Abstract: A solid catalyst composition which has undergone a partial loss of catalytic activity due to the accumulation of reaction product residue is treated in a chemical conversion process reaction zone in the presence of feedstock(s) with ultrasonic energy of a magnitude and a duration sufficient to restore at least a significant percentage of the lost activity.

Abstract: Method and apparatus for effecting treatment needed to regenerate spent hydrocarbon conversion catalyst. The invention may be termed a variable gas flow catalyst bed. Catalyst particles in a vertically-elongated movable bed are contacted with a hot oxygen-containing gas stream in order to remove, by means of combustion, coke which accumulated on the catalyst particles while they were used in a hydrocarbon conversion zone. The catalyst particles are confined in the bed by means of catalyst retention screens. The catalyst retention screens are configured such that gas flow through the bed varies from a maximum at the top of the bed to a minimum at the bottom of the bed. The variation in gas flow is accomplished by varying the size of gas flow apertures in the retention screens from a maximum at the top of the bed to a minimum at the bottom of the bed.

Abstract: Supported iridium-containing hydrocarbon conversion catalyst that are at least partially deactivated due to the deposition of carbonaceous residues thereon during contact with hydrocarbons are reactivated by (1) contacting the catalyst with a gas containing oxygen and a chlorinated compound at a temperature not exceeding about 425.degree. C. to burn a major portion of the carbonaceous residues from the catalyst, (2) contacting the partially carbonaceous residue depleted catalyst with a gas containing a chlorinated compound a temperature of at least about 460.degree. C. to increase the chloride content thereof, (3) contacting the chlorinated catalyst with a gas containing oxygen and a chlorinated compound at a temperature of at least about 460.degree. C.

Abstract: A method for regenerating coke-contaminated catalyst particles achieves better utilization of oxygen and minimizes surface area loss of the catalyst by confining particles in the combustion section of a regeneration zone to a tapered bed configuration. In this method, catalyst particles move through the regeneration zone in continuous or semi-continuous flow and are formed into a vertically elongated bed of particles in the regeneration zone. An oxygen-containing gas is passed through the particle bed in a transverse direction and initiates combustion of the coke deposits along a burn front that extends diagonally through the catalyst bed from the inlet surface of the bed to the outlet surface of the bed.

Abstract: The present invention is a process for regenerating a large-pore zeolitic catalyst that has been deactivated by the formation of Group VIII metal agglomerates on the catalyst surface. In the process, the Group VIII metal agglomerates are redispersed to produce agglomerates of small size. It comprises an oxychlorination step, a nitrogen purge step and a reduction step.

Abstract: The present invention is a process for regenerating a sulfur-contaminated, highly selective, large-pore zeolite catalyst. It comprises a multistep process involving exposure of the catalyst to a combination of oxidizing conditions, reducing conditions and treatment with a halogen acid gas. These conditions are effective to agglomerate a Group VIII metal and remove sulfur. Thereafter, the catalyst is oxychlorinated to redisperse the Group VIII metal over the catalyst surface. A carbon removal step is optionally included.

Abstract: A process for dispersing or redispersing relatively large crystallites of an agglomerated Group VIII noble metal species present on a porous inorganic support is disclosed. The process includes contacting the agglomerated noble metal species, e.g., palladium or platinum, present on the support, e.g., alumina, silica or a zeolite such as ZSM-5 from which at least a major portion of any extraneous matter such as coke or other residue has previously been removed, with nitric oxide (NO) alone or in admixture with a source of halogen such as Cl.sub.2 and thereafter removing sorbed nitrogen oxide(s). The thus treated metal-loaded catalyst demonstrates substantially increased benzene hydrogenation activity (BHA) compared to the same catalyst prior to treatment indicating significant dispersion/redispersion of the metal crystallities as smaller crystallities.

Abstract: The invention concerns a process for regenerating a hydrocarbon hydroconversion catalyst containing a carrier, at least one group VIII noble metal and a halogen or halogenated compound.It is characterized by an operation in two regeneration zones (1) and (2). The gas effluent from the first regeneration zone (1) is used to feed the second regeneration zone. During the step of burning coke deposited onto the catalyst in the first zone, the heat amount generated during the combustion is used for preheating the feed of said first zone. The temperature of the effluent of said first zone is reduced, through said exchanger, to a value adapted to perform the burning step in the second zone. Additional air is supplied before introducing the gas into said second zone (2) in order to obtain a suitable oxygen concentration.

Abstract: A vessel for effecting multiple treatment steps needed to regenerate spent hydrocarbon conversion catalyst. Regeneration is accomplished in a moving bed of catalyst, where catalyst is passed through several treatment zones in the regeneration vessel. Catalyst is contacted with a hot oxygen-containing gas stream in order to remove coke which accumulates on the catalyst while it is in a hydrocarbon conversion zone. After the coke is burned off in a combustion zone, catalyst is passed into a drying zone for removal of water formed in the combustion zone which has remained on the catalyst instead of being carried off with combustion gases. Water removal is accomplished by passing a hot dry air stream through the catalyst. This air stream is introduced into the bottom of the regeneration vessel and is heated by exchange of heat with catalyst, thereby effecting the required cooling of the catalyst. Before passing into the drying zone, the air is heated further by heating element located in the vessel.

Abstract: A method for reactivating noble metal-containing zeolites containing sulfur oxide poisoned noble metal such as oxygen regenerated platinum zeolite beta catalysts, by contacting the catalyst with an acidic aqueous solution having a pH below about 7. The solution contains a Bronsted acid compound having a dissociation constant ranging from about 1.times.10.sup.-14 to about 2.times.10.sup.-1.

Abstract: A method is described for the regeneration of a hydrocarbon conversion catalyst that has become deactivated by carbonaceous material deposition where the catalyst comprises a nonacid zeolite and a Group VIII metal component. The method comprises the steps of (1) removing a substantial portion of the carbonaceous material from the catalyst by combustion with an oxygen-containing gas in the presence of a halogen, and (2) reducing the catalyst in the presence of hydrogen.

Abstract: A hydrocarbon conversion process is disclosed which extends the useful life of a regenerable zeolite-containing hydrocarbon conversion catalyst. In one aspect of this process, a hydrocarbon feed containing fluorides is passed through a fluoride removal system which reduces the fluoride concentration of the feed to below 100 ppb. The hydrocarbon feed containing less than 100 ppb fluorine is then converted over a regenerable zeolite-containing hydrocarbon conversion catalyst. The zeolite-containing hydrocarbon conversion catalyst is regenerated with an oxygen-containing gas stream as necessary to burn off carbonaceous deposits on the catalyst so as to return the zeolite catalyst to a high level of activity.

Abstract: Improvements in a reforming process for the regeneration and reactivation of a bed of a reforming catalyst, notably an iridium-containing catalyst, coked and catalytically deactivated during the on-oil portion of a reforming cycle. The reactor containing the catalyst is contained in a multi-reactor unit, the individual reactors of which are connected in series via suitable piping and valving. The reactor can be alternately manifolded with production facilities during the on-oil portion of the operating cycle during which period the catalyst of said reactor becomes coked, and can be manifolded alone or with other reactors with a ferrous metal regeneration circuit during the catalyst regeneration and reactivation portion of an operating cycle during which period the catalyst is regenerated and reactivated.

Abstract: A catalyst useful for reforming a naphtha feed at reforming conditions which comprises an iridium component dispersed throughout and bound within an alumina support matrix, a platinum component dispersed upon said iridium-containing alumina support, and halogen. In all of its aspects, the iridium component will remain in its dispersed state, without significant agglomeration, when subjected to temperatures in the presence of oxygen for extended periods sufficient to agglomerate presently known halogenated platinum-iridium catalysts. This catalyst is prepared in an initial step by dispersing the iridium within the alumina matrix, and then calcining the iridium-containing alumina at high temperature to bind the iridium within the alumina support matrix. The platinum, or platinum and additional metal promoters, especially rhenium, is then impregnated upon the iridium-alumina support.

Abstract: A process for the regeneration and reactivation of coked iridium-containing catalysts, and chemical modification and passivation of iron scale carried over from a ferrous metal regeneration circuit to the catalyst-containing reactor, or reactors, to suppress reaction between the iron scale and catalyst as normally occurs when iron scale contacts the catalyst of a reactor, or reactors. The iron scale is rendered non-reactive or inert in the reactor environment by converting the iron scale to a passive form, preferably ferric oxide, by employing ab initio an extended low temperature primary burn while purging the system of carbon oxides, notably carbon monoxide and carbon dioxide. Thereafter, the agglomerated metal, or metals, component of the catalyst is redispersed at conditions insufficient to reduce the oxidized iron scale which is contained in admixture with the regenerated catalyst.

Abstract: A process is described for rejuvenating a coke-deactivated noble metal-containing zeolite catalyst material which comprises removing coke from a non-sulfided catalyst by contacting the catalyst with oxygen only in the presence of sulfur dioxide, and thereafter reducing the catalyst in the presence of a reducing agent such as hydrogen. The process permits catalyst reactivation by burning off coke from the catalyst while avoiding excessive agglomeration of the noble metal thereon.

Abstract: A process is described which improves the performance of cyclic dewaxing/regeneration processes using a catalyst comprising palladium and a zeolite having the structure of Zeolite Beta. The cyclic process includes regenerating the catalyst by oxidation alone or combinations of oxidation and reduction to substantially restore catalyst activity.

Abstract: Method for effecting multiple treatment steps needed to regenerate spent hydrocarbon conversion catalyst. Catalyst is contacted with a hot oxygen-containing gas stream in order to remove coke which accumulates on the catalyst while it is in a hydrocarbon conversion zone. After the coke is burned off in a combustion zone, catalyst is passed into a halogenation zone wherein a halogen is deposited on the catalyst. Catalyst leaving the halogenation zone is passed into a drying zone for removal of water formed in the combustion zone which has remained on the catalyst instead of being carried off with combustion gases. Water removal is accomplished by passing a hot dry air stream through the catalyst in the drying zone.

Abstract: Apparatus for effecting multiple treatment steps needed to regenerate spent hydrocarbon conversion catalyst. Catalyst is contacted with a hot oxygen-containing gas stream in order to remove coke which accumulates on the catalyst while it is in a hydrocarbon conversion zone. After the coke is burned off in a combustion zone, catalyst is passed into a halogenation zone wherein a halogen is deposited on the catalyst. Catalyst leaving the halogenation zone is passed into a drying zone for removal of water formed in the combustion zone which has remained on the catalyst instead of being carried off with combustion gases. Water removal is accomplished by passing a hot dry air stream through the catalyst in the drying zone.

Abstract: A method for reactivating noble metal-containing zeolites containing sulfur oxide poisoned noble metal such as oxygen regenerated platinum zeolite beta catalysts, by contacting the catalyst with an acidic aqueous solution having a pH below about 7. The solution contains a Bronsted acid compound having a dissociation constant ranging from about 1.times.10.sup.-14 to about 2.times.10.sup.-1.

Abstract: A process is described for rejuvenation of a deactivated highly siliceous noble metal-containing zeolite catalyst having a framework silica to alumina ratio of at least about 20 which contains agglomerated noble metal in its deactivated state. The process comprises redispersing the noble metals associated with the deactivated catalyst by contacting the catalyst with a stream of inert gas containing molecular chlorine, water and optionally, oxygen, a temperatures ranging from about 150.degree. to about 450.degree. C., a partial pressure of chlorine of from about 6 to about 15 Torr and a ratio of partial pressure of water to partial pressure of chlorine of from about 0.01 to about 2 for a period of time sufficient to achieve redispersion; purging said catalyst with an inert gas; and reducing said purged catalyst in a stream of hydrogen at a temperature ranging from about 140.degree. C. to 550.degree. C.

Abstract: A coke-deactivated noble metal-containing catalyst is sulfided with a sulfiding agent, e.g., H.sub.2 S in H.sub.2, then coke is burned from the sulfided catalyst by contacting the catalyst with oxygen, optionally in the presence of sulfur dioxide, and then the catalyst is reduced with a reducing agent, e.g., H.sub.2. The process permits burning off coke while avoiding excessive agglomeration of the noble metals on the catalyst.

Abstract: A vessel for effecting multiple treatment steps needed to regenerate spent hydrocarbon conversion catalyst. Regeneration is accomplished by means of a moving bed of catalyst, where catalyst is passed through several treatment zones in the regeneration vessel. Catalyst is contacted with a hot oxygen-containing gas stream in order to remove coke which accumulates on the catalyst while it is in a hydrocarbon conversion zone. After the coke is burned off in a combustion zone, catalyst is passed into a drying zone for removal of water formed in the combustion zone which has remained on the catalyst instead of being carried off with combustion gases. Water removal is accomplished by passing a hot dry air stream through the catalyst. This air stream is introduced into the bottom of the regeneration vessel and is heated by exchange of heat with catalyst, thereby effecting the required cooling of the catalyst. Before passing into the drying zone, the air is heated further by heating means located in the vessel.

Abstract: A process is described for rejuvenation of a deactivated highly siliceous noble metal-containing zeolite catalyst which contains agglomerated noble metals. The process comprises initially reducing the deactivated catalyst in hydrogen, pretreating the thus reduced catalyst with an inert gas stream containing about 0.001 to 10 weight percent hydrogen chloride, redispersing the noble metal with an inert gas stream containing about 0.001 to 10 weight percent Cl in the form of Cl.sub.2 or Cl-containing organic material, and subsequently reducing the catalyst. The Cl-treatments may optionally occur in the presence of oxygen or sources of oxygen.

Abstract: Process for sampling particulate matter in a downwardly movable bed thereof which is successively contacted by two different process gases, the second of which is moving upwardly, in such a manner that the particulate matter sampled will be fully representative of particles which have been fully contacted by the first process gas but which have not been contacted by the upwardly moving second process gas. The particulate matter is passed downwardly in the shape of an annular bed through a first annular treatment zone while the major portion of the first process gas is passed through the annular bed in a radially inward direction. The annular bed is then passed downwardly along with a small amount of the first process gas from the first treatment zone through an elongated transition zone and into the radially outermost upper portion of a generally cylindrical second treatment zone.

Abstract: A catalytic conversion system having sulfur-contaminated vessels and/or conduits upstream from the fixed catalytic bed is regenerated in situ by first flowing regenerating oxygen-containing gas having not more than 0.1 mol percent oxygen and at a temperature of above 850.degree. F., through the normal flow path of the vessels and/or conduits and then the fixed catalyst beds, wherein the sulfur contaminants are oxidized to sulfur dioxide which pass through the catalyst bed in the absence of sufficient oxygen to permit substantial conversion to harmful sulfur trioxide in the presence of catalyst containing a platinum group component on a porous inorganic oxide base, prior to removal of carbonaceous material from the catalyst.

Abstract: A method is disclosed for regenerating particulate catalyst used in a hydrocarbon conversion process such as catalytic reforming. The method is especially applicable to moving bed reactor systems. The catalyst being regenerated slowly moves downward as a dense bed which is contacted with different gas streams at different elevations within the regeneration zone. The invention involves employing a portion of relatively hot combustion gas as a heating gas stream, with the remainder of the combustion gas being cooled and recycled to the combustion zone. This eliminates the need to employ a heater to provide a suitable heating gas stream.

Abstract: Apparatus for transferring particulate contact material by gravity from an upper contact zone wherein it is contacted by a first gas flowing radially, to a lower zone wherein it is contacted by a second gas flowing upwardly. The apparatus includes a generally annular transition zone which connects the upper and lower zones. The transition zone effectively isolates the second gas from contacting the particulate material in the upper zone. In a preferred embodiment in the form of a catalyst regenerator, catalyst particles can be sampled for carbon level in the transition zone to determine if the carbon burn-off therefrom is sufficiently complete in an upper radial flow regenerator bed by contact with a first gas, having a relatively low oxygen level. The sampling can be done on stream, even though a second gas, such as relatively oxygen-rich halogenation gas, is passing up through the catalyst in the lower zone.

Abstract: A process is described for rejuvenating a coke-deactivated noble metal-containing zeolite catalyst material which comprises sulfiding the deactivated catalyst material by contacting with a sulfiding agent such as hydrogen sulfide-containing gas, removing coke from the sulfided catalyst by contacting the catalyst with oxygen in the presence of sulfur dioxide, and thereafter reducing the catalyst in the presence of a reducing agent such as hydrogen. The process permits catalyst reactivation by burning off coke from the catalyst while avoiding excessive agglomeration of the noble metals thereon.

Abstract: A process for removing metal contaminants from a hydroconversion catalyst, said catalyst containing at least one metal from Groups VIB, VIIB or VIII supported on a refractory inorganic oxide. The process comprises contacting the contaminated catalyst with a buffered oxalic acid solution wherein contaminant is removed without dissolving the support.

Abstract: In a process for treatment of a fresh iridium-containing catalyst, the improvement consists of a three step procedure in sequence including treatment with oxygen, treatment with hydrogen chloride, and treatment with a reducing agent such as hydrogen.

Abstract: A process wherein a coked, deactivated iridium-containing catalyst can be reactivated in a sequence of burn steps, inclusive of a low temperature primary burn step and a subsequent high temperature burn step. In (1) the low temperature primary burn step (i) the chloride level of the catalyst is raised and the catalyst passivated by contact with a hydrogen chloride containing gas, (ii) and coke is then burned from the catalyst by contact with a gas which contains hydrogen chloride at level sufficient to suppress iridium agglomeration at a level of oxygen providing burn temperatures which do not exceed about 425.degree. C., this being sufficient to remove a preponderance of the coke without agglomeration of the iridium component.

Abstract: A process wherein a coked, deactivated iridium-containing catalyst can be reactivated in a sequence of burn steps, inclusive of a low temperature primary burn step and a subsequent high temperature burn step. In (1) the low temperature primary burn step (i) the chloride level of the catalyst is raised and the catalyst passivated by contact with a hydrogen chloride containing gas, (ii) and coke is then burned from the catalyst by contact with a gas which contains hydrogen chloride at level sufficient to suppress iridium agglomeration at a level of oxygen providing burn temperatures which do not exceed about 425.degree. C., this being sufficient to remove a preponderance of the coke without agglomeration of the iridium component.

Abstract: The process of oxidatively regenerating in situ a fixed bed hydrocarbon catalyst which is sensitive to reactive sulfur compounds in a conversion system having sulfur-contaminated vessels and/or conduits in the flow path upstream from said catalyst is improved by passing regenerating oxygen-containing gas first through the sulfur-contaminated vessels and/or conduits and then through the fixed catalyst bed while limiting the water content of the regenerating gas to a concentration of not more than 0.1 mol percent throughout the flow path and at a temperature in the range of 750.degree.-1100.degree. F. to oxidize the sulfur contaminants in the vessels and/or conduits upstream from the catalyst. Thereby the evolved sulfur oxides flow through the fixed bed catalyst in the absence of sufficient water which would promote reaction of sulfur oxides with the catalyst.

Abstract: A multiple-stage catalytic conversion system in which a hydrocarbonaceous charge stock and hydrogen flow serially through a plurality of catalytic reaction zones in each of which the catalyst particles are movable via gravity flow. Dissimilar catalyst particles are utilized in the reactor systems which share a common regenerating tower through which the catalyst particles are downwardly movable via gravity flow and in which the catalyst particles are regenerated in segregated fashion. Dissimilarity of the catalyst particles stems from a difference in activity, stability and selectivity characteristics. In turn, this difference may be attributed either to physical, or chemical distinctions between the two composites, or both.

Abstract: The invention relates to a process for the regeneration of an aromatization catalyst containing a metal of Group VIII supported on zeolite, the process being such that the catalyst is subjected to combustion, and then to oxychloration.According to the invention, the oxychloration step is followed by a hydratation step.The treatment according to the invention increases the selectivity of the regenerated catalyst.

Abstract: A process is disclosed for reactivating a coked and agglomerated iridium and selenium containing catalyst and particularly platinum-iridium-selenium on alumina reforming catalysts. The process includes a low temperature decoking step to achieve partial decoking while minimizing agglomeration, a reducing step involving contacting the decoked agglomerated catalyst with a reducing gas such as hydrogen to reduce agglomerated iridium oxides to the free metal, a halide pretreatment step to increase the chloride level of the catalyst to about 1.3 weight percent and above, and a halogen redispersion step. The redispersion step is performed with a mixture of elemental halogen and water vapor.

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 a reducing step involving contacting a decoked agglomerated catalyst with a reducing gas such as hydrogen to reduce agglomerated iridium oxides to the free metal, a hydrogen halide pretreatment step to provide a halide level to the catalyst of about 1.3 weight percent, and an elemental halogen/oxygen or wet oxygen redispersion step. The hydrogen halide pretreatment step is performed under elemental oxygen-free conditions prior to redispersion and allows high iridium redispersion values to be obtained. If no iridium oxides are initially present, the hydrogen step is optional.

Abstract: A method is disclosed for regenerating reforming catalysts containing a platinum group component and/or rhenium component in association with a halogen component on a porous inorganic oxide, such as one containing alumina without significant displacement of the rhenium components by sulfur oxides generated during the regeneration process. The method is particularly characterized in that carbon is removed from the catalyst by in situ oxidation at temperatures not in excess of about 750.degree. F. and without modification of the catalytic reforming process flow circuit, as by disconnecting or isolating the heat exchangers and furnace tubes.Sulfide scale is converted in a separate oxidation step to sulfur dioxide, SO.sub.2, without substantial oxidation to sulfur trioxide, SO.sub.3, by maintaining the inner walls of the heat exchangers and furnace tubes, where such iron sulfides are present, at a temperature not in excess of about 900.degree. F. and not less than about 750.degree. F.

Abstract: A process is described for reactivating agglomerated iridium-containing catalysts such as Pt-Ir on Al.sub.2 O.sub.3 reforming catalyst. The agglomerated catalyst is decoked to remove carbon deposits; treated with hydrogen to reduce metal oxides to the free metals; pretreated with hydrogen halide to provide at least about a 1.3 weight percent halide content; and treated with a low mass flow rate of chlorine of about one gram chlorine per 100 grams catalyst per hour. Use of a low mass halogen flow rate significantly retards ferrous metal corrosion and significantly reduces the quantity of chlorine normally used in achieving high redispersion values.

Abstract: A process is disclosed for reactivating an agglomerated iridium-containing catalyst and particularly platinum-iridium on alumina reforming catalysts. The process includes a reducing step involving contacting a decoked agglomerated catalyst with a reducing gas such as hydrogen to reduce agglomerated iridium oxides to the free metal, a hydrogen halide pretreatment step to provide a halide level to the catalyst of about 1.3 weight percent, and an elemental halogen redispersion step. The hydrogen halide pretreatment step is performed under elemental oxygen-free conditions prior to redispersion and allows high iridium redispersion values to be obtained. If no iridium oxides are initially present, the hydrogen step is optional.

Abstract: A process is disclosed for reactivating a coked and agglomerated iridium-containing catalyst and particularly platinum-iridium on alumina reforming catalysts. The process includes a low temperature decoking step to achieve partial decoking while minimizing agglomeration, a reducing step involving contacting the decoked agglomerated catalyst with a reducing gas such as hydrogen to reduce agglomerated iridium oxides to the free metal, a halide pretreatment step to increase the chloride level of the catalyst to about 1.3 weight percent and above, and a halogen redispersion step. The redispersion step is performed with a mixture of elemental halogen and water vapor.

Abstract: A process is disclosed for reactivating agglomerated iridium-containing catalysts, in series, and particularly platinum-iridium on alumina reforming catalysts. The process includes a reducing step, involving contacting a decoked agglomerated catalyst with a reducing gas, such as hydrogen, to reduce agglomerated iridium oxides to the free metal, a halide pretreatment step to increase the halide level of the catalyst to about 1.3 weight percent and above, a halogen/water vapor redispersion step at elevated temperature and a contacting of a second catalyst, in series, with the halogen/water vapor effluent at elevated temperature to partially burn-off the carbon deposits on the catalyst surface. Utilizing the effluent halogen stream, rather than subjecting to a scrubbing operation represents a savings in process costs, minimizes pollution problems and provides additional halogen protection to subsequent catalyst reactors in the process scheme.

Abstract: A process is described for the redispersion of iridium-containing catalysts involving a low temperature hydrogen reduction step, i.e., from 190.degree. C. up to about 250.degree. C. after a coke burn-off. The low temperature reduction step allows milder conditions during subsequent halogen redispersion.

Abstract: A process is disclosed for reactivating an agglomerated iridium-containing catalyst and particularly platinum-iridium on alumina reforming catalysts. The process includes a reducing step involving contacting a decoked agglomerated catalyst with a reducing gas such as hydrogen to reduce agglomerated iridium oxides to the free metal, a hydrogen halide pretreatment step to provide a halide level to the catalyst of about 1.3 weight percent, and an elemental halogen redispersion step. The hydrogen halide pretreatment step is performed under elemental oxygen-free conditions prior to redispersion and allows high iridium redispersion values to be obtained. If no iridium oxides are initially present, the hydrogen step is optional.

Abstract: A process is described for reactivating agglomerated iridium-containing catalysts such as Pt-Ir on Al.sub.2 O.sub.3 reforming catalyst. The agglomerated catalyst is decoked to remove carbon deposits; treated with hydrogen to reduce metal oxides to the free metals; pretreated with hydrogen halide to provide at least about a 1.3 weight percent halide content; and treated with a low mass flow rate of chlorine of about one gram chlorine per 100 grams catalyst per hour. Use of a low mass halogen flow rate significantly retards ferrous metal corrosion and significantly reduces the quantity of chlorine normally used in achieving high redispersion values.

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: A process for the production of aromatic hydrocarbons from petroleum fractions containing paraffins which comprises passing said charge in the presence of hydrogen at 400.degree. C.-550.degree. C. over a catalyst containing from 0.1 to 1.5% by weight of at least one metal selected from the group consisting of platinum, rhenium, iridium, tin and germanium and containing sulfur in a sulfur/metals atomic ratio of from 0 to less than 1, supported on a crystalline, aluminum silicate zeolite containing alkaline cations, said zeolite having a pore dimension larger than 6.5 Angstroms, wherein the catalysts are in fixed beds in two reactors or sets of reactors arranged in parallel and operate at a pressure on the order of from 0.5 to 8 absolute bars wherein when a reactor set (DHC.sub.1 ) is producing aromatic hydrocarbons the other reactor set (DHC.sub.2 ) is swept by the hydrogen produced by the first reactor set (DHC.sub.

Abstract: A process for regenerating, and reactivating, coked noble metal catalysts, especially platinum-containing polymetallic catalysts in a system which includes separate, interconnected primary and secondary regeneration gas circuits in which gas is circulated from one circuit to the other, (i) a primary regeneration gas circuit which contain a preheat gas furnace, a reactor which contains said catalyst from which said coke can be burned by contact with hot gas from said preheat gas furnace, and a steam boiler through which said hot gas can be passed and cooled, and the cool gas injected, or returned to said secondary circuit; and (ii) the secondary circuit is one which contains a regeneration gas scrubber, a gas drier (optional) and fines solids filter. The circuit also includes regeneration gas means, i.e. a compressor, for circulating the gas in said circuits.