- Direct dryers or adiabatic or contact type dryers, transfer heat by direct contact of the product with the hot gases.
- The gas transfers sensible heat to provide the heat of vaporization of the moisture present in the solid.
- It is possible to obtain some non-luminous radiation heat transfer benefit also in this case, since the moisture content in bagasse is quite high.
- Flue gas required for process is taken from the exhaust of the I.D. fans of the boiler or from a bagasse based special purpose furnace or boiler, and injected at the beginning of the dryer through a device for ensuring the safety of the system.