SERA is a pioneer in introducing this technology in France, the tubed screw is particularly suitable for storage silos of 2500 m3 without volume limit. The operating cost is the lowest of all technologies currently known with consumption 70% lower than the conventional extracting screw systems or hydraulic ladders.
Its low power consumption is directly related to low mechanical strengths that will proportionally reduce the equipment wear.
The extraction has all the advantages of extraction screws at the bottom of silo (FIFO, direct access to stock, simple maintenance access) while allowing the biomass homogenization and reducing the engineering impact. Unlike conventional extraction screws, uncased, the tubed screw causes no load on structures. The screw, protected by the tube becomes a simple handling augers and does not have to bear the stock load.
Despite appearances, this system perfectly meets the needs of a poorly calibrated material. The references show that this technology supports a heterogeneous biomass with a significant particle size.
The biomass is brought into the silo from above, this naturally creates different product layers according to deliveries (dry wood, wet wood, wood chips, screening waste, pallet waste class A, various wood species, etc.). With the tubed screws, these layers are mixed thus giving to the fuel a better consistency, both at the PCI level as moisture. This will allow better combustion stability during operating and therefore a better control of air emissions, particularly NOx management.
