Analysis of particle coating by spouted bed process

Abstract

The coating of nearly spherical porous alumina with a mean diameter, d P , of 3.9 mm, with a suspension of sucrose and talc in water, was carried out in a conical-cylindrical spouted bed. The rate of increase in particle mass, K 1, and the mass fraction of atomized solids incorporated by the particles, η, were measured as a function of spouting gas temperature, T gi,mass flow rate of atomized suspension relative to spouting gas, W s/ W g, and the gas flow rate relative to minimum spouting, Q/ Q ms. The spouting gas temperature was varied between 67 and 83°C, W d/ W g between 0.00263 to 0.00471, and Q/ Q ms between 1.5 and 1.7. K 1 and η were found to be insensitive to T gi within the studied range; expressions for their dependence on W s/ W s and Q/ Q m, were derived. Particle mass increased linearly with the coating time. The final product is uniform in shape and conserves a log-normal particle mass distribution.