Catalytic activity of a spent precious metal-iron catalyst is restored by combining the spent catalyst with an iron (III) compound. This can be performed by adding the iron (III) compound into a chemical reaction that contains the spent precious metal-iron catalyst. It is unnecessary to add more of the precious metal. The process is especially useful in a continuous process for converting a nitro compound such as nitrobenzene to the corresponding amine.

Catalytic activity of a spent precious metal-iron catalyst is restored by combining the spent catalyst with an iron (III) compound. This can be performed by adding the iron (III) compound into a chemical reaction that contains the spent precious metal-iron catalyst. It is unnecessary to add more of the precious metal. The process is especially useful in a continuous process for converting a nitro compound such as nitrobenzene to the corresponding amine.

The invention provides a process for regenerating a catalyst used for the ring hydrogenation of an aromatic species, especially an aromatic ester, wherein a gas stream containing a particular amount of oxygen is used for the regeneration.

A process for preventing hazardous conditions at startup and shutdown of a reactor by sending an inert gas such as nitrogen to strip entrained oxygen from the catalyst when reactor temperatures are below about 240° C. During normal operation the entrained oxygen reacts with hydrocarbons to produce oxides but at the lower temperatures that are present at startup or shutdown these reactions do not occur sufficiently leaving oxygen that can cause hazardous conditions as temperatures increase upon startup. When the temperature is in the safe operating zone above 240° C., the nitrogen gas is stripped by air or other oxygen containing gas.

Processes and apparatuses for regenerating catalysts used in a hydrocarbon conversion process. The catalyst is separated into a bypass portion and an adsorption portion. The bypass portion is passed to a regeneration zone where coke may be removed. A vent gas from the regeneration zone may include an active additive from the catalyst, like a halogen. The vent gas is sent to an adsorption zone which also receives the adsorption portion. In the adsorption zone, the catalyst will contact and adsorb the active additive and then pass to the regeneration zone. The amount of active additive in the vent gas from the regeneration zone and the adsorption zone is reduced.

The present disclosure is directed to a non-destructive process for removing metals, metal ions and metal oxides in alumina-based materials without destroying alumina, allowing the regeneration of alumina-based catalysts. The non-destructive process uses an extracting agent that sequesters metals, metal ions and/or metal oxides present in alumina-based materials without destroying the alumina, allowing the regeneration of alumina-based catalysts.

Described is a catalyst for preparing hydrogen peroxide by an anthraquinone process and for regenerating a working solution and a method of preparing the catalyst. The catalyst contains palladium, magnesium, and cerium components uniformly distributed in alumina. Alternatively, the catalyst contains a palladium component distributed in a ring shape in an alumina sphere and magnesium and cerium components uniformly distributed in the alumina.

The present disclosure is to provide a catalyst for olefin production which is eco-friendly and has excellent conversion rates and selectivity and a preparation method thereof, and the catalyst for olefin production according to the present disclosure is one in which cobalt and zinc are supported with alumina. Particularly, the catalyst according to the present disclosure uses an amount of platinum that is about 400 times smaller than that of the conventional catalysts, and has high conversion rates and selectivity under conditions in which continuous reaction-regeneration process is possible without an additional hydrogen reduction process.

The present disclosure provides methods for producing a regenerated hydrogenation catalyst from a fouled hydrogenation catalyst having a total surface area and at least one associated impurity. The method can include maintaining contact between the fouled hydrogenation catalyst and a flushing medium that comprises water, oxygen, and an inert or diluent gas at a regeneration temperature and a regeneration pressure sufficient to remove at least a portion of the at least one impurity from the hydrogenation catalyst to produce the regenerated hydrogenation catalyst, where the regenerated hydrogenation catalyst is characterized as retaining at least 70% of the activity of the hydrogenation catalyst.

The present disclosure provides methods for producing a regenerated hydrogenation catalyst from a fouled hydrogenation catalyst having a total surface area and at least one associated impurity. The method can include maintaining contact between the fouled hydrogenation catalyst and a flushing medium that comprises water, oxygen, and an inert or diluent gas at a regeneration temperature and a regeneration pressure sufficient to remove at least a portion of the at least one impurity from the hydrogenation catalyst to produce the regenerated hydrogenation catalyst, where the regenerated hydrogenation catalyst is characterized as retaining at least 70% of the activity of the hydrogenation catalyst.