Longitudinal Mixing in a Pulsed Sieve-Plate Extraction Column

Mar, Brian W.; Babb, A. L.

doi:10.1021/ie51396a032

Cited by 34 publications

(18 citation statements)

References 4 publications

(5 reference statements)

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“…The axial dispersion coefficient, E , was calculated from the steady-state concentration profiles with the following differential material balance equation, originally described by Mar and Babb (1959):…”

Section: Dc/dzmentioning

confidence: 99%

Effect of unfavorable continuous phase density gradient on axial mixing

Holmes¹,

Karr²,

Baird

1991

AIChE Journal

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Section: Dc/dzmentioning

confidence: 99%

Effect of unfavorable continuous phase density gradient on axial mixing

Holmes¹,

Karr²,

Baird

1991

AIChE Journal

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“…Therefore, if the model applies, a plot of In Cc against z will be linear and E can be determined from the slope (Gilliland and Mason, 1949;Mar and Babb, 1959).…”

mentioning

confidence: 99%

Continuous-Phase Axial Dispersion in Liquid-Liquid Spray Towers

Henton¹,

Cavers²

1970

Ind. Eng. Chem. Fund.

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The diffusion model applies to axial dispersion in the continuous phase of liquid-liquid spray columns. Continuous-phase axial dispersion coefficients were determined for methyl isobutyl ketone dispersed in water.A sodium chloride tracer, insoluble in the dispersed phase, was injected into the column and its steady-state concentration was measured upstream in the continuous phase from the plane of injection. The dispersion coefficient was unaffected by continuous-phase superficial velocity over the velocity range investigated, but decreased with increased dispersed-phase superficial velocity. It increased with column diameter but was unaffected by column length. It increased with drop size at constant dispersed-phase superficial velocity; however, it remained approximately constant with drop size when the number of drops per unit volume of column was maintained constant. Some disagreement with earlier results was noted; however, dispersion numbers calculated from the present study superimpose roughly on those published earlier for liquids in packed beds.Internal sampling of liquid-liquid spray extraction columns, begun by Geankoplis and Hixson (1950) and continued by others-e.g., Gier and Hougen (1953), Vogt and Geankoplis (1954), and Cavers and Ewanchyna (1957)-revealed a sharp change, or end effect, in the continuous-phase concentration at the inlet of that phase to the column. Newman (1952) pointed out that this end effect could be explained in terms of backmixing of the continuous phase; however, part of it arises from mass transfer between the continuous phase and the drops while these are agitated at the column interface prior to coalescence (Cavers and Ewanchyna, 1957). Miyauchi and Vermeulen (1963), among others, considered longitudinal dispersion from the standpoint of theory, and Brutvan (1958) and Hazlebeck and Geankoplis (1963) studied it experimentally in spray towers. Letan and Kehat (1965, 1968) from heat transfer work in such columns, confirmed that the main mechanism of backmixing is transport in drop wakes, in accord with the findings of Hendrix et al. (1967) for mass transfer. Recently, the whole subject of the effect of axial mixing on mass transfer in extraction columns ivas reviewed by Li and Ziegler (1967); Mixon et al. (1967)

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“…Axial dispersion in the continuous aqueous phase was measured in two different ways. In both the non-mass-transfer and the mass-transfer runs, the classical steady-state backmixing method was used, with a nontransferring dye tracer. The dye concentration in the drawn samples was measured by a precalibrated Brinckman PC800 colorimeter.…”

Section: Methodsmentioning

confidence: 99%

Effects of Mass Transfer on the Hydrodynamic Behavior of a Karr Reciprocating Plate Column

Aravamudan

Baird

1999

Ind. Eng. Chem. Res.

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A 5 cm internal diameter Karr reciprocating plate column has been operated in countercurrent liquid−liquid flow in the absence of mass transfer and with mass transfer of i-propanol from the dispersed phase (Isopar M) to the continuous phase (water). The effect of mass transfer is to increase the drop diameter, while the holdup is reduced and axial dispersion is increased. Although an unstable density gradient was created by the mass-transfer process, earlier models developed under non-mass-transfer conditions, based on Kolmogoroff's isotropic turbulence theory, were not applicable in describing the enhancement in axial mixing. It was concluded that the density gradient effect was masked by the effect of the larger drops which were formed because of mass-transfer-induced coalescence. Mass-transfer coefficients for the dispersed phase were found to show the same trends as the Handlos and Baron oscillating drop model.

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Longitudinal Mixing in a Pulsed Sieve-Plate Extraction Column

Cited by 34 publications

References 4 publications

Effect of unfavorable continuous phase density gradient on axial mixing

Effect of unfavorable continuous phase density gradient on axial mixing

Continuous-Phase Axial Dispersion in Liquid-Liquid Spray Towers

Effects of Mass Transfer on the Hydrodynamic Behavior of a Karr Reciprocating Plate Column

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