Abstract: An improved apparatus and method for the continuous processing of organic carbonaceous materials containing appreciable amounts of water to produce thermally upgraded products suitable for use as fuels, carbon-containing chemical intermediates, and the like. The apparatus and process utilizes controlled elevated temperatures and pressures to which the feed material is sequentially subjected including a preheating stage, a pressurized dewatering stage and a reaction stage during which vaporization of at least a portion of the volatile organic and moisture constituents therein is effected to form a gaseous phase. The intervening dewatering stage removes a large proportion of the initial moisture content of the feed material whereby substantially improved efficiency and increased capacity are attained.