Patent ID: 7820579

Claim:
A method of restoring the activity of a spent non-additive based hydroprocessing catalyst comprising a catalytically active metal component and a support, said method comprising: Contacting with a solution said spent non-additive based hydroprocessing catalyst having a reduced catalytic activity relative to a non-additive based hydroprocessing catalyst in its fresh state prior to use thereof to thereby become said spent non-additive based hydroprocessing catalyst, wherein said solution comprises a solvent and a chelating agent capable of forming a complex with said catalytically active metal component of said spent non-additive based hydroprocessing catalyst, and wherein said contacting is done for a time period from about 10 hours to about 900 hours during which time period said chelating agent reacts with and re-disperses said catalytically active metal component thereby resulting in an aged catalyst having incorporated therein said chelating agent and said solvent and a re-dispersed catalytically active metal component; Exposing said aged catalyst to conditions including a drying temperature less than 250° C. so as to remove from said aged catalyst a portion of said solvent without removing more than 50 weight percent of said chelating agent from said aged catalyst thereby resulting in a dried aged catalyst; and Sulfur treating said dried aged catalyst without prior exposure to a calcination temperature exceeding 400° C., to yield a restored hydroprocessing catalyst.