Power and mass transfer correlations for the design of multi-impeller gas–liquid contactors for non-coalescent electrolyte solutions

Volumetric mass transfer coefficients, kLa, just as power input are considered as essential parameters for mechanically agitated gas‐liquid contactors in relation to their optimization and design. The knowledge of power input is crucial for the prediction of other mass transfer characteristics. A power input correlation is created for the industrial design of the process with a non‐coalescent batch that would be appropriate for a broad range of operational conditions. The recommended resulting correlation is able to predict the power input for impellers in industrial‐scale design for a significant scope of operational conditions.

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“…The simplest correlation, which is commonly employed to correlate the data measured in multiple‐impeller vessels , has the following form:

true \frac{P_{normalg}}{V_{normalL}} = K_{1} f^{{normalK}_{2}} {vs}^{{normalK}_{3}}

…”

Section: Introductionmentioning

confidence: 99%

Power Input Prediction in Agitated Gas‐Liquid Contactors with Non‐coalescent Batch

2019

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“…where vs means the superficial gas velocity. However, this equation is not transferable to other systems; it was applied to power input prediction of the volumetric mass transfer coefficient, e.g., by Linek et al and Moucha et al , . A simple correlation, based on an ungassed impeller power, P u , instead of impeller frequency, acquires the form:

true \frac{P_{normalg}}{V_{normalL}} = K_{1} {(\frac{P_{normalu}}{V_{normalL}})}^{K_{2}} v s^{K_{3}}

…”

Section: Introductionmentioning

confidence: 99%

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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“…. The diameter ( T ) of the tank was 0.30 m and the height of the tank ( H T ) was 0.75 m. The ungassed liquid level was maintained at a height H = 1.8 T with a deionized water volume of 0.036 m. As a standard configuration, four 0.03 m‐wide baffles were symmetrically mounted in the tank.…”

Section: Methodsmentioning

confidence: 99%

“…Therefore, the volumetric mass transfer coefficient, k L a , is often considered a key parameter in the performance, design, and scale‐up of stirred tank reactors. During the past few decades, studies of k L a in gas–liquid systems have been reported extensively, and a number of correlations have been obtained for reactor design and scale‐up . However, all those reports mainly focused on k L a at ambient temperature when the vapor pressure can be neglected compared with the operating pressure, while many of the processes mentioned above are exothermic and ‘hot’, operating at higher temperatures when the assumption of negligible vapor pressure is likely to be invalid.…”

Section: Introductionmentioning

confidence: 99%

Gas-liquid mass transfer for coalescent system in a hot-sparged triple-impeller stirred reactor

Zhang

Gao

Xin

et al. 2016

J. Chem. Technol. Biotechnol.

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BACKGROUND: Industrial processes are often operated in hot-sparged agitated reactors and the volumetric mass transfer coefficient (k L a) is one of the most important parameters for design and scale-up of stirred tank reactors. In this work, the power consumption and volumetric mass transfer coefficient were studied under hot-sparged conditions. RESULTS: The relative power demand (RPD) increases remarkably with temperature according to a power law with an exponent of 0.44. k L a increases significantly with power consumption and superficial gas velocity according to power laws with exponents 0.56 and 0.28, respectively. However, the temperature has little influence on k L a, with a power law exponent of only 0.13 for a coalescent system, much smaller than the exponent of 1.64 for a non-coalescent system stirred by a similar triple-impeller. CONCLUSIONS: In a hot-sparged coalescent system, an increase in temperature cannot enhance the mass transfer rate as it does in a non-coalescent system. As a practical guide to industrial applications, it is more effective to enhance the gas-liquid mass transfer by increasing the power consumption than by increasing the gas flow rate, especially when the gas flow rate is already very high. The empirical relationships between power consumption and k L a obtained in this work can provide helpful guidance for industrial design and operation of hot-sparged stirred reactors.

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Power and mass transfer correlations for the design of multi-impeller gas–liquid contactors for non-coalescent electrolyte solutions

Cited by 21 publications

References 34 publications

Power Input Prediction in Agitated Gas‐Liquid Contactors with Non‐coalescent Batch

Power Input Prediction in Agitated Gas‐Liquid Contactors with Non‐coalescent Batch

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

Gas-liquid mass transfer for coalescent system in a hot-sparged triple-impeller stirred reactor

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