Bubble column and slurry bubble column reactors are widely used in chemical, petrochemical and biochemical processes, such as oxidation, methyl synthesis, Fischer Tropish (FT), waste water treatment, and fermentation. Many of these processes are exothermic and hence they require some means of heat removal like vertical heat exchanging tubes (internals) to remove the generated heat and to maintain the reactor at a desired temperature. Few studies in the open literature have been conducted to study the effect of internals on hydrodynamics and bubble characteristic in bubble column reactor concluding that the vertical internals significantly alter the hydrodynamics, mixing pattern, heat and mass transfer and hence the reactor performance. However, there is no work has addressed the impact of the gap between the internals and the gas distributor on hydrodynamic and bubble properties in bubble column. Accordingly, this work focuses on investigating the impact of the axial height of the internals from the gas distributor on the radial profile of local gas holdup, specific interfacial area, bubble velocity, bubble passage frequency, and bubble chord length by using 4-point optical fiber probe measurement technique in air-water system in a 6 inch Plexiglas column. Effect of dense internals with 0.5 inch in diameter covering 25 % of the cross sectional area to mimic FT synthesis at different heights (0.07D, 0.5D, 1D and 1.5D) from the gas distributer have been investigated at Different superficial gas velocity ranging from 3 to 45 cm/s covering bubbly, transition, and churn turbulent flow regimes. The result and the findings should be given in the presentation.

Key words: Bubble column, Internals, Gas hold up, Specific interfacial area, bubble velocity, bubble chord length.