Gas-Solids Contact Efficiency in the Entrance Region of a Co-Current Downflow Fluidized Bed (Downer)

Zhu, Jesse; Ma, Yingliang; Zhang, H.

doi:10.1205/026387699525909

Cited by 11 publications

(2 citation statements)

References 8 publications

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“…Para la validación del modelo implementado se utilizaron los datos y las condiciones experimentales reportadas por Zhang (1999Zhang ( , 2000. El autor realizó los experimentos en un reactor Downer de 10 m de longitud, 0,1 m de diámetro interno, utilizando partículas de catalizador FCC con diámetro medio de Sauter de 67 μm y densidad de partícula de 1.500 Kg/m 3 .…”

Section: Análisis De Resultadosunclassified

The fluid dynamics of a downer fluidised bed using a cluster-based approach (CBA)

Silva

Lisbôa²,

Velásquez³

2010

Ing. Inv.

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The fluid dynamics of a downer reactor were numerically resolved by adapting a mathematical conservation model. The mathematical model was based on the solid and fluid properties and physical characteristics using a cluster-based approach (CBA). Comparing the numerical results to the experimental data found in the literature indicated that the mathematical model could satisfactorily predict the experimental data. The mathematical simulation determined that there were three fluid dynamic areas in the downer reactor which were characterised by accelerated, slowed -down and fully-developed flow. The fully developed flow area in the downer decreased with increased gas surface speed keeping solid flux constant.

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Section: Análisis De Resultadosunclassified

The fluid dynamics of a downer fluidised bed using a cluster-based approach (CBA)

Silva

Lisbôa²,

Velásquez³

2010

Ing. Inv.

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“…Later on, Zhu et al [26] investigated the contact efficiency between gas and solids particles in the entrance region of a 9.3 m tall and…”

Section: Introductionmentioning

confidence: 99%

Computational study of particle distribution development in a cold-flow laboratory scale downer reactor

López-Montoya

Bustamante

Nieto-Londoño

et al. 2021

CT&F Cienc. Tecnol. Futuro

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The use of downer reactors (gas-solid co-current downward flow) in the Fluid Catalytic cracking (FCC) process for the upgrading of heavy crude oil into more valuable products has gradually become more common in the last decades. This kind of reactor is characterized by having homogeneous axial and radial flow structures, no back mixing, and shorter residence times as compared with the riser reactor type. Although downer reactors were introduced a long time ago, available information in literature about the multiphase hydrodynamic behavior at FCC industrial scale is scarce. Therefore, it is necessary to conduct experimental and computational studies to enhance the understanding of the hydrodynamics of two-phase co-current downward flow. The Computational Fluids Dynamics (CFD) software, Ansys Fluent, is used to study two-dimensional gas (air) and solid (catalyst particle) flow in a downer section of a cold-flow circulation fluidized bed (CFB) system at a laboratory scale. The implemented computational model is validated by comparing numerical results for solid velocity and volume fraction with measurements carried out on a CFB system using a fiber-optic probe laser velocimeter. According to numerical results obtained for different gas velocity and solid flux, flow development cannot only be estimated by considering solid axial velocity changes along the reactor; it is also necessary to take into account solid volume fraction axial variations as radial profiles can change even when velocity profiles are developed.

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Effect of distributor designs on the flow development in downer reactor

et al. 1999

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Gas-Solids Contact Efficiency in the Entrance Region of a Co-Current Downflow Fluidized Bed (Downer)

Cited by 11 publications

References 8 publications

The fluid dynamics of a downer fluidised bed using a cluster-based approach (CBA)

The fluid dynamics of a downer fluidised bed using a cluster-based approach (CBA)

Computational study of particle distribution development in a cold-flow laboratory scale downer reactor

Effect of distributor designs on the flow development in downer reactor

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