Process for pasteurising sludge, in particular sewage sludge, and pasteurisation vessel for carrying out the process

摘要

This pasteurisation process is intended to operate continuously and at the same time to preclude re-infections. In the cylindrical, heat-insulated pasteurising vessel (1) ascending slightly towards the sludge outlet end, a single-flight conveyor screw (2) rotates which continuously and positively advances the sludge towards the vessel outlet end. The vessel (1) is filled with sludge only to such a level that the screw rotor shaft (3) is not flooded by the sludge. In this way, the helical parts of the screw flight (13) immersed in the sludge, always keep individual sludge portions (S) in the vessel (1) separate from one another. Correspondingly, mutually separate gas spaces (G) are formed in the upper vessel part by helical screw sections protruding from the sludge (s). Vent pipe branches (14) connect these gas spaces (G) to a gas header (15) through which the gases escaping from the sludge (S) are discharged into the open. This gas header (15) has a downward gradient towards the vessel outlet end, and the vent pipe branches (14) protrude upwards beyond the inner wall of the gas header (15). This avoids back-flow of the condensate formed in the header (15) into the pasteurising vessel (1). The lower horizontal edge (18) of the sludge outlet opening (17) of the vessel (1) is located no lower than the height of the sludge level (N), in order to maintain the latter. <IMAGE>