Abstract: A system for optimizing start-up of an amine regeneration system comprising a rich/lean heat exchanger, a still, a reflux condenser, a reflux accumulator, a pump, a reboiler, and a reflux accumulator fill line assembly.

Abstract: Nitrogen oxide storage catalysts are used for removing the nitrogen oxides present in the lean-burn exhaust gas of lean-burn engines. Here, the purifying action is based on the nitrogen oxides being stored in the form of nitrates by the storage material of the storage catalyst during a lean-burn operating phase of the engine and the previously formed nitrates being decomposed in a subsequent rich-burn operating phase of the engine and the nitrogen oxides which are being liberated again being reacted with the reducing exhaust gas constituents over the storage catalyst to form nitrogen, carbon dioxide and water. Storage catalysts are thermally aged by high temperatures. The aging is due to sintering of the catalytically active noble metal components of the catalyst and to formation of compounds of the storage components with the support materials.

Abstract: A process for cleaning gases from a gasification unit comprising the steps of: gasifying a fuel to raw synthesis gas comprising carbon monoxide and steam in a gasification reactor in the presence of a calcium-containing compound and steam removing halogen compounds from the raw synthesis gas catalytic conversion of carbon monoxide and steam in the raw synthesis gas to carbon dioxide and hydrogen in a water gas shift conversion step to provide a shifted gas contacting the shifted gas with a solid sulphur sorbent regenerating the solid sulphur sorbent by passing a stream of steam through the solid sulphur sorbent counter current to the flow direction of the shifted gas to provide a hydrogen sulphide-containing stream of steam transferring the hydrogen sulphide-containing stream of steam from the solid sulphur sorbent directly to the gasification reactor removing the cleaned shifted gas from the solid sulphur sorbent.

Abstract: A gas stream containing e.g. molecular hydrogen is used for the regeneration of a catalyst for NOx and SO2 removal from the flue gas of a gas turbine. In order to reduce the consumption of regeneration gas, the gas inlet is located between the SCOSOx catalyst (2) and the SCONOx catalyst (3). The regeneration gas leaves the catalyst chamber upstream of the SCOSOx catalyst and is recycled. For the regeneration of the SCONOx catalyst and to keep SO2 containing gas from entering the SCONOx catalyst, a second regeneration gas inlet is located downstream of the SCONOx catalyst. The regeneration gas entering the catalyst chamber through this port passes the SCONOx (3) and the SCOSOx catalyst (2). The direction of the flow in the SCONOx catalyst can also be reversed. In another example, regeneration gas outlets are located both upstream of the SCOSOx and downstream of the SCONOx catalyst. But, only the regeneration gas from the SCONOx catalyst is recycled.

Abstract: This invention provides processes, systems and devices for cooling catalyst, preferably regenerated catalyst, by superheating steam and boiling water. The inventive process advantageously provides ideal cooling conditions while ensuring minimal hydrothermal deactivation of the catalyst during the cooling process. The invention is particularly well-suited for cooling catalyst in an oxygenate to olefins reaction system.

Abstract: The current invention provides methods and apparatus for integrating a high temperature waste heat recovery system with a chemical or refining process which requires heat energy at a temperature less than the operational temperature of the waste heat recovery system. Additionally, the current invention provides methods and apparatus suitable for retrofitting existing process units requiring heat energy at a temperature of T2 with a waste heat recovery system operating at temperature of T1 where T1 is greater than T2.

Abstract: The present invention relates to the regeneration of a SOx removal catalyst (14) and a NOx reducing catalyst (12). Additionally, this invention relates to the reduction or elimination of sulfur breakthrough from the SOx removal catalyst (14) to the NOx reducing catalyst (12) that may occur during or after a regeneration sequence.

Abstract: The invention is directed to a method of rejuvenating silicoaluminophosphate molecular sieve catalyst that has been deactivated hydrothermally as well as a method of using the rejuvenated catalyst to make an olefin product from an oxygenate feed. In particular, the invention is directed to rejuvenating the catalyst by contacting it with warm water, ammonium salts, dilute acids or low pressure steam until the catalytic activity level of the catalyst has been increased to the desired extent.

Abstract: The invention is directed to a method of rejuvenating silicoaluminophosphate molecular sieve catalyst that has been deactivated hydrothermally as well as a method of using the rejuvenated catalyst to make an olefin product from an oxygenate feed. In particular, the invention is directed to rejuvenating the catalyst by contacting it with warm water, ammonium salts, dilute acids or low pressure steam until the catalytic activity level of the catalyst has been increased to the desired extent.

Abstract: Nitrogen oxide storage catalysts are used for removing the nitrogen oxides present in the lean-burn exhaust gas of lean-burn engines. Here, the purifying action is based on the nitrogen oxides being stored in the form of nitrates by the storage material of the storage catalyst during a lean-burn operating phase of the engine and the previously formed nitrates being decomposed in a subsequent rich-burn operating phase of the engine and the nitrogen oxides which are being liberated again being reacted with the reducing exhaust gas constituents over the storage catalyst to form nitrogen, carbon dioxide and water. Storage catalysts are thermally aged by high temperatures. The aging is due to sintering of the catalytically active noble metal components of the catalyst and to formation of compounds of the storage components with the support materials.

Abstract: The present invention relates to a process for stripping hydrocarbons from a catalyst, comprising the step of contacting the catalyst with steam at stripping conditions, wherein the catalyst comprises a molecular sieve having a structure type of MWW, the steam comprises at least 90 wt. % vapor phase H2O, the stripping conditions comprise a temperature range from about 100° C. to about 250° C., a pressure less than 310 kpa-a, and a WHSV range from about 0.01 to about 100 hr?1.

Abstract: A method and apparatus are disclosed for regenerating calcium oxide used in the production of hydrogen gas. The method includes steps of: (a) streaming a solid reactant into an inlet port of a contactor vessel; (b) streaming a purge oxidant into an oxidant port of the contactor vessel to reduce a partial pressure of a gas over the solid reactant; (c) venting the gas from a gas port of the contactor vessel; and (d) removing the solid reactant from a discharge port of the contactor vessel.

Abstract: This invention provides processes for transporting catalyst, preferably in an oxygenate to olefins reaction system. In one embodiment, an oxygenate contacts molecular sieve catalyst particles in a reactor under conditions effective to form an effluent stream comprising light olefins and forming coked catalyst particles. At least a portion of the coked catalyst particles are transported from the reactor or a device associated therewith to a catalyst regenerator through a conduit in a fluidized manner with a fluidizing medium comprising air and steam. At least a portion of the coked catalyst particles are regenerated in the catalyst regenerator to form regenerated catalyst particles, which are ultimately directed back to the reactor.

Abstract: Treatment with steam, especially at sub-atmospheric pressure, rejuvenates deactivated zeolites that have been used as catalysts for liquid phase or dense phase oligomerization.

Abstract: Process for the regeneration of exhausted catalysts, containing one or more calcium aluminates, for steam cracking reactions, comprising treating said exhausted catalysts in a stream of water vapour at a temperature ranging from 700 to 950° C., preferably from 720 to 850° C., and at a pressure ranging from 0.5 to 2 atm.

Abstract: A process for preparing a Fischer-Tropsch catalyst comprising the steps of a) providing a particle comprising a support and having a catalytically active metal homogenously distributed therein, wherein at least 50 wt % of the catalytically active metal is present as divalent oxide or divalent hydroxide; b) treating the particle with a water vapour comprising gas having a relative humidity of at least 80% or with liquid water for at least two hours; and c) drying the catalyst particle.

Abstract: Disclosed herein are sorbents and devices for controlling sulfur oxides emissions as well as systems including such sorbents and devices. Also disclosed are methods for making and using the disclosed sorbents, devices and systems. In one embodiment the disclosed sorbents can be conveniently regenerated, such as under normal exhaust stream from a combustion engine, particularly a diesel engine. Accordingly, also disclosed are combustion vehicles equipped with sulfur dioxide emission control devices.

Abstract: An apparatus for treatment of a plurality of molecular sieves samples is described. The apparatus comprises a steam preparation section, a steam reactor section, and a steam collection section. The steam preparation section includes a steam generator, and a means to supply inert gas into the steam reactor section. The steam reactor section includes a plurality of sample holders. The steam collection section includes a plurality of knock-out vessels. The steam reactor section is operatively connected to the steam preparation section, and the steam collection section is operatively connected to the steam reactor section. In one embodiment, each sample holder is connected and operated in tandem with one knock-out vessel. A process for treating a plurality of molecular sieves samples with steam is also disclosed which may be carried out with the described apparatus.

Abstract: A method of regenerating an absorbent includes preparing a reactor having a gas inlet portion and a discharge portion, filling the reactor with a reforming catalyst and an absorbent for absorbing carbon dioxide, feeding the feedstock gas and the steam via the gas inlet portion to the reactor to allow a steam reforming reaction to take place, allowing the absorbent to absorb carbon dioxide generated with hydrogen at the steam reforming reaction, and releasing the carbon dioxide from the absorbent after the carbon dioxide absorption capacity of the absorbent has been degraded. In this method, the temperature in an inside of the reactor is set to 625° C. or more at the release of the carbon dioxide, and an inert gas is fed via the discharge portion to the reactor.

Abstract: Finely divided ferrous carbonate absorbent, siderite granules or absorbent particles made by mixing, agglomerating and shaping finely powdered ferrous carbonate, preferably siderite, in combination with minor effective amounts of water or an optional binder, followed by drying, are used to treat and significantly reduce concentrations of hydrogen sulfide, carbonyl sulfide, organic disulfides, mercaptans and other sulfurous compounds and contaminants in gaseous and liquid fluid streams such as natural gas, light hydrocarbon streams, crude oil, acid gas mixtures, carbon dioxide gas and liquid streams, anaerobic gas, landfill gas, geothermal gases and liquids, and the like. Methods for absorbing sulfur compounds in a moist atmospheric environment and for regenerating the absorbent by contacting it with air and steam or, continuously, by mixing the feed stream with moist air are also disclosed.

Abstract: A mixed metal oxide, which may be an orthorhombic phase material, is regenerated, selectively enriched or selectively poisoned as a catalyst to reduce catalyst aging for the production of unsaturated carboxylic acids, or unsaturated nitrites, from alkanes, or mixtures of alkanes and alkenes, by contacting said mixed metal oxide with a an oxidizing gas such as oxygen, air, steam and combinations thereof is permitted to flow through the catalyst in a regenerator at a temperature of from 300° C. to 600° C. to form said regenerated catalyst.

Abstract: A zeolite and an organic binder are mixed with a solvent to form a paste (302). The paste is then cast or molded (304) into the desired shape. A portion of the solvent is allowed to evaporate from the paste, hardening the getter (306). Getters are often formed in sheets and cut (308) into individual pieces, called dibs, after the sheets have hardened. Even after the getter is hardened, significant amounts of solvent are retained by the getter. The getter is exposed to water vapor which displaces (310) the solvent from the getter. After the solvent is removed, the getter is dried (312) to remove additional water vapor. Because the water vapor does not bind as tightly to the zeolite getter, the water vapor is removed much easier than the solvent. The water may be removed by allowing the getter to dry naturally, or by a vacuum bake process.

Abstract: The present invention is to solve the problems caused by a conventional method for producing a zinc chloride-loaded support wherein zinc chloride is adsorbed on a solid support in an aqueous solution of zinc chloride. The problems include environmental destruction caused by the treatment of a used aqueous solution of zinc chloride, corrosion to a reactor, a threat to health for workers, deterioration of zinc chloride due to deliquescence thereof, and reduction of specific surface area.

Abstract: Process and device for regeneration of a used absorbent from a desulfurization zone or from the desulfurization of a gas containing sulfur oxides, comprising regeneration simultaneously with filtering of the absorbent, in a reducing atmosphere, wherein partial combustion of a regeneration gas is also carried out upstream from regeneration, the products of the partial combustion being mixed with the used absorbent prior to the regeneration-filtration stage. The absorbent may be, e.g., solid absorbents based on magnesium oxide. The regeneration gas may be hydrogen sulfide and/or a hydrocarbon. For example, H2S can be partially combusted and the products of the partial combustion, including H2S, H2, SO2 and sulfur, mixed with the used absorbent prior to the regeneration-filtration stage.

Abstract: A gas stream containing e.g. molecular hydrogen is used for the regeneration of a catalyst for NOx and SO2 removal from the flue gas of a gas turbine. In order to reduce the consumption of regeneration gas, the gas inlet is located between the SCOSOx catalyst (2) and the SCONOx catalyst (3). The regeneration gas leaves the catalyst chamber upstream of the SCOSOx catalyst and is recycled. For the regeneration of the SCONOx catalyst and to keep SO2 containing gas from entering the SCONOx catalyst, a second regeneration gas inlet is located downstream of the SCONOx catalyst. The regeneration gas entering the catalyst chamber through this port passes the SCONOx (3) and the SCOSOx catalyst (2). The direction of the flow in the SCONOx catalyst can also be reversed. In another example, regeneration gas outlets are located both upstream of the SCOSOx and downstream of the SCONOx catalyst. But, only the regeneration gas from the SCONOx catalyst is recycled.

Abstract: A stripper and a stripping process for removing the flue gas carried by regenerated catalyst. A cylindrical stripper mainly comprises a degassing pipe at the longitudinal axis, a horizontal pipe connected with the lower end of the degassing pipe, several sets of inner annular baffles and outer annular baffles arranged in alternative arrangement along the vertical direction. Inner annular baffles are fixed on the degassing pipe, outer annular baffles are fixed on the inner wall of the cylinder. The degassing pipe has holes below each set of the inner annular baffles. The regenerated catalyst enters the stripper from the upper part, comes into a countercurrent and crosscurrent contact with steam from the annular steam conduit, and the stripped regenerated catalyst leaves the stripper from the bottom.

Abstract: There is provided a process for regenerating the activity of used metal catalysts for the hydrogenation of carbon monoxide comprising decreasing the hydrocarbon content thereof, calcining under an oxidant-containing atmosphere, impregnating with a solution of at least one of a metal compound, calcining under an oxidant-containing atmosphere and activating by contacting with a hydrogen-contacting gas at elevated temperatures to form an active catalyst. The process regenerates and enhances both supported and dispersed active metal (DAM) catalysts. Used catalysts enhanced by the process are initially treated to decrease their hydrocarbon content. The treatment may be carried out in a single reactor, or by carrying out up to all steps after catalyst may be withdrawn from a reactor and returned to at least one reactor, both preferably during operation thereof. Up to all steps may be effected in a subsequent reactor, or in specialized apparatus.

Abstract: The invention relates to a process and apparatus for controlling afterburning in the regenerator of a FCC unit. The process and apparatus inject steam into the dilute phase within a regenerator to promote combustion of carbon monoxide before it enters the regenerator cyclones, plenum, or flue gas transfer lines.

Abstract: A process for activating a supported metal catalyst or catalyst precursor useful for the hydrogenation of carbon monoxide to form a mixture of hydrocarbons, comprising reducing with a hydrogen-containing gas at elevated temperature so that at least a portion is in the metallic state, impregnating under a non-oxidizing atmosphere with a solution of at least one member selected from the group consisting of ammonium salts, alkyl ammonium salts and weak organic acids, optionally further including ammonia, to the point where it has absorbed a volume of solution equal to at least about 10% of its calculated pore volume, oxidizing with a gaseous oxidant in the presence of the impregnating solution and reducing with hydrogen-containing gas at elevated temperatures to form an active catalyst. The steps beginning with the impregnation may be repeated. Optionally, the catalyst may be calcined after the oxidation step and/or passivated after activation.

Abstract: Process for the regeneration of exhausted catalysts, containing one or more calcium aluminates, for steam cracking reactions, comprising treating said exhausted catalysts in a stream of water vapour at a temperature ranging from 700 to 950° C., preferably from 720 to 850° C., and at a pressure ranging from 0.5 to 2 atm.

Abstract: The present invention generally relates to a method of thermally reactivating activated carbon via a two-step process: steam followed by pyrolysis; whereby the steam is preferably deoxygenated. Activated carbons reactivated by this method resemble their virgin counterpart's physical characteristics (e.g., BET surface area) and often perform better in water treatment. The present invention also includes a method of reactivating activated carbon via conventional processes (i.e. pyrolysis followed by steam) at low dissolved oxygen (DO) concentrations. The third aspect of the present invention is the activation of carbonaceous material comprising of steam treating the carbonaceous material followed by pyrolysis.

Abstract: A process for working up at least partially deactivated polymerization catalysts for the polymerization or copolymerization of THF which are contaminated with the products of the polymerization or copolymerization of THF comprises (a) in a first step, cleaning the polymerization catalyst by treatment with steam at from 80 to 250° C. and a pressure of from 0.5 to 40 bar and, preferably, (b) in a second step, regenerating the clean polymerization catalyst.

Abstract: The present invention generally relates to a method of thermally reactivating activated carbon via a two-step process: steam followed by pyrolysis; whereby the steam is preferably deoxygenated. Activated carbons reactivated by this method resemble their virgin counterpart's physical characteristics (e.g., BET surface area) and often perform better in water treatment. The present invention also includes a method of reactivating activated carbon via conventional processes (i.e. pyrolysis followed by steam) at low dissolved oxygen (DO) concentrations. The third aspect of the present invention is the activation of carbonaceous material comprising of steam treating the carbonaceous material followed by pyrolysis.

Abstract: One embodiment of the present invention provides a carbon dioxide gas absorbent, which includes at least one compound selected from the group including sodium silicate, potassium silicate, and a combination thereof; and lithium silicate. Another embodiment of the present invention provides A carbon dioxide gas absorbent, which includes at least one compound selected from the group including sodium-based anhydrous water glass, potassium-based anhydrous water glass, and a combination thereof; and lithium silicate. The present invention also provides for methods of making the absorbents and methods of using same.

Abstract: This invention provides a method of reactivating a catalyst for methacrylic acid production, which catalyst is used in production of methacrylic acid through vapor-phase oxidation of methacrolein or vapor-phase oxidative dehydrogenation of isobutyric acid, contains P and Mo, and exhibits reduced activity. The process comprises treating the catalyst, whose activity level has dropped (deteriorated catalyst), with a gas containing a nitrogen-containing heterocyclic compound (e.g., pyridine, piperidine, piperazine, quinoline).

Abstract: Titanium oxide exhibiting a superior photocatalytic activity through irradiation of a visible light as well as an ultraviolet light, and a photocatalyst and a photocatalytic coating agent including said titanium oxide, wherein said titanium oxide has a value of an index X1 calculated by the following equation (I) of not more than about 0.90, and a value of an index Y1 calculated by the following equation (II) of not less than 0.

Abstract: A method for catalytic production of hydroxylated aromatics by exposing zeolite catalyst to a reducing atmosphere to activate said catalyst, and reacting an aromatic with nitrous oxide in the presence of said activated catalyst.

Abstract: The invention relates to a process and apparatus for controlling afterburning in the regenerator of a FCC unit. The process and apparatus inject steam into the dilute phase within a regenerator to promote combustion of carbon monoxide before it enters the regenerator cyclones, plenum, or flue gas transfer lines.

Abstract: The invention concerns a process for fluidising a catalyst or an adsorbent in a furnace which is fixed but the fluidised bed advances, optionally with rotation, in the presence of another inert solid with a granulometry which is different from that of the catalyst or the adsorbent, in the presence of a fluidisation gas, to carry out either stripping of a catalyst or an adsorbent or regeneration of a catalyst or an adsorbent in the furnace.

Abstract: This invention relates to a process for reactivating a dehydrocyclodimerization catalyst. Dehydrocyclodimerization catalysts which contain an aluminum phosphate binder can be deactivated when they are exposed to hydrogen at temperatures above 500° C. The instant process restores substantially all of the catalyst's lost activity. The process involves treating the catalyst with a fluid comprising water and drying the catalyst. The process is employed particularly advantageously in combination with coke removal for reactivating catalysts that contain coke deposits and that have also been hydrogen deactivated. This invention also relates to a method of producing a dehydrocyclodimerization catalyst that is resistant to hydrogen deactivation.

Abstract: Disclosed herein are a cation-exchanged clay mineral comprising a swelling clay mineral with the cations between layers substantially replaced by low-valence metal amine complexes and/or low-valence metal ammine complexes, and a packing material for chromatography using the same. Use of the packing material provides a sharp peak with respect to a highly unsaturated compound. Since the packing material is unlikely to be influenced by a solvent, it is usable for a long time with good stability.

Abstract: The present invention provides a method for maintaining temperature during regeneration of an oxygenate to olefins catalyst using liquid water as a coolant in an amount sufficient either to reduce duty of a catalyst cooler or to avoid the need to use a catalyst cooler altogether. The method also may be used to hydrotreat fresh, non-hydrothermally treated catalyst which may be added to the regenerator and charged back to the conversion reactor along with the regenerated catalyst.

Abstract: The invention concerns a method of cleaning and/or regenerating wholly or partially de-activated catalysts for stack-gas nitrogen scrubbing, in which the catalysts are treated with a washing and/or regenerating liquid, characterized by the washing or regenerating liquid consisting wholly or in part of demineralized water.

Abstract: A process for hydrotreating a hydrocarbon feedstock (1) involving the use of at least one hydrotreatment, particularly hydrodesulfurization, reactor (2) and a fractionation unit (3), which latter contains two distinct injection zones (4, 5) for the hydrocarbon feedstocks, a common zone (8) of vaporization of the light fractions and two distinct draw-off lines (6, 7) for the liquid bottoms; the hydrocarbon feedstock (1) being subjected to a preliminary treatment either in a first hydrodesulfurization reactor (20) the operating conditions of which (P, T, LHSV) may be different from those of the hydrotreatment reactor (2), or in a sweetening apparatus or else in a sulfur trap, the hydrocarbon feedstock being then injected into the first injection zone (4) of the fractionation unit (3), the liquid bottoms being removed through the draw-off line (6) of the injection zone (4) and passed into a hydrotreatment reactor (2), the effluents from said reactor (2) being injected into a second injection zone (5) of the

Abstract: An apparatus for converting carbonaceous raw materials into a carbonized product and activating the product, includes a device for heating the carbonaceous raw materials to form a carbonized product, and equipment for activating the carbonized product and supplying by-product of the activation to the device to help in the heating. The device heats a column of carbonaceous raw materials to pyrolize it and form a carbonized product and vapors and gases. Upward flow of the gases and vapors is restrained so that they flow, with the carbonized product, out of the bottom of the column where they are burned in a combustion box and the resultant hot gases used to heat the column through a tube defining the column. Descending carbonized materials pass rapidly through the combustion box into the equipment which through electical resistance heating and steam, activates the carbonized materials and passes gas and vapor by-products thereby created up into the combustion box to help fuel the heating of the raw materials.

Abstract: A methanol reforming reactor includes a reforming reaction space into which a methanol reforming catalyst is charged. The methanol reforming catalyst is present at the start of the reforming reaction operation in a pre-aged state in the reforming reaction space. A process for pre-aging the methanol reforming catalyst comprises heating at a temperature of between approximately 240° C. and approximately 350° C. and at a load of between approximately 0.5 m3H2/h and approximately 50 m3H2/h per liter of catalyst material in a methanol/water atmosphere. The reactor may be used in fuel-cell-operated motor vehicles for generating hydrogen for the fuel cells by means of the water vapor reforming of methanol.

Abstract: Process for the removal of contaminant compounds containing one or more heteroatoms of sulfur, nitrogen and/or oxygen from hydrocarbon streams characterized in that it comprises:an adsorption step in which said compounds are adsorbed by means of an adsorber essentially consisting of silica gel, possibly modified with one or more metals selected from the elements of groups IVb, Vb, VIb, VIII, Ib, IIb or from tin, lead or bismuth, carried out at a temperature of between 0.degree. and 150.degree. C. and at a pressure of between 1 and 20 atm;an optional washing step with polar solvents or hydrocarbons;and a regeneration step for removing the substances adsorbed by means of thermal treatment in a flow of inert gas carried out at a temperature of between 100.degree. and 200.degree. C.

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: An improvement in the operation of a thermal oxidizer during regeneration of an adsorber, wherein adsorbates collected in the adsorber are removed from the adsorber and introduced into the thermal oxidizer, by regenerative steam passed through the adsorber, to be oxidized in the thermal oxidizer during a regenerative cycle of prescribed duration, regulates the concentration of adsorbates in the regenerative steam passed to the thermal oxidizer such that the concentration of adsorbates introduced into the thermal oxidizer throughout the duration of the regenerative cycle is regulated to avoid excessive deviations from a selected average concentration of adsorbates, the regulated concentration of adsorbates enabling more efficient operation of the thermal oxidizer throughout the full duration of the regenerative cycle.

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.