Bubble columns with fine pore sparger and non-Newtonian liquid phase: Prediction of gas holdup

Anastasiou, Antonios D.; Passos, A.D.; Mouza, A.A.

doi:10.1016/j.ces.2013.05.006

Cited by 58 publications

(30 citation statements)

References 21 publications

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“…Three effects simultaneously play a role in gas holdup, leading to the increase of gas holdup with increasing SDS concentration. This conclusion is consistent with previously reported results [8,23].…”

Section: Materialsupporting

confidence: 83%

Effect of Surfactants on Gas Holdup in Shear-Thinning Fluids

Huang

Fan

2017

International Journal of Chemical Engineering

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In this study, the gas holdup of bubble swarms in shear-thinning fluids was experimentally studied at superficial gas velocities ranging from 0.001 to 0.02 m⋅s −1 . Carboxylmethyl cellulose (CMC) solutions of 0.2 wt%, 0.6 wt%, and 1.0 wt% with sodium dodecyl sulfate (SDS) as the surfactant were used as the power-law (liquid phase), and nitrogen was used as the gas phase. Effects of SDS concentration, rheological behavior, and physical properties of the liquid phase and superficial gas velocity on gas holdup were investigated. Results indicated that gas holdup increases with increasing superficial gas velocity and decreasing CMC concentration. Moreover, the addition of SDS in CMC solutions increased gas holdup, and the degree increased with the surfactant concentration. An empirical correlation was proposed for evaluating gas holdup as a function of liquid surface tension, density, effective viscosity, rheological property, superficial gas velocity, and geometric characteristics of bubble columns using the experimental data obtained for the different superficial gas velocities and CMC solution concentrations with different surfactant solutions. These proposed correlations reasonably fitted the experimental data obtained for gas holdup in this system.

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Section: Materialsupporting

confidence: 83%

Effect of Surfactants on Gas Holdup in Shear-Thinning Fluids

Huang

Fan

2017

International Journal of Chemical Engineering

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“…However, it was decided to adopt the higher mesh size, because it provided greater refinement in significant regions, improving local values and enhancing the global results. Local refinement in the sparger and gas-liquid interface regions is necessary and has been recommended previously [8,35].…”

Section: Auxiliary Resultsmentioning

confidence: 99%

“…The global gas holdup ( a G ) is one of the key performance parameters, because it defines the specific interfacial area of the bubbles, an essential consideration in processes involving oxygen transfer [8]. Chen et al [9] evaluated the profile of the gas volume fraction in a bubble column bioreactor using computed tomography techniques.…”

Section: Introductionmentioning

confidence: 99%

Global performance parameters for different pneumatic bioreactors operating with water and glycerol solution: experimental data and CFD simulation

Rodriguez

Valverde-Ramírez

Mendes

et al. 2015

Bioprocess Biosyst Eng

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Global variables play a key role in evaluation of the performance of pneumatic bioreactors and provide criteria to assist in system selection and design. The purpose of this work was to use experimental data and computational fluid dynamics (CFD) simulations to determine the global performance parameters gas holdup ([Formula: see text]) and volumetric oxygen transfer coefficient (k L a), and conduct an analysis of liquid circulation velocity, for three different geometries of pneumatic bioreactors: bubble column, concentric-tube airlift, and split tube airlift. All the systems had 5 L working volumes and two Newtonian fluids of different viscosities were used in the experiments: distilled water and 10 cP glycerol solution. Considering the high oxygen demand in certain types of aerobic fermentations, the assays were carried out at high flow rates. In the present study, the performances of three pneumatic bioreactors with different geometries and operating with two different Newtonian fluids were compared. A new CFD modeling procedure was implemented, and the simulation results were compared with the experimental data. The findings indicated that the concentric-tube airlift design was the best choice in terms of both gas holdup and volumetric oxygen transfer coefficient. The CFD results for gas holdup were consistent with the experimental data, and indicated that k L a was strongly influenced by bubble diameter and shape.

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“…Generally, gas spargers with a hole diameter, d 0 , smaller than 1 mm (the "fine distributors", i.e., porous [32,33,38,39], membrane [40], needles [13,14,41] or sieve tray/perforated plates with small openings [37] see Figure 5 for a representation of these gas spargers) can maintain a stable mono-dispersed homogenous flow regime also at a high U G ; hence, the homogeneous flow regime is stabilized [13] because the "mono-dispersed homogeneous" flow regime exists [37] and the "pseudo-homogeneous" flow regime takes place after the former is destabilized. In contrast, using a "coarse gas sparger" (d 0 > 1 mm-see Figure 6 for a representation of these gas spargers) the "mono-dispersed homogeneous" flow regime may not exist and a "pseudo-homogeneous" flow regime may be observed at lower gas superficial velocities; finally, when using a "very coarse gas sparger" (d 0 >> 1 mm), the homogeneous flow regime may not be established and the transitional/heterogeneous flow regime may take place [42].…”

Section: Gas Sparger Designmentioning

confidence: 99%

Two-Phase Bubble Columns: A Comprehensive Review

2018

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We present a comprehensive literature review on the two-phase bubble column; in this review we deeply analyze the flow regimes, the flow regime transitions, the local and global fluid dynamics parameters, and the mass transfer phenomena. First, we discuss the flow regimes, the flow regime transitions, the local and global fluid dynamics parameters, and the mass transfer. We also discuss how the operating parameters (i.e., pressure, temperature, and gas and liquid flow rates), the operating modes (i.e., the co-current, the counter-current and the batch modes), the liquid and gas phase properties, and the design parameters (i.e., gas sparger design, column diameter and aspect ratio) influence the flow regime transitions and the fluid dynamics parameters. Secondly, we present the experimental techniques for studying the global and local fluid dynamic properties. Finally, we present the modeling approaches to study the global and local bubble column fluid dynamics, and we outline the major issues to be solved in future studies.

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Bubble columns with fine pore sparger and non-Newtonian liquid phase: Prediction of gas holdup

Cited by 58 publications

References 21 publications

Effect of Surfactants on Gas Holdup in Shear-Thinning Fluids

Effect of Surfactants on Gas Holdup in Shear-Thinning Fluids

Global performance parameters for different pneumatic bioreactors operating with water and glycerol solution: experimental data and CFD simulation

Two-Phase Bubble Columns: A Comprehensive Review

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