Impact of Internals on the Gas Holdup and Bubble Properties of a Bubble Column

Most industrial applications involving bubble columns require the addition of internals for heat exchanging. However, most academic research on bubble columns has been performed in hollow (empty) ones. Hence, the impact of internals on the hydrodynamics of a bubble column has been insufficiently studied in the open literature. Accordingly, this study focuses on investigating the effect of internals that mimic those used in methanol synthesis (5% covered cross-sectional area) and the Fischer−Tropsch (FT) process (22% covered cross-sectional area) on the local gas holdup, gas−liquid interfacial area, bubble chord length, and bubble velocity distributions. The investigations have been performed using a four point optical probe in an 8 in. diameter column. An air−water system was used with superficial gas velocities up to 20 cm/s. An increase in gas holdup and interfacial area was obtained upon insertion of the internals, although the impact of the less dense internals (5% covered area) was not significant. However, in the case of dense internals, the bubble chord length decreased, yielding a decrease in the bubble velocity.