Breakage of drops and bubbles in a stirred tank: A review of experimental studies

Hasan, Basim O.

doi:10.1016/j.cjche.2017.03.008

Cited by 22 publications

(13 citation statements)

References 67 publications

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“…Several methods to calculate d 32 are available. 21 Those based on image analysis are convenient. 22 These methods require the capture of high-speed bubble images which are subsequently counted.…”

Section: Fundamentals Of Oxygen Transfer and Air Bubble Dispersionmentioning

confidence: 99%

Oxygen transfer and bubble sizes occurring in a pilot‐scale cultivation of Bacillus velezensis 83 for the production of poly(γ‐glutamic acid) under two schemes of power drawn

Pulido‐Durán

Flores

Serrano‐Carreón

et al. 2022

J of Chemical Tech & Biotech

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BACKGROUND The influence of power consumption on oxygen transfer during non‐Newtonian and surfactant‐producing microbial fermentations has been scarcely reported. In this work, we study the oxygen transfer and bubble size distributions in a real 100 L fermentation (producing poly(γ‐glutamic acid)) occurring under constant stirring speed (N) and under constant retrofitted power drawn (Pg/V). RESULTS For constant N fermentations, Pg/V and the volumetric mass transfer coefficient (kLa) decreased 40% and 70% during cultivation, respectively. Fermentations at constant Pg/V showed a decrease similar to that observed for constant N fermentations. Bubble size distributions were also similar for both operational conditions. Although an increase in bubble size was expected at constant N cultivations due to the increasing viscosity of the medium, the Sauter mean diameter (d32) decreased 65%. This singular behavior of d32 was likely caused by surfactin and bacillomycin, metabolites with strong surfactant activity produced by Bacillus velezensis 83 in the cultivations. The use of a constant Pg/V did not counteract the decrease in kLa due to the increase in viscosity. Although the presence of biosurfactants leads to an increase of interfacial transfer area by decreasing d32, the presence of these molecules and the increase in the medium viscosity affected kLa. CONCLUSIONS An atypical behavior of this system was found, especially in d32, different to that based on common correlations found in the literature. A complex interaction among the multiple factors involved in a real bioprocess for poly(γ‐glutamic acid) production was evidenced. © 2022 Society of Chemical Industry (SCI).

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Section: Fundamentals Of Oxygen Transfer and Air Bubble Dispersionmentioning

confidence: 99%

Oxygen transfer and bubble sizes occurring in a pilot‐scale cultivation of Bacillus velezensis 83 for the production of poly(γ‐glutamic acid) under two schemes of power drawn

Pulido‐Durán

Flores

Serrano‐Carreón

et al. 2022

J of Chemical Tech & Biotech

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“…In order to correlate the hydrodynamic and process conditions with the suspension or dispersion properties especially the change in the species concentration-spatial and temporal evolution of the particle size distribution, a number of laboratory measurement techniques are widely adopted [25]. The choice will depend to a large extent on the concentration and size distribution of the disperse phase and the nature of the flow.…”

Section: Experimental Analysis Of Physicochemical Processesmentioning

confidence: 99%

Hydrodynamic Characterization of Physicochemical Process in Stirred Tanks and Agglomeration Reactors

Oyegbile¹,

Akdogan²

2018

Laboratory Unit Operations and Experimental Methods in Chemical Engineering

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A short review of the state of the art in experimental and computational fluid dynamics (CFD) characterization of micro-hydrodynamics and physicochemical processes in stirred tanks and agglomeration reactors is presented. Results of experimental and computational studies focusing on classical mixing tanks as well as other innovative reactors with various industrial applications are briefly reviewed. The hydrodynamic characterization techniques as well as the influence of the fluid dynamics on the efficiency of the physicochemical processes have been highlighted including some of the limitations of the reported modeling approach and solution strategy. Finally, the need for specialized CFD codes tailored to the specific needs of fluid-particle reactor design and optimization is advocated to advance research in this field.

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“…The daughter size distribution predicts the most probable droplet sizes following a breakage event. Attempts for obtaining this information from real or numerical experiments have been described in the literature [8][9][10][11][12][13], but despite the best efforts, the procedure is very complex and time consuming. The main reason for such difficulties stems from the number of breakup events to be detected to reach statistical significance for every initial mother size and fluid dynamic condition, since by varying these two factors the breakage event may lead to very different outcomes.…”

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Analysis of the Daughter Distribution in Liquid‐Liquid Stirred Tanks

et al. 2021

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The drop size distributions (DSDs) of a dilute immiscible liquid-liquid mixture were measured in a fully turbulent stirred tank operating at different impeller speeds. The results were used to infer the best daughter distribution function (DDF) leading to the best reproduction of the shape of the DSD. Bell-shaped, U-shaped, M-shaped, and uniform statistical DDFs were studied, producing from two to four daughters from each breakup event. A simplified approach from the literature was adopted to solve the population balance equation that considers the spectrum of the turbulence inside the tank obtained from computational fluid dynamics simulations. The U-shaped distribution producing four fragments better reproduces the shape of the experimental DSD in the studied system.

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Breakage of drops and bubbles in a stirred tank: A review of experimental studies

Cited by 22 publications

References 67 publications

Oxygen transfer and bubble sizes occurring in a pilot‐scale cultivation of Bacillus velezensis 83 for the production of poly(γ‐glutamic acid) under two schemes of power drawn

Oxygen transfer and bubble sizes occurring in a pilot‐scale cultivation of Bacillus velezensis 83 for the production of poly(γ‐glutamic acid) under two schemes of power drawn

Hydrodynamic Characterization of Physicochemical Process in Stirred Tanks and Agglomeration Reactors

Numerical and Experimental Analysis of the Daughter Distribution in Liquid‐Liquid Stirred Tanks

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