Abstract: A method of equipment decontamination may include: introducing a cleaning stream comprising hydrogen and a solvent comprising a fatty acid methyl ester and an oxygenated solvent into the equipment; and introducing a stream comprising nitrogen into the equipment, wherein the equipment comprises deposits and other contaminants.

Abstract: A system for depressurizing a molecular sieve used in ethanol production is provided. The ethanol production system includes a plurality of on-line molecular sieve bottles for removing water from ethanol production. When the molecular sieve bottle becomes saturated with water it is taken off-line to depressurize it. The depressurization and removal of water is done from the product discharge end resulting in an approximately 5% to 10% reduction in external energy required to run the ethanol production line.

Abstract: The present invention relates to a process for the oxidative regeneration of a deactivated catalyst comprising molecular sieve to provide a regenerated molecular sieve catalyst, wherein said deactivated catalyst is from one or both of an oxygenate to olefin process and a olefin cracking process, said regeneration process comprising at least the steps of providing a regeneration gas stream comprising oxidant; treating the regeneration gas stream with a liquid adsorbent stream comprising an ethylene glycol in a contaminant absorption zone to remove at least a part of one or more of any water, any alkali metal ion and any alkaline earth metal ion present in the regeneration gas stream to provide a treated regeneration gas stream comprising oxidant; regenerating a deactivated catalyst comprising molecular sieve with the treated regeneration gas stream to provide a regenerated catalyst comprising regenerated molecular sieve.

Abstract: A low-oxygen content exhaust flow produced by an engine that is combusting, on average, a stoichiometric mixture of air and fuel generally contains various unwanted gaseous emissions. The exhaust flow is treated by an exhaust aftertreatment system that includes a three-way-catalyst (TWC) and an ammonia-selective catalytic reduction (ammonia-SCR) catalyst positioned downstream from the TWC in a flow direction of the exhaust flow. The ammonia-SCR catalyst includes (1) a base metal ion-substituted zeolite and/or a base metal ion-substituted silicoaluminophosphate and (2) an oxygen storage material selected from the group consisting of a metal oxide or a mixed metal oxide that exhibits oxygen storage and release capacity. The serial arrangement of the TWC and the ammonia-SCR catalyst enhances the conversion of NOX to N2 in the low oxygen-content exhaust flow produced by the engine and helps prevent ammonia slip to the atmosphere.

Abstract: A composition capable of radiation activated catalysis is provided. The composition comprises a metal compound, a mercapto compound and an olefinic compound. Radiation curable urethane compositions comprising the disclosed composition are also provided. The radiation curable urethane compositions comprise the disclosed composition, a hydroxyl compound and an isocyanate compound. Activation of the composition by radiation in a urethane formulation provides for an efficient method of curing the urethane composition. Coating and adhesive compositions comprising the radiation curable urethane compositions are also provided. In addition, methods for coating and bonding substrates are disclosed.

Abstract: Methods for treating or rejuvenating a spent catalyst are disclosed. Such methods can employ a step of halogenating the spent catalyst, followed by decoking the halogenated spent catalyst.

Abstract: A process for regenerating a molecular sieve absorbent bed used for dehydrating an organic solvent is disclosed. The process is illustrated by regenerating a molecular sieve bed used for dehydrating ethanol, which includes a dehydrating cycle where an ethanol/water vapor mixture is loaded onto the molecular sieve bed at a first temperature to absorb water and recover a substantially dehydrated ethanol vapor effluent. In a regeneration cycle, the bed is subjected to a temperature swing technique whereby a dried gas, such as dried CO2, heated to at a second temperature greater than the first temperature, is passed over the molecular sieve bed, optimally in a counter current directional flow with respect to the dehydrating cycle. The process obviates the need for applying a vacuum pressure swing to regenerate the molecular sieve bed. Water and residual ethanol are removed with the CO2 effluent and can optionally be condensed and combined with a feed input for a subsequent dehydrating cycle.

Abstract: A system for effecting the pretreatment therewith of a sorbent comprising a conveying line (105), such as a pipe, and a plurality of solution nozzles operative for purposes of introducing a solution to treat the sorbent. More particularly, the conveying line (105) includes an inlet (107), an outlet (109), and an inner surface (105a) that is operative to define a passageway (190) through which sorbent particles are capable of being transported between the inlet (107) of the conveying line (105) and the outlet (109) of the conveying line (105).

Abstract: A process for regenerating one or more deactivated cobalt comprising Fischer-Tropsch catalyst particle(s), comprising the steps of: (i) oxidising the catalyst particle(s) at a temperature between 20 and 400° C.; (ii) treating the catalyst particle(s) for more than 5 minutes with a solvent, which solvent comprises an amine, (iii) drying the catalyst particle(s); and (iv) optionally reducing the catalyst particle(s) with hydrogen or a hydrogen comprising gas. This process may be preceded by a step in which Fischer-Tropsch product is removed from the catalyst particle(s).

Abstract: A process for regenerating a used acidic ionic liquid catalyst, comprising: a. contacting the catalyst and hydrogen with a supported hydrogenation catalyst under hydrogenation conditions; and b. recovering a conjunct polymer that is a clear and colorless oil from the catalyst. A process for regenerating a used acidic ionic liquid catalyst which has been deactivated by conjunct polymers comprising the steps of contacting the used catalyst and hydrogen with a supported hydrogenation catalyst in a reaction zone under hydrogenation conditions in the presence of an inert hydrocarbon in which saturated conjunct polymers are soluble for a time sufficient to hydrogenate at least a portion of the conjunct polymers; and recovering the saturated conjunct polymers. Also, a process comprising: contacting the used acidic ionic liquid catalyst and hydrogen with a hydrogenation catalyst comprising a hydrogenation component under hydrogenation conditions; and recovering a conjunct polymer that is a clear and colorless oil.

Abstract: The regeneration of HF alkylation acid in an alkylation unit is improved by withdrawing a vapor stream from the HF regenerator tower and condensing the stream to form a liquid fraction which is accumulated in a side distillation zone; the collected liquid fraction, comprising HF acid, water and some stripping medium is distilled in a batch or continuous type operation to drive off the HF acid (along with stripping medium) and the vapor is returned to the regenerator-stripper vessel. The distillation of the sidedraw liquid is continued until the composition of the liquid attains the azeotropic value or as near to that value as desired. The azeotrope, comprising water and acid can then be dropped out of the distillation vessel for disposal by neutralization in the conventional way.

Abstract: Processes are disclosure which comprise alternately contacting an oxygen-carrying catalyst with a reducing substance, or a lower partial pressure of an oxidizing gas, and then with the oxidizing gas or a higher partial pressure of the oxidizing gas, whereby the catalyst is alternately reduced and then regenerated to an oxygenated state. In certain embodiments, the oxygen-carrying catalyst comprises at least one metal oxide-containing material containing a composition having one of the following formulas: (a) CexByB?zB?O?, wherein B=Ba, Sr, Ca, or Zr; B?=Mn, Co, or Fe; B?=Cu; 0.01<x<0.99; 0<y<0.6; 0<z<0.5; and 1<?<2.2; (b) SrvLawBxB?yB?zO?, wherein B=Co or Fe; B?=Al or Ga; B?=Cu; 0.01<v<1.4; 0.1<w<1.6; 0.1<x<1.9; 0.1<y<0.9; 0<z<2.2; and 3<?<5.5).

Abstract: Increased yields of naphtha and increased catalyst activity are obtained in a hydrocracking process by the use of a catalyst containing a beta zeolite and a Y zeolite having a unit cell size from 24.38 to 24.50 angstrom. The catalyst has a relatively high amount of Y zeolite relative to beta zeolite.

Abstract: Disclosed is an optimized process and apparatus for more efficiently and economically carrying out the liquid-phase oxidation of an oxidizable compound. Such liquid-phase oxidation is carried out in a bubble column reactor that provides for a highly efficient reaction at relatively low temperatures. When the oxidized compound is para-xylene and the product from the oxidation reaction is crude terephthalic acid (CTA), such CTA product can be purified and separated by more economical techniques than could be employed if the CTA were formed by a conventional high-temperature oxidation process.

Abstract: A hydrocarbon desulfurization system employing regenerable solid sorbent particulates in a fluidized bed desulfurization reactor. The sulfur-loaded sorbent particulates are continuously withdrawn from the reactor and transferred to a regenerator. A novel solids transport mechanism provides for the safe and effective transfer of the sulfur-loaded sorbent particulates from the high pressure hydrocarbon environment of the reactor to the low pressure oxygen environment of the regenerator.

Abstract: A process for the regeneration of a zeolitic catalyst which is at least partially exhausted by use in the synthesis of optionally substituted methylenedianiline (MDA) and derivatives thereof, or of a mixture of optionally substituted MDA and derivatives thereof, with a higher homologous product the process involving washing said catalyst with an aromatic compound having at least one substitutent on the aromatic ring having activating characteristics with respect to the electrophilic substitution, in liquid or at least partially liquid phase.

Abstract: The present invention pertains to a process for activating a catalyst composition comprising at least one hydrogenation metal component of Group VI and/or Group VIII of the Periodic Table, and an S-containing organic additive, wherein the catalyst is contacted with hydrogen at a temperature between room temperature and about 600° C., preferably about 100-450° C., and prior to or during the contacting with hydrogen the catalyst is contacted with an organic liquid. Preferably, the contacting with the organic liquid is carried out prior to the contacting with hydrogen. The organic liquid may be a hydrocarbon with a boiling range of 150-500° C., preferably white oil, gasoline, diesel, or gas oil or mineral lube oil. It was found that the application of an organic liquid prior to or during the hydrogen treatment results in catalysts with an increased activity. The invention also comprises catalyst made by the above process and the use of such catalyst in hydrotreating.

Abstract: The invention relates to a method for separating and recovering rhodium from reaction products of oxosynthesis, especially reaction products containing cobalt. The invention also relates to the reuse of rhodium as a catalyst for hydroformulation and to a catalyst for hydroformulation itself. The inventive method is characterized by the following: extraction of the organic solution with an aqueous phosphate solution or a phosphate solution, water washing, oxidative treatment of the organic phase, and extraction of the organic phase with an aqueous water-soluble arylphosphine solution.

Abstract: A unified process which couples a unique in situ catalyst regeneration process with a continuous reactive distillation under pressure for the alkylation of light aromatic hydrocarbons such as benzene with C2-C30 olefins using a solid acid alkylation catalyst supported in the reflux zone of a distillation column. Periodic regeneration of the catalyst is carried out with a countercurrent injection of a C4-C16 paraffin below the benzene rectification zone at the top of the column, but above the catalyst zone while the aromatic hydrocarbon reaction feedstock is injected continuously at a point above a rectification zone at the base of the column where the aromatic compound is separated from the paraffin and by-products washed from the catalyst. The use of the C4-C16 paraffin with the aromatic at a mole fraction in the range of 40 to 90% enables a regeneration temperature of about 175-250° C. to be achieved and maintained by adjusting the column pressure and aromatic reflux rate.

Abstract: The present invention has for its object a process and a device for the reduction of radioactive wastes and particularly by regeneration of filters called iodine traps, in particular in nuclear centers and in centers for nuclear studies.

Abstract: A process for regenerating a catalyst, in particular a plate-type or honeycomb catalyst, which has been at least partially deactivated by catalyst poisons, is described. The catalyst is treated with a gaseous reducing agent and with a polyfunctional complex-forming agent, so that the catalyst poisons are removed.

Abstract: The desulfurization of petroleum distillates can be carried out by cyclic low-temperature adsorption of oxidized sulfur compounds with activated carbon followed by regeneration of the activated carbon using an organic solvent. The activated carbon used in the process is commercially available and its surface area that ranges from approximately 500 to 2000 m2/g having a substantial portion of its pores in the range between 10 to 100 Angstroms.

Abstract: Process for the preparation of alkylene oxide, which process comprises passing a feed comprising an organic hydroperoxide and alkene through a bank of at least two serially connected reactors all containing a bed of heterogeneous epoxidation catalyst particles and operated in a cyclic mode, in which process: (a) the first reactor of the cyclically operated bank is put in a position further down this bank, when the activity of the epoxidation catalyst contained therein has decreased to an undesirably low level; (b) in this position the catalyst with decreased activity is contacted with the effluent from the reactor in the preceding position at a temperature which is at least 5° C. higher than the final temperature at which the catalyst was in use in the first position of the bank and for sufficient time to restore its activity to the desired level.

Abstract: The present invention provides a process for regenerating a spent aromatics alkylation or transalkylation catalyst comprising a molecular sieve by contacting the spent catalyst with an oxygen-containing gas at a temperature of about 120 to about 600° C. and then contacting the catalyst with an aqueous medium, such as an ammonium nitrate solution, an ammonium carbonate solution or an acetic acid solution.

Abstract: The present invention pertains to a process for activating a catalyst composition comprising at least one hydrogenation metal component of Group VI and/or Group VIII of the Periodic Table, and an S-containing organic additive, wherein the catalyst is contacted with hydrogen at a temperature between room temperature and about 600° C., preferably about 100-450° C., and prior to or during the contacting with hydrogen the catalyst is contacted with an organic liquid. Preferably, the contacting with the organic liquid is carried out prior to the contacting with hydrogen. The organic liquid may be a hydrocarbon with a boiling range of 150-500° C., preferably white oil, gasoline, diesel, or gas oil or mineral lube oil. It was found that the application of an organic liquid prior to or during the hydrogen treatment results in catalysts with an increased activity. The invention also comprises catalyst made by the above process and the use of such catalyst in hydrotreating.

Abstract: A slurry catalytic hydrocarbon synthesis process which employs a catalyst comprising a supported cobalt component achieves a short term catalyst half life of more than 10 days, by using a syngas feed which contains less than fifty parts per billion of a combined total amount of HCN and NH3.

Abstract: In a liquid phase carbonylation process for the production of acetic anhydride by reacting a feed stream which includes methyl acetate, methanol and carbon monoxide using a Group VIII metal-containing catalyst, and preferably a rhodium containing material, a liquid reaction product is continuously withdrawn from the carbonylation zone and fed to an evaporation/separation zone for separating volatile constituents of the reaction from the non-volatile constituents which, includes a portion of the Group VIII metal catalyst from the carbonylation reactor. The Group VIII metal catalyst is contacted with a gas stream which includes hydrogen for a period of from about 0.001 seconds to about 200 seconds as it is being returned to the carbonylation zone.

Abstract: Continuous process for the production of prevalently heavy hydrocarbons starting from synthesis gas in the presence of a gas phase, a liquid and a solid catalyst, the above process being carried out using a bubble column, characterized in that the bubble column internally has: (a) at least one draft-tube; (b) at least one device for the inlet of the synthesis gas; (c) at least one device for the inlet of the regenerating gas; (d) at least one device for activating/interrupting the stream of regenerating gas; (e) optional devices suitable for minimizing the mixing of the synthesis gas with the regenerating gas.

Abstract: Platinum metal-containing catalyst systems, which comprise at least one platinum metal, a co-catalyst and other salts, and which are used for the production of diaryl carbonates by the oxidative reaction of aromatic hydroxy compounds with carbon monoxide, can be reactivated by treating the deactivated catalyst system in the liquid phase with an oxidising agent, removing the excess oxidising agent, and reacting the reactivated catalyst system with a carboxylate or diketonate.

Abstract: A reactivation process is disclosed for a catalyst formulated to selectively upgrade naphtha to obtain an isoparaffin-rich product for blending into gasoline. The process utilizes a solid strong-acid catalyst comprising an anion-modified metal oxide, preferably comprising a sulfated support of an oxide or hydroxide of a Group IVB (IUPAC 4) metal, and a platinum-group metal component.

Abstract: Self-heating characteristics of a spontaneously combustible catalyst are reduced by treating spontaneously combustible catalysts with oxygen-containing hydrocarbons having at least 12 carbon atoms. The treatment is particularly suitable for reducing the self-heating characteristics of sulfidable metal oxide(s)-containing catalysts, presulfurized catalysts, presulfided catalysts or reduced catalysts. When applied to sulfur-containing catalysts, the treatment gives a catalyst that has suppressed self-heating properties without substantially compromising sulfur retention or activity. Further, a method of safely unloading a catalyst from a reactor is provided where the catalyst in the reactor is treated with a liquid mixture containing oxygen-containing hydrocarbon having at least 12 carbon atoms to wet the catalyst.

Abstract: The invention pertains to a process for alkylating hydrocarbons in which an alkylatable organic compound is reacted with an alkylation agent to form an alkylate in the presence of a catalyst comprising a hydrogenating function and a solid acid constituent, with the catalyst being subjected intermittently to a regeneration step by being contacted with a feed containing a saturated hydrocarbon and hydrogen, said regeneration being carried out at 90% or less of the active cycle of the catalyst, with the active cycle of the catalyst being defined as the time from the start of the feeding of the alkylation agent to the moment when 20% of the alkylation agent leaves the catalyst-containing reactor section without being converted, not counting isomerization inside the molecule. The process according to the invention is especially attractive for the alkylation of isobutane with one or more butenes to form an alkylate with a high RON.

Abstract: Hydrogen containing tail gas from a hydrocarbon synthesis reactor is used as a hydrogen containing catalyst rejuvenating gas. If CO is present, the CO content, is less than 10 mole % of the gas and the H.sub.2 to CO mole ratio is greater than 3:1. At least a portion of the water and liquid hydrocarbons are removed from the tail gas, before it is used to rejuvenate the reversibly deactivated catalyst.

Abstract: A reversibly deactivated, particulate catalyst in a hydrocarbon synthesis slurry is rejuvenated by circulating the slurry from a slurry body through (i) a gas disengaging zone to remove gas bubbles from the slurry and increase its density, (iii) a downcomer which feeds the gas reduced, dense slurry into the bottom of a rejuvenating tube and applies a positive hydrostatic pressure to the tube, (iii) a catalyst rejuvenation zone in which a catalyst rejuvenating gas, which also acts as a lift gas, contacts the catalyst in slurry to form a catalyst rejuvenated slurry and, (iv) back into the slurry body. Removing gas bubbles prior to rejuvenation improves the rejuvenation efficiency and the downcomer reduces the amount of rejuvenation gas required to maintain slurry circulation through the tube.

Abstract: A method is provided for improving the catalytic activity of an alcohol synthesis catalyst. In this method, the catalyst, after activation by exposure to a reducing atmosphere, is improved by contacting with a carbon dioxide-containing gas to convert the zinc oxide in the catalyst to zinc carbonate. This improvement step occurs in situ preferably in the same reactor as used for the synthesizing of the alcohol.

Abstract: The invention relates to a process for the regeneration of a deactivated, carbon-covered, fine-grained, heat-resistant catalyst, a pumpable suspension of deactivated catalyst being injected into a hot gas stream and the regenerated catalyst then being separated off from the gas stream.

Abstract: A concentrated catalyst solution provided in the carbonylation reaction in which methyl acetate or dimethyl ether is chemically bonded with carbon monoxide in the presence of a catalyst system comprising a rhodium compound and an alkali metal iodide to produce acetic anhydride is subjected to a carbonylation treatment with carbon monoxide or a mixture of carbon monoxide and hydrogen before it is applied to a process for separating the tar contained in the catalyst solution, thereby increasing the iodide ion content of the catalyst solution, thus enabling the rhodium compound to be stabilized.When the concentration of the iodide ion in the concentrated catalyst solution is increased by this method, there is no possibility of the balances between the rhodium concentration and, the alkali metal concentration and the iodine concentration of the carbonylation reaction system being disturbed even when the catalyst solution as reprocessed is returned to the carbonylation reaction system.

Abstract: For the impregnation into the pores of a hydrocarbon treatment catalyst of a sulfurizing agent chosen from element sulfur and organic polysulfides with the aid of a solvent, the impregnation process totally or partially comprises a constituent of the olefin or olefin fraction type, e.g., of the vegetable oil type, or a similar constituent. The use of such a constituent makes it possible to significantly reduce the exothermal effect which occurs during presulfurization, compared with the exothermal effects obtained without using such a constituent.

Abstract: Catalytic composites of the reaction product of a metal halide having Friedel-Crafts activity with the bound surface hydroxyl group of inorganic oxides and containing a zerovalent metal with hydrogenation activity, often are effective catalysts in motor fuel alkylation which, however, undergo rapid deactivation. Deactivated catalysts are readily regenerable by treating the composite from which alkylate feedstock has been removed with hydrogen at temperatures in the range of 10.degree. to 300.degree. C. Multiple regenerations are possible without appreciable activity loss.

Abstract: A concentrated catalyst solution used in a carbonylation reaction in which methyl acetate or dimethyl ether is chemically bonded with carbon monoxide in the presence of a catalyst system comprising a rhodium compound and an alkali metal iodide to produce acetic anhydride is subjected to a carbonylation treatment with carbon monoxide, or a mixture of carbon monoxide and hydrogen, before it is applied to a process for separating the tar contained in the catalyst solution, thereby increasing the iodide ion content of the catalyst solution and enabling the rhodium compound to be stabilized.The balances between the rhodium concentration, the alkali metal concentration and the iodine concentration of the carbonylation reaction system are not disturbed, even when the catalyst solution as reprocessed is returned to the carbonylation reaction system.

Abstract: Catalytic composites of the reaction product of a metal halide having Friedel-Crafts activity with the bound surface hydroxyl group of inorganic oxides and containing a zerovalent metal with hydrogenation activity, often are effective catalysts in motor fuel alkylation which, however, undergo rapid deactivation. Deactivated catalysts are readily regenerable by treating the composite from which alkylate feedstock has been removed with hydrogen at temperatures in the range of 10 to 300.degree. C. Multiple regenerations are possible without appreciable activity loss.

Abstract: The isomerization activity of hydroisomerization catalyst is recovered by subjecting the catalyst to a wash using light aromatic solvents at elevated temperature, e.g. toluene at 300.degree. C. This hot aromatic solvent wash may be preceded by a hot hydrogen containing gas strip. Catalyst activity can be maintained by the continuous or periodic addition of light aromatic solvent or light aromatic containing materials to the feeds sent to the isomerization catalyst.

Abstract: To separate and recover rhodium, the distillation residues of oxo synthesis products are initially treated with an oxidant. Then the reaction mixture is reacted, in the presence of carbon monoxide (or a compound which splits off carbon monoxide), with an aqueous solution of a reagent forming a water-soluble complex compound with rhodium. The reaction mixture breaks into an organic phase and an aqueous phase, the complex goes to the aqueous phase as it is substantially insoluble in the organic phase.

Abstract: A process for regenerating a deactivated hydroformylation catalyst system that contains a rhodium hydridocarbonyl tris(trisubstituted phosphine) complex, a trisubstituted phosphine, and a diphosphinoalkane, is disclosed. The process involves oxidation of the catalyst system, removal of the phosphine oxidation products, and regeneration of the catalyst system by syngas treatment, aqueous extraction, and addition of phosphine ligands.

Abstract: Catalyst in a slurry phase reactor is rejuvenated in said reactor using a substantially vertical draft tube fully immersed in the slurry which utilizes a rejuvenating gas injected substantially near the bottom of the substantially vertical draft tube whereby catalyst near the bottom of the slurry phase reactor is drawn up the draft tube and discharged from the top of the draft tube near the top of the slurry phase in said reactor, control over the rejuvenation temperature in the substantially vertical draft tube being achieved by means of insulating the draft tube and/or fitting the draft tube with heating or cooling means.

Abstract: A cobalt- or ruthenium-containing hydrocarbon synthesis catalyst, subjected to short term, reversible, partial deactivation in a slurry synthesis process can be rejuvenated, i.e., at least about 80+% catalyst activity recovery, by treating the catalyst in the presence of liquid hydrocarbons, preferably the slurry hydrocarbons, with hydrogen at elevated temperatures and pressures.

Abstract: Catalyst in a slurry phase reactor is rejuvenated and uniformly distributed in said reactor using a substantially vertical draft tube fully immersed in the slurry which utilizes a rejuvenating gas injected substantially near the bottom of the substantially vertical draft tube whereby catalyst near the bottom of the slurry phase reactor is drawn up the draft tube and discharged from the top of the draft tube near the top of the slurry phase in said reactor.

Abstract: Catalyst which has become deactivated during a hydrocarbon synthesis (HCS) process is reactivated - rejuvenated using an external reactivation - rejuvenation vessel resulting in a multiple HCS reaction - catalyst rejuvenation reactor vessel design. Flow of the catalyst is synthesis product slurry from the reactor vessel to the rejuvenation vessel and the flow of rejuvenated catalyst back to the reactor vessel are driven by gravity only.

Abstract: A cobalt- or ruthenium-containing hydrocarbon synthesis catalyst, subjected to short term, reversible, partial deactivation in a slurry synthesis process can be rejuvenated, i.e., at least about 80+% catalyst activity recovery, by treating the catalyst in the presence of liquid hydrocarbons, preferably the slurry hydrocarbons, with hydrogen at elevated temperatures and pressures.

Abstract: Catalyst in a slurry phase reactor is rejuvenated and uniformly distributed in said reactor using a substantially vertical draft tube fully immersed in the slurry which utilizes a rejuvenating gas injected substantially near the bottom of the substantially vertical draft tube whereby catalyst near the bottom of the slurry phase reactor is drawn up the draft tube and discharged from the top of the draft tube near the top of the slurry phase in said reactor.