Ruiskukuivaus

Ruiskukuivaus is a drying process widely used in various industries to convert a liquid or slurry into a dry powder. This technique involves atomizing the liquid feed into a fine spray within a hot drying chamber. The tiny droplets are then rapidly exposed to hot air, causing the solvent, typically water, to evaporate almost instantly. As the solvent evaporates, the solid particles are left behind, falling to the bottom of the chamber as a dry powder.

The equipment used for ruiskukuivaus, often referred to as a spray dryer, consists of a drying chamber, an atomizer (which can be a rotary atomizer or spray nozzles), an air heater, and a collection system for the powder. The process is highly efficient due to the large surface area of the atomized droplets, facilitating rapid heat and mass transfer. The particle size, shape, and density of the resulting powder can be controlled by adjusting parameters such as feed rate, atomization speed, air temperature, and airflow.

Ruiskukuivaus is employed in the production of a diverse range of products, including food ingredients like milk powder, coffee, and flavorings, as well as pharmaceuticals, ceramics, detergents, and chemicals. Its advantages include speed, continuous operation, and the ability to produce powders with desirable properties such as good flowability and solubility. However, it is not suitable for heat-sensitive materials that might degrade under high temperatures, although lower operating temperatures can sometimes mitigate this.