The present invention relates to a process for producing butadiene from ethanol, in two reaction steps, comprising a step a) of converting ethanol into acetaldehyde and a step b) of conversion into butadiene, said step b) simultaneously implementing a reaction step and a regeneration step in (n+n/2) fixed-bed reactors, n being equal to 2 or a multiple thereof, comprising a catalyst, said regeneration step comprising four successive regeneration phases, said step b) also implementing a regeneration loop for the inert gas and at least one regeneration loop for the gas streams comprising oxygen.

Disclosed herein are methods, systems, and compositions for providing catalysts for tail gas clean up in sulfur recovery operations. Aspects of the disclosure involve obtaining catalyst that was used in a first process, which is not a tailgas treating process and then using the so-obtained catalyst in a tailgas treating process. For example, the catalyst may originally be a hydroprocessing catalyst. A beneficial aspect of the disclosed methods and systems is that the re-use of spent hydroprocessing catalyst reduces hazardous waste generation by operators from spent catalyst disposal. Ultimately, this helps reduce the environmental impact of the catalyst life cycle. The disclosed methods and systems also provide an economically attractive source of high-performance catalyst for tailgas treatment, which benefits the spent catalyst generator, the catalyst provider, and the catalyst consumer.

Disclosed herein are methods, systems, and compositions for providing catalysts for tail gas clean up in sulfur recovery operations. Aspects of the disclosure involve obtaining catalyst that was used in a first process, which is not a tailgas treating process and then using the so-obtained catalyst in a tailgas treating process. For example, the catalyst may originally be a hydroprocessing catalyst. A beneficial aspect of the disclosed methods and systems is that the re-use of spent hydroprocessing catalyst reduces hazardous waste generation by operators from spent catalyst disposal. Ultimately, this helps reduce the environmental impact of the catalyst life cycle. The disclosed methods and systems also provide an economically attractive source of high-performance catalyst for tailgas treatment, which benefits the spent catalyst generator, the catalyst provider, and the catalyst consumer.

The presently disclosed subject matter relates to methods and systems for alkane dehydrogenation. In a particular non-limiting embodiment, the presently disclosed subject matter provides a system for the dehydrogenation of alkanes that includes two or more reactors configured to perform a dehydrogenation reaction of an alkane in the presence of a catalyst to produce an olefin and a catalyst regenerator, coupled to each of the two or more reactors through at least one transfer line to a regenerator, for the regeneration of spent catalyst.

The invention relates to a catalyst material comprising a support, a first metal and a second metal on said support. The first and second metals are in the form of a chemical compound. The first metal is Fe, Co or Ni, and the second metal is selected from the group consisting of Sn, Zn and In. The invention also relates to a process for the preparation of hydrogen cyanide (HCN) from methane (CH.sub.4) and ammonia (NH.sub.3), wherein the methane and ammonia are contacted with a catalyst according to the invention.

The invention relates to a catalyst material comprising a support, a first metal and a second metal on said support. The first and second metals are in the form of a chemical compound. The first metal is Fe, Co or Ni, and the second metal is selected from the group consisting of Sn, Zn and In. The invention also relates to a process for the preparation of hydrogen cyanide (HCN) from methane (CH.sub.4) and ammonia (NH.sub.3), wherein the methane and ammonia are contacted with a catalyst according to the invention.

A method of producing a regenerated hydrotreating catalyst, including a first step of preparing a hydrotreating catalyst that has been used for hydrotreatment of a petroleum fraction and has a metal element selected from Group 6 elements of the periodic table; a second step of performing regeneration treatment for part of the catalyst prepared in the first step, then performing X-ray absorption fine structure analysis for the catalyst after the regeneration treatment, and obtaining regeneration treatment conditions in which a ratio IS/IO of a peak intensity IS of a peak attributed to a bond between the metal element and a sulfur atom to a peak intensity IO of a peak attributed to a bond between the metal element and an oxygen atom is in the range of 0.1 to 0.3 in a radial distribution curve obtained from an extended X-ray absorption fine structure spectrum.

A method of producing a regenerated hydrotreating catalyst, including a first step of preparing a hydrotreating catalyst that has been used for hydrotreatment of a petroleum fraction and has a metal element selected from Group 6 elements of the periodic table; a second step of performing regeneration treatment for part of the catalyst prepared in the first step, then performing X-ray absorption fine structure analysis for the catalyst after the regeneration treatment, and obtaining regeneration treatment conditions in which a ratio IS/IO of a peak intensity IS of a peak attributed to a bond between the metal element and a sulfur atom to a peak intensity IO of a peak attributed to a bond between the metal element and an oxygen atom is in the range of 0.1 to 0.3 in a radial distribution curve obtained from an extended X-ray absorption fine structure spectrum.

A catalyst is regenerated by an inventive process using a heat exchange fluid such as superheated steam to remove heat during the process relying on efficient heat transfer (e.g., enabled by the microchannel reactor construction) in comparison with prior art heat exchange relying on a phase change, e.g. between water and (partial or complete vaporization) steam, allows simplification of the protocols to enable transition at higher temperatures between steps which translates in reduced duration of the regeneration process and avoids potential water hammering risks.

A catalyst is regenerated by an inventive process using a heat exchange fluid such as superheated steam to remove heat during the process relying on efficient heat transfer (e.g., enabled by the microchannel reactor construction) in comparison with prior art heat exchange relying on a phase change, e.g. between water and (partial or complete vaporization) steam, allows simplification of the protocols to enable transition at higher temperatures between steps which translates in reduced duration of the regeneration process and avoids potential water hammering risks.