Experimental study and modeling on liquid dispersion in external-loop airlift slurry reactors

Liu, Malin; Zhang, Tongwang; Wang, Tiefeng; Wang, Yu; Wang, Jinfu

doi:10.1016/j.cej.2007.08.027

Cited by 24 publications

(15 citation statements)

References 23 publications

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“…Only in the regime III where a gas recirculation exists (Heijnen et al, 1997), the gas holdup both in the riser and the downcomer can be promoted with the increase of h tc (Kilonzo et al, 2006(Kilonzo et al, , 2007. This is why an increase of gas voidage was observed in IALR with the increase of top clearance (Chisti, 1989;Kilonzo et al, 2006Kilonzo et al, , 2007 and an opposite phenomenon is seen in this work and other publications (Lazarova et al, 1997;Liu et al, 2008;Lu et al, 1994).…”

Section: Hydrodynamicssupporting

confidence: 46%

“…Couvert et al (1999) argued that the top clearance has negligible effect on the gas holdup. Lazarova et al (1997), Liu et al (2008) and Lu et al (1994) stated that the gas voidage decreases with the increase of top clearance, while Chisti (1989), Kilonzo et al (2006) and Kilonzo et al (2007) drew a completely opposite conclusion. However, no further explanation has been made on it so far.…”

Section: Introductionmentioning

confidence: 94%

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Aeration and mass transfer optimization in a rectangular airlift loop photobioreactor for the production of microalgae

Guo

Yao

Huang

2015

Bioresource Technology

103

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Section: Hydrodynamicssupporting

confidence: 46%

Section: Introductionmentioning

confidence: 94%

Aeration and mass transfer optimization in a rectangular airlift loop photobioreactor for the production of microalgae

Guo

Yao

Huang

2015

Bioresource Technology

103

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“…The increase in gas flow rate resulted in the formation of a larger number of bubbles, which in return led to higher gas holdup. The same observation was reported previously by Yazdian et al , Liu et al , Mohanty et al and Han et al Fig. also shows that the gas holdup in the riser increased with decrease in the liquid static height in the bioreactor.…”

Section: Resultssupporting

confidence: 90%

“…also shows that the gas holdup in the riser increased with decrease in the liquid static height in the bioreactor. The effect of liquid height on gas holdup in the external recirculating airlift bioreactors was investigated previously by different researchers , . Apparently, with decreasing liquid height in the bioreactor, the flow resistance in the upper connecting tube is increased.…”

Section: Resultsmentioning

confidence: 97%

Dynamic and local gas holdup studies in external loop recirculating airlift reactor with two rolls of fiberglass packing using electrical resistance tomography

Hamood-Ur-Rehman

Ein‐Mozaffari

Dahman

2012

J of Chemical Tech & Biotech

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BACKGROUND: Airlift bioreactors have been used extensively in biotechnology industries in recent years in a variety of arrangements and applications. The insertion of packing inside the bioreactors has the potential to provide high productivity within a compact size through utilizing immobilized species. RESULTS: A novel recirculating external loop airlift bioreactor that has two rolls of fiberglass packing and a gas distributor in between was designed and built. Electrical resistance tomography (ERT) images showed that the gas holdup increased after installing the packing and the gas distributor. Gas holdup in the riser increased with decreasing static liquid height in the bioreactor. This decreased the liquid superficial velocity, which contributed to a higher gas holdup in the bioreactor. Results also showed that riser gas holdup varied slightly with different sparger configurations. Higher gas holdup increases the oxygen mass transfer rate by increasing the residence time and interfacial mass transfer area. CONCLUSION: ERT results showed that fiberglass packing with an installed gas distributor in bioreactors can achieve higher gas holdup at higher superficial gas velocity. This can contribute to improved conversion in bioreactors with packing through utilizing higher biomass concentrations and higher oxygen concentration. © 2012 Society of Chemical Industry

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“…A review of literature reveals that considerable work has been carried out on the measurement of external liquid circulations through a downcomer (Mohanty et al, 2006; Liu et al, 2008; Yazdian et al, 2009). However, the influence of axial liquid velocity profiles in the riser cannot be neglected mainly because it governs several key parameters in the design of ELAR, for example, gas–liquid effective interfacial area, rate of mass transfer, extent of liquid‐phase mixing and the rate of heat transfer at the wall.…”

Section: Introductionmentioning

confidence: 99%

Liquid circulation hydrodynamics in an external loop airlift reactor

Huang

Cheng

2011

Can J Chem Eng

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The radial profiles of axial liquid velocity and gas hold-ups are investigated in the riser of a pilot plant scale external loop airlift reactor (ELAR) using a modified Pavlov tube and differential pressure technique. The experimental investigation reveals that there exist two different kinds of liquid circulation structures in an ELAR, which has rarely been reported in the literature, namely internal liquid circulation, which exists only in the riser and external liquid circulation, which circulates through the downcomer. A power-law relationship is used to correlate the gas hold-up and superficial gas velocity, which gives good agreement with experimental data. Experiments for axial liquid velocity profiles are analysed in analogy to a model described for a conventional bubble column. The results predicted by the model are in excellent agreement with the experimental data obtained under various operating conditions.

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Experimental study and modeling on liquid dispersion in external-loop airlift slurry reactors

Cited by 24 publications

References 23 publications

Aeration and mass transfer optimization in a rectangular airlift loop photobioreactor for the production of microalgae

Aeration and mass transfer optimization in a rectangular airlift loop photobioreactor for the production of microalgae

Dynamic and local gas holdup studies in external loop recirculating airlift reactor with two rolls of fiberglass packing using electrical resistance tomography

Liquid circulation hydrodynamics in an external loop airlift reactor

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