Modeling fixed-bed reactors from metal-foam pellets with detailed CFD

Wehinger, Gregor D.; Kolaczkowski, S.T.; Schmalhorst, Leonhard; Beton, Didier; Torkuhl, Lars

doi:10.1016/j.cej.2019.05.067

Cited by 29 publications

(10 citation statements)

References 44 publications

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“…---Qian et al [216] Cylinder 0.5-5 ->10 16 --Zou and Yu [241] Cylinder 1-100 -4-40 > 10 --Montillet and Coq [115] Cylinder Wehinger et al [268] Hexagons…”

Section: --mentioning

confidence: 99%

Review on the structure of random packed‐beds

Seckendorff

Hinrichsen

2021

Can J Chem Eng

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Independent from their intended purpose, the understanding of structural characteristics of random packings of particles having defined shapes is important to understand and optimize fluid dynamic behaviour, heat, and mass transfer. The packing structure can be described by the coordination number, local porosity profiles, the average porosity, and pore characteristics, which are influenced by the wall and thickness effect; the material, shape, and size distribution of the packing particles; the packing and compaction mode; and the shape and material of the packing's containing walls. Therefore, existing knowledge on the structure of randomly packed mono-sized particles is reviewed to provide an updated selection of relevant parameters and their derived correlations obtained by experimental, numerical, and analytical means.packed-bed reactor, porosity, random particle packings, review, structure | INTRODUCTIONRandom packings of particles having defined shapes are deployed in all kinds of industrial applications and come in all orders of magnitude. The most prominent examples comprise micro-sized particle beds as commonly used in chromatography packed columns, [1][2][3] packed-bed reactors filled with catalytic shaped bodies having millimetre size, [4,5] packed columns used in separation processes such as distillation incorporating particles in the lower centimetre range, [6,7] and the pebble-bed reactor, which is a gas-cooled nuclear reactor, moderated by a packing of graphite spheres. [8][9][10] In addition to those, numerous less-known applications of packed-beds exist, ranging from powder-bed 3D printers, [11] solar-energy storage systems, [12] earth science, [13] civil engineering, [14,15] and pharmaceutical processing, [16] to the pyrolysis of pelletized wood fuels, [17] to name but a few.Irrespective of its intended purpose, the extent of a packed-bed is limited by a confining wall of commonly cylindrical shape, though flat plates and other container geometries are possible. Despite its generally random nature, close to this confinement the particles' placement is naturally forced to align with the wall's geometry. This imposed order reaches a couple of particle diameters into the packing and is usually named the wall effect. Its influence on the overall packed-bed characteristics decreases with increasing tube-to-particle diameter ratio λ = D d p . While most applications operate in an only sparsely affected λ-range, this effect becomes dominant, for instance, in catalytic multitubular reactors, typically performing at λ = 4-7 [18] or a single-pellet-string reactor with a λ < 2. [19] Moreover, some packed-bed utilizations, especially chromatography columns, have very delicate requirements regarding bed homogeneity and its derived characteristics.Abbreviations: DEM, discrete element method; Erfc, error function; J 0 , Bessel function of first kind and zero order; MRJ, maximally random jammed; RCP, random close packing; RLP, random loose packing.

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“…---Qian et al [216] Cylinder 0.5-5 ->10 16 --Zou and Yu [241] Cylinder 1-100 -4-40 > 10 --Montillet and Coq [115] Cylinder Wehinger et al [268] Hexagons…”

Section: --mentioning

confidence: 99%

Review on the structure of random packed‐beds

Seckendorff

Hinrichsen

2021

Can J Chem Eng

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“…To address these kinds of problems, multiscale modeling approaches need to be adopted. Recently, Wehinger et al 36 have presented a CFD approach, in which the established particle‐resolved CFD model is integrated with pseudo‐homogeneous porous medium model to account for the transport phenomena inside the foam pellets. The authors used DEM approach to generate the fixed‐bed structure.…”

Section: Introductionmentioning

confidence: 99%

“…In this work, a workflow for an adapted particle-resolved CFD approach is presented to study the flow characteristics in the fixedbed made of metal foam pellets and validate it against the experimental data of bed voidage and pressure drop. The proposed CFD workflow is similar to Wehinger et al 36 ; instead of DEM, RBD approach generates the different fixed-bed structures. The inclusion of RBD approach provides more flexibility to model the packing structures with any arbitrary catalyst particle shapes and even allows mimicking the catalyst loading strategies akin to commercial settings, with F I G U R E 1 Metal foam pellets manufactured by Alantum Europe GmbH, Germany low computational efforts.…”

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confidence: 99%

Workflow for computational fluid dynamics modeling of fixed‐bed reactors packed with metal foam pellets: Hydrodynamics

George

Bockelmann

Schmalhorst³

et al. 2021

AIChE Journal

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In recent years, the catalyst pellets made of open‐cell metallic foams have been identified as a promising alternative in fixed‐bed reactors. A reliable modeling tool is necessary to investigate the suitability of different foam properties and the shapes of foam pellets. In this article, a workflow for a detailed computational fluid dynamics (CFD) model is presented, which aims to study the flow characteristics in the slender packed beds made of metal foam pellets. The CFD model accounts for the actual random packing structure and the fluid flow throughout the interstitial regions is fully resolved, whereas flow through the porous foam pellets is represented by the closure equations for the porous media model. The bed structure is generated using rigid body dynamics (RBD) and the influence of the catalyst loading method is also considered. The mean bed voidage and the pressure drop predicted by the simulations show good agreement with the experimental data.

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“…Ein interessanter Ansatz, um synthetische Schaumstrukturen zu erzeugen und mit anschließenden CFD-Simulationen zu untersuchten, wurde anhand der Partialoxidation von Methan vorgestellt [21]. In Zusammenarbeit mit der Firma Alantum wird in meiner Arbeitsgruppe in einem ZIM-Projekt der Einsatz von Schaumpellets in Festbettreaktoren mit CFD-Simulationen untersucht [22,23] (s. Abb. 5).…”

Section: Festbettreaktorenunclassified

Young Scientists – Juniorprofessor Gregor D. Wehinger stellt sich vor

Wehinger

2021

Chemie Ingenieur Technik

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In diesem Beitrag stellt sich Juniorprofessor Gregor D. Wehinger vom Institut für Chemische und Elektrochemische Verfahrenstechnik der TU Clausthal vor. Neben aktuellen Forschungsarbeiten und Lehraktivitäten gibt er auch einen Ü berblick darüber, wie er sich in der Community engagiert. Fachlich berichtet er von aktuellen Ergebnissen im Bereich der CFD-Modellierung von Festbettreaktoren, Redox-Flow-Batterien und Mehrphasensystemen. Zudem wird der Einsatz von virtueller Realität in einem aktuellen Lehrprojekt vorgestellt.

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Modeling fixed-bed reactors from metal-foam pellets with detailed CFD

Cited by 29 publications

References 44 publications

Review on the structure of random packed‐beds

Review on the structure of random packed‐beds

Workflow for computational fluid dynamics modeling of fixed‐bed reactors packed with metal foam pellets: Hydrodynamics

Young Scientists – Juniorprofessor Gregor D. Wehinger stellt sich vor

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