James L. Skinner

Method and apparatus for treating oil-water-solids sludges and refinery waste streams

Heavy hydrocarbon containing sludges such as refinery waste streams, oil storage tank sludges and marine oil tanker ballast are treated by passing the sludges in a flow stream through an indirect dryer to vaporize liquids having a boiling point at atmospheric pressure of less than about 700° C. and to provide substantially dried solid particles discharged from the dryer. The dried particles, containing heavy hydrocarbons as a coating or as a part of the solids, are conducted to a combuster/oxidizer and exposed to a high velocity flow stream of oxygen containing gas, typically low pressure forced air, to burn the residual hydrocarbons in the solids and to reduce heavy metals and the like to oxides thereof. A sludge handling system includes a rotary disk type indirect dryer connected to a lift pipe type combustor/oxidizer for thorough exposure of the dried solids to an oxygen containing atmosphere. A centrifigal or cyclone type gas-solids separator receives the flow stream discharged from the lift pipe and a portion of the dried solids may be diverted after discharge from the dryer back to the dryer inlet to reduce the moisture content of the sludge flow stream introduced to the dryer to minimize caking and clogging of the dryer itself.