Spray drying

Spray drying turns a liquid feed into dry powder by atomizing it into droplets and rapidly evaporating the solvent with hot gas. It is widely used to produce powders from food, pharmaceutical, and chemical formulations.

Atomization: The breakup of a liquid into fine droplets or a spray. The atomizer sets the droplets’ size and distribution, shaping drying time and powder properties.
Milk powder: A dried dairy product made by removing most water from milk or milk concentrates. Spray drying is a principal industrial method for producing milk powders.
Freeze-drying: A drying process that freezes material and removes ice by sublimation under reduced pressure. It better preserves some heat-sensitive structures but is usually slower and more costly.
Drying: The removal of liquid from a material by evaporation, sublimation, or another separation process. Spray drying is a rapid, droplet-based form of drying.
Evaporative cooling: Cooling caused when a liquid absorbs energy to become vapor. Rapid solvent evaporation keeps wet droplets cooler than the surrounding hot gas.
Instant coffee: Dried coffee extract designed to dissolve quickly in hot water. Spray drying converts brewed coffee extract into soluble powder, alongside freeze drying.
Drum drying: A process that dries a thin layer of feed on the surface of heated rotating drums. It uses direct contact with hot surfaces rather than atomized droplets in hot gas.
Psychrometrics: The study of the thermodynamic properties of air–water vapor mixtures. Inlet humidity and temperature govern the gas’s capacity to accept evaporated moisture.
Residence time: The time material spends inside a process vessel or system. Droplets must remain in the chamber long enough to dry before collection.
Microencapsulation: Enclosing small particles or droplets within a protective coating or matrix. Spray drying can trap flavors, oils, or sensitive ingredients inside a dried carrier matrix.

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