Krann gasifiers can be used for both direct and indirect drying. The flue gases can
be used directly for most of the drying applications. Such an approach lowers the
capital cost of the application and is possible only because of the cleanliness of
the Krann flue gases. The clean flue gas is typically blended down with ambient air
before entering the dryer inlet. The flow of ambient air is controlled to maintain
the temperature at the required level for the drying.
For processes where only ambient air can be used, Krann provides a flue/air heat
exchanger. The heat exchanger is still more efficient than conventional burners due
to a reduction in dust deposits on the heat transfer surfaces.
Lumber drying kilns or various rotary dryers are examples of Krann drying applications.
Krann can provide the controls for all the heating equipment or incorporate the gasifier
control into the existing PLC. The user is then able to monitor and set the targets
of all important process parameters. The drying operation is fully automatic and
requires minimum supervision. At the dryer inlet, the program controls both the gasifier
heat output, the dryer inlet and output temperatures. Additionally, Krann offers
an optional automatic control of the end-product’s exit moisture. The moisture target
is set by the operator and the control system adjusts the gasifier/dryer parameters