Atomic force microscopy (AFM) is frequently used to elucidate complex interactions in emulsion sy... more Atomic force microscopy (AFM) is frequently used to elucidate complex interactions in emulsion systems. However, comparing results obtained with "model" planar surfaces to curved emulsion interfaces often proves unreliable, since droplet curvature can affect adsorption and arrangement of surface-active species, while droplet deformation affects the net interaction force. In the current study, AFM was utilized to study the interactions between a colloidal probe and water droplet. Force magnitude and water droplet deformation were measured in asphaltene and bitumen solutions of different concentrations at various droplet aging times. Interfacial stiffening and an increase in particle-droplet adhesion force were observed upon droplet aging in bitumen solution. As reported in our previous study (Kuznicki, N. P.; Harbottle, D.; Masliyah, J.; Xu, Z. Dynamic Interactions between a Silica Sphere and Deformable Interfaces in Organic Solvents Studied by Atomic Force Microscopy. Langmuir 2016, 32 (38), 9797−9806), a viscoelasticity parameter should be included in the high force Stokes-Reynolds-Young-Laplace (SRYL) equations to account for the interfacial stiffening and non-Laplacian response of the water droplet at longer aging times. However, following the addition of a biodegradable demulsifier, ethyl cellulose (EC), an immediate reduction in both the particle-droplet adhesion force and the rigidity of the water droplet occurred. Following EC addition, the interface reverted back to a Laplacian response and droplet deformation was once again accurately predicted by the classical SRYL model. These changes in both droplet deformation and particle-droplet adhesion, tracked by AFM, imply a rapid asphaltene/bitumen film displacement by EC molecules. The colloidal probe technique provides a convenient way to quantify forces at deformable oil/water interfaces and characterize the in-situ effectiveness of competing surface active species.
Recent studies have successfully measured surface forces using 8 atomic force microscope (AFM) an... more Recent studies have successfully measured surface forces using 8 atomic force microscope (AFM) and modeled surface deformations using the Stokes−Reynolds−Young−Laplace (SRYL) equations for particle−droplet, particle−bubble, droplet−droplet, and bubble−bubble systems in various solutions. The current work focuses on interactions between spherical silica particles and a viscoelastic interface of water droplets in crude oil. The self-assembly of surface active natural polyaromatic molecules (NPAMs) at the oil−water interface has previously been shown to change a viscous dominant oil−water interface to an elastic dominant interface upon aging, due to gradual formation of rigid interfacial networks. AFM was used to measure the interactions between a small silica sphere (D ≈ 8 m) and a deformable water droplet (D ≈ 70 m), which exhibits time-dependent interfacial viscoelasticity in NPAM solutions. Unlike the systems studied previously, the measured deformation shown as a repulsive force over the region of constant compliance could not be modeled adequately by the conventional SRYL equations which are applicable only to purely Laplacian interfaces. As the water droplet ages in NPAM solutions, a rigid "skin" forms at the oil−water interface, with the interface exhibiting increased elasticity. Over a short aging period (up to 15 min in NPAM-in-toluene solution), interfacial deformation is well predicted by the SRYL model. However, upon further exposure to the NPAM solution, droplet deformation is over predicted by the model. Physical properties of this mechanical barrier as a function of interfacial aging were further investigated by measuring interfacial tension, dilatational rheology, and interfacial "crumpling" (non-smooth, non-Laplacian interface) upon droplet volume reduction. By introducing a viscoelasticity parameter to account for interfacial stiffening and using experimentally determined elasticity, we are able to correct this discrepancy and predict droplet deformation under AFM cantilever compression. This parameter appears to be important for modeling non-Laplacian systems of significant viscoelastic contributions, such as biological cell membranes or polymer blends.
Particle settling velocity is a critical operating parameter in many industrial processes. Severa... more Particle settling velocity is a critical operating parameter in many industrial processes. Several correlations with reasonable accuracy exist for predicting settling velocity for non-spherical particles; however, they all share a common shortfall: they require detailed 3D knowledge of the particle shape and size that is not available in many practical cases, particularly in an on-line industrial context. These correlations are typically therefore unsuitable for use in situations where limited particle geometric information is available or where particle characteristics can change during process operation. This paper presents a method of predicting settling velocity and drag coeffecient with only 2D geometric information that can be obtained from a single side view of a particle, which is feasible to obtain using on-line imaging techniques. The correlation is formed using a large set of data obtained from the literature. We show that for a set of irregular volcanic particles not used to form the correlation, 74% of the predictions are within ±25% error. For comparison, when a standard correlation that uses 3D geometric information is applied to the same set of particles, 81% of predictions are within that error range. The results show that it is possible to obtain predictions using only side-view geometric data with an accuracy close to that achieved by other correlations that require, at minimum, particle surface area and volume. The technique works well when particles have aspect ratios less than five, a range that includes most particle shapes encountered in nature and in industrial processes. The new correlation presented here enables the prediction of settling velocity with reasonable accuracy in an on-line context for many industrial processes, which has not previously been possible.
A major drawback associated with current hot or warm water-based bitumen extraction processes is ... more A major drawback associated with current hot or warm water-based bitumen extraction processes is the high consumption of energy. To address this issue, an aqueous–nonaqueous hybrid bitumen extraction process (HBEP), in which a portion of the diluent (solvent) was added upfront to soak mined oil sands prior to its water-based extraction, was proposed and demonstrated to be feasible to process mineable oil sands at ambient temperatures. This study investigates the effect of adding ethyl cellulose (EC) as a promising demulsifier to the solvent on bitumen recovery and froth quality in the ambient HBEP. The laboratory flotation results clearly showed a significant improvement in froth quality with a negligible setback on bitumen recovery by 100–200 ppm EC addition to the HBEP. Determined by an online visualization method, the addition of EC in solvent to the HBEP was found to further enhance separation kinetics of bitumen from sand grains of real oil sands ores. The addition of EC in solvent also increased the...
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2017
This paper is a review of our work with Scheludko-Exerowa thin liquid film-pressure balance techn... more This paper is a review of our work with Scheludko-Exerowa thin liquid film-pressure balance technique TLF-PBT, the first systematic application of the technique to petroleum systems. New insights were gained in understanding the behavior of petroleum emulsions. We have observed new phenomena in foam films stabilized with sodium naphthenates: long range foam film stratifications and step-wise film thickening at constant capillary pressure. Our modification of TLF-PBT cell allows probing water-in-oil emulsion films with electrical signal, a new technique to study water-in-oil emulsions.
Industrial & Engineering Chemistry Fundamentals, 1976
A2, 9 (1971)l. IV. If it is not possible to draw the (T / G) power-law line, giving C and Q~J , t... more A2, 9 (1971)l. IV. If it is not possible to draw the (T / G) power-law line, giving C and Q~J , then a more laborious (yet conceptually simple) method becomes necessary. (1) Guess value of a, giving b. (2) Correct all data using eq 4A. (4) Repeat steps (1) and (21, adjusting @ until the corrected data have minimum deviation from a best fit power law line. ~~ COMMUNICATIONS This procedure lends itself to computer solution, as fol-(1) Input data, W) , convergence criterion; n = 0. (2) Reduce all data to (7 1 / G) using eq 4A; n = n + 1. (3) Perform straight-line least-squares fit of reduced stress as a function of shear rate; obtain C, QI,~, and the standard deviation, A%. A%(N). If A%(N) lowest so far; store C, 171,l. lows. (4) Store (5) If n > 2 go to (7). (6) Change a, @(N+l) = (7) If convergence has been achieved, go to (9). (8) Fit a quadratic (A% = a0 + a l a + + t. Go to (2). to lowest and two nearest neighbors. Solve for best A%(i). Use a m i n = ~1 / (2~2) .
The landscape of oil production is shifting, with non-conventional oil resources seen as a credib... more The landscape of oil production is shifting, with non-conventional oil resources seen as a credible option to meet the ever-growing demand for oil. In this chapter, the separation of water from heavy oil is considered. The work highlights the fundamental mechanisms of droplet stability, the direct impact of indigenous components of oil and fine particles on droplet interfacial properties, and finally the mechanisms by which droplet interaction and coalescence can be promoted through chemical addition. The chapter aims to provide scientific direction in this challenging research field.
Pressure driven flow of an incompressible Newtonian fluid in a spiral duct of square cross-sectio... more Pressure driven flow of an incompressible Newtonian fluid in a spiral duct of square cross-section was studied both experimentally and numerically. The duct has a curvature ratio (Rc=R/a, where R is the radius of curvature and a is the duct dimension) of 15.1 at the inlet and spirals inwards for nine turns at a uniform rate. A one-component laser-Doppler anemometer was used to measure streamwise velocities. The flow development was determined for Dean number, Dn, of 100, 125, 150, 180 and 250, based on the radius at the flow inlet [Dn=Re/(Rc)1/2, where Re is the Reynolds number, vθ′a/ν]. Steady oscillations in the streamwise direction between 2-cell and 4-cell states, first predicted by Sankar et al. [Phys. Fluids 31, 1348 (1988)], were observed for Dean numbers between 139 and 240. No time dependent flow phenomena were observed. The experimental data are in very good agreement with the numerical simulations, which were based on the parabolized steady three-dimensional Navier–Stokes...
Heat transfer characteristics for a laminar forced convection fully developed flow in an internal... more Heat transfer characteristics for a laminar forced convection fully developed flow in an internally finned circular tube with axially uniform heat flux with peripherally uniform temperature are obtained using a finite element method. For a given fin geometry, the Nusselt number based on inside tube diameter was higher than that for a smooth tube. Also, it was found that for maximum heat transfer there exists an optimum fin number for a given fin configuration. The internal fins are of triangular shape.
The potential of a twisted square pipe for heat transfer applications is examined. A numerical so... more The potential of a twisted square pipe for heat transfer applications is examined. A numerical solution of the energy equation in a rotating frame of reference is used for the analysis. The case of axially uniform wall temperature is considered. The rectilinear nature of the axial velocity profile makes the overall Nusselt number insensitive to changes in Reynolds and Prandtl numbers. However, the swirling motion provides significant enhancement in heat transfer across individual walls. Hence the use of twisted square pipes in a multichannel configuration is proposed.
Settling characteristics of bidisperse suspensions containing light and heavy particles in inclin... more Settling characteristics of bidisperse suspensions containing light and heavy particles in inclined channels have been studied both experimentally and theoretically. The suspension is relatively dilute with a total volume fraction of no more than 0.16. In this dilute range the flow-visualization experiments indicate the formation of distinct zones with clear interfaces between them. There is no evidence of lateral segregation of particles. The convection currents formed near an inclined boundary are transferred to different zones depending on the relative concentration of the two species. Based on the flow-visualization experiments, the well known Ponder-Nakamura-Kuroda (PNK) model has been adopted to predict the settling characteristics of bidisperse suspensions.
Bitumen, a very heavy crude oil, contains both water-soluble and water-insoluble natural surface ... more Bitumen, a very heavy crude oil, contains both water-soluble and water-insoluble natural surface active species. This study shows that complete removal of the water-soluble surface active species from bitumen by water extraction resulted in an increased emulsion stability and that the water-insoluble surface active asphaltenes are the key stabilizing agents for water-in-toluene-diluted bitumen emulsions. Separation of the toluene-diluted bitumen continuous phase from the emulsion by centrifuging at 1, 10, 100, 1000 and 10,000g was conducted. Emulsion stability tests for the separated toluene-diluted bitumen and element analysis of the precipitated asphaltenes indicated that the asphaltenes in the separated organic continuous phase are different from those associated with the water droplet interface. The asphaltenes associated with the interface had a lower H/C ratio and a higher O/C ratio.
Atomic force microscopy (AFM) is frequently used to elucidate complex interactions in emulsion sy... more Atomic force microscopy (AFM) is frequently used to elucidate complex interactions in emulsion systems. However, comparing results obtained with "model" planar surfaces to curved emulsion interfaces often proves unreliable, since droplet curvature can affect adsorption and arrangement of surface-active species, while droplet deformation affects the net interaction force. In the current study, AFM was utilized to study the interactions between a colloidal probe and water droplet. Force magnitude and water droplet deformation were measured in asphaltene and bitumen solutions of different concentrations at various droplet aging times. Interfacial stiffening and an increase in particle-droplet adhesion force were observed upon droplet aging in bitumen solution. As reported in our previous study (Kuznicki, N. P.; Harbottle, D.; Masliyah, J.; Xu, Z. Dynamic Interactions between a Silica Sphere and Deformable Interfaces in Organic Solvents Studied by Atomic Force Microscopy. Langmuir 2016, 32 (38), 9797−9806), a viscoelasticity parameter should be included in the high force Stokes-Reynolds-Young-Laplace (SRYL) equations to account for the interfacial stiffening and non-Laplacian response of the water droplet at longer aging times. However, following the addition of a biodegradable demulsifier, ethyl cellulose (EC), an immediate reduction in both the particle-droplet adhesion force and the rigidity of the water droplet occurred. Following EC addition, the interface reverted back to a Laplacian response and droplet deformation was once again accurately predicted by the classical SRYL model. These changes in both droplet deformation and particle-droplet adhesion, tracked by AFM, imply a rapid asphaltene/bitumen film displacement by EC molecules. The colloidal probe technique provides a convenient way to quantify forces at deformable oil/water interfaces and characterize the in-situ effectiveness of competing surface active species.
Recent studies have successfully measured surface forces using 8 atomic force microscope (AFM) an... more Recent studies have successfully measured surface forces using 8 atomic force microscope (AFM) and modeled surface deformations using the Stokes−Reynolds−Young−Laplace (SRYL) equations for particle−droplet, particle−bubble, droplet−droplet, and bubble−bubble systems in various solutions. The current work focuses on interactions between spherical silica particles and a viscoelastic interface of water droplets in crude oil. The self-assembly of surface active natural polyaromatic molecules (NPAMs) at the oil−water interface has previously been shown to change a viscous dominant oil−water interface to an elastic dominant interface upon aging, due to gradual formation of rigid interfacial networks. AFM was used to measure the interactions between a small silica sphere (D ≈ 8 m) and a deformable water droplet (D ≈ 70 m), which exhibits time-dependent interfacial viscoelasticity in NPAM solutions. Unlike the systems studied previously, the measured deformation shown as a repulsive force over the region of constant compliance could not be modeled adequately by the conventional SRYL equations which are applicable only to purely Laplacian interfaces. As the water droplet ages in NPAM solutions, a rigid "skin" forms at the oil−water interface, with the interface exhibiting increased elasticity. Over a short aging period (up to 15 min in NPAM-in-toluene solution), interfacial deformation is well predicted by the SRYL model. However, upon further exposure to the NPAM solution, droplet deformation is over predicted by the model. Physical properties of this mechanical barrier as a function of interfacial aging were further investigated by measuring interfacial tension, dilatational rheology, and interfacial "crumpling" (non-smooth, non-Laplacian interface) upon droplet volume reduction. By introducing a viscoelasticity parameter to account for interfacial stiffening and using experimentally determined elasticity, we are able to correct this discrepancy and predict droplet deformation under AFM cantilever compression. This parameter appears to be important for modeling non-Laplacian systems of significant viscoelastic contributions, such as biological cell membranes or polymer blends.
Particle settling velocity is a critical operating parameter in many industrial processes. Severa... more Particle settling velocity is a critical operating parameter in many industrial processes. Several correlations with reasonable accuracy exist for predicting settling velocity for non-spherical particles; however, they all share a common shortfall: they require detailed 3D knowledge of the particle shape and size that is not available in many practical cases, particularly in an on-line industrial context. These correlations are typically therefore unsuitable for use in situations where limited particle geometric information is available or where particle characteristics can change during process operation. This paper presents a method of predicting settling velocity and drag coeffecient with only 2D geometric information that can be obtained from a single side view of a particle, which is feasible to obtain using on-line imaging techniques. The correlation is formed using a large set of data obtained from the literature. We show that for a set of irregular volcanic particles not used to form the correlation, 74% of the predictions are within ±25% error. For comparison, when a standard correlation that uses 3D geometric information is applied to the same set of particles, 81% of predictions are within that error range. The results show that it is possible to obtain predictions using only side-view geometric data with an accuracy close to that achieved by other correlations that require, at minimum, particle surface area and volume. The technique works well when particles have aspect ratios less than five, a range that includes most particle shapes encountered in nature and in industrial processes. The new correlation presented here enables the prediction of settling velocity with reasonable accuracy in an on-line context for many industrial processes, which has not previously been possible.
A major drawback associated with current hot or warm water-based bitumen extraction processes is ... more A major drawback associated with current hot or warm water-based bitumen extraction processes is the high consumption of energy. To address this issue, an aqueous–nonaqueous hybrid bitumen extraction process (HBEP), in which a portion of the diluent (solvent) was added upfront to soak mined oil sands prior to its water-based extraction, was proposed and demonstrated to be feasible to process mineable oil sands at ambient temperatures. This study investigates the effect of adding ethyl cellulose (EC) as a promising demulsifier to the solvent on bitumen recovery and froth quality in the ambient HBEP. The laboratory flotation results clearly showed a significant improvement in froth quality with a negligible setback on bitumen recovery by 100–200 ppm EC addition to the HBEP. Determined by an online visualization method, the addition of EC in solvent to the HBEP was found to further enhance separation kinetics of bitumen from sand grains of real oil sands ores. The addition of EC in solvent also increased the...
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2017
This paper is a review of our work with Scheludko-Exerowa thin liquid film-pressure balance techn... more This paper is a review of our work with Scheludko-Exerowa thin liquid film-pressure balance technique TLF-PBT, the first systematic application of the technique to petroleum systems. New insights were gained in understanding the behavior of petroleum emulsions. We have observed new phenomena in foam films stabilized with sodium naphthenates: long range foam film stratifications and step-wise film thickening at constant capillary pressure. Our modification of TLF-PBT cell allows probing water-in-oil emulsion films with electrical signal, a new technique to study water-in-oil emulsions.
Industrial & Engineering Chemistry Fundamentals, 1976
A2, 9 (1971)l. IV. If it is not possible to draw the (T / G) power-law line, giving C and Q~J , t... more A2, 9 (1971)l. IV. If it is not possible to draw the (T / G) power-law line, giving C and Q~J , then a more laborious (yet conceptually simple) method becomes necessary. (1) Guess value of a, giving b. (2) Correct all data using eq 4A. (4) Repeat steps (1) and (21, adjusting @ until the corrected data have minimum deviation from a best fit power law line. ~~ COMMUNICATIONS This procedure lends itself to computer solution, as fol-(1) Input data, W) , convergence criterion; n = 0. (2) Reduce all data to (7 1 / G) using eq 4A; n = n + 1. (3) Perform straight-line least-squares fit of reduced stress as a function of shear rate; obtain C, QI,~, and the standard deviation, A%. A%(N). If A%(N) lowest so far; store C, 171,l. lows. (4) Store (5) If n > 2 go to (7). (6) Change a, @(N+l) = (7) If convergence has been achieved, go to (9). (8) Fit a quadratic (A% = a0 + a l a + + t. Go to (2). to lowest and two nearest neighbors. Solve for best A%(i). Use a m i n = ~1 / (2~2) .
The landscape of oil production is shifting, with non-conventional oil resources seen as a credib... more The landscape of oil production is shifting, with non-conventional oil resources seen as a credible option to meet the ever-growing demand for oil. In this chapter, the separation of water from heavy oil is considered. The work highlights the fundamental mechanisms of droplet stability, the direct impact of indigenous components of oil and fine particles on droplet interfacial properties, and finally the mechanisms by which droplet interaction and coalescence can be promoted through chemical addition. The chapter aims to provide scientific direction in this challenging research field.
Pressure driven flow of an incompressible Newtonian fluid in a spiral duct of square cross-sectio... more Pressure driven flow of an incompressible Newtonian fluid in a spiral duct of square cross-section was studied both experimentally and numerically. The duct has a curvature ratio (Rc=R/a, where R is the radius of curvature and a is the duct dimension) of 15.1 at the inlet and spirals inwards for nine turns at a uniform rate. A one-component laser-Doppler anemometer was used to measure streamwise velocities. The flow development was determined for Dean number, Dn, of 100, 125, 150, 180 and 250, based on the radius at the flow inlet [Dn=Re/(Rc)1/2, where Re is the Reynolds number, vθ′a/ν]. Steady oscillations in the streamwise direction between 2-cell and 4-cell states, first predicted by Sankar et al. [Phys. Fluids 31, 1348 (1988)], were observed for Dean numbers between 139 and 240. No time dependent flow phenomena were observed. The experimental data are in very good agreement with the numerical simulations, which were based on the parabolized steady three-dimensional Navier–Stokes...
Heat transfer characteristics for a laminar forced convection fully developed flow in an internal... more Heat transfer characteristics for a laminar forced convection fully developed flow in an internally finned circular tube with axially uniform heat flux with peripherally uniform temperature are obtained using a finite element method. For a given fin geometry, the Nusselt number based on inside tube diameter was higher than that for a smooth tube. Also, it was found that for maximum heat transfer there exists an optimum fin number for a given fin configuration. The internal fins are of triangular shape.
The potential of a twisted square pipe for heat transfer applications is examined. A numerical so... more The potential of a twisted square pipe for heat transfer applications is examined. A numerical solution of the energy equation in a rotating frame of reference is used for the analysis. The case of axially uniform wall temperature is considered. The rectilinear nature of the axial velocity profile makes the overall Nusselt number insensitive to changes in Reynolds and Prandtl numbers. However, the swirling motion provides significant enhancement in heat transfer across individual walls. Hence the use of twisted square pipes in a multichannel configuration is proposed.
Settling characteristics of bidisperse suspensions containing light and heavy particles in inclin... more Settling characteristics of bidisperse suspensions containing light and heavy particles in inclined channels have been studied both experimentally and theoretically. The suspension is relatively dilute with a total volume fraction of no more than 0.16. In this dilute range the flow-visualization experiments indicate the formation of distinct zones with clear interfaces between them. There is no evidence of lateral segregation of particles. The convection currents formed near an inclined boundary are transferred to different zones depending on the relative concentration of the two species. Based on the flow-visualization experiments, the well known Ponder-Nakamura-Kuroda (PNK) model has been adopted to predict the settling characteristics of bidisperse suspensions.
Bitumen, a very heavy crude oil, contains both water-soluble and water-insoluble natural surface ... more Bitumen, a very heavy crude oil, contains both water-soluble and water-insoluble natural surface active species. This study shows that complete removal of the water-soluble surface active species from bitumen by water extraction resulted in an increased emulsion stability and that the water-insoluble surface active asphaltenes are the key stabilizing agents for water-in-toluene-diluted bitumen emulsions. Separation of the toluene-diluted bitumen continuous phase from the emulsion by centrifuging at 1, 10, 100, 1000 and 10,000g was conducted. Emulsion stability tests for the separated toluene-diluted bitumen and element analysis of the precipitated asphaltenes indicated that the asphaltenes in the separated organic continuous phase are different from those associated with the water droplet interface. The asphaltenes associated with the interface had a lower H/C ratio and a higher O/C ratio.
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Papers by Jacob Masliyah