Spraytørring

Spraytørring is a drying process where a liquid is atomized into fine droplets into a hot gas stream. As the droplets fall through the drying chamber, the liquid evaporates, leaving behind dry powder particles. This method is widely used in various industries to produce powders from solutions, suspensions, or emulsions.

The process begins with the liquid feed being pumped to an atomizer, which can be a rotating disc or a nozzle. The atomizer breaks the liquid into small droplets, increasing the surface area available for evaporation. These droplets are then introduced into a drying chamber where they come into contact with hot air or other gases. The heat from the gas causes rapid evaporation of the solvent, typically water, from the droplets. The dry powder particles are then separated from the gas stream using cyclones or bag filters.

Spraytørring is advantageous because it is a rapid process that can handle heat-sensitive materials due to the short contact time with the hot gas. It allows for good control over particle size and morphology, resulting in uniform powders. The process is continuous and can be scaled up for industrial production. Common applications include the production of milk powder, instant coffee, detergents, ceramics, and pharmaceuticals. The choice of atomizer, drying temperature, and gas flow rate are critical parameters that influence the final product's characteristics.