Summary: closed cycle spray dryer is dedicated to  the suspensions  made from such organic solvents as ethanol, acetone, hexane, gas oil etc., a closed circulation type spray drying process of product with inert gas (or nitrogen) as drying media . Products have no oxidation, medium recyclable, and inert gas (or nitrogen) can be recycled in entire process. The closed cycle system designed for recovery of organic solvent, its requirements of explosion-proof control are very high to the system, with high performance of systemic automatic control, strict GMP demands. Commonly used in spray drying for fine ceramics, pharmaceuticals, battery materials, powder of carbide alloy (Wc.Fe).

 Closed spray drying system is also called close cycle spray drying system, the features of which are composed of a closed cycle loop by system, so that the heat carrier can be recycled. For drying those materials in which the volatile is organic chemistry solvent, toxic or they can cause harms on personal and environment after escaping ,because the  materials contain organic solvents in the liquid or products are easily oxidized, flammable, explosive ,generally , the materials which require this process can not contact with oxygen , so use of the heat carriers mostly are inert gases ( such as nitrogen, carbon dioxide, etc. ) . The tail gas discharged from the dryer, after gas-solid separation, go through the condenser to recover solvent or remove moisture, after temperature rising with a heater then entering into the dryer for recycling. Such a dryer in the system increases the refrigeration equipment, with high operating costs, high tightness requirements to equipment. Ordinary pressure or slightly positive pressure is mainly in the dryer, to prevent air from entering the system.

Working principle: Closed cycle spray drying equipment is operated in a closed environment , and the drying medium is an inert gas ( or nitrogen ) ,suitable to dry organic solvent material, toxic materials or the ones prone to oxidize during drying process; The system uses inert gas as circulating gas, has a protective effect on the dry material, and the circulating gas goes through the processes of loading humidification and dehumidification, so the media can be reused; After nitrogen is heated by a heater, entering the drying tower, liquid materials then are delivered to the centrifugal nozzles by a screw pump. The liquid is atomized into powdery material by a high-speed cycle atomizer, then discharged from the bottom of the tower, and under a negative pressure of an air blower, the organic solvent gas evaporated discharges the dust of entrained in the gas, through a cyclone separator, and the saturated organic solvent gas, after removing dust with a spray tower, condensed into liquid by a condenser, out from the condenser. Non-condensable gas mediums as a drying carrier are to recycle for use in the system after continuous heating. While the conventional ordinary centrifugal spray drying is to achieve the  goal of removing moisture through continuous delivering and exhausting wind, and this is a significant difference between the explosion-proof type closed centrifugal spray drying equipment and ordinary centrifugal spray drying equipment; The interior of drying system for operating is positive pressure ,maintaining a certain pressure value , if the internal pressure drops, this is done to automatically control the feed amount with a pressure transmitter, to ensure the pressure is in balance in the system.