Evaluating EMMS Model for Simulating High Solid Flux Risers

Naren, P. R.; Lali, Arvind; Ranade, Vivek V.

doi:10.1205/cherd06077

Cited by 31 publications

(11 citation statements)

References 29 publications

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“… 41 − 43 Although some of the EMMS-based computational studies account for clustering phenomena, simplifying assumptions are made. Some of these are (1) clusters have a uniform density, equal to maximum packing fraction 44 and (2) clusters are spherical structures that interact with a lean surrounding phase and are homogeneously dispersed in a control volume. 45 Some of these computational studies have suggested that global scale mass-transfer resistances are related to cluster formation.…”

Section: Introductionmentioning

confidence: 99%

Computational Fluid Dynamics–Discrete Element Method (CFD-DEM) Study of Mass-Transfer Mechanisms in Riser Flow

Varas

Peters

Kuipers

2017

Ind. Eng. Chem. Res.

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We report a computational fluid dynamics–discrete element method (CFD-DEM) simulation study on the interplay between mass transfer and a heterogeneous catalyzed chemical reaction in cocurrent gas-particle flows as encountered in risers. Slip velocity, axial gas dispersion, gas bypassing, and particle mixing phenomena have been evaluated under riser flow conditions to study the complex system behavior in detail. The most important factors are found to be directly related to particle cluster formation. Low air-to-solids flux ratios lead to more heterogeneous systems, where the cluster formation is more pronounced and mass transfer more influenced. Falling clusters can be partially circumvented by the gas phase, which therefore does not fully interact with the cluster particles, leading to poor gas–solid contact efficiencies. Cluster gas–solid contact efficiencies are quantified at several gas superficial velocities, reaction rates, and dilution factors in order to gain more insight regarding the influence of clustering phenomena on the performance of riser reactors.

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Section: Introductionmentioning

confidence: 99%

Computational Fluid Dynamics–Discrete Element Method (CFD-DEM) Study of Mass-Transfer Mechanisms in Riser Flow

Varas

Peters

Kuipers

2017

Ind. Eng. Chem. Res.

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“…Table 1 summarizes important characteristics of the used uniform meshes, whereas in Table 2 the main gas/solid properties are presented. It should be mentioned that Geldart B type particles are investigated (as in the work of Wang et al, 2008) in contrast to the majority of the researchers who investigated Geldart A (Zhang et al, 2008;Wang and Li, 2007;Chalermsinsuwan et al, 2009aChalermsinsuwan et al, , 2009bNaren et al, 2007;Wang, 2008;Yan et al, 2002). Geldart (1973) 2003) were used.…”

Section: Numerical Detailsmentioning

confidence: 99%

An advanced EMMS scheme for the prediction of drag coefficient under a 1.2MWth CFBC isothermal flow—Part II: Numerical implementation

Nikolopoulos

Ατσόνιος

Νikolopoulos

et al. 2010

Chemical Engineering Science

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“…The solid particles fluid-like state provide excellent heat and mass transfer characteristic and circulation of solid offer operational flexibility [2,3]. The CFB riser section serves as the main reaction zone, in which strands of particles (clusters) influence the flow and the performance of reactor [4]. Over the years, considerable effort has been made to better design and operation of CFB reactor.…”

Section: Introductionmentioning

confidence: 99%

An Assessment of Drag Models in Eulerian–Eulerian CFD Simulation of Gas–Solid Flow Hydrodynamics in Circulating Fluidized Bed Riser

Upadhyay

Kim

et al. 2020

ChemEngineering

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Accurate prediction of the hydrodynamic profile is important for circulating fluidized bed (CFB) reactor design and scale-up. Multiphase computational fluid dynamics (CFD) simulation with interphase momentum exchange is key to accurately predict the gas-solid profile along the height of the riser. The present work deals with the assessment of six different drag model capability to accurately predict the riser section axial solid holdup distribution in bench scale circulating fluidized bed. The difference between six drag model predictions were validated against the experiment data. Two-dimensional geometry, transient solver and Eulerian–Eulerian multiphase models were used. Six drag model simulation predictions were discussed with respect to axial and radial profile. The comparison between CFD simulation and experimental data shows that the Syamlal-O’Brien, Gidaspow, Wen-Yu and Huilin-Gidaspow drag models were successfully able to predict the riser upper section solid holdup distribution with better accuracy, however unable to predict the solid holdup transition region. On the other hand, the Gibilaro model and Helland drag model were successfully able to predict the bottom dense region, but the upper section solid holdup distribution was overpredicted. The CFD simulation comparison of different drag model has clearly shown the limitation of the drag model to accurately predict overall axial heterogeneity with accuracy.

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Evaluating EMMS Model for Simulating High Solid Flux Risers

Cited by 31 publications

References 29 publications

Computational Fluid Dynamics–Discrete Element Method (CFD-DEM) Study of Mass-Transfer Mechanisms in Riser Flow

Computational Fluid Dynamics–Discrete Element Method (CFD-DEM) Study of Mass-Transfer Mechanisms in Riser Flow

An advanced EMMS scheme for the prediction of drag coefficient under a 1.2MWth CFBC isothermal flow—Part II: Numerical implementation

An Assessment of Drag Models in Eulerian–Eulerian CFD Simulation of Gas–Solid Flow Hydrodynamics in Circulating Fluidized Bed Riser

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