Bry-Air Dehumidifier helps increase throughput of Spray Drying of instant coffee at HUL by 20%

Spray drying produces spherical particles of about 300 micro metre (0.012 in) size with a density of 0.22 g/cm³. To achieve this, nozzle atomization is used. Various ways of nozzle atomization can be used, each having its own advantages and disadvantages. High speed rotating wheels operating at speeds of about 20,000 rpm are able to process up to 60,000 pounds (27 tonnes) of solution per hour.

• Completed in 5-30 seconds (depending on factors such as heat, size of particle, and diameter of chamber).
• Moisture content change: IN = 75-85% OUT = 3-3.5%

Challenges in Spray Drying

Spray dryers require large quantities of hot air for drying. The quality of the final product is affected by the quality of inlet air entering the dryer. The Spray Dryer mixes heated air with an atomized (sprayed) liquid stream within a vessel (drying chamber) which leads to evaporation and produces free-flowing dry powder with a controlled average particle size. Thus, the inlet air has to be dry, free of contamination, foreign particles and odourless. However, since the ambient changes throughout 24 hrs, 365 days a year, the humidity present in the air, entering the spray dryer is not constant. Thus, the drying temperature and time inside the dryer needs close monitoring to restrict loss due to varying levels of humidity present in the inlet air. These varying inlet conditions need to be monitored by an experienced operator to adjust the parameters for a stable outlet condition.

• Throughput varies with outside environmental conditions
• Extra moisture in the inlet air increases drying cycle time
• Varying outside conditions result in inconsistent powder quality
• Higher downtime due to sticking of material on Spray Dryer walls