A method includes at least two-stage process for the oligomerization of short-chain olefins in the presence of a catalyst, wherein the regeneration of the catalyst is stage-customized.

The present disclosure provides enhanced zeolites and methods of making and using same.

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.

A paraffin having 2-8 carbon atoms may be dehydrogenated by contacting the paraffin with metal oxide catalyst(s) to produce light olefins, such as propylene, under certain reaction conditions in a riser, fluidized bed, or fixed-bed swing reactor. The resulting metal oxide catalyst fines contained in the reactor effluent stream formed by the dehydrogenation reaction may be recovered by contacting the reactor effluent stream with a wash fluid to form a catalyst effluent stream that is subsequently slurried and filtered to capture the catalyst fines for potential reuse.

A paraffin having 2-8 carbon atoms may be dehydrogenated by contacting the paraffin with metal oxide catalyst(s) to produce light olefins, such as propylene, under certain reaction conditions in a riser, fluidized bed, or fixed-bed swing reactor. The resulting metal oxide catalyst fines contained in the reactor effluent stream formed by the dehydrogenation reaction may be recovered by contacting the reactor effluent stream with a wash fluid to form a catalyst effluent stream that is subsequently slurried and filtered to capture the catalyst fines for potential reuse.

There is provided a method for recycling a catalyst that exhibits a high denitration efficiency at a relatively low temperature and does not cause oxidation of SO.sub.2 in a selective catalytic reduction reaction that uses ammonia as a reducing agent. A method for recycling a denitration catalyst includes a step of spraying an aqueous solution with a pH of 7 or more onto a used denitration catalyst while the denitration catalyst is set in a denitration device to remove a surface of the denitration catalyst. The denitration catalyst contains 43 wt % or more of vanadium pentoxide and has a BET specific surface area of 30 m.sup.2/g or more. The denitration catalyst after recycling is used for denitration at 200 C. or lower.

There is provided a catalyst that exhibits a high denitration efficiency at a relatively low temperature and does not cause oxidation of SO.sub.2 in a selective catalytic reduction reaction that uses ammonia as a reducing agent. A denitration catalyst is obtained by coating a substrate with a catalyst component. The catalyst component contains 43 wt % or more of vanadium pentoxide and has a BET specific surface area of 30 m.sup.2/g or more. The denitration catalyst is used for denitration at 200 C. or lower.

There is provided a method for recycling a catalyst that exhibits a high denitration efficiency at a relatively low temperature and does not cause oxidation of SO.sub.2 in a selective catalytic reduction reaction that uses ammonia as a reducing agent. A method for recycling a denitration catalyst includes a step of removing a used denitration catalyst from a denitration device and then coating the used denitration catalyst with a catalyst component. The catalyst component contains 43 wt % or more of vanadium pentoxide and has a BET specific surface area of 30 m.sup.2/g or more, and the denitration catalyst after recycling is used for denitration at 200 C. or lower.

Multi-reactor systems with aromatization reactor vessels containing a catalyst with low surface area and pore volume, followed in series by aromatization reactor vessels containing a catalyst with high surface area and pore volume, are disclosed. Related reforming methods using the different aromatization catalysts also are described.

Multi-reactor systems with aromatization reactor vessels containing a catalyst with low surface area and pore volume, followed in series by aromatization reactor vessels containing a catalyst with high surface area and pore volume, are disclosed. Related reforming methods using the different aromatization catalysts also are described.