CFD as a Design Tool for Fixed-Bed Reactors

Dixon, Anthony G.; Nijemeisland, Michiel

doi:10.1021/ie001035a

Cited by 210 publications

(108 citation statements)

References 59 publications

(84 reference statements)

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“…In reality, the flow is seldom one-dimensional and a number of experimental studies have been conducted to determine the radial velocity profile and the effective radial thermal conductivity. Recently, several CFD and multi-physics simulations based upon the Navier Stokes equations have been used to more explicitly study these effects [10,5,16,4,15]. These studies have used as many as 30 million cells and required up to 11 hours of cpu time.…”

Section: Packed Bedsmentioning

confidence: 99%

A Study of the discrepancy function when modeling a packed bed using Variational Bayes and Gaussian processes

Sien

Emery

2018

J. Phys.: Conf. Ser.

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Abstract. Estimating properties using maximum likelihood (MLE) gives point values and a rough idea of the uncertainty in the parameters if their distributions are approximately normal. More accurate results require a Monte Carlo approach, often using the Markov Chain Monte Carlo (MCMC) method, which for complex models is unrealistic because of the computational expense. The Variational Bayes approach gives results comparable to MCMC with only a few evaluation of the model. When the model is imprecise or expensive to evaluate, Gaussian processes provide one means of analyzing the noise to determine the uncertainties.

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Section: Packed Bedsmentioning

confidence: 99%

A Study of the discrepancy function when modeling a packed bed using Variational Bayes and Gaussian processes

Sien

Emery

2018

J. Phys.: Conf. Ser.

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“…The effectiveness factor (η) is defined by Equation (1) and quantifies the effect intraparticle diffusion resistance has on reaction rate [35][36][37][38]. η = actual reaction rate reaction rate without diffusion limitations (1) The concept of effectiveness factor (η) in heterogeneous catalytic reactions for porous particles is given by Levenspiel [38].…”

Section: Thiele Modulus and Effectiveness Factormentioning

confidence: 99%

“…The advantages of such resolved simulations, commonly referred to as particle-resolved direct numerical simulations (PR-DNS), have been pointed out by [1]. Due to the homogeneous average voidage inside a typical packed bed, the resolved simulation of a small segment of the bed can give valuable insight into the local transport phenomena, applicable to the whole packed bed.…”

Section: Introductionmentioning

confidence: 99%

Verification of Heat and Mass Transfer Closures in Industrial Scale Packed Bed Reactor Simulations

et al. 2018

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Particle-resolved direct numerical simulation (PR-DNS) is known to provide an accurate detailed insight into the local flow phenomena in static particle arrays. Most PR-DNS studies in literature do not account for reactions taking place inside the porous particles. In this study, PR-DNS is performed for catalytic reactions inside the particles using the multifluid approach where all heat and mass transfer phenomena are directly resolved both inside and outside the particles. These simulation results are then used to verify existing 1D model closures from literature over a number of different reaction parameters including different reaction orders, multiple reactions and reactants, interacting reactions, and reactions involving gas volume generation/consumption inside the particle. Results clearly showed that several modifications to existing 1D model closures are required to reproduce PR-DNS results. The resulting enhanced 1D model was then used to accurately simulate steam methane reforming, which includes all of the aforementioned reaction complexities. The effect of multiple reactants was found to be the most influential in this case.

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“…Computational fluid dynamics (CFD) studies have shown that the flow profile in a complex geometry is highly correlated to the structural properties such as bulk and local porosities [16]. Furthermore, it was shown that in such structures heat and mass transfer patterns strongly follow the local velocity profile [17,18].…”

Section: Introductionmentioning

confidence: 99%

Resolved-Pore Simulation of CO Oxidation on Rh/Al2O3 in a Catalyst Layer

Partopour

Dixon

2017

ChemEngineering

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Abstract:Computational fluid dynamics (CFD) is coupled with reaction and transport in a micro-scale pellet simulation to study CO oxidation over Rh/Al 2 O 3 catalyst. The macro-pores are explicitly modeled to study the interaction of these phenomena in both the solid and fluid phases. A catalyst layer is computationally reconstructed using a distribution of alumina particles and a simple force model. The constructed geometry properties are validated using the existing data in the literature. A surface mesh is generated and modified for the geometry using the shrink-wrap method and the surface mesh is used to create a volumetric mesh for the CFD simulation. The local pressure and velocity profiles are studied and it is shown that extreme changes in velocity profile could be observed. Furthermore, the reaction and species contours show how fast reaction on the surface of the solid phase limits the transport of the reactants from the fluid to meso-and micro-porous solid structures and therefore limits the overall efficiency of the porous structure. Finally, the importance of using a bi-modal pore structure in the diffusion methods for reaction engineering models is discussed.

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CFD as a Design Tool for Fixed-Bed Reactors

Cited by 210 publications

References 59 publications

A Study of the discrepancy function when modeling a packed bed using Variational Bayes and Gaussian processes

A Study of the discrepancy function when modeling a packed bed using Variational Bayes and Gaussian processes

Verification of Heat and Mass Transfer Closures in Industrial Scale Packed Bed Reactor Simulations

Resolved-Pore Simulation of CO Oxidation on Rh/Al2O3 in a Catalyst Layer

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