Industrial & Engineering Chemistry Research, Vol.50, No.12, 7549-7565, 2011
Measurements of Dispersion Coefficients for FCC Particles in a Free Board
Particle image velocimetry (PIV) experiments were performed noninvasively in the Illinois Institute of Technology (IIT) two-dimensional circulating fluidized bed (2-D CFB) of fluid catalytic cracking (FCC) particles to measure laminar and turbulent properties, near the front wall in the z-direction; at the center and near the right and left walls in the x-direction; and in the free board region in the y-direction. The PIV measurements were obtained simultaneously in the y- and x-axes, using a charge-coupled device (CCD) camera, with the aid of a colored rotating transparency. The instantaneous and hydrodynamic velocities were used to obtain laminar properties for particles and turbulent properties for clusters, respectively. Laminar and turbulent properties for solids conveyed anisotropy. The y-axis solids velocities, power spectral densities of hydrodynamic velocities, and granular temperatures were highest at the center in the x-direction. The mixing was on the level of particles. The y- and x-axes solids dispersion coefficients were several orders of magnitude lower than the literature values, because of the low particle velocities in the free board. However, total granular temperatures were reasonably close to the literature values.