CPF-Process for Powder Generation from Liquids

Liquids can be transferred into powdery products by combining them with solid carriers. Beside the classical mixing processes a widely applied technology is the so called fluid bed technology, where liquids are sprayed on solid carriers. Typical concentrations of liquids in the powdery end products are 2-10 wt%. For some special applications also higher concentrations of approx. 50 wt% may be obtained.

The CPF-Technology (Concentrated Powder Form) allows to obtain powders with liquid concentrations of up to 90 wt%. Therefore a gas, normally carbon dioxide, is dissolved under high pressure (70 up to 200 bar) in the liquid, which has to be powdered. Then the gas saturated solution is rapidly expanded. The gas is set free and very fine droplets of the liquid are formed. During the expansion a powdery carrier is added cocurrently to the sprayed liquid. The expanding gas causes an intensive mixing between the fluid droplets and the solid carrier. The liquid may be adsorbed on the solid surface or in case of porous carriers, the fluid pours into the cavities and soaked particles are formed.

Primary aim during the development of the CPF-process was to obtain free-flowing powdery products. The technology was tested using different liquids (essential oils, extracts, oleoresins) as well as carriers (starches, silic acids, celluloses). The experimental results showed, that the CPF-process can be applied to low and high viscous liquids and to solid carriers with a broad range of particle sizes and bulk densities (50 –850 kg/m³).