NOVELTY - Twin-screw extruder (1) for thermomechanical digestion of organic raw materials and residues, comprises an elongated extruder housing (2) and two counter rotating screw extruders arranged parallel to each other. The elongated extruder housing exhibits a lower housing part (3) with U-shaped cross section on the inner side, with upward shell opening (4). The extruders are mounted only at a first end on the rear end plate of the elongated extruder housing and respectively exhibit a not mounted, free end module at the opposite second end.    USE - The twin-screw extruder is useful for thermomechanical digestion of organic raw materials and residues, preferably a biomass for the production of biogas (claimed). The extruder is also useful for the food processing and food mixture in animal husbandry and for splitting of pulses for the vegetable oil extraction.    ADVANTAGE - The lifetime of wear parts of the extruder is increased compared to previous systems. The mechanical efficiency of the extruder to digest the biomass is improved, thus the surface of the biogenic material can also be increased, so the gas yield through the anaerobic fermentation of biomass is increased compared to other systems. The residence time of biomass in the fermenter and the energy consumption are also reduced.    DETAILED DESCRIPTION - Twin-screw extruder (1) for thermomechanical digestion of organic raw materials and residues, comprises an elongated extruder housing (2) and two counter rotating screw extruders arranged parallel to each other. The elongated extruder housing exhibits a lower housing part (3) with U-shaped cross section on the inner side, with upward shell opening (4), which extends horizontally between a rear end plate (6) and a front face plate. The lower housing part forms a hollow cylindrical guide section in a closed state along with a cover, which on the inner side exhibits an inverted U-cup-shaped cross section with downward opening (9), by superimposing the opening of the housing part and the opening of the housing cover, where the guide section rests at the front of the end plate. The extruders (both of which are self-supported) are mounted only at a first end on the rear end plate of the elongated extruder housing and respectively exhibit a not mounted, free end module at the opposite second end, where the extruder screws are wrapped in the closed position at least partially by the hollow cylindrical guide section from the lower housing part and the housing cover. The lower housing part and the housing cover on their inner sides are respectively provided with wear inserts. The wear insert of the lower housing part exhibits a U-shaped cross section with upward curved side walls, which form the U-lower support in the U-shaped cross-section and are bent outward horizontally at their upper ends to the opening respectively under the formation of flanges. The wear liner of the housing cover exhibits inverted U-shaped cross section with two downwardly curved side walls, in a closed state. The downwardly curved side walls form the U-lower support in the U-shaped cross-section and are bent outward horizontally at their lower ends under the formation of flanges. In a closed state, when superimposing the openings, the two outwardly bent flanges of the lower housing part and the folded outward flanges of the housing cover casing (8) are contacted with one another. The extruder screws respectively exhibit a screw pitch, which becomes smaller from the first end to beginning of the free end module, where the free end module has an opposite screw pitch. INDEPENDENT CLAIMS are also included for:    (1) a device for thermomechanical digestion of organic raw materials and residues, comprising a sub-frame, a drive module that is mounted on the sub-frame, with two engines and two transmitting cardan shaft for power transmission and two cardan shaft connected with the extruder axis, the twin screw extruder, which is arranged on the sub-frame behind the drive module, where the extruder screw of the twin screw extruder are driven by the drive module, and the sub-frame, on which the twin-screw extruder is attached, exhibits access doors for maintenance below the twin screw extruder; and    (2) thermomechanical digestion of organic raw materials and residues, comprising supplying the material to be digested to the double screw extruder, in which the material is passed through an extrusion process.    DESCRIPTION OF DRAWING(S) - The figure shows a perspective representation of the twin-screw extruder.    Twin-screw extruder (1)    Elongated extruder housing (2)    Housing part (3)    Upward opening (4)    Rear end plate (6)