Volumetric mass transfer coefficient in multiple-impeller gas–liquid contactors. Scaling-up study for various impeller types

Labík, Libor; Vostal, Radek; Moucha, T.; Rejl, F.J.; Kordač, M.

doi:10.1016/j.cej.2013.11.066

Cited by 21 publications

(12 citation statements)

References 28 publications

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“…While most such studies have concentrated on stirred tanks [1][2][3][4][5] or bubble columns [6][7][8][9][10], relatively few investigations have considered mass transfer in wall-driven gas-liquid flows. In this work, a mass transfer correlation is developed for semi-batch gas-liquid Taylor vortex flow wherein fluid motion is driven by the rotation of a cylinder and by axial passage of buoyant gas bubbles.…”

Section: Introductionmentioning

confidence: 99%

Experimental measurement of oxygen mass transfer and bubble size distribution in an air–water multiphase Taylor–Couette vortex bioreactor

Ramezani

Kong

Gao

et al. 2015

Chemical Engineering Journal

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h i g h l i g h t sMean bubble size, and size distribution in vertical gas-liquid Taylor vortex flow. Mass transfer coefficients for vertical gas-liquid Taylor vortex flow. Wall-driven shear produces prolate rather than oblate bubble shapes. Bubble size and spatial distribution explains low mass transfer coefficients. High wall area in annular geometry has significant impact on mass transfer. a b s t r a c tExperimental measurements of the volumetric liquid mass transfer and bubble size distribution in a vertically oriented semi-batch gas-liquid Taylor-Couette vortex reactor with radius ratio g = r i /r o = 0.75 and aspect ratio C = h/(r o À r i ) = 40 were performed, and the results are presented for axial and azimuthal Reynolds number ranges of Re a = 11.9-143 and Re H = 0-3.5 Â 10 4 , respectively. Based on these data, power-law correlations are presented for the dimensionless Sauter mean diameter, bubble size distribution, bubble ellipticity, and volumetric mass transfer coefficient in terms of relevant parameters including the axial and azimuthal Reynolds numbers. The interaction between wall-driven Taylor vortices and the axial passage of buoyancy-driven gas bubbles leads to significantly different dependencies of the mass transfer coefficient on important operating parameters such as inner cylinder angular velocity and axial superficial gas velocity than has been observed in horizontally oriented gas-liquid Taylor vortex reactors. In general, the volumetric mass transfer coefficients in vertical Taylor vortex reactors have a weaker dependence upon both the axial and azimuthal Reynolds numbers and are smaller in magnitude than those observed in horizontal Taylor vortex reactors or in stirred tank reactors. These findings can be explained by differences in the size and spatial distribution of gas bubbles in the vertically oriented reactor in comparison with the other systems.

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Section: Introductionmentioning

confidence: 99%

Experimental measurement of oxygen mass transfer and bubble size distribution in an air–water multiphase Taylor–Couette vortex bioreactor

Ramezani

Kong

Gao

et al. 2015

Chemical Engineering Journal

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“…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: 95%

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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“…Reactor amplification refers to the design and manufacture of reactors based on experimental data obtained from laboratory reaction equipment; the designed reactors are compatible with large-scale reactions during industrial production [6][7][8][9][10][11]. The design of reactor amplification needs to follow certain criteria such as theoretical amplification for the momentum, mass and energy balance equations of the reaction system [12,13]. Van Geem et al [14] performed dimensional analysis on the model equations to design the ideal pilot plant reactor by applying similarity theory to the amplification equations of the reaction system [12,13].…”

Section: Introductionmentioning

confidence: 99%

“…The design of reactor amplification needs to follow certain criteria such as theoretical amplification for the momentum, mass and energy balance equations of the reaction system [12,13]. Van Geem et al [14] performed dimensional analysis on the model equations to design the ideal pilot plant reactor by applying similarity theory to the amplification equations of the reaction system [12,13]. Van Geem et al [14] performed dimensional analysis on the model equations to design the ideal pilot plant reactor by applying similarity theory to the amplification and reduction of steam cracking furnaces.…”

Section: Introductionmentioning

confidence: 99%

Simulation of the Scale-up Process of a Venturi Jet Pyrolysis Reactor

Lv¹,

Zhang²,

Hao³

2019

Metals

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Micro- and nano-sized cerium oxide particles can be prepared through pyrolyzing cerium chloride solution directly in the venturi jet pyrolysis reactor. Micro- and nano-sized cerium oxide particles have better performance and higher application value. To increase the production of micro-and nano-sized cerium oxide, it is necessary to scale up the venturi jet pyrolysis reactor. According to the geometric similarity principle, the scale-up of the venturi jet pyrolysis reactors utilize dimensional analysis methods, with FLUENT13.0 and user-defined functions, following the mathematical simulation of the resulting enlarged reactors. After the dimensional analysis, the empirical formula obtained between the reactants and all the parameters is Q = 2.240727 × 10−4P0.004568ρ0.26223d−0.24801V1.25714n0.076479μ−0.26628, and the geometrical scale-up of the reactors needs to follow V = 0.0209d0.196. The results in this study can provide data support for the future optimization and amplification of reactors.

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Volumetric mass transfer coefficient in multiple-impeller gas–liquid contactors. Scaling-up study for various impeller types

Cited by 21 publications

References 28 publications

Experimental measurement of oxygen mass transfer and bubble size distribution in an air–water multiphase Taylor–Couette vortex bioreactor

Experimental measurement of oxygen mass transfer and bubble size distribution in an air–water multiphase Taylor–Couette vortex bioreactor

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

Simulation of the Scale-up Process of a Venturi Jet Pyrolysis Reactor

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