Multicompartment hydrodynamic model for slurry bubble columns

Iliuta, Ion; Larachi, Faı ̈çal; Desvigne, Damien; Anfray, Jérôme; Dromard, Nicolas; Schweich, D.

doi:10.1016/j.ces.2008.03.040

Cited by 11 publications

(9 citation statements)

References 20 publications

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“…It should be mentioned that the two-bubble class model in conjunction with the axial dispersion model has been accepted and used to model bubbles behavior in SBCRs [195,196,198,200,[234][235][236][237]. In this model, the churn turbulent flow regime was assumed where large bubbles rise straight up through the reactor without recirculation, while small bubbles with lower rise velocity were entrained in the liquid and as such they followed the liquid-phase backmixing behavior.…”

Section: Haberman and Morton []mentioning

confidence: 99%

“…This approach gives rise to inaccuracies and deviations since it is only concerned with the limiting cases, while the actual extent of the interaction between the large and small gas bubbles would occur somewhere in the middle, which would create some differences in species concentration [199]. Moreover, intra-phase backmixing has either been accounted for using perfect mixing or by assuming plug flow [200], however, non-ideal flow models, accounting for a finite degree of backmixing, are believed to be more realistic. There are two basic categories of non-ideal flow models, axial dispersion models and multi-cell models.…”

Section: Wilkinson and Van Dierendonck []mentioning

confidence: 99%

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Fischer–Tropsch Synthesis in Slurry Bubble Column Reactors: Experimental Investigations and Modeling – A Review

Basha

Sehabiague

Abdel‐Wahab

et al. 2015

International Journal of Chemical Reactor Engineering

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This paper presents an extensive review of the kinetics, hydrodynamics, mass transfer, heat transfer and mathematical as well as computational fluid dynamics (CFD) modeling of Low-Temperature Tropsch Synthesis (LTFT) synthesis in Slurry Bubble Column Reactors (SBCRs), with the aim of identifying potential research and development areas in this particular field. The kinetic expressions developed for F-T synthesis over iron and cobalt catalysts along with the water gas shift (WGS) reactions are summarized and compared. The experimental data and empirical correlations to predict the hydrodynamics (gas holdup, Sauter mean bubble diameter, and bubble rise velocity), mass transfer coefficients and heat transfer coefficients are presented. The effects of various operating variables, including pressure, temperature, gas velocity, catalyst concentration, reactor geometry, and reactor internals on the hydrodynamic and transport parameters as well as the performance of SBCRs are discussed. Additionally, modeling efforts of SBCRs, using axial dispersion models (ADM), multiple cell recirculation models (MCCM) and computational fluid dynamics (CFD), are addressed. This review revealed the following:(1) Numerous F-T and WGS kinetic rate expressions are available for cobalt and iron catalysts and one must be careful in selecting the appropriate expressions for LTFT. Iron catalyst suffers from severe attrition and subsequent deactivation in SBCRs and accordingly building a costly catalyst manufacturing facility onsite is required to maintain a steady operation of the F-T reactor;(2) Experimental data on the hydrodynamic and transport parameters at high pressures and temperatures, typical to those of actual F-T synthesis, remain scanty when compared with the plethora of studies conducted using air-water systems in small reactors at ambient conditions; (3) Several empirical correlations for predicting the hydrodynamic and mass as well heat transfer parameters are available and one should select those which consider the reactor diameter, gas mixtures and the potential foamability of the F-T liquids; (4) The effect of cooling internals configuration and sparger design on the hydrodynamic and transport parameters, local turbulence, mixing and catalyst attrition are yet to be seriously addressed; (5) The impact of operating variables on the hydrodynamic and transport parameters as well as the overall performance of the SBCRs should be investigated using actual F-T fluid-solid systems under typical pressures and temperatures using a large-scale reactor ( > 0.15 m ID) in the presence of gas spargers and cooling internals; (6) Significant efforts are still required in order to advance CFD modeling of SBCRs, particularly those pertaining to the relevant closure models, such as drag, lift and turbulence. Also, cooling internals configuration and the design as well as orientation of gas spargers should be accounted for in the CFD modeling; and (7) Proper validations of the CFD formulations using actual systems for F-T SBCR are needed.

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Section: Haberman and Morton []mentioning

confidence: 99%

Section: Wilkinson and Van Dierendonck []mentioning

confidence: 99%

Fischer–Tropsch Synthesis in Slurry Bubble Column Reactors: Experimental Investigations and Modeling – A Review

Basha

Sehabiague

Abdel‐Wahab

et al. 2015

International Journal of Chemical Reactor Engineering

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“…Auch eine bessere Beschreibung der Austauschoberfläche und somit des Stoffübergangs zwischen Gas-und Flüssigphase lässt sich so erreichen [25]. Hierbei werden die Großblasen mit nur einem nach oben strömendem Kompartment modelliert, während die Kleinblasen rezirkulieren können.…”

Section: Abbildung 2 Exemplarische Auswahl Von Shortcut-modelle Fürunclassified

“…Hierbei werden die Großblasen mit nur einem nach oben strömendem Kompartment modelliert, während die Kleinblasen rezirkulieren können. Auch eine bessere Beschreibung der Austauschoberfläche und somit des Stoffübergangs zwischen Gas-und Flüssigphase lässt sich so erreichen [25].…”

Section: Abbildung 2 Exemplarische Auswahl Von Shortcut-modelle Fürunclassified

Simulation of Bubble Columns with a Compartment Model Approach

Abel

Schlusemann

Grünewald

2013

Chemie Ingenieur Technik

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Blasensäulenreaktoren sind zwar mechanisch einfache Apparate, die in ihnen vorherrschenden Gas-Flüssig-Interaktionen sind aber bedeutend komplexer. Die Auslegung anhand des axialen Dispersionsmodells hat entscheidende Nachteile in der Beschreibung der komplexen Wechselwirkungen zwischen Gas-und Flüssigphase. Obwohl die numerische Strömungsmechanik in den letzten Jahren, auch aufgrund steigender Rechnerkapazitäten und -leistungen, sehr vielversprechende Fortschritte gemacht hat, ist die Berechnung des Betriebsverhaltens industrieller Blasensäulenreaktoren nicht verifizierbar. Als Alternative bieten sich eine Unterteilung des Reaktors in Teilbilanzräume an. Diese als Kompartment-Modellierung bekannte Beschreibungsmethode wird im Rahmen des Beitrags erläutert und diskutiert.Bubble column reactors are mechanical simple apparatuses, but the interactions between the liquid and gas phases have proven to be more complex. The description with an axial dispersion model has significantly disadvantages describing those physical phenomena. Although numerical fluid dynamics promising progress, not only backed by the increase in computational power and capacities, these calculations are not yet verifiable for industry sized reactors. An alternative approach is to divide the reactor in smaller material balance envelopes. This approach, known as compartment modeling, is explained and discussed in this article. Abbildung 4. Vergleich zwischen CBC-(links) und LBL-Agglomeration (rechts) [27]. Abbildung 5. Exemplarische Ergebnisse einer CBC-Agglomeration auf Grundlage einer Strömungssimulation (links: axiale Flüssigkeitsgeschwindigkeit (von schwarz nach weiß), rechts: schwarze Linien stellen die Kompartmentgrenzen dar).

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“…On the basis of using the DGD technique, various authors ,,, observed that the large gas bubbles move quickly upward through the slurry in a plug-flow manner, whereas, the small gas bubbles move slowly and are often entrained within the slurry-phase. This finding led to the development of the “two-bubble” or “bimodal” class model, which has been widely used to represent the gas bubbles in the convective and dispersive flow schemes within SBCRs , in one-dimensional (1-D) and two-dimensional (2-D) modeling of multiphase reactors. ,, …”

Section: Introductionmentioning

confidence: 99%

Novel Approach and Correlation for Bubble Size Distribution in a Slurry Bubble Column Reactor Operating in the Churn–Turbulent Flow Regime

Basha

Morsi

2018

Ind. Eng. Chem. Res.

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A novel approach to obtain bubble size distributions and Sauter mean bubble diameters (d 32 ) in three-phase slurry bubble column reactors (SBCRs) is presented. This approach is based on 720 experimental runs using the dynamic gas disengagement (DGD) technique for various gas−liquid−solid systems inside a pilot-scale-SBCR (0.3 m i.d./3 m height), in a wide range of pressures (1−30 bar), temperatures (298−530 K) and solid concentrations (0−17 vol %). The bubble size distributions were obtained using an iterative energy balance algorithm based on transient experimental pressure drops and forces exerted on bubbles in the disengagement cell. Bubble size distributions were described using log-normal distribution functions and the mean and variance were determined for the DGD runs. The mean and variance were correlated as functions of the system's physical properties and operating conditions, and were used to predict d 32 values with an absolute average relative error (AARE) of 11.72%. The approach was also applied to d 32 values available in the literature with an overall AARE of 24.27%.

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Multicompartment hydrodynamic model for slurry bubble columns

Cited by 11 publications

References 20 publications

Fischer–Tropsch Synthesis in Slurry Bubble Column Reactors: Experimental Investigations and Modeling – A Review

Fischer–Tropsch Synthesis in Slurry Bubble Column Reactors: Experimental Investigations and Modeling – A Review

Simulation of Bubble Columns with a Compartment Model Approach

Novel Approach and Correlation for Bubble Size Distribution in a Slurry Bubble Column Reactor Operating in the Churn–Turbulent Flow Regime

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