Longitudinal concentration distribution of droplets in multi-stage bubble columns for gas-liquid-liquid systems.

Kato, Yasuo; Kago, Tokihiro; Morooka, Shigeharu

doi:10.1252/jcej.17.429

Cited by 16 publications

(22 citation statements)

References 6 publications

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“…Although voluminous literature exists on different aspects of bubble columns involving a single liquid, very little information is available on hydrodynamics and mass transfer characteristics of gas-liquid-liquid bubble columns, despite their considerable practical importance. Kato et al (1984) investigated the hydrodynamics in a relatively small diameter multistage bubble column with air-water-kerosene system and presented correlations for gas hold-up and longitudinal droplet dispersion coefficient. Their correlations, however, are of limited applicability as the effect of the fraction of * To whom correspondence should be addressed; presently with Chemical Engineering Science Div.. National Bureau of Standards.…”

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confidence: 99%

Gas holdup in a bubble column with immikible liquid mixtures

Bandyopadhyay¹,

Ray

Dutta

1988

Can J Chem Eng

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Experimental measurement of gas holdup was carried out in a medium-size gas-liquid-liquid bubble column with a multiple nozzle sparger plate using air, water and organic liquids. It was found that the fractional holdup depends on gas velocity, liquid properties, phase inversion in the liquid mixture as well as spreading coefficient of the organic liquid. In the presence of a liquid with a negative spreading coefficient the holdup is a minimum at the phase inversion point. but the reverse is true for a liquid with a positive coefficient of spreading. Observed bubble characteristics have been discussed. Correlations for gas holdup have been developed for different ranges of liquid composition.Des mesures experimentales ont tte effectuees sur la retenue de gaz dans une colonne il bulles gaz-liquide-liquide de taille moyenne avec un plateau aspergeur a orifices multiples utilisant de l'air, de I'eau et des liquides organiques. On a trouvk que la retenue fractionnelle est fonction de la vitesse du gaz. des propriktks du liquide, de I'inversion des phases dans le mClange liquide, ainsi que du coefficient de dispersion du liquide organique. En presence d'un liquide ayant un coefficient de dispersion nCgatif, la retenue est minimum au point d'inversion de phases, mais I'inverse est vrai pour un liquide dont le coefficient de dispersion est positif. Les caractkristiques des bulles observees ont kte CtudiCes.Des corrClations pour la retenue de paz ont it6 klaborkes pour diffkrentes gammes de compositions de liquides.

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confidence: 99%

Gas holdup in a bubble column with immikible liquid mixtures

Bandyopadhyay¹,

Ray

Dutta

1988

Can J Chem Eng

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“…This implies that the spreading coefficient of the organic liquid on water is not the single factor affecting the gas hold-up. The lower interfacial tension and the higher apparent viscosity in the G-L-L system as compared to the G-L system may contribute as well: Kato et al 9 found that the gas hold-up is 10 -15% lower in G-L-L systems than in G-L systems. This reduction in the gas hold-up has been attributed to an increase in the apparent viscosity of the bulk liquid resulting from the presence of the dispersed phase.…”

Section: Resultsmentioning

confidence: 99%

“…Experimental hydrodynamic characteristics and mass transfer data have been reported for packed columns [3][4][5]7 , for a spray column 8 and for bubble columns [9][10][11] . Ziebland and Hackl 8 made first attempts to describe the phenomena associated with the introduction of an inert gas into the spray column.…”

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confidence: 99%

Gas-Agitated Liquid-Liquid Extraction in a Spray Column

Sovilj

Kneževic

1994

Collect. Czech. Chem. Commun.

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The hydrodynamic characteristics of the air-water-toluene three-phase system in a spray extraction column at 20 °C were examined. The average and local hold-up data of the dispersed phase were determined in dependence on the flow rates of the continuous, dispersed and gaseous phases. The average gas phase hold-up was also measured and analyzed. A comparison was made of the hydrodynamic characteristics of the two-phase (water-toluene) and three-phase (air-water-toluene) systems.With respect to the dispersed phase hold-up, a spray extraction column can operate in three modes of packing of the dispersed phase drops 1,2 : dispersed, restrained, and dense. The efficiency is relatively low when the column is operated in the dispersed or restrained drop packing mode, mainly due to a high axial mixing in the continuous phase. An increased efficiency of the spray extraction column is attained with the dense packing of the dispersed phase drops, where the axial mixing in the two phases is significantly decreased.The efficiency of non-mechanically agitated extraction columns with different packings can be considerably increased by introducing an inert gas as a mixing agent in the two-phase system 3-5 . The energy thus introduced increases the turbulence within the now three-phase, gas-liquid-liquid (G-L-L) system, which brings about improved dispersion of the droplets and, consequently, a higher hold-up and a larger mass transfer area 3 . Priestley and Ellis 5 observed that the dispersed phase droplets were smaller and there was more backmixing in the continuous phase when a gas was introduced into the packed extraction column. Galkin et al. 6 found the largest reduction of the height equivalent to a theoretical stage (HETS) in plate extraction columns with superficial gas velocities of 0.02 -0.03 m s −1 . The authors concluded that this way of energy introduction was more efficient than by stirring or pulsation of the column.Gas-Agitated Liquid-Liquid Extraction

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“…The same authors (24) measured the average gas holdups, the longitudinal distribution of the volume fraction of a dispersed liquid (droplet), and the longitudinal dispersion coefficients of a dispersed liquid, using two bubble columns (0.066-and 0.122 m i.d.) On the other side, Kato et al (27) extended the studies of Hatate et al (23,24) from a single-stage to the multistage bubble columns of the same diameter. Their columns were operated batchwise or continuously with respect to the liquids.…”

Section: Drop Size and Gas Phase Holdupmentioning

confidence: 92%

Hydrodynamics of gas-agitated liquid-liquid extraction columns

Sovilj

2012

ACTA PERIOD TECHN

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Although the non-agitated extraction columns (spray column, packed column, perforated plate column, sieve plate column, etc) can handle high flow rates and are simple and cheap, there have been relatively few applications of these columns because they suffer from serious backmixing of the continuous phase. It was shown that the backmixing is reduced when the spray column is operated with dense packing of drops. Another way of increasing the efficiency of a non-agitated extraction column is to introduce an inert gas (air, nitrogen, oxygen) as a mixing agent in the two-phase liquid-liquid (L-L) system. This method of energy introduction increases the turbulence within the new three-phase gas-liquid-liquid (G-L-L) system, which causes an improved dispersion of droplets, and, consequently, a higher dispersed phase holdup and therefore a great mass transfer area. The present study reports the hydrodynamics in the non-agitated extraction columns, as well as the axial dispersion for the two- and three-phase systems

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Longitudinal concentration distribution of droplets in multi-stage bubble columns for gas-liquid-liquid systems.

Cited by 16 publications

References 6 publications

Gas holdup in a bubble column with immikible liquid mixtures

Gas holdup in a bubble column with immikible liquid mixtures

Gas-Agitated Liquid-Liquid Extraction in a Spray Column

Hydrodynamics of gas-agitated liquid-liquid extraction columns

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