This disclosure describes a method for regenerating a semi-regenerated reforming catalyst. The method comprises adjusting the reaction temperature to 250-480 C., introducing a sulfur-containing naphtha into the reforming reactor, or stopping introducing a feedstock into the reforming reactor, and introducing a sulfur-containing hydrogen into a recycle gas, until the sulfur content in the catalyst is 0.32-0.8 mass %, then the catalyst is subject to coke-burning, oxychlorination and reduction. Alternatively, the method first subjects the spent catalyst to coke-burning followed by introducing sulfate ions thereinto; and then performing oxychlorination and reduction. Disclosed is still another method for regenerating a platinum-rhenium reforming catalyst, which comprises coke-burning the spent catalyst; introducing sulfur and chlorine in the catalyst by impregnation; and then drying, calcinating and reducing.

A process for regenerating catalysts that have been deactivated or poisoned during hydrogenation of biomass, sugars and polysaccharides is described, in which polymerized species that have agglomerated to catalyst surfaces can be removed by means of washing the catalyst with hot water at subcritical temperatures. A feature of the process can regenerate the catalysts in situ, which allows the process to be adapted for used in continuous throughput reactor systems. Also described is a continuous hydrogenation process that incorporated the present regeneration process.

A process for regenerating catalysts that have been deactivated or poisoned during hydrogenation of biomass, sugars and polysaccharides is described, in which polymerized species that have agglomerated to catalyst surfaces can be removed by means of washing the catalyst with hot water at subcritical temperatures. A feature of the process can regenerate the catalysts in situ, which allows the process to be adapted for used in continuous throughput reactor systems. Also described is a continuous hydrogenation process that incorporated the present regeneration process.

A process for the regeneration of a supported noble metal catalyst comprising contacting the catalyst with a liquid aqueous system at a temperature in the range of from 90 to 160 C., wherein the pH of the aqueous system is outside the range of from 6 to 8, separating the aqueous system from catalyst; and subjecting the catalyst to calcination.

A process for the regeneration of a supported noble metal catalyst comprising contacting the catalyst with a liquid aqueous system at a temperature in the range of from 90 to 160 C., wherein the pH of the aqueous system is outside the range of from 6 to 8, separating the aqueous system from catalyst; and subjecting the catalyst to calcination.

A method for regenerating a carbonyl sulfide (COS) hydrolysis catalyst for hydrolyzing COS which is contained in a gas obtained by gasifying a carbon material, wherein a spent COS hydrolysis catalyst is immersed in an acid solution for a prescribed time thereby removing poisoning substances adhering to the surface of the COS hydrolysis catalyst; and thus regenerating the COS hydrolysis catalyst.

A method for regenerating a carbonyl sulfide (COS) hydrolysis catalyst for hydrolyzing COS which is contained in a gas obtained by gasifying a carbon material, wherein a spent COS hydrolysis catalyst is immersed in an acid solution for a prescribed time thereby removing poisoning substances adhering to the surface of the COS hydrolysis catalyst; and thus regenerating the COS hydrolysis catalyst.

The following invention relates to methods for reprocessing SCR catalysts. In a first embodiment, the invention relates to a method for reprocessing SCR catalysts, wherein an oxygen-containing compound of titanium and tungsten or molybdenum is removed from the catalyst and is then reacted with a vanadium compound. In a second embodiment, the invention relates to a method for removing titanium oxide and vanadium, molybdenum, and tungsten compounds from SCR catalysts and to a method for reusing these compounds in such catalysts.

The invention refers to a process for rejuvenating a hydrotreating catalyst comprising a group VIB hydrogenation metal and/or a group VIII hydrogenation metal, which comprises the steps of: (a) regenerating the catalyst by contacting said catalyst with an oxygen containing gas at a temperature from about 300 C. to 550 C., (b) impregnating the regenerated carbon-reduced catalyst with an impregnation solution which comprises a mixture of water and a combination of MoO.sub.3 and H.sub.3PO.sub.4, (c) aging the impregnated catalyst and (d) drying the aged catalyst. The invention also refers to the rejuvenated catalyst obtained and its use for hydro-treating hydrocarbon feedstocks.

The invention refers to a process for rejuvenating a hydrotreating catalyst comprising a group VIB hydrogenation metal and/or a group VIII hydrogenation metal, which comprises the steps of: (a) regenerating the catalyst by contacting said catalyst with an oxygen containing gas at a temperature from about 300 C. to 550 C., (b) impregnating the regenerated carbon-reduced catalyst with an impregnation solution which comprises a mixture of water and a combination of MoO.sub.3 and H.sub.3PO.sub.4, (c) aging the impregnated catalyst and (d) drying the aged catalyst. The invention also refers to the rejuvenated catalyst obtained and its use for hydro-treating hydrocarbon feedstocks.