Experimental and theoretical analysis of the hydrodynamics in the riser of an external loop airlift reactor

Vial, Christophe; Poncin, Souhila; Wild, Gabriel; Midoux, N.

doi:10.1016/s0009-2509(02)00284-1

Cited by 74 publications

(78 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The axial velocity in the riser region shows greater fluctuation in the riser than those in the downcomer which is similar in trend with [14] study. Nevertheless, results obtained from the LDA is satisfactory within a ±0.01 m/s range of discrepancy between the repetitive results as recommended [15].…”

Section: Fluidsche 2017supporting

confidence: 53%

“…LDA has been successfully employed in stirred tanks and bubble columns to measure mean axial liquid velocity profiles despite the challenges of capturing accurate two-phase flow field [6,[9][10][11][12][13]. Though experimental using LDA as a measurement method in airlift reactors are still limited [14][15]. In addition, both global and local hydrodynamics measurements used to derive empirical correlations for scale-up purposes is accurate only for similar geometrical designs, operating conditions and liquid properties.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Experimental measurement and CFD simulation on the hydrodynamics of an internal-loop airlift reactor

2017

View full text Add to dashboard Cite

Abstract. This paper concerns with the experimental measurement and computational fluid dynamics simulation on local hydrodynamics of a gas-liquid internal-loop airlift reactor. The aim of this work is to study the sensitivity of the drag models and the significance of considering the lift force on the predictive accuracy of the simulation. The experimental analysis was carried out using laser Doppler anemometry at three different heights (i.e. Y = 0.20 m, 0.30 m and 0.38 m) across the riser and downcomer at volumetric flow rate of 0.30 m 3 /h to provide validation for the simulation results. A transient three-dimensional gasliquid internal-loop airlift reactor was carried out using FLUENT 16.2 by implementing the two-fluid model approach. The Eulerian-Eulerian multiphase and standard k-İ dispersed turbulence model were employed in this study. Results suggest that the spherical drag model performed poorly and that the drag model governed by Rayleigh-Taylor shows promising accuracy in the prediction of overall mean axial liquid velocity. On the other hand, the consideration of lift model shows slightly improvement in accuracy. These findings may serve as a guidance for future scale-up and design of airlift reactor studies

show abstract

Section: Fluidsche 2017supporting

confidence: 53%

Section: Introductionmentioning

confidence: 99%

Experimental measurement and CFD simulation on the hydrodynamics of an internal-loop airlift reactor

2017

View full text Add to dashboard Cite

show abstract

“…In the past, many researchers studied IALRs using computational fluid dynamics (CFD) for describing hydrodynamics and have achieved significant success, e.g., Mudde and van den Akker [8], Blazej et al [4], Vial et al [9], van Baten et al [10], and Wu and Merchuk [11]. Basically, two different modeling approaches are mostly used to simulate gas-liquid twophase flow, i.e., the Euler-Euler (E-E) approach and the EulerLagrange (E-L) approach.…”

Section: Introductionmentioning

confidence: 99%

3‐D Simulations of an Internal Airlift Loop Reactor using a Steady Two‐Fluid Model

Huang

Yang

et al. 2007

Chem Eng & Technol

View full text Add to dashboard Cite

Three-dimensional (3-D) simulations of an internal airlift loop reactor in a cylindrical reference frame are presented, which are based on a two-fluid model with a revised k-e turbulence model for two-phase bubbly flow. A steady state formulation is used with the purpose of time saving for cases with superficial gas velocity values as high as 0.12 m/s. Special 3-D treatment of the boundary conditions at the axis is undertaken to allow asymmetric gas-liquid flow. The simulation results are compared to the experimental data on average gas holdup, average liquid velocity in the riser and the downcomer, and good agreement is observed. The turbulent dispersion in the present two-fluid model has a strong effect on the gas holdup distribution and wall-peaking behavior is predicted. The CFD code developed has the potential to be applied as a tool for scaling up loop reactors.

show abstract

“…Joshi et al (1990) and Bendjaballah et al (1999) also noted that the resistance in the ELAR, and thereby W LD , and the geometry of the downcomer influenced the regime transitions. On the other hand, Vial et al (2002) reported that the hydrodynamic resistance had a minor influence on the regime transitions. As can be seen in Figures 2 and 3, added alcohol had a noticeable influence on the transition between regimes in both ELAR and ELAMR for the sinter plate and perforated plate.…”

Section: Hydrodynamic Regimesmentioning

confidence: 99%

“…A membrane module inserted in the downcomer represents hydrodynamic resistance to the liquid flow. Higher resistance in the ELAR leads to a decrease in the liquid velocity and an increase in the gas holdup (Bendjaballah et al, 1999;Cao et al, 2008;Merchuk and Stein, 1981;Pošarac, 1988;Verlaan et al, 1989;Vial et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamics of an external-loop airlift reactor with inserted membrane

Kojić

Popović

Tokic

et al. 2017

Braz. J. Chem. Eng.

View full text Add to dashboard Cite

-The objective of this study was to investigate the hydrodynamics of an external-loop airlift membrane reactor (ELAMR). The ELAMR was operated in two modes: without (mode A) and with bubbles in the downcomer (mode B), depending on the liquid level in the gas separator. The influence of the gas distributor's geometry and various alcohol solutions on the hydrodynamics of the ELAMR was studied. Results for the gas holdup and the downcomer liquid velocity are commented with respect to an external-loop airlift reactor of the same geometry but without the membrane in the downcomer (ELAR). Due to the presence of the membrane in the downcomer, acting as the local hydrodynamic resistance, the gas holdup in the riser of the ELAMR increases maximally by 16%, while the liquid velocity in the downcomer decreases up to 50%. The values of the gas holdup and liquid velocity predicted by the application of empirical power law correlations and a feed forward back propagation neural network (ANN) are in very good agreement with experimental values.

show abstract

Experimental and theoretical analysis of the hydrodynamics in the riser of an external loop airlift reactor

Cited by 74 publications

References 43 publications

Experimental measurement and CFD simulation on the hydrodynamics of an internal-loop airlift reactor

Experimental measurement and CFD simulation on the hydrodynamics of an internal-loop airlift reactor

3‐D Simulations of an Internal Airlift Loop Reactor using a Steady Two‐Fluid Model

Hydrodynamics of an external-loop airlift reactor with inserted membrane

Contact Info

Product

Resources

About