In September this year Van Beek will again supply extraction screw conveyors for removing fermentation waste from a DRANCO fermentation tank to OWS from Ghent (Belgium). This time the installation will be used in Leszno (Poland).
OWS (Organic Waste Systems) is world leader in the engineering and operation of biogas installations for solid and semi-solid organic substrates and provides advice on waste management. The DRANCO process they have developed is one of the most efficient and proven technologies for anaerobic digestion of household waste.
The name DRANCO stands for DRy ANaerobic COmposting and is a waste processing process in which dry digestion is used as the central operating step to convert the organic fraction from household waste to compost. The biogas produced is used to generate electricity, heat or steam.
The extraction screw conveyors designed by Van Beek are located underneath the fermentation tank and remove the fermented out mass. There are no moving, mechanical components in the fermentation tank itself. The fermenting mass is too semi-solid for this and moves downwards only by gravity, depending on the rate at which the fermented out residue is extracted from underneath the digester (fermentation tank) by the screw conveyors.
The biogas that develops in the digester rises spontaneously through the pores and is transferred via gas pipes in the roof to the biogas processing plant. After 48 to 72 hours the fermenting material reaches the conical outlet of the fermentation tank where it is removed using tubular conveyors in a cascade setup. This has a capacity of 40 m³/hour to 100 m³/hour depending on the size of the fermentation tank.
A fermentation tank has a volume of 500 m³ to 3500 m³ depending on the capacity of the installation. A heavy-duty design of extraction conveyor is as a result necessary to be able to withstand the high pressure of the mass in the tank. The stainless steel tubular conveyors are designed with heavy-duty gaskets, flanges and stainless steel packing boxes and can withstand a pressure of 3 to 5 Bar.
For over 13 years already Van Beek has been designing and producing screw conveyors for OWS for a variety of projects. For the successful DRANCO process which is still under development Van Beek has already been able to supply installations for various plants in Spain, Germany, France, Italy and Belgium.