Process and apparatus for the conversion of sludges

Abstract

There is disclosed a new process for the conversion of the organic components of sludge, particularly sewage sludge, to produce useful, storable, energy-containing oil products, apparatus for carrying out the process and a control process for optimization of the process temperature. The sludge preferably is mechanically dewatered to about 20-25% solids by weight and thermally dried to about 90% solids by weight. The resultant material is comminuted and heated in the apparatus of the invention to at least 250.degree. C. in a heating zone in the absence of oxygen to generate a gaseous atmophere containing volatiles; this atmosphere is then removed, scrubbed of H.sub.2 S and NH.sub.3 if required, and passed preferably in countercurrent flow in a heated reaction zone in intimate contact with the "devolatilized" sludge solids from the heating zone, again in the absence of oxygen, at a temperature of at least 280.degree. C., resulting in catalyzed vapor phase oil-producing reactions. The oil vapors are carried out by the gas flow and condensed. The preferred apparatus moves the sludge solids cocurrent with the heating zone atmosphere and countercurrent with the reaction zone atmosphere. In the reaction zone the conveyor not only moves the comminuted sludge along but lifts it and drops it through the gaseous atmosphere of the preferred intimate contact. Preferably the sludge is examined repeatedly by differential scanning calorimetry to generate a thermogram which has been found to reveal immediately the optimum temperature for operation of the reaction zone, and also the anticipated oil yield from the sludge.

Dependencies are inferred from the claim text.