REMOVAL OF CONTAMINANTS FROM SPENT HYDROPROCESSING CATALYSTS THROUGH CONTINUOUS SOLVENT EXTRACTION AND BATCH CLOSED VESSEL SOLVENT EXTRACTION

摘要

The present invention provides a continuous process for removing contaminants, comprising oil, coke and iron sulfide deposits, from a spent hydrotreating or hydropocessing catalyst obtained from reactors and recovering the decontaminated catalyst. The oil is removed by a continuous solvent extraction process (20) using one or more screw conveyors (24). Through a stripping process, any residual solvents may be removed. In a continuous process, the stripping process may be performed by a stripping screw conveyor, or by a screw conveyor in the solvent extraction process having stripping capability. The solvent may be stripped from the catalyst by hot gas stripping, using an inert gas. The solvent is most preferably circulated in a closed vessel from bottom to top for approximately four hours at approximately 1.5 Liquid Hourly Space Velocity (LHSV). The oil-free solvent-free catalyst is subsequently decoked through a controlled oxidation process by a decoker (50). The oil-free solvent-free catalyst is transferred to a catalyst storage (80) with an inert gas blanket.