DRYFACTS

Issue – Oct-Nov-Nov 2007

Increase production without increasing capacity

Spray / Fluidized bed dryers require large quantities of hot air for drying. The quality of the final product is affected by the quality of air entering the dryer. It should be dry, free from contamination, foreign particles and odourless.

With the growing emphasis on limiting production losses and downtime, which impacts final product quality and thus profits, the importance of using dehumidifiers, in conjunction with Spray Dryer / Fluidized Bed Dryer for quality drying, has become almost mandatory. Moisture hinders the free flow of powders/ granules making many downstream operations (e.g. packaging, filtering, handling) difficult and expensive.

Speedier drying and processing with  dehumidifiers

Spray / Fluidized Bed Drying

Spray Dryer
A spray dryer, is a device for drying, utilizing a spray. It mixes heated air with an atomized (sprayed) liquid stream within a vessel (drying chamber) to accomplish evaporation and produce a free-flowing dry powder with a controlled average particle size.

Fluidized Bed Dryer
In a fluidized bed dryer, air is passed through the product layer under controlled velocity conditions to create a fluidized state. Heat may also be used by heating surfaces immersed in the fluidized layer. These dryers are widely used in the:

Food & Dairy Industry

  • Beverages – Coffee, Tea and Cocoa.
  • Carbohydrates and Sugar
  • Health foods and Herbal products
  • Juice/ soft drink concentrates and Soup mixes
  • Milk, Starch and Vitamins
  • Ingredients and flavours.

Dehumidification (Humidity Control) – A must  Solution
The ideal solution is to install a Bry-Air Desiccant Dehumidifier at the inlet ( source of air) of the spray/ fluidized bed dryer for a constant moisture content supply (dry) air inside the dryer.

Operating PrincipleThis helps in reducing the physical monitoring of the drying temperature and time thereby reducing costs and ensuring consistent quality year around. Bry-Air Dehumidifiers have been installed by leading manufacturers like Unilever, Tata Tea Ltd., Nestle, Mauri Food and Goodricke Group, for processing of coffee, instant tea, milk powder and other powdery products.

Spray DryingLow temperature drying
The Bry-Air Desiccant Dehumidifier is also ideal for many temperature sensitive products, which cannot be spray dried easily at relatively high inlet temperatures. Use of dehumidifiers also reduces the drying time of the product inside the spray / fluidized bed dryer. Bry-Air specializes in product drying at temperature below 24°C (75°F).

Processing of powdery foods
Food ProcessingIn processing powdery foods such as milk powders, the presence of moisture in the air can cause lumping or caking. This effects the free and easy movement of the food and beverage powders in the processing machine and pneumatic conveyors.

Due to high humidity, powdery material tends to stick to the hopper conveyors and packing machine, leading to frequent breakdowns in the conveyor drive mechanism. To ensure free flow of powder and avoid sticking of powder on chain conveyor and other machine parts.

Relative Humidity ( RH ) in the packing hall has to be maintained at 40±5% and temperature at 22-25°C. The solution to the problem lies in the introduction of a Bry-Air dehumidifier. The dehumidifier by controlling the relative humidity in the environment provides the most simple and economic solution to overcome lumping and caking. It also avoids the sticking of powder on packing machines, hoppers, and other parts. Moreover, it ensures an easy, free flow of powder through the packing machine into containers.