Food Spray Dryer Manufacturers

Food spray drying — applications and technology

Spray drying converts a liquid feed (a solution, suspension, or slurry) into a dry powder by atomising the liquid into fine droplets and drying those droplets in a stream of hot air. The very high surface area of the fine droplets allows almost instantaneous evaporation and drying — in a matter of seconds, liquid droplets become dry powder particles. This rapid drying at a relatively moderate outlet temperature (despite high inlet air temperatures of 150–250°C) allows heat-sensitive products like dairy proteins, vitamins, and flavour compounds to be dried with less damage than slower drying methods. Food spray drying applications include: dairy powders (whole milk powder, skimmed milk powder, whey powder, infant formula, cheese powder); instant coffee and tea (soluble coffee from liquid concentrate; instant tea); egg powder; flavour encapsulation; and specialty food ingredient powders. Two main atomiser types are used: rotary disc atomisers (a high-speed spinning disc shatters the feed liquid into fine droplets — used for most dairy and food powder applications; produces spherical, free-flowing powder); and pressure nozzle atomisers (the feed liquid is pumped at high pressure through a nozzle orifice — used where specific particle size or for abrasive feeds).