Prediction of minimum fluidization velocity for gas-solid fluidization of regular particles in conical vessels

Biswal, K. C.; Bhowmik, Tamali; Roy, Gour Gopal

doi:10.1016/0300-9467(85)80007-1

Cited by 23 publications

(17 citation statements)

References 3 publications

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“…The equations presented by Agarwal and Roy (1988), Fan (1997), andBiswal et al (1985) require the value of porosity which is generally not accurately predicable. Hence, pressure drop cannot be calculated accurately.…”

Section: Fixed Bed Regionmentioning

confidence: 98%

“…Biswal et al (1982Biswal et al ( , 1985 have proposed equations for pressure peak, critical fluidization velocity, and fluctuation ratio for tapered beds of apex angles 10…”

Section: Literature Reviewmentioning

confidence: 99%

“…Murthy et al (1981) have developed equations for prediction of pressure drop for liquid-solid fluidized tapered beds on the lines of Ergun's approach (1952) with different values of constants. Biswal et al (1985) have proposed an equation for calculation of peak pressure drop with modified constants. However, the second constant C 2 is calculated as 0.75, the same as that in Ergun's equation (1952) and is reported to be independent of apex angle of the vessel.…”

Section: Fixed Bed Regionmentioning

confidence: 99%

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Hydrodynamics of gas–solid fluidization in tapered beds

et al. 2009

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Gas-solid fluidization has a wide range of industrial applications like catalytic reactions, combustion, gasification, etc. In a number of these applications, there is particle size reduction during the operation leading to severe entrainment and limitation of operating velocity. The various problems associated with particles of different sizes or changing particles sizes could be overcome by adopting tapered beds in fluidization operation.In the present investigation, the fluidization phenomenon in tapered beds has been critically assessed through experimental investigations using particles of different sizes and materials and wide range of apex angles of the vessels. The effect of particle size and apex angle on the fluidization behaviour is clearly brought out which has not been reported so far in literature. The importance of compressive force existing in tapered beds is highlighted.In addition, correlations for all hydrodynamic characteristics, viz. critical fluidization velocity, minimum velocity for full fluidization, maximum velocity for defluidization, peak pressure drop, fluctuation ratio, compressive force, and hysteresis have been developed some of which are proposed for the first time.La fluidisation gaz-solide revêt un vasteéventail d'applications industrielles comme les réactions catalytiques, la combustion, la gazéification, etc. Pour un certain nombre deces applications, il y a une réduction granulométrique durant l'activité menantà un entraînement età une limitation intenses de la vitesse de fonctionnement. Les divers problèmes liés aux particules de dimensions différentes ou aux dimensions de particules changeantes pourraientêtre surmontésen adoptant les lits coniques dans les activités de fluidisation. Dans le cadre de la présenté etude, lephénomène de fluidisation dans les lits coniques aétéévalué de façon critique au moyen devérifications expérimentales employant des particules de dimensions et de matières différentes et d'un vasteéventail d'angles de sommet de fluidiseurs. L'effet de la dimension des particules et del'angle des sommets sur le comportement de la fluidisation est nettement mis enévidence, ce quin'a pasété soulevéà venir jusqu'ici dans la documentation. L'importance de la force decompression qui existe dans les lits coniques est mise enévidence. De plus, les corrélations relativement a l'ensemble des caractéristiques hydrodynamiques, c.-à-d. la vitesse de fluidisation critique, la vitesse minimale de fluidisation complète, la vitesse maximale de défluidisation, la chute des pics de pression, le taux de fluctuation, la force de compression et l'hystérésis, ontétéélaborées, certaines d'entre ellesétant avancées pour la première fois.

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Section: Fixed Bed Regionmentioning

confidence: 98%

“…Biswal et al (1982Biswal et al ( , 1985 have proposed equations for pressure peak, critical fluidization velocity, and fluctuation ratio for tapered beds of apex angles 10…”

Section: Literature Reviewmentioning

confidence: 99%

Section: Fixed Bed Regionmentioning

confidence: 99%

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Hydrodynamics of gas–solid fluidization in tapered beds

et al. 2009

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“…In the recent past, fluidization in tapered bed is gaining importance in view of its potential application in gas-solid system involving continuously decreasing particle size in combustion and gasification of coal, reduction of iron ores [24], etc. Although some investigations have been carried out in conical bed [25,26]and tapered bed [27,28] for prediction of minimum fluidization velocity under ambient conditions, similar data at elevated temperature conditions in tapered bed are not available. In this present work, investigations have been carried out at elevated temperatures to obtain the correlation of minimum fluidization velocity (independent of bed voidage) in tapered bed for gas-solid system and the correlation has been compared with values obtained by equation of Sau et al [28] proposed for tapered bed in ambient conditions in gas-solid systems.…”

Section: Literature Surveymentioning

confidence: 99%

Hydrodynamic Studies on Conventional and Tapered Fluidized Bed

2016

IJSR

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Abstract:In this project the determination of maximum pressure drop, minimum fluidization velocity, minimum bubbling velocity and fluidization index for various powders are to be studied using a conventional cylindrical bed and a tapered bed. Tapered beds have a velocity gradient along the axis unlike conventional beds. They have been used as an alternative to conventional cylindrical beds to deal with problems such as slugging. Initially air at ambient conditions (310 K) is to be used as the fluidizing medium. High temperature studies will also be carried out using a High temperature fluidized bed (Air temperature up to 1173 K).

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“…The hydrodynamic characteristics in conical bed with flat plate distributor and different cone angle were studied and modeled to show their effect on the fluidization velocity (Kaewklum and Kuprianov, 2008;Biswal et al, 1985). In spite of the widely used conical fluidized bed, its hydrodynamic properties are not fully understood.…”

Section: Introductionmentioning

confidence: 99%

Conical Fluidized Bed with Arc Design for Improved Performance of Gas Distributor

Hamawand

Silva

Jawad

2015

SET

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Particles distributions along a conical fluidized bed were predicted by an alternative arrangement of the minimum fluidization velocity equation. The proposed approach introduces two new equations which present the particle diameter in the bed as function of: height in the bed (Z), angle of inclination of the fluidized bed wall (θ), input flow rate (Q o ), and gas distributor diameter (D o , 2r o ). A novel arc-shaped design of the gas distributor was suggested, which provides enhanced distribution of the gas and enables greater control on the direction of the gas inlet. The model showed that the inclination of the fluidized bed wall should not exceed a critical angle, which can be determined with the set of equations specially developed for this purpose, to prevent inhomogeneous fluidization across the bed and accumulation of particles along the walls.By applying the Box Wilson Method, theoretical data were obtained for constant column diameter at the base (0.05 m), and varying bed height, Z, (range: 0.5 to 1.5 m), velocity of gas inlet, U, (range 0.25 to 1 m s -1 ), and balance factor, a, (range: 0.5 to 1, a new factor), respectively. The angle of inclination of the wall was first predicted based on the above parameters, and subsequently, the particle size distribution along the column was determined. Theoretically the novel arc-shaped distributor design has shown the potential of generating homogeneous fluidization regimes along the bed.

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Prediction of minimum fluidization velocity for gas-solid fluidization of regular particles in conical vessels

Cited by 23 publications

References 3 publications

Hydrodynamics of gas–solid fluidization in tapered beds

Hydrodynamics of gas–solid fluidization in tapered beds

Hydrodynamic Studies on Conventional and Tapered Fluidized Bed

Conical Fluidized Bed with Arc Design for Improved Performance of Gas Distributor

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