Models for Predicting Average Bubble Diameter and Volumetric Bubble Flux in Deep Fluidized Beds

Agu, Cornelius Emeka; Pfeifer, Christoph; Eikeland, Marianne Sørflaten; Tokheim, Lars-André; Moldestad, Britt Margrethe Emilie

doi:10.1021/acs.iecr.7b04370

Cited by 23 publications

(28 citation statements)

References 32 publications

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“…The Baeyens and Geldart (1974) model under predicts the experimental data for all aspect ratios. The experimental data agree well with the Agu et al (2018) model for h 0 / < 1.5. Particles with sphericity of 0.85 are assumed in the Agu et al model.…”

Section: Minimum Slugging Velocitysupporting

confidence: 79%

Study of fluidized bed regimes using Computational Particle Fluid Dynamics

Jaiswal

Agu

Thapa

et al. 2018

Linköping Electronic Conference Proceedings

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The fluidization technology has a wide range of applications. In chemical synthesis, fluidized bed is used to enhance heat and mass transfer between the reacting species. More application of this technology can also be seen in pneumatic transport and circulation of solid particles. The different applications require different flow regimes. This study investigates the influence of initial bed height on the fluidized bed regime transition using the Computational Particle Fluid Dynamics (CPFD) software, Barracuda VR. The simulations are performed for a specific powder with a narrow particle size distribution. The results from the simulations are compared with the experimental data and correlations in the literature. The minimum fluidization velocity drop to a stable value and the bubbling velocity remains constant with an increase in the bed height. The gas velocity at onset of slugging decreases while that of turbulent increases to a stable value as the bed height increases.

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Section: Minimum Slugging Velocitysupporting

confidence: 79%

Study of fluidized bed regimes using Computational Particle Fluid Dynamics

Jaiswal

Agu

Thapa

et al. 2018

Linköping Electronic Conference Proceedings

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“…The bubble rise velocity for all cases declines with the bed height. The bubble rise velocity reported by Agu et al 28 is expressed as:

true u_{normalb} = φ_{normalN} (U - U_{mf}) + 12.51 φ_{normalD} {(U - U_{normalmf})}^{0.362} d_{normalb}^{0.52}

…”

Section: Resultsmentioning

confidence: 99%

Investigation of Bubble Behavior in Gas‐Solid Fluidized Beds with Different Gas Distributors

Jang

Feng

2021

Chem Eng & Technol

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The behavior of gas bubbles in a gas‐solid fluidized bed was investigated by computational fluid dynamics simulation. A two‐phase flow model incorporating the kinetic theory of granular flow was used to study the effect of gas distributor design on the size distribution and the rise velocity of gas bubbles in the bed column. The experiments were conducted on four gas distributors with different orifice sizes and pitches. The geometry of the gas distributor had a significant influence on the bubble behavior in the gas‐solid fluidized bed. The effects of static bed height and superficial gas velocity were also considered. Bubble diameter and bubble rise velocity increased with gas velocity. However, at low bed height, the deviation in bubble size was indistinct because at higher gas velocity the rising tendency of the bubble formed just above the gas distributor increased and the probability of bubble coalescence decreased.

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“…By using the particledependent average bubble diameter shown in Eq. (2) as proposed by Agu et al (2018), Eq. (1) predicts the behavior in beds with different particle properties.…”

Section: Modelling and Scaling Upmentioning

confidence: 99%

A new Approach for Scaling Up from a Small Cold to a Large Hot Bed for Biomass Conversion in a Bubbling Fluidized Bed Reactor

Agu¹,

Thapa²,

Pfeifer³

et al. 2021

Linköping Electronic Conference Proceedings

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Bubbling fluidized beds are simple and attractive means of achieving efficient conversion of biomass if particle segregation and the associated effects are minimized. To improve the knowledge of fluidized bed reactor design, this paper compares the behavior of a hot bed containing a certain amount of biomass with the behavior in a cold bed having the same biomass loads and particle properties. An approach for scaling up a cold bed to a large hot bed for the same volume fraction of biomass is introduced. The proposed scheme uses the bed expansion ratio as an output from the cold bed. This approach provides an accurate means of attaining dynamic similarity in bubbling behavior between two different beds without constraining the fluid and particle properties as well as the bed height.

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Models for Predicting Average Bubble Diameter and Volumetric Bubble Flux in Deep Fluidized Beds

Cited by 23 publications

References 32 publications

Study of fluidized bed regimes using Computational Particle Fluid Dynamics

Study of fluidized bed regimes using Computational Particle Fluid Dynamics

Investigation of Bubble Behavior in Gas‐Solid Fluidized Beds with Different Gas Distributors

A new Approach for Scaling Up from a Small Cold to a Large Hot Bed for Biomass Conversion in a Bubbling Fluidized Bed Reactor

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