Process for the preparation of light olefins by dehydrogenation using a catalyst comprising cerium

Abstract

Light olefins can be prepared by dehydrogenation using a catalyst. The catalyst may comprise: 0.1 wt% to 10 wt% of one or more metals selected from gallium, indium, thallium, or combinations thereof; 5 ppmw to 500 ppmw of one or more metals selected from platinum, palladium, rhodium, iridium, ruthenium, osmium, or combinations thereof; 0.01 wt% to 0.8 wt% of cerium; and at least 85 wt% of a support.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 610,035, filed on December 14, 2023, the contents of which are incorporated herein by reference. Technical Field

[0003] The embodiments described herein generally involve chemical processing, and more specifically, methods and systems for the production of light olefins. Background Technology

[0004] Light olefins, such as ethylene, butene, and propylene, can be used as base materials to produce a wide variety of materials, such as polypropylene, isopropanol, and acrylic acid, which can be used in applications such as packaging, construction, and textiles. As a result of this utility, there is a global demand for light olefins. Suitable processes for producing light olefins generally depend on the given chemical feedstock and include those utilizing fluidized bed catalysts. For example, light olefins can be formed by the catalytic dehydrogenation of alkanes in a fluidized bed reactor. However, improvements are needed in the systems and associated catalysts used to produce light olefins. Summary of the Invention

[0005] Some methods and related systems for the production of light olefins utilize supplemental fuels that are burned during the production process to heat the catalyst. For example, the catalyst can be circulated between a reactor and a burner, where light olefins are produced in an endothermic reaction in the reactor, and where the catalyst is heated in the burner by the exothermic combustion of at least one supplemental fuel (sometimes accompanied by the combustion of coke). Such catalysts advantageously possess catalytic activity not only for the dehydrogenation of alkanes to form olefins but also for the combustion of supplemental fuels. Some embodiments of such suitable catalysts include, for example, gallium and platinum on a support. In some embodiments, methane can be used in this supplemental fuel. In such embodiments, conventional catalysts for dehydrogenation may suffer from relatively low methane combustion activity, meaning that using methane as a supplemental fuel may not provide sufficient heat to raise the temperature of the catalyst to the desired temperature utilized in the dehydrogenation reaction. Furthermore, the use of conventional catalysts that may suffer from low methane combustion activity may adversely affect the safety of the dehydrogenation process, as unburned methane may exceed the low flammability levels required for the safe operation of the regenerator. As described herein, it has been found that, according to some embodiments, catalysts additionally containing cerium can enhance methane combustion while maintaining the desired dehydrogenation activity compared to conventional catalysts, such as those not containing cerium. Furthermore, as described herein, the inclusion of cerium can enhance the catalytic stability of dehydrogenation.

[0006] According to one or more embodiments of this disclosure, light olefins can be prepared by dehydrogenation, wherein the method may include contacting a hydrocarbon-containing feedstock with a catalyst in a reactor to form an olefin-containing effluent, and transferring the catalyst to a burner and heating the catalyst by burning supplemental fuel. The residence time of the catalyst in the reactor may be less than or equal to 5 minutes, and the supplemental fuel may contain more than or equal to 1 mol% methane. The method may further include transferring the catalyst from the burner to an oxygen treatment zone and exposing the catalyst to oxygen-containing gas in the oxygen treatment zone for 2 to 20 minutes, and transferring the catalyst from the oxygen treatment zone to the reactor, such that at least a portion of the catalyst is continuously circulated between the reactor, the burner, and the oxygen treatment zone. The oxygen-containing gas may contain at least 10 mol% oxygen. The catalyst may contain: 0.1 wt% to 10 wt% of one or more metals selected from gallium, indium, thallium, or combinations thereof; 5 ppmw to 500 ppmw of one or more metals selected from platinum, palladium, rhodium, iridium, ruthenium, osmium, or combinations thereof; 0.01 wt% to 0.8 wt% cerium; and at least 85 wt% of a support.

[0007] It should be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and characteristics of the claimed subject matter. Additional features and advantages of the embodiments will be set forth in the detailed description and, in part, will be readily apparent to those skilled in the art from the description, including the drawings and claims, or may be recognized by practice of the described embodiments. The drawings are included to provide a further understanding of the embodiments and, together with the detailed description, to explain the principles and operation of the claimed subject matter. However, the embodiments depicted in the drawings are illustrative and exemplary in nature and are not intended to limit the claimed subject matter. Attached Figure Description

[0008] The following specific embodiments can be better understood when read in conjunction with the accompanying drawings, wherein:

[0009] Figure 1 A reactor system according to one or more embodiments of the present disclosure is schematically depicted.

[0010] When description Figure 1 The simplified illustrative illustrations do not include numerous valves, temperature sensors, electronic controllers, etc., which are available and well known to those skilled in the art. Furthermore, they do not include accompanying components typically included in such reactor systems, such as air supplies, heat exchangers, buffer tanks, etc. However, it should be understood that these components are within the scope of this disclosure.

[0011] The various implementation schemes will now be discussed in more detail, some of which are illustrated in the accompanying drawings. Detailed Implementation

[0012] As described herein, this disclosure relates to a method for preparing light olefins via dehydrogenation, utilizing specific catalyst compositions. For example, a catalyst suitable for dehydrogenation may comprise: 0.1 wt% to 10 wt% of one or more metals selected from gallium, indium, thallium, or combinations thereof; 5 ppmw to 500 ppmw of one or more metals selected from platinum, palladium, rhodium, iridium, ruthenium, osmium, or combinations thereof; 0.01 wt% to 0.8 wt% of cerium; and at least 85 wt% of a support. In one or more embodiments, such catalysts provide dual catalytic functionality for the dehydrogenation of alkanes and the combustion of supplemental fuels. Such cerium-containing catalysts may be particularly suitable for the fluidized dehydrogenation of light alkanes to light olefins, such as propane to propylene, wherein methane is used as supplemental fuel to heat the catalyst.

[0013] This article discusses the operation of a fluidized dehydrogenation reactor system for the production of light olefins, such as propylene. Figure 1 The embodiments of the methods disclosed herein are described in detail within the context of reactor systems. However, it should be understood that the principles disclosed and taught herein can be applied to other systems utilizing different system components oriented in different ways. For example, the concepts described herein can be equivalently applied to other systems with alternative reactor and regeneration units, such as those operating under non-fluidized conditions, or those containing a feed pipe instead of a riser. It should also be understood that not all methods are applicable. Figure 1 All parts thereof should be interpreted as essential to the claimed subject matter. Furthermore, although the method steps listed in the appended claims are... Figure 1 The methods described are in the context of this document, but such enumerated steps should be understood to be applicable to other systems, as understood by those skilled in the art.

[0014] Now for reference Figure 1 An example reactor system 102 is schematically depicted that can be applied to the methods and / or apparatus described herein. Reactor system 102 typically includes multiple system components, such as reactor section 200 and catalyst handling section 300. As described herein, "system component" refers to parts of reactor system 102, such as reactors, separators, delivery lines, combinations thereof, etc. Figure 1In the context of this document, reactor section 200 generally refers to the section of reactor system 102 where the primary process reaction (e.g., dehydrogenation) occurs to form an olefin-containing effluent. Hydrocarbon-containing feed enters reactor section 200, contacts the catalyst, is converted into an olefin-containing effluent (containing products and unreacted feed), and exits reactor section 200. Reactor section 200 includes reactor 202, which may include an upstream reactor section 250 and a downstream reactor section 230. According to one or more embodiments, such as... Figure 1 As depicted, reactor section 200 may additionally include catalyst separation section 210 for separating the catalyst from the olefin-containing effluent formed in reactor 202. Additionally, as used herein, catalyst treatment section 300 generally refers to a portion of reactor system 102 in which the catalyst is treated in some way, such as by combustion, to improve catalytic activity, for example by decoking and / or heating the catalyst. Catalyst treatment section 300 may include burner 350 and riser 330, and may additionally include catalyst separation section 310. In one or more embodiments, catalyst separation section 210 may be in fluid communication with burner 350 (e.g., via riser 426), and catalyst separation section 310 may be in fluid communication with upstream reactor section 250 (e.g., via riser 424 and delivery riser 430).

[0015] As typically described in this article, Figure 1 In the illustrated embodiment, the catalyst circulates between reactor section 200 and catalyst treatment section 300. It should be understood that when referred to herein as “catalyst,” it can mean a solid material that is catalytically active to the desired reaction. The terms “catalytic activity” and “catalyst activity” refer to the degree to which a catalyst is capable of catalyzing a reaction carried out in reactor system 102. The catalyst leaving reactor section 200 may be a deactivated catalyst. As used herein, “deactivated” can mean a catalyst with reduced catalytic activity or that is colder compared to the catalyst entering reactor section 200. However, a deactivated catalyst may retain some catalytic activity. Reduced catalytic activity can be caused by contamination from substances such as coke. Coke can form on the catalyst within reactor section 200. Reactivation (sometimes referred to herein as “regeneration”) can remove contaminants such as coke, increase the temperature of the catalyst, or both. In an embodiment, a deactivated catalyst can be reactivated by catalyst reactivation in catalyst treatment section 300. Deactivated catalysts can be reactivated by, but not limited to, removal of coke by combustion, oxidation of the catalyst, other reactivation processes, or combinations thereof. In some embodiments, the catalyst may be heated during reactivation by burning supplemental fuels such as methane, ethane, propane, natural gas, or combinations thereof. The reactivated catalyst from catalyst processing section 300 is then passed back to reactor section 200.

[0016] As disclosed herein, in one or more embodiments, the supplemental fuel may include methane. For example, the supplemental fuel may include methane in an amount greater than or equal to 1 mol%, such as greater than or equal to 2 mol%, greater than or equal to 3 mol%, greater than or equal to 4 mol%, or even greater than or equal to 5 mol%. In some embodiments, the supplemental fuel includes methane in an amount not exceeding 10 mol%. In some embodiments, the supplemental fuel may include methane in an amount greater than 10 mol%, such as greater than 20 mol%, greater than 30 mol%, greater than 40 mol%, greater than 50 mol%, greater than 60 mol%, greater than 70 mol%, greater than 80 mol%, greater than 90 mol%, or even 100 mol%. Catalysts with improved methane combustion activity, such as those containing cerium as described herein, can better utilize methane as a supplemental fuel to facilitate catalyst reheating. Heating the catalyst during regeneration assists regeneration and also because the heated catalyst acts as a heat transfer agent to transport heat from burner 350 to reactor section 200 to facilitate the dehydrogenation reaction.

[0017] In a non-limiting example, the reactor system 102 described herein can be used to produce light olefins from a hydrocarbon-containing feedstock. According to one or more embodiments, the reaction can be a dehydrogenation reaction. According to such embodiments, the hydrocarbon-containing feedstock can contain one or more of ethane, propane, n-butane, and isobutane. In one or more embodiments, the hydrocarbon-containing feedstock can contain at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% of ethane. In another embodiment, the hydrocarbon-containing feedstock can contain at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% of propane. In yet another embodiment, the hydrocarbon-containing feedstock can contain at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% of n-butane. In another embodiment, the hydrocarbon feed may contain at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% of isobutane. In another embodiment, the hydrocarbon feed may contain at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% of the sum of ethane, propane, n-butane, and isobutane.

[0018] In one or more embodiments, the catalyst may comprise, substantially comprise, or comprise of: one or more of gallium, indium, or thallium; one or more of platinum, palladium, rhodium, iridium, ruthenium, or osmium; cerium; and a support. As described herein, “substantially comprise” means a material having less than 1% by weight of an unlisted material (i.e., substantially comprised of A and B means that the combination of A and B accounts for at least 99% by weight of the composition). In further embodiments, the catalyst may comprise, substantially comprise, or comprise: one or more of gallium, indium, or thallium; one or more of platinum, palladium, rhodium, iridium, ruthenium, or osmium; cerium; a support; and one or two of an alkali metal or alkaline earth metal. As described herein, the catalyst may be a solid particle suitable for fluidization.

[0019] In one or more embodiments, based on the total mass of the catalyst, the catalyst may contain one or more of gallium, indium, or thallium in an amount ranging from 0.1 wt% to 10 wt%. Such materials can catalyze the dehydrogenation of alkanes to olefins, particularly when used in combination with one or more of platinum, palladium, rhodium, iridium, ruthenium, or osmium. Such materials can also catalyze the combustion of coke and supplemental fuels. For example, the catalyst may contain one or more of gallium, indium, or thallium in amounts ranging from 0.1 wt% to 0.25 wt%, 0.25 wt% to 0.5 wt%, 0.5 wt% to 0.75 wt%, 0.75 wt% to 1 wt%, 1 wt% to 2 wt%, 2 wt% to 3 wt%, 3 wt% to 4 wt%, 4 wt% to 5 wt%, 5 wt% to 6 wt%, 6 wt% to 7 wt%, 7 wt% to 8 wt%, 8 wt% to 9 wt%, 9 wt% to 10 wt%, or any combination thereof. In some embodiments, the catalyst may contain one or more of gallium, indium, or thallium in amounts ranging from 0.1 wt% to 9 wt%, 0.1 wt% to 8 wt%, 0.1 wt% to 7 wt%, 0.1 wt% to 6 wt%, or 0.1 wt% to 5 wt%. In some embodiments, the catalyst contains only gallium but not indium or thallium, only indium but not gallium or thallium, or only thallium but not gallium or indium. It should be understood that compositional ranges describing the amounts of gallium, indium, and thallium represent ranges for any one or a combination of these materials. Without being bound by theory, it is believed that compositions having less than 0.1 wt% of one or more of gallium, indium, or thallium negatively affect the catalyst's ability to catalyze alkane dehydrogenation processes by reducing both the percentage of total dehydrogenated alkanes and the percentage of dehydrogenated alkanes as the intended product. However, it is believed that compositions having more than 10 wt% of one or more of gallium, indium, or thallium can negatively affect the catalyst's ability to catalyze alkane dehydrogenation processes, negatively affect the catalyst's selectivity to the intended product, or both.

[0020] In one or more embodiments, based on the total mass of the catalyst, the catalyst may contain one or more of platinum, palladium, rhodium, iridium, ruthenium, or osmium in amounts ranging from 5 ppmw to 500 ppmw. Such materials can catalyze the dehydrogenation of alkanes to olefins, particularly when used in combination with one or more of gallium, indium, or thallium. Such materials can also catalyze the combustion of coke and supplemental fuels. For example, the catalyst may contain one or more of platinum, palladium, rhodium, iridium, ruthenium, or osmium in amounts ranging from 5 ppmw to 50 ppmw, 50 ppmw to 100 ppmw, 100 ppmw to 200 ppmw, 200 ppmw to 300 ppmw, 300 ppmw to 400 ppmw, 400 ppmw to 500 ppmw, or any combination thereof. In some embodiments, the catalyst may contain one or more of platinum, palladium, rhodium, iridium, ruthenium, or osmium in amounts ranging from 5 ppmw to 400 ppmw, 5 ppmw to 300 ppmw, 5 ppmw to 200 ppmw, 5 ppmw to 100 ppmw, or 10 ppmw to 50 ppmw. In some embodiments, the catalyst contains only platinum but not palladium, rhodium, iridium, ruthenium, or osmium; only palladium but not platinum, rhodium, iridium, ruthenium, or osmium; only rhodium but not platinum, palladium, iridium, ruthenium, or osmium; only iridium but not platinum, palladium, rhodium, ruthenium, or osmium; only ruthenium but not platinum, palladium, rhodium, iridium, or osmium; or only osmium but not platinum, palladium, rhodium, iridium, or ruthenium. It should be understood that the compositional ranges describing the amounts of platinum, palladium, rhodium, iridium, ruthenium, and osmium represent the range of any one of these materials or combinations thereof. Unbound by theory, it is believed that combinations of one or more of platinum, palladium, rhodium, iridium, ruthenium, or osmium in amounts less than 5 ppmw negatively affect the catalyst's ability to catalyze alkane dehydrogenation processes by reducing both the percentage of total dehydrogenated alkanes and the percentage of dehydrogenated alkanes as the intended product. However, it is believed that combinations of one or more of platinum, palladium, rhodium, iridium, ruthenium, or osmium in amounts exceeding 500 ppmw can negatively affect the catalyst's ability to catalyze alkane dehydrogenation processes, negatively affect the catalyst's selectivity for the intended product, or both. Specifically, catalysts containing more than 1000 ppmw of noble metals may reduce selectivity.

[0021] In one or more embodiments, the catalyst may contain 0.01 wt% to 0.8 wt% cerium based on the total weight of the catalyst. According to some embodiments, the incorporation of cerium can promote the combustion of methane without significantly affecting the dehydrogenation of alkanes. Additionally, the inclusion of cerium can enhance the catalytic stability of dehydrogenation, ensuring that the catalytic activity does not significantly decrease during repeated cycles of dehydrogenation and heating. For example, based on the total weight of the catalyst, the catalyst may contain 0.01 wt% to 0.05 wt%, 0.05 wt% to 0.1 wt%, 0.1 wt% to 0.2 wt%, 0.2 wt% to 0.3 wt%, 0.3 wt% to 0.4 wt%, 0.4 wt% to 0.5 wt%, 0.5 wt% to 0.6 wt%, 0.6 wt% to 0.7 wt%, 0.7 wt% to 0.8 wt%, or any combination of one or more of these ranges of cerium. Without being bound by theory, it is believed that compositions containing less than 0.1 wt% cerium may not be sufficient to improve the methane combustion performance of the catalyst. In some embodiments, a cerium content greater than 0.4 wt% may promote combustion. However, compositions having a cerium content exceeding 0.8 wt% are believed to negatively affect the dehydrogenation performance of the catalyst by reducing the percentage of total dehydrogenated alkanes and / or the percentage of dehydrogenated alkanes as the intended product.

[0022] As described herein, in one or more embodiments, the catalyst may comprise a support. The support may comprise one or more of alumina, silica, or combinations thereof. For example, in some embodiments, the support may comprise one or more of alumina, silica, titanium dioxide, zirconium oxide, or combinations thereof. For example, anticipated supports include alumina, silica-containing alumina, zirconium oxide-containing alumina, titanium dioxide-containing alumina, and lanthanum-containing alumina. The support may be present in an amount of at least 85% by weight, such as at least 85% by weight, at least 90% by weight, or at least 95% by weight, relative to the total weight of the catalyst. In some embodiments, the support constitutes less than or equal to 99.5% by weight of the catalyst. Typically, the weight percentage of the support may fill the remaining portion of the entire catalyst not specified by other materials described herein.

[0023] In one or more embodiments, the catalyst may optionally contain 0.01 wt% to 5 wt% of one or more alkali metals, one or more alkaline earth metals, or both, based on the total weight of the catalyst. For example, the catalyst may contain 0.01 wt% to 0.05 wt%, 0.05 wt% to 0.1 wt%, 0.1 wt% to 0.2 wt%, 0.2 wt% to 0.3 wt%, 0.3 wt% to 0.4 wt%, 0.4 wt% to 0.5 wt%, 0.5 wt% to 0.6 wt%, 0.6 wt% to 0.7 wt%, 0.7 wt% to 0.8 wt%, 0.8 wt% to 0.9 wt%, 0.9 wt% to 1 wt%, 1 wt% to 2 wt%, 2 wt% to 3 wt%, 3 wt% to 4 wt%, 4 wt% to 5 wt%, or any combination of these ranges of one or more alkali metals, one or more alkaline earth metals, or both. In some embodiments, the catalyst may comprise 0.01 wt% to 1 wt%, 0.02 wt% to 0.75 wt%, 0.03 wt% to 0.5 wt%, 0.04 wt% to 0.4 wt%, or 0.05 wt% to 0.3 wt% of one or more alkali metals, one or more alkaline earth metals, or both. In some embodiments, one or more alkali metals or one or more alkaline earth metals may be potassium. However, compositions having more than 5 wt% of an alkali metal or alkaline earth metal are believed to reduce the dehydrogenation activity of the catalyst.

[0024] In one or more embodiments, the catalyst may comprise, consist substantially of, or consist of gallium, platinum, cerium, and a support. For example, the catalyst may comprise: 0.1 wt% to 10 wt% gallium; 5 ppmw to 500 ppmw platinum; 0.01 wt% to 0.8 wt% cerium; and at least 85 wt% support, consisting substantially of, or consist of, it. In one exemplary embodiment, the catalyst may comprise: 0.1 wt% to 5 wt% gallium; 10 ppmw to 400 ppmw platinum; 500 ppmw to 8000 ppmw cerium; and at least 85 wt% support, consisting substantially of, or consist of, it.

[0025] In one or more embodiments, the catalyst may comprise fluidizable solid particles. In some embodiments, the catalyst may exhibit properties industrially known as “Geldart A” or “Geldart B” characteristics. Catalyst types may be classified as “Group A” or “Group B”, according to D. Geldart, Gas Fluidization Technology, John Wiley & Sons (New York, 1986), pp. 34–37; and D. Geldart, Types of Gas Fluidization, Powder Technology, Vol. 7 (1973), pp. 285–292, the disclosure of which is incorporated herein by reference in its entirety.

[0026] Group A of Geldart is understood by those skilled in the art to represent aerated powders with fluidization in a bubble-free range; high bed expansion; slow and linear degassing rates; bubble characteristics that may include the advantage of splitting / re-agglomerating bubbles, with maximum bubble size and large wake; high levels of solids mixing and gas backmixing, assuming U-umf is equal (U is the velocity of the carrier gas, and Umf is the minimum fluidization velocity, typically but not necessarily measured in meters per second (m / s), i.e., where excessively high gas velocities exist); axisymmetric bulk characteristics; and no sputtering except in very shallow beds. The listed characteristics tend to improve with decreasing average particle size, assuming αp is equal; or with increasing proportions of <45 micrometers (μm); or with increasing gas pressure, temperature, viscosity, and density. Generally, the particles may exhibit small average particle size and / or low particle density (<1.4 g / cm³). 3 It is easily fluidized, exhibiting smooth fluidization at low gas velocities and controlled bubbling with small bubbles at higher gas velocities.

[0027] Geldart Group B is understood by those skilled in the art to represent “sand-like” powders that begin to bubble at Umf; exhibit moderate bed expansion; rapid degassing; no limitation on bubble size; moderate levels of solid-gas mixing and gas backmixing, assuming equal U-umf; both axisymmetric and asymmetric particles; and sputtering only in shallow beds. These properties tend to improve with decreasing average particle size, but particle size distribution and certain uncertainties in the gas, pressure, temperature, viscosity, or density appear to have little effect on improving these properties. Generally, when the density (ρp) is 1.4 < ρp < 4 g / cm³, 3 At that time, the particle size (ɗp) of most particles was 40μm < ɗp < 500μm.

[0028] In one or more embodiments, the catalyst may be prepared via initial wet impregnation (also known as dry impregnation or capillary impregnation). Such a process is described, for example, in Marceau et al., Impregnation and Drying, Synthesis of Solid Catalysts, 59 (2008), which is incorporated herein by reference in its entirety. For example, a metal precursor may be used to impregnate the support, followed by drying at a temperature below 200°C, and then calcining at a temperature below 800°C to produce the catalyst. Suitable metal precursors may include, for example, nitrate or amine nitrate metal precursors. Additionally, other suitable metal precursors are considered herein, as those skilled in the art will appreciate. In some embodiments, the method of preparing the catalyst may include impregnating the support with gallium, platinum, and cerium; drying the support; and calcining the support, wherein the catalyst comprises 0.1 wt% to 10 wt% gallium, 5 ppmw to 500 ppmw platinum, 0.01 wt% to 0.8 wt% cerium, and at least 85 wt% support.

[0029] In one or more embodiments, the catalyst can be prepared by initial wet sequential impregnation, wherein the material is impregnated in a specific order before or after drying and calcination. In initial wet sequential impregnation, the catalyst is first impregnated with one or more metal precursors, dried at a temperature below 200°C, and then calcined at a temperature below 800°C. The catalyst is then subjected to at least one additional cycle of impregnation, drying, and calcination with another metal precursor to produce the finished catalyst. In initial wet sequential impregnation, the metals added to the catalyst can be added sequentially in a continuous impregnation cycle. In one or more embodiments, the support is impregnated sequentially with gallium and platinum, and then impregnated with cerium. For some embodiments, the method of preparing the catalyst may include impregnating the support with gallium and platinum, drying the support, calcining the support, impregnating the support with cerium after drying and calcination, and drying and calcining the support after impregnation with cerium, wherein the catalyst comprises 0.1 wt% to 10 wt% gallium, 5 ppmw to 500 ppmw platinum, 0.01 wt% to 0.8 wt% cerium, and at least 85 wt% support. In another embodiment, the method of preparing the catalyst may include impregnating a support with cerium to produce a cerium-impregnated support, drying the cerium-impregnated support, calcining the cerium-impregnated support, impregnating the cerium-impregnated support with gallium and platinum after drying and calcination, and drying and calcining the cerium-impregnated support after impregnation with gallium and platinum, wherein the catalyst comprises 0.1 wt% to 10 wt% gallium, 5 ppmw to 1000 ppmw platinum, 0.01 wt% to 0.8 wt% cerium and at least 85 wt% support.

[0030] Sequential impregnation with initial wet allows the support to be impregnated with metals in a sequential order, with some metals being impregnated onto the support before others. Therefore, the impregnation order can be changed as needed. Additionally, as those skilled in the art will appreciate, other suitable methods for preparing the catalysts described herein are contemplated.

[0031] Now refer to it again Figure 1 Hydrocarbon-containing feed can enter feed inlet 434 into reactor 202, and olefin-containing effluent can exit reactor system 102 via pipe 420. According to one or more embodiments, reactor system 102 can be operated by feeding hydrocarbon-containing feed (e.g., in a feed stream) and fluidized catalyst into upstream reactor section 250. The hydrocarbon-containing feed contacts the catalyst in upstream reactor section 250, and each hydrocarbon-containing feed flows upward through downstream reactor section 230 to produce olefin-containing effluent. Reactor 202 can operate at relatively high temperatures, such as 500°C to 800°C (e.g., 500°C to 550°C, 550°C to 600°C, 600°C to 650°C, 650°C to 700°C, 700°C to 750°C, 750°C to 800°C, or any combination of one or more of these ranges).

[0032] Now for detailed reference Figure 1 The reactor section 200 may include an upstream reactor section 250, a transition section 258, and a downstream reactor section 230, such as a riser. The transition section 258 may connect the upstream reactor section 250 and the downstream reactor section 230. Figure 1 As depicted, the upstream reactor section 250 can be located below the downstream reactor section 230. This configuration can be referred to as an upflow configuration in reactor 202. The upstream reactor section 250 may include a vessel, drum, barrel, tank, or other vessel suitable for a given chemical reaction. Figure 1 As depicted, the upstream reactor section 250 can be connected to the downstream reactor section 230 via a transition section 258. The upstream reactor section 250 can typically have a larger cross-sectional area than the downstream reactor section 230. The transition section 258 can gradually taper from the cross-sectional size of the upstream reactor section 250 to the cross-sectional size of the downstream reactor section 230, such that the transition section 258 protrudes inward from the upstream reactor section 250 into the downstream reactor section 230. For example, the transition section 258 can be a frustum.

[0033] The upstream reactor section 250 can be connected to a feed riser 430, which, in operation, provides the reactivated catalyst in the feed stream to the reactor section 200. The reactivated catalyst and / or reactant chemicals can be mixed with a distributor 260 contained in the upstream reactor section 250. The catalyst entering the upstream reactor section 250 via the feed riser 430 can be transferred to the feed riser 430 via a riser 424, thereby reaching the catalyst processing section 300. In some embodiments, the catalyst can enter the feed riser 430 directly from the catalyst separation section 210 via a riser 422, wherein the catalyst enters the upstream reactor section 250, and in such embodiments, some catalyst is not transferred through the catalyst processing section 300. The catalyst can also be fed directly to the upstream reactor section 250 via a riser 422 (in... Figure 1 (Not depicted in the text). This catalyst can be slightly deactivated, but in some embodiments it may still be suitable for reaction in the upstream reactor section 250, especially when used in combination with a reactivation catalyst.

[0034] In one or more embodiments, the residence time of the catalyst in reactor section 200 may be less than or equal to 5 minutes. As used herein, the term "residence time" refers to the average amount of time that the catalyst or other specified material spends in reactor section 200. Because this residence time is an average, the amount of time that the catalyst may spend in reactor section 200 during any given cycle may not be equal to the average, but will average to approximately the residence time over time. In some embodiments, the residence time of the catalyst in reactor section 200 may be less than or equal to 4.5 minutes, less than or equal to 4 minutes, less than or equal to 3.5 minutes, less than or equal to 3 minutes, less than or equal to 2.5 minutes, less than or equal to 2 minutes, less than or equal to 1.5 minutes, less than or equal to 1 minute, less than or equal to 0.5 minutes, or less than or equal to 0.1 minutes. Without being bound by theory, it is believed that a catalyst residence time greater than 3 minutes may increase equipment costs without a matching increase in catalyst dehydrogenation performance. However, it is believed that a catalyst residence time less than 0.1 minutes may not allow the catalyst to adequately catalyze the dehydrogenation reaction.

[0035] Still referencing Figure 1 In one or more embodiments, based on the shape, size, and other processing conditions (such as temperature and pressure) in the upstream reactor section 250 and the downstream reactor section 230, the upstream reactor section 250 may operate as a fluidized bed, such as in a fast fluidized, turbulent, or bubbling bed flow reactor, while the downstream reactor section 230 may operate more in a plug flow manner, such as in a riser reactor. For example, Figure 1Reactor 202 may include an upstream reactor section 250 operating as a fast fluidized, turbulent, or bubbling bed reactor and a downstream reactor section 230 operating as a dilute-phase riser reactor, resulting in simultaneous upward movement of the average catalyst and gas flow. As used herein, the term "average flow" refers to net flow, i.e., total upward flow minus reverse or countercurrent flow, which is typically the behavior of fluidized particles. As described herein, a "fast fluidized" reactor may refer to a reactor utilizing a fluidized state in which the apparent velocity of the gas phase is greater than the choke velocity and can be semi-dense in operation. As described herein, a "turbulent" reactor may refer to a fluidized state in which the apparent velocity is less than the choke velocity and is denser than a fast fluidized state. As described herein, a "bubbling bed" reactor may refer to a fluidized state in which clearly defined bubbles exist in two clearly separated phases in a highly dense bed. "Choke velocity" refers to the minimum velocity required to maintain solids in dilute-phase mode in a vertical delivery line. As described in this article, "dilute phase riser" can refer to a riser reactor operating at the aforementioned choke velocity.

[0036] According to one or more embodiments, the olefin-containing effluent and catalyst can be transferred from the downstream reactor section 230 to a separation unit 220 in the catalyst separation section 210, where the catalyst is at least partially separated from the olefin-containing effluent, which is then conveyed out of the catalyst separation section 210. According to one or more embodiments, after the catalyst is separated from the vapor in the separation unit 220, the catalyst can typically move through a stripper 224 to the catalyst outlet port 222, whereby the catalyst is transferred from the reactor section 200 via a riser 426 and enters the catalyst processing section 300.

[0037] According to one or more embodiments, the separation device 220 may be a cyclone separation system, which may include two or more stages of cyclone separation. In embodiments where the separation device 220 includes more than one cyclone separation stage, the first separation device into which the fluidized stream enters is referred to as the primary cyclone separator. The fluidized effluent from the primary cyclone separator may enter a secondary cyclone separator for further separation. The primary cyclone separator may include, for example, a primary cyclone separator and systems commercially available under the names VSS (available from UOP), LD2 (available from Stone and Webster), and RS2 (available from Stone and Webster). Primary cyclone separators are described, for example, in U.S. Patent Nos. 4,579,716, 5,190,650, and 5,275,641, the entire contents of which are incorporated herein by reference. In some separation systems that utilize a primary cyclone separator as the primary cyclone separation unit, one or more additional cyclone separators, such as secondary and tertiary cyclone separators, are used to further separate the catalyst from the product gas. It should be understood that any primary cyclone separation unit can be used in the embodiments of this disclosure.

[0038] Still referencing Figure 1 The separated catalyst is transferred from catalyst separation section 210 to burner 350. In some embodiments, the catalyst may be exposed to another oxygen-containing gas, such as air, downstream of reactor 202 and upstream of burner 350 (e.g., in a riser leading to burner 350). This oxygen exposure can be used to oxidize the catalyst prior to combustion, which can improve combustion catalytic function.

[0039] In burner 350, the catalyst can be treated, for example, by burning coke with oxygen. For example, but not limited to, the catalyst can be decoked and / or combustible supplementary fuel to heat the catalyst. The catalyst is then passed from burner 350 and through riser 330 to riser terminal separator 378, where the gaseous and solid components from riser 330 are at least partially separated. Vapor and residual solids are conveyed to secondary separation unit 320 in catalyst separation section 310, where the remaining catalyst is separated from the gas from catalyst treatment (e.g., gas emitted from burning used catalyst or supplementary fuel, referred to herein as flue gas). Flue gas can be passed from catalyst treatment section 300 via outlet pipe 432. The separated catalyst is then passed via riser 424 and conveyor riser 430 through oxygen treatment zone 370 within catalyst separation section 310 to upstream reactor section 250, where the catalyst is further used for catalytic reaction. Thus, the catalyst can be circulated between reactor section 200 and catalyst treatment section 300 during operation. Generally, the processed chemical stream containing hydrocarbon feed and olefin effluent can be gaseous, and the catalyst can be a fluidized particulate solid.

[0040] Now referencing the catalyst treatment section 300, such as Figure 1 As depicted, the burner 350 of the catalyst treatment section 300 may include one or more lower reactor section inlet ports 352 and may be in fluid communication with a riser 330. Oxygen-containing gas (such as air) may be supplied to the burner 350 through a pipe 428. Generally, the oxygen-containing gas may contain at least 10 mol% oxygen. The burner 350 may be in fluid communication with the catalyst separation section 210 via a riser 426, which may supply spent catalyst from the reactor section 200 to the catalyst treatment section 300 for regeneration. The burner 350 and the riser 330 (collectively referred to as the catalyst combustion reactor 302) may operate with similar or identical fluidization schemes as disclosed with respect to the upstream reactor section 250 and the downstream reactor section 230 of the reactor section 200. That is, the burner 350 may operate as a fluidized bed, such as in a fast fluidized, turbulent, or bubbling bed reactor, while the riser 330 may operate in a more plug flow manner, such as in a riser reactor. The geometry described for the upstream reactor section 250 and the downstream reactor section 230 is equally applicable to the burner 350 and the riser 330. Additionally, the burner 350 may include a fuel inlet 354 that supplies fuel, such as a hydrocarbon stream, to the burner 350.

[0041] As described herein, the catalyst can be heated in the catalyst treatment section 300 by combustion of supplemental fuel. The supplemental fuel can be burned with oxygen and supplemental fuel to heat the catalyst; supplemental fuels include hydrogen, methane, ethane, propane, natural gas, or combinations thereof. Without being bound by any theory, when methane is used as supplemental fuel, a cerium-containing catalyst, as described herein, better catalyzes the combustion of methane to heat the catalyst. When methane is used as supplemental fuel, a cerium-free catalyst may be defective because it does not promote the heating of the catalyst to the temperature required for dehydrogenation.

[0042] As described in one or more embodiments, after separating the catalyst from the flue gas in riser terminal separator 378 and secondary separation unit 320, the treated catalyst is treated with an oxygen-containing gas (such as air) in oxygen treatment zone 370. Typically, the oxygen-containing gas in oxygen treatment zone 370 may contain at least 10 mol% oxygen and is substantially free of combustible gaseous hydrocarbons present in burner 350. In some embodiments, oxygen treatment zone 370 includes a fluid-solids contact device. The fluid-solids contact device may include baffles or grid structures to facilitate contact between the treated catalyst and the oxygen-containing gas. Examples of fluid-solids contact devices are further described in detail in U.S. Patents 9,827,543 and 9,815,040. The fluidization scheme within the oxygen treatment zone may be a bubbling bed type fluidization. Oxygen treatment zone 370 may include an oxygen-containing gas inlet 372 that supplies oxygen-containing gas to oxygen treatment zone 370 for oxygen treatment of the catalyst.

[0043] As disclosed herein, in one or more embodiments, the catalyst may be exposed to oxygen-containing gas in the oxygen treatment zone 370. For example, the catalyst may be exposed to oxygen-containing gas for 2 to 20 minutes, such as 2 to 4 minutes, 4 to 6 minutes, 6 to 8 minutes, 8 to 10 minutes, 10 to 12 minutes, 12 to 14 minutes, 14 to 16 minutes, 16 to 18 minutes, 18 to 20 minutes, or any combination of these ranges. In some embodiments, the catalyst may be exposed to oxygen-containing gas for 4 to 18 minutes, 6 to 17 minutes, 8 to 16 minutes, or 10 to 15 minutes. Without being bound by theory, it is believed that exposing the catalyst to oxygen-containing gas for more than 20 minutes may increase equipment costs without a matching increase in catalyst regeneration efficiency. However, it is believed that exposure to oxygen-containing gas for less than 2 minutes may result in less efficient catalyst regeneration, which may reduce the catalyst's dehydrogenation activity.

[0044] In one or more embodiments, the catalyst may be exposed to oxygen-containing gas at a temperature of at least 650°C, such as 650°C to 800°C. Without being bound by any particular theory, it is believed that regeneration at a temperature of at least 650°C may be most efficient when the catalyst is supported on cerium, according to the embodiments described herein.

[0045] In one or more embodiments, light olefins may be present in and comprise a "product stream," sometimes referred to as an "olefin-containing effluent." This stream exits... Figure 1 The reactor system can then be used for further processing. As used in this disclosure, the term "light olefins" refers to one or more of ethylene, propylene, and butene. The term "butene" includes any butene isomer, such as α-butene, cis-β-butene, trans-β-butene, and isobutene. In some embodiments, the olefin-containing effluent contains at least 25% by weight of light olefins based on the total weight of the olefin-containing effluent. For example, the olefin-containing effluent may contain at least 35% by weight, at least 45% by weight of light olefins, at least 55% by weight of light olefins, at least 65% by weight of light olefins, or at least 75% by weight of light olefins based on the total weight of the olefin-containing effluent. The olefin-containing effluent may also contain unreacted components of the hydrocarbon-containing effluent and other reaction products that are not considered light olefins. The light olefins can be separated from the unreacted components in subsequent separation steps.

[0046] Example

[0047] Various embodiments of this disclosure will be further illustrated by the following examples. These examples are illustrative in nature and should not be construed as limiting the subject matter of this disclosure.

[0048] Example 1 - Effect of Cerium Loading

[0049] In Example 1, five different catalytically active particle (i.e., catalyst) samples were prepared, and the effect of cerium loading on the catalysts was observed at reactivation times of 2 minutes and 15 minutes. For the purposes of Example 1, the samples were prepared as follows: first, microspherical alumina supports were prepared by spray drying a mixture of hydrated alumina and Ludox silica (available from WRGrace); then, the resulting spray-dried particles were heated at a temperature sufficient to obtain particle sizes ranging from 5 µm to 300 µm, pore volumes of 0.20 mL / g ± 0.10 mL / g, and surface areas of 70 m². 2 / g±20m 2 / g of particles with a silica content of 2.5 wt% ± 2.5 wt%. The catalyst material was prepared using a wet impregnation method, in which one or more specified metals were loaded onto a support using a nitrate or amine nitrate metal precursor, followed by drying at a temperature below 200°C and then calcining at a temperature below 800°C.

[0050] Prior to performance evaluation, all catalyst samples from Example 1 were aged at 800°C for five days in an air-purged furnace to degrade the samples. Samples were prepared by mixing 0.5 g of thermally aged catalyst with 1.0 g of inert silicon carbide and loading the samples into a quartz reactor.

[0051] The sample was conditioned by first undergoing 10 interrupted cycles, which was carried out in two steps: a reaction step, in which the dehydrogenation process was carried out at 625°C for 10 hours. -1 The reaction was carried out for 60 seconds with a propane heavy hourly space velocity (WHSV) and a feed composition of 90% propane / 10% nitrogen; followed by a reactivation step, in which the catalyst was heated at 730°C for 5 minutes in 100% dry air at a flow rate of 49.4 standard cubic centimeters per minute (sccm). The sample was tested in a dehydrogenation and regeneration test cycle after 10 interrupted cycles. The dehydrogenation and regeneration test cycle was run in three steps: reaction, combustion, and reactivation. The reaction step was carried out under the same conditions as the interrupted cycle reaction step, and dehydrogenation performance data were collected after 30 seconds of operation. The combustion step was carried out at 730°C with 2.5 mol% methane and equilibrium air at a total flow rate of 49.4 sccm for 0.1 hr. -1 The methane WHSV was subjected to combustion for 3 minutes. Combustion data were collected after 80 seconds of operation. The reactivation step was performed by heating the sample at 730°C in 100% dry air at a flow rate of 49.4 sccm for 2 or 15 minutes, as indicated in Table 1. The reactor system was purged with inert gas between the reaction, combustion, and reactivation steps. The dehydrogenation and combustion performance of the sample after 25 cycles is reported in Table 1.

[0052]

[0053] As indicated in Table 1, all samples containing cerium (i.e., samples 1–4) showed improved methane conversion, which is generally expected. Additionally, the addition of cerium in amounts up to 0.8 wt% resulted in increased propane conversion and propylene selectivity compared to sample A without cerium. However, once cerium was added in amounts greater than 0.8 wt%, propane conversion and propylene selectivity decreased. For example, the sample containing 1.0 wt% cerium showed decreased propane conversion at reactivation times of 2 min and 15 min compared to the sample without cerium (i.e., propane conversion decreased from 40.1% to 38.4% and from 41.3% to 4.1% in the corresponding tests).

[0054] Example 2 - Effects of High-Severity Testing

[0055] In Example 2, five catalyst samples were prepared, and the effect of high-severity conditions was observed. The samples were prepared by heat treatment at 750°C for three days in a static oven. For testing, 0.1 g of catalyst was loaded into a U-shaped fused silica tube to form a catalyst bed. The quartz tube had an inlet with an internal dimension of 3 mm and an outlet with an internal dimension of 0.8 mm. To load the reactor, a small amount of quartz wool was first packed at the bottom of the inlet. Then, quartz fragments with a particle size of 0.5 mm to 1 mm were loaded on top of the catalyst bed. Finally, quartz wool was packed on top of the quartz fragments to secure the material. The performance of the samples was calculated after 50 cycles and measured at 25 seconds of dehydrogenation operation and 50 seconds of combustion operation.

[0056] The dehydrogenation and regeneration test cycle was run through three steps: reaction, combustion, and reactivation. The reaction step was carried out by a dehydrogenation process at 625 °C for 60 seconds, with a propane weight hourly space velocity (WHSV) of 50 hr. -1 The feed composition was 90% propane / 10% nitrogen. Combustion was performed at 730°C with 2.5 mol% methane / equilibrium air at a total flow rate of 49.4 sccm for 50 hours. -1 The methane WHSV was reacted for 3 minutes. The reactivation step was performed by heating the sample at 730 °C in 100% dry air at a flow rate of 49.4 sccm for 15 minutes. Between the reaction, combustion, and reactivation steps, the reactor system was purged with an inert gas. The dehydrogenation and combustion performance of the sample after 50 cycles is reported in Table 2.

[0057] The main difference between Example 1 and Example 2 is the heavy hourly space velocity (WHSV) of propane. The method in Example 1 uses a WHSV of 10 hr for propane. -1 The following occurs, and the method of Example 2 is performed with a WHSV of 50 hr for propane. -1 This will happen.

[0058]

[0059] Table 2 shows that the presence of cerium increases the deactivation slope of the reaction, thereby improving the catalytic activity of the samples. The deactivation slope of the samples under dehydrogenation conditions is calculated as the change in methane combustion activity over time. Furthermore, for all cerium-containing samples (i.e., samples 5-8), methane conversion is increased, which is generally desirable. Propane conversion is also increased for samples with cerium levels between 0.3 wt% and 0.8 wt% (i.e., samples 5-7) compared to sample B, which does not contain cerium. Similar to Example 1, adding cerium in amounts greater than 0.8 wt% results in a reduction in propane. For example, sample B has a propane conversion of 29.0%, and sample 8, with 1.0 wt% cerium added, has a propane conversion of 26.9%. Therefore, in some embodiments, a cerium level of 0.8 wt% or less is desirable to maintain good propane conversion.

[0060] Example 3 - Effects of Regeneration Conditions

[0061] In Example 3, five catalyst samples were prepared, and the effects of regeneration conditions on dehydrogenation and combustion performance were investigated. The samples in Example 3 were prepared using the catalyst preparation procedure of Example 1. The conditions were the same as in Example 1, as shown in Table 3, with minor adjustments to the regeneration temperature and reactivation time. Except for the regeneration temperature and reactivation time, the test conditions were the same as in Example 1, as indicated in Table 3.

[0062]

[0063] Table 3 shows that adding cerium at the reactivation temperature of 630 °C did not improve propane conversion (i.e., samples C and 9). Furthermore, only a slight increase in methane conversion was observed at 630 °C, but the conversion rates for both samples were very low, which is undesirable and potentially dangerous during operation. For example, sample C had a propane conversion of 43.8% and a methane conversion of 15.2%, compared to sample 9 with 0.3 wt% Ce, which had a propane conversion of 43.7% and a methane conversion of 18.3%. The large amount of unconverted methane present during reactivation at 630 °C could exceed the flammability threshold of the reaction and lead to potential safety issues. Therefore, catalyst regeneration at 630 °C is detrimental to some dehydrogenation processes that rely on the heat generated by the combustion of methane-containing fuel gases.

[0064] In contrast, Table 3 shows a significant increase in methane conversion at 730 °C. Furthermore, the presence of cerium improves methane conversion (i.e., samples 10 and 11). However, as in Examples 1 and 2, the presence of 1.0 wt% cerium in the catalyst has an adverse effect on propane conversion. The propane conversion of sample D without added cerium was 48.5%, while that of sample 11 with added 1.0 wt% cerium was 40.0%. This reduction in dehydrogenation performance is undesirable; therefore, catalysts with 1.0 wt% or more cerium are disadvantageous. A cerium level of 0.8 wt% or less is required to maintain good dehydrogenation performance while improving fuel gas combustion.

[0065] This disclosure includes many aspects, including aspects 1 through 15 described herein.

[0066] Aspect 1. A method for preparing light olefins by dehydrogenation, the method comprising: contacting a hydrocarbon-containing feedstock with a catalyst in a reactor to form an olefin-containing effluent, wherein the residence time of the catalyst in the reactor is less than or equal to 5 minutes; transferring the catalyst to a burner and heating the catalyst by burning supplemental fuel, wherein the supplemental fuel contains greater than or equal to 1 mol% methane; transferring the catalyst from the burner to an oxygen treatment zone and exposing the catalyst in the oxygen treatment zone to oxygen-containing gas for 2 minutes to 20 minutes, wherein the hydrocarbon-containing feedstock contains greater than or equal to 1 mol% methane; and transferring the catalyst from the burner to an oxygen treatment zone and exposing the catalyst to oxygen-containing gas for 2 minutes to 20 minutes in the oxygen treatment zone, wherein the hydrocarbon-containing feedstock contains greater than or equal to 1 mol% methane; ... The oxygen gas comprises at least 10 mol% oxygen; and the catalyst is transferred from the oxygen treatment zone to the reactor such that at least a portion of the catalyst is continuously circulated between the reactor, the burner, and the oxygen treatment zone; wherein the catalyst comprises: 0.1 wt% to 10 wt% of one or more metals selected from gallium, indium, thallium, or combinations thereof; 5 ppmw to 500 ppmw of one or more metals selected from platinum, palladium, rhodium, iridium, ruthenium, osmium, or combinations thereof; 0.01 wt% to 0.8 wt% cerium; and at least 85 wt% of a support.

[0067] Aspect 2. The method according to any one of the preceding aspects, wherein the catalyst further comprises 0.01% to 5% by weight of one or more alkali metals or alkaline earth metals.

[0068] Aspect 3. The method according to any of the foregoing aspects, the method further comprising at least partially separating the olefin-containing effluent from the catalyst.

[0069] Aspect 4. The method according to any one of the preceding aspects, wherein the supplementary fuel contains at least 3 mol% methane.

[0070] Aspect 5. The method according to any one of the preceding aspects, wherein the residence time of the catalyst in the reactor is less than or equal to 3 minutes.

[0071] Aspect 6. The method according to any one of the preceding aspects, wherein the residence time of the catalyst in the reactor is less than or equal to 1 minute.

[0072] Aspect 7. The method according to any of the preceding aspects, the method further comprising exposing the catalyst to another oxygen-containing gas downstream of the reactor and upstream of the burner.

[0073] Aspect 8. The method according to any one of the preceding aspects, wherein the carrier comprises alumina, silicon dioxide, titanium dioxide, zirconium oxide, or a combination thereof.

[0074] Aspect 9. The method according to any one of the preceding aspects, wherein the catalyst has Geldart Group A or Geldart Group B characteristics.

[0075] Aspect 10. The method according to any one of the preceding aspects, wherein the hydrocarbon feed comprises propane and the olefin effluent comprises propylene.

[0076] Aspect 11. The method according to any one of the preceding aspects, wherein the catalyst comprises: 0.1 wt% to 10 wt% gallium; and 5 ppmw to 500 ppmw platinum.

[0077] Aspect 12. The method according to any one of the preceding aspects, wherein the catalyst comprises: 0.1 wt% to 5 wt% gallium; 10 ppmw to 400 ppmw platinum; and 0.01 wt% to 0.8 wt% cerium.

[0078] Aspect 13. The method according to any one of the preceding aspects, wherein the reactor is operated at a temperature of 500°C to 800°C.

[0079] Aspect 14. The method according to any one of the preceding aspects, wherein the oxygen-containing gas is air.

[0080] Aspect 15. The method according to any one of the preceding aspects, wherein the catalyst is exposed to the oxygen-containing gas at a temperature of 650°C to 800°C.

[0081] It will be apparent to those skilled in the art that various modifications and variations can be made to the technology disclosed herein without departing from the spirit and scope of this invention. Because modifications, combinations, sub-combinations, and variations of the disclosed embodiments can be made by those skilled in the art that incorporate the spirit and essence of the technology disclosed herein, this technology should be construed as including all things within the scope of the appended claims and their equivalents. Furthermore, although some aspects of this disclosure may be identified herein as advantageous or particularly advantageous, this disclosure is not limited to these aspects upon consideration.

[0082] It should be noted that the various details described in this disclosure should not be construed as implying that such details relate to elements that are fundamental components of the various embodiments described in this disclosure, even where specific elements are shown in each of the accompanying drawings. Unless so expressly stated, none of the features disclosed and described herein should be interpreted as "essential." The embodiments considered in this art include those that include some or all of the features of the appended claims.

[0083] For the purposes of describing and defining this disclosure, it should be noted that the term "about" is used in this disclosure to indicate an inherent uncertainty attributable to any quantitative comparison, value, measurement, or other representation. The term "about" is also used in this disclosure to indicate the degree to which a quantitative representation may vary from a specified reference without causing a change in the essential function of the subject matter of interest.

[0084] In relevant contexts, where a composition is described as "comprising" one or more elements, embodiments of compositions "composed of" or "substantially composed of" those one or more elements are considered herein.

[0085] It should be understood that, in some embodiments, the composition range of a chemical component in a stream or reactor should be understood as a mixture containing isomers of that component. For example, specifying the composition range of butene may include a mixture of various isomers of butene. It should be understood that the embodiments provide composition ranges for various streams, and the total amount of isomers of a particular chemical composition may constitute a range.

[0086] It should be noted that one or more of the following claims and detailed descriptions utilize the terms "where" or "wherein" as transitional phrases. For the purpose of defining this technology, it should be noted that this term is introduced in the claims as an open transitional phrase used to introduce a description of a series of characteristics of the structure, and should be interpreted in a manner similar to the more commonly used open prepositional term "comprising".

[0087] It should be understood that any two quantitative values ​​assigned to a characteristic can constitute a range for that characteristic, and all combinations of ranges formed by all stated quantitative values ​​of a given characteristic are considered in this disclosure. Where multiple ranges of quantitative values ​​are provided, these ranges can be combined to form a wider range, as is considered in the embodiments described herein.

Claims

1. A method for preparing light olefins by dehydrogenation, the method comprising: The hydrocarbon feed is brought into contact with the catalyst in the reactor to form an olefin-containing effluent, wherein the residence time of the catalyst in the reactor is less than or equal to 5 minutes; The catalyst is passed to a burner and heated by burning supplemental fuel, wherein the supplemental fuel contains more than or equal to 1 mol% methane; The catalyst is transferred from the burner to an oxygen treatment zone and exposed to oxygen-containing gas for 2 to 20 minutes in the oxygen treatment zone, wherein the oxygen-containing gas contains at least 10 mol% oxygen. as well as The catalyst is transferred from the oxygen treatment zone to the reactor such that at least a portion of the catalyst is continuously circulated between the reactor, the burner, and the oxygen treatment zone; The catalyst comprises: 0.1% to 10% by weight of one or more metals selected from gallium, indium, thallium, or combinations thereof; One or more metals selected from platinum, palladium, rhodium, iridium, ruthenium, osmium, or combinations thereof, ranging from 5 ppmw to 500 ppmw; 0.01% to 0.8% by weight of cerium; and at least 85% by weight of the carrier.

2. The method according to claim 1, wherein the catalyst further comprises 0.01% to 5% by weight of one or more alkali metals or alkaline earth metals.

3. The method according to any of the preceding claims, further comprising at least partially separating the olefin-containing effluent from the catalyst.

4. The method according to any one of the preceding claims, wherein the supplementary fuel contains at least 3 mol% methane.

5. The method according to any one of the preceding claims, wherein the residence time of the catalyst in the reactor is less than or equal to 3 minutes.

6. The method according to any one of the preceding claims, wherein the residence time of the catalyst in the reactor is less than or equal to 1 minute.

7. The method according to any of the preceding claims, the method further comprising exposing the catalyst to another oxygen-containing gas downstream of the reactor and upstream of the burner.

8. The method according to any one of the preceding claims, wherein the carrier comprises alumina, silicon dioxide, titanium dioxide, zirconium oxide, or a combination thereof.

9. The method according to any one of the preceding claims, wherein the catalyst has Geldart Group A or Geldart Group B characteristics.

10. The method according to any one of the preceding claims, wherein the hydrocarbon feed comprises propane and the olefin effluent comprises propylene.

11. The method according to any one of the preceding claims, wherein the catalyst comprises: Gallium from 0.1 wt% to 10 wt%; and Platinum from 5 ppmw to 500 ppmw.

12. The method according to any one of claims 1 to 10, wherein the catalyst comprises: Gallium from 0.1 wt% to 5 wt%; Platinum from 10 ppmw to 400 ppmw; and Cerium, ranging from 0.01% to 0.8% by weight.

13. The method according to any one of the preceding claims, wherein the reactor is operated at a temperature of 500°C to 800°C.

14. The method according to any one of the preceding claims, wherein the oxygen-containing gas is air.

15. The method according to any one of the preceding claims, wherein the catalyst is exposed to the oxygen-containing gas at a temperature of 650°C to 800°C.

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