Fluid flow pattern, minimum spouting velocity and pressure drop in spouted beds

Grbavčić, Željko; Vuković, D. V.; Zdanski, F. K.; Littman, H.

doi:10.1002/cjce.5450540105

Cited by 76 publications

(30 citation statements)

References 10 publications

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“…Figure 1 and Table 3 show that previous equations for predicting minimum spouting velocities may be in error by con- siderable margins for large columns. The Grbavcic et al (1976) equation for spherical particles appears to work well, but more data are needed for rounded particles to test it. The Grbavcic et al (1976) equation for spherical particles appears to work well, but more data are needed for rounded particles to test it.…”

mentioning

confidence: 99%

Spouted bed hydrodynamics in a 0.91 m diameter vessel

Lim

Grace

1987

Can J Chem Eng

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Hydrodynamic measurements were obtained in a flat-based half-cylindrical column of diameter 0.91 m and inlet orifice diameters of 76 to 114 mm. Beds of 3.5 to 6.7 mm diameter particles with static depths of 0.53 to 1.83 m were spouted with air. In agreement with measurements by earlier workers in smaller columns, it was found necessary to operate with inlet orifice diameters less than about 30 times the mean particle diameter in order to be able to achieve stable spouting. Correlations for minimum spouting velocity developed on small vessels generally gave poor predictions for the large diameter vessel employed in this work and failed to predict the observed dependence of Urn, on the static bed height. Substantial dead regions where particles were stagnant were observed in the lower outer portion of the vessel. Other aspects of behaviour studied, including spout diameters and shapes, fountain heights, pressure profiles and gas velocities in the annulus, were qualitatively similar to those in smaller columns, although equations developed for the smaller vessels did not always provide accurate predictions. Des mesures hydrodynamiques ont ttk obtenues dans une colonne semi-cylindrique a fond plat d'un diamktre de 0.91 m et dont le diamktre d'entrke de I'orifice varie entre 76 et 114 mm. De I'air est injecte dans des lits de particules de 3.5 a 6,7 mm de diamktre et d'une profondeur statique se situant entre 0,53 et 1.83 m. En accord avec des mesures effectukes par d'autres chercheurs sur des colonnes de dimensions inferieures, il apparait nkcessaire d'opkrer avec des diamktres d'orifice infkrieurs B 30 fois le diamktre moyen des particules si I'on veut pouvoir effectuer un lit a jet stable.Les corrklations de la vitesse minimale Ctablies sur des colonnes de petites dimensions donnent genCralement de mauvaises prkdictions sur la colonne de large diamttre utilisee dans ce travail. En outre, ces corrClations ne pridisent pas la variation observCe de Urn, avec la hauteur statique du lit. On a observe par ailleurs d'importantes rkgions ob les particules sont stagnantes dans la partie extkrieure basse de la colonne. Les autres aspects du comportement CtudiC, parmi lesquels le diamktre et la forme des jaillissements, la hauteur de la fontaine, le protil de pression et la vitesse des gaz dans la partie annulaire, sont qualitativement similaires a ceux des colonnes plus petites, bien que les equations dkveloppies pour les colonnes plus petites ne fournissent pas toujours de prkdictions prkcises.

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mentioning

confidence: 99%

Spouted bed hydrodynamics in a 0.91 m diameter vessel

Lim

Grace

1987

Can J Chem Eng

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“…Figure 2 shows that there is a signficiant difference between the pressure measured in the inlet tube, AP,,, and APs, obtained by extrapolating the experimental data to z = 0. Although such differences have been reported by others (GrbavEiC et al, 1976;Epstein et al, 1978) they cannot be calculated quantitatively because the fluid mechanical condition just downstream from the inlet to the spout is difficult to describe accurately. In the absence of an experimental value for APsi, the calculated value of APlns is a reasonable approximation of it in a flat bottom column.…”

Section: Spout-annulus Interfacial Pressure Conditionmentioning

confidence: 77%

“…The measured value of APsi/APM is 0.830. Equation (8) does a much better job of predicting the profile than do the other equations (Lefroy and Davidson, 1969;GrbavEiC et al, 1976). Note in Figure 5 that the experimental profile is approaching the diagonal line which represents the profile in a fluidized bed.…”

Section: Spout-annulus Interfacial Pressure Conditionmentioning

confidence: 90%

An axisymmetric model of flow in the annulus of a spouted bed of coarse particles. Model, experimental verification and residence time distribution

Littman¹,

Morgan²,

Narayanan³

et al. 1985

Can J Chem Eng

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An axisymmetric model of flow in the annulus of a spouted bed of coarse particles which takes into account non‐Darcy flow and utilizes a new and general axial pressure boundary condition at the spout‐annulus interface is presented. The pressure boundary condition and the annulus pressure distribution are experimentally verified and the model used to calculate the residence time distribution and the flowrate at the top of the annulus. In addition, the average axial velocity profile in the annulus is calculated and compared with predictions of several one‐dimensional flow models.

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“…More rigorous expressions for coned bottom spouted beds have been derived by Rovero et al (1983), but Equation (1) is used here for simplicity. Applying Equation (1) at the top of the annulus, the minimum superficial spouting velocity is obtained (Grbavcic et al, 1976) Outlet conditiors f Uo ,Gout where z, = ( D , -d0)/2 tan (8/2). The volume fraction of the spout phase (6) is assumed constant throughout.…”

Section: Annulus Gas Velocitymentioning

confidence: 99%

Semicompartmental model for spouted bed reactors

Viswanathan

1984

Can J Chem Eng

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Fluid flow pattern, minimum spouting velocity and pressure drop in spouted beds

Cited by 76 publications

References 10 publications

Spouted bed hydrodynamics in a 0.91 m diameter vessel

Spouted bed hydrodynamics in a 0.91 m diameter vessel

An axisymmetric model of flow in the annulus of a spouted bed of coarse particles. Model, experimental verification and residence time distribution

Semicompartmental model for spouted bed reactors

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