The gas content in a three-phase fluidized bed

Vail, Yu. K.; Manakov, N. Kh.; Manshilin, V. V.

doi:10.1007/bf00719139

Cited by 4 publications

(3 citation statements)

References 3 publications

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“…In the liquid phase, a considerable backmixing has been reported (Vail et al, 1968;Ostergaard, 1969;Michelsen and Ostergaard, 1970;Muroyama et al, 1978 and El-Temtamy et a]., 1979). The axial thermal conductivity k,, in the gas-liquid-solid fluidized bed is mainly concerned with the backmixing of each phase involved, since the thermal conduction through each phase is unimportant.…”

Section: Discussionmentioning

confidence: 99%

Wall‐to‐bed heat transfer in liquid—solid and gas—liquid—solid fluidized beds part II: Gas—liquid—solid fluidized beds

1986

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Wall-to-bed heat transfer in gas-liquid-solid fluidized beds with a cocurrent upflow was analyzed on the basis of a series thermal resistance model. The effective radial thermal conductivity and the apparent wall heat transfer coefficient were determined over a wide range of experimental conditions. The behavior of the effective thermal conductivity strongly depends on the flow mode for the three-phase fluidized bed, directly indicating the trend of the radial liquid mixing. The modified Peclet number for the radial thermal diffusivity takes on a minimum with respect to the liquid velocity in a manner similar to that in a liquid-solid fluidized bed, but the value of the modified Peclet number decreases significantly with gas velocity. The apparent wall heat transfer coefficient can be correlated well with a Colburn type equation which at zero gas velocity reduces to the same equation as that proposed for liquid-solid fluidization, as follows:Le transfert de chaleur lit-paroi dans les lits fluidises gaz-liquide-solides avec un Ccoulement ascendant cocourant a CtC analysk a I'aide d'un modkle de resistances thermiques en sCrie. La conductivitk thermique radiale effective et le coefficient de transfert de chaleur apparent a la paroi ont CtC dCterminCs pour des conditions exp5rimentales trks variCes.Le comportement de la conductivitk thermique effective dtpend fortement du mode d'tcoulement dans le lit fluidist trois phases, ce qui indique directement la tendance du mklangeage radial du liquide. Le nombre de Peclet modifiC pour la diffusivitt thermique radiale atteint un minimum avec une augmentation de la vitesse du liquide de la m&me manikre que dans un lit fluidisk solides-liquide, mais la valeur du nombre de Peclet modifiC diminue de manikre significative avec la vitesse des gaz. Le coefficient de transfert de chaleur apparent ti la paroi peut &tre corrClC a I'aide d'une Cquation de type Colburn qui, lorsque la vitesse des gaz est nulle, devient identique a celle proposCe pour la fluidisation solides-liquide, a savoir: j b = 0,137 Re;,,-"."' hree-phase fluidized beds with cocurrent upflow of gas

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Section: Discussionmentioning

confidence: 99%

Wall‐to‐bed heat transfer in liquid—solid and gas—liquid—solid fluidized beds part II: Gas—liquid—solid fluidized beds

1986

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“…The gas phase holdup increases with an increase in Morton's number. It is evident from the analysis that the gas phase holdup is a function of all fundamental as well as operating variables for threephase¯uidizing systems 7,19,21,22,30,31 , ie:…”

Section: Gas Holdupmentioning

confidence: 99%

Minimum fluidization velocity and gas holdup in gas–liquid–solid fluidized bed reactors

Ramesh

Murugesan

2002

J of Chemical Tech & Biotech

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Experiments were performed to study the hydrodynamics of a cocurrent three-phasē uidized bed with liquid as continuous phase. Based on the 209 experimental data (with four liquid systems and ®ve different particles) along with 115 literature data from six different sources on minimum¯uidization velocity, a unique correlation for the estimation of minimum¯uidization velocity in two-phase (u g = 0) as well as in three-phase systems is developed. A data bank consisting of 1420 experimental measurements for the fractional gas phase holdup data with a wide range of variables is used for developing empirical correlations. Separate correlations are developed for twō ow regimes observed in this present work. The proposed correlations are more accurate and simpler to use.

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“…At increased gas velocity bubble coalescence became important and a sharp increase in mixing was observed. Vail et al 24) studied turbulent mixing of the liquid phase in two-and three-phase fluidized beds of 1 14.3cm diameter. Air was used as the gas phase, tap water as the liquid phase, and spheres having a diameter of 0.87mmas the solid phase.…”

Section: Introductionmentioning

confidence: 99%

Axial dispersion characteristics of three phase fluidized beds.

Kim

1983

J. Chem. Eng. Japan

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The gas content in a three-phase fluidized bed

Cited by 4 publications

References 3 publications

Wall‐to‐bed heat transfer in liquid—solid and gas—liquid—solid fluidized beds part II: Gas—liquid—solid fluidized beds

Wall‐to‐bed heat transfer in liquid—solid and gas—liquid—solid fluidized beds part II: Gas—liquid—solid fluidized beds

Minimum fluidization velocity and gas holdup in gas–liquid–solid fluidized bed reactors

Axial dispersion characteristics of three phase fluidized beds.

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