Optimization of gas–liquid reactor using computational fluid dynamics

A critical review of the published literature regarding the computational fluid dynamics (CFD) modelling of single-phase turbulent flow in stirred tank reactors is presented. In this part of review, CFD simulations of radial flow impellers (mainly disc turbine (DT)) in a fully baffled vessel operating in a turbulent regime have been presented. Simulated results obtained with different impeller modelling approaches (impeller boundary condition, multiple reference frame, computational snap shot and the sliding mesh approaches) and different turbulence models (standard k − ε model, RNG k − ε model, the Reynolds stress model (RSM) and large eddy simulation) have been compared with the in-house laser Doppler anemometry (LDA) experimental data. In addition, recently proposed modifications to the standard k − ε models were also evaluated. The model predictions (of all the mean velocities, turbulent kinetic energy and its dissipation rate) have been compared with the experimental measurements at various locations in the tank. A discussion is presented to highlight strengths and weaknesses of currently used CFD models. A preliminary analysis of sensitivity of modelling assumptions in the k − ε models and RSM has been carried out using LES database. The quantitative comparison of exact and modelled turbulence production, transport and dissipation terms has highlighted the reasons behind the partial success of various modifications of standard k − ε model as well as RSM. The volume integral of predicted energy dissipation rate is compared with the energy input rate. Based on these results, suggestions have been made for the future work in this area.Nous présentons un examen critique de la littérature concernant la modélisation de la dynamique des fluides numérique (DFN) de l'écoulement turbulentà une phase dans les réacteursà cuve agitée. Dans cette partie de l'examen, nous présentons les simulations de DFN de turbinesà ecoulement radial (principalement des turbinesà disque (TD)) dans un réservoir entièrement cloisonné effectuées dans un régime turbulent. Les résultats des simulations obtenus grâceà différentes approches de modélisation des turbines (couche limite turbulente, méthode des référentiels multiples, snap-shot de modélisation numérique, maillage glissant) età différents modèles de turbulence (modèle standard k-e, modèle RNG k-e, modèle aux tensions de Reynolds et simulation des grandeséchelles) ontété comparés aux données expérimentales internes d'allocation de Dirichlet latente (ADL). De plus, les modifications des modèles standards k-e récemment proposées ontégalementétéévaluées. Les prédictions du modèle (de toutes les vitesses moyennes, de l'énergie cinétique turbulente et de son taux de dissipation) ontété comparées aux données expérimentales relevéesà différents endroits de la cuve. Une discussion présente les points forts et les points faibles des modèles de DFN actuellement utilisés. Une analyse préliminaire de la sensibilité des hypothèses de modélisation liées aux modèles k-e et RSM aété menée en utilis...

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“…Komasawa et al (1970); Robinson and Wilke (1973); Uchida et al (1978); Leszek et al (2004); Patwardhan et al (2005); Milewska and Molga (2010)…”

Section: Introductionmentioning

confidence: 99%

CFD simulation of stirred tanks: Comparison of turbulence models. Part I: Radial flow impellers

et al. 2011

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“…Computational models have also been extensively used for intensifying reactions in stirred tank reactors. , One example is cited here: Patwardhan et al simulated a large industrial oxidation reactor using CFD. The CFD model gave an adequately accurate prediction of the residence time distribution of the industrial-scale reactor.…”

Section: Tools and Examples Of Intensification Of Multiphase Reaction...mentioning

confidence: 99%

Intensifying Multiphase Reactions and Reactors: Strategies and Examples

Utikar

Ranade²

2017

ACS Sustainable Chem. Eng.

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Intensification is intrinsic to better chemical and process engineering and has always been used in practice. Multiphase reactions and reactors are ubiquitous in chemical and allied industries and are of great economic and ecological importance. There is a great scope for intensifying multiphase reactions and reactors for realizing productivity enhancements, which are crucial for sustainable manufacturing. These enhancements can be in terms of increased throughput; better yield, conversion, and selectivity; smaller environmental footprint; and intrinsically safer operations. The advances in intensified reactors especially micro-reactors and microfluidic devices have created significant awareness about intensification in recent decades. In this note, we discuss different strategies for intensifying multiphase reactions and reactors based on the published information. Variety of tools and examples are presented to showcase the potential of intensification. We have found the efforts towards intensification of multiphase reactions and reactors very rewarding academically as well as professionally. We hope that this note will further stimulate interest in this area and pave the way towards realizing next generation productivity for chemical and allied industries.

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“…CFD tools have been applied in different kinds of reactor and bioreactor simulations. For example, Patwardhan et al [1] studied the relationship between geometry and operating conditions of an industrial gasliquid stirred reactor and had a good prediction of the residence time distribution of the industrial scale reactor. CFD tools were applied to perform stirred solidliquid reactors [3].…”

Section: Introductionmentioning

confidence: 99%

Design optimization of a bioreactor for ethanol production using CFD simulation and genetic algorithms

Góis

Seleghim

2011

Computational Methods and Experimental Measurements XV

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The increase of the use of biofuels, like bioethanol, has presented new challenges to engineering problems. The optimization of bioreactors is crucial to improve the bioethanol extraction and to avoid stagnant zones in the flow that can compromise the chemical reactions involved in the process. This paper presents a solution using Computational Fluid Dynamics tools coupled with Genetics Algorithm to find an improved reactor structure. The preliminary results show that the influence of the height outlet tube alone is able to modify completely the flow pattern inside the reactor, improving the efficiency of the reactor.

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Optimization of gas–liquid reactor using computational fluid dynamics

Cited by 10 publications

References 8 publications

CFD simulation of stirred tanks: Comparison of turbulence models. Part I: Radial flow impellers

CFD simulation of stirred tanks: Comparison of turbulence models. Part I: Radial flow impellers

Intensifying Multiphase Reactions and Reactors: Strategies and Examples

Design optimization of a bioreactor for ethanol production using CFD simulation and genetic algorithms

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