Process for forming dehydrogenation products with combustion bypass of partial catalyst

Abstract

A dehydrogenation product may be formed by a process comprising reacting a feed stream in a reactor by a dehydrogenation reaction 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, and passing the first catalyst portion to a combustor. The first catalyst portion may be heated in the combustor by combusting a supplemental fuel. The method may also include 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. The method may also include passing the recombined catalyst stream through an oxygen treatment zone, and passing the recombined catalyst stream to the reactor.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 428,520, filed on November 29, 2022, the entire disclosure of which is hereby incorporated by reference. Technical field

[0003] The various embodiments described herein generally relate to chemical processing, and more specifically, to methods and systems for producing light olefins. Background art

[0004] Light olefins such as propylene can be used as base materials 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 worldwide demand for light olefins. Suitable processes for producing light olefins generally depend on the given chemical feed and include those processes that utilize fluidized catalysts. For example, light olefins can be formed by the catalytic dehydrogenation of alkanes. However, there is a need to improve the systems for preparing dehydrogenation products. Summary of the invention

[0005] Olefin products can be produced by catalytic dehydrogenation, where the catalyst is circulated between a reactor (where the dehydrogenation reaction occurs) and a burner (where the catalyst is heated by burning a supplementary fuel), and then exposed to oxygen in an oxygen treatment zone. According to the embodiments described herein, a portion of the catalyst can bypass the burner and recombine downstream of the burner and upstream of the oxygen treatment zone with that portion of the catalyst that is delivered to the burner. Such a process can be beneficial by improving the catalyst lifetime and reducing catalyst deactivation that can occur when exposed to the combustion of the supplementary fuel in the burner.

[0006] According to one or more embodiments of the present disclosure, a dehydrogenation product can be formed by a method that includes reacting a feed stream in a reactor in the presence of a catalyst by a dehydrogenation reaction 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 delivering the first catalyst portion to a burner. The first catalyst portion can be heated in the burner by burning a supplementary fuel. The method can also include delivering the first catalyst portion out of the burner, and combining the first catalyst portion downstream of the burner with the second catalyst portion to form a recombined catalyst stream such that the second catalyst portion bypasses the burner. The method can also include delivering the recombined catalyst stream through an oxygen treatment zone, and delivering the recombined catalyst stream to the reactor.

[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 of ordinary skill in the art from the description including the drawings and the claims, or may be recognized by practicing the described embodiments. Drawings are included to provide a further understanding of the embodiments and, together with the detailed description, are used to explain the principles and operations 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. Description of the Drawings

[0008] The following detailed description can be better understood when read in conjunction with the following drawings, in which:

[0009] Figure 1 Schematically depicts a reactor system according to one or more embodiments of the present disclosure;

[0010] Figure 2 Shows experimental data as described herein; and

[0011] Figure 3 Shows additional experimental data as described herein.

[0012] When describing Figure 1 a simplified schematic illustration, many valves, temperature sensors, electronic controllers, etc. that can be used and are well known to those of ordinary skill in the art are not included. In addition, the accompanying components that are typically included in such reactor systems, such as air supplies, heat exchangers, buffer tanks, etc., are not included. However, it should be understood that these components are within the scope of the present disclosure.

[0013] Reference will now be made in more detail to various embodiments, some of which are illustrated in the drawings. Detailed Description

[0014] As described herein, the present disclosure relates to methods and systems for preparing chemical products (such as light olefins) by dehydrogenation. Embodiments of the present invention may utilize a reactor system including a reactor in which a dehydrogenation reaction takes place and a burner in which a catalyst is regenerated. As described in detail herein, the catalyst can be cycled between these two units. Systems and methods are described that allow a portion of the catalyst to bypass the burner and are better understood in the context of the embodiments described herein, such as those using Figure 1 in the context of the embodiments.

[0015] As described herein, operating as a fluidized dehydrogenation reactor system to produce light olefins (such as propylene) Figure 1The embodiments disclosed herein are described in detail in the context of a reactor system. However, it should be understood that the principles disclosed and taught herein can be applied to other systems that utilize different system components oriented in different ways. For example, the concepts described can be equivalently applied to other systems having alternative reactor units and burners (sometimes referred to herein as regeneration units), such as those operating under non-fluidized conditions, or those including downcomers instead of risers. It should also be understood that not all parts of Figure 1 should be construed as being necessary for the claimed subject matter.

[0016] Now referring to Figure 1 , an exemplary reactor system 102 that can be applicable to the methods and / or apparatuses described herein is schematically depicted. Reactor system 102 generally includes a plurality of system components, such as a reactor section 200 and a catalyst handling section 300. As used herein, a "system component" refers to a part of reactor system 102, such as a reactor, a separator, a transfer line, combinations thereof, etc. As used herein in the context of Figure 1 , reactor section 200 generally refers to the part of reactor system 102 where the main process reactions (e.g., dehydrogenation) occur to form a product stream. A feed stream enters reactor section 200, is converted into a product stream (containing products and unreacted feed), and exits reactor section 200. Reactor section 200 includes a reactor 202, which can include an upstream reactor section 250 and a downstream reactor section 230. According to one or more embodiments, as depicted in Figure 1 , reactor section 200 can additionally include a catalyst separation section 210 for separating the catalyst from the chemical products formed in reactor 202. Further, as used herein, catalyst handling section 300 generally refers to the part of reactor system 102 where the catalyst is treated in some manner, such as by combustion, to improve catalytic activity, for example, by decoking and / or heating the catalyst. Catalyst handling section 300 can include a burner 350 and a riser 330, and can additionally include a catalyst separation section 310. In one or more embodiments, catalyst separation section 210 can be in fluid communication with burner 350 (e.g., via a standpipe 426), and catalyst separation section 310 can be in fluid communication with upstream reactor section 250 (e.g., via standpipes 424 and transfer riser 430).

[0017] Generally as described herein, in the embodiment shown in Figure 1 , the catalyst cycles between reactor section 200 and catalyst handling section 300. It should be understood that when "catalyst" is referred to herein, they can refer to solid materials that are catalytically active for the desired reaction, or can equally refer to reference Figure 1Other particulate solids mentioned by the system that may not necessarily have catalytic activity but affect the reaction. The terms "catalytic activity" and "catalyst activity" refer to the degree to which a catalyst can catalyze the reaction taking place in the reactor system. The catalyst leaving the reactor section 200 can be a deactivated catalyst. As used herein, "deactivated" can mean a catalyst with reduced catalytic activity or a cooler catalyst compared to the catalyst entering the reactor section 200. However, the deactivated catalyst may retain some catalytic activity. The reduced catalytic activity can be caused by contamination with substances such as coke. Reactivation (sometimes referred to herein as "regeneration") can remove contaminants such as coke, raise the temperature of the catalyst, or both. In an embodiment, the deactivated catalyst can be reactivated by catalyst reactivation in the catalyst treatment section 300. The deactivated catalyst can be reactivated by, but not limited to, removing coke by combustion, restoring catalyst acidity, oxidizing the catalyst, other reactivation processes, or combinations thereof. In some embodiments, the catalyst can be heated during reactivation by burning supplementary fuels such as hydrogen, methane, ethane, propane, natural gas, or combinations thereof. The reactivated catalyst from the catalyst treatment section 300 is then passed back to the reactor section 200.

[0018] In a non-limiting example, the reactor system 102 described herein can be used to produce light olefins from a hydrocarbon feed stream. According to one or more embodiments, the reaction can be a dehydrogenation reaction. According to such embodiments, the hydrocarbon feed stream can comprise one or more of ethylbenzene, ethane, propane, n-butane, and isobutane. In one or more embodiments, the hydrocarbon feed stream can 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 ethylbenzene. In one or more embodiments, the hydrocarbon feed stream can 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 ethane. In additional embodiments, the hydrocarbon feed stream can 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 propane. In additional embodiments, the hydrocarbon feed stream can 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 n-butane. In additional embodiments, the hydrocarbon feed stream can 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 isobutane. In additional embodiments, the hydrocarbon feed stream can 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 sum of ethane, propane, n-butane, and isobutane.

[0019] As described with respect to Figure 1 the feed stream can enter the feed inlet 434, enter the reactor 202, and the product stream can exit the reactor system 102 via the tube 420. According to one or more embodiments, the reactor system 102 can be operated by feeding a chemical feed (e.g., in the feed stream) and a fluidized catalyst into the upstream reactor section 250. The chemical feed contacts the catalyst in the upstream reactor section 250, and each chemical feed flows upwardly into and through the downstream reactor section 230 to produce a chemical product.

[0020] Referring now in detail to Figure 1 the reactor section 200 can comprise an upstream reactor section 250, a transition section 258, and a downstream reactor section 230, such as a riser. The transition section 258 can connect the upstream reactor section 250 to the downstream reactor section 230. As Figure 1As depicted, the upstream reactor section 250 can be positioned below the downstream reactor section 230. Such a configuration can be referred to as an upflow configuration in the reactor 202. The upstream reactor section 250 can include a vessel, a drum, a barrel, a tank, or other container suitable for a given chemical reaction. As Figure 1 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 generally have a larger cross-sectional area than the downstream reactor section 230. The transition section 258 can taper from the size of the cross-section of the upstream reactor section 250 to the size of the cross-section of the downstream reactor section 230 such that the transition section 258 projects inward from the upstream reactor section 250 into the downstream reactor section 230. For example, the transition section 258 can be a frustum.

[0021] The upstream reactor section 250 can be connected to a transport riser 430 that can provide reactivated catalyst in a feed stream to the reactor section 200 during operation. The reactivated catalyst and / or reactant chemicals can be mixed with a distributor 260 housed in the upstream reactor section 250. The catalyst entering the upstream reactor section 250 via the transport riser 430 can be passed through a standpipe 424 to the transport riser 430 and thus arrives from the catalyst processing section 300. In some embodiments, the catalyst can enter the transport riser 430 directly from the catalyst separation section 210 via a standpipe 422, where the catalyst enters the upstream reactor section 250, and in such embodiments, some of the catalyst does not pass through the catalyst processing section 300. The catalyst can also be fed directly into the upstream reactor section 250 via the standpipe 422 (not Figure 1 depicted). This catalyst can be slightly deactivated but can still be suitable for reaction in the upstream reactor section 250 in some embodiments, particularly when used in combination with reactivated catalyst.

[0022] Still referring to 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 can operate as a fluidized bed, such as in a fast fluidized, turbulent, or bubbling bed upflow reactor, while the downstream reactor section 230 can operate in a more plug flow manner, such as in a riser reactor. By way of example, Figure 1The reactor 202 can 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, such that the average catalyst and gas flows move upward simultaneously. As used herein, the term "average flow" refers to the net flow, i.e., the total upward flow minus the reverse or counter flow, which is typically characteristic of fluidized particles. As described herein, a "fast fluidized" reactor can refer to a reactor utilizing a fluidization scheme in which the superficial velocity of the gas phase is greater than the choking velocity and can be semi-dense in operation. As described herein, a "turbulent" reactor can refer to a fluidization scheme in which the superficial velocity is less than the choking velocity and is denser than the fast fluidization scheme. As described herein, a "bubbling bed" reactor can refer to a fluidization regime in which distinct bubbles are present in a highly dense bed in two distinct phases. The "choking velocity" is the minimum velocity required to maintain solids in a dilute-phase mode in a vertical transport line. As described herein, a "dilute-phase riser" can refer to a riser reactor operating at a transport velocity, where the gas and catalyst have approximately the same velocity in the dilute phase.

[0023] According to an embodiment, the chemical product and catalyst can be transferred from the downstream reactor section 230 to a separation device 220 in the catalyst separation section 210, where the catalyst is separated from the chemical product, and the chemical product is conveyed out of the catalyst separation section 210. According to one or more embodiments, after separating the catalyst from the vapor in the separation device 220, the catalyst can typically move through a stripper 224 to a catalyst outlet port 222, where the catalyst is transferred out of the reactor section 200 via a standpipe 426 and into a catalyst processing section 300.

[0024] 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 separation device. The fluidized effluent from the primary cyclone separation device may enter a secondary cyclone separation device for further separation. The primary cyclone separation device may include, for example, a primary cyclone separator and systems commercially available under the names VSS (commercially available from UOP), LD2 (commercially available from Stone and Webster), and RS2 (commercially available from Stone and Webster). The primary cyclone separator is described, for example, in U.S. Patent Nos. 4,579,716, 5,190,650, and 5,275,641, each of which is incorporated herein by reference in its entirety. In some separation systems that utilize a primary cyclone separator as the primary cyclone separation device, one or more additional sets of cyclone separators, e.g., 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 device may be used in embodiments of the technology disclosed herein.

[0025] Still referring to Figure 1 , at least a portion of the separated catalyst is transferred out of the reactor section 200 and into the catalyst processing section 300 via the catalyst outlet ports 222, 223 through the transfer lines 506, 508, respectively. In some embodiments, additional catalyst may be transferred back to the reactor 202 via the transfer line 422 as a recycle stream that is not sent to the catalyst processing section 300.

[0026] As described in the embodiments herein, the catalyst is separated into at least two portions - a first catalyst portion that moves through the transfer line 506 and a second catalyst portion that moves through the transfer line 508. The sum of the catalyst flows in the transfer line 506 and the transfer line 508 may be approximately equal to the catalyst flow in the transfer line 424 that returns the catalyst from the catalyst processing section 300 to the reactor section 200. The first catalyst portion moves to the burner 350 through the transfer line 506. As described herein, the second portion of the catalyst moves to a region downstream of the burner 350 through the transfer line 508.

[0027] According to an embodiment, a first catalyst portion is conveyed 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. By way of example and not limitation, the catalyst can be decoked and / or combustible make-up fuel can be burned to heat the catalyst. The catalyst is then passed out of the combustor 350 and through the riser 330 to the riser termination separator 378, where the gas and solid components from the riser 330 are at least partially separated. The vapor and remaining solids are conveyed to the secondary separation device 320 in the catalyst separation section 310, where the remaining catalyst is separated from the gas from the catalyst treatment (e.g., the gas emitted by burning the spent catalyst or make-up fuel, referred to herein as flue gas). The flue gas can be passed out of the catalyst treatment section 300 via the outlet pipe 432. The separated catalyst (the catalyst of the first catalyst portion) is then passed through the oxygen treatment zone 370 within the catalyst separation section 310.

[0028] According to one or more embodiments, a second catalyst portion bypasses the combustor 350 and is mixed with the second catalyst portion (which is treated in the combustor 350). For example, as Figure 1 depicted, the second catalyst portion is conveyed via the transfer line 508 to the catalyst treatment section 300 downstream of the combustor 350 and upstream of the oxygen treatment zone 370. At this time, the first catalyst portion and the second catalyst portion are recombined, thereby forming a recombined catalyst stream. After passing through the oxygen treatment zone 370, the combined catalyst stream can be conveyed via the standpipe 424 and the transfer riser 430 to the reactor section 200, where the combined catalyst stream is further used for catalytic reactions. Thus, the catalyst can be circulated between the reactor section 200 and the catalyst treatment section 300 during operation.

[0029] Now referring to the catalyst treatment section 300, as Figure 1As depicted, the burner 350 of the catalyst treatment section 300 can include one or more lower reactor section inlet ports 352 and can be in fluid communication with the riser 330. An oxygen-containing gas (such as air) can be delivered to the burner 350 through the tube 428. The burner 350 can be in fluid communication with a first catalyst section via the standpipe 506, which can supply the first catalyst section (e.g., 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) can be operated in a fluidization scheme similar or identical to that disclosed for the upstream reactor section 250 and the downstream reactor section 230 of the reactor section 200. That is, the burner 350 can operate as a fluidized bed, such as in a fast fluidization, turbulent, or bubbling bed upflow reactor, while the riser 330 can operate in a more plug flow manner, such as in a riser reactor. The geometries described for the upstream reactor section 250 and the downstream reactor section 230 can equally apply to the burner 350 and the riser 330. Additionally, the burner 350 can further include a fuel inlet 354, which can supply a fuel such as a hydrocarbon feed stream to the burner 350.

[0030] As described in one or more embodiments, after separating the flue gas from the first catalyst section in the riser termination separator 378 and the secondary separation device 320, the processed first catalyst section and the second catalyst section (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 includes a fluid-solid contacting device. The fluid-solid contacting device can include baffle or grid structures to facilitate the contact of the processed catalyst with the oxygen-containing gas. Examples of the fluid-solid contacting device are described in further detail in U.S. Patent Nos. 9,827,543 and 9,815,040. The fluidization scheme within the oxygen treatment zone 370 can be of the bubbling bed type. The oxygen treatment zone 370 can include an oxygen-containing gas inlet 372, which can supply the oxygen-containing gas to the oxygen treatment zone 370 for the oxygen treatment of the recombined catalyst.

[0031] In some embodiments, after the oxygen treatment zone 370, the catalyst can be contacted with nitrogen, steam, or another non-reactive gas in a stripping zone, which can strip one or more components from the catalyst.

[0032] As described herein, in one or more embodiments, it may be beneficial to bypass at least a portion of the catalyst around the burner 350. It has been found that the catalyst may be deactivated in the burner 350 with respect to dehydrogenation activity. Without being bound by any particular theory, the catalyst may be deactivated in the burner 350 and then reactivated in the oxygen treatment zone 370 by exposure to oxygen. Bypassing a portion of the catalyst around the burner 350 can result in better catalyst activation, which may be beneficial for dehydrogenation reaction yields and the like.

[0033] In addition, exposure to the combustion of supplemental fuel in the burner 350 can reduce the active life of the catalyst. That is, during long-term operation, permanent deactivation of the catalyst that requires replacement with new catalyst may be necessary, and exposure to the combustion of supplemental fuel appears to be a major driver of such deactivation. Accordingly, it is believed that the system described in the present invention in which a portion of the catalyst bypasses the burner 350 can extend the useful life of the catalyst, thereby reducing costs by using less new catalyst.

[0034] In one or more embodiments, the mass ratio of the first catalyst portion (to burner 350) to the catalyst stream of the second catalyst portion (bypassing burner 350) can be from 3:7 to 9:1, such as 3:7 to 4:6, 3:7 to 5:5, 3:7 to 6:4, 3:7 to 7:3, 7:3 to 8:2, 4:7 to 9:1, 5:5 to 9:1, 6:4 to 9:1, 7:3 to 9:1, or 8:2 to 9:1. In additional embodiments, the mass ratio of the first catalyst portion (to burner 350) to the catalyst stream of the second catalyst portion (bypassing the burner) can be from 3:7 to 7:3, such as 3:7 to 4:6, 4:6 to 5:5, 5:5 to 6:4, 6:4 to 7:3, or any combination of these ranges. As described in detail herein, the ratio can vary based on several factors such as the heat demand in the dehydrogenation unit, where the first catalyst portion is heated by combusting a supplemental fuel, while the second portion may be substantially unheated in catalyst processing section 300. A relatively high mass ratio of the first catalyst portion (to burner 350) to the catalyst stream of the second catalyst portion (bypassing burner 350) is expected to be beneficial (e.g., a ratio of at least 3:7 or even greater), because in these embodiments, the catalyst can be sufficiently heated by combustion in burner 350 to continuously heat reactor 202 according to the needs of the endothermic dehydrogenation reaction. That is, a relatively high mass ratio of the first catalyst portion (to burner 350) to the catalyst stream of the second catalyst portion (bypassing burner 350) is expected to be beneficial (e.g., a ratio of at least 3:7 or even greater), because compared to embodiments where a greater amount of catalyst bypasses burner 350, the temperature in the burner can be operated at a moderate temperature, which, due to the heat required for the endothermic dehydrogenation reaction, can be supplied primarily by the catalyst or other solids entering reactor 202. On the other hand, a relatively low mass ratio of the first catalyst portion (to burner 350) to the catalyst stream of the second catalyst portion (bypassing burner 350) is expected to be beneficial (e.g., less than or equal to 9:1 or less than or equal to 7:3 or even less), because the second catalyst portion bypassing burner 350 is not exposed to the combustion of the supplemental fuel in burner 350, which can lead to short-term and long-term deactivation of the catalyst. That is, in these embodiments, the catalyst bypassing the burner can be heated by the catalyst passing through burner 350 while not being exposed to the combustion of the supplemental fuel that can cause catalyst deactivation.

[0035] According to additional embodiments, a portion of the catalyst is recycled to burner 350. For example, as Figure 1As shown, the catalyst delivery line 502 can transfer catalyst from the catalyst treatment section 300 (upstream of the oxygen treatment zone 370) back to the burner 350. Such recycle flow via the delivery line 502 can be used to control the catalyst density in the burner 350. For example, when a relatively large amount of catalyst is present in the second catalyst section (via line 508), the catalyst density in the burner 350 may be relatively low, and thus recycle of additional catalyst via line 502 can allow for better control of the catalyst density to maintain proper fluidization in the burner 350.

[0036] According to some embodiments, a portion of the re - combined catalyst stream is recycled to the burner 350 before entering the oxygen treatment zone 370. In such embodiments, the delivery line 502 can be downstream of the inlet of the delivery line 508 that delivers catalyst directly from the reactor section 200, such that the combination of the first catalyst section and the second catalyst section occurs upstream of the inlet of the delivery line 520. According to further embodiments, a portion of the first catalyst section is recycled to the burner 350 before entering the oxygen treatment zone 370. In such embodiments, the delivery line 502 can be upstream of the inlet of the delivery line 508 that delivers catalyst directly from the reactor section 200, such that only the first catalyst section is transferred into the delivery line 502.

[0037] In one or more embodiments, light olefins can be present in a “product stream” sometimes referred to as an “olefin - containing effluent” and include light olefins. This stream exits Figure 1 the reactor system and can subsequently be processed. As used in this disclosure, the term “light olefins” refers to one or more of ethylene, propylene, and butene. In further embodiments, the feed can contain ethylbenzene present in the product stream, and the ethylbenzene is converted to styrene, which is an embodiment of the olefin - containing material as described herein. The term butene includes any butene isomer, such as α - butene, cis - β - butene, trans - β - butene, and isobutene. In some embodiments, based on the total weight of the olefin - containing effluent, the olefin - containing effluent contains at least 30 wt% light olefins. By way of example, based on the total weight of the olefin - containing effluent, the olefin - containing effluent can 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. The olefin - containing effluent can also 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 subsequent separation steps.

[0038] In a non-limiting example, the reactor system 102 described herein can be used to produce light olefins from a hydrocarbon feed stream. Light olefins can be produced from various hydrocarbon feed streams by utilizing different reaction mechanisms. As described herein, light olefins can be produced by utilizing dehydrogenation reactions.

[0039] According to one or more embodiments, the reaction can be a dehydrogenation reaction. According to such embodiments, the hydrocarbon feed stream can comprise one or more of ethylbenzene, ethane, propane, n-butane, and isobutane. In one or more embodiments, the hydrocarbon feed stream can 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 ethylbenzene. In one or more embodiments, the hydrocarbon feed stream can 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 ethane. In additional embodiments, the hydrocarbon feed stream can 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 propane. In additional embodiments, the hydrocarbon feed stream can 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 n-butane. In additional embodiments, the hydrocarbon feed stream can 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 isobutane. In additional embodiments, the hydrocarbon feed stream can 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 sum of ethane, propane, n-butane, and isobutane.

[0040] In one or more embodiments, the dehydrogenation reaction can utilize gallium and / or platinum particulate solids as catalysts. In such embodiments, the particulate solids can comprise a gallium and / or platinum catalyst. As described herein, the gallium and / or platinum catalyst comprises gallium, platinum, or both. The gallium and / or platinum catalyst can be supported on an alumina or alumina-silica support and can optionally comprise potassium. Such gallium and / or platinum catalysts are disclosed in U.S. Patent No. 8,669,406, which is incorporated herein by reference in its entirety. However, it should be understood that other suitable catalysts can be utilized for the dehydrogenation reaction.

[0041] In one or more embodiments, the reaction mechanism can be dehydrogenation, followed by combustion (in the same chamber). In such embodiments, the dehydrogenation reaction can produce hydrogen as a byproduct, and the oxygen carrier material can contact the hydrogen and promote its combustion to form water. Examples of such reaction mechanisms are disclosed in WO 2020 / 046978, which are considered possible reaction mechanisms for the systems and methods described herein, and the teachings of which are incorporated herein by reference in their entirety.

[0042] Example

[0043] This example illustrates the change in dehydrogenation catalytic activity of a catalyst exposed to the combustion of a supplementary fuel. As described herein, the identification of the results of exposure to the combustion of a supplementary fuel can provide a theoretical basis for the usefulness of the systems described herein, where a portion of the catalyst bypasses the burner.

[0044] In a laboratory-scale fixed-bed reactor, propane dehydrogenation tests were conducted at ambient pressure using simulated reaction-combustion-regeneration (standard) cycles and reaction-regeneration (bypass) cycles. For each test, a 0.5 g catalyst sample was mixed with 1.0 g of inert silicon carbide and loaded into a quartz reaction tube. In the standard cycle, it includes reaction, combustion, and regeneration steps. First, at a reactor temperature of 625 °C, with a feed composition of 90 mol.% propane and 10 mol.% nitrogen, at a total flow rate of 51.38 standard cubic centimeters per minute (sccm) and a weight hourly space velocity (WHSV) of 10 h -1 of propane, the propane dehydrogenation reaction step was carried out for 60 seconds. Next, the reaction tube was purged under a helium flow and heated to 730 °C. Next, at a reactor temperature of 730 °C, with a feed composition of 2.5 mol% methane (balance air), at a total flow rate of 50 sccm and a WHSV of 0.1 h -1 of methane, the fuel combustion step was carried out for 180 seconds. Next, at a reactor temperature of 730 °C, with a feed composition of 100% air, the regeneration step was carried out at a flow rate of 40 sccm for 120 seconds. Next, the reaction tube was purged under a helium flow and cooled to 625 °C to start the next cycle. In the bypass cycle, each step was carried out similarly to the standard cycle except that the fuel combustion step was skipped. That is, after the reaction step and purging under helium, the regeneration step was carried out. For each propane dehydrogenation reaction step, the reactor effluent was analyzed by gas chromatography (GC) at a 30-second run time, and the propane conversion was calculated from the product gas concentrations based on carbon atoms. The catalyst used for the test contained platinum and gallium on an alumina support.

[0045] All standard cycles (including exposure to methane combustion) were tested, where the propane conversion data for each subsequent cycle was inFigure 2 is shown. It can be seen that the propane conversion rate steadily decreases during the cycle.

[0046] At cycles 20, 40, and 60, another test was performed on all standard cycles except for the bypass cycle. The data for this experiment are provided in Figure 3 which shows a significant increase in propane conversion rate after the bypass cycle (indicating greater dehydrogenation catalytic activity). Thus, by analogy, the catalyst that bypasses the burner in the embodiments disclosed in the present invention will generally have greater activity, even when both are exposed to the regeneration oxygen treatment.

[0047] The present disclosure includes several aspects. One aspect is a method for forming a dehydrogenation product, the method comprising: reacting a feed stream in a reactor in the presence of a catalyst by a dehydrogenation reaction 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; transferring the first catalyst portion to a burner, wherein the first catalyst portion is heated in the burner by combusting a supplementary fuel; transferring the first catalyst portion out of the burner, and combining the first catalyst portion downstream of the burner with the second catalyst portion to form a recombined catalyst stream such that the second catalyst portion bypasses the burner; transferring the recombined catalyst stream through an oxygen treatment zone; and transferring the recombined catalyst stream to the reactor.

[0048] Another aspect is any single one of the above aspects or a combination of the above aspects, 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.

[0049] Another aspect is any single one of the above aspects or a combination of the above aspects, 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.

[0050] Another aspect is any single one of the above aspects or a combination of the above aspects, wherein the dehydrogenation reaction forms coke on the catalyst.

[0051] Another aspect is any single one of the above aspects or a combination of the above aspects, wherein at least a portion of the coke is combusted in the burner.

[0052] Another aspect is any single one of the above aspects or a combination of the above aspects, wherein the supplementary fuel comprises hydrogen, methane, ethane, propane, or natural gas.

[0053] Another aspect is any single one of the above aspects or a combination of the above aspects, wherein the product stream comprises one or more of ethylene, propylene, butene, or styrene.

[0054] Another aspect is any single one of the above aspects or a combination of the above aspects, wherein the product stream contains at least 30% by weight of ethane, propane, butane, or ethylbenzene.

[0055] Another aspect is any single one of the above aspects or a combination of the above aspects, wherein the fluidization regime in the oxygen treatment zone is bubbling bed fluidization.

[0056] Another aspect is any single one of the above aspects or a combination of the above aspects, wherein the first catalyst portion is deactivated for dehydrogenation activity in the burner and then reactivated for dehydrogenation activity in the oxygen treatment zone.

[0057] Another aspect is any single one of the above aspects or a combination of the above aspects, wherein the recombined catalyst stream is passed through a stripping zone downstream of the oxygen treatment zone.

[0058] Another aspect is any single one of the above aspects or a combination of the above aspects, wherein the catalyst contains gallium and platinum.

[0059] Another aspect is any single one of the above aspects or a combination of the above aspects, wherein the catalyst further contains an alumina support.

[0060] Another aspect is any single one of the above aspects or a combination of the above aspects, 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.

[0061] Another aspect is any single one of the above aspects or a combination of the above aspects, wherein a portion of the recombined catalyst stream or a portion of the first catalyst portion is recycled to the burner before entering the oxygen treatment zone.

[0062] In one or more embodiments, streams etc. are described as being "passed" from one system component to another system component. It should be understood that passing can describe direct passing (wherein the stream passes directly between the two system components) or indirect passing (wherein the stream passes between the two system components through one or more intermediate system components or pipelines).

[0063] 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 the technology. Since those skilled in the art can make modifications, combinations, sub - combinations, and variations of the disclosed embodiments that incorporate the spirit and substance of the technology disclosed herein, the technology should be construed to include all things within the scope of the appended claims and their equivalents. Additionally, although some aspects of the present disclosure may be identified herein as being preferred or particularly advantageous, the present disclosure is not limited to these aspects.

[0064] It should be noted that the various details described in this disclosure should not be construed as implying that these details pertain to elements that are essential components of the various embodiments described in this disclosure, even in cases where a particular element is shown in each of the accompanying drawings of this specification. Unless expressly stated otherwise, the features disclosed and described herein should not be construed as "essential." Embodiments contemplated by this technology include those that include some or all of the features of the appended claims.

[0065] In relevant cases, where 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.

[0066] It should be understood that in some embodiments, the composition ranges of chemical components in a stream or reactor should be understood to contain mixtures of isomers of that component. For example, a specified composition range for butene can include mixtures of the various isomers of butene. It should be understood that the examples provide composition ranges for various streams, and the total amount of isomers of a particular chemical composition can constitute a range.

[0067] It should be noted that one or more of the following claims and detailed description utilize the terms "where" or "wherein" as transitional phrases. For purposes of defining this technology, it should be noted that this term is introduced in the claims as an open transitional phrase that is used to introduce a recitation of a series of characteristics of a structure and should be interpreted in a manner similar to the more commonly used open preamble term "comprising."

[0068] It should be understood that any two quantitative values assigned to a characteristic can constitute a range of that characteristic, and all combinations of ranges formed by all the recited quantitative values of a given characteristic are contemplated in this disclosure. In cases where multiple ranges of quantitative values are provided, these ranges can be combined to form a broader range, which is contemplated in the embodiments described herein.

[0069] As understood in the context of the terms used herein, the term "transfer" can include directly transferring a substance between two parts of the disclosed system and, in some cases, means indirectly transferring a substance between two parts of the disclosed system. For example, indirect transfer can include steps in which the substance transfer occurs through an intermediate separation device, valve, sensor, etc.

Claims

1. A method for forming a dehydrogenation product, the method comprising: React a feed stream in a reactor in the presence of a catalyst by a dehydrogenation reaction to form a dehydrogenation product; Separate at least a portion of the product stream from the catalyst; Separate the catalyst into at least a first catalyst portion and a second catalyst portion; Transfer the first catalyst portion to a combustor, wherein the first catalyst portion is heated in the combustor by combusting a make-up fuel; Transfer the first catalyst portion out of the combustor and combine the first catalyst portion downstream of the combustor with the second catalyst portion to form a recombined catalyst stream such that the second catalyst portion bypasses the combustor; Transfer the recombined catalyst stream through an oxygen treatment zone; And Transfer the recombined catalyst stream to the reactor.

2. The method according to 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. The method according to 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 7:

3.

4. The method according to any one of the preceding claims, wherein the dehydrogenation reaction forms coke on the catalyst.

5. The method according to claim 4, wherein at least a portion of the coke is burned in the burner.

6. The method according to any one of the preceding claims, wherein the supplementary fuel comprises hydrogen, methane, ethane, propane or natural gas.

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

8. The method according to any one of the preceding claims, wherein the product stream comprises at least 30% by weight of ethane, propane, butane or ethylbenzene.

9. The method according to any one of the preceding claims, wherein the fluidization regime in the oxygen treatment zone is bubbling bed type fluidization.

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

11. The method according to any one of the preceding claims, wherein the recombined catalyst flow is passed through a stripping zone downstream of the oxygen treatment zone.

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

13. The method according to claim 12, wherein the catalyst further comprises an alumina support.

14. The method according to any one of the preceding claims, wherein after the dehydrogenation reaction, combustion of the hydrogen product of the dehydrogenation reaction occurs and an oxygen-carrying material is present in the reactor.

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

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