Liquid Mixing in a Bubble Column

2011 ◽  
Author(s):  
Naoki Shimada ◽  
Rina Saiki ◽  
Abhinav Dhar ◽  
Akio Tomiyama
Keyword(s):  
Bubble Column ◽  
Perforated Plate ◽  
Transient Behavior ◽  
Interface Tracking ◽  
Linear Superposition ◽  
Tracer Concentration ◽  
Two Phase ◽  
Bubble Column Reactors ◽  
Liquid Mixing ◽  
Column Design

In most of the bubble column design, it is assumed that liquid phase is well mixed and spatial distributions of molar concentrations for all components are uniform. However, there is liquid mixing in actual bubble column reactors. The performance of a bubble column strongly depends on the liquid mixing induced by bubbles in the column. Those assumptions therefore cause some errors in column optimum design. Only a few quantitative investigations have been carried out on two-phase turbulence and liquid mixing. In this study, numerical simulations for liquid mixing in a bubble column have been carried out and compared with experiments. The transient behavior of tracer concentration was measured for test columns of 0.3 m in diameter. The height of the columns was 1 m. Bubbles were supplied by using two types of spargers: ring spargers and a perforated plate. A hybrid method, NP2-3D, which is based on the combination of multi-fluid and interface tracking methods, was used to simulate the flow. In a two-phase turbulence model, linear superposition of bubble-induced turbulence and shear-induced turbulence was assumed. Numerical prediction could qualitatively describe the effects of column diameter and gas inlet on the liquid mixing in a column.

Effects of Sparger and Internals Designs on the Local Hydrodynamics in Slurry Bubble Column Reactors Operating under Typical Fischer-Tropsch Process Conditions - I

2017 ◽  
Vol 16 (3) ◽  
Author(s):  
Omar M Basha ◽  
Badie I Morsi
Keyword(s):  
Large Scale ◽  
Bubble Column ◽  
Perforated Plate ◽  
Pilot Scale ◽  
Cfd Modeling ◽  
Bubble Column Reactor ◽  
Process Conditions ◽  
Bubble Column Reactors ◽  
Slurry Bubble Column ◽  
Slurry Bubble Column Reactors

AbstractOur rigorously validated Computational Fluid Dynamics (CFD) model (Basha Omar, M., L. Weng, Z. Men, and I. Morsi Badie. 2016. “CFD Modeling with Experimental Validation of the Internal Hydrodynamics in a Pilot-Scale Slurry Bubble Column Reactor.”International Journal of Chemical Reactor Engineering14(2):599–619), was used to predict the effects of spargers design and internals configuration on the local hydrodynamics and flow structure in a pilot-scale (0.3-m ID) and a large-scale (10-m ID) Slurry Bubble Column Reactors (SBCRs), operating under Fisher-Tropsch (F-T) process conditions. In the pilot-scale SBCR without internals, the 6-arms spider created small/fast liquid recirculations in the vicinity of the sparger and slow/large liquid recirculations at about 1.2 times reactor diameter, whereas, the 3-concentric-rings and perforated plate spargers created slow/large recirculations throughout the reactor. In the pilot-scale SBCR with internals, spargers with downward-pointing orifices created larger Sauter mean bubble diameters (ds), leading to more effective solids suspension when compared with those with upward-pointing orifices. Also, 3-concentric-rings spargers resulted in larger Sauter mean bubble diameter values when compared with those of 6-arms spiders. In the large-scale SBCR provided with a large 3-concentric-rings sparger, the effects of vertical parallel and bundled internals on the local hydrodynamics and flow structures were predicted. Bundled internals led to slower and smaller liquid recirculations, smoother radial gas holdup profiles, larger average gas bubbles size, and smaller local gas holdups, when compared those predicted when using parallel internals.

Comparison of void fraction measurements using different techniques in two-phase flow bubble column reactors

2018 ◽  
Vol 102 ◽  
pp. 119-129 ◽  
Author(s):  
Freddy Hernandez-Alvarado ◽  
Simon Kleinbart ◽  
Dinesh V. Kalaga ◽  
Sanjoy Banerjee ◽  
Jyeshtharaj B. Joshi ◽  
...  
Keyword(s):  
Void Fraction ◽  
Two Phase Flow ◽  
Bubble Column ◽  
Phase Flow ◽  
Two Phase ◽  
Bubble Column Reactors

scholarly journals The Effect of Hydraulic Conditions in Barbotage Reactors on Aeration Efficiency

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 724
Author(s):  
Sebastian Kujawiak ◽  
Małgorzata Makowska ◽  
Jakub Mazurkiewicz
Keyword(s):  
Structural Design ◽  
Bubble Column ◽  
Hybrid Reactor ◽  
Two Phase ◽  
Moving Bed ◽  
External Loop ◽  
Bubble Column Reactors ◽  
Aeration Efficiency ◽  
Reactor Geometry ◽  
The Individual

Barbotage reactors such as airlift reactors (ALR) and bubble column reactors (BCR), due to their two-phase flow systems, were investigated in many research papers. In their basic design variants, they are typically used to lift, mix, and aerate liquids, while, when equipped with additional elements in hybrid variants, their individual properties, i.e., lifting, mixing, and aeration of liquids, can significantly change with the same reactor geometry. The object of this study was to develop a hybrid barbotage reactor in various structural design variants. The structure consisted of a barbotage column of 50 mm in diameter, used to transport a water–air mixture outside the reactor (so-called external loop). The installation was additionally equipped with a nozzle in order to improve mixture aeration and circulation efficiency. The nozzle was mounted at various heights of the column pump segment. Additionally, the reactor was equipped with s moving bed in two variants (20% and 40% reactor capacity) in order to determine its effect on the mixture aeration and circulation conditions. Based on the measurement results, aeration curves were prepared for various structural design and column packing variants of the reactor. Properties of the two-phase mixture were determined for both parts—ALR and BCR. Technological and energy parameters of the aeration process were calculated, and the results obtained for the individual structural design variants were compared. It was found that, for the most advantageous design, in terms of aeration efficiency, the aeration nozzle should be placed in the mid-length of the pump segment of the barbotage column, irrespective of the hybrid reactor packing rate with the moving bed. The reactor packing with the moving bed resulted in a decreased mean water velocity in the reactor. For most analyzed structural design variants, the respective packing with the moving bed had no significant effect on aeration efficiency. Only for one structural design variant did the lack of packing significantly improve oxygen levels by as much as approximately 41%.

Heat transfer metrology issues in two-phase bubble column reactors

2010 ◽  
pp. n/a-n/a
Author(s):  
Pierre-Emmanuel Béliard ◽  
Daniel Schweich ◽  
Patrice Clément ◽  
Paola Gauthier-Maradei ◽  
Nicolas Dromard
Keyword(s):  
Heat Transfer ◽  
Bubble Column ◽  
Two Phase ◽  
Bubble Column Reactors

Large Eddy Simulation of the Gas–Liquid Flow in a Cylindrical Cross-Sectioned Bubble Column

2012 ◽  
Vol 170-173 ◽  
pp. 2703-2707
Author(s):  
W.L. Wei ◽  
X.J. Zhao ◽  
Y.L. Liu ◽  
X.F. Yang
Keyword(s):  
Liquid Flow ◽  
Bubble Column ◽  
Numerical Study ◽  
Equations Of Motion ◽  
Transient Behavior ◽  
Bubble Columns ◽  
Two Phase ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Gas Liquid Flow

This paper is concerned with the numerical study of gas–liquid flow in bubble columns by large eddy simulations (LES). The Euler–Euler approach is used to describe the equations of motion of the two-phase flow. The mean velocities and the fluctuating velocities are obtained. It is found that, when the drag, lift and virtual mass forces are used, the computed results in agreement with experimental transient behavior can be captured.

Sign in / Sign up

Export Citation Format

Share Document