An oven that heats from one side and vents from the other wastes most of its energy. The CT-C-II hot air circulation drying oven recirculates the majority of its hot air inside the chamber, so the same electrical or steam input dries twice the load of a once through oven, and the forced ventilation plus the adjustable air distributor keeps the temperature difference between the top and the bottom of the chamber within plus or minus 2 °C. For a 200 kg batch of granule on 96