An experimental investigation into vapor dispersion and solid suspension in boiling stirred tank reactors

Dohi, Naoki; Matsuda, Yukimasa; Shimizu, Kazuhiro; Minekawa, K.; Kawase, Y.

doi:10.1016/s0255-2701(01)00142-8

Cited by 18 publications

(23 citation statements)

References 7 publications

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“…which has also been verified in recent studies [13,27]. It is noted the constant S value strongly depends on the vessel geometry [27] and impeller type.…”

Section: Resultssupporting

confidence: 80%

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A Digital Imaging Technique for the Analysis of Local Inhomogeneities from Agitated Vessels

Visuri¹,

Laakkonen²,

Aittamaa³

2007

Chem Eng & Technol

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A novel, cheap and simple technique for the analysis of the mixing properties from a stirred vessel is introduced. The technique is based on a digital imaging technique and the analysis can be undertaken based on the properties of the image. Using this technique, it is easy to analyze mixing inhomogeneities. Test measurements with non-Newtonian viscous, aqueous xanthan solutions and fluids as well as liquid-particle suspensions showed that the developed method is a quick and quantitative tool for the analysis of local mixing inhomogeneities, mixing times and particle suspension speeds.

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“…which has also been verified in recent studies [13,27]. It is noted the constant S value strongly depends on the vessel geometry [27] and impeller type.…”

Section: Resultssupporting

confidence: 80%

“…Sampling [13] and conductivity experiments [14] could be used, but they disturb the flow field in a similar manner to that described above.…”

Section: Introductionmentioning

confidence: 99%

A Digital Imaging Technique for the Analysis of Local Inhomogeneities from Agitated Vessels

Visuri¹,

Laakkonen²,

Aittamaa³

2007

Chem Eng & Technol

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“…The phenomena in boiling stirred tanks are quite different from those in cold gas-dispersing stirred tanks (Smith, 2006). Smith et al (Smith and Katsanevakis, 1993;Smith and Millington, 1996;Smith et al, 2004) and our own group (Dohi et al, 1999;Dohi et al, 2002;Takahashi et al, 2006) have studied mixing in stirred tanks with boiling liquids. The power consumption, vapour hold-up, mixing time and solid suspension in boiling stirred tanks have been examined.…”

Section: Introductionmentioning

confidence: 96%

Vapour generation from the impellers in boiling stirred tank reactors

Fukuda

Tokumura

Znad

et al. 2009

Chemical Engineering Research and Design

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“…But at the same time one advantage of the multiple impeller system is that more homogeneous suspension can be obtained as compared to the single impeller confi guration. Dohi et al (2002) important roles in the re-distribution of the solids suspended by the lowest impeller throughout the reactor. This may be due to the fact that the upper impellers are relatively unaffected by the gas sparging (as they get the already dispersed gas from the Figure 17.…”

Section: Multiple Impeller Systemmentioning

confidence: 99%

“…In particular, there is very little information available in the literature regarding the hydrodynamic behaviour of vapour and solid phases in (boil-off threephase reactors). Recently Dohi et al (2002) …”

Section: Solid Suspension In Boiling Liquidmentioning

confidence: 99%

Review on Mixing Characteristics in Solid‐Liquid and Solid‐Liquid‐Gas Reactor Vessels

Kasat

Pandit

2005

Can J Chem Eng

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REVIEW In carrying out the physical mass transfer processes and chemical reactions in the gas-liquid-solid systems, in which liquid is the continuous phase and where the solid and gas phase are the discontinuous phases, there is often a need to suspend the solid particles in the presence of gas. Stirred tanks are often employed for this purpose as slurry reactors, especially for discontinuous/batch operations and for smaller production levels. The main task of the stirrer in an aerated suspension system is to suspend the solids particles completely so as to expose their total surface area for the reaction and/or for mass transfer, to disperse the gas uniformly throughout the vessel and to provide liquid mixing patterns for an intimate contact between the phases. Thus, mechanically agitated reactors are extensively used in the industry to handle the three-phase systems and fi nd application in a wide range of processes such as catalyzed oxidation and hydrogenation reactions, polymerization, evaporative crystallization, aerobic fermentation, froth fl oatation, microbial coal desulphurization, gold leaching, and bacterial sulphide oxidations. In all these applications, simultaneous dispersion of gas and the suspension of the solids by the impellers are of vital importance. Review on Mixing Characteristics in SolidReview on Mixing Characteristics in SolidLiquid and Solid-Liquid-Gas Reactor VesselsGopal R. Kasat and Aniruddha B. Pandit* Chemical Engineering Division, University Institute of Chemical Technology (UICT), University of Mumbai, Matunga, Mumbai 400-019, IndiaFor a reliable design of a three-phase stirred tank reactor, it is important to know the complex hydrodynamic problems (i.e. phase-phase interactions) associated with the demands of simultaneous gas dispersion and solids suspension with a single or multiple impellers. One of the most important parameters for the assessment of the performance of the impellers for solid suspension (both in the absence and in the presence of gas), is the minimum impeller speed required for the complete offbottom suspension of the solids in the vessel. (Zwietering, 1958;Wiedmann et al., 1980;Chapman et al., 1981 Chapman et al., , 1983Frijlink et al., 1990;Rewatkar et al., 1991a; Mechanically agitated reactors with single and multiple impeller systems are used in the industry for the various three-phase mixing processes such as crystallization, fermentation, and hydrogenation, etc. The paper reviews the experimental work reported in the literature along with different techniques used for the measurement of the specifi c quantities such as minimum or critical impeller speed for solid suspension. The work critically surveys the literature and makes specifi c recommendations for the use of appropriate correlations and conditions to be used for the success of such equipment. This assessment will put all the relevant literature on a common footing and will help to validate work reported earlier.Les réacteurs agités mécaniquement munis d'une seule turbine et de turbines mult...

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An experimental investigation into vapor dispersion and solid suspension in boiling stirred tank reactors

Cited by 18 publications

References 7 publications

A Digital Imaging Technique for the Analysis of Local Inhomogeneities from Agitated Vessels

A Digital Imaging Technique for the Analysis of Local Inhomogeneities from Agitated Vessels

Vapour generation from the impellers in boiling stirred tank reactors

Review on Mixing Characteristics in Solid‐Liquid and Solid‐Liquid‐Gas Reactor Vessels

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