Numerical simulations of single phase reacting flows in randomly packed fixed-bed reactors and experimental validation

Freund, Hannsjörg; Zeiser, Thomas; Huber, Florian; Klemm, Elias; Brenner, Günther; Durst, F.; Emig, G.

doi:10.1016/s0009-2509(02)00622-x

Cited by 206 publications

(95 citation statements)

References 19 publications

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“…The most universal method from a mathematical point of view is FEM [83,84] Very different from those three methods are the Lattice-Boltzmann methods (LBM) [85] , which have recently become popular in particular for the simulation of complex flow structures found in fixed beds [86][87][88] . The LBM may be considered as a finite difference method for a discrete Boltzmann equation.…”

Section: Numerical Methods For the Solution Of The Governing Equationsmentioning

confidence: 99%

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Computational Fluid Dynamics Simulation of Catalytic Reactors

Deutschmann

2008

Handbook of Heterogeneous Catalysis

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Catalytic reactors are generally characterized by the complex interaction of various physical and chemical processes. Monolithic reactors can serve as example, in which partial oxidation and reforming of hydrocarbons, combustion of natural gas, and the reduction of pollutant emissions from automobiles are frequently carried out. Figure 1 illustrates the physics and chemistry in a catalytic combustion monolith that glows at a temperature of about 1300 K due to the exothermic oxidation reactions. In each channel of the monolith, the transport of momentum, energy, and chemical species occurs not only in flow (axial) direction, but also in radial direction. The reactants diffuse to the inner channel wall, which is coated with the catalytic material, where the gaseous species adsorb and react on the surface. The products and intermediates desorb and diffuse back into the bulk flow. Due to the high temperatures, the chemical species may also react homogeneously in the gas phase. In catalytic reactors, the catalyst material is often dispersed in porous structures like washcoats or pellets. Mass transport in the fluid phase and chemical reactions are then superimposed by diffusion of the species to the active catalytic centers in the pores. The temperature distribution depends on the interaction of heat convection and conduction in the fluid, heat release due to chemical reactions, heat transport in the solid material, and thermal radiation. If the feed conditions vary in time and space and/or heat transfer occurs between the reactor and the ambience, a non-uniform temperature distribution over the entire monolith will result, and the behavior will differ from channel to channel.Today, the challenge in catalysis is not only the development of new catalysts to synthesize a desired product, but also the understanding of the interaction of the catalyst with the surrounding reactive flow field. Sometimes, the exploitation of these interactions can lead to

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Section: Numerical Methods For the Solution Of The Governing Equationsmentioning

confidence: 99%

“…Recently, Lattice-Boltzmann-methods (LBM) have been applied for a better understanding of fluid flow in complex reactor configurations [87,88,134] . The packing of spheres in cylindrical columns can be created either from experimental observations, such as magnetic resonance imaging (MRI), or by computer simulations.…”

Section: Fixed Bed Reactorsmentioning

confidence: 99%

Computational Fluid Dynamics Simulation of Catalytic Reactors

Deutschmann

2008

Handbook of Heterogeneous Catalysis

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“…Alternative concepts such as Lattice-Boltzmann models (LBM) [39,40] are still difficult to handle in multi-component mixtures but are promising for the simulation of complex flow structures for instance in fixed beds [41][42][43]; they will not be covered here.…”

Section: Governing Equations For Multi-componentmentioning

confidence: 99%

“…9) [111]. Lattice-Boltzmann-methods (LBM) have also been applied for a better understanding of fluid flow in complex reactor configurations [42,43,112]. The packing of spheres in cylindrical columns can be created either from experimental observations, such as magnetic resonance imaging (MRI), or by computer simulations.…”

Section: Complex Flows Structures: Catalytic Fixed Bed Reactorsmentioning

confidence: 99%

Modeling of the Interactions Between Catalytic Surfaces and Gas-Phase

Deutschmann

2014

Catal Lett

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The catalytic surface interacts with the gasphase by a variety of chemical and physical processes. Hence, optimization of design and operation conditions of catalytic reactors do not only require the understanding of the catalytic reaction sequence but also its coupling with mass and heat transport and potential homogeneous reactions. The chemical, thermal, and mass-transport interactions between the catalytic surface and the gas-phase are discussed in terms of the individual and combined interactions. The state-of-the-art modelling of reactive flows and its coupling with the catalytic surface is summarized. The interactions are illustrated by a number of examples such as reforming of hydrocarbons, catalytic combustion, exhaust-gas after-treatment, each focusing on a special aspect of catalyst-gas interactions. The potentials and limitations of the numerical simulations will be discussed including experimental techniques for model validation.

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“…Dixon et al (2003) coupled heat transfer with gas flow by giving a heat flux on particles according to reac-tion rates in the literature. Freund et al (2003) solved first flow field and subsequently mass transport with a simple reaction by fixing the flow field. Recently, Dixon et al (2007) performed a fully coupled simulation with intraparticle MSR reactions in the 120 • wall segment model consisting of 8 spheres within 2 layers.…”

Section: Introductionmentioning

confidence: 99%

A High-Fidelity CFD Model of Methane Steam Reforming in a Packed Bed Reactor

Kuroki

Ookawara

Ogawa

2009

J. Chem. Eng. Japan / JCEJ

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A novel high-fidelity CFD model is proposed for the process optimization and intensification of methane steam reforming in a packed bed reactor. The random packing of spherical particles is constituted by simulating a dumping of particles into the annular reactor by a commercial code based on discrete element method (DEM). The complex spatial geometry between hundreds of particles is created associated with a developed interparticle bridge method, which eliminates the interparticle and particle-wall contact regions by assuming that the small regions are stagnant and would not affect the reactor behavior. The conservation equations of mass, momentum, energy and chemical species are fully solved by employing a commercial CFD code based on finite volume method. A newly coded subroutine is incorporated into the CFD code to evaluate the reaction rates according to the species partial pressures and temperature on each surface cell covering the particles. The values of reaction, equilibrium and adsorption constants are specified based on the experiments in the literature. According to the reaction rates, the mass and heat sources are given to each fluid cell on the surface cell. It is verified that the developed CFD model is capable of predicting the distributions of species and temperature microscopically as well as macroscopically for methane steam reforming. The present DEM-CFD procedure enables one to investigate the behavior of packed bed reactor in detail once the catalyst is characterized in a conventional way. Therefore it would become a powerful tool to optimize and intensify any process in a packed bed reactor where the plug flow assumption is invalid.

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Numerical simulations of single phase reacting flows in randomly packed fixed-bed reactors and experimental validation

Cited by 206 publications

References 19 publications

Computational Fluid Dynamics Simulation of Catalytic Reactors

Computational Fluid Dynamics Simulation of Catalytic Reactors

Modeling of the Interactions Between Catalytic Surfaces and Gas-Phase

A High-Fidelity CFD Model of Methane Steam Reforming in a Packed Bed Reactor

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