TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The sorted materials are reduced to a uniform, hard granular solid fuel product by means of in situ heating and mixing caused by the reactor. The pyrolysis is conducted at 500-600 degrees F. In the process, byproduct water vapor, oils and gases are removed from the pyrolysis reactor by separate vents. The byproduct water vapor produced in a first mixing/drying zone of the reactor is used to remove any entrapped air from the sorted materials by way of a first gas vent, thus reduces dioxin formation potential in subsequent pyrolysis zones in the reactor. The byproduct oils, gases and sensible heat are utilized in a boiler to produce steam. Preferred Components: The sorted material is both dried and pyrolyzed within a single reactor. The pyrolysis is conducted in a twin screw mixer, converting the mechanical shaft energy of mixing using viscous shear forces to produce in-situ heating of the sorted materials. EXAMPLE - 2000 pounds Of urban waste were sorted to remove foreign material and shredded to produce 1500 pounds of organic matter equivalent to refuse derived fuel. The shredded waste material was fed by metered conveyor to the feed port of the pyrolysis reactor, where it was conveyed and compacted by the internal reactor augers, which deliver it to the first mixing zone. Intense mixing converts mechanical work into direct in situ heating of the waste materials through viscous shear forces within the feedstock itself. During the short period in which the waste was maintained within the first mixing zone, the temperature of the waste was increased to 260 degrees F, liberating moisture in the form of water vapor. The waste leaves the mixing zone, passing into an area without compaction, which permits the vapors and solids to separate, with the water vapor leaving the reactor from a vent on its top surface, at 260 degrees F. Any air or free oxygen that may have been entrained in the feedstock during compaction was carried away by the vented water vapor, to ensure that it was not available during the subsequent pyrolysis stages of the process. The waste was again compacted, and transported to the first of two pyrolysis zones. Again intense mixing by paddle elements of the augers converts mechanical work into in situ viscous heating, raising the temperature of waste to 500 degrees F. After 30 seconds, the partially pyrolyzed waste has passed through the second mixing zone, after which it again enters a zone without compaction. Here pyrolysis byproduct oils, gases and chlorine were liberated from the solids and leave the reactor through a vent port on the top. Third stage compaction and mixing occurs, the temperature of waste material raised t0 500-600 degrees F, more fully pyrolyzing the waste materials. After 30 seconds of in situ heating and pyrolysis, the material passes to a final uncompacted degassing zone, in which byproduct oils, vapors and chlorine were liberated. Vent port on the top of the reactor allows for the removal of these byproduct materials. The remaining solids were conveyed to the discharge end of the mixing reactor, where they were then delivered to an enclosed contact cooler, consisting of a water cooled conveying screw. The cooling system reduces the temperature of the synthetic coal (char) product in an oxygen-free environment, without direct contact with process water, stopping the pyrolysis reaction, and preventing any post pyrolysis dioxin formation. Heat recovered from the cooling system was utilized for boiler feedwater heating.