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

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

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

2015 ◽  
Vol 13 (3) ◽  
pp. 201-288 ◽  
Author(s):  
Omar M. Basha ◽  
Laurent Sehabiague ◽  
Ahmed Abdel-Wahab ◽  
Badie I. Morsi
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Bubble Column ◽  
Cfd Modeling ◽  
Transport Parameters ◽  
Empirical Correlations ◽  
Transfer Coefficients ◽  
Operating Variables ◽  
Bubble Column Reactors ◽  
Computational Fluid Dynamics Cfd

Abstract 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.

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%.

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