Proposed over 100 years ago; received serious attention
only during the past 20-30 years
• Uses superheated steam instead of hot air or
combustion/flue gases in a direct (convection) dryer
• More complex equipment than hot-air drying system;leakproofing
needed; feed/discharge can be difficult
• Lower net energy consumption (if exhausted steam can
be used elsewhere in the process and not charged to
dryer)
• Better product quality (in most cases);Safe operation, no
fire/explosion hazard; no oxidation