Influence of Spacing of Multiple Impellers on Power Input in an Industrial‐Scale Aerated Stirred Tank Reactor

Fitschen, Jürgen; Maly, Marc; Rosseburg, Annika; Wutz, Johannes; Wucherpfennig, Thomas; Schlüter, Michael

doi:10.1002/cite.201900121

Cited by 24 publications

(18 citation statements)

References 33 publications

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“…In respect to the described bubble formation behavior, the gas utility is compared at a k L a of 60 1/h and 160 1/h, resulting in applied vvm of 0.05 up to 0.67 for the sintered frit and 1 µm SPG aerator. In contrast to the microbubble aerators, higher gassing rates of 16.67 vvm (5 mm open pipe) and 8.44 vvm (6 × 0.5 mm open pipe) is necessary to achieve a k L a of 160 1/h, which would be uneconomic in process scale‐up (Fitschen et al, 2019; Garcia‐Ochoa & Gomez, 2009). Nevertheless, both macrobubble aerators are resulting in more reasonable flow rates at a k L a of 60 1/h with 2.23 vvm (5 mm open pipe) and 0.5 vvm (6 × 0.5 mm open pipe).…”

Section: Resultsmentioning

confidence: 99%

Comparative investigation of fine bubble and macrobubble aeration on gas utility and biotransformation productivity

Thomas

Ohde

Matthes

et al. 2020

Biotech & Bioengineering

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The sufficient provision of oxygen is mandatory for enzymatic oxidations in aqueous solution, however, in process optimization this still is a bottleneck that cannot be overcome with the established methods of macrobubble aeration. Providing higher mass transfer performance through microbubble aerators, inefficient aeration can be overcome or improved. Investigating the mass transport performance in a model protein solution, the microbubble aeration results in higher k L a values related to the applied airstream in comparison with macrobubble aeration. Comparing the aerators at identical k L a of 160 and 60 1/h, the microbubble aeration is resulting in 25 and 44 times enhanced gas utility compared with aeration with macrobubbles. To prove the feasibility of microbubbles in biocatalysis, the productivity of a glucose oxidase catalyzed biotransformation is compared with macrobubble aeration as well as the gas-saving potential. In contrast to the expectation that the same productivities are achieved at identically applied k L a, microbubble aeration increased the gluconic acid productivity by 32% and resulted in 41.6 times higher oxygen utilization. The observed advantages of microbubble aeration are based on the large volume-specific interfacial area combined with a prolonged residence time, which results in a high mass transfer performance, less enzyme deactivation by foam formation, and reduced gas consumption. This makes microbubble aerators favorable for application in biocatalysis.

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Section: Resultsmentioning

confidence: 99%

Comparative investigation of fine bubble and macrobubble aeration on gas utility and biotransformation productivity

Thomas

Ohde

Matthes

et al. 2020

Biotech & Bioengineering

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“…For the measurement of the power number, a motor (ViscoPaktRheo X7, HiTec Zang, Germany) with integrated torque sensor is used. A detailed description of the methodology and the data evaluation is given in [32].…”

Section: Methodsmentioning

confidence: 99%

Validation of Novel Lattice Boltzmann Large Eddy Simulations (LB LES) for Equipment Characterization in Biopharma

et al. 2021

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Detailed process and equipment knowledge is crucial for the successful production of biopharmaceuticals. An essential part is the characterization of equipment for which Computational Fluid Dynamics (CFD) is an important tool. While the steady, Reynolds-averaged Navier–Stokes (RANS) k − ε approach has been extensively reviewed in the literature and may be used for fast equipment characterization in terms of power number determination, transient schemes have to be further investigated and validated to gain more detailed insights into flow patterns because they are the method of choice for mixing time simulations. Due to the availability of commercial solvers, such as M-Star CFD, Lattice Boltzmann simulations have recently become popular in the industry, as they are easy to set up and require relatively low computing power. However, extensive validation studies for transient Lattice Boltzmann Large Eddy Simulations (LB LES) are still missing. In this study, transient LB LES were applied to simulate a 3 L bioreactor system. The results were compared to novel 4D particle tracking (4D PTV) experiments, which resolve the motion of thousands of passive tracer particles on their journey through the bioreactor. Steady simulations for the determination of the power number followed a structured workflow, including grid studies and rotating reference frame volume studies, resulting in high prediction accuracy with less than 11% deviation, compared to experimental data. Likewise, deviations for the transient simulations were less than 10% after computational demand was reduced as a result of prior grid studies. The time averaged flow fields from LB LES were in good accordance with the novel 4D PTV data. Moreover, 4D PTV data enabled the validation of transient flow structures by analyzing Lagrangian particle trajectories. This enables a more detailed determination of mixing times and mass transfer as well as local exposure times of local velocity and shear stress peaks. For the purpose of standardization of common industry CFD models, steady RANS simulations for the 3 L vessel were included in this study as well.

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“…With their adapted magnetic system, Suleiko et al ( 2020 ) demonstrated a drive with a torque of 200 Nm that is suitable for biological applications at a scale of 15 m 3 . ZETA’s magnetic bottom-mounted agitator for bioreactors with a torque of more than 400 Nm was also evaluated at the same scale (ZETA GmbH n.d. ; Rosseburg et al 2018 ; Fitschen et al 2019 ), delivering results that predict applicability at scales up to 30 m 3 (ZETA GmbH 2020a ). Although their initial industrial use was controversial because of biological (hygienic design and SIP/CIP capability), mechanical, and chemical safety (possible abrasion in bearing-based systems) concerns, as well as the early lack of speed and torque monitoring (Eibl et al 1996 ), magnetic agitators have been able to gain more and more acceptance, as a result of increased qualification and validation.…”

Section: Drive Systems and Seals Commonly Used In Biotechnological Prmentioning

confidence: 99%

An overview of drive systems and sealing types in stirred bioreactors used in biotechnological processes

Schirmer

Maschke

Pörtner

et al. 2021

Appl Microbiol Biotechnol

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No matter the scale, stirred tank bioreactors are the most commonly used systems in biotechnological production processes. Single-use and reusable systems are supplied by several manufacturers. The type, size, and number of impellers used in these systems have a significant influence on the characteristics and designs of bioreactors. Depending on the desired application, classic shaft-driven systems, bearing-mounted drives, or stirring elements that levitate freely in the vessel may be employed. In systems with drive shafts, process hygiene requirements also affect the type of seal used. For sensitive processes with high hygienic requirements, magnetic-driven stirring systems, which have been the focus of much research in recent years, are recommended. This review provides the reader with an overview of the most common agitation and seal types implemented in stirred bioreactor systems, highlights their advantages and disadvantages, and explains their possible fields of application. Special attention is paid to the development of magnetically driven agitators, which are widely used in reusable systems and are also becoming more and more important in their single-use counterparts.Key Points• Basic design of the most frequently used bioreactor type: the stirred tank bioreactor• Differences in most common seal types in stirred systems and fields of application• Comprehensive overview of commercially available bioreactor seal types• Increased use of magnetically driven agitation systems in single-use bioreactors

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Influence of Spacing of Multiple Impellers on Power Input in an Industrial‐Scale Aerated Stirred Tank Reactor

Cited by 24 publications

References 33 publications

Comparative investigation of fine bubble and macrobubble aeration on gas utility and biotransformation productivity

Comparative investigation of fine bubble and macrobubble aeration on gas utility and biotransformation productivity

Validation of Novel Lattice Boltzmann Large Eddy Simulations (LB LES) for Equipment Characterization in Biopharma

An overview of drive systems and sealing types in stirred bioreactors used in biotechnological processes

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