Mohammed AlMesfer+, Moses Kagumba++ and Muthanna Al-Dahhan*
*Chemical and Biochemical Engineering Department
Missouri University of Science and Technology, Rolla, Missouri 65401, U.S.A
+Chemical Engineering Department, King Khalid University, Saudi Arabia
++Chemical Engineering Department, Kenya Technical University, Kenya

This work presents the recent advances on the integrated effects of dense internals on bubble dynamics, heat transfer, phase’s distribution, liquid/slurry velocity field and turbulent parameters in slurry bubble columns for Fischer-Tropsch synthesis to produce clean alternative fuels. The experimental investigation have been performed using  four-point optical fiber probe for bubble dynamics, fast response heat transfer probe (for heat transfer coefficient), a hybrid measurement technique that combines both the four-point optical  fiber probe and advanced fast response heat transfer probe for simultaneous measurement of the related parameters, gamma-ray computed tomography (CT) and radioactive particle tracking (RPT) techniques. The obtained results suggest that the presence of internals enhances the heat transfer coefficient, axial dispersion coefficient, large-scale liquid/slurry recirculation velocity and specific interfacial area. The dense internals also enhances the bubble passage frequency, both local and overall gas holdup but leads to a decrease in bubble sizes and a decrease in axial bubble velocity (upward and downward). The influence of internals is more pronounced at lower superficial gas velocity than it is in the churn turbulent flow regime of higher superficial gas velocity. It has also been demonstrated that some of the related bubble dynamics results such as the gas holdup obtained in empty columns operated in the churn turbulent flow regime can be extrapolated to bubble columns equipped with dense internals by matching the superficial gas velocity based on the free cross-sectional area available for flow only. In addition, the presence of internals, at any given superficial gas velocity, results in an increased magnitude of the liquid centerline and negative axial velocity. On the other hand, a sharp decrease in the normal and shear liquid stresses, eddy diffusivity and liquid turbulent kinetic energy profiles occurs in the presence of internals. In this invited presentation the results and findings will be presented and discussed.