A SCACE-UP STUDY OF NOZZLE TOWER SPRAY DRYERS

A quasi-one dimensional model taking into account hindered drying beyond the critical tmisture content and droplet size distribution is used to scale-up nozzle tower type of a spray dryer with uniformly distributed air entry, based on pilot plant data. A pilot plant with 8 m high and 1.7 m diameter spray dryer is used to collect the drying data. Equilibrium and critical mistwe contents of the particles are also experimentally msured. The index of drying rate in the hindered drying period is calculated frun the pilot plant data. This index is used in the M e 1 to determine the drying capacity and thereby the mixinnnn particle size that can be produced ina 3.5 m dimoeter 12 m high nozzle t- type of spray dryer. Experiments are carried out in this spray dryer to verify the calculated values of the spray drying capacity. It is s h m that the model when used along with the pilot plant data is adequate for scale-up calaculations for nozzle taer type of spray dryers.