Typical Large Spray Drying Systems

The essential elements of the spray dryer: atomizer, air disperser, drying chamber, inlet and exhaust air handling are combined into a system that meets individual operational safety, environmental protection, and powder handling requirements. All systems can be provided with post-treatment equipment: fluid bed dryer/cooler, agglomerator, de-duster and conveyor.

Open Cycle Spray Dryer System Open Cycle Features once-through airflow with exhaust to atmosphere. The majority of industrial spray dryers handle aqueous feedstocks and use this system. Both direct and indirect air heating are applicable. Exhaust air is cleaned using combinations of cyclones, bag filters, electrostatic precipitators, and scrubbers before the air discharges to atmosphere.

Closed Cycle Spray Dryer System Closed Cycle features drying in an inert gas atmosphere where nitrogen recycles within the dryer. This system must be used for the spray drying of feedstocks containing organic solvents or where the product must not contact oxygen during drying. Closed cycle plants are gas and powder tight, and are designed to the strictest safety standards. The flammable solvent vapors are fully condensed and recovered in liquid form.

Semi-closed cycle Spray Dryer System Semi Closed Cycle features either the partial recycle mode (recycle of up to 60% of the exhaust air as inlet air to the dryer, for effective waste heat utilization) or the self-inertizing mode, where direct air heating and a minimal air bleed create the low oxygen atmosphere necessary for drying aqueous feedstocks that form explosive powder-air mixtures. If odor is generated during drying, the small volumes of air vented from the system can be effectively and economically incinerated.

Aseptic Spray Dryer System Aseptic features sterile feed atomization and air filtering systems. These dryers are used where any form of powder contamination must be avoided. They are fabricated to special standards of finish and operate under a slight positive pressure. Fully automatic cleaning and sterilization systems are available. Plant layout is integrated with the laminar flow packing room.