PETKUS develops “green” dryer
Aug. 1, 2014
by World Grain Staff
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WUTHA-FARNRODA, GERMANY — PETKUS Technologie GmbH has developed the first dryer that can be operated entirely without fossil fuels.
A customer and owner of a biogas plant had requested a dryer whose heating system could be operated by hot water from his biogas plant. Since hot water is a by-product of the facility, the customer wanted to put it to use while saving on fossil fuel costs.
PEKTUS engineers, in cooperation with engineers from its partner Bednar FMT, created a continuous flow dryer on the basis of a car radiator, but the air is not cooled down but heated up and blown directly into the sections of the dryer house.
In the new PETKUS dryer, the external air is sucked through the hot water register that has a capacity of 800 kW basic heating. There it is heated up to 90 degrees C. This is the maximum and constant temperature that can be reached with this technique.
Whereas rape seed and most other seeds dry at a heating temperature of 70 to 80 degrees C – this does not apply to wheat and corn/maize. Here you need a temperature of either 95 degrees C or 130 degrees C. In order to reach this level of heat an extra infinitely variable electrical heating exchanger with a heating capacity of additional 500 kW needs to be installed.
In this way an optimal temperature can be reached in 10x50kW steps. The heating process is controlled by PLC system to get the right heating temperature. Keeping this in mind, the capacity of this progressive dryer is: nominal 220 tonnes per day (in wheat drying from 19% to 15% moisture).
This continuous flow dryer is a roof duct dryer made of a stable, galvanized steel plate construction for the most-efficient operation. The kernels will be dried effectively, gentle and economically. Due to the current overproduction of electricity in Czech Republic, the government supports financially each kWh which is not fed back in the energy grid.
The new plant was officially put into operation on June 6. About 250 guests were invited and followed the opening ceremony. Besides the official part with its speeches, interested guests could take part in a site tour through the new plant.