Pressure drop for cocurrent downflow of gas‐solids suspensions

Kim, J. M.; Seader, J. D.

doi:10.1002/aic.690290302

Cited by 24 publications

(14 citation statements)

References 30 publications

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“…Limited early studies were reported by Shimizu et al (1978) and Kim and Seader (1983). Limited early studies were reported by Shimizu et al (1978) and Kim and Seader (1983).…”

Section: Brief Historymentioning

confidence: 99%

Cocurrent downflow circulating fluidized bed (downer) reactors — A state of the art review

Zhu

et al. 1995

Can J Chem Eng

175

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In the last decade, cocurrent downflow circulating fluidized bed reactors, called "downer" reactors, have been proposed as an alternative to upflow circulating fluidized bed, or "riser", reactors. In this paper, published results on downer studies are siimmarized and future directions of research are recommended. Downer reactors are shown to have several distinct advantages over upflow circulating fluidized bed reactors and can potentially be used in many industrial processes, mainly due to a more uniform gas and solids flow structure compared with risers.Depuis une dizaine d'annks, les rtacteurs B lit fluidist circulant B cwourant descendant ont ktk propos6s pour faire concurrence aux rhcteurs B lit fluidisk circulant ascendant. Dans cet article, on rtsume les rksultats publits des ttudes sur les rtacteurs de type descendant, et des directions sont recomrnand&s pour la recherche. On a trouvt que les rhcteurs descendants offraierit des avantages particuliers par rapport aux rhcteurs B lit fluidid circulant ascendant et qu'ils Ctaient potentiellement inttressants dans de nombreux praddts industriels, en raison principalement d'une structure d'kcoulement du liquide et des solides plus uniforme que dans le cas des rtacteurs ascendants.Keywords. downer reactor, co-current downflow, fluidized bed, short contact reactor. n the last two decades, considerable progress has been Nomenclature = particle diameter, m = axial gas dispersion coefficient, m2/s = axial solids dispersion coefficient, m2/s = radial gas dispersion coefficient, m2/s = radial solids dispersion coefficient, m2/s = functions of radial ratio, defined by Equations (10) = Froude number, [ =(Us-t~,)/(gd,,)~.~l = gravitational acceleration constant, m/s2 and (13), respectively

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“…Limited early studies were reported by Shimizu et al (1978) and Kim and Seader (1983). Limited early studies were reported by Shimizu et al (1978) and Kim and Seader (1983).…”

Section: Brief Historymentioning

confidence: 99%

Cocurrent downflow circulating fluidized bed (downer) reactors — A state of the art review

Zhu

et al. 1995

Can J Chem Eng

175

View full text Add to dashboard Cite

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“…The axial behaviors in downer reactors have been investigated for long [8][9][10][11][12][13][14]. During these experiments, the superficial gas velocity (SGV) remains unchanged along the reactor length.…”

Section: Introductionmentioning

confidence: 99%

Axial flow structure at the varying superficial gas velocity in a downer reactor

Deng

Liu

Wei

et al. 2004

Chemical Engineering Journal

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“…However, our understanding of gas-solids two-phase flow in the CDCFB, especially in units near to pilot scale, is still limited. Kim and Seader investigated a CDCFB with a 13 mm ID tube and spherical glass beads of 329 ym [2]. Wang et al studied the hydrodynamics of a CDCFB with a 140 mm ID tube and…”

Section: Introductionmentioning

confidence: 99%

Gas mixing in the cocurrent downflow circulating fluidised bed

Wei

et al. 1995

Chem Eng & Technol

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An experimental study on the gas dispersion behaviour of a cocurrent downflow gas-solids suspension in a 140 mm i.d. circulating fluidised bed (CDCFB) using the steady-state tracer method is presented. The influence of gas velocity, solids circulating rate and particle density on radial gas dispersion has been examined. Gas dispersion can well be described by an eddy diffusion mechanism and a proposed two dimensional dispersed plug-flow model can fit the experimental data very well. Correlations of the radial diffusion coefficient were obtained. It is found that the axial diffusion coefficient obtained in the CDCFB is much lower than that in conventional circulating fluidised beds.

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Pressure drop for cocurrent downflow of gas‐solids suspensions

Cited by 24 publications

References 30 publications

Cocurrent downflow circulating fluidized bed (downer) reactors — A state of the art review

Cocurrent downflow circulating fluidized bed (downer) reactors — A state of the art review

Axial flow structure at the varying superficial gas velocity in a downer reactor

Gas mixing in the cocurrent downflow circulating fluidised bed

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