Abstract: The present invention is directed toward improved processes for the regeneration of noble metal-containing catalysts wherein iron contamination of the catalyst during regeneration is significantly diminished. It has been found that maintenance of any iron present in contact with the catalyst in the oxidized state (e.g., as Fe.sub.2 O.sub.3 or Fe.sub.3 O.sub.4) during contact of the catalyst with a source of halogen in the regeneration haliding step results in a marked decrease in the degree of catalyst contamination by iron species.

Abstract: The present invention is directed toward improved processes for the regeneration of noble metal-containing catalysts wherein iron contamination of the catalyst during regeneration is significantly diminished. It has been found that maintenance of any iron present in contact with the catalyst in the oxidized state (e.g., as Fe.sub.2 O.sub.3 or Fe.sub.3 O.sub.4) during contact of the catalyst with a source of halogen in the regeneration haliding step results in a marked decrease in the degree of catalyst contamination by iron species.

Abstract: A process is disclosed for reactivating an agglomerated iridium and selenium containing catalyst and particularly platinum-iridium-selenium on alumina reforming catalysts. The process includes contacting a substantially decoked agglomerated catalyst with a reducing gas such as hydrogen to reduce agglomerated iridium oxides present to the free metal, a hydrogen halide pretreatment step to increase the halogen level of the catalyst to about 1.3 weight percent and above, and a redispersion step involving hydrogen halide and elemental oxygen. Use of hydrogen halide and elemental oxygen in the redispersion treatment eliminates the need for use of elemental chlorine gas. If no iridium oxides are initially present, the hydrogen reduction step is optional.

Abstract: A process is disclosed for reactivating an agglomerated iridium-containing catalyst and particularly a platinum-iridium on alumina reforming catalyst. The process includes contacting an agglomerated catalyst with a reducing gas such as hydrogen to reduce agglomerated iridium oxides to the free metal, a hydrogen chloride pretreatment step to increase the chloride level of the catalyst to about 1.6 weight percent and above, and a redispersion step involving contacting with elemental oxygen. The process eliminates the need for gaseous chlorine in the redispersion feedstream. If no iridium oxides are initially present, the hydrogen reduction step is optional.

Abstract: A process is disclosed for reactivating an agglomerated iridium-containing catalyst and particularly platinum-iridium on alumina reforming catalysts. The process includes contacting a substantially decoked agglomerated catalyst with a reducing gas such as hydrogen to reduce agglomerated iridium oxides present to the free metal, a hydrogen halide pretreatment step to increase the halogen level of the catalyst to about 1.3 weight percent and above, and a redispersion step involving hydrogen halide and elemental oxygen. Use of hydrogen halide and elemental oxygen in the redispersion treatment eliminates the need for use of elemental chlorine gas. If no iridium oxides are initially present, the hydrogen reduction step is optional.

Abstract: Coronene deposits are removed from a heat exchange zone of the reforming process by recycling a portion of the normally liquid reformate to the heat exchange zone to dissolve the coronene deposits.

Abstract: Coronene deposits are removed from a heat exchange zone disposed in two parallel trains of heat exchangers in a reforming process by reducing the flow of reforming zone effluent in one of the trains of heat exchangers sufficiently to effect condensation of a portion of the reforming zone effluent in said one train of heat exchangers where the coronene is deposited while simultaneously increasing the flow of reforming zone effluent in the second train of heat exchangers. Control means are provided in each of the heat exchange trains.

Abstract: Coronene deposits are removed from a heat exchange zone of a reforming process by operating the reforming zone at conditions such that at least a portion of the reformer effluent condenses in the heat exchange zone where the coronene deposit occurs.

Abstract: 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.

Abstract: Supported iridium-containing hydrocarbon conversion catalysts which are at least partially deactivated due to the deposition of carbonaceous residues thereon during contact with hydrocarbons are regenerated by (1) contacting the catalyst with oxygen to burn at least a portion of the carbonaceous residues from the catalyst, (2) contacting the carbonaceous residue-depleted catalyst with an elemental halogen-containing gas at a temperature of less than about 850.degree.F., (3) contacting the treated catalyst with hydrogen at elevated temperatures to reduce a substantial portion of the iridium present in the catalyst to its metallic form, and (4) contacting the catalyst from step (3) with an elemental halogen-containing gas at a temperature of at least about 850.degree.F. Steps (3) and (4) may be repeated, in sequence, at least one additional time to redisperse the iridium catalyst component to a highly active, high surface area state.

Abstract: Supported iridium-containing hydrocarbon conversion catalysts which are at least partially deactivated due to the deposition of carbonaceous residues thereon during contact with hydrocarbons are regenerated by (1) contacting the catalyst in a reaction zone with oxygen to burn at least a portion of the carbonaceous residues from the catalyst, (2) contacting the carbonaceous residuedepleted catalyst in a reaction zone with hydrogen at an elevated temperature to reduce a substantial portion of the iridium present on the catalyst to its metallic form, (3) contacting the treated catalyst in a reaction zone with an elemental halogen-containing gas in a reaction zone with an elemental halogen-containing gas at a temperature greater than about 850.degree.F.

Abstract: Supported iridium-containing hydrocarbon conversion catalysts which are at least partially deactivated due to the deposition of carbonaceous residues thereon during contact with hydrocarbons are regenerated by (1) contacting the catalyst with oxygen to burn at least a portion of the carbonaceous residues from the catalyst, (2) contacting the carbonaceous residue-depleted catalyst with hydrogen at an elevated temperature to convert a substantial portion of the iridium present in the catalyst to its metallic form, (3) contacting the reduced catalyst with an elemental halogen-containing gas at a temperature of at least about 300.degree.C., and (4) repeating steps (2) and (3), in sequence, at least one additional time to thereby redisperse the iridium catalyst component to a highly active, high surface area state.