Single-drop transport in a kühni extraction column

Seikova, I.; Gourdon, Christophe; Casamatta, G.

doi:10.1016/0009-2509(92)85164-7

Cited by 14 publications

(11 citation statements)

References 8 publications

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“…Drop trajectories were shown to be complex [15], so a simple correlation of drop characteristic velocities is not to be expected.…”

Section: Introductionmentioning

confidence: 99%

“…Casamatta and co-workers in Toulouse have set up an automated system for drop breakage probability measurements in a single stage (and later a three-stage system) of 100 mm diameter [15].. Their results were correlated in a simple way; an improved approach is described in this paper. Drop trajectories were shown to be complex [15], so a simple correlation of drop characteristic velocities is not to be expected.…”

Section: Introductionmentioning

confidence: 99%

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Single liquid drop breakage probabilities and characteristic velocities in Kühni columns

et al. 1995

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Studies have been made on the extent and mechanism of breakage of single liquid drops of organic liquids immiscible in water rising through short sections of Kuhni liquid-liquid extraction columns. Information on drop breakage probabilities is required for calculation of drop size distributions developed under counter-current column operating conditions. The breakage probability data from two small diameter Kuhni columns containing one, three or five stages have been correlated as a function of a modified Weber number based on the shearing forces on drops. The critical condition for breakage, giving a maximum stable drop size, is based on an impeller Weber number. Characteristic velocities of drops were measured relative to terminal velocity and the ratio was tentatively correlated with a function of an impeller Reynolds number together with the fractional free area of the perforated plates used to separate compartments. The drops were found to break predominantly at the holes in the plates, not at the turbine, in the region of transitional Reynolds number used in this work. The results apply only to non-turbulent conditions so further work on larger diameter equipment is called for.

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“…Drop trajectories were shown to be complex [15], so a simple correlation of drop characteristic velocities is not to be expected.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Single liquid drop breakage probabilities and characteristic velocities in Kühni columns

et al. 1995

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“…Thus, Haunold et al (1990), Seikova et al (1992), and Fang et al (1995) all measured the velocity of single drops through a Kü hni column, while Fan et al (1987) measured similar velocities in an RDC. Gourdon et al(1991) used both a Kü hni and a pulsed sieve plate column.…”

Section: Introductionmentioning

confidence: 99%

Measurement of Drop Rise Velocities within a Kühni Extraction Column

Kentish

Stevens

Pratt

1997

Ind. Eng. Chem. Res.

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A new method is presented for the determination of droplet rise velocities within liquid-liquid extraction columns. This method utilizes the difference between the static drop size distribution as measured by a photographic technique and the dynamic drop size distribution as measured by a capillary probe technique. The ratio of the two volume densities multiplied by the average flow velocity is then a direct measure of the individual drop velocity. Droplet velocities measured using this technique are consistent with single drop velocities measured by other workers at low holdups. However, at higher holdups the droplet velocities converge toward a single value rather than retaining a range of drop size dependent values.

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“…Seikova et al [17] studied the residence time behaviour of single drops in a Kühni column. Their observations yielded the droplet size specific axial back-mixing coefficient which describes the random character of the drop motion due to the flow patterns of the continuous phase.…”

Section: Axial Dispersionmentioning

confidence: 99%

Simulation of the Fluid Dynamics of Solvent Extraction Columns from Single Droplet Parameters

Modes¹,

Bart

Rodriguez-Perancho

et al. 1999

Chem. Eng. Technol.

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A droplet population balance model is used to simulate the hydrodynamic behaviour of solvent extraction columns. This model describes the axial change of local column hold-up and local droplet size distributions caused by basic phenomena such as droplet rise, axial dispersion, and droplet break-up and coalescence. In order to reduce the effort invested in experimental scale-up, single droplet experiments were performed in small-scale laboratory devices. A Rotating Disc Contactor (RDC) with 5 compartments was used for this purpose. The single droplet movement is investigated by using a light source to reproduce the three dimensional particle trajectories on a two-dimensional screen. The resulting pictures are analysed by digital image processing. The experiments were performed for different droplet sizes under different agitation and throughput conditions. Droplet rise is found to slow down with increasing agitation whereas higher continuous phase throughput shows only a weak influence on the relative rising velocity. Simultaneously the axial dispersion coefficient decreases at higher agitation and continuous phase flow rates. Based on these single droplet parameters, the population balance equation is solved numerically for a RDC column using a Galerkin method.

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Single-drop transport in a kühni extraction column

Cited by 14 publications

References 8 publications

Single liquid drop breakage probabilities and characteristic velocities in Kühni columns

Single liquid drop breakage probabilities and characteristic velocities in Kühni columns

Measurement of Drop Rise Velocities within a Kühni Extraction Column

Simulation of the Fluid Dynamics of Solvent Extraction Columns from Single Droplet Parameters

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