Spray Drying

General Description

In spray drying, a slurry or liquid solution is dispersed into a stream of hot gas in the form of a mist or fine droplets. Moisture is rapidly vaporized from the droplets, leaving residual particles of dry solid, which are then separated from the gas stream. In a typical spray dryer, the chamber is a cylinder with a short conical bottom.

Equipment Sizing

In Design Mode, the user specifies the specific evaporation rate (expressed as rate per unit volume of equipment) and the program calculates the equipment volume by dividing the total mass flow rate of evaporated components by the specific evaporation rate. In addition, the user specifies the height/diameter ratio of the equipment and the program calculates the equipment height, diameter and volume. If the calculated diameter exceeds the specified maximum diameter, then multiple units are assumed that operate in parallel. In Rating Mode, the user specifies the equipment height and diameter, and the program calculates the equipment volume. Then, by default it calculates the specific evaporation rate. However, if the process and procedure operating modes are set to batch, then the user may choose to either specify the drying time and let the program calculate the specific evaporation rate or specify the specific evaporation rate and let the program calculate the drying time.