Entrainment of Geldart C particles in fluidized beds with binary particles

摘要

The effects were determined of the mass ratio of Geldart C particles on the total amount of particles (M-fine/M-total=0-50 wt%), superficial gas velocity (U-g=0.5-1.0 m/s) and coarse particle size distribution (mono, binary, flat, and Gaussian type) on entrainment of Geldart C particles in a bubbling fluidized bed with binary particles (coarse particles: d(p) = 0.512 mm, rho(s) = 2,339 kg/m(3) and Geldart C particles: d(p) = 13 mu m, rho(s) = 4,455 kg/m(3)). The initial entrainment rate increases with increasing U-g. At U-g of 0.5 and 0.7 m/s, the initial entrainment rate slightly increases initially and then remains almost constant with increasing mass ratio (M-fine/M-total). At higher gas U-g of 0.85 and 1.0 m/s, the initial entrainment rate increases with increasing the mass ratio (M-fine/M-total) up to 30 wt%, after which the increasing slope of the initial entrainment rate decreases with increasing the mass ratio (M-fine/M-total). Also, the decrease in the coefficient of entrainment rate is equal to the increase in (M-fine/M-total) at the corresponding U-g. The average particle size of the entrained particles is about 12-16 mu m at U-g of 0.5-1.0 m/s.