The repeatability and uniformity of 3D fluidized beds

Hydrodynamic characterization of fluidized beds is vital to many industrial processes, including the production of biofuels, pharmaceuticals, and numerous petroleum products. Local time-average phase fractions can be quantified in these multiphase three-dimensional systems using X-ray computed tomography (CT). This paper describes repeatability and uniformity measurements in a 3D 15.2 cm diameter cold flow fluidized bed using CT imaging to quantify gas holdup. Two different bed materials and a range of superficial gas velocities are investigated. Five tests over different days are completed to show repeatability for each test condition. Highly repeatable local time-average gas holdup is recorded at various locations within the bed for each material over all flow conditions. Uniformity is determined by analyzing the local time-average gas holdup at 12 azimuthal locations for both materials and various flow conditions. Uniform axi-symmetric fluidization is observed for each material and Ug when the bed height is greater than h = 0.25D, where the effects of individual aeration holes dissipate.