Stirred-tank mechanical power requirement and gas holdup in aerated aqueous phases
TL;DR: In this paper, the authors measured gas holdup and the ratio of the turbulent regime mechanical power consumed in aerated compared to that in nonaerated aqueous phases were measured in two laboratory sized tanks.
Abstract: Gas holdup and the ratio of the turbulent regime mechanical power consumed in aerated compared to that in nonaerated aqueous phases were measured in two laboratory sized tanks. Standard six-blade turbine (D/T = 1/3), six-blade paddle (D/T = 1/3), and four-blade paddle (D/T = 2/3) impellers were used over a wide range of impeller rotational speed and gas sparging rate. For all systems, the power ratio results were found to fit a semitheoretical correlation (derived from dimensional analysis) involving the impeller Weber number, the aeration number, and the ratio of dispersion and liquid densities. Empirical correlations for gas holdup in water, aqueous solutions of nonelectrolytes, and an aqueous electrolyte solution are given. The overall results lead to the conclusion that power ratio and gas holdup correlations are highly specific to a particular impeller type and are also dependent on the tank size and the liquid phase physicochemical properties.
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TL;DR: In this article, experimentale de quatre contacteurs a boucle externe, dont le rapport des sections du trop plein et du tube de montee se situe dans le domaine 0,11≤A d /A r ≤ 0,69 and de trois contacteur a tubes concentriques, cet.
Abstract: Etude experimentale de quatre contacteurs a boucle externe, dont le rapport des sections du trop plein et du tube de montee se situe dans le domaine 0,11≤A d /A r ≤0,69 et de trois contacteurs a tubes concentriques, ce rapport se situant dans la gamme 0,13≤A d /A r ≤0,56. Resultats concernant la vitesse du liquide dans la colonne de montee, le nombre de Bodenstein de la phase liquide et le temps de melange
166 citations
TL;DR: In this article, the effects of process variables on the volumetric liquid phase mass transfer coefficient of oxygen, k L a, in a stirred bioreactor were investigated by the static gassing-out method.
156 citations
TL;DR: In this paper, a multiblock stirred tank model with population balances for bubbles was created to describe local bubble size distributions (BSDs) from Rushton turbine agitated (14/200 L) air-tap water and CO 2 -n -butanol dispersions.
143 citations
01 Jan 1981
TL;DR: In this paper, the authors treat biochemicals as heterogeneous catalytic (HC) this paper in which physical mass transfer completely or significantly controls the overall rate of the process being promoted in the reactor.
Abstract: Biochemical reactors are treated as heterogeneous catalytic reactors in which physical mass transfer completely or significantly controls the overall rate of the process being promoted in the reactor. The treatment used to develop basic design strategies takes into account the special constraints imposed by biological and biochemical phenomena on the systems.
120 citations
TL;DR: In this paper, the power consumption of a single phase and a gas-liquid phase system in a fully baffled stirred tank equipped with dual six-blade Rushton turbines was investigated, and empirical correlations were derived which present new relations in estimation of power consumption and flow regime transitions.
Abstract: Power consumption of a mixing system is a key variable in chemical and bioprocess engineering, the determination of which is of interest of many processes. Besides, prediction of the flooding-loading transition in an aerated stirred tank is crucial for the correct design of aerated stirred tank reactors. In this research, laboratory investigation has been carried out on local and total power consumption of a single phase as well as gas–liquid phase systems in a fully baffled stirred tank equipped with dual six-blade Rushton turbines; moreover, the flow regime behavior of a gas–liquid system was investigated. Results have been compared with data obtained from CFD simulation of experimental setup and the data available in the literature. Reasonable agreement between the experimental and simulation results indicates the validity of the CFD model. Using predicted data some empirical correlations have been derived which present new relations in estimation of power consumption and flow regime transitions in stirred tanks with dual Rushton impellers.
100 citations