Process for reactivation of iridium-containing catalysts

Abstract

A process for reactivating a catalyst comprising iridium, or iridium as a component of a multimetallic combination, particularly one which includes both iridium and platinum admixed one with the other, and with other metal components, and halogen, composited with a refractory porous inorganic oxide, previously inactivated by coke deposition thereon, possible loss of halogen content and agglomeration of the metal, or metals, or oxides thereof, such as occurs in a reforming process wherein such catalyst is contacted with a hydrocarbon feed at reforming conditions, and subsequently regenerated by burning accumulated coke deposits therefrom. A bed of the coke-depleted catalyst, wherein up to about 70 weight percent of the iridium of the catalyst is present as agglomerates of crystallite sizes greater than about 50A, is contacted in a plurality of cycles, an initial cycle of which includes, in sequence, (i) reduction of the coke-depleted catalyst, as by contact thereof with a stream of reducing gas, e.g., hydrogen or hydrogen-containing gas, at temperature sufficient to reduce the said iridium component, or the iridium component in admixture with other components, and (ii) contact of the reduced catalyst, up to or not significantly beyond the time of halogen breakthrough, with a halogen, or halogen precursor, in the presence of insignificant concentrations of added molecular oxygen, if any, at temperature sufficient to redisperse the agglomerates, and subsequent cycles of which include, in sequence, reduction as defined in step (i), supra, and halogenation as defined in step (ii), supra, whether or not molecular oxygen is added.