Regeneration procedure

In a process for the catalytic reforming of a naphtha feed stock wherein said naphtha feed stock and hydrogen are contacted with a catalyst comprising from about 0.01 to about 3.0 wt. % of an iridium component and a halogen component contained on an alumina support at naphtha reforming conditions, the catalyst having been at least partially deactivated during contact with said naphtha feed stock by the deposition of carbonaceous residues, a method for regenerating said catalyst after discontinuing contact of said catalyst with said feed stock comprising;

• 1. contacting said catalyst in a reaction zone with a gaseous mixture containing oxygen at an elevated temperature for a time sufficient to burn a substantial portion of said carbonaceous residues from said catalyst, the duration of said contacting at said elevated temperature being insufficient to convert more than about 70 wt. % of the iridium on said catalyst to agglomerates having crystallite sizes greater than about 50A;
• 2. contacting said carbonaceous residue-depleted catalyst in said reaction zone with a gas mixture containing hydrogen at a temperature varying from about 650.degree. - 950.degree. F. for a time sufficient to convert a substantial portion of said iridium to its metallic form, wherein said step (2) is effected prior to contact with a substantially halogen-free, oxygen-containing gas at a temperature sufficient to agglomerate further the iridium on said catalyst;
• 3. contacting said treated catalyst having a substantial portion of the iridium contained thereon in the metallic form in said reaction zone with a gas mixture containing chlorine at a temperature of greater than about 850.degree. F., said gas mixture being introduced into said reaction zone at a rate such that the chlorine concentration of the treating gas at the outlet of said reaction zone is at least 50% of the inlet chlorine concentration within at least 15 minutes from the time of the introduction of said treating gas into the inlet of said reaction zone;
• 4. contacting said chlorine treated catalyst in a reaction zone with a gas mixture containing hydrogen at a temperature varying from about 650.degree. to 950.degree. F. for a time sufficient to convert a substantial portion of said iridium to its metallic form;
• 5. contacting said treated catalyst having a substantial portion of the iridium contained thereon in the metallic form in said reaction zone with a gas mixture containing chlorine at a temperature greater than about 850.degree. F. for a time sufficient to redisperse at least a portion of the iridium on the catalyst;
• and
• 6. contacting said treated catalyst from step (5) in a reaction zone with said naphtha feed stock and hydrogen at naphtha reforming conditions, wherein said step is effected prior to contact with a substantially halogen-free, oxygen-containing gas at a temperature sufficient to agglomerate the iridium on said catalyst.