Quantitative measurement of gas hold-up distribution in a stirred chemical reactor using X-ray cone-beam computed tomography

Boden, Stephan; Bieberle, Martina; Hampel, Uwe

doi:10.1016/j.cej.2007.08.014

Cited by 43 publications

(20 citation statements)

References 41 publications

(43 reference statements)

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“…They concluded that bubbles formed a distribution such that the larger bubbles were in a region outside the impeller sh·eam and were up to four times larger than the bubbles entrai ned in the impeller stream. More specifically, gas in these setups would concentrate about the impeller shaft, impeller tip, and within the radial area between the impeller and reactor walls [29,41]. These observations were made for an axial system, but are very similar to those made by Stenberg and Andersson [35] for a single Rushtontype turbine (1 RT) setup, which produced a similar qualitative mass transfer behavior for these impeller types.…”

Section: Figure 2: Effects Of Multiple Impellers On Gas-liquid Mass Tsupporting

confidence: 61%

Mixing Considerations in Stirred Tank Bioreactors When Using Fluid Property Altering Microorganisms

Kadic

Heindel

2010

ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting: Volume 1, Symposia – Parts A, B, and C

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Stirred tank reactors are one of the standard reactors in the chemical industry and have been widely implemented for biological applications. They are used with viscous liquids, slurries, very low gas flow rates, and large liquid volumes. Stirred tank bioreactors are popular because a well-mixed state, required or preferred for numerous biological processes, is usually achieved in such situations; however, many production processes using microorganisms tend to experience fluid property alterations, which significantly impact mixing, operational parameters, and process results. The most troubling issues occur when a fluid gradually undergoes a viscosity change and/or slowly exhibits non-Newtonian behavior due to microorganism growth since these will alter the flow conditions and possibly limit the conversion rate or production scale. This paper provides an overview of the relevant mixing issues in stirred tank bioreactors when using a range of fluid viscosities, surface tensions, and/or non-Newtonian fluids. ABSTRACT Stirred tank reactors are one of the standard reactors in the chemical industry and have been widely implemented for biological applications. They are used with viscous liquids, lurries, very low gas flow rates, and large liquid vo lumes. tirred tank bioreactors are popular because a well-mixed state, required or prefetTed for numerous biological processes, is usually achieved in such situations; however, many production processes using microorganisms tend to experience fluid property alterations, which significantly impact mixing, operational parameters, and process results. The most troubling i ues occur when a fluid gradually undergoes a viscosity change and/or slowly exhibits non-Newtonian behavior due to microorganism growth since these will alter the flow conditions and possibly limit the conversion rate or production sca le. This paper provides an overview of the relevant mixing issues in tirred tank bioreactors when using a range of fluid viscosities, urface tensions, and/or non-Newtonian fluids .

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Section: Figure 2: Effects Of Multiple Impellers On Gas-liquid Mass Tsupporting

confidence: 61%

Mixing Considerations in Stirred Tank Bioreactors When Using Fluid Property Altering Microorganisms

Kadic

Heindel

2010

ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting: Volume 1, Symposia – Parts A, B, and C

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“…The resulting image cube is of 750 × 750 × 500 pixels size with voxels of 70 lm edge length. A detailed description of the system and measurement procedure as well as the data processing can be found elsewhere [48,49]. Fig.…”

Section: X-ray Microtomographymentioning

confidence: 99%

Advanced Tomographic Techniques for Flow Imaging in Columns with Flow Distribution Packings

Schubert

Bieberle

Barthel

et al. 2011

Chemie Ingenieur Technik

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Design and optimization of separation units, e.g., distillation and absorption columns with flow distribution packings, require detailed knowledge about the internal flow conditions and their impact on the process behavior. This in turn calls for suitable measuring techniques, which can give a detailed insight into such devices, especially for studies on a laboratory and pilot scale. Traditional instrumentation, such as compartment-type liquid collectors installed below packings, or distributed temperature, pressure and conductivity probes, often falls too short if detailed knowledge on flow conditions is required. This concerns especially local liquid holdup, liquid maldistribution, liquid films thickness, wetting of the packing surface, or bubble size and droplet distribution at trays. Advanced imaging techniques, such as tomography, have found only marginal attention in investigations of separation columns with structured and modern dumped flow distribution packings, mostly due to limited spatial and temporal resolution but also due to prevailing technological problems encountered in such applications. In this study, the potentials and limits of some of the most recently emerged tomographic imaging modalities for multiphase flows have been investigated and reviewed, i.e., ultra-fast X-ray tomography, high-resolution gamma-ray tomography, wire-mesh sensor techniques, and X-ray microtomography with respect to a possible application in separation columns with flow distribution packings.

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“…The high resolution images show the liquid accumulation regions in the packing material. Further Boden et al (2008) could get 3D images by using X-ray tomography, in which the single voxel size was as low as 200 mm. In other cases the resolution of few millimeters is common (Azzi et al, 1991;Roy et al, 2004;Yin et al, 2002).…”

Section: Liquid Distribution In Packed Columnmentioning

confidence: 99%

Some industrial applications of gamma-ray tomography

Kalaga

Kulkarni

Acharya

et al. 2009

Journal of the Taiwan Institute of Chemical Engineers

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Quantitative measurement of gas hold-up distribution in a stirred chemical reactor using X-ray cone-beam computed tomography

Cited by 43 publications

References 41 publications

Mixing Considerations in Stirred Tank Bioreactors When Using Fluid Property Altering Microorganisms

Mixing Considerations in Stirred Tank Bioreactors When Using Fluid Property Altering Microorganisms

Advanced Tomographic Techniques for Flow Imaging in Columns with Flow Distribution Packings

Some industrial applications of gamma-ray tomography

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