Vertical Internals Research Articles

Simulation Study on Hydrodynamic Performance of Slurry Bubble Column with Vertical Tube Internals

The gas-liquid-solid mixing characteristics in slurry bubble column were studied using the CFD-PBM model under different cross section coverage ratios of tubes. The research shows that with the increase of the proportion of the cross section area of the vertical tube, the flow field in the slurry bubble column tends to be stable, the liquid phase flow rate in the column becomes faster, and the large-scale liquid circulation strengthens, resulting in the decrease of gas holdup. As the proportion of cross section area in the vertical column increases, the distribution of gas-solid holdup becomes more uneven in the radial direction. However, increasing the number of vertical tubes can improve the axial distribution of solid particles in the reactor while reducing the size of bubbles in the column. Therefore, it can be concluded that in order to achieve effective gas, liquid, and solid mixing in slurry bubble column, the ratio of cross section area of vertical internals is crucial under given conditions.

Partitioning of a wide bubbling fluidized bed with vertical internals to improve local mixing and bed material circulation

Industrial scale fluidized bed reactors are characterized by limited mixing rates, either local or global, especially when using low-pressure drop gas distributors to reduce operational costs. In this work, partitioning of wide beds using vertical internals is proposed as an effective technique to improve local mixing in large reactors, i.e., mixing in specific zones of the bed. The effect of the vertical internals height on local solids mixing within partitions was experimentally evaluated in a pseudo-2D bed by analyzing the velocity and flow structure of the solids and the circulation time within individual partitions. In the presence of internals, global mixing, i.e., mixing between neighboring partitions and across the entire reactor, may be reduced as vertical internals compartmentalize the bed. Thus, the effect of the internals height on global mixing was also quantified while using bed materials with the same properties, but differing in color, in the different partitions, and analyzing the time evolution of the concentration of solids. Furthermore, the effect of internals on bubbles was also evaluated for different internal heights. It was found that internals with a height between the gulf-stream height and the fixed bed height promote the appearance of vortex pair structures in each partition of the wide bed. These structures substantially improve local mixing within each partition, while global mixing between partitions is practically unaffected by the presence of these short internals. • Pseudo-2D bed was used to characterize the effect of vertical partitions on mixing. • Solids with different colors were used to evaluate local and global mixing. • A model is developed to determine the exchange efficiency between partitions. • Vortex pair structures appear with internals above the gulf-stream height. • Vortex structures improve local mixing, global mixing remaining nearly unaffected.

Impact of vertical internals on the hydrodynamics and separation performance of a gas–solid separation fluidized bed

Gas–solid separation fluidized beds are one of the main equipment for the clean utilization of coal resources in China. The vertical internals has a strong influence on the fluidized beds. The combination of Fluent simulation and experimental measurements was used to study the performance of a fluidized bed. The results show that vertical internals can inhibit the formation of larger bubbles evidently at high gas velocity, and divide the original particle circulation flow field into several small cycles, which plays a positive role in promoting the particle mixing, thus, improving the fluidization quality. A fluidized bed with five vertical internals was used to separate 6–50 mm raw coal. The ash content of clean coal is 16.03% with a yield of 43.29%, while the ash content of gangue is 43.60% with a yield of 56.71%. Probable error, E, value is as low as 0.13 g/cm3, which indicates good separation performance.

CFD investigation of the gas dispersion and liquid mixing in bubble columns with dense vertical internals

Bubble columns are widely equipped with vertical internals for heat removal in slurry/bubble column reactors or providing the light source in photobioreactors. Understanding the effect of internals on the hydrodynamics of a bubble column reactor is crucial for the reactor design and scale-up. The gas dispersion and liquid mixing are two important parameters in design of bubble columns. In this study, the Eulerian-Eulerian simulation coupled with the population balance model was developed for the bubble column with dense vertical internals. The impulse tracer injection was applied to study the gas dispersion. The effect of the gas flow fluctuations, the time span of tracer injection, and the presence of internals was assessed at different superficial gas velocities. The results showed that the presence of internals has a notable effect on gas behavior. A stronger gas velocity gradient with less turbulence and dispersion were observed in the presence of internals. To study the liquid mixing, the tracer technique was applied, and the sensitivity of results to the tracer injection and detector points have been discussed. The presence of internals reduced the fluctuating liquid velocities, which led to a lower mixing performance in the bubble column.

Hydrodynamic investigations by a local optical measurement technique designed for high-temperature applications – first measurements at a fluidized bed immersed by vertical internals at cold conditions

The hydrodynamic properties significantly influence the performance of bubbling fluidized bed reactors. For this reason, it is necessary to conduct hydrodynamic measurements for which several different measurement techniques are available. However, many of them are limited by their range of application concerning the temperature and the reactive conditions. In the course of this study, an optical measurement technique was applied to investigate a bubbling fluidized bed. The optical measurement technique is designed in a way to withstand temperatures of up to 400 °C under reactive conditions. However, all experiments were conducted at ambient temperature since one general objective of the present study was to demonstrate the applicability of the sensor for hydrodynamic measurements. A new algorithm was developed to extract the bubble events out of the signal that is generated by the optical sensor. In the scope of the measurement campaign, the fluidization number, the absolute pressure and both the vertical and radial measurement positions were varied. Some trends on the influence of these parameters on the bubble properties like the pierced chord length, the bubble rise velocity or the hold-up could be identified and explained.

Influence of heat-exchanging tubes diameter on the gas holdup and bubble dynamics in a bubble column

The effects of the presence of vertical internal tubes and their diameters on the local gas holdup and bubble dynamics, including the specific interfacial area, bubble chord length, and bubble velocity were investigated in a 6 in. bubble column for the air-water system by using a four-point optical fiber probe technique. Two different diameters, 0.5-inch, and 1-inch, of vertical internals equally covering 25% of the column's cross-sectional area (CSA) were used to represent the heat-exchanging tubes utilized in the Fischer Tropsch (FT) process. For both sizes, the vertical internals were uniformly distributed over column CSA. The experiments were performed using the air-water system, in a 6-inch bubble column at superficial gas velocities of 20, 30, and 45 cm/s. The experimental results indicated that the presence of vertical internals and their diameters have a significant effect on the hydrodynamic properties of the bubble column reactor at high superficial gas velocities. The local gas holdup significantly increased in the core region and decreased at the wall regions when the 0.5-inch vertical internals were used. Contrarily, the 1-inch vertical internals enhanced the gas holdup near to the wall regions. Additionally, the bubble chord length and the bubble rise velocity were found to be larger in the presence of vertical internals, especially at high superficial gas velocities. The specific interfacial area with the 0.5-inch internal was much lower than bubble column without vertical internals, but while using 1-inch internals, it was enhanced in the wall regions.

A comprehensive CFD study on the effect of dense vertical internals on the hydrodynamics and population balance model in bubble columns

In this paper, the effects of dense vertical internals (rods) on gas holdup and local gas and liquid velocities were investigated by using the Eulerian-Eulerian model coupled with the population balance model. The inclusion of lift and wall lubrication forces was studied by applying different models. The results indicated that just by choosing the appropriate interfacial forces, the numerical model agrees well with the experimental data. A sharper gas holdup, a stronger gas velocity gradient, and a more intense liquid recirculation were observed as the important impacts of the internals. Moreover, three circular internals’ arrangements were considered to study the effect of wall and core clearance distances on the bubble column hydrodynamics. The results revealed that by increasing the wall clearance distance, flatter gas holdup and velocity distributions could be achieved. Also, the turbulence parameters were used to evaluate the capability of the model in the prediction of the bubble size distribution. A modification factor for the breakage and coalescence kernels was proposed; the factor enabled the model to reach equilibrium mean diameters for bubbles. The comparison of the probability distribution function (PDF) of bubble sizes in the bubble column with and without internals showed a narrower bubble size distribution with a smaller mean diameter in the presence of internals.

Effect of vertical internals on the pressure drop in a gas‐solid fluidized bed

AbstractIn this work, the pressure drop at the wall and the radial profiles of pressure drop along the bed height have been measured using a differential pressure transducer and pressure probe‐differential pressure transducer in a gas‐solid fluidized bed with a 0.14 m inside diameter. Two types of circular arrangements of intense vertical internals (0.0254 and 0.0127 m diameter), two kinds of solid particles of Geldart B type (glass beads and aluminum oxide), and four selected superficial gas velocities in terms of u/umf have been used to study the impact of these different designs, as well as the physical and operating variables on the pressure drop measured at the wall of the bed and the radial pressure drop inside the fluidized bed. It has been experimentally demonstrated that the 0.0254 m internals can reduce the pressure drop at the wall and the radial pressure drop inside the bed by about 10 % when compared to without internals, and this result holds true for both kinds of solids used. However, the implementation of 0.0127 m internals inside the gas‐solid fluidized bed leads to a decrease in the pressure drop and radial pressure drop in the case of glass bead solid particles and an increase in the pressure drop in the case of aluminum oxide solid particles. The experimental results in the form of relevant dimensionless groups have been correlated using the statistical analysis software of JMP 12, due to the big difference between the experimental results of this work and the predicted values from the available correlations in the literature. The new correlation has been developed with a mean relative deviation value of 1.08 % between the experimental and predicted values.

Flow regimes in gas–solid fluidized bed with vertical internals

In this work, the impact of the vertical internals on the flow regimes and their transition velocities has been studied in a 0.14m inside diameter gas–solid fluidized bed. The identification of the flow regimes was accomplished statistically (standard deviation) and chaotically (Kolmogorov entropy) by analyzing the pressure drop fluctuations. Circular configurations of vertical tubes with two different sizes (0.0254 and 0.0127m diameter), two kinds of solid particles of Geldart B type (glass beads and aluminum oxide), and a wide range of superficial gas velocities (0.15–1.2m/s) have been implemented in this study. Generally, it was demonstrated that the vertical internals have a significant effect on the flow regimes, transition velocities, and transition velocity ranges of each individual flow regime.However, such effect is a function of the physical properties of the used solid particles in which the turbulent transition velocity (Uc) decreased in the case of glass beads and increased in the case of aluminum oxide for both of the configuration designs of vertical internals used in the present work. In addition, the 0.0254m vertical internals type has been shown to be more efficient either in minimizing the turbulent transition velocity (Uc) and superficial gas velocity within the range of slugging flow regime and increasing the range of the superficial gas velocity within the range of bubbling flow regime or in reducing the pressure drop and pressure fluctuations inside the bed.

The impact of vertical internals array on the key hydrodynamic parameters in a gas-solid fluidized bed using an advance optical fiber probe

The effect of a circular configuration of intense vertical immersed tubes on the hydrodynamic parameters has been investigated in a gas-solid fluidized bed of 0.14 m inside diameter. The experiments were performed using glass beads solid particles of 365 μm average particle size, with a solid density of 2500 kg/m3 (Geldart B). An advanced optical fiber probe technique was used to study the behavior of six essential local hydrodynamic parameters (i.e., local solids holdup, particles velocity, bubble rise velocity, bubble frequency, and bubble mean chord length) in the presence of vertical immersed tubes. The experimental measurements were carried out at six radial positions and three axial heights, which represent the three key zones of the bed: near the distributor plate, the middle of the fluidizing bed, and near the freeboard of the column. Furthermore, four superficial gas velocities (u/umf = 1.6, 1.76, 1.96, and 2.14) were employed to study the effect of operating conditions. The experimental results demonstrated that the vertical internals had a significant effect on all the studied local hydrodynamic characteristics such that when using internals, both the solids holdup and bubble mean chord length decreased, while the particles velocity, bubble rise velocity, and bubble frequency increased. The measured values of averaged bubble rise velocities and averaged bubble chord lengths at different axial heights and superficial gas velocities have been compared with most used correlations available in the literature. It was found that the measured values are in good agreement with values calculated using predicted correlation for the case without vertical internals. While, the absolute percentage relative error between the measured and calculated values of these two hydrodynamic parameters indicate large differences for the case of vertical internals.

Investigating the influence of the configuration of the bundle of heat exchanging tubes and column size on the gas holdup distributions in bubble columns via gamma-ray computed tomography

The impact of dense vertical internal tubes and their configurations on the gas holdup distributions and their diametrical profiles in pilot-scale bubble column is visualized and quantified for the first time ever using an advanced gamma-ray computed tomography (CT) technique. Two arrangements of vertical internals (circular and hexagonal configurations) occupying the same cross-sectional area (CSA) of the column (about 25% of the total cross-sectional area to represent the heat exchanging tubes that are used in the Fischer-Tropsch synthesis), were examined in addition to the measurement in the bubble column without vertical internals. Moreover, the gas holdup distribution results of the 18-inch (0.46 m in outer diameter, O.D.) bubble column are compared with an available data of 6-inch (0.15 m in O.D.) bubble columns with and without vertical internals. CT scans have been conducted for 18-inch bubble columns with and without vertical internals for the air-water system under a wide range of superficial gas velocity (0.05–0.45 m/s). The experimental results indicate that an improvement in the gas holdup distribution over the column's cross-sectional area is obtained when the vertical internal tubes (arranged in either a circular or a hexagonal configuration) were used. However, better cross-sectional gas holdup distribution was achieved in the bubble column with vertical internals arranged in a hexagonal configuration as compared to the bubble column without and with vertical internals arranged in a circular arrangement. Additionally, the averages of the cross-sectional gas holdup and their profiles for bubble column with and without vertical internals are close to each other when the bubble column with vertical internals is operating at a high superficial gas velocity, which is calculated based on the free cross-sectional area for the flow. Furthermore, the gas holdup distributions are further improved when the larger bubble column with vertical internals was used as compared to the 6-inch bubble columns with and without vertical internals.

Impact of heat-exchanging tube configurations on the gas holdup distribution in bubble columns using gamma-ray computed tomography

An advanced gamma-ray computed tomography (CT) technique was used for the first time to visualize and quantify the impacts of the presence of heat-exchanging tubes and their configurations on the gas-liquid distributions and their profiles in a 6-inch (0.1524 m O.D.) Plexiglas® bubble column in an air-water reactor. Two superficial gas velocities (i.e., 0.2 and 0.45 m/s) were employed to simulate the churn turbulent flow regime. To investigate the impact of vertical internals configurations, three arrangements (i.e., hexagonal, circular without a central internal, and circular with a central internal) were employed in addition to the column with no internals. Using the same sized vertical internals and the same occluded cross-sectional area (CSA), it was found that the configuration of the vertical internals significantly impacted the gas holdup distribution over the CSA of the column. All studied superficial gas velocities resulted in symmetrical gas holdup distributions over the CSA of the bubble columns without vertical internals; however, the columns equipped densely with vertical internals did not have symmetrical gas holdup distributions. The presence of an extra central tube in the circular configuration played a key role in the gas-liquid distribution over the CSA of the bubble column. The hexagonal configuration had the advantage of providing the best spread of the gas phase over the entire CSA of the column. Gas holdup values at the wall region of the bubble column increased with the addition of vertical tubes in all investigated configurations. However, a remarkable increase in the gas holdup values was obtained with the hexagonal configuration. The experimental data (i.e., gas holdup distributions and their diametrical profiles) can help to evaluate and validate three-dimensional (3-D) computational fluid dynamics (CFD) simulations to better predict the hydrodynamic parameters involved in these types of reactors.

Advanced analysis of liquid dispersion and gas–liquid mass transfer in a bubble column with dense vertical internals

The influence of dense vertical tube bundles in a batch bubble column reactor (BCR) of 100mm diameter and 1100mm clear liquid height on liquid dispersion and gas–liquid mass transfer was studied. In particular, the effects of different tube patterns (triangular and square pitch), tube diameters (8 and 13mm) and bottom end designs (flat and U-tube) having a tube diameter-to-pitch ratio of approx. 1.3 were investigated.Dispersion coefficients were determined based on conductive tracer experiments recorded via wire-mesh sensors (WMS) with up to 90 measurement points distributed in the column’s cross-section in between the tubes. The gas–liquid mass transfer coefficient was determined via fast-responding oxygen needle probes. Tube pitch and pattern were identified as the most crucial design parameters for the extent of liquid dispersion. We found that particularly the U-tube bottom end design induces large liquid circulation patterns, which enhance dispersion. The presence of internals decreases the kla value as a consequence of turbulence damping, which is also confirmed by lower kl values (e.g. 0.6×10−3ms−1 for the empty BCR and 0.25×10−3ms−1 for the square pitch with 8mm tubes at 0.05ms−1 superficial gas velocity), whereas the pitch is the most decisive design parameter. The U-tube bottom end design was identified as the most beneficial configuration with respect to liquid mixing and gas–liquid mass transfer.

Influence of the size of heat exchanging internals on the gas holdup distribution in a bubble column using gamma-ray computed tomography

The effects of the presence of the vertical internals of different sizes at a wide range of superficial gas velocity on the overall, local gas holdup distributions and their profiles have been studied and quantified in a 6-in. (0.14 m) Plexiglas® bubble column with air-water system using a non-invasive advanced gamma-ray computed tomography (CT) technique. In this study, two sizes of Plexiglas® vertical internals, having the same occupying area (∼25%) of the column's cross-sectional area (CSA) that represents those used in Fischer-Tropsch synthesis, have been used within a range of superficial gas velocities that cover bubbly and churn turbulent flow regimes (0.05–0.45 m/s). The reconstructed CT scan images revealed that the bubble columns equipped with or without internals displayed a uniform cross-sectional gas holdup distribution (symmetric) for all studied superficial gas velocities. However, the bubble column equipped with 1-in. vertical internals exhibited more uniform gas holdup distribution than the column with 0.5-in. internals. Also, the visualization of the gas-liquid distributions for bubble columns with and without internals reveal that the well-known phenomenon of the core-annular liquid circulation pattern that observed in the bubble column without internals still exists in bubble column packed densely with vertical internals. Moreover, a remarkable increase in the gas holdup values at the wall region was achieved in the churn turbulent flow regime based on the insertion of the vertical internals inside the column as compared with using a bubble column without obstacles. Furthermore, the values of the gas holdup in the core region of the bubble column with vertical internals are similar to those of the bubble column without vertical internals when they are operated at high superficial gas velocity (churn turbulent flow regime), based on the free cross-sectional area (CSA) for the flow. In general, the magnitude of the gas holdup increased significantly with increasing superficial gas velocity for the bubble columns with and without internals. However, the gas holdup profile was shaped like a wavy line in the bubble column with vertical internals, whereas it exhibited a parabolic gas holdup profile in the bubble column without obstacles.

Generation and evaluation of an artificial optical signal based on X-ray measurements for bubble characterization in fluidized beds with vertical internals

The performance of fluidized bed reactors strongly depends on the bubble behavior, for which reason knowledge concerning the bubble properties is important for modeling and reactor optimization. X-ray measurements can be used to characterize bubbles within the cross-section of a fluidized bed on a laboratory scale, but cannot easily be extended to hot, pressurized large scale plants. For future measurements at hot conditions in a fluidized bed methanation reactor, we have developed an optical probing system that can be employed under these conditions. However, optical sensors are only able to investigate the local fluidization patterns at a defined position in the bed. The objective of this study is to characterize differences in bubble properties between local optical measurements and an X-ray tomography method that is able to detect bubbles over the entire cross-section. Therefore, an artificial optical signal is created out of existing hydrodynamic X-ray measurement data obtained at a cold flow model of a pilot scale methanation reactor. The determined bubble properties of both methods (i.e. evaluation of the derived artificial optical probe signal and image reconstruction based on the evaluation of original X-ray tomographic data) are compared with regard to the bubble rise velocity and the bubble size (for the X-ray method) or pierced chord length (for the optical evaluation method), respectively. The comparison shows that for the evaluation of the optical probe data, statistical effects have to be considered carefully. The detected mean chord length of the optical method does not immediately correspond to the mean bubble size determined by the X-ray method. Moreover, also differences regarding the bubble rise velocity were detected for some fluidization states. The reason for the discrepancies between both methods could be identified and corrected, amongst others by means of a Monte Carlo simulation in which rising bubbles in a fluidized bed were simulated and characterized by a local virtual optical sensor.

Simulating the impacts of internals on gas–liquid hydrodynamics of bubble column

Impacts of vertical internals on gas–liquid hydrodynamic of bubble columns were simulated using an Eulerian two fluid model coupled with a population balance method (TFM-PBM). The interfacial drag force, the shear induced lift force, and the radial wall lubrication force exerted on bubbles were included in the model. The effects of wall boundary conditions were investigated numerically. The numerical results showed the radial wall lubrication force greatly impacts the radial distribution of time-averaged gas holdup, especially in the internals affecting region. When the internals were present, the turbulent dissipation rates increased significantly in the gaps between the internal walls, and more bubbles with smaller bubble size were predicted in the bubble column. Meanwhile, the gas holdup increased with dense internals insertion, especially in r/R equal to 0.6–0.9 region. The internals and the configurations influence the overall liquid circulation. When 31 thin internals are inserted in column at a low superficial gas velocity, large scale liquid circulations are replaced by small local vortex. However, the variations of liquid circulations are different at a high superficial gas velocity, when the large scale liquid circulations are always present in the column regardless of inserting 31 thin internals or 8 thick internals.

Influence of vertical heat exchanger tubes, their arrangement and the column diameter on the hydrodynamics in a gas–solid bubbling fluidized bed

The hydrodynamic behavior of a cold-flow gas–solid fluidized bed with an inner diameter of 22 cm is investigated by means of an ultra-fast X-ray tomographic setup. In the case of an exothermal reaction, heat exchanger tubes are required to remove the reaction heat out of the bubbling fluidized bed reactor. For the examined cold-flow model, the heat exchanger tubes are replaced by vertical internals that serve as placeholder. The influence of vertical internals on the bubble properties for different spatial configurations (square and circular arrangements) is investigated in addition to measurements without internals. Furthermore, the hydrodynamic results of the Ø 22 cm column are compared with an available data set which is based on measurements that were conducted in a column with an inner diameter of 14 cm. The objective of this paper is to provide measurement data for the scale-up process as well as for various computer models simulating a bubbling fluidized bed with vertical internals. It was found that the scale-up process from pilot plants to an industrial scale may be simplified if vertical internals are present, independently of the geometric arrangement.

Comparative analysis of liquid hydrodynamics in a co-current flow-through bubble column with densely packed internals via radiotracing and Radioactive Particle Tracking (RPT)

Bubble column reactors are widely used for gas-liquid operations and most often are fitted with vertical internals for appropriate heat transfer. Apart from these applications, cylindrical vessels with concentrically installed vertical tube bundles find major use in boiling water reactors. Most often, heat removal takes place in boiling water reactors by phase change of the flowing water, which results in a complex, axially developing and highly dynamic two-phase flow pattern. Though the hydrodynamics in a bubble column with vertical internals have been addressed in few publications, the characteristics of liquid phase mixing and turbulence over a wide range of operating conditions and dense configuration of the internals have not been reported thus far. The present communication addresses the hydrodynamic characteristics in bubble column equipped with dense internals over a wide range of superficial gas and liquid velocities. Experiments were performed using the air-water system in a 120mm I.D. bubble column with, and without internals, by varying the percent cross-sectional area covered by the internals. A non-invasive Radioactive Particle Tracking (RPT) method has been employed for estimating the hydrodynamic parameters and mixing characteristics have also been investigated using residence time distribution (RTD) studies with radiotracers. The experimental results obtained in this work indicates that the configuration of the heat exchanger internals, superficial gas, and liquid velocities have a strong effect on liquid phase hydrodynamics and mixing characteristics.

Study the effect of dense internals on the liquid velocity field and turbulent parameters in bubble column for Fischer–Tropsch (FT) synthesis by using Radioactive Particle Tracking (RPT) technique

In this study, the effects of the dense vertical internals on the liquid velocity field and turbulence parameters (Reynolds stresses, turbulent kinetic energy, and turbulent eddy diffusivities) are experimentally investigated for the first time by using advanced Radioactive Particle Tracking (RPT) technique. The experimental work was carried out in a Plexiglas bubble column with 5.5in. (0.14m) and a height of 72in. (1.83m) for the air-water system. In this work, thirty vertical Plexiglass internals of 0.5in. (0.0127m) outer diameter were used which covered ∼25% (typical for Fischer–Tropsch processes) of the total cross-sectional area of the column where they arranged as the triangular pitch of 0.84in. (0.0214m). The superficial gas velocities based on both total cross-sectional area and free cross-sectional area available for the flow were utilized (0.08, 0.2, and 0.45m/s), which covered the transition and churn-turbulent flow regime to meet the industrial applications of FT synthesis. The experimental data show that the presence of the internals at a given superficial gas velocity causes an increase in the axial centerline liquid velocity and a sharp decrease in turbulence parameters while the increase in superficial gas velocity in the presence of internals causes an increase in axial centerline liquid velocity and turbulent parameters. The obtained data are reliable as a benchmark data for validation computational fluid dynamics (CFD) simulation, and models.

Influence of vertical internals on a bubbling fluidized bed characterized by X-ray tomography

An ultra-fast X-ray tomographic scanner is applied to study the hydrodynamics in a bubbling fluidized bed with and without vertical internals (e.g., heat exchanger tubes). The objective of this study is to understand the influence of vertical internals on hydrodynamic properties such as bubble volume, size and velocity and to provide measurement data for the design and scale-up of catalytic bubbling fluidized bed reactors with vertical internals. With these new measurements, correlations of bubble properties can be developed to reliably scale-up bubbling fluidized beds with vertical internals. For the investigated reactor with Geldart A/B particles, no relation between bubble size and velocity was observed for individual bubbles, i.e.; smaller bubbles tend to rise with higher velocities. A significant reduction in bubble size and sharpening of the bubble size distribution was generally obtained for a bed with vertical internals.