Droplet transport and coalescence kinetics in emulsions subjected to acoustic fields

Pangu, Gautam D.; Feke, Donald L.

doi:10.1016/j.ultras.2007.03.004

Cited by 45 publications

(28 citation statements)

References 16 publications

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“…Pangu and Feke [7] classify the forces acting on droplets into interdroplet forces and field forces. For the desalting of oil, the interdroplet forces are represented by attraction forces and natural repulsion between the water droplets and by the attraction force generated by the application of an electric field.…”

Section: The Crude Oil Desalting Processmentioning

confidence: 99%

“…Pangu and Feke [7] provide an equation for the calculation of the attraction energy generated by van der Waals forces. In both cases, the value of the energy of attraction or repulsion, which is the result of the integration of the force over the distance in which it is applied, is only not negligible in relation to the value of the attraction energy generated by the application of the electric field, when the distance between the droplets is between 1 and 10 nm, which will be considered in this work.…”

Section: The Crude Oil Desalting Processmentioning

confidence: 99%

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Coalescence of Water Droplets in Crude Oil Emulsions: Analytical Solution

2010

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In petroleum refineries, water is used in desalting units to remove the salt contained in crude oil. Typically, 7 % of the volume of hot crude oil is water, forming a water-and-oil emulsion. The emulsion flows between two electrodes and is subjected to an electric field. The electrical forces promote the coalescence of small droplets of water dispersed in crude oil, and these form bigger droplets. This paper calculates the forces acting on the droplets, highlighting particularly the mechanisms proposed for droplet-droplet coalescence under the influence of an applied electric field. Moreover, a model is developed in order to calculate the displacement speed of the droplets and the time between droplet collisions. Thus, it is possible to simulate and optimize the process by changing the operational variables (temperature, electrical field, and water quantity). The main advantage of this study is to show that it is feasible to increase the volume of water recycled in desalting processes, thus reducing the use of freshwater and the generation of liquid effluents in refineries.

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Section: The Crude Oil Desalting Processmentioning

confidence: 99%

Section: The Crude Oil Desalting Processmentioning

confidence: 99%

Coalescence of Water Droplets in Crude Oil Emulsions: Analytical Solution

2010

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“…The relative trajectory equations for a pair of droplets were derived previously (Pangu and Feke, 2007). For an isothermal emulsion of spherical droplets in an immiscible fluid, with no bulk flows or surfactants, and interacting under the influence of a one-dimensional standing ultrasonic wave field, the relative velocity of droplets,V 12 , (presented in the form developed by Batchelor (1982)) is given by:…”

Section: Relative Trajectory Equations For Droplet Motionmentioning

confidence: 99%

“…The centerpiece of the chamber is a Plexiglas frame that forms the cavity in which the acoustic field is propagated. The design of the chamber and the electronics used to activate acoustic field inside the chamber are described in detail in Pangu and Feke (2007). An aqueous emulsion of vegetable oil was prepared by vigorous stirring of oil and water mixture followed by its sonication for 5 min; this was subsequently diluted with filtered (to 1 m) deionized water.…”

Section: Experimental Set-up and Proceduresmentioning

confidence: 99%

“…In our recent publication (Pangu and Feke, 2007), we reported on the development of a mathematical model, valid on the length scale of droplets, which enables a fundamental understanding of the relevant physical and chemical phenomena that underlie the process of oil retention by bulk coalescence. The model comprises pertinent body forces and interdroplet effects to predict the relative trajectory of a pair of droplets.…”

Section: Introductionmentioning

confidence: 99%

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Kinetics of ultrasonically induced coalescence within oil/water emulsions: Modeling and experimental studies

Pangu

Feke

2009

Chemical Engineering Science

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Development of multilayered cell‐hydrogel composites using an acoustic focusing technique

Mazzoccoli

Feke

Baskaran

et al. 2009

Biotechnology Progress

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Multi-layered composites composed of mammalian cells arranged in a hydrogel have been prepared using an acoustic focusing technique. Acoustic focusing is a simple, non-chemical technique that allows for the fast arrangement of cells in matrices where the control of cell geometry is beneficial. Breast cancer cells (MDA-MB231), were dispersed in a 30 wt % solution of poly(ethylene glycol) diacrylate (PEGDA) of molecular weight 400 at a density of 5 × 10 6 cells per ml of PEGDA solution. An ultrasonic field was used to organize the cells into multiple layers prior to polymerization of PEGDA. Disk-shaped hydrogel composites, typically 1 cm in diameter and 2 mm thick were prepared based on a PEGDA solution volume of 130 uL. At an acoustic frequency of 2.32 MHz, composites were fabricated, where concentric rings/layers of cells were interspersed with cell-free hydrogel. The cells were located in annuli approximately 80 μm thick and about 300 μm apart. The structure and viability of the cells within these constructs were studied using a fluorescent LIVE/DEAD assay. The viability of the cells was on the order of 50%. Cell death was primarily attributed to exposure of cells to the PEGDA solution prior to polymerization, rather than adverse effects of polymerization or the sound field itself.

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Droplet transport and coalescence kinetics in emulsions subjected to acoustic fields

Cited by 45 publications

References 16 publications

Coalescence of Water Droplets in Crude Oil Emulsions: Analytical Solution

Coalescence of Water Droplets in Crude Oil Emulsions: Analytical Solution

Kinetics of ultrasonically induced coalescence within oil/water emulsions: Modeling and experimental studies

Development of multilayered cell‐hydrogel composites using an acoustic focusing technique

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