The Study of a Deposit Prevention System on a Drying Chamber Wall in Spray Drying Process

A spray drying chamber with an air barrier system has been developed for the purpose of the deposit-free operation of the spray drying of a Kampo (chinese herb) extract. The preventive effect of the air barrier system on depositon on the chamber wall during spray drying operations was studied in comparison with a hammer and air-broom system using a liquid with 20% solid which is adhesive to the chamber wall.The amount deposited on the test plates placed on the chamber wall using the air barrier system was smaller than the other preventive systems, hammer and air-broom. The recovery of solids by spray drying using a drying chamber with the air barrier system was 65%. On the other hand, the recovery of solids using the drying chamber with hammer and air-broom was 31% and 39%, respectively, under operating conditions.These results showed that the spray drying chamber with an air barrier system was the most effective method of the other preventive systems for the prevention of deposition on the chamber wall.