Process
Spray drying is a very widely applied, technical method used to dry aqueous or organic solutions, emulsions etc., in industrial chemistry and food industry. Dry milk powder, detergents and dyes are just a few spray dried products currently available.
Spray drying can be used to preserve food or simply as a quick drying method. It also provides the advantage of weight and volume reduction. It is the transformation of feed from a fluid state into a dried particulate form by spraying the feed into a hot drying medium. Intensive research and development during the last two decades has resulted in spray drying becoming a highly competitive means of drying a wide variety of products. The range of product applications continues to expand, so that today spray drying has connections with many things we use daily.
Spray drying involves evaporation of moisture from an atomised feed by mixing the spray and the drying medium. The drying medium is typically air when working with aqueous solutions and nitrogen in case of organic solvents. The drying proceeds until the desired moisture content is reached in the sprayed particles and the product is then separated from the drying gas. The mixture being sprayed can be a solvent, emulsion, suspension or dispersion.
- Particles are separated using the cyclone principle: the particles are collected on the wall due to centrifugal forces and the cleaned air is forming a core vortex stream.
