DRYING OF MICROPARTICLE SLURRY AND SALT-WATER SOLUTION BY A POWDER-PARTICLE SPOUTED BED

Adhesion and agglomeration between fine particles and coarse particles are very strong for fine particles under several microns in diameter, The powder-particle spouted bed (P-PSB) was developed as a new type of dryer for continuous drying of microparticles under several microns i n diameter. The powder-particle spouted bed dryer is a cone-bottomed f luidized bed without a gas distributor. Coarse particles were loaded i nto the dryer and the hot gas was fed to it from the cone-bottom so th at coarse particles were fluidized violently, and a microparticle slur ry and a salt-water solution were continuously fed to it. Continuous d rying of a microparticle slurry and a salt-water solution were carried out by using the powder-particle spouted bed, and the drying characte ristics were investigated. The moisture content of the microparticles dried by this process from the submicroparticle (under 1 mu m in diame ter) slurry and the salt-water solution were nearly equal to their equ ilibrium moisture content over the range of the experiment, When the d rying efficiency was above 60%, agglomerates were observed in the bed, The relative humidity of the outlet gas and the drying efficiency can be calculated by mass and heat balances across the bed.