Evaporation and drying of drops in superheated vapors

Abstract

The evaporation of pure liquid drops and the drying of drops containing suspended and dissolved solids in an atmosphere of superheated vapor were studied. Changes in the weight and temperature of approximately 2 μliter drops of four food products, five miscellaneous materials, and pure water were measured as evaporation and drying proceeded at different drying temperatures. Evaporation of water was found to take place more slowly in superheated steam than in air. However, the medium, in which faster drying occurred, depended upon the material being dried. No major differences between the final products were observed for these two drying media except that some materials yielded denser particles in superheated steam than in air.