Mass Transfer Studies in Stirred AirLift Reactor

Rostami, Khosrow; Wenge, Fu; Moo‐Young, Murray

doi:10.1080/00986440590473281

Cited by 7 publications

(1 citation statement)

References 36 publications

(17 reference statements)

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“…Chisti and Jauregui-Haza (2002) also found mechanically agitated airlift reactor to increase mixing performance and oxygen transfer although the oxygen transfer efficiency in terms of power consumption decreased compared to a regular airlift reactor. Rostami et al (2005) compared agitated draft tube reactor with airlift reactor and measured lower hold-up and kLa values for the agitated draft tube geometry. They also proposed different designs be tested in agitated draft tubes for air distribution as well as for agitation, such as utilizing radial flow impellers instead of axial flow impellers that were used in their study.…”

Section: Introductionmentioning

confidence: 99%

Mass transfer, gas hold-up and cell cultivation studies in a bottom agitated draft tube reactor and multiple impeller Rushton turbine configuration

Tervasmäki

Latva-Kokko

Taskila

et al. 2016

Chemical Engineering Science

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Gas-liquid mass transfer is an important phenomenon in aerobic microbial cultivations, and the mass transfer performance of an industrial reactor strongly affects the overall process economics. Traditionally, industrial and laboratory bioreactors have been agitated with flat disc turbines (Rushton turbines) although there are many variants to this design. In addition, pneumatically agitated reactors such as bubble columns and airlift reactors have been studied and used by the industry. In this study we utilize an agitated draft tube reactor in cell cultivation and mass transfer studies. A standard reactor geometry agitated with three Rushton turbines was compared to Outotec OKTOP®9000 reactor which is a draft tube reactor agitated with a single impeller located just below the draft tube. The experiments included cell cultivation with Pichia pastoris yeast, determination of overall mass transfer coefficient by dynamic gassing in method and measurement of local gas holdup by electrical impedance tomography (EIT). In addition, agitation power was estimated from the power consumption of the DC-motor. OKTOP®9000 reactor was found to have higher kLa values than the STR with similar agitation power and gas flowrate. The overall gas holdup was similar in both geometries at same power inputs and gas flow rates. However, some significant differences were detected in the distribution of gas phase between the two geometries especially in the axial direction. Also changes in the gas dispersion regime can be detected from the spatial distribution of the gas holdup measured by EIT. The cell cultivation experiments showed the applicability of this type of agitated draft tube reactor to bioprocesses although a direct comparison with Rushton geometry is not straightforward.

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Section: Introductionmentioning

confidence: 99%

Mass transfer, gas hold-up and cell cultivation studies in a bottom agitated draft tube reactor and multiple impeller Rushton turbine configuration

Tervasmäki

Latva-Kokko

Taskila

et al. 2016

Chemical Engineering Science

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Gas hold-up and oxygen mass transfer in three pneumatic bioreactors operating with sugarcane bagasse suspensions

Esperança

Cunha

Cerri

et al. 2013

Bioprocess Biosyst Eng

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Sugarcane bagasse is a low-cost and abundant by-product generated by the bioethanol industry, and is a potential substrate for cellulolytic enzyme production. The aim of this work was to evaluate the effects of air flow rate (QAIR), solids loading (%S), sugarcane bagasse type, and particle size on the gas hold-up (εG) and volumetric oxygen transfer coefficient (kLa) in three different pneumatic bioreactors, using response surface methodology. Concentric tube airlift (CTA), split-cylinder airlift (SCA), and bubble column (BC) bioreactor types were tested. QAIR and %S affected oxygen mass transfer positively and negatively, respectively, while sugarcane bagasse type and particle size (within the range studied) did not influence kLa. Using large particles of untreated sugarcane bagasse, the loop-type bioreactors (CTA and SCA) exhibited higher mass transfer, compared to the BC reactor. At higher %S, SCA presented a higher kLa value (0.0448 s−1) than CTA, and the best operational conditions in terms of oxygen mass transfer were achieved for %S < 10.0 g L−1 and QAIR > 27.0 L min−1. These results demonstrated that pneumatic bioreactors can provide elevated oxygen transfer in the presence of vegetal biomass, making them an excellent option for use in three-phase systems for cellulolytic enzyme production by filamentous fungi.

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Oxygen transfer in hydrocarbon–aqueous dispersions and its applicability to alkane bioprocesses: A review

Clarke

Correia

2008

Biochemical Engineering Journal

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Mass Transfer Studies in Stirred AirLift Reactor

Cited by 7 publications

References 36 publications

Mass transfer, gas hold-up and cell cultivation studies in a bottom agitated draft tube reactor and multiple impeller Rushton turbine configuration

Mass transfer, gas hold-up and cell cultivation studies in a bottom agitated draft tube reactor and multiple impeller Rushton turbine configuration

Gas hold-up and oxygen mass transfer in three pneumatic bioreactors operating with sugarcane bagasse suspensions

Oxygen transfer in hydrocarbon–aqueous dispersions and its applicability to alkane bioprocesses: A review

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