditions, we showed that the synergy of asphaltene and resin was the key to the emulsion phase inversion and the best asphaltene to resin ratio was 1:3. Moreover, the addition of petroleum acid would accelerate the phase inversion. Then, the dynamic interfacial tension of oil and water was measured using the rotating drop method. The synergistic effect of asphaltene and resin would decrease the interfacial tension. However, excessive resin would compete with asphaltene for adsorption, which would increase the interfacial tension. The lowest interfacial value was observed when the mass concentration ratio of asphaltene to resin was. Thus, the addition of petroleum acid significantly reduced the interfacial tension of oil and water. Next, the hanging drop method was employed to measure the interfacial tension of oil and water and the expansion modulus was obtained using the oscillatory drop method. Experimental studies have shown that asphaltene influences the expansion modulus more than resin and the synergistic effect of asphaltene and resin increases the expansion modulus. However, the addition of petroleum acid would decrease the expansion modulus towing to the small molecular weight of petroleum acid. Finally, the emulsion stability was determined using the bottle test method. Experiments showed that the synergistic effect of asphaltene and resin would enhance the emulsion stability. However, the addition of asphaltene played a pivotal role in enhancing the emulsion stability. Further, the addition of petroleum acid would severely destroy the emulsion stability.

Characterizing oil mixture and surfactant mixture via hydrophilic-lipophilic deviation (HLD) principle: An insight in consumer products development

Hydrophilic-lipophilic deviation (HLD) concept describes interaction of surfactant, oil, and water in liquid formulations. Within the framework of HLD, this study investigated the behavior of microemulsion consisting of fragrance/essential oil mixtures and surfactants mixture commonly found in consumer products. Strong non-ideal mixing behavior was seen in oil mixtures of fragrance raw materials. A simple non-ideal relationship was proposed to account for the non-ideality of oil mixture of dissimilar properties. With 95% confidence, the error of the predicted optimum salinity (or phase inversion point) is between 0.70 and 1.68 g/100 mL NaCl in mixtures of complex commercial fragrance and octane. Mixing behavior was also evaluated in a ternary surfactants system consisting of sodium laureth sulfate (SLES), cocamidopropyl betaine (CAPB), and decyl glucoside (APG). Within a reasonable tolerance, the ideal mixing rule can be practically applied for such complex surfactant mixtures. Extension of HLD in mixture systems provides practical benefits in product development.

Substantiating the removal of fat in the technology of obtaining wheat germ and devising technology for making cookies containing it

This paper reports the results of studying the effect of fat removal from wheat germ on its functional-technological properties, as well as its commercial potential, using the technology of butter biscuits as an example. The expediency of large-scale application of fat-free germ has been established for resolving two tasks at the same time: the introduction of the concept of lean manufacturing provided the germ utilization is scientifically justified, that is, creating value without losses. It has been noted that flour confectionery technology has prospects for the introduction of fat-free wheat germ. It has been shown that although wheat germ has a unique chemical composition, it contains much fat, which contributes to the processes of oxidation and rancidity. It is the lack of a scientific base on the influence of the fat removal process on the functional-technological properties of fat-free wheat germ that is a deterrent for its application in the food industry. The paper gives the results from studying the functional-technological properties of wheat germ from which fat was removed with freon-12. The solubility of proteins of fat-free wheat germ depending on the pH has been investigated; it was determined that the conditions for pronounced solubility were created at pH 9. It has been determined that NaCl at a concentration of 1...5 % does not affect the amount of dissolved protein. The results from investigating the surface tension of wheat germ protein solutions and fat-free wheat germ depending on the medium pH are presented. The dependence of values of the surface activity of wheat germ protein solutions on pH has been established. The dependence of the phase inversion point on the concentration of wheat germ and fat-free wheat germ has been investigated. It was determined that the emulsifying ability increases with an increase in the concentration of the suspension to 10 %. A technological scheme for making butter biscuits with the use of fat-free wheat germ has been devised.

Experimental Investigation of Oil-Water Two-Phase Flow in Horizontal, Inclined, and Vertical Large-Diameter Pipes: Determination of Flow Patterns, Holdup, and Pressure Drop

Summary Liquid-liquid phase flow in pipes merits further investigation as a challenging issue that has very rich physics and is faced in everyday applications. It is the main problem challenging the fluid flow mechanism in the oil and gas industry. The pressure gradient of liquid flow and flow pattern are still the topics of numerous research projects. In this paper, the emphasis is on further investigation to research the flow pattern, water holdup (HW), and pressure decrease for vertical, horizontal, and inclined flow directions of oil and water flows. Test section lines of 4.19-in. (106.426 mm) inner diameter (ID) and 5-m horizontal, 5-m inclined, and 5-m vertical test sections were serially connected. The experiments were conducted at 40°C using 2-cp viscosity oil and tap water, and oil density of 850 kg/m3, at the standard conditions. Fifty experiments were executed at 250 kPa at the multiphase flow test facility, with horizontal, upward (0.6° and 4°), downward (−0.6° and −4°) hilly terrain and vertical pipes. The oil and water superficial velocities were changed between 0.03 and 2 m/s. This evidence was obtained using video recordings; the flow patterns were observed, and the selection of each flow pattern was depicted for each condition. For horizontal and inclined flow, new flow patterns were documented (e.g., oil transfer in a line forms at the top of the pipeline, typically at high water rate, and water transfer at the lower part of the pipe at a high oil rate). The data were taken at each flow condition, resulting in new holdup and pressure drop. The results show that the flow rate and the pipe inclination angle have major impacts on the holdup and pressure drop performances. In the vertical flow, a clear peak was demonstrated by experiments after the superficial oil velocity reached a certain value. This peak is known as phase inversion point, where after this peak, the pressure starts declining as the superficial oil velocity increases. Also, slippage has been observed after varying inlet oil flow rates between the two phases. The experiments showed that with minor alteration in the inclination angle, the slippage was significantly changed. This study presented new experimental results (measured mainly at horizontal, inclined, and vertical flow conditions) of HW, flow pattern, and pressure drop. These findings are key evidence of the evolving oil-water and flowline estimate models.

Rheological and flow behavior of water-in-oil Pickering emulsions stabilized with organo-hectorite clay

The rheological and flow behaviors of Pickering emulsions are studied as a function of their water concentration. The studied emulsions are water-in-gasoil inverse emulsions stabilized with organo-hectorite clay. An in-line emulsion preparation was performed and a novel emulsification system was used. The emulsification system was tested and confirmed before performing pipe-flow measurements. A stress-controlled rheometer was used to study the rheological behavior of organoclay stabilized inverse emulsions. It was found that the emulsions exhibited a shear thinning with yield stress non-Newtonian rheological behavior and that the flow curves were well correlated using the Herschel-Bulkley model. Pressure loss and axial velocity measurements were studied to investigate the pipe-flow behavior of the emulsions. Axial velocity of the fluids was measured using an Ultrasonic Pulsed Doppler Velocimeter. It was shown that, up to 50 wt% water mass concentration, an exponential increase of yield stress and viscosity values is noticed, and the phase inversion point is not reached. In the range of the applied flow rates, turbulence took place only in the case of the lowest water cut (0 wt%). The Herschel-Bulkley rheological parameters were used to simulate the pipe-flow behavior of the studied fluids, and showed a satisfactory correlation with the in-line measurements. Furthermore, wall shear stress and velocity profiles were used to study the short-, medium-, and long-term stability of the emulsions.

Identification of Phase Inversion on Sieve Trays

AbstractThe fundamental differences in hydrodynamics of the froth and spray regime account for the ongoing interest in search for the point of phase inversion. This short communication presents a new approach for identification of phase inversion on sieve trays in terms of an image‐based measurement technique. Image analysis of entrained droplets reveals a distinct increase in Sauter mean diameter and droplet frequency during phase inversion. Further measurement methods like pressure drop, gravimetric analysis of entrained liquid, froth height assessment and photographic observation of the flow regime serve as a reference value and complement the discussion. A flow map based on the experimental data comprises each regime and shows a good agreement with phase inversion correlations from literature.