Exxon Research and Engineering Company

Walter S Kmak

Shun Chong Fung

David J Yates

Walter Weissman

James L Carter

Akira Yatabe

Charles Monzo

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.

Method of minimizing iron contamination during catalyst regeneration

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.

Reactivating iridium and selenium containing catalysts with hydrogen

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.

Reactivating iridium-containing catalysts with hydrogen halide and oxygen

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.

Reactivation of iridium-containing catalysts by halide pretreat and

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.

Method for removing coronene from heat exchangers

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.

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.

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.

Process for reactivating an iridium-containing catalyst

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.

Regeneration procedure

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., said gas being introduced into said reaction zone at a rate such that the halogen concentration of the treating gas at the outlet of said reaction zone is at least 50% of the inlet halogen 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 the treated catalyst in a reaction zone with hydrogen at an elevated temperature to reduce a substantial portion of the iridium present in the catalyst to its metallic form, and (5) contacting the catalyst from step (4) in a reaction zone with an elemental halogen-containing gas at a temperature of at least about 850.degree.F. Steps (4) and (5) may be repeated, in sequence, at least one additional time to redisperse the iridium catalyst component to a highly active, high surface area state.

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.

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Scotch Plains, NJ, United States of America

Walter S Kmak