Feed system for incineration of contaminated material

Abstract

A method for incinerating contaminated soil or other material utilizing an incinerator, such as a CBC, which is operated below atmospheric pressure and apparatus for carrying out such decontamination by delivering the soil to be processed in desired particulate size to the incineration unit, e.g., to a recirculation loop through which separated solids are being returned from a cyclone to a CBC. The system for supplying the contaminated soil is isolated from the chute leading to the incineration unit by a feeder that forms an agglomerated plug which serves as a pressure seal and prevents any gas flow therepast. Illustrated are a pair of twin counterrotating screws which include shafts that extend past the ends of the screw flights to locations where rotary cutters having multiple blades are mounted. Soil being carried between the flights of the rotating screws continuously agglomerates to form a plug at the downstream end which continuously advances toward the cutter blades that slice it into chips of desired thickness, which then pass through all or a portion of a pug-mill before entering a chute leading to the incinerator. The screws and rotary cutters are advantageously mounted on common shafts so as to allow longitudinal adjustment of the distance between the cutter and the screw to vary the length of the plug.