Evolution of drop size distribution in liquid–liquid dispersions for various impellers**This paper was the winner of the first North American Mixing Forum Student Award, June, 1997.

Zhou, Genwen; Kresta, Suzanne M.

doi:10.1016/s0009-2509(97)00437-5

Cited by 84 publications

(19 citation statements)

References 9 publications

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“…Silicon oil has actually been used as dispersed phase in previous work, e.g. [3] and [8]. It is colourless and transparent which is ideal in this case.…”

Section: Liquid-liquid Model Systemmentioning

confidence: 99%

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LDA‐Measurements in a Stirred Tank With a Liquid‐Liquid System at High Volume Percentage Dispersed Phase

Svensson

Rasmuson

2004

Chem Eng & Technol

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The purpose of this study is to evaluate how the flow is influenced by the volume percentage of dispersed phase in a liquid-liquid system. A novel model system consisting of two refraction index matched immiscible liquids is presented along with experimental velocity vector fields of the continuous phase that utilises the non-intrusive Laser-Doppler-Anemometry technique. Three velocity components have been measured inside a baffled cylindrical tank, stirred with a six-bladed Rushtonimpeller. The experiments show that the vortex below the impeller is stretched, primarily in the radial direction, with increasing dispersed phase content. A small change in the shape of the vortex above the impeller can also be observed. The turbulence is dampened with increasing dispersed volume fraction.

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“…Silicon oil has actually been used as dispersed phase in previous work, e.g. [3] and [8]. It is colourless and transparent which is ideal in this case.…”

Section: Liquid-liquid Model Systemmentioning

confidence: 99%

“…So far, mostly dilute multiphase systems have been studied using non-intrusive techniques, such as Particle Dynamics Analysis (PDA), e.g. [3]. At higher volume percentage dispersed phase content, intrusive methods like endoscopes have been used to obtain measurements deep inside vessels, e.g.…”

Section: Introductionmentioning

confidence: 99%

LDA‐Measurements in a Stirred Tank With a Liquid‐Liquid System at High Volume Percentage Dispersed Phase

Svensson

Rasmuson

2004

Chem Eng & Technol

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“…Die räumlich und zeitlich variierenden Mischeigenschaften dieser Apparate führen häufig zu einem Verlust an Selektivität und der Produktqualität. Das Rühren nichtmischbarer Phasen in einem typischen, konventionellen Multiphasenkontaktor erzeugt Tropfen in einem Größen-bereich von wenigen zehn Mikrometern bis hin zu Millimetern, womit die spezifische Grenzfläche ebenso in Zeit und Raum variiert [14,15]. Damit ergeben sich für die verschiedenen Tropfen verschiedene lokale Reaktionsraten, auch weil die Temperatur durch Hot-Spot-Bildung aufgrund des inhomogenen Mischens zusätzlich von Ort zu Ort variieren kann.…”

Section: Introductionunclassified

Redispersion Microreactor System for Phase Transfer Catalyzed Esterification

Jovanović

Rebrov

Nijhuis

et al. 2011

Chemie Ingenieur Technik

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Redispersion Microreactor System for Phase Transfer Catalyzed EsterificationAn interdigital mixer -redispersion capillary assembly was applied to prevent the liquid-liquid bubbly flow coalescence in microreactors. The redispersion capillary consisted of 1 mm long and 0.25 mm inner-diameter constrictions placed every 0.50 m along the channel length. The system was tested on the phase transfer catalyzed esterification to produce benzyl benzoate. The application of constrictions to prevent coalescence resulted in a better reproducibility compared to a capillary without the constrictions. By controlling the total flow rate and the aqueous-to-organic ratio the bubbly flow surface-volume ratio could be increased up to 230 700 m 2 m -3. Compared to the conventional phase transfer catalyzed esterification, the continuous operation in the interdigital-redispersion capillary assembly eliminated the use of solvents and bases, removing an energy intensive step of distillation, while increasing process safety.

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“…According to the IMM interdigital mixer specifications, flow rates higher than 0.80 mL min -1 should be used for its optimal performance. Therefore, it can be concluded that slug flow, a surface tension-dominated flow pattern [2,15], occurs under flow conditions below the mixer efficiency range. The transition from the slug/bubbly flow to bubbly flow occurs at approximately the same aqueous and organic flow rates for both the 0.50 and 0.75 mm capillaries, indicating that the flow pattern is determined by the mixer rather than the capillary.…”

Section: Hydrodynamicsmentioning

confidence: 99%

“…PTC reactions are most commonly performed in stirred tanks where the inhomogeneous mixing often results in loss of selectivity and product quality. The stirring of the phases in the conventional stirred-tank multiphase reactor generates a wide range of drop sizes, with diameters varying from tens of micrometers to millimeters, resulting in a considerable variation in interfacial surface area from one drop to another [14,15]. Consequently, different rates of reaction are obtained for different drops, along with hot spot formation due to inhomogeneous mixing, resulting in yield variation from one batch to another.…”

Section: Introductionmentioning

confidence: 99%

Redispersion Microreactor System for Phase Transfer‐Catalyzed Esterification

et al. 2011

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An interdigital mixer-redispersion capillary assembly was applied to prevent the liquid-liquid bubbly flow coalescence in microreactors. The redispersion capillary consisted of 1-mm-long 0.25 mm inner-diameter constrictions, placed every 0.50 m along the channel length. The system was tested on the phase transfer-catalyzed esterification to produce benzyl benzoate. The application of constrictions to prevent coalescence resulted in a better reproducibility and higher conversion compared to a capillary without constrictions. The bubbly flow generated by the interdigital mixer-redispersion capillary assembly was found to be independent of the redispersion capillary inner diameters (0.50 and 0.75 mm) while being highly dependent on the flow rates. By controlling the total flow rate and the aqueousto-organic ratio, the bubbly flow surface-to-volume ratio could be increased up to 230 700 m 2 m -3. Compared to the conventional phase transfer-catalyzed esterification, the continuous operation in the interdigital mixer-redispersion capillary assembly eliminated the use of solvents and bases, removing an energy-intensive step of distillation while increasing process safety.

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Evolution of drop size distribution in liquid–liquid dispersions for various impellers**This paper was the winner of the first North American Mixing Forum Student Award, June, 1997.

Cited by 84 publications

References 9 publications

LDA‐Measurements in a Stirred Tank With a Liquid‐Liquid System at High Volume Percentage Dispersed Phase

LDA‐Measurements in a Stirred Tank With a Liquid‐Liquid System at High Volume Percentage Dispersed Phase

Redispersion Microreactor System for Phase Transfer Catalyzed Esterification

Redispersion Microreactor System for Phase Transfer‐Catalyzed Esterification

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