Equilibrium configurations of drops attached to spheres immersed in a uniform laminar flow

Fan, Eddy; Bussmann, Markus; Acosta, Edgar

doi:10.1002/cjce.20414

Cited by 9 publications

(15 citation statements)

References 26 publications

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“…7b reveals that the second transition occurs around a capillary number close to 1. Fan et al conducted Computational fluid dynamic (CFD) simulations on the removal of an oil film from a 100-lm spherical particle fixed in space and subject to a constant flow field under different interfacial tensions and oil loadings [33]. Fan et al found that there was a critical capillary number, close to 1, when the oil film was unstable and detached from the particle.…”

Section: Discussionmentioning

confidence: 99%

“…Although no experiment was carried out beyond particle-based Capillary numbers of 1 (Fig. 8b, d), it is expected that at those conditions the film would not be emulsified, but sheared off the surface, as predicted fluid dynamics calculations [33,36].…”

Section: Discussionmentioning

confidence: 99%

“…3, decreases with increasing toluene addition, meaning that the fluid coating the sand is more susceptible to mechanical instabilities and breakup induced by shear and/or inertial forces. Second, solvent addition increases the volume of the oil phase around the individual particles, thereby enlarging the area and volume where the shear and inertial forces are exerted, thus improving the chances of overcoming the surface tension forces keeping the oil attached to the particle [33]. Regarding the potential impact of toluene on the interfacial activity of bitumen, it is important to keep in mind that the water-toluene interfacial tension is 36 mN/m.…”

Section: Viscosity Of Bitumen-toluene Mixturesmentioning

confidence: 99%

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Capillary Curves for Ex‐situ Washing of Oil‐Coated Particles

Quraishi

Bussmann

Acosta

2015

J Surfact & Detergents

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The oil removal efficiency for the ex situ extraction of bitumen from oil sands, or ex situ washing of oil-contaminated sand and related processes is determined by the balance of forces at the oil/water and solid/fluid interfaces. The objective of this work is to estimate the balance of forces at the interface using dimensionless numbers, and their use in evaluating and engineering ex situ soil washing processes. To this end, bitumen was removed from bitumen-coated sand particles using a twostep process. In the first step, the particles were mixed with a suitable solvent (toluene) used, primarily, to reduce the viscosity of bitumen. The particles were then mixed with water or an aqueous surfactant solution capable of producing low interfacial tensions with the solvent-bitumen mixture. The fraction of oil retained after washing was evaluated as a function of interfacial tension, solvent/bitumen ratio, mixing time, mixing velocity, and particle size. These ex situ washing conditions were normalized using dimensionless film and particle-based Weber and Capillary numbers. The fraction of oil retained by the particles was plotted against these dimensionless numbers to generate capillary curves similar to those used in enhanced oil recovery. These curves reveal the existence of a critical film-based Weber number and a particle-based Capillary number that can be used in the design or evaluation of soil washing processes. The film-based Weber number also explained literature data that associates interfacial tension with the removal of oil from oil-based drill cuttings, as well as field observations on the role that particle size plays on the removal of oil in soil washing operations.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Viscosity Of Bitumen-toluene Mixturesmentioning

confidence: 99%

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Capillary Curves for Ex‐situ Washing of Oil‐Coated Particles

Quraishi

Bussmann

Acosta

2015

J Surfact & Detergents

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“…In summary, there remains a lack of studies on the hydrodynamics of separation from an oil-coated particle. The work presented here complements the research of Fan et al [19] and Smith and Van de Ven [16]. We present an experimental study of the separation of oil from an oil-coated sphere in free fall through an immiscible viscous fluid, and complementary numerical results.…”

Section: Fig 1 An Oil-coated Particle Falling Through An Aqueous Somentioning

confidence: 61%

“…The CFD study of Fan et al [19] is most closely related to the work presented here. A model of an oil-coated particle immersed in an axisymmetric laminar flow was developed.…”

Section: Fig 1 An Oil-coated Particle Falling Through An Aqueous Somentioning

confidence: 63%

The Effect of Viscosity Ratio on the Hydrodynamics of Separation From an Oil-Coated Particle

Mehrabian

Abbaspour

Bussmann

et al. 2014

Volume 1A, Symposia: Advances in Fluids Engineering Education; Turbomachinery Flow Predictions and Optimization; Applications I

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Separating oil from solid particles is of great importance in many industrial processes including the extraction of bitumen from oil sands, and the remediation of oil spills. The usual approach is to separate the oil from the solid by introducing another liquid (e.g. water). Separation is often assisted by fluid mixing, and chemical addition. Yet while oil-water-particle separation has been well studied from a chemical standpoint, little research has taken into account the effect of hydrodynamics on separation. In this work, the separation of oil from a single oil-coated spherical particle falling through an aqueous solution was evaluated as a function of viscosity ratio. Solvents were used to modify the viscosity of the oil. The experiments were recorded using a high-speed camera and post-processed using the MATLAB image-processing toolbox. A CFD model has also been developed to study this phenomenon. The results indicate that when viscous forces are strong enough, the oil film deforms, flows to the back of the sphere, and forms a tail that eventually breaks up into a series of droplets due to a capillary wave instability. When the viscosity ratio is small (i.e. the oil is less viscous than the solution), a thin tail forms quickly, the growth rate of the instability is high, and hence the tail breaks very quickly into smaller droplets. When the viscosity ratio is high (i.e. the oil is more viscous), more time is required for the deformation/separation to initiate, and the tail is thicker and breaks more slowly into larger droplets. It was observed that when the viscosity ratio is close to 1, the rate of separation is increased and maximum separation is achieved.

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Surfactant Technologies for Remediation of Oil Spills

Acosta¹,

Quraishi²

2014

Oil Spill Remediation

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Equilibrium configurations of drops attached to spheres immersed in a uniform laminar flow

Cited by 9 publications

References 26 publications

Capillary Curves for Ex‐situ Washing of Oil‐Coated Particles

Capillary Curves for Ex‐situ Washing of Oil‐Coated Particles

The Effect of Viscosity Ratio on the Hydrodynamics of Separation From an Oil-Coated Particle

Surfactant Technologies for Remediation of Oil Spills

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