Overcoming the gamma‐ray computed tomography data processing pitfalls for bubble column equipped with vertical internal tubes

Abstract

This study identifies and addresses some major pitfalls that are involved in the visualization and quantification of the gas‐liquid distributions and their profiles in a bubble column with internals using the gamma‐ray computed tomography (CT) technique. Some of these pitfalls encountered in the scanning of bubble columns with internals are using an improper reference scan, and applying the same experimental scanning procedure and mathematical relationships for estimating the gas holdup in the column without internals to the column with internals. The experimental results revealed that the selection of the inappropriate reference scan for CT experiments would significantly affect the reconstructed linear attenuation coefficient values and consequently the gas holdup results. Additionally, the reconstructed linear attenuation values showed good agreement with theoretical values when considering air as reference scans. However, disagreement is observed when using the empty column with internals as a reference scan. Moreover, it was found that using the proper reference scan eliminated the errors not only for the reconstructed linear attenuation coefficients but also for the gas holdup values near the wall region. Furthermore, the CT technique was capable of capturing the small thickness (5 mm) of the wall for phantom and bubble columns as well as the internals when the air was used as the reference scan. Finally, a new methodology has been implemented to exclude the internals from the cross‐sectional images, and the azimuthally averaged gas holdup profiles to provide accurate and reliable results for comparison and validation purposes for the bubble column with internals.

Study of Gas Holdup Distribution in Cylindrical Split Airlift Reactor by Using Gamma-Ray Densitometry (GRD)

“…Comparison of GRD results of gas holdup distribution in this investigation with the Computed tomography CT results [14,18,19] (previous studies) is essential for validation and verification this technique. The percentage of error between the values of gas holdup is measured by CT and GRD techniques and calculated by the following equation: Figure 8 shows these values present an accepted percentage error which have a maximum error value of about 18.5%, with a minimum value of 0.37% for gas holdup distribution at the medial level.…”

“…The gamma source measurement technique has been well established and has played an essential role in multiphase system, which is used in a variety of industries, including the petroleum industry [18,19].…”

Effect of a Triangular Configuration of Heat Exchanging Tubes on Local Heat Transfer Coefficient in Bubble Column Reactor

“…Figure 1 displays a diagram representation of the experimental setup for the BC with the heat-exchanging tubes. A bundle of thirty stainless tubes was designed and manufactured to occupy 25% of (cross saction area CSA) of the BC to simulate the industrial heat-exchanging tubes used in the manufacturing Fisher Tropsch reactor [26], [27]. The dimension of each tube is 12 mm in diameter and 190 cm in height.…”

Process intensification in multifunctional reactors: A review of multi-functionality by catalytic structures, internals, operating modes, and unit integrations

“…and Technology [23,27,[35][36][37][38] were actively involved in the hydrodynamic study of flows in bubble columns with the heat exchanging internals of various configurations (some configurations are shown in Figure 3). The designs provide heat removal to maintain isothermal and steady operations in processes like FT synthesis, where non-isothermal operations affect the desired product s selectivity and yield.…”