Effects of Sparger and Internals Designs on the Local Hydrodynamics in Slurry Bubble Column Reactors Operating under Typical Fischer-Tropsch Process Conditions - I

Our rigorously validated Computational Fluid Dynamics (CFD) model (Basha Omar, M., L. Weng, Z. Men, and I. Morsi Badie. 2016. CFD Modeling with Experimental Validation of the Internal Hydrodynamics in a Pilot-Scale Slurry Bubble Column Reactor. International Journal of Chemical Reactor Engineering 14(2): 599-619), was used to predict the effects of spargers design and internals configuration on the local hydrodynamics and flow structure in a pilot-scale (0.3-m ID) and a large-scale (10-m ID) Slurry Bubble Column Reactors (SBCRs), operating under Fisher-Tropsch (F-T) process conditions. In the pilot-scale SBCR without internals, the 6-arms spider created small/fast liquid recirculations in the vicinity of the sparger and slow/large liquid recirculations at about 1.2 times reactor diameter, whereas, the 3-concentric-rings and perforated plate spargers created slow/large recirculations throughout the reactor. In the pilot-scale SBCR with internals, spargers with downward-pointing orifices created larger Sauter mean bubble diameters (ds), leading to more effective solids suspension when compared with those with upward-pointing orifices. Also, 3-concentric-rings spargers resulted in larger Sauter mean bubble diameter values when compared with those of 6-arms spiders. In the large-scale SBCR provided with a large 3-concentric-rings sparger, the effects of vertical parallel and bundled internals on the local hydrodynamics and flow structures were predicted. Bundled internals led to slower and smaller liquid recirculations, smoother radial gas holdup profiles, larger average gas bubbles size, and smaller local gas holdups, when compared those predicted when using parallel internals.