Computed Tomography (CT) and Computer-Automated Radioactive Particle Tracking (CARPT) Were Used to Study the Gas Distribution and Incipient Particle Motion in a Packed/ebullated Bed in Which Gas and Liquid Are in Cocurrent Upflow. CT Scans Were Performed to Evaluate the Gas-Liquid Distributor and Gas Sparger for the Experiments, using a Perforated Plate Gas-Liquid Distributor (With 96 1-Mm Holes, Open Area of 0.1%) and a Gas Sparger (Cross-Shaped, with 16 3-Mm Holes), the Cross-Sectional Gas Holdup Distribution in the Packed/ebullated Bed Was Relatively Uniform, with Gas Holdup of About 0.11 in the Center and 0.09 Near the Wall of the Bed at Superficial Gas and Liquid Velocities of 2 and 0.3 Cm/s, Respectively. the Cross-Sectional Averaged Gas Holdup Was 0.095. CARPT Experiments Were Utilized in an Air - Water - Ethanol - (10 Wt. %) Solids System to Identify the Operating Conditions at Which Solid Particles First Start to Move in the Bed. at a Superficial Gas Velocity of 1. 7 Cm/s and Superficial Liquid Velocity of 0.3 Cm/s, Solids Particles in the Bed Started to Move and Travel Long Distances in the Axial Direction. CARPT Experiments in the Same System at Superficial Gas Velocity of 2.0 Cm/s and Superficial Liquid Velocity of 0.3 Cm/s Showed that the Solid Particles in the Bed Were Moving Significantly throughout the Column, Generating a Recirculation Pattern with Upflow in the Center and Downflow Near the Wall of the Column. the Time-Averaged Maximum Upward and Downward Velocity of the Tracer Particle Was About 0.47 and 0.57 Mm/s, Respectively.


Chemical and Biochemical Engineering

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Article - Journal

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Publication Date

01 May 2001