Robust Flash Calculation Algorithm for Microemulsion Phase Behavior

Khorsandi, Saeid; Johns, Russell T.

doi:10.1007/s11743-016-1877-9

Cited by 34 publications

(28 citation statements)

References 45 publications

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“…An analogous description can be made for γ mw . This approach for the critical tie line calculation is consistent with that of Khorsandi and Johns. , The simplest expressions that satisfy the required limits in eq are For the type II– environment, the oil–microemulsion interfacial tension reaches a maximum at the oil–water boundary of the ternary diagram and a minimum at the critical point. That is, Similar observations can be made for the microemulsion–water interfacial tension in the type II+ environment.…”

Section: Methodssupporting

confidence: 71%

“…The oil–microemulsion and microemulsion–water interfacial tension models for type III are based on the bicritical points at HLD L and HLD U where the tie triangle merges to a two-phase tie line. Therefore, the following conditions must hold: These limits are consistent with the earlier models developed by Ghosh and Johns and Khorsandi and Johns. , Using the model for γ ow in eq and the principal curvature definitions shown in Appendix S1, a simple model that satisfies the conditions in eq is where c c 2 (κ + κ̅) = ( c γ HLD U 2 + γ ow min )/(2HLD U 2 ) from eq . This observation allows for the estimation of oil–microemulsion and microemulsion–water interfacial tensions from oil–water interfacial tensions or vice versa.…”

Section: Methodssupporting

confidence: 60%

“…For a small number of components, the Gibbs phase rule restricts the value of N . The HLD concept has been extensively used to define surfactant affinity in different microemulsion phase behavior models because of its simplicity in accounting for changes in multiple formulation variables simultaneously. − …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Coupled Interfacial Tension and Phase Behavior Model Based on Micellar Curvatures

Torrealba

Johns

2017

Langmuir

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This article introduces a consistent and robust model that predicts interfacial tensions for all microemulsion Winsor types and overall compositions. The model incorporates film bending arguments and Huh's equation and is coupled to phase behavior so that simultaneous tuning of both interfacial tension (IFT) and phase behavior is possible. The oil-water interfacial tension and characteristic length are shown to be related to each other through the hydrophilic-lipophilic deviation (HLD). The phase behavior is tied to the micelle curvatures, without the need for using the net average curvature (NAC). The interfacial tension model is related to solubilization ratios in order to introduce a coupled interfacial tension-phase behavior model for all phase environments. The approach predicts two- and three-phase interfacial tensions and phase behavior (i.e., tie lines and tie triangles) for changes in composition and HLD input parameters, such as temperature, pressure, surfactant structure, and oil equivalent alkane carbon number. Comparisons to experimental data show excellent fits and predictive capability.

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Section: Methodssupporting

confidence: 71%

Section: Methodssupporting

confidence: 60%

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Coupled Interfacial Tension and Phase Behavior Model Based on Micellar Curvatures

Torrealba

Johns

2017

Langmuir

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“…The effects of the change of any of the variables directly appearing in the HLD equation (temperature, S, ACN, single surfactant Cp) on the WIII body of a pure component SOW ternary are fairly understood through 2D representations, but not at a higher dimension. The computer simulation models, which are in progress, contain few variables and are often experimentally verified only by changing salinity [30,[256][257][258][259]. Additionally, this is still a too simple approach, not enough to easily deal with a real system containing commercial surfactants, and even surfactant mixtures, crude oil, and reservoir brine.…”

Section: Combination Of Three Single Effects Produced By Three Variabmentioning

confidence: 99%

How to Attain Ultralow Interfacial Tension and Three‐Phase Behavior with Surfactant Formulation for Enhanced Oil Recovery: A Review. Part 4: Robustness of the Optimum Formulation Zone Through the Insensibility to Some Variables and the Occurrence of Complex Artifacts

Salager

Antón

Arandia

et al. 2017

J Surfact & Detergents

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In enhanced oil recovery, not only the low‐tension performance, but also the robustness at optimum formulation is an important issue. The fourth part of our review series is dedicated to robustness, defined as the width of the zone exhibiting three‐phase behavior around the optimum formulation, whatever the scanned variable. It is first corroborated from a screening of the available data in the literature that the tension minimum is inversely proportional to the square of the three‐phase range in the HLD scale. However, since there is still an inaccuracy of about a factor 10 in the tension minimum, some significant improvement can be attained in some cases by increasing the three‐phase behavior width in two ways. The first approach consists of finding systems that are insensitive to some formulation variable such as temperature, surfactant mixture composition or concentration, and water‐to‐oil ratio. The second way is to produce an artifact through which the optimum formulation is produced twice in a scan. If the distance between the two events in the scan is reduced down to be zero, their corresponding three‐phase behavior zones merge and result in a wider WIII region with a low tension. Several cases of such events are reported: alkaline scans, anionic‐nonionic and anionic‐cationic mixture changes, linear change in composition in three‐surfactant mixture, partial precipitation from a surfactant mixture in a salinity scan, and excessive partitioning of polyethoxylated nonionics. More complex transitions with three effects in a single scan or three concomitantly scanned variables show even more possibilities in practice.

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“…For the type II+ lobe, the data is captured assuming the critical point is located in negative composition space, resulting in a non-vanishing tie-line length as the critical point is approached. This behavior is relevant for systems that exhibit phase separation between a micelle-rich and a micelle-poor phase as the critical point is approached (Kamei et al, 2002;Khorsandi and Johns, 2016).…”

Section: Model Propertiesmentioning

confidence: 99%

Curvature-Based Equation of State for Microemulsion-Phase Behavior

2018

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An accurate description of microemulsion phase behavior is critical for many industrial applications, including surfactant flooding in enhanced oil recovery. Recent phase behavior models have assumed constant-shaped micelles, typically spherical, using net average curvature (NAC), which is not consistent with scattering and microscopy experiments that suggest changes in shapes of the continuous and discontinuous domains. Based on the strong evidence of varying micellar shape, principle micellar curves were recently used to model interfacial tensions (IFT). Huh's scaling equation was also coupled to this IFT model to generate phase behavior estimates, but without accounting for micellar shape. In this paper, we present a novel microemulsion phase behavior equation-of-state (EoS) that accounts for changing micellar curvatures under the assumption of a general prolate spheroidal geometry, instead of through Huh's equation. This new EoS improves phase behavior modeling capabilities and eliminates the use of NAC in favor of a more physical definition of characteristic length. Our new EoS can be used to fit and predict microemulsion phase behavior irrespective of IFT data availability. For the cases considered, the new EoS agrees well with experimental data for scans in both salinity and composition. The model also predicts phase behavior data for a wide range of temperature and pressure, and is validated against dynamic scattering experiments, to show the physical significance of the approach.

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Robust Flash Calculation Algorithm for Microemulsion Phase Behavior

Cited by 34 publications

References 45 publications

Coupled Interfacial Tension and Phase Behavior Model Based on Micellar Curvatures

Coupled Interfacial Tension and Phase Behavior Model Based on Micellar Curvatures

How to Attain Ultralow Interfacial Tension and Three‐Phase Behavior with Surfactant Formulation for Enhanced Oil Recovery: A Review. Part 4: Robustness of the Optimum Formulation Zone Through the Insensibility to Some Variables and the Occurrence of Complex Artifacts

Curvature-Based Equation of State for Microemulsion-Phase Behavior

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