Process for forming dehydrogenation products utilizing combustion bypass of certain catalysts - Patent Application 20070122999

Abstract

The dehydrogenation product may be formed by a method including reacting a feed stream in the presence of a catalyst by a dehydrogenation reaction in a reactor to form a dehydrogenation product, separating at least a portion of the product stream from the catalyst, separating the catalyst into at least a first catalyst portion and a second catalyst portion, and sending the first catalyst portion to a combustor. The first catalyst portion may be heated in the combustor by combustion of a supplemental fuel. The method may further include passing the first catalyst portion out of the combustor and combining the first catalyst portion with a second catalyst portion downstream of the combustor to form a recombined catalyst stream, such that the second catalyst portion bypasses the combustor. The method may further include passing the recombined catalyst stream through an oxygen treatment zone and passing the recombined catalyst stream to a reactor.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 428,520, filed November 29, 2022, the entire disclosure of which is incorporated herein by reference.

[0002] FIELD OF THE INVENTION FIELD OF THE INVENTION Embodiments described herein relate generally to chemical processing, and more particularly to methods and systems for producing light olefin products. [Background technology]

[0003] Light olefins such as propylene can be used as a base material to produce many different materials, such as polypropylene, which can be used in 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 a given chemical feedstock and include those that utilize fluidized catalysts. For example, light olefins can be formed by catalytic dehydrogenation of alkanes. However, there is a need for improvement in the systems used to produce the dehydrogenated products. Summary of the Invention

[0004] Olefin products can be produced by catalytic dehydrogenation, in which a catalyst is cycled between a reactor (where the dehydrogenation reaction occurs) and a combustor (where the catalyst is heated by combustion of an auxiliary fuel) and then exposed to oxygen in an oxygen treatment zone. According to embodiments described herein, a portion of the catalyst can bypass the combustor and recombine downstream of the combustor and upstream of the oxygen treatment zone with a portion of the catalyst sent to the combustor. Such a process can be beneficial by improving catalyst life cycle time and reducing catalyst deactivation that can occur when exposed to combustion of an auxiliary fuel in the combustor.

[0005] According to one or more embodiments of the present disclosure, the dehydrogenation product may be formed by a method including reacting a feed stream in the presence of a catalyst via a dehydrogenation reaction in a reactor to form a dehydrogenation product, separating at least a portion of the product stream from the catalyst, separating the catalyst into at least a first catalyst portion and a second catalyst portion, and sending the first catalyst portion to a combustor. The first catalyst portion may be heated in the combustor by combustion of an auxiliary fuel. The method may further include passing the first catalyst portion out of the combustor and combining the first catalyst portion with a second catalyst portion downstream of the combustor to form a recombined catalyst stream, such that the second catalyst portion bypasses the combustor. The method may further include passing the recombined catalyst stream through an oxygen treatment zone and passing the recombined catalyst stream through a reactor.

[0006] 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 features of the claimed subject matter. Additional features and advantages of the embodiments are set forth in the detailed description, and in part will become readily apparent to those skilled in the art from that description, including the accompanying drawings and claims, or can be learned by practicing the described embodiments. The drawings are included to provide a further understanding of the embodiments and, together with the detailed description, serve to explain the principles and operation of the claimed subject matter. However, the embodiments shown in the drawings are illustrative and exemplary in nature and are not intended to limit the claimed subject matter. [Brief explanation of the drawings]

[0007] The following detailed description can be better understood when read in conjunction with the following drawings. [Figure 1] 1 illustrates a schematic diagram of a reactor system according to one or more embodiments of the present disclosure. [Figure 2] 1 shows experimental data described herein. [Figure 3] 1 presents additional experimental data as described herein.

[0008] 1, the numerous valves, temperature sensors, electronic controllers, etc. that may be used and known to those skilled in the art are not included. Additionally, accompanying components that are often included within such reactor systems, such as air supplies, heat exchangers, surge tanks, etc., are not included. However, it should be understood that these components are within the scope of the present disclosure.

[0009] Reference will now be made in more detail to various embodiments, some of which are illustrated in the accompanying drawings. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present disclosure relates to methods and systems for producing chemical products, such as light olefins, by dehydrogenation, as described herein. Embodiments of the present disclosure may utilize a reactor system including a reactor (where the dehydrogenation reaction occurs) and a combustor (where the catalyst is regenerated). As described in detail herein, the catalyst can be circulated between these two units. Described herein are systems and methods that allow a portion of the catalyst to bypass the combustor, and are better understood with respect to the embodiments described herein, such as those using the context of FIG. 1 .

[0011] The embodiments disclosed herein are described in detail herein in the context of the reactor system of Figure 1 operating as a fluidized dehydrogenation reactor system for producing light olefins, e.g., propylene. However, it should be understood that the principles disclosed and taught herein may be applicable to other systems utilizing different system components oriented in a different manner. For example, the described concepts may likewise be applied to other systems having alternative reactor units and combustors (sometimes referred to herein as regeneration units), such as those operated under non-flow conditions or including downers rather than risers. Furthermore, it should be understood that not all parts of Figure 1 should be construed as essential to the claimed subject matter.

[0012] Referring now to FIG. 1 , an exemplary reactor system 102 that may be suitable for use in the methods and / or apparatuses described herein is illustrated schematically. The reactor system 102 generally includes multiple system components, such as a reactor section 200 and a catalytic treater section 300. As described herein, a “system component” refers to a portion of the reactor system 102, such as, for example, a reactor, a separator, a transfer line, or a combination thereof. As used herein in the context of FIG. 1 , the reactor section 200 generally refers to the portion of the reactor system 102 where the primary process reaction (e.g., dehydrogenation) occurs to form a product stream. A feed stream enters the reactor section 200, is converted to a product stream (containing product and unreacted feed), and exits the reactor section 200. The reactor section 200 includes a reactor 202, which may include an upstream reactor section 250 and a downstream reactor section 230. 1 , reactor section 200 may further include a catalyst separation section 210 that serves to separate the catalyst from the chemical products formed in reactor 202. Also, as used herein, catalytic treater 300 generally refers to the portion of reactor system 102 where the catalyst is treated in some manner, such as by combustion, to improve catalytic activity by, for example, decoking and / or heating the catalyst. Catalytic treater 300 may include combustor 350 and riser 330, and may further include catalyst separation section 310. In one or more embodiments, catalyst separation section 210 may be in fluid communication with combustor 350 (e.g., via water column 426), and catalyst separation section 310 may be in fluid communication with upstream reactor section 250 (e.g., via water column 424 and transfer riser 430).

[0013] Generally, as described herein, in the embodiment shown in FIG. 1 , a catalyst is circulated between the reactor section 200 and the catalyst treatment section 300. It should be understood that references to “catalysts” herein may refer to solid materials that have catalytic activity for a desired reaction, or may similarly refer to other particulate solids referred to in connection with the system of FIG. 1 that affect the reaction, but are not necessarily catalytically active. The terms “catalytic activity” and “catalyst activity” refer to the extent to which a catalyst is capable of catalyzing a reaction taking place within a reactor system. A catalyst exiting the reactor section 200 may be a deactivated catalyst. As used herein, “deactivated” may refer to a catalyst that is less catalytically active or cooler than the catalyst entering the reactor section 200. However, a deactivated catalyst may retain some catalytic activity. The reduced catalytic activity may result from contamination by materials such as carbon coke. Reactivation (sometimes referred to herein as "regeneration") can remove contaminants such as carbon deposits, increase the temperature of the catalyst, or both. In embodiments, a deactivated catalyst may be reactivated by catalyst reactivation in catalytic treater 300. The deactivated catalyst may be reactivated by, but is not limited to, combustion to remove carbon deposits, restoring catalyst acidity, oxidizing the catalyst, other reactivation processes, or combinations thereof. In some embodiments, the catalyst may be heated during reactivation by combustion of a supplemental fuel, such as hydrogen, methane, ethane, propane, natural gas, or combinations thereof. The reactivated catalyst from catalytic treater 300 is then returned to reactor section 200.

[0014] In a non-limiting example, the reactor system 102 described herein may be utilized to produce light olefins from a hydrocarbon feed stream. According to one or more embodiments, the reaction may be a dehydrogenation reaction. According to such embodiments, the hydrocarbon feed stream may include one or more of ethylbenzene, ethane, propane, n-butane, and i-butane. In one or more embodiments, the hydrocarbon feed stream may include 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% ethylbenzene. In one or more embodiments, the hydrocarbon feed stream may include 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% ethane. In additional embodiments, the hydrocarbon feed stream may comprise 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% propane. In additional embodiments, the hydrocarbon feed stream may comprise 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% n-butane. In additional embodiments, the hydrocarbon feed stream may comprise 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% i-butane. In additional embodiments, the hydrocarbon feed stream may comprise 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 total of ethane, propane, n-butane, and i-butane.

[0015] 1, a feed stream may enter reactor 202 through feed inlet 434, and a product stream may exit reactor system 102 via pipe 420. According to one or more embodiments, reactor system 102 may operate by supplying a chemical feed (e.g., a chemical feed in a feed stream) and a fluidized catalyst to upstream reactor section 250. The chemical feed contacts the catalyst in upstream reactor section 250, and each flows upward into and through downstream reactor section 230 to produce a chemical product.

[0016] Referring now in detail to FIG. 1 , the reactor section 200 may comprise 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 with the downstream reactor section 230. As shown in FIG. 1 , the upstream reactor section 250 may be positioned below the downstream reactor section 230. Such a configuration may be referred to as an upflow configuration for the reactor 202. The upstream reactor section 250 may comprise a vessel, drum, barrel, vat, or other suitable containment vessel for a given chemical reaction. As shown in FIG. 1 , the upstream reactor section 250 may be connected to the downstream reactor section 230 via the transition section 258. The upstream reactor section 250 may generally comprise a larger cross-sectional area than the downstream reactor section 230. The transition section 258 may 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 projects inward from the upstream reactor section 250 toward the downstream reactor section 230. For example, the transition section 258 may be a frustum.

[0017] The upstream reactor section 250 can be connected to a transfer riser 430 that can provide reactivated catalyst in a feed stream to the reactor section 200 during operation. The reactivated catalyst and / or reaction chemicals can be mixed in a distributor 260 housed within the upstream reactor section 250. Catalyst entering the upstream reactor section 250 via the transfer riser 430 can be sent to the transfer riser 430 through a distributor 424 and thus arrives from the catalyst treatment section 300. In some embodiments, the catalyst may enter the transfer riser 430 directly from the catalyst separation section 210 via a distributor 422, in which case the catalyst enters the upstream reactor section 250; in such embodiments, a portion of the catalyst does not pass through the catalyst treatment section 300. Catalyst can also be fed directly to the upstream reactor section 250 via the distributor 422 (not shown in FIG. 1 ). This catalyst may be somewhat deactivated but may still be suitable for reaction in the upstream reactor section 250 in some embodiments, especially when used in conjunction with a reactivated catalyst.

[0018] 1 , in one or more embodiments, based on the shape, size, and other process conditions (such as temperature and pressure) of the upstream reactor section 250 and the downstream reactor section 230, the upstream reactor section 250 can operate as a fluidized bed, such as a fast fluidized bed, turbulent bed, or bubbling bed upflow reactor, while the downstream reactor section 230 can operate more in a plug flow regime, such as a riser reactor. For example, the reactor 202 of FIG. 1 may have the upstream reactor section 250 operating as a fast fluidized bed, turbulent bed, or bubbling bed reactor and the downstream reactor section 230 operating as a dilute-phase riser reactor, such that the average catalyst and gas flows move upward simultaneously. "Average flow," as that term is used herein, refers to net flow, i.e., total upward flow minus countercurrent or reflux, as is generally typical of fluidized particle behavior. As described herein, a "fast fluidized" reactor may refer to a reactor utilizing a fluidization regime in which the superficial velocity of the gas phase is greater than the choking velocity and may be semi-dense during operation. As described herein, a "turbulent" reactor may refer to a fluidization regime in which the superficial velocity is less than the choking velocity and is denser than the fast fluidization regime. As described herein, a "bubbling bed" reactor may refer to a fluidization regime in which well-defined gas bubbles within a dense bed exist in two distinct phases. "Choking velocity" refers to the minimum velocity required to maintain solids in a dilute phase mode in a vertical conveying line. As described herein, a "dilute phase riser" may refer to a riser reactor operating at a conveying velocity, in which the gas and catalyst have approximately the same velocity in the dilute phase.

[0019] According to an embodiment, the chemical products and catalyst may be discharged from downstream reactor section 230 and sent to separation device 220 in catalyst separation section 210, where the catalyst is separated from the chemical products and the chemical products are transported from catalyst separation section 210. According to one or more embodiments, following separation from the vapor in separation device 220, the catalyst may generally travel through stripper 224 to catalyst outlet port 222, where the catalyst is transported out of reactor section 200 via water column 426 to catalyst treatment section 300.

[0020] According to one or more embodiments, separator 220 may be a cyclonic separation system, which may include two or more stages of cyclonic separation. In embodiments in which separator 220 includes two or more stages of cyclonic separation, the first separator into which the fluidized stream enters is referred to as the primary cyclonic separator. The fluidized effluent from the primary cyclonic separator may enter a secondary cyclonic separator for further separation. Primary cyclonic separators may include, for example, primary cyclones 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 cyclones are described, for example, in U.S. Pat. Nos. 4,579,716, 5,190,650, and 5,275,641, each of which is incorporated herein by reference in its entirety. Some separation systems utilizing a primary cyclone as the primary cyclone separator use one or more sets of additional cyclones, e.g., secondary and tertiary cyclones, to further separate the catalyst from the product gas. It should be understood that any primary cyclone separator can be used in embodiments of the presently disclosed technology.

[0021] 1 , at least a portion of the separated catalyst exits reactor section 200 and enters catalyst processing section 300 through catalyst outlet ports 222, 223 via transfer lines 506, 508, respectively. In some embodiments, additional catalyst may be returned to reactor 202 via transfer line 422 as a recycle stream that is not sent to catalyst processing section 300.

[0022] As described in embodiments herein, the catalyst is separated into at least two portions: a first catalyst portion that travels through transfer line 506 and a second catalyst portion that travels through transfer line 508. The sum of the catalyst flows in transfer lines 506 and 508 may be approximately equal to the catalyst flow in transfer line 424, which returns the catalyst from catalyst processing section 300 to reactor section 200. The first catalyst portion travels through transfer line 506 to combustor 350. The second catalyst portion travels through transfer line 508 to a region downstream of combustor 350, as described herein.

[0023] According to an embodiment, the first catalyst portion is transported from the catalyst separation section 210 to the combustor 350. In the combustor 350, the first catalyst portion can be treated, for example, by combustion with oxygen. For example, but not limited to, the catalyst can be decarbonized and / or a supplemental fuel can be burned to heat the catalyst. The catalyst then exits the combustor 350 and passes through the riser 330 to the end-of-riser separator 378, where the gas and solid components from the riser 330 are at least partially separated. The vapor and remaining solids are transported to the secondary separator 320 in the catalyst separation section 310, where the remaining catalyst is separated from gases from the catalytic treatment (e.g., gases emitted by the combustion of spent catalyst or supplemental fuel, referred to herein as flue gas). The flue gas can exit the catalytic treatment section 300 via the outlet pipe 432. The separated catalyst (the catalyst of the first catalyst portion) then passes through the oxygen treatment zone 370 in the catalyst separation section 310.

[0024] According to one or more embodiments, the second catalyst portion bypasses the combustor 350 and is mixed with the second catalyst portion (processed within the combustor 350). For example, as shown in FIG. 1 , the second catalyst portion is transported via transfer line 508 to the catalyst treatment section 300 downstream of the combustor 350 and upstream of the oxygen treatment zone 370. At this point, the first catalyst portion and the second catalyst portion are recombined to form a recombined catalyst stream. After passing through the oxygen treatment zone 370, the combined catalyst stream is sent via the distribution tower 424 and transfer riser 430 to the reactor section 200, where it can be further utilized in catalytic reactions. Thus, the catalyst can circulate between the reactor section 200 and the catalyst treatment section 300 during operation.

[0025] Referring now to catalytic treat section 300, as shown in FIG. 1 , combustor 350 of catalytic treat section 300 may include one or more lower reactor section inlet ports 352 and may be in fluid communication with riser 330. An oxygen-containing gas, such as air, may be delivered to combustor 350 through pipe 428. Combustor 350 may be in fluid communication with the first catalyst section via a water column 506, which may deliver the first catalyst section (e.g., spent catalyst) from reactor section 200 to catalytic treat section 300 for regeneration. Combustor 350 and riser 330, collectively referred to as catalytic combustion reactor 302, may operate under a similar or identical fluidization regime as disclosed for upstream reactor section 250 and downstream reactor section 230 of reactor section 200. That is, the combustor 350 may operate as a fluidized bed, such as in a fast fluidized bed, turbulent bed, or bubbling bed upflow reactor, while the riser 330 may operate more in a plug flow regime, such as a riser reactor. The geometries described with respect to the upstream reactor section 250 and the downstream reactor section 230 are equally applicable to the combustor 350 and the riser 330. Additionally, the combustor 350 may also include a fuel inlet 354 through which a fuel, such as a hydrocarbon stream, may be supplied to the combustor 350.

[0026] As described in one or more embodiments, following separation of the flue gas from the first catalyst portion in the end-of-riser separator 378 and the secondary separation unit 320, the treated first and second catalyst portions (referred to herein as the recombined catalyst stream) are treated with an oxygen-containing gas in the oxygen treatment zone 370. In some embodiments, the oxygen treatment zone 370 comprises a fluid-solid contactor. The fluid-solid contactor may include a baffle or grid structure to facilitate contact of the treated catalyst with the oxygen-containing gas. Examples of fluid-solid contactors are described in more detail in U.S. Pat. Nos. 9,827,543 and 9,815,040. The fluidization regime within the oxygen treatment zone 370 may be bubbling bed fluidization. The oxygen treatment zone 370 may include an oxygen-containing gas inlet 372 through which an oxygen-containing gas may be delivered to the oxygen treatment zone 370 for oxygen treatment of the recombined catalyst.

[0027] In some embodiments, following the oxygen treatment zone 370, the catalyst may be contacted with nitrogen, steam, or another non-reactive gas in a stripping zone, which may strip one or more components from the catalyst.

[0028] As described herein, in one or more embodiments, it may be beneficial to bypass combustor 350 with at least a portion of the catalyst. It has been discovered that the catalyst may be deactivated in combustor 350 with respect to dehydrogenation activity. Without being bound to any particular theory, the catalyst may be deactivated in combustor 350 and then reactivated by exposure to oxygen in oxygen treatment zone 370. Bypassing combustor 350 with a portion of the catalyst may result in better catalyst activation, which may be beneficial to the dehydrogenation reaction yield, etc.

[0029] Furthermore, exposure to auxiliary fuel combustion in combustor 350 can shorten the active life of the catalyst, i.e., permanent deactivation of the catalyst, necessitating replacement with fresh catalyst, is required over extended periods of operation, and exposure to auxiliary fuel combustion is believed to be the primary cause of this deactivation. Therefore, it is believed that the systems described herein, in which a portion of the catalyst bypasses combustor 350, can extend useful catalyst life and reduce costs by using less fresh catalyst.

[0030] In one or more embodiments, the mass ratio of the catalyst flow (to the combustor 350) of the first catalyst portion to the second catalyst portion (bypassing the combustor 350) can be between 3:7 and 9:1, e.g., between 3:7 and 4:6, between 3:7 and 5:5, between 3:7 and 6:4, between 3:7 and 7:3, between 7:3 and 8:2, between 4:7 and 9:1, between 5:5 and 9:1, between 6:4 and 9:1, between 7:3 and 9:1, or between 8:2 and 9:1. In additional embodiments, the mass ratio of the catalyst flow (to the combustor 350) of the first catalyst portion to the second catalyst portion (bypassing the combustor) can be between 3:7 and 7:3, e.g., between 3:7 and 4:6, between 4:6 and 5:5, between 5:5 and 6:4, between 6:4 and 7:3, or any combination of these ranges. As described in detail herein, this ratio can vary based on several factors, such as the thermal needs of the dehydrogenation unit, where the first catalytic section is heated by combustion of the supplemental fuel and the second section is substantially unheated in catalytic processing section 300. A relatively high mass ratio (e.g., a ratio of at least 3:7 or greater) of the catalyst flow in the first catalytic section (to combustor 350) to the catalyst flow in the second catalytic section (bypassing combustor 350) is believed to be beneficial because, in these embodiments, the catalyst can be adequately heated by combustion in combustor 350 to continuously heat reactor 202 as required for the endothermic dehydrogenation reaction. That is, a relatively high mass ratio of catalyst flow in the first catalyst portion (to combustor 350) to catalyst flow in the second catalyst portion (bypassing combustor 350) (e.g., a ratio of at least 3:7 or more) may be beneficial because the endothermic dehydrogenation reaction requires heat, which may be primarily provided by the catalyst or other solids entering reactor 202, allowing the temperature in the combustor to operate at a moderate temperature compared to embodiments in which a greater amount of catalyst bypasses combustor 350. On the other hand, a relatively low mass ratio of catalyst flow in the first catalyst portion (to combustor 350) to the second catalyst portion (bypassing combustor 350) (e.g., a ratio of 9:1 or less, or 7:3 or less, or even less) may be beneficial because the second catalyst portion bypassing combustor 350 is not exposed to auxiliary fuel combustion in combustor 350, which can cause short- and long-term catalyst deactivation.That is, in these embodiments, the catalyst that bypasses the combustor may be heated by the catalyst passing through the combustor 350 while not being exposed to auxiliary fuel combustion that may cause catalyst deactivation.

[0031] According to additional embodiments, a portion of the catalyst is recycled to the combustor 350. For example, as shown in FIG. 1 , a catalyst transfer line 502 can return catalyst from the catalyst treatment section 300 (upstream of the oxygen treatment zone 370) to the combustor 350. Such a recycled flow via transfer line 502 can be useful for controlling the density of the catalyst within the combustor 350. For example, if a relatively large amount of catalyst is present in the second catalyst section (via line 508), the catalyst density within the combustor 350 may be correspondingly low; therefore, additional catalyst recirculation via line 502 can enable better control of the catalyst density to maintain proper fluidization within the combustor 350.

[0032] According to some embodiments, a portion of the recombined catalyst stream is recycled to combustor 350 before entering oxygen treatment zone 370. In such embodiments, transfer line 502 may be downstream of the inlet of transfer line 508 that delivers catalyst directly from reactor section 200, such that combination of the first catalyst portion and the second catalyst portion occurs upstream of the inlet to transfer line 520. According to additional embodiments, a portion of the first catalyst portion is recycled to combustor 350 before entering oxygen treatment zone 370. In such embodiments, transfer line 502 may be upstream of the inlet of transfer line 508 that delivers catalyst directly from reactor section 200, such that only the first catalyst portion is sent to transfer line 508.

[0033] In one or more embodiments, light olefins may be present in a "product stream," sometimes referred to as an "olefin-containing effluent," and may include light olefins. Such a stream may exit the reactor system of FIG. 1 and be subsequently processed. As used in this disclosure, the term "light olefin" refers to one or more of ethylene, propylene, and butene. In further embodiments, the feed may include ethylbenzene, which is converted to styrene, present in the product stream, an embodiment of the olefin-containing materials described herein. The term butene includes any isomer of butene, such as α-butylene, cis-β-butylene, trans-β-butylene, and isobutylene. In some embodiments, the olefin-containing effluent comprises at least 30 wt. % light olefins, based on the total weight of the olefin-containing effluent. For example, the olefin-containing effluent may contain at least 35 wt.% light olefins, at least 45 wt.% light olefins, at least 55 wt.% light olefins, at least 65 wt.% light olefins, or at least 75 wt.% light olefins, based on the total weight of the olefin-containing effluent. The olefin-containing effluent may further contain unreacted components of the feed stream and other reaction products that are not considered light olefins. The light olefins can be separated from the unreacted components in a subsequent separation step.

[0034] In a non-limiting example, the reactor system 102 described herein may be utilized to produce light olefins from a hydrocarbon feed stream. Light olefins may be produced from a wide variety of hydrocarbon feed streams by utilizing different reaction mechanisms. As described herein, light olefins may be produced by utilizing a dehydrogenation reaction.

[0035] According to one or more embodiments, the reaction may be a dehydrogenation reaction. According to such embodiments, the hydrocarbon feed stream may comprise one or more of ethylbenzene, ethane, propane, n-butane, and i-butane. In one or more embodiments, the hydrocarbon feed stream may comprise 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% ethylbenzene. In one or more embodiments, the hydrocarbon feed stream may comprise 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% ethane. In additional embodiments, the hydrocarbon feed stream may comprise 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% propane. In additional embodiments, the hydrocarbon feed stream may comprise 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% n-butane. In additional embodiments, the hydrocarbon feed stream may comprise 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% i-butane. In additional embodiments, the hydrocarbon feed stream may comprise 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 total of ethane, propane, n-butane, and i-butane.

[0036] In one or more embodiments, the dehydrogenation reaction may utilize a gallium and / or platinum particulate solid as a catalyst. In such embodiments, the particulate solid may include a gallium and / or platinum catalyst. As described herein, a gallium and / or platinum catalyst includes gallium, platinum, or both. The gallium and / or platinum catalyst may be supported on an alumina or alumina-silica support and may optionally include potassium. Such gallium and / or platinum catalysts are disclosed in U.S. Pat. No. 8,669,406, which is incorporated herein by reference in its entirety. However, it should be understood that other suitable catalysts may be utilized to carry out the dehydrogenation reaction.

[0037] In one or more embodiments, the reaction mechanism may be dehydrogenation followed by combustion (in the same chamber). In such embodiments, the dehydrogenation reaction may produce hydrogen as a by-product, and the oxygen carrier material may contact the hydrogen to promote combustion of the hydrogen to form water. An example of such a reaction mechanism, which is contemplated as a possible reaction mechanism for the systems and methods described herein, is disclosed in WO 2020 / 046978, the teachings of which are incorporated herein by reference in their entirety. [Example]

[0038] This example illustrates the variation in dehydrogenation catalytic activity of a catalyst exposed to the combustion of an auxiliary fuel. Identifying the consequences of exposure to the combustion of an auxiliary fuel, as described herein, can provide a rationale for the usefulness of the systems described herein in which a portion of the catalyst bypasses the combustor.

[0039] Propane dehydrogenation tests were conducted in a laboratory-scale fixed-bed reactor at ambient pressure using simulated reaction-combustion-regeneration (standard) and reaction-regeneration (bypass) cycles. For each test, 0.5 g of catalyst sample was mixed with 1.0 g of inert silicon carbide and packed into a quartz reactor tube. The standard cycle included a reaction step, a combustion step, and a regeneration step. First, the propane dehydrogenation reaction step was performed at a total flow rate of 51.38 standard cubic centimeters per minute (sccm) and a reaction time of 10 hours. -1 The reactor was then purged under flowing helium and heated to 730°C. A fuel combustion step was then performed at a total flow rate of 50 sccm and for 0.1 hours. -1 The cycle was carried out at a reactor temperature of 730°C for 180 seconds under a feed composition of 2.5 mol% methane in equilibrium air at a WHSV of 100% methane. A regeneration step was then carried out at a reactor temperature of 730°C for 120 seconds under a feed composition of 100% air at a flow rate of 40 sccm. The reactor tube was then purged under flowing helium and cooled to 625°C to begin the next cycle. In the bypass cycle, the process was carried out identically to the standard cycle, except that the fuel combustion step was omitted. That is, the regeneration step was carried out after the reaction step and purging under helium. For each propane dehydrogenation reaction step, the reactor effluent was analyzed using gas chromatography (GC) with an on-stream time of 30 seconds, and the propane conversion was calculated from the product gas concentration on a carbon atom basis. The catalyst used in the test contained platinum and gallium on an alumina support.

[0040] Tests were run through a full standard cycle (including exposure to methane combustion), and the subsequent propane conversion data for each cycle is shown in Figure 2. As can be seen, propane conversion steadily decreases over the course of the cycle.

[0041] Another test was performed on all standard cycles except for the bypass cycles at cycles 20, 40, and 60. The data from this experiment is provided in Figure 3 and shows a clear increase in propane conversion after the bypass cycle (indicative of greater dehydrogenation catalytic activity). Therefore, it can be inferred that the catalyst that bypasses the combustor in embodiments of the present disclosure generally has higher activity, even when both are exposed to a regenerative oxygen treatment.

[0042] The present disclosure includes numerous embodiments. In one embodiment, a method of forming a dehydrogenation product includes dehydrogenating a feed stream in a reactor in the presence of a catalyst to form a dehydrogenation product, separating at least a portion of the product stream from the catalyst, separating the catalyst into at least a first catalyst portion and a second catalyst portion, passing the first catalyst portion to a combustor, where the first catalyst portion is heated in the combustor by combustion of a supplemental fuel, passing the first catalyst portion out of the combustor, combining the first catalyst portion with a second catalyst portion downstream of the combustor to form a recombined catalyst stream such that the second catalyst portion bypasses the combustor, passing the recombined catalyst stream through an oxygen treatment zone, and passing the recombined catalyst stream through a reactor.

[0043] Another embodiment is any single or combination of the above embodiments, wherein the mass ratio of the catalyst stream of the first catalyst portion to the second catalyst portion is from 3:7 to 9:1.

[0044] Another embodiment is any single or combination of the above embodiments, wherein the mass ratio of the catalyst stream of the first catalyst portion to the second catalyst portion is from 3:7 to 7:3.

[0045] Another embodiment is any single or combination of the above embodiments, wherein the dehydrogenation reaction forms carbon deposits on the catalyst.

[0046] Another aspect is any single or combination of the above aspects, wherein at least a portion of the carbon deposits are combusted in a combustor.

[0047] Another aspect is any single or combination of the above aspects, wherein the supplemental fuel comprises hydrogen, methane, ethane, propane, or natural gas.

[0048] Another embodiment is any single or combination of the above embodiments, wherein the product stream comprises one or more of ethylene, propylene, butene, or styrene.

[0049] Another embodiment is any single or combination of the above embodiments, wherein the product stream comprises at least 30 wt.% ethane, propane, butane, or ethylbenzene.

[0050] Another embodiment is any single or combination of the above embodiments, wherein the fluidization regime in the oxygen treatment zone is bubbling bed fluidization.

[0051] Another embodiment is any single or combination of the above embodiments, wherein the first catalyst portion is deactivated for dehydrogenation activity in the combustor and then reactivated for dehydrogenation activity in the oxygen treatment zone.

[0052] Another embodiment is any single or combination of the above embodiments, wherein the recombined catalyst stream passes through a strip zone downstream of the oxygen treatment zone.

[0053] Another embodiment is any single embodiment or combination of the above embodiments, wherein the catalyst comprises gallium and platinum.

[0054] Another embodiment is any single embodiment or combination of the above embodiments, wherein the catalyst further comprises an alumina support.

[0055] Another embodiment is any single or combination of the above embodiments, wherein the dehydrogenation reaction is followed by combustion of the hydrogen product of the dehydrogenation reaction, and an oxygen carrier material is present in the reactor.

[0056] Another embodiment is any single or combination of the above embodiments, wherein a portion of the recombined catalyst stream or a portion of the first catalyst portion is recycled to the combustor before entering the oxygen treatment zone.

[0057] In one or more embodiments, a flow or the like is described as being "passed" from one system component to another. It should be understood that passing can describe a direct pass (where the flow passes directly between two designated system components) or an indirect pass (where the flow passes between two system components via one or more intermediate system components or lines).

[0058] It will be apparent to those skilled in the art that various modifications and variations can be made to the technology of the present disclosure without departing from the spirit and scope of the technology. Since combinations, subcombinations, and variations of the disclosed embodiments incorporating the spirit and substance of the technology of the present disclosure may occur to those skilled in the art, the technology should be construed as including all within the scope of the appended claims and their equivalents. Furthermore, although some aspects of the present disclosure may be identified herein as preferred or particularly advantageous, it is intended that the present disclosure is not limited to these aspects.

[0059] It should be noted that the various details described in this disclosure should not be construed as implying that these details relate to elements that are essential components of the various embodiments described in this disclosure, even if a particular element is illustrated in each of the drawings accompanying this specification. Unless specifically identified as such, features disclosed and described herein should not be construed as "essential." Contemplated embodiments of the technology include those that include some or all of the features of the appended claims.

[0060] Where relevant, when a composition is described as "comprising" one or more elements, embodiments of the composition "consisting of" or "consisting essentially of" those one or more elements are contemplated herein.

[0061] It is understood that the compositional ranges of chemical components in a stream or reactor should, in some embodiments, be understood to contain a mixture of isomers of that component. For example, a compositional range specifying butene may include a mixture of various isomers of butene. It is understood that the examples provide compositional ranges for various streams, and that the total amount of isomers of a particular chemical composition may comprise a range.

[0062] It should be noted that one or more of the following claims utilize the term "where" or "wherein" as a transitional phrase. It should be noted that, for purposes of defining the art, this term is introduced in the claims as an open-ended transitional phrase used to introduce the recitation of a series of features of a structure, and should be interpreted in a similar manner to the more commonly used open-ended preamble term "comprising."

[0063] It should be understood that any two quantitative values ​​assigned to a property may constitute a range for that property, and all combinations of ranges formed from all stated quantitative values ​​for a given property are contemplated in the application. When multiple ranges are given for quantitative values, these ranges may be combined to form larger ranges, which are contemplated in the embodiments described herein.

[0064] As understood in the context of the term as used herein, the term "passing" can include passing a substance directly between two portions of the disclosed system, and in some other instances, can mean passing a substance indirectly between two portions of the disclosed system. For example, indirect passing can include passing the specified substance through an intermediate separation device, valve, sensor, etc.

Claims

1. 1. A process for forming a dehydrogenation product, the process comprising: dehydrogenating the feedstream in a reactor in the presence of a catalyst to form a dehydrogenation product; separating at least a portion of the product stream from the catalyst; separating the catalyst into at least a first catalyst portion and a second catalyst portion; delivering the first catalyst portion to a combustor, wherein the first catalyst portion is heated within the combustor by combustion of a supplemental fuel; passing the first catalyst portion out of the combustor and combining the first catalyst portion with the second catalyst portion downstream of the combustor to form a recombined catalyst stream such that the second catalyst portion bypasses the combustor; passing the recombined catalyst stream through an oxygen treatment zone; and passing the recombined catalyst stream through the reactor.

2. 10. The method of claim 1, wherein the mass ratio of the catalyst flow of the first catalyst portion to the second catalyst portion is from 3:7 to 9:

1.

3. 10. The method of claim 1, wherein the mass ratio of catalyst flow of the first catalyst portion to the second catalyst portion is from 3:7 to 7:

3.

4. 4. The method of claim 1, wherein the dehydrogenation reaction forms carbon deposits on the catalyst.

5. The method of claim 4 , wherein at least a portion of the carbon deposits are combusted in the combustor.

6. The method of any one of claims 1 to 5, wherein the supplemental fuel comprises hydrogen, methane, ethane, propane, or natural gas.

7. The method of any one of claims 1 to 6, wherein the product stream comprises one or more of ethylene, propylene, butene, or styrene.

8. 8. The method of any one of claims 1 to 7, wherein the product stream comprises at least 30 wt% ethane, propane, butane, or ethylbenzene.

9. A process according to any one of claims 1 to 8, wherein the fluidisation regime in the oxygen treatment zone is a bubbling bed fluidisation.

10. 10. The method of any one of claims 1 to 9, wherein the first catalyst portion is deactivated for dehydrogenation activity in the combustor and then reactivated for dehydrogenation activity in the oxygen treatment zone.

11. The method of any one of claims 1 to 10, wherein the recombined catalyst stream passes through a strip zone downstream of the oxygen treatment zone.

12. The method of any one of claims 1 to 11, wherein the catalyst comprises gallium and platinum.

13. The method of claim 12 wherein the catalyst further comprises an alumina support.

14. 14. A method according to any one of claims 1 to 13, wherein the dehydrogenation reaction is followed by combustion of the hydrogen product of the dehydrogenation reaction, and an oxygen carrier material is present in the reactor.

15. The method of any one of claims 1 to 14, wherein a portion of the recombined catalyst stream or a portion of the first catalyst portion is recycled to the combustor before entering the oxygen treatment zone.

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