Equipment Process Description
Normally the material is transferred to the receiving hopper of the feed system using a front-end loader or crane. An inclined conveyor takes the material from the hopper and transfers the feed to the ATDU through a double tipping valve assembly. Material to be furnished to the ATDU is to be all two- (2) inch minus (5 cm).
The ATDU is an indirectly heated rotary drum, which is operated in a parallel flow configuration. The burner flame and exhaust gases do not come into contact with the contaminated material. The drum rotates within an insulated chamber, which can be heated by combination fuel burners capable of burning natural gas, fuel oil, syngas, or propane. As the drum rotates, the surface of the contaminated material exposed to the metal surface is continuously renewed which facilitates the transfer of heat from the heated chamber through the drum to the material. The material is heated to a sufficient temperature to volatilize the contaminants. This is achieved under anaerobic conditions thereby preventing oxidation of the hydrocarbons or chemical compound.
The processed solid material is discharged from the ATDU through a double tipping valve to a pugmill mixer-cooler (standard) where water is injected and mixed for direct contact material cooling. Optional jacketed screw conveyors are available for indirect cooling. With either option the hot discharged material from ATDU is cooled using either direct or indirect contact with water. After exiting the ATDU all process gases undergo a recovery/condensation and cooling process in the Vapor Recovery Unit (VRU). The condensables are processed in the Oil Water Separator (OWS) which is an integral part of the primary Water Treatment Unit (WTU). The recovered water and sludge from the WTU are stored in tanks or roll offs as required by operator.