Sparger Design Research Articles

3D printed autoclavable biocompatible biodegradable bioreactor vessels with integrated sparger made from poly-lactic acid

3D printing has become widespread for the manufacture of parts in various industries and enabled radically new designs. This trend has not spread to bioprocess development yet, due to a lack of material suitable for the current workflow, including sterilization by autoclaving. This work demonstrates that commercially available heat temperature stable poly-lactic acid (PLA) can be used to easily manufacture novel bioreactor vessels with included features like harvest tubes and 3D printed spargers. Temperature responsiveness was tested for PLA, temperature stable PLA (PLA-HP) and glass for temperatures relevant for insect and mammalian cell culture, including temperature shifts within the process. Stability at 27 °C and 37 °C as well as temperature shifts to 22 °C and 32 °C showed acceptable performance with slightly higher temperature overshoot for 3D printed vessels. A stable temperature is reached after 2 h for PLA, 3 h for PLA-HP and 1 h for glass reactors. Temperature can be maintained with a fluctuation of 0.1 °C for all materials. A 3D printed sparger design directly integrated into the vessel wall and bottom was tested under three different conditions (0.3 SLPH and 27 °C, 3 SLPH and 37 °C and 13 SLPH and 37 °C). The 3D printed sparger showed a better kLa than the L-Sparger with more pronounced differences for higher flowrates. An insect cell culture run in the novel vessel exhibited the same growth behavior as that in standard glass vessels, reaching the same maximum cell concentration. Being 3D printed from biodegradable materials, these bioreactors offer design flexibility for novel bioreactor formats. Additionally, their autoclavability allows seamless integration into standard workflows.

Design parameters comparison of bubble column, airlift and stirred tank photobioreactors for microalgae production

Microalgae are the most propitious feedstock for biofuel production due to their lipid and fatty acid content. Microalgae cultivation shares many features with bioreactors, such as thermal and pH regulation, feeding procedures, and mixing to enhance heat and mass transfers. Aeration and stirring speeds are important parameters to reduce the costs of producing microalgae. In this study, three different photobioreactor types (stirred tank, airlift, bubble column) were characterized and compared for microalgae production. Hydrodynamics, mass transfer, and power consumption were determined for various aeration rates (0.9, 1.2, 1.5 L/min), and stirring speeds (100, 200 rpm), and Chlorella sorokiniana growth performance was compared under the conditions that provided the highest volumetric mass transfer and the lowest mixing time. Photo-bioreactor homogenization was good as indicated by low mixing times (< 10 s). Bubble column had the highest volumetric mass transfer due to its sparger design. Gas holdup and volumetric mass transfer coefficient were found to increase with the air flow rate and stirring speed. For stirred tank, bubble column, and airlift photobioreactors, maximum specific growth rates of C. sorokiniana were 0.053, 0.061, 0.057 h−1, and biomass productivities were 0.064, 0.097, 0.072 gdw/L.day, respectively. Under the conditions tested, growth was limited by the volumetric mass transfer in the airlift and stirred tank and bubble column was the best option for producing microalgae. These findings pave way for more extensive use of these systems in producing microalgae and provide a basis to compare photobioreactors of different designs.

Photobioreactors for utility-scale applications: effect of gas-liquid mass transfer coefficient and other critical parameters.

Cultivation of microalgae and controlling its growth and performance in closed photobioreactors (PBRs) are easier than open pond systems for wastewater treatment. The performance of PBRs is influenced by geometry, hydrodynamic behavior, and mass transfer. Horizontal and vertical configurations as common designs of PBR are reviewed based on their features, advantages, and disadvantages. However, vertically operated PBRs like bubble columns are preferably used for utility-scale applications of microalgae-based processes. Moreover, an appropriate reactor design reduces the inhibitory effect of dissolved oxygen concentration produced by microalgae and consequently increases the level of available CO2 in the medium. Medium properties, superficial gas velocity, gas holdup, bubble sizes, shear stress, mixing time, sparger design, and the ratio of inner diameter to effective height are shown to influence the overall volumetric mass transfer coefficient (KLa) and PBR's performance. The vertical PBRs like bubble columns provide a high mass transfer, a short liquid circulation time, and a long frequency of light/dark cycle for utility application of microalgae. Different flow regimes are obtained in PBRs based on the gas flow rate, inner diameter, and medium properties. Hydraulic retention time as the main operational parameter is determined in a batch mode for continuous wastewater treatment.

Interface mass transfer and properties of bubbly flows in a column with Newtonian and non-Newtonian liquids

The mass transfer of gas–liquid systems is commonly reported through the volumetric mass transfer coefficient, kLa, which is a function of several complex phenomena. To optimize the rate of mass transfer, increased knowledge about the individual effects of the interfacial area, a, and the liquid-side mass transfer coefficient, kL, on kLa is necessary. In this study, kLa was measured by monitoring the dissolved oxygen concentration in a bubble column. The bubble flows were recorded by a photographic method and the images were analyzed by means of artificial neural network to determine the bubble size. The effects of rheology, superficial gas velocity, and gas sparger design were analyzed. kL decreased with an increase in the superficial gas velocity and with an increase in the viscosity. The relative change in a was much larger compared to the relative change in kL, and hence, for the investigated operational conditions and liquid solutions, the change in kLa was mainly attributed to the change in a. Bubble clusters were formed in the non-Newtonian solutions but for the given operating conditions and liquid solutions, the bubble cluster formation did not have a prominent effect on the mass transfer.

Study of sparger design effects on the hydrodynamic and mass transfer characteristics of a D-shape hybrid airlift reactor

This study investigated the effect of sparger designs on a D-shape hybrid airlift reactor (DHALR) performances. The designs of airlift and torus reactors were combined to get the hybrid configuration. Experiments were carried out over a range of superficial gas velocities from 0.86 to 5.10 × 10−2 m/s, using three different spargers: single orifice (S-SO), multiple orifices (S-MO) and flexible membrane (S-FM). The findings highlighted that the S-FM sparger performed much better than the other spargers. An improvement in the gas holdup, εG, volumetric mass transfer coefficient, kLa, liquid circulation velocity, UL, and mixing time, tm, was observed and was attributed to the bubble size distribution enhancement. The S-FM sparger generates smaller and evenly distributed bubbles. However, it increases the axial dispersion coefficient and therefore the backmixing extent. It was demonstrated that even if S-FM leads to more pressure drop at the sparger level, it remains the most efficient in terms of power saving for a given mass transfer rate. The results demonstrated that the sparger has less effect at high superficial gas velocities in the DHALR. The flow inside the DHALR was modelled by the Axial Dispersion and the Tank in Series Models. The results show that the DHALR has a plug-flow-like behaviour.

H2 mass transfer – A key factor for efficient biological methanation: Comparison between pilot-scale experimental data, 1D and CFD models

Biological methanation is an emerging Power-to-Gas technology that provides a flexible, efficient, and long-term storage system to address the renewable energy intermittency issue. However, scaling-up a biological methanation plant requires overcoming the bottleneck of H2 gas–liquid mass transfer. The current work demonstrates analytically, experimentally and numerically the importance of H2 mass transfer on CH4 purity and productivity. The influence of sparger design was investigated in a pilot-scale bubble column bioreactor. An increase of 265 % in kLa and subsequently 81 % in CH4 purity is obtained when a uniform porous plate is used over a 4-points porous sparger. Numerical simulation of the bioreactor was performed using a multiscale modeling approach coupling 1D and CFD models. The numerical simulations were validated satisfactorily by the experimental data. Parametric studies were also performed using the 1D model to reveal the impact of operating conditions on the bioprocess. An analytical solution for the productivity of biomethanation reactors at steady-state is proposed based on mass balances and provides new insights into biological methanation. It is found that any modification of operating parameters that improve H2 mass transfer, such as higher gas recirculation rate and smaller bubble size, leads to a better bioreactor performance.

Analysis of bubble dynamics and thermal destratification induced by gas bubbles in cylindrical liquid storage tanks

• OpenFOAM code is modified to incorporate temperature-dependent transport properties. • A new parameter to estimate the extent of the destratification is introduced. • The destratification index increased by 25.29% as the diameter ratio is increased. • Bubble in square pitch with p/d =4 gives higher effectiveness for thermal destratification. • The destratification index increased by 44.65% as the gravity ratio is increased. Thermal stratification is of great concern for liquid propellant storage tanks of space vehicles. The present study's primary objective is to better understand the bubble dynamics on thermal destratification, quantify the extent of destratification and propose a scheme for destratification. This study investigates the effect of different geometric parameters on the destratification of thermally stratified layers of liquid using the volume of fluid and interface compression method of OpenFOAM CFD code. The OpenFOAM code is modified to incorporate temperature-dependent fluid properties. Different values of bubble diameter, spacing between the bubbles, and arrangement of bubbles in triangular and square fashion with different pitches are considered. The effect of gravitational forces on thermal destratification is also reported. For all these cases, the effectiveness of thermal destratification is quantified in terms of the destratification index ( I d ). The average destratification index ( I davg ) value increased by 25.29% as the ratio of bubble diameter to tank diameter ( d/D ) increased from 0.10 to 0.16. When the pitch to bubble diameter ratio ( p/d ) of triangular and square arrangements is reduced from 8 to 4, the I davg increases by 14.59% and 22.97%, respectively. The average destratification index increased by 44.65% when the g/g e ratio changed from 0.3 to 3. These studies give an overall idea of the sparger design for getting the correct gas flow rate for thermal destratification within the liquid propellant storage tanks.

Improving microalgae growth and carbon capture through micro-size bubbles generation in flat-panel photobioreactors: Impacts of different gas sparger designs on mixing performance

Anthropogenic emissions like carbon dioxide (CO2) necessitate the need for immediate mitigation of excessive CO2 concentrations, so as to ease the impacts of climate change. Mass carbon capture and storage (CCS) via microalgae cultivations have been proven prominent for their CO2 capturing abilities and prospects of converting CO2 into commercially valuable bioproducts. However, current microalgae cultivation systems have yet to achieve the satisfactory production rates required for mass CCS. To improve microalgae growth, CO2 gas bubbles are often fed to sustain microalgae cultures in photobioreactors (PBRs). Studies have shown significant increases in microalgae growth and CO2 capturing rates with the reduction of gas bubble sizes to micro-size. In this work, 3 distinct gas spargers were designed, and their mixing performances were investigated in a 10 L flat-panel PBR. Detailed analysis of micro-size bubbles generation via gas spargers, along with the cost analysis and carbon tax estimations for the sparger designs and operations, were discussed. The results of this work showed that spargers with micro-size pores were not able to produce micro-size bubbles. The customised sintered metal spargers with novel double sparger orientation resulted in higher mixing performances, compared to perforated spargers and commercial spargers. Findings advance the understanding of mixing and CO2 mass transfer, important milestones for photobioreactor scale-up studies and partly fulfil the circular bioeconomy concept where microalgae cultivations address both environmental and economic aspects.

Thermal destratification of cryogenic liquid storage tanks by continuous bubbling of gases

This paper focuses on thermal destratification and pressurisation inside thermally stratified storage tanks by continuous gas bubbling. The primary purpose of doing these studies is to better understand the effect of bubble dynamics on thermal destratification and quantify the extent of destratification. The volume of fluid and interface compression method of OpenFOAM CFD code is utilised for the present analysis. Different values of inlet gas velocities (Vg), orifice diameters (do), and arrangement of the orifices in triangular and square fashion with different pitches (p/do) are considered. In addition, the effect of gravitational forces (g/ge) on thermal destratification is also reported. For all these cases, the effectiveness of thermal destratification is quantified in terms of a newly defined parameter, the destratification index (Id). For Vg = 1 m/s, the Id value is maximum compared to lower Vg values. It is seen that when the gas velocity increased from 0.3 m/s to 1.0 m/s, the average effectiveness in thermal destratification (Idavg) and pressure at the ullage increased by 44.38% and by 64.81%, respectively. The Idavg and pressure at ullage increased by 96.29% and 14.91%, respectively, when the g/ge ratio changed from 0.3 to 3. Compared to the triangular arrangement with p/do = 10, the calculated Idavg increased by 30.67% when gas inlets were arranged with a square pitch of 10. For p/do = 4, 6 and 8, the increments in Idavg are of the order of 12.86%, 19.43% and 21.92%, respectively, for gas inlets arranged in a square fashion as compared to the triangular arrangement. It is found that continuous bubbling with gas inlets arranged in square pitch p/do = 10 gives higher effectiveness in thermal destratification. Thus, by these studies, one can develop a thermal destratification mechanism with continuous bubbling for optimum performance. Also, these studies give an overall idea of sparger design for getting the correct gas flow rate for thermal destratification within the cryogenic liquid storage tanks.

Predictive analysis of gas hold-up in bubble column using machine learning methods

In designing a gas-liquid bubble column, an accurate estimation of the gas hold-up is important. A generalized Machine learning-based data-driven methodology is presented to predict the gas hold-up, with the industrial-scale application for designing a bubble column. The predictions by machine learning methods such as support vector regression (SVR), random forest (RF), extra trees (EXT), and artificial neural network (ANN) have been compared. The methodology adopted for the prediction of gas hold-up with the help of independent parameters such as column diameter, column height, sparger design, sparger location, percentage free area, superficial gas, liquid velocity, pressure, temperature, the density of gas & liquid, viscosity of gas & liquid, surface tension has been presented. An extensive set of experimental data (4042 data points) has been extracted from the literature covering various design and operating parameters. The performance of the machine learning methods has been compared using mean absolute percentage error (MAPE), mean square error (MSE), and determination coefficient/prediction accuracy (R-square). Based on these statistical parameters, with 97% of prediction accuracy (R-square), MSE = 0.00031, and MAPE = 7.9, the performance of the extra tree is found to be most suitable for the prediction of the gas hold-up.

Characterisation of a simple ‘hanging bag’ photobioreactor for low‐cost cultivation of microalgae

AbstractBACKGROUNDMicroalgae are a diverse group of photosynthetic microorganisms of significant interest to the biotechnology industry, either as a sustainable source of natural compounds, or as light‐driven cell factories to produce recombinant metabolites and proteins. Their ability to utilise light, CO2, and basic nutrients leads to a simple and low‐cost phototrophic cultivation process. This is particularly relevant to low‐ and middle‐income countries, all of which require a cultivation system that is cheap, technically simple to operate, readily scalable, and can meet basic Good Manufacturing Practice requirements. A disposable ‘hanging bag’‐type photobioreactor operated as a bubble column fits these criteria.RESULTSIn this study, the characterisation and design modifications to improve the performance of a 15 L hanging bag is reported. The bubble behaviour using different sparger designs was investigated together with gas hold‐up, mixing time, and mass transfer coefficient of CO2. A gas flow rate of 5 L min−1 using a new sparger design and a modified height‐to‐diameter ratio of the bag led to a two‐fold improvement in algal biomass productivity when culturing the green microalga Chlorella sorokiniana. The cultivation of a luciferase‐expressing Chlamydomonas reinhardtii strain in the modified hanging bag also demonstrated an 11% increase in luciferase content.CONCLUSIONThis is the first attempt to characterise this simple hanging bag system that brings the industry‐favoured single‐use bag concept into the research field of photobioreactor technology. The hanging bag with modified sparger and dimensions improves microalgal biomass productivity and demonstrates the potential of simple and low‐cost systems for microalgal cultivation. © 2021 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley &amp; Sons Ltd on behalf of Society of Chemical Industry (SCI).

Effects of sparger design on the gas holdup and mass transfer in a pilot scale external loop airlift reactor

Three designs of static spargers were used in a pilot scale external loop airlift reactor to determine their effects on the gas holdup and mass transfer characteristics for an air-water system. Although previous studies involving the effects of sparger design on gas holdup and mass transfer have been reported, no comparative investigations using different spargers in the same pilot scale external loop airlift reactor have been done. In this investigation, the results show that the perforated plate sparger (A) was the best design and produced the best overall gas holdup and mass transfer values when compared to a perforated disk sparger (B) and perforated pipe sparger (C). The perforated pipe sparger produced the worst gas holdup and mass transfer values and also had the worst overall performance for bubble size, flow and distribution. This investigation emphasises the importance of sparger design and that it must be considered in the overall design of an airlift reactor as it has a significant influence on the gas holdup and mass transfer characteristics.

The effect of operating and design parameter on bubble column performance: The LOPROX case study

It is known that the performances of multi-phase reactors depend on the operating parameters (the temperature and the pressure of the system), the phase properties, and the design parameters (the aspect ratio (AR), the bubble column diameter, and the gas sparger design). Hence, the precise design and the correct operation of multi-phase reactors depends on the understanding and prediction of the fluid dynamics parameters. This paper contributes to the existing discussion on the effect of operating and design parameter on multi-phase reactors and, in particular, it considers an industrial process (e.g., the LOPROX (low pressure oxidation) case study, which is typical example of two-phase bubble columns). Based on a previously-validated set of correlations, the influence of operating and design parameter on system performances is studied and critically analyzed. First, we studied the effects of the design parameter on the liquid–gas interfacial area, by keeping constant the fluid physical–chemical properties as well as the operating conditions; subsequently, we discussed for a fixed system design, the influence of the liquid phase properties and the operating pressure. In conclusion, this paper is intended to provide guidelines for the design and scale-up of multi-phase reactors.

Auto-Aspirated DAF Sparger Study on Flow Hydrodynamics, Bubble Generation and Aeration Efficiency

A novel auto-aspirated sparger is examined experimentally in a closed-loop reactor (CLR) at lab scale using particle image velocimetry, high-speed camera and oxygen mass transfer rate measurements. State-of-the-art 3D printing technology was utilized to develop the sparger design in stainless steel. An insignificant change in the bubble size distribution was observed along the aerated flow, proving the existence of a low coalescence rate in the constraint domain of the CLR pipeline. The studied sparger created macrobubbles evenly dispersed in space. In pure water, the produced bubble size distribution from 190 to 2500 μm is controlled by liquid flow rate. The bubble size dynamics exhibited a power-law function of water flow rate approaching a stable minimum bubble size, which was attributed to the ratio of the fast-growing energy of the bubble surface tension over the kinetic energy of the stream. Potentially, the stream energy can efficiently disperse higher gas flow rates. The oxygen transfer rate was rapid and depended on the water flow rate. The aeration efficiency below 0.4 kW/m3 was superior to the commonly used aerating apparatuses tested at lab scale. The efficient gas dissolution technology has potential in water treatment and carbon capture processes applications.

Fluid dynamic conditions and oxygen availability effects on microbial cultures in STBR: An overview

Bioprocesses are often carried out in stirred tank bioreactors. Due to the need of mixing, homogenization and interphase transports, cultures are usually agitated by mechanical, hydraulic or pneumatic means. The increasing in agitation decreases mixing time, improves homogeneity, mass and heat transfer rates and, accordingly, the metabolism and the biochemical reaction rates are also influenced. The power input into the system is essentially required in order to increase the mass transfer rate, the oxygen transport rate in aerobic bioprocesses, but also the shear forces are increased and consequently the concentration of some compounds in the liquid phase (oxygen in the aerobic bioprocess) with the corresponding effects on the cellular metabolism and the cellular structures due to fluid dynamics into the bioreactor. Hydrodynamic conditions in STBR are given by the broth characteristic (mainly viscosity), the vessel geometry, including the stirrer and sparger design, and the agitation and gas flow rate. Thus, shear effects would take place, affecting the culture performance, provoking cell damage in some occasions. The primary goal of this work is to describe up to date knowledge on these concepts: fluid dynamic conditions, hydrodynamic stress and oxygen availability influence affecting the microbial processes performance.

Predicting Mass Transfer in Pilot Scale External Loop Airlift Reactors using Neural Networks

An artificial neural network (ANN) was built using selected input data of Newtonian fluids in pilot scale external loop airlift reactors of varying designs, in order to predict the mass transfer coefficient in other external loop airlift reactors with more general geometry. 663 data points were generated using air-glycerine and air-water systems in 5 different configurations of pilot scale external loop airlift reactors with 3 categories of sparger design. The data was modelled using the artificial neural network software, Predict (Version 3.30) by Neuralware. The correlation coefficient (R) for the neural network model was 0.98. The model was tested with unseen external data from various sources of which the R values ranged from 0.91 to 0.99. Additional external data, out of the experimental range of this investigation was evaluated, for which the R values ranged from 0.67 to 0.85. The ANN gave excellent approximations for the data within or below the training parameters.

Eulerian-Eulerian Approach to CFD Simulation of Two-Phase Bubble Column

Calculation work is carried out in the present project to study the effect of different parameters on hydrodynamics of gas-liquid flow by using CFD. The steady state and transient, three dimensional simulations are performed of the whole bubble column for various inlet gas and sparger designs. A standard k-ε is used to describe turbulence occurring in the continuous fluid. Results show he asymmetric recirculation stronger with an increase in the number of holes giving better mixing. The gas hold-up increased with superficial gas velocity but independent of the sparger design at high velocity. Comparison of simulation results with the previous experimental work data has provided a successful validation of the model.

Understanding the effect of high gas entrance velocity on Chinese hamster ovary (CHO) cell culture performance and its implications on bioreactor scale-up and sparger design.

There are three main potential sources for cell shear damage existing in stirred tank bioreactors. One is the potential high energy dissipation in the immediate impeller zones; another from small gas bubble burst; and third is from high gas entrance velocity (GEV) emitting from the sparger. While the first two have been thoroughly addressed for the scale-up of Chinese hamster ovary (CHO) cell culture knowing that a wide tolerable agitation range with non-damaging energy dissipation exists and the use of shear protectants like Pluronic F68 guard against cell damage caused by bubble burst, GEV remains a potential scale-up problem across scales for the drilled hole or open pipe sparger designs. GEV as high as 170 m/s due to high gas flow rates and relatively small sparger hole diameters was observed to be significantly detrimental to cell culture performance in a 12,000 L bioreactor when compared to a satellite 2 L bioreactor run with GEV of <1 m/s. Small scale study of GEV as high as 265 m/s confirmed this. Based on the results of this study, a critical GEV of >60 m/s for CHO cells is proposed, whereas previously 30 m/s has been reported for NS0 cells by Zhu, Cuenca, Zhou, and Varma (2008. Biotechnol. Bioeng., 101, 751-760). Implementation of new large scale spargers with larger diameter and more holes lowered GEV and helped improve the cell culture performance, closing the scale-up gap. Design of such new spargers was even more critical when hole plugging was discovered during large scale cultivation hence exacerbating the GEV impact. Furthermore, development of a scale down model based on mimicry of the large scale GEV profile as a function of time was proven to be beneficial for reproducing large scale results.

Sparger design as key parameter to define shear conditions in pneumatic bioreactors

The average shear rate (γ˙av) is a parameter used to characterize the shear environment in bioreactors, enabling comparison of the performances of different bioreactor models in terms of microorganism morphology and viability, and consequently bioproduct formation. Based on this approach, pneumatic bioreactors have been classified as low shear devices. However, the shear behavior cannot be generalized over a wide range of operating conditions, suggesting that the maximum shear rate (γ˙max) may be more suitable for the purpose of bioreactor performance comparison. Therefore, the aim of this work was to evaluate average and maximum shear rates in pneumatic bioreactors (bubble column and airlift), based on computational fluid dynamics (CFD) simulations. Concentric-duct and split airlift bioreactors exhibited higher γ˙av values, compared to the bubble column design, due to the nature of the liquid circulation patterns. The pneumatic bioreactors exhibited a significant (order of magnitude) difference between γ˙av (11.0–27.3 s−1) and γ˙max 4555 to 25,040 s−1), reflecting a non-uniform spatial distribution. The γ˙max values occurred close to the sparger holes and presented a linear relationship with gas injection velocity, which is dependent on the sparger geometry. In this way, sparger characteristics (number and diameter of sparger holes) defined γ˙max values in pneumatic bioreactors, showing that sparger should be properly designed in order to avoid excessive local shear rates.

Effects of Chemical Reactions on the Local Hydrodynamics in Slurry Bubble Column Reactors Operating under Typical Fischer-Tropsch Process Conditions – Ii

AbstractOur rigorously validated Computational Fluid Dynamics (CFD) model (Basha et al. 2016) was previously used to predict the effects of gas sparger designs and internals configurations on the local hydrodynamics in a pilot-scale and a conceptual large-scale slurry bubble column reactors (SBCRs) (Basha and Morsi 2018). In this study, the CFD model was used to predict the effect of incorporating the F-T reaction kinetics on the local hydrodynamics in the pilot-scale (0.3-m ID, 3-m height) and the overall performance of the pilot-scale and an industrial-scale (5.8-m ID, 42-m height) SBCRS, both operating under F-T conditions with iron catalyst.In the pilot-scale SBCR, the CFD simulations were carried out with catalyst concentrations of 5, 10 and 15 vol% and three H2/Co ratios of 1, 1.5 and 2, at temperature of 443 K, pressure of 20.5 bar and a superficial gas velocity of 0.24 m/s. The predictions showed that the presence of chemical reactions decreased the gas holdup and the Sauter mean bubble diameters along the reactor height by an average of 15.4 % and 17.63 %, respectively and strengthened the liquid circulations near the reactor wall. The predictions also showed that the CO and H2conversions increased with increasing the catalyst concentration, and the pilot scale SBCR could produce a maximum of 1.87 tons/day of C5+products at a catalyst concentration of 15 vol%.In the commercial-scale SBCR, the CFD simulations were conducted at a catalyst loading of 10 vol% at a temperature of 528 K, pressure of 29 bar and four superficial gas velocities of 0.12, 0.24, 0.3 and 0.4 m/s. The calculations were completed, however, the contours of the local hydrodynamics were not extracted due to computational and memory limitations associated with generating graphics of such a large and complex reactor geometry. The predictions showed that the CO conversions were 48 %, 59 %, 58 % and 55 %; the H2conversions were 36 %, 51 %, 56 % and 54 % and the C5+products yields were are 275, 576, 627 and 654 ton/day at the superficial gas velocities of 0.12, 0.24, 0.3 and 0.4 m/s, respectively. When comparing the CFD model predictions with those of the 1-D empirical model developed by Sehabiague et al. (Sehabiague et al. 2015) at a superficial gas velocity of 0.24 m/s and catalyst loading of 10 %, the CFD model was found to predict lower CO conversion, higher H2conversion and higher C5+yield.