(3a) On the Hydrodynamics of Bubble Columns with Internals for Liquid Fuels Syntheses

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. Gas holdup and bubble dynamics including local bubble holdup, gas-liquid interfacial area, bubble length, bubble velocity, and others are important parameters on which the performance of bubble columns depends. Accordingly, this study focuses on investigating the effect of internals that mimic the ones used in methanol synthesis (5% covered cross-sectional area) and Fischer-Tropsch (FT) process (22% covered cross-sectional area) on the local gas holdup, gas-liquid interfacial area, the bubble chord length and bubble velocity distributions. Measurements were made via a four point optical probe in a 8? diameter column using an air-water system. Gas superficial velocities applied were 3, 8, and 20 cm/s. An increase in gas holdup and interfacial area was obtained upon insertion of the internals. It is to be noted that, the impact of the less dense internals arrangement (5% covered area) was not significant. However, the bubble chord length and the bubble velocity decreased in the case of dense internals arrangement.