DRYING OF MATERIALS OF HIGH-MOISTURE CONTENT IN MECHANICALLY SPOUTED BED DRIER

Drying of suspensions and paste-like materials on inert particles in t he Mechanically Spouted Bed (MSB) drier was studied by the author. Rad ioactive isotopic tracer technique was used for measuring the Cycle Ti me Distribution (CTD) of the inert particles. Effect of gas velocity a nd peripheral speed of the houseless screw was studied on variance (si gma2) of CTD. It was found that solid particle circulation could be ch aracterized by plug flow. The three partial processes of drying on ine rt particles, namely: coating of the particles, drying of coating and abrasion of dried layer, could be separated in space in the MSB drier. In order to provide steady state conditions of drying it is important to predict the time required by the partial processes. Heat and mass transfer coefficients were calculated on the drying model.