Airlift Reactors: Characteristics, Applications and Design Considerations

Chisti, M.Y.; Moo‐Young, Murray

doi:10.1080/00986448708912017

Cited by 261 publications

(158 citation statements)

References 64 publications

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“…9 was representative of all the fluids tested, although the specific value of the k L /d B ratio depended on the concentration of the cellulose fibers in the slurry. The mean experimental value of the k L /d B ratio in 2% SF slurry was 0.0261 s −1 , or within 47% of the value calculated with the independently developed empirical [1,14,23] relationship…”

Section: Gas-liquid Mass Transfersupporting

confidence: 74%

“…The parameter E is essentially the ratio of the instantaneous mass transfer rate to the maximum possible rate of oxygen transfer [1]. The specific power input due to aeration was calculated [1,14] using the equation…”

Section: The Measurementsmentioning

confidence: 99%

“…Whereas the stirred hybrid airlift reactor has been shown to perform well, little is known about such devices compared to the knowledge base for the design of conventional stirred [2,13] and airlift bioreactors [1,5,14,15]. This work reports on hydrodynamic and mass transfer characterization of a large (>1 m 3 ) impeller-assisted airlift bioreactor.…”

Section: Introductionmentioning

confidence: 99%

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Oxygen transfer and mixing in mechanically agitated airlift bioreactors

Chisti

Jäuregui‐Haza²

2002

Biochemical Engineering Journal

152

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Gas holdup, mixing, liquid circulation and gas-liquid oxygen transfer were characterized in a large (∼1.5 m 3 ) draft-tube airlift bioreactor agitated with Prochem ® hydrofoil impellers placed in the draft-tube. Measurements were made in water and in cellulose fiber slurries that resembled broths of mycelial microfungi. Use of mechanical agitation generally enhanced mixing performance and the oxygen transfer capability relative to when mechanical agitation was not used; however, the oxygen transfer efficiency was reduced by mechanical agitation. The overall volumetric gas-liquid mass transfer coefficient declined with the increasing concentration of the cellulose fiber solids; however, the mixing time in these strongly shear thinning slurries was independent of the solids contents (0-4% w/v). Surface aeration never contributed more than 12% to the total mass transfer in air-water.

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Section: Gas-liquid Mass Transfersupporting

confidence: 74%

Section: The Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Oxygen transfer and mixing in mechanically agitated airlift bioreactors

Chisti

Jäuregui‐Haza²

2002

Biochemical Engineering Journal

152

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“…The simplicity of their design and construction, better defined flow patterns, low power input, low shear fields, good mixing and extended aseptic operation, made possible by the absence of stirrer shafts, seals and bearings, are important advantages of airlift reactors in fermentation applications (Chisti and Moo-Young, 1987;Chisti, 1989;Moresi, 1981).…”

Section: Introductionmentioning

confidence: 99%

The effects of geometry and operational conditions on gas holdup, liquid circulation and mass transfer in an airlift reactor

Gouveia

Hokka

Badino-Jr

2003

Braz. J. Chem. Eng.

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-In airlift reactors transport phenomena are achieved by pneumatic agitation and circulation occurs in a defined cyclic pattern through a loop. In the present work, the effect of geometrical relations on gas holdup and liquid velocity, and consequently on the gas-liquid mass transfer coefficient, was studied in a 6-liter airlift bioreactor with A D /A R = 0.63; A D , downcomer cross-sectional area, and A R , riser cross-sectional area. Measurements of the volumetric oxygen transfer coefficient (k L a) were taken in a water-air system using a modified sulfite oxidation method. Different conditions were examined by varying parameters such as superficial air velocity in the riser (U GR ), bottom clearance (d 1 ) and top clearance (d 2 ). It was observed from the experimental results that d 1 and d 2 have a remarkable effect on k L a values. The effect is due to their influence on gas holdup and liquid velocity, consequently affecting k L a. Superficial air velocity in the riser (U GR ) ranged from 0.0126 to 0.0440 m.s -1 and k L a varied between 40 to 250 h -1 , whereas gas holdup (ε) reached values up to 0.2. The volumetric oxygen transfer coefficient (k L a), gas holdup in the riser (ε R ) and downcomer (ε D ) and superficial liquid velocity in the riser (U LR ) for all the geometrical relations were successfully correlated with dimensionless numbers, namely, the Sherwood number (

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“…An airlift system is an example of gas-liquid contacting devices for which its application in biotechnology area has grown significantly in recent years [2,3]. It is considered that the liquid-phase behavior in bioreactors and in coal liquefaction can be simulated by dilute non-viscous aqueous alcohol solutions.…”

Section: Introductionmentioning

confidence: 99%

Liquid-Phase Volumetric Mass Transfer Coefficient for Dilute Alcohol Solution in an External-Loop Airlift Reactor with a Porous Plate (Effect of Pore Size of Porous Plate)

Miyahara

Nagatani

Ohnishi

et al. 2011

JAPANESE JOURNAL OF MULTIPHASE FLOW

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The aim of this work is to investigate the influence of the addition of alcohol on the behavior of an external-loop airlift reactor with a porous plate. The mass transfer parameter in dilute aqueous solutions of three aliphatic alcohols (methanol, ethanol and n-propanol) was examined using five kinds of porous plates. The results showed that dilute alcohol addition enhanced dramatically liquid-phase volumetric mass transfer coefficient, k L a R , in the riser, especially led to the remarkable enhancement of that for the porous plate having small pore diameter due to smaller bubble diameter than with water system. This behavior is enhanced by alcohols with long carbon chain lengths probably due to the inhibition of bubble-bubble coalescence at the porous plate and in the liquid. This surprising result might be explained by a strong increase in k L values in liquid-phase volumetric mass transfer coefficient due to the increasing amount of small bubbles leading to large partial pressure of transfer component within bubbles based on capillary pressure as explained previously [1]. Also, the results showed that the liquid-phase volumetric mass transfer coefficient increased with the concentration of alcohol, but led to reduction of the volumetric mass transfer coefficient over any critical concentration for each porous plate. Moreover, empirical equation for liquid-phase volumetric mass transfer coefficient is obtained.

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Airlift Reactors: Characteristics, Applications and Design Considerations

Cited by 261 publications

References 64 publications

Oxygen transfer and mixing in mechanically agitated airlift bioreactors

Oxygen transfer and mixing in mechanically agitated airlift bioreactors

The effects of geometry and operational conditions on gas holdup, liquid circulation and mass transfer in an airlift reactor

Liquid-Phase Volumetric Mass Transfer Coefficient for Dilute Alcohol Solution in an External-Loop Airlift Reactor with a Porous Plate (Effect of Pore Size of Porous Plate)

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