(344b) The Effect of Internals and Solids Loading On the Bubble Dynamics in a Slurry Bubble Column

Slurry bubble columns have been used in wide range of applications in industry such as the Fisher-Tropsch synthesis and many others. Effects of solids loading in the presence of heat exchanging internals on the bubble dynamics are lacking in the open literature. Therefore the focus of this study is to investigate the effects of dense internals and solids loading on the bubble dynamics such as; specific interfacial area, local and overall gas hold-up, bubble velocity, bubble frequency and bubble chord lengths using four-point optical probe. The experimental work is carried out in 0.14 m diameter Plexiglas bubble column with air-water and air-water-glass beads (particle size of 150 μm and density of 2500 kg/m³). The superficial gas velocities based on free area for the flow were in the range of 0.03 to 0.45 m/s and solids loading were varied up to 40 % vol. The internals (0.5 inch diameter) occupied 25 % of column cross- section area. The experimental data showed that the local and overall gas hold-up decreases with increasing solids loading. Similar trend was also observed for gas-liquid interfacial area for all the studied superficial gas velocities. Moreover, there is no significant effect of solids loading on the bubble chord length.  With internals and when the four-point optical probe was placed in the center of the column at the fully developed flow regime, it has been found that at low superficial gas velocity range (bubble flow regime), the addition of solids enhances the bubble velocity. However, at high range of superficial gas velocity (churn turbulent flow regime), the addition of solids decreases the bubble velocity. Further solids loading have no significant effect on the bubble velocities except when the solids concentration is 40% vol where the bubble velocities decrease further by up to 10 %. Detailed results and findings will be discussed in the presentation.