Oxygen mass transfer and hydrodynamics in a multi-phase airlift bioscrubber system

Littlejohns, Jennifer V.

doi:10.1016/j.ces.2009.06.058

Cited by 12 publications

(5 citation statements)

References 33 publications

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“…The dashed curves correspond to water as reference and were calculated with the model proposed below. It can be seen that k L a decreased with increasing solid holdup, a trend previously reported for airlift and fluidized‐bed reactors 16, 30–32. The same effect was found for the smaller particles used ( d S = 0.9 mm).…”

Section: Resultssupporting

confidence: 83%

“…The results in Fig. 2 were in the same range as those reported with airlift systems 16–19 and higher than those measured in a spout‐fluidized bed of 1.75‐mm glass beads working at minimum spout‐fluidized velocity 20. Nevertheless, comparing the operational boundary conditions regarding the aeration in the DTSB ( r Q = 1.0 and 0.0), the full transfer of air flow from the spout to the annulus enhanced the oxygen transfer rate between four and five times, with a maximum at about S = 1.0 min −1 .…”

Section: Resultssupporting

confidence: 76%

“…These results suggest that the hydrodynamic characteristics of solid particles (mainly particle size, buoyant density, and terminal velocity) play a significant role in the oxygen transfer rate to the liquid phase in the DTSB. On the other hand, decreases in k L a have been reported in systems containing particles with high affinity for oxygen, such as silicone rubber 16. To explore this possibility in our system, additional experiments were performed by adding loads of CDP beads ( ϵ S ≤ 22 %) to oxygen‐saturated water, but no significant differences in DO concentration were observed.…”

Section: Resultsmentioning

confidence: 93%

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Characterization and Modeling of Oxygen Transfer in a Spouted‐Bed Reactor with Auxiliary Aeration

Peñas

Safont

2016

Chem Eng & Technol

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A draft-tube spouted-bed (DTSB) reactor was equipped with an auxiliary aeration device to provide air into the annular region and thereby improve the oxygen transfer efficiency. The effects of the total air flow rate and its distribution between spout and annulus, the liquid phase viscosity (water and carboxymethyl cellulose solutions), and the solid holdup (glass and cyclodextrin polymer beads) on the oxygen transfer efficiency were discussed. The oxygen transfer coefficient increased with the air flow rate and the ratio of air flowing through the annulus, whereas it decreased with increasing viscosity and solid holdup. A correlation was proposed to predict the transfer coefficient in DTSB reactors with primary and auxiliary aeration. A good fitting was achieved between the experimental data and those estimated with the model.

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Section: Resultssupporting

confidence: 83%

Section: Resultssupporting

confidence: 76%

Section: Resultsmentioning

confidence: 93%

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Characterization and Modeling of Oxygen Transfer in a Spouted‐Bed Reactor with Auxiliary Aeration

Peñas

Safont

2016

Chem Eng & Technol

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“…However, the cells in the TPPB transformation at 400 rpm still displayed branched‐rich filaments, a morphology of this strain itself in liquid culture, and there were no any ndications of the destructive effects of strong shear force on cells as had been seen in the single phase bioreactor configuration (data not shown). The incorporation of the polymer beads in the bioreactor may decrease or buffer the destructive effects of strong shear force on the cells, which is significant for the performance of such strains …”

Section: Resultsmentioning

confidence: 99%

Transformation of ferulic acid to vanillin using a fed‐batch solid–liquid two‐phase partitioning bioreactor

2013

Biotechnology Progress

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Amycolatopsis sp. ATCC 39116 (formerly Streptomyces setonii) has shown promising results in converting ferulic acid (trans-4-hydroxy-3-methoxycinnamic acid; substrate), which can be derived from natural plant wastes, to vanillin (4-hydroxy-3-methoxybenzaldehyde). After exploring the influence of adding vanillin at different times during the growth cycle on cell growth and transformation performance of this strain and demonstrating the inhibitory effect of vanillin, a solid-liquid two-phase partitioning bioreactor (TPPB) system was used as an in situ product removal technique to enhance transformation productivity by this strain. The thermoplastic polymer Hytrel(®) G4078W was found to have superior partitioning capacity for vanillin with a partition coefficient of 12 and a low affinity for the substrate. A 3-L working volume solid-liquid fed-batch TPPB mode, using 300 g Hytrel G4078W as the sequestering phase, produced a final vanillin concentration of 19.5 g/L. The overall productivity of this reactor system was 450 mg/L. h, among the highest reported in literature. Vanillin was easily and quantitatively recovered from the polymers mostly by single stage extraction into methanol or other organic solvents used in food industry, simultaneously regenerating polymer beads for reuse. A polymer-liquid two phase bioreactor was again confirmed to easily outperform single phase systems that feature inhibitory or easily further degraded substrates/products. This enhancement strategy might reasonably be expected in the production of other flavor and fragrance compounds obtained by biotransformations.

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“…However, sufficient mass transfer from the gas phase is a concern for both tank configurations due to low solubility of oxygen and potential low solubility of VOCs in water, and oxygen mass transfer of airlift reactors is often slower than in stirred tanks agitated above 400 rpm. 1,2 Recently, Littlejohns and Daugulis 3 investigated an airlift system for the treatment of benzene, toluene, ethylbenzene and o-xylene (BTEX) that contained a second suspended phase of solid silicone rubber beads (10% v/v) with a high affinity for BTEX, called the airlift solid-liquid two-phase partitioning bioreactor (SL-TPPB). The silicone rubber beads served to uptake excess BTEX from the cell containing aqueous phase during increased loading fluctuations which was released back to the aqueous phase according to metabolic demand and maintaining equilibrium conditions.…”

Section: Introductionmentioning

confidence: 99%

Model for a solid‐liquid airlift two‐phase partitioning bioscrubber for the treatment of BTEX

Littlejohns

McAuley

2009

J of Chemical Tech & Biotech

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BACKGROUND: Airlift solid-liquid two-phase partitioning bioreactors (SL-TPPBs) have been shown to be effective for the treatment of gas streams containing benzene, toluene, ethylbenzene and o-xylene (BTEX). The airlift SL-TPPB is a low-energy system that utilizes a sequestering phase of solid silicone rubber beads (10%v/v) that will uptake and release large amounts of BTEX in order to maintain equilibrium conditions within the system. This increases mass transfer from the gas phase during dynamic loading periods and improves degradation performance. This study discusses the development and analysis of a steady-state, tanks-in-series mathematical model, arising from mass balances on BTEX and oxygen in the gas, aqueous and polymer phases to predict the performance of the airlift SL-TPPB over various gas flow rates and BTEX loadings.

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Oxygen mass transfer and hydrodynamics in a multi-phase airlift bioscrubber system

Cited by 12 publications

References 33 publications

Characterization and Modeling of Oxygen Transfer in a Spouted‐Bed Reactor with Auxiliary Aeration

Characterization and Modeling of Oxygen Transfer in a Spouted‐Bed Reactor with Auxiliary Aeration

Transformation of ferulic acid to vanillin using a fed‐batch solid–liquid two‐phase partitioning bioreactor

Model for a solid‐liquid airlift two‐phase partitioning bioscrubber for the treatment of BTEX

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