An airlift reactor with double net draft tubes and its application in fermentation

Tung, Hung-Ping; Chiou, Shiaw-Yuh; Tu, C.-C.; Wu, Wen‐Teng

doi:10.1007/s004490050344

Cited by 24 publications

(11 citation statements)

References 19 publications

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“…The gas hold-up values obtained in this work were similar to those reported by Tung et al [16] and Wu and Wu [17], who used airlift reactors with net tubes, and higher than those estimated for other reactor types, such as in concentric tube airlift reactors [2,9,10,14] and in a rectangular airlift reactor [8], for similar super®cial gas velocities. Figure 7 shows the variation of the overall volumetric oxygen transfer coef®cient in the reactor, as a function of the super®cial air velocity for three liquid heights (120, 240, and 420 mm).…”

Section: Overall Gas Hold-up ()supporting

confidence: 89%

“…The mixing time values obtained in the proposed reactor are lower than those reported for a bubble column, an airlift bioreactor which contains two separable concentric tubes with a mesh number of 3 [16], a split-channel airlift reactor with different con®gurations of the head region [5], a bubble column with a membrane sparger, a bubble column with a membrane and a ring sparger, an internal loop airlift reactor with a membrane sparger [11], and for a concentric tube airlift bioreactor [14]. All of them were compared for equivalent super®cial gas velocities.…”

Section: Mixing Timecontrasting

confidence: 77%

“…Among the most relevant proposals are those of Hagino et al [7], using a bubble column with draft device comprising a series of coaxially disposed curved plates, Wu and Wu [17,18], and Tung et al [16] using airlift reactors with one or two net draft tubes.…”

Section: List Of Symbolsmentioning

confidence: 99%

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A novel split-cylinder airlift reactor for fed-batch cultures

Galíndez‐Mayer¹,

Sanchez-Teja²,

Cristiani‐Urbina³

et al. 2001

Bioprocess and Biosystems Engineering

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Conventional airlift reactors are not adequate to carry out variable volume processes since it is not possible to achieve a proper liquid circulation in these reactors until the liquid height is higher than that of the downcomer. To carry out processes of variable volume, the use of a split-cylinder airlift reactor is proposed, in the interior of which two multi-perforated vertical baf¯es are installed in order to provide several points of communication between the reactor riser and downcomer. This improves the liquid circulation and mixing at any liquid volume.In fed-batch cultures, it is important to know how liquid height affects the hydrodynamic characteristics and the volumetric oxygen transfer coef®cient since this impacts on the kinetic behavior of any fermentation. Thus, in the present work, the effect of the liquid height on the mixing time, the overall gas hold-up, and the volumetric oxygen transfer coef®cient of the proposed airlift reactor were determined.The mixing time was increased and the volumetric oxygen transfer coef®cient decreased due to the increase of the liquid height in the reactor in all the super®cial gas velocities tested, which corresponded to a pseudohomogeneous¯ow regime. The experimental values of the mixing time and the mass-transfer coef®cient were properly described through correlations in which the U GR /H L ratio was used as the independent variable. Thus, this variable might be used to describe the hydrodynamic behavior and the oxygen transfer coef®cient of airlift reactors when such reactors are used in processes where the liquid volume changes with time.However, these correlations are useful for the particular device and for the particular operating conditions at which they were obtained. These empirical correlations are useful to understand some factors that in¯uence the mixing time and volumetric oxygen transfer coef®cient, but such correlations do not have a suf®cient predictive potential for a satisfactory reactor design.The overall gas hold-up values were not signi®cantly affected when the liquid height was lower than the downcomer height. However, the values decreased abruptly when the reactor was operated with liquid heights over the downcomer height, especially at high super®cial gas velocities.

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Section: Overall Gas Hold-up ()supporting

confidence: 89%

Section: Mixing Timecontrasting

confidence: 77%

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A novel split-cylinder airlift reactor for fed-batch cultures

Galíndez‐Mayer¹,

Sanchez-Teja²,

Cristiani‐Urbina³

et al. 2001

Bioprocess and Biosystems Engineering

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“…As a result, when the proposed reactor was used with a fed-batch culture of Saccharomyces cerevisiae, an increase in cell mass was obtained compared with a fed-batch culture at the same operating conditions in the original air-lift or bubble reactors. Tung et al 45 further modified the air-lift reactor by adding two concentric wire-mesh draft tubes with a sparger located between the tubes. The draft tubes had a significant effect on breaking bubbles into smaller ones.…”

Section: Effect Of the Type Of Reactor On Productionmentioning

confidence: 99%

Improvements in the production of bacterial synthesized biocellulose nanofibres using different culture methods

Sani

Dahman

2009

J of Chemical Tech & Biotech

112

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This review summarizes previous work that was done to improve the production of bacterial cellulose nanofibres. Production of biocellulose nanofibres is a subject of interest owing to the wide range of unique properties that makes this product an attractive material for many applications. Bacterial cellulose is a natural nanomaterial that has a native dimension of less than 50 nm in diameter. It is produced in the form of nanofibres, yielding a very pure cellulose product with unique physical properties that distinguish it from plant-derived cellulose. Its high surface-to-volume ratio combined with its unique properties such as poly-functionality, hydrophilicity and biocompatibility makes it a potential material for applications in the biomedical field. The purpose of this review is to summarize the methods that might help in delivering microbial cellulose to the market at a competitive cost. Different feedstocks in addition to different bioreactor systems that have been previously used are reviewed. The main challenge that exists is the low yield of the cellulosic nanofibres, which can be produced in static and agitated cultures. The static culture method has been used for many years. However, the production cost of this nanomaterial in bioreactor systems is less expensive than the static culture method. Biosynthesis in bioreactors will also be less labour intensive when scaled up. This would improve developing intermediate fermentation scale-up so that the conversion to an efficient large-scale fermentation technology will be an easy task.

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“…Tung et al [8] proposed an airlift reactor with double net draft tubes in a laboratory scale and applied it to cultivation of baker's yeast. In the present study, a pilot scale airlift reactor with four modules of double net draft tubes was developed.…”

mentioning

confidence: 99%

Bubble characteristics and mass transfer in an airlift reactor with multiple net draft tubes

Tung

Chang

et al. 1998

Bioprocess Engineering

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A pilot scale airlift reactor with multiple net draft tubes was developed. The reactor, 29 cm in diameter and 300 cm height, had four modules of double net draft tubes. Bubble size, bubble number, gas holdup, and volumetric mass transfer coef®cient were measured under different super®cial air velocities. The air velocity had little effect on bubble size but had signi®cant in¯uence on bubble number. A bubble column was also investigated for comparison. The airlift reactor had a higher gas holdup and volumetric mass transfer coef®cient than those in the bubble column. The draft tubes in the airlift reactor substantially improved the reactor performance.

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An airlift reactor with double net draft tubes and its application in fermentation

Cited by 24 publications

References 19 publications

A novel split-cylinder airlift reactor for fed-batch cultures

A novel split-cylinder airlift reactor for fed-batch cultures

Improvements in the production of bacterial synthesized biocellulose nanofibres using different culture methods

Bubble characteristics and mass transfer in an airlift reactor with multiple net draft tubes

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