Spray Dryer
Spray dryers are devices used in spray drying. It takes a liquid stream and separates the solute or suspension as a solid and the solvent into a vapor. The solid is usually collected in a drum or cyclone. The liquid input stream is sprayed through a nozzle into a hot vapor stream and porised. A nozzle is usually used to make the droplets as small as possible, maximising heat transfer and the rate of water vaporisation. Droplet sizes can range from 20 μm to 180 μm depending on the nozzle. Spray dryers can dry a product very quickly compared to other methods of drying.
Spray Dryers are custom built designs having various atomization and flow patterns to suit the feed and product characteristics and can be used for drying of versatile range of products.
Spray Drying is a single step drying operation in which liquid feed solutions, emulsions, dispersions or slurries are directly converted to free flowing powder or granules. Read more about spray dryers and our services in relation to spray dryers below
Rotary Disc Atomisation
A high speed rotating disc is used for atomizing the liquid feed. The disc throws the liquid outward tangentially at high velocities forming fine droplets / mist by impacting with relatively slow moving hot air. Instant drying takes place due to extremely large surface area to volume ratio converting liquid/slurries into free flowing dry powder.
Discs designs include straight / curved vanes, pin wheels, multilayer discs in diameters of 60 mm, 100 mm, 160 mm, 250 mm & 350 mm for different capacities.
For high temperature applications special water cooled bearing arrangements are available.
Nozzle Atomisation
Feed solution or slurry at high pressure is atomized through a nozzle into fine droplets and then dried instantaneously. Various types of airflow patterns are possible with nozzle atomization systems. Nozzle type spray dryers are used to produce material in the granular, non-dusty or powder form as required.
Depending on the desired physical properties of end product, the choice of co-current, counter current or mixed air flow is selected.
Features
- Wide range of materials can be dried
- Options of both single fluid / two fluid nozzles
- Easy to operate and user friendly
- Compact layout
- Automatic / remote nozzle change over with steam / air flushing
- Explosion Vents, Fire Fighting Nozzles, Pressure Designs
- Inert Atmosphere Drying
Closed Loop Spray Dryers
Closed loop spray dryers are used when the product to be dried is oxidisable or laden with flammable / explosive solvents, nitrogen purged. In this case, closed loop systems are preferred.
Advantages
- Ideal for solvent laden, flammable / explosive product to be dried
- Inert gas drying avoids oxidizing of material
- Recovery of costly solvents
Air Broom & Wall Cooling
Wall cooling arrangements are provided on Spray Chambers handling products of thermoplastic nature. The arrangements include and external cooling air jacket and / or internal rotating arms with air jets to form AIr Bloom on the chamber wall.
Advantages
- These Spray Dryers are ideal for thermoplastic, heat sensitive, hygroscopic products