EXPLANATION

Spray dryer is a continuous method of drying solutions, slurries and pastes in the shortest possible time. The quick drying is achieved because the liquid is atomised as fine droplets in a chamber through which the current of hot air is passed. Because of atomisation, every large surface area is created for the heat and mass transfer occurring on the surface of the droplet. And hence drying is extremely quick. The hot air coming in contact with the droplets increases its temperature only up to wet bulb temperature of air. The above features make the industrial spray drying plant suitable for the following

Continuous production
Large throughputs
Heat Sensitive material
Fully enclosed operation guarantying purity.

• Continuous production
• Large throughputs
• Heat Sensitive material
• Fully enclosed operation guarantying purity.

Industrial Spray Drying - PRINCIPLE

In counter current flow system, the atomization takes place at the top of the spray dryer and the hot air enters from the bottom. 'The spray of liquid gets dried and dried product is removed from the bottom. Counter-current flow guarantees maximum heat economy. But in such systems, the dried product comes in contact with the hot air and is exposed to excessive heating, charring, degradation etc.
This danger is greatly reduced in co-current system, Though hot air comes into contact with the atomised material, the temperature of the material never exceeds wet bulb temperature of air. However the height of the spray dryer has to be high since sufficient time of contact has to be given Sometimes a golden mean is struck by employing mixed flow patter when atomisation occurs at the bottom throwing the spray upwards towards the hot air distributor in counter current fashion. After the spray loses its force and falls by gravity it follows cocurrent pattern.

Industrial Spray Drying - OPERATION

Hot air is produced with the help of a hot air generator working on either Fuel oil, Diesel, CNG or other fuel source . The hot air is initially passed through the chimney to remove the black smoke and then is introduced in the spray drying chamber. Once the desired temperature is generated at the outlet of the spray dryer the feed is introduced to the drying chamber through the atomiser. The atomised particles come in contact with the hot air for the designed period of time the moisture is totally removed. It is carried along with the draft of air through the and is removed from the outlet through a rotary air lock valve.

Industrial Spray Drying -APPLICATION

Food , Soap / Detergent , ceramics, plastics, Tannins and off recently effluent slurries. Depending on the application, it is possible to have variation in the drying circuitry and to offer a tailor made system to suit the purpose.