Drying characteristics of fine powders in an inert medium circulating fluidized bed

The effects of inlet gas velocity (1.53-1.75 m/s), inlet gas temperature (50-80°C), mass ratio between fine powder and inert particle (F/I ratio, 0.05-0.2) and initial water content (8.5-31.6 wt%, wet basis) on the drying rate were determined in an inert medium circulating fluidized bed (0.085 m ID × 1.0 m high). Glass beads (d_p = 327.5 μm, ρ_s = 2,500 kg/m³) as inert particles and poly methyl methacrylate (PMMA) beads (d_p = 12.5 μm, ρ_s = 1,190 kg/m³) as fine powders were used. The drying rate increases with increasing inlet gas temperature, gas velocity and the F/I ratio. The effect of initial water content on the drying rate was negligible compared with the other variables. The obtained drying rate data have been correlated with inlet gas temperature, gas velocity, F/I ratio, and the initial water content.