Validation of the new mechanistic scale‐up of gas‐solid fluidized beds using advanced non‐invasive measurement techniques

Abstract

AbstractThis study focuses on the validation of a new mechanistic of scale‐up for hydrodynamics similarity of gas‐solid fluidized bed reactors that was developed in our Multiphase Reactors Engineering and Applications Laboratory (mReal). It is based on maintaining identical or relatively similar time‐averaged radial profiles of gas holdups in two differently sizes gas‐solid fluidized beds to achieve local and global similarities of the dimensionless hydrodynamic parameters. This is because the gas‐dynamic dictates the hydrodynamics of gas‐solid fluidized beds. The new scale‐up method has been successfully validated by assessing for the first time the local hydrodynamic parameters, such as time‐averaged cross‐sectional distributions and radial‐profiles of gas and solids holdups at different axial levels, which were measured by gamma‐ray computed tomography technique. In addition, the particle velocity field and turbulent parameters (shear stress, normal stresses, and turbulent kinetic energy) were measured by radioactive particle tracking technique. The experimental results showed that achieving similarity in the radial profiles of the gas holdup in the geometrically similar beds is essential for ensuring identical or relatively similar local and global hydrodynamics similarity. As the differences increase in terms of magnitude and trend in the gas holdup radial profiles between two beds, the differences increase in the detailed hydrodynamics.