초록 ▼

This invention relates to improvements in a process for treating a catalyst, or bed of catalyst, comprised of a composite of an iridium metal or admixture of said metal with other metals, particularly platinum, or admixtures of iridium and platinum with other metals, halogen, and a refractory porous

This invention relates to improvements in a process for treating a catalyst, or bed of catalyst, comprised of a composite of an iridium metal or admixture of said metal with other metals, particularly platinum, or admixtures of iridium and platinum with other metals, halogen, and a refractory porous inorganic oxide, notably alumina which has been deactivated by coke deposition thereon, as commonly occurs in a hydroconversion reactions, notably as in upgrading virgin or cracked naphthas in catalytic reforming to produce higher octane products. The time required for reactivation of such catalyst can be shortened by deliberate agglomeration of the iridium, or admixture of iridium and other metal hydrogenation-dehydrogenation components, above about seventy percent, and preferably by essentially complete agglomeration of the iridium, or admixture of iridium and other metal hydrogenation-dehydrogenation components, prior to one or more cycles of sequential reduction/halogenation treatments. The desired high agglomeration of the iridium, or admixture of iridium and other metal hydrogenation-dehydrogenation components, is preferably accomplished by a relatively severe coke burn which not only achieves the desired agglomeration, but also more efficiently and effectively removes the coke from the coked catalyst.

대표청구항 ▼

In a process for the catalytic conversion of hydrocarbons wherein a hydrocarbon feedstock is contacted with a catalyst comprising an atomically dispersed iridium component composited with a refractory porous inorganic oxide support at conversion conditions, the catalyst having been at least partiall

In a process for the catalytic conversion of hydrocarbons wherein a hydrocarbon feedstock is contacted with a catalyst comprising an atomically dispersed iridium component composited with a refractory porous inorganic oxide support at conversion conditions, the catalyst having been at least partially deactivated during contact with said feedstock by the deposition of coke deposits thereon, and thereafter the bed of said catalyst is contacted with a gaseous mixture containing oxygen at an elevated temperature for a time sufficient to burn a substantial portion of said coke deposits therefrom, the iridium component having been agglomerated, and the iridium component then redispersed upon the support by treatment in one or more cycles of sequential reduction/halogenation steps, the reduction step being characterized as one wherein the agglomerated catalyst is contacted with reducing gas at an elevated temperature for a time sufficient to reduce a substantial portion of said iridium on said catalyst to its metallic form, and the redispersion step as one wherein the reduced catalyst, which has a substantial portion of the iridium contained thereon in metallic form, is then contacted with a halogen-containing gas at a temperature of at least about 300°C., the improvement comprising burning the coke off the deactivated catalyst by contact with the oxygen-containing gaseous mixture at temperature and time sufficient to agglomerate above seventy weight percent of the iridium to relatively large crystals whose sides (length of a side of an assumed cubic crystallite) are greater than about 50 Angstrom units, as measured by x-ray or chemisorption techniques, prior to said treatment of said coke depleted catalyst in one or more cycles of sequential reduction/halogenation steps.