Energy demands of different impeller types in gas–liquid dispersions

Fujasová, M.; Linek, V.; Moucha, T.; Prokopová, E.

doi:10.1016/j.seppur.2003.12.015

Cited by 19 publications

(22 citation statements)

References 5 publications

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“…The power dissipated by an impeller in each section of the vessel was measured using the methods described by Fujasová et al . The torque transferred to the impeller shaft was determined using a strain gauge fixed on the shaft.…”

Section: Methodssupporting

confidence: 93%

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Prediction of Power Consumption in a Mechanically Agitated Gassed Reactor in Viscous Batches

et al. 2018

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Volumetric mass transfer coefficient, power input, and gas holdup are key parameters in the design of mechanically agitated gas‐liquid contactors. Although the majority of industrial batches are of higher viscosity, reliable transport characteristics correlations for viscous batches are lacking in literature. These correlations are often based on the power input as the scale of energy dissipation. In order to develop reliable power input correlations, its measurements were carried out in a pilot‐plant vessel using multiple impellers of various types and diameters. Power input correlation shapes providing the best match with the comprehensive database are also expected to predict most precisely the impeller power in industrial‐scale vessels.

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Section: Methodssupporting

confidence: 93%

“…This dimensionless correlation is the most frequently used one . It was originally developed for single‐impeller vessels but it has also been successfully used for one‐scale multiple‐impeller vessels , . As it will be shown later, this equation is, however, the improper one to predict the power input for different impeller diameters.…”

Section: Introductionmentioning

confidence: 99%

Prediction of Power Consumption in a Mechanically Agitated Gassed Reactor in Viscous Batches

et al. 2018

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“…The treatment according to Eq. gives more representative k L a values as demonstrated by Fujasova et al . The correlation closeness was assessed using the relative standard deviation of the differences between experimental and predicted k L a values given by the formula:

true SD = \sqrt{\frac{1}{N - 1} \sum_{j = 1}^{N} {(\frac{k_{normalL} a_{normalexperimental, j} - k_{normalL} a_{normalpredicted, j}}{k_{normalL} a_{normalexperimental, j}})}^{2}}

…”

Section: Methodsmentioning

confidence: 98%

“…For instance, 2RT means a double Rushton turbine and RT+2PBU means a Rushton turbine in the bottom stage with double pitched‐blade impellers up‐pumping in the upper stages. The power dissipated by an impeller in each stage was determined by methods described by Fujasova et al and as presented in . The impellers are depicted in Fig.…”

Section: Methodsmentioning

confidence: 99%

Volumetric Mass Transfer Coefficient in Fermenters: Scale‐up Study in Viscous Liquids

et al. 2017

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In the design of mechanically agitated fermenters, the volumetric mass transfer coefficient k L a often becomes the key parameter. In case of viscous liquids, k L a prediction based on literature correlations suffers from a wide distribution. The aim is to provide reliable k L a correlations based on a large experimental data set obtained using the dynamic pressure method, the physical correctness of which was verified earlier. Multiple-impeller fermenters of two scales were used. The impeller tip speed, rather than the power input, revealed to be the proper term for prediction of k L a. When the impeller power number is used, k L a values for various impeller types can be predicted by a common correlation which, based on a wide range of operational conditions, can be applied in the design.

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“…One of the required transport characteristics for designing gas-liquid mixed systems is the intensity of liquid-phase mixing [15]. The bulk circulation is the rate-determining step for liquid mixing in stirred vessels.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of the Mixing Time in a Jet‐Mixed Gas‐Liquid System

Amiri

Moghaddas

2010

Chem Eng & Technol

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In the present work, the impeller in the conventional gas-liquid mixed vessels was replaced by a fluid jet as the mixer. Using an experimental setup, the effect of several parameters on the mixing time as a measure of the liquid-phase mixing intensity, which is one of the required transport characteristics for designing gasliquid mixed systems, was studied. The results show that gas injection decreases the mixing time in comparison with the ungassed condition, but the mixing time is not necessarily decreased by increasing the gassing rate. On the basis of the amount of the jet Reynolds number and gassing rate, and thus the created circulation pattern, the mixing time may be decreased or increased. Also, the location of the probe for cases in which there are more dead zones in the vessel have a considerable effect on the measured mixing time. With increasing uniformity of the velocity domain, the influence of the probe location was reduced. Also, by increasing the jet flow rate and decreasing the nozzle diameter, the length of the jet, the amount of entrained bulk fluid, and the intensity of recirculation flow increased, and thus the mixing time decreased.

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Energy demands of different impeller types in gas–liquid dispersions

Cited by 19 publications

References 5 publications

Prediction of Power Consumption in a Mechanically Agitated Gassed Reactor in Viscous Batches

Prediction of Power Consumption in a Mechanically Agitated Gassed Reactor in Viscous Batches

Volumetric Mass Transfer Coefficient in Fermenters: Scale‐up Study in Viscous Liquids

Experimental Study of the Mixing Time in a Jet‐Mixed Gas‐Liquid System

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