Working Principle

The sealed circulation spray drying system operates in a fully sealed environment. Inert gas such as nitrogen (N₂) is commonly used as the drying medium. It is suitable for materials containing organic solvents, toxic components, and easily oxidized substances.
By adopting inert gas as the circulating medium, the materials are effectively protected from oxidation. The inert gas circulates in the system after dehumidification treatment. Nitrogen is heated and then delivered into the drying tower. The liquid material is pumped to the centrifugal nozzle by a screw pump and atomized into fine liquid mist. Heat and mass transfer is completed inside the drying tower.
Dry finished products are discharged from the bottom of the tower. The evaporated organic solvent vapor is extracted by fan-generated vacuum. Solid powder is separated through a cyclone separator and spray tower. Saturated organic gas is condensed and recovered by a condenser, while uncondensed gas is continuously reheated and recycled into the system.
Different from ordinary centrifugal spray dryers which adopt open air conveying and exhaust modes, this explosion-proof sealed circulation centrifugal spray dryer takes nitrogen as the drying medium and maintains positive pressure inside the system. A pressure transmitter automatically controls the nitrogen intake volume to keep the internal positive pressure stable during operation.

Schematic of structure

Technical Parameter

Dry powder recovery rate: ≥95%
Product residual solvent: ≤2%
System oxygen content: ≤500 ppm
Explosion-proof grade: Ex d IIB T4
Operating state: System runs under positive pressure

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