Provided are a denitration catalyst regeneration method and a denitration catalyst regeneration system, which are capable of recovering denitration performance to a high level and reducing the SO.sub.2 oxidation rate of a catalyst. A denitration catalyst regeneration method according to the present invention includes: a chemical solution cleaning step for immersing a denitration catalyst in a chemical solution containing a fluorine compound and an inorganic acid; a step for extracting the denitration catalyst from the chemical solution; and a finish washing step for washing the denitration catalyst extracted from the chemical solution with a finish cleaning solution containing an organic acid.

Provided are: a cleaning agent for a denitration catalyst; and a denitration catalyst regeneration method and a denitration catalyst regeneration system which make it possible to efficiently remove matter adhering to a surface of a catalyst and to greatly restore catalytic performance. The regeneration method includes: a prewashing step (S12) of washing a denitration catalyst with water; a liquid agent cleaning step (S14) of immersing the denitration catalyst washed with water in a liquid agent containing an inorganic acid and a fluorine compound; a step of recovering the denitration catalyst from the liquid agent; and a finish washing step (S16) of washing the denitration catalyst recovered from the liquid agent with a finish cleaning liquid which is water or sulfamic acid-containing water.

Provided are: a cleaning agent for a denitration catalyst; and a denitration catalyst regeneration method and a denitration catalyst regeneration system which make it possible to efficiently remove matter adhering to a surface of a catalyst and to greatly restore catalytic performance. The regeneration method includes: a prewashing step (S12) of washing a denitration catalyst with water; a liquid agent cleaning step (S14) of immersing the denitration catalyst washed with water in a liquid agent containing an inorganic acid and a fluorine compound; a step of recovering the denitration catalyst from the liquid agent; and a finish washing step (S16) of washing the denitration catalyst recovered from the liquid agent with a finish cleaning liquid which is water or sulfamic acid-containing water.

The present disclosure relates to a regenerated catalyst for hydrotreating heavy oil or residue oil and a preparation method thereof. More particularly, the present disclosure relates to the regenerated catalyst having excellent mechanical properties and desulfurization performance with minimal loss of active components and the method for preparing the regenerated catalyst. The regenerated catalyst can be used in place of the fresh catalyst, is excellent in economy and can reduce the environmental burden by reusing the spent catalyst to be disposed or buried.

The present disclosure relates to a regenerated catalyst for hydrotreating heavy oil or residue oil and a preparation method thereof. More particularly, the present disclosure relates to the regenerated catalyst having excellent mechanical properties and desulfurization performance with minimal loss of active components and the method for preparing the regenerated catalyst. The regenerated catalyst can be used in place of the fresh catalyst, is excellent in economy and can reduce the environmental burden by reusing the spent catalyst to be disposed or buried.

The present invention discloses a process for recovery and regeneration of rare earth metals or salts thereof used as catalyst and which is conveniently integrated within the overall flow sheets of manufacturing dialkyl carbonates. Alkyl carbamate, alcohol and a rare earth metal salt as catalyst selected from the lanthanide series are added in a reactor to afford dialkyl carbonate. The rare earth metal catalyst is selected from samarium, cerium, lanthanum, neodymium, ytterbium, europium and gadolinium. Ammonia is added to a portion of the reaction mixture to precipitate the catalyst and the separated deactivated catalyst is dissolved in acid to afford regenerated catalyst, e.g., in triflic acid in the case of samarium triflate catalyst.

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 hydrotreating 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 hydrotreating hydrocarbon feedstocks.

Provided is a process for producing hydrogen gas in a separate stream from syngas. An assembly for producing hydrogen gas in a separate stream from syngas and a method of producing hydrogen are also provided.

Provided is a process for producing hydrogen gas in a separate stream from syngas. An assembly for producing hydrogen gas in a separate stream from syngas and a method of producing hydrogen are also provided.