Gas‐holdup measurements in bubble columns using computed tomography

Kumar, Sailesh B.; Moslemian, D.; Duduković, Milorad P.

doi:10.1002/aic.690430605

Cited by 165 publications

(82 citation statements)

References 25 publications

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“…On the other hand, some works report that the column diam-eter affects the gas holdup. Botton et al [17] report that gas holdup increases when the column diameter decreases, whereas Kumar et al [18] who conducted experiments in bubble columns with diameters larger than 10 cm, state that there is a continuous increase in the gas holdup with increasing column diameter. To the best of our knowledge, there are no experimental results concerning bubble columns with diameter less than 10 cm, equipped with fine porous sparger.…”

Section: Gas Holdupmentioning

confidence: 99%

On the Design of Bubble Columns Equipped with a Fine Pore Sparger: Effect of Gas Properties

Ag¹,

Ti²,

Ap³

et al. 2018

Preprint

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Abstract:In our previous works we have proposed design equations that can predict with reasonable accuracy the transition point from homogeneous to heterogeneous regime as well as the gas holdup and the mean Sauter diameter at the homogeneous regime. The validity of the proposed correlations was checked with data obtained using different geometrical configurations and several Newtonian and non-Newtonian liquids as well as the addition of surfactants. However, in all the experiments the gas phase was atmospheric air. This work investigates the effect of gas phase properties by conducting experiments employing various gases (i.e., air, CO 2 , He) that cover a wide range of physical property values. Experiments revealed that only the use of low-density gas (He) has a measurable effect on bubble column performance. More precisely, when the low-density gas (He) is employed, the transition point shifts to higher gas flow rates and the gas holdup decreases, a fact attributed to the lower momentum force exerted by the gas. In view of the new data, the proposed correlations have been slightly modified to include the effect of gas phase properties and it is found that they can predict the aforementioned quantities with an accuracy of ±15%. It has been also proved that CFD simulations are an accurate means for assessing the flow characteristics inside a bubble column.

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Section: Gas Holdupmentioning

confidence: 99%

On the Design of Bubble Columns Equipped with a Fine Pore Sparger: Effect of Gas Properties

Ag¹,

Ti²,

Ap³

et al. 2018

Preprint

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“…Gopal and Sharma [12] found that L/D ratio, column diameter and distributor design have no significant effect on gas holdup, interfacial mass transfer area, and liquid-side mass transfer coefficient in low L/D bubble columns. Kumar et al [1] also found no effect of the static liquid height on the overall gas holdup while the local gas holdup increases with the axial distance from the distributor. Other researchers found a decrease in gas holdup with an increase in static liquid height [4,17,18].…”

Section: Introductionmentioning

confidence: 96%

“…Most traditional design of bubble column reactors favors a high height-to-diameter ratio (L/D) to allow system hydrodynamics to reach a fully developed state [1][2][3][4][5]. The gas distributor region is generally ignored in the scale-up considerations.…”

Section: Introductionmentioning

confidence: 99%

Mass transfer studies in shallow bubble column reactors

Lau

Lee

Chen

2012

Chemical Engineering and Processing: Process Intensification

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“…The shape of the gas holdup profile at different column heights seems to be unchanged at given gas velocity once the measurement has been taken at a certain distance from the distributor (2L/D or higher). Column diameter has been reported to have an effect on gas holdup profile (Kumar et al, 1997).…”

Section: Correlation Developmentmentioning

confidence: 99%

Advanced Diagnostic Techniques for Three-Phase Slurry Bubble Column Reactors (Sbcr)

Al-Dahhan¹,

Dudukovic²,

Fan³

2001

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This report summarizes the accomplishment made during the second year of this cooperative research effort between Washington University, Ohio State University and Air Products and Chemicals. The technical difficulties that were encountered in implementing Computer Automated Radioactive Particle Tracking (CARPT) in high pressure SBCR have been successfully resolved. New strategies for data acquisition and calibration procedure have been implemented. These have been performed as a part of other projects supported by Industrial Consortium and DOE via contract #DE-2295PC95051 which are executed in parallel with this grant. CARPT and Computed Tomography (CT) experiments have been performed using airwater-glass beads in 6" high pressure stainless steel slurry bubble column reactor at selected conditions. Data processing of this work is in progress. The overall gas holdup and the hydrodynamic parameters are measured by Laser Doppler Anemometry (LDA) in 2" slurry bubble column using Norpar 15 that mimic at room temperature the Fischer Tropsch wax at FT reaction conditions of high pressure and temperature. To improve the design and scale-up of bubble column, new correlations have been developed to predict the radial gas holdup and the time averaged axial liquid recirculation velocity profiles in bubble columns. iv ADVANCED DIAGNOSTIC TECHNIQUES FOR THREE-PHASE SLURRY BUBBLE COLUMN REACTORS (SBCR)Annual EXECUTIVE SUMMARYThe objective of this cooperative research effort between Washington University, Ohio State University and Air Products and Chemicals is to advance the understanding of the hydrodynamics of Fischer-Tropsch (FT) Slurry Bubble Column Reactors (SBCR) via advanced diagnostics techniques. The emphasis during this second year was: i) to implement the achieved solutions to the technical difficulties encountered during implementation of CARPT in high pressure SBCR and also to implement new achieved strategy, data acquisition and calibration procedure, ii) to perform CARPT and CT experiments using air-water-glass beads in 6" high pressure SBCR, iii) to perform LDA and overall gas holdup measurements in 2" slurry bubble column using Norpar 15 which mimics at room temperature FT wax at FT reaction conditions of high pressure and temperature, iv) to develop new correlations to predict the radial gas holdup and the time averaged axial liquid recirculation velocity profiles in bubble columns for improved design and scale up of bubble column reactors.This report summarizes the accomplishments made during the second year of this project. The report is organized in individual sections. Each section represents a distinct task.Section 1 provides an introduction and motivation for this collaborative project.Section 2 provides a review of the objectives and tasks set for the project, list of accomplishments during the first and second year and plan for the third year.Section 3 describes the experimental facilities and the advanced techniques like LDA, CARPT, CT used to study hydrodynamics of high pressure slurry b...

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Gas‐holdup measurements in bubble columns using computed tomography

Cited by 165 publications

References 25 publications

On the Design of Bubble Columns Equipped with a Fine Pore Sparger: Effect of Gas Properties

On the Design of Bubble Columns Equipped with a Fine Pore Sparger: Effect of Gas Properties

Mass transfer studies in shallow bubble column reactors

Advanced Diagnostic Techniques for Three-Phase Slurry Bubble Column Reactors (Sbcr)

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