Waste pyrolysis using superheated steam - with uniform controlled heat input and waste heat recovery

摘要

A waste pyrolysis process is carried out by directly contacting the waste with superheated steam which causes mixing, comminution and vol. redn. of the waste in a heating chamber, the resulting pyrolysed prod. being pressure impregnated with superheated steam in a cylinder and then autogenously compacted and briquetted by pistons by means of the vacuum effect of cooling the cylinder outer wall. The steam may be previously used or directly produced steam and is superheated by counter-current heating, its waste heat content subsequently being used for steam prodn. Also claimed is appts. for carrying out the process. Pref. the heating chamber contains a conveyor screw with an axial conical passage enclosing a rotor shaft and a cutting blade rotor mounted on the rotor shaft. An inner cylinder is located within and spaced from the cylinder and has bottom openings or perforations, a piston being moveable within the inner cylinder and having an outwardly extending piston rod. ADVANTAGE - The process has low heat losses and provides uniformly distributed direct heat input, precise maintenance of the preset pyrolysis temp. and max. utilisation of waste heat.