A spray dryer is a machine used to convert a liquid or slurry into a dry powder by quickly evaporating moisture using hot gas. The basic components of a spray dryer include a feed system for delivering the liquid or slurry to be dried, a drying chamber, a hot gas generator, and a collection system for the dried powder.

The liquid or slurry is first fed into the spray dryer through a nozzle or atomizer, which breaks it down into small droplets. These droplets are then introduced into the drying chamber, where they are exposed to hot gas (usually air or nitrogen) that rapidly evaporates the moisture from the droplets.

As the droplets travel through the drying chamber, they lose moisture and shrink in size until they eventually become dry, solid particles. The dried powder is then collected in the collection system, which may include a cyclone separator or a bag filter, and is ready for packaging or further processing.

The temperature and flow rate of the hot gas, as well as the rate and composition of the liquid or slurry feed, can be controlled to achieve the desired particle size, shape, and density of the final product. Spray drying is commonly used in the food, pharmaceutical, and chemical industries to produce powders from liquids or slurries, such as milk, coffee, antibiotics, and detergents.