Method for producing light olefins

Abstract

A method for forming light olefins in a reactor system may include reacting a feed stream in the presence of particulate solids in a reactor to form a product stream. The reaction may form coke on the particulate solids. The method may include transferring the particulate solids to a regenerator and burning at least a portion of the coke to heat the particulate solids; mixing air and an auxiliary fuel upstream of the regenerator to form a gas mixture and transferring the gas mixture through a distributor to the regenerator; burning the auxiliary fuel in the regenerator to heat the particulate solids; and transferring the heated particulate solids from the regenerator to the reactor. The concentration of the auxiliary fuel in the gas mixture may be less than 80% of the lower explosive limit of the auxiliary fuel in the gas mixture, and the heat generated by burning the coke and auxiliary fuel may be sufficient to maintain thermal balance in the reactor system.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Application No. 63 / 428,494, 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 catalytic chemical conversion. [Background technology]

[0003] Many chemicals can be produced by processes that use particulate solids, such as solid particulate catalysts. During these processes, the particulate solids can become "spent" and become less active in subsequent reactions. Furthermore, endothermic processes require heat, and the "spent" catalyst must be reheated. Therefore, the spent particulate solids can be transferred to a regeneration unit to be reheated and regenerated, increasing the activity of the particulate solids for use in subsequent reactions. Following regeneration in the regeneration unit, the regenerated particulate solids can be returned to the reactor for use in subsequent reactions. Summary of the Invention

[0004] There is a need for an improved method of regenerating particulate solids for use in the production of light olefins. The method of regenerating particulate solids can include burning a supplemental fuel to heat the catalyst. The supplemental fuel and air may be introduced into the combustor through separate distributors. Coke can form on the metal surfaces of the distributor used to inject the supplemental fuel into the combustor. Coke formation on the distributor can clog the distributor, requiring the catalyst regeneration system to be shut down. Furthermore, because combustor vessels are large and can operate at extremely high temperatures, the mechanical constraints of operating a fuel gas distributor across the entire cross-section of the vessel can limit the size of the vessel that can be constructed.

[0005] One or more of the methods disclosed herein for forming light olefins can address this issue. In one or more embodiments, air and auxiliary fuel can be mixed upstream of the combustor. This gas mixture can be injected into the combustor through a single distributor, which can reduce coke formation on the distributor and, for vessels operating at temperatures between 750°C and 915°C, can eliminate the need to operate the distributor across the entire cross section of the vessel. The concentrations of the auxiliary fuel and air in the gas mixture can be controlled so that the proportion of the auxiliary fuel in the gas mixture is below the lower explosive limit of the auxiliary fuel. This can reduce the risk of the gas mixture combusting before it is injected into the combustor.

[0006] According to one or more embodiments disclosed herein, a method for forming light olefins in a reactor system including a reactor and a regenerator may include reacting a feed stream in the presence of particulate solids in the reactor to form a product stream. The reaction may form coke on the particulate solids, and the reaction may be endothermic. The method may include transferring the particulate solids to a regenerator and burning at least a portion of the coke to heat the particulate solids. The method may include mixing air and an auxiliary fuel upstream of the regenerator to form a gas mixture and transferring the gas mixture through a distributor to the regenerator. The method may include burning the auxiliary fuel in the regenerator to heat the particulate solids and transferring the heated particulate solids from the regenerator to the reactor. The concentration of the auxiliary fuel in the gas mixture may be less than 80% of the lower explosive limit of the auxiliary fuel in the gas mixture, and the heat generated by burning at least a portion of the coke and the auxiliary fuel may be sufficient to maintain thermal balance in the reactor system. [Brief explanation of the drawings]

[0007] The following detailed description of certain embodiments of the present disclosure can be best understood when read in conjunction with the following drawings, in which like structure is indicated with like reference numerals and in which: [Figure 1] 1 illustrates a schematic diagram of a reactor system including a reactor section and a regenerator section, according to one or more embodiments disclosed herein. [Figure 2] 1A and 1B illustrate schematic cross-sectional views of a plate grid distributor according to one or more embodiments disclosed herein.

[0008] It should be understood that the drawings are schematic in nature and do not include some components of fluid catalytic reactor systems commonly used in the art, such as, without limitation, temperature transmitters, pressure transmitters, flow meters, pumps, valves, etc. It will be appreciated that these components are within the spirit and scope of the disclosed embodiments. However, operating components such as those described in this disclosure may be added to the embodiments described in this disclosure.

[0009] Reference will now be made in more detail to various embodiments, some of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. DETAILED DESCRIPTION OF THE INVENTION

[0010] As described herein, a method for producing light olefins may include reacting a feed stream in the presence of particulate solids to form a product stream. The reaction may result in the formation of coke on the particulate solids, which can be regenerated by burning the coke and heating the particulate solids. The method may also include mixing a supplemental fuel with air to form a gas mixture, transferring the gas mixture to a regenerator, and burning the supplemental fuel in the regenerator to heat the particulate solids. The heated particulate solids may be returned to the reactor. Such methods may utilize systems having particular features, such as specific orientations of system components. One particular embodiment disclosed in detail herein is shown in FIG. 1. However, it should be understood that the principles disclosed and taught herein may be applicable to other systems utilizing different system components oriented in different ways or different reaction schemes utilizing various catalyst compositions.

[0011] In a non-limiting example, the reactor system 102 described herein can be utilized to produce light olefins from a hydrocarbon feed stream. Light olefins can be produced from a wide variety of hydrocarbon feed streams by utilizing different reaction mechanisms. For example, light olefins can be produced by at least dehydrogenation reactions, cracking reactions, dehydration reactions, and methanol-to-olefins reactions. These reaction types can utilize different feed streams and different particulate solids to produce light olefins. It should be understood that when "particulate solids" are referred to herein, it can equally refer to the catalysts referred to with respect to the system of FIG. 1.

[0012] Referring now to FIG. 1 , an exemplary reactor system 102 that may be suitable for use with the methods described herein is illustrated schematically. However, it should be understood that other reactor system configurations may be suitable for the methods described herein. The reactor system 102 generally comprises multiple system components, such as a reactor section 200 and / or a catalyst treatment section 300. 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 reactions occur. The reactor section 200 includes a reactor 202, which may include a downstream reactor section 230 and an upstream reactor section 250. According to one or more embodiments, as shown in FIG. 1 , the reactor section 200 may further comprise a catalyst separation section 210 that serves to separate the catalyst from the chemical products formed in the reactor 202. Also, as used herein, the catalyst treatment section 300 generally refers to the portion of the reactor system 102 where the catalyst is treated in some manner, such as by combustion. Catalytic treater 300 may include a combustor 350 and a riser 330, and may optionally include a catalyst separation section 310. In some embodiments, the catalyst may be regenerated in catalytic treater 300 by burning contaminants, such as coke. In embodiments, the catalyst may be heated in catalytic treater 300. If coke or another combustible material does not form on the catalyst, or if the amount of coke formed on the catalyst is insufficient to burn to heat the catalyst to the desired temperature, a supplemental fuel may be utilized to heat the catalyst in catalytic treater 300. In one or more embodiments, catalyst separation section 210 may be in fluid communication with combustor 350 (e.g., via water tower 426), and catalyst separation section 310 may be in fluid communication with upstream reactor section 250 (e.g., via water tower 424 and transfer riser 430).

[0013] As described with respect to FIG. 1 , the feed stream can enter the transfer riser 430, and the product stream can exit the reactor system 102 via the pipe 420. According to one or more embodiments, the reactor system 102 can be operated by supplying a chemical feedstock (e.g., in a feedstream) and a fluidized catalyst to the upstream reactor section 250. The chemical feed contacts the catalyst in the upstream reactor section 250, and each flows upward into and through the downstream reactor section 230 to produce a chemical product. The chemical product and catalyst exit the downstream reactor section 230 and may be sent to the separation device 220 in the catalyst separation section 210, where the catalyst is separated from the chemical product and the chemical product is transferred from the catalyst separation section 210. The separated catalyst is sent from the catalyst separation section 210 to the combustor 350. In the combustor 350, the catalyst can be processed, for example, by combustion. For example, without limitation, the catalyst may be decoked and / or a supplemental fuel may be burned to heat the catalyst. The catalyst then exits combustor 350 and passes through riser 330 to end-of-riser separator 378, where gas and solid components from riser 330 are at least partially separated. The vapor and remaining solids are transferred to secondary separator 320 in catalyst separation section 310, where the remaining catalyst is separated from gases from the catalytic process (e.g., gases released by the combustion of spent catalyst or supplemental fuel). The separated catalyst is then sent from catalyst separation section 310 via distribution tower 424 and transfer riser 430 to upstream reactor section 250, where it is further utilized in catalytic reactions. Thus, the catalyst may be circulated between reactor section 200 and catalytic treatment section 300 during operation. In general, the processed chemical streams, including the feed stream and product stream, may be gaseous, and the catalyst may be a fluidized particulate solid.

[0014] Additionally, as described herein, the structural features of reactor section 200 and regeneration section 300 may be similar or identical in some respects. For example, reactor section 200 and regeneration section 300 each include a reaction vessel (i.e., upstream reactor vessel section 250 of reactor section 200 and combustor 350 of regeneration section 300), a riser (i.e., riser 230 of reactor section 200 and riser 330 of regeneration section 300), and a particulate solids separation section (i.e., particulate solids separation section 210 of reactor section 200 and particulate solids separation section 310 of regeneration section 300). Because many of the structural features of reactor section 200 and regeneration section 300 may be similar or identical in some respects, similar or identical portions of reactor section 200 and regeneration section 300 are provided with reference numbers having the same last two digits throughout this disclosure, and it should be understood that a disclosure regarding one portion of reactor section 200 may be applicable to similar or identical portions of regeneration section 300, and vice versa.

[0015] According to one or more embodiments described herein, the reactor section 200 may comprise an upstream reactor section 250, a transfer section 258, and a downstream reactor section 230, such as a riser. The transfer section 258 may connect the upstream reactor section 250 with the downstream reactor section 230. According to one or more embodiments, the upstream reactor section 250 and the downstream reactor section 230 may each have a substantially constant cross-sectional area, while the transfer section 258 may be tapered and not have a constant cross-sectional area. As used herein, unless otherwise specified, "cross-sectional area" refers to the area of ​​a cross section of a portion of a reactor component that lies in a plane that is substantially perpendicular to the general direction of flow of reactants and / or products. For example, in FIG. 1, the cross-sectional areas of the upstream reactor section 250, the transfer section 258, and the downstream reactor section 230 are in the plane defined by the horizontal direction and the direction into the page (perpendicular to the direction of fluid movement, i.e., vertically upward in FIG. 1).

[0016] 1, the upstream reactor section 250 may be located below the downstream reactor section 230. Such a configuration may be referred to as an upflow configuration in the reactor 202.

[0017] As described herein, the upstream reactor section 250 can comprise a vessel, drum, barrel, vat, or other container suitable for a given chemical reaction. In one or more embodiments, the shape of the upstream reactor section 250 can be generally cylindrical (i.e., having a substantially circular cross-sectional shape) or non-cylindrical, such as a prismatic shape having a triangular, square, pentagonal, hexagonal, octagonal, elliptical, or other polygonal cross-sectional shape, or a closed curved shape, or a combination thereof. As used throughout this disclosure, the upstream reactor section 250 can generally comprise a metal frame and can further comprise a refractory lining or other material utilized to protect the metal frame and / or control process conditions. As shown in FIG. 1 , the upstream reactor section 250 can include a catalyst inlet port 252 in the lower reactor section, which defines a connection between the transfer riser 430 and the upstream reactor section 250.

[0018] 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 this disclosure. It should be understood that a compositional range of a chemical component in a composition should, in some embodiments, be understood to contain a mixture of isomers of that component. In additional embodiments, a chemical compound may exist in other forms, such as derivatives, salts, hydroxides, etc. Generally, the "inlet port" and "outlet port" of any system unit of the reactor system 102 described herein refer to an opening, hole, channel, aperture, gap, or other similar mechanical feature within the system unit. For example, an inlet port allows for the inflow of material into a particular system unit, and an outlet port allows for the outflow of material from a particular system unit. Generally, an outlet port or inlet port defines an area of ​​the system apparatus of the reactor system 102 to which a pipe, conduit, tube, hose, transfer line, or similar mechanical feature is attached, or a portion of the system apparatus to which another system unit is directly attached. Although inlet and outlet ports may be described herein functionally in operation, they may have similar or identical physical characteristics, and their respective functions in an operational system should not be construed as limiting their physical structure.

[0019] The upstream reactor section 250 can be connected to a transfer riser 430 that can provide treated catalyst and / or reaction chemicals in a feed stream to the reactor section 200 during operation. The treated 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 can enter the transfer riser 430 directly from the catalyst separation section 210 via a distributor 422, where it enters the upstream reactor section 250. Catalyst may also be fed directly to the upstream reactor section 250 via 422. This catalyst may be slightly deactivated but may still, in some embodiments, be suitable for reaction in the upstream reactor section 250. As used herein, "deactivated" can refer to a catalyst that is contaminated with materials such as coke or that is at a lower than desired temperature. Regeneration can remove contaminants such as coke, increase the temperature of the catalyst, or both.

[0020] 1 , reactor section 200 can include a downstream reactor section 230 that serves to transfer reactants, products, and / or catalyst from upstream reactor section 250 to catalyst separation section 210. In one or more embodiments, downstream reactor section 230 can be generally cylindrical (i.e., having a substantially circular cross-sectional shape) or non-cylindrical, such as a prismatic shape having a triangular, square, pentagonal, hexagonal, octagonal, elliptical, or other polygonal cross-sectional shape, or a closed curve, or a combination thereof. As used throughout this disclosure, downstream reactor section 230 can generally include a metal frame and can further include a refractory lining or other material utilized to protect the metal frame and / or control process conditions.

[0021] According to some embodiments, the downstream reactor section 230 can include an external riser section 232 and an internal riser section 234. As used herein, the "external riser section" refers to the portion of the riser that is outside the catalyst separation section, and the "internal riser section" refers to the portion of the riser that is within the catalyst separation section. For example, in the embodiment shown in Figure 1, the internal riser section 234 of the reactor section 200 can be located within the catalyst separation section 210, while the external riser section 232 can be located outside the catalyst separation section 210.

[0022] 1 , upstream reactor section 250 can be connected to downstream reactor section 230 via transfer section 258. Upstream reactor section 250 can generally have a larger cross-sectional area than downstream reactor section 230. Transfer section 258 can taper from the cross-sectional size of upstream reactor section 250 to the cross-sectional size of downstream reactor section 230 such that transfer section 258 projects inward from upstream reactor section 250 toward downstream reactor section 230.

[0023] In some embodiments, for example, where the upstream reactor section 250 and the downstream reactor section 230 have similar cross-sectional shapes, the transition section 258 may be shaped as a frustum. For example, in an embodiment of the reactor section 200 including a cylindrical upstream reactor section 250 and a cylindrical downstream reactor section 230, the transition section 258 may be shaped as a frustum of a cone. However, it should be understood that a wide variety of upstream reactor section 250 shapes connecting various shapes and sizes of the upstream reactor section 250 and the downstream reactor section 230 are contemplated herein.

[0024] During operation, catalyst may travel upward (from the upstream reactor section 250) through the downstream reactor section 230 and into the separator 220. Separated vapor may be removed from the reactor system 102 via a pipe 420 at the gas outlet port 216 of the catalyst separation section 210. According to one or more embodiments, the separator 220 may be a cyclone separation system that may include two or more stages of cyclone separation. In embodiments in which the separator 220 includes more than one cyclone separation stage, the first separator into which the fluidized stream enters is referred to as the primary cyclone separator. The fluidized effluent from the primary cyclone separator may enter a secondary cyclone separator for further separation. Primary cyclone separators may include, for example, primary cyclones 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). Primary cyclones are 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. Some separation systems utilizing a primary cyclone as a primary cyclonic separator employ 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 cyclonic separator may be used in embodiments of the present invention.

[0025] According to one or more embodiments, following separation from the vapor in separator 220, the catalyst may generally travel through stripper 224 to catalyst outlet port 222, where it is transferred out of reactor section 200 via water column 426 to catalyst treatment section 300. Optionally, the catalyst can also be transferred directly back to upstream reactor section 250 via water column 422. Alternatively, the catalyst can be premixed with the treated catalyst in transfer riser 430.

[0026] As will be described in detail according to the embodiment of FIG. 1 , according to one or more embodiments, the catalyst may be treated by one or more of the following steps: transferring the catalyst from the reactor 202 to a combustor 350; burning a supplemental fuel source in the combustor 350 to heat the catalyst; and transferring the heated catalyst from the combustor 350 to the reactor 202.

[0027] 1, the combustor 350 of the catalytic treater 300 may include one or more lower reactor section inlet ports 352 and may be in fluid communication with the riser 330. The combustor 350 may be in fluid communication with the catalyst separation section 210 via a water column 426, which may deliver spent catalyst from the reactor section 200 to the catalytic treater 300 for regeneration.

[0028] In one or more embodiments, a gas mixture including air and the auxiliary fuel may travel to the combustor 350 through the lower reactor inlet port 352. The gas mixture may be formed by mixing the air and the auxiliary fuel upstream of the combustor 350. In embodiments, the air and the auxiliary fuel may mix in a static mixer 450. The static mixer 450 may be any static mixer suitable for mixing gases. For example, the static mixer may include a housing and one or more baffles disposed within the housing. In embodiments, the one or more baffles may be helical shaped. In embodiments, the static mixer may be a plate-type static mixer. Without intending to be bound by theory, it is believed that the structure of the static mixer creates turbulence that mixes the fluids flowing through the static mixer. The gas mixture may travel from the static mixer 450 to the combustor 350 through a conduit 428. In embodiments, air may travel to static mixer 450 through conduit 452, and supplemental fuel may travel to static mixer 450 through conduit 454. In one or more embodiments, the supplemental fuel may include hydrogen, methane, natural gas, ethane, propane, or any gas that produces heat when combusted. In one or more embodiments, the air may be enriched with oxygen. For example, enriched air may include greater than 21 mole percent oxygen, or between 21 mole percent oxygen and 40 mole percent oxygen.

[0029] In one or more embodiments, the fuel gas distributor can inject auxiliary fuel into the air upstream of the static mixer in conduit 452. Without intending to be bound by theory, this may result in a more uniform distribution of the auxiliary fuel in the air as it travels to static mixer 450. Referring now to FIG. 2 , the fuel gas distributor may be a plate-grid distributor 900. In an embodiment, plate-grid distributor 900 may include a plate 910 and a refractory lining 920 downstream of plate 910. Plate-grid distributor 900 may include multiple injection points (injection points 930 and 940 shown in FIG. 2 ). In the embodiment shown in FIG. 2 , injection point 930 is configured to allow both air and auxiliary fuel to pass through injection point 930. The auxiliary fuel may pass through tube 932, and air may pass through the annular spaces between tube 934 and tube 932 and between plate 910 and tube 932. It should be understood that the tube 932 can be connected to a supplemental fuel source (not shown). In the embodiment shown in Figure 2, the injection point 940 is configured to allow air to pass through the injection point 940.

[0030] In some embodiments, the fuel gas and air may pass through each injection point of the distributor. In some embodiments, the fuel gas and air may pass through separate injection points. In one or more embodiments, there may be an air injection point for each fuel gas. For example, there may be more than one air injection point for each fuel gas injection point. For example, there may be 2 to 10 air injection points for each fuel gas injection point. Without intending to be bound by theory, passing the fuel gas and air through each injection point may provide good fuel gas distribution, but may result in a system that is relatively complex to design and maintain. Similarly, a distributor that includes a fuel gas injection point for each air injection point may provide good fuel gas distribution, but may result in a system that is relatively complex to design and maintain. On the other hand, including multiple air injection points per fuel gas injection point may reduce the complexity of the fuel gas distributor while maintaining satisfactory fuel gas distribution.

[0031] Without intending to be bound by theory, and again referring to FIG. 1 , mixing the air and auxiliary fuel upstream of the combustor 350 can provide a more homogeneous mixture of the auxiliary fuel and air within the combustor 350 than introducing the auxiliary fuel and the air separately into the combustor. The homogeneous mixture of air and auxiliary fuel can ensure that the stoichiometric ratio of oxygen to fuel is sufficient locally to combust the fuel when it enters the combustor 350. The homogeneous mixture of air and auxiliary fuel can contribute to uniform combustion of the fuel within the combustor 350, thereby reducing the formation of hot spots within the combustor 350. Furthermore, if the air and auxiliary fuel are not mixed homogeneously, localized regions may exist where the lower explosive limit of the fuel is exceeded.

[0032] In an embodiment, the gas mixture may be introduced into the combustor 350 through a single distributor. The distributor may include multiple nozzles operable to uniformly distribute the gas mixture within the combustor 350. A suitable fuel gas distributor is described in U.S. Pat. No. 9,889,418, which is incorporated herein by reference in its entirety. While not intending to be bound by theory, introducing the gas mixture through a single distributor may reduce the possibility of coke buildup on the distributor. If the supplemental fuel and air are introduced into the combustor 350 separately through their own distributors, coke may form on the fuel gas distributor under the high temperature conditions of the combustor 350. Such coke buildup may clog the distributor, resulting in uneven introduction of the supplemental fuel into the combustor 350 and even requiring the reactor system 102 to be shut down. While not intending to be bound by theory, when a plate-grid distributor is used, insulating refractory material may be installed above the distributor to control the mixture of air and supplemental fuel at a desired temperature. The refractory may insulate the bottom of the distributor so that the bottom is at the same temperature as the gas flowing through the distributor. The pipes flowing into the distributor may be at least partially covered by a thin, high-density refractory material, which may be a less effective insulator than the refractory installed on top of the distributor.

[0033] In one or more embodiments, the volumetric concentration of the supplemental fuel in the gas mixture when thoroughly mixed can be less than the lower explosive limit of the supplemental fuel. As described herein, the "lower explosive limit" (LEL) of a gas is the lowest concentration of that gas in air that can burn in the presence of an ignition source, such as an arc, flame, or heat. For example, the concentration of the supplemental fuel in the gas mixture can be 90% or less, 85% or less, 80% or less, 75% or less, 70% or less, 65% or less, 60% or less, 50% or less, 45% or less, or 40% or less of the supplemental fuel's LEL. In one or more embodiments, the concentration of the supplemental fuel in the gas mixture can be between 25% and 90% of the LEL. For example, the concentration of the auxiliary fuel in the gas mixture may be between 25% and 90%, 30% and 90%, 35% and 90%, 40% and 90%, 45% and 90%, 50% and 90%, 55% and 90%, 60% and 90%, 65% and 90%, 70% and 90%, 75% and 90%, 80% and 90%, 85% and 90%, 25% and 85%, 25% and 80%, 25% and 75%, 25% and 70%, 25% and 65%, 25% and 60%, 25% and 55%, 25% and 50%, 25% and 45%, 25% and 40%, 25% and 35%, 25% and 30%, or any combination or subset of ranges thereof.

[0034] In general, the LEL of a gas can change as temperature, pressure, and oxygen concentration change. For example, the LEL decreases as temperature increases, the LEL decreases as pressure increases, and the LEL decreases as oxygen concentration increases. In one or more embodiments, the air and auxiliary fuel may be mixed at ambient conditions, and the LEL of the gas mixture may be determined based on ambient conditions, such as atmospheric pressure and a temperature of about 25°C. In embodiments, the gas mixture may be injected into the combustor at approximately ambient temperature. In one or more embodiments, the air and auxiliary fuel may be mixed at a temperature greater than ambient temperature or a pressure greater than ambient pressure, or both. For example, the air and auxiliary fuel may be mixed at a temperature between ambient and 400°C, between ambient and 300°C, between ambient and 200°C, or between ambient and 100°C. In such embodiments, the LEL at a mixed condition can be mathematically predicted. The LEL can be predicted and controlled by a control system that includes sensors, such as temperature sensors, pressure sensors, and analyzers capable of measuring the concentration of the fuel gas or oxygen. The control system can automatically adjust the air and fuel gas flows to prevent the air and fuel gas mixture from exceeding the LEL target.

[0035] In one or more embodiments, the gas mixture may be heated between the static mixer 450 and the combustor 350. For example, the gas mixture may be heated before traveling to the regenerator via a distributor. In such embodiments, the concentration of the supplemental fuel in the gas mixture may be well below the LEL at ambient conditions, and the concentration of the supplemental fuel in the gas mixture may remain below the LEL after the gas mixture is heated. In one or more embodiments, the gas mixture may be heated to a temperature of 800°C or less. For example, the gas mixture may be heated to a temperature of 800°C, 700°C, 600°C, 500°C, or 400°C or less. In embodiments, the gas mixture may be heated to a temperature of 400°C to 800°C, 500°C to 800°C, 600°C to 800°C, 700°C to 800°C, 400°C to 700°C, 400°C to 600°C, 400°C to 500°C, or any combination or subset of these ranges. In embodiments, the gas mixture may be heated to a temperature such that the concentration of the auxiliary fuel is 80% or less of the LEL. For example, the gas mixture may be heated to a temperature such that the concentration of the auxiliary fuel is 80% or less of the LEL, 75% or less of the LEL, 70% or less of the LEL, 65% or less of the LEL, or 60% or less of the LEL. In embodiments, the gas mixture may be heated to a temperature such that the autoignition temperature of the auxiliary fuel is less than or equal to the autoignition temperature of the auxiliary fuel. While not intending to be bound by theory, preheating the gas mixture can reduce the amount of auxiliary fuel required and the amount of oxygen required to combust the auxiliary fuel. This may allow for the use of smaller process equipment.

[0036] Without intending to be bound by theory, maintaining the concentration of the supplemental fuel in the gas mixture below the LEL of the supplemental fuel significantly reduces the risk of the gas mixture igniting before the gas mixture is introduced into the combustor 350. Furthermore, the risk of the gas mixture exploding is also reduced. Reducing the risk of the gas mixture exploding or burning outside of the combustor 350 is desirable because this could pose a safety issue, damage system components, or require the reactor system 102 to be shut down.

[0037] In one or more embodiments, the catalyst may be heated by burning coke and auxiliary fuel in combustor 350. The heated catalyst may then be transferred to reactor 250 to provide heat to the reactor. In one or more embodiments, the heat generated by burning the coke and auxiliary fuel may be sufficient to maintain the heat balance of the reactor. In one or more embodiments, burning the coke and auxiliary fuel in combustor 350 may be the only means for heating the catalyst.

[0038] In embodiments, light olefins may be produced by one or more endothermic reactions. As described herein, an "endothermic reaction" refers to a chemical process in which the enthalpy or internal energy of a system increases, resulting in the system absorbing heat energy from its surroundings. Without intending to be bound by theory, when an endothermic reaction occurs in reactor 250, heat energy may be absorbed from the catalyst entering reactor 250, such that the catalyst exiting reactor 250 may have a lower temperature than the catalyst entering reactor 250. Therefore, a catalyst may be heated in combustor 350 such that the catalyst can provide sufficient heat to drive the endothermic reactions occurring in reactor 250 and maintain the thermal balance of system 102.

[0039] In one or more embodiments, additional supplemental fuel may be required to heat the catalyst. In such embodiments, the reactor 350 may include a second distributor for injecting the supplemental fuel into the combustor. The second distributor may be any suitable means for injecting the supplemental fuel into the reactor.

[0040] In a non-limiting example, the reactor system 102 described herein can be utilized to produce light olefins from a hydrocarbon feed stream. Light olefins can be produced from a wide variety of hydrocarbon feed streams by utilizing different reaction mechanisms. In one or more embodiments, light olefins can be produced by one or more endothermic reactions. For example, light olefins can be produced by endothermic reactions, including, but not limited to, dehydrogenation reactions, cracking reactions, dehydration reactions, and methanol-to-olefins reactions. These reaction types can utilize different feed streams and different particulate solids to produce light olefins. It should be understood that when "catalysts" are referred to herein, they can equally refer to the particulate solids referred to with respect to the system of FIG. 1.

[0041] 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.

[0042] 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, the 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.

[0043] 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 and form water. The oxygen carrier material may include one or more transition metal oxides. According to one or more embodiments, the one or more transition metal oxides may be redox-active transition metal oxides. Redox-active transition metal oxides include binary, ternary, or other mixed metal oxides that may undergo reduction in the presence of a reducing agent (e.g., hydrogen) and oxidation in the presence of an oxidizing agent (e.g., oxygen or air). In some embodiments, the redox-active transition metal oxide may be selected from Mn2O3, Fe2O3, Co3O4, CuO, (LaSr)CoO3, (LaSr)MnO3, Mg6MnO8, MgMnO3, MnO2, Fe3O4, Mn3O4, and Cu2O. In some embodiments, the oxygen carrier material may be a solid. In certain embodiments, the oxygen carrier material may be a pulverized solid or powder. Examples of such reaction mechanisms contemplated as possible reaction mechanisms for the systems and methods described herein are disclosed in WO 2020 / 046978 and WO 2019 / 048391, the teachings of which are incorporated herein by reference in their entireties.

[0044] According to one or more embodiments, the reaction may be a cracking reaction. According to such embodiments, the hydrocarbon feed stream may comprise one or more of naphtha, n-butane, or i-butane. According to 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% naphtha. 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 naphtha, n-butane, and i-butane.

[0045] In one or more embodiments, the cracking reaction may utilize one or more zeolites as a catalyst. In such embodiments, the particulate solid may include one or more zeolites. In some embodiments, the one or more zeolites utilized in the cracking reaction may include ZSM-5 zeolite. However, it should be understood that other suitable catalysts may be utilized to carry out the cracking reaction. For example, suitable commercially available catalysts may include Intercat Super Z Excel or Intercat Super Z Exceed. In additional embodiments, the cracking catalyst may include platinum in addition to the catalytically active material. For example, the cracking catalyst may include 0.001% to 0.05% by weight of platinum. The platinum may be sprayed as platinum nitrate and calcined at a high temperature, such as about 700°C. Without being bound by theory, it is believed that the addition of platinum to the catalyst may allow for easier combustion of auxiliary fuels, such as methane.

[0046] According to one or more embodiments, the reaction may be a dehydration reaction. According to such embodiments, the hydrocarbon feed stream may comprise one or more of ethanol, propanol, or butanol. According to 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% ethanol. 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% propanol. 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% butanol. 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 ethanol, propanol, and butanol.

[0047] In one or more embodiments, the dehydration reaction may utilize one or more acid catalysts. In such embodiments, the particulate solid may include one or more acid catalysts. In some embodiments, the one or more acid catalysts utilized in the dehydration reaction may include a zeolite (such as ZSM-5 zeolite), alumina, an amorphous aluminosilicate, an acid clay, or a combination thereof. For example, commercially available alumina catalysts that may be suitable, according to one or more embodiments, include SynDol (available from Scientific Design Company), V200 (available from UOP), or P200 (available from Sasol). Commercially available zeolite catalysts that may be suitable include CBV 8014, CBV 28014 (each available from Zeolyst). Commercially available amorphous aluminosilicate catalysts that may be suitable include silica-alumina catalyst support, grade 135 (available from Sigma-Aldrich). However, it should be understood that other suitable catalysts may be utilized to carry out the dehydration reaction.

[0048] According to one or more embodiments, the reaction can be a methanol to olefins reaction. According to such embodiments, the hydrocarbon feed stream can include methanol. According to one or more embodiments, the hydrocarbon feed stream can 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% methanol.

[0049] In one or more embodiments, the methanol-to-olefins reaction may utilize one or more zeolites as a catalyst. In such embodiments, the particulate solid may comprise one or more zeolites. In some embodiments, the one or more zeolites utilized in the methanol-to-olefins reaction may comprise one or more of ZSM-5 zeolite or SAPO-34 zeolite. However, it should be understood that other suitable catalysts may be utilized to carry out the methanol-to-olefins reaction.

[0050] In one or more embodiments, operating a chemical process can include passing a product stream out of a reactor. The product stream can include light olefins or alkylaromatic olefins such as styrene. As described herein, "light olefins" refers to one or more of ethylene, propylene, or butene. As described herein, many butenes include any isomer of butene, such as α-butylene, cis-β-butylene, trans-β-butylene, and isobutylene. In one embodiment, the product stream can include at least 30% by weight of light olefins. For example, the product stream can include at least 30% by weight of light olefins, at least 40% by weight of light olefins, at least 50% by weight of light olefins, at least 60% by weight of light olefins, at least 70% by weight of light olefins, at least 80% by weight of light olefins, at least 90% by weight of light olefins, at least 95% by weight of light olefins, or even at least 99% by weight of light olefins.

[0051] It should be noted that one or more of the following claims utilize the term "wherein" as a transitional phrase. For purposes of defining the art, it should be noted that 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."

[0052] It should be understood that when a first component is described as "comprising" a second component, in some embodiments it is contemplated that the first component "consists of" or "consists essentially of" that second component. It should further be understood that when a first component is described as "comprising" a second component, in some embodiments it is contemplated that the first component comprises at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or even at least 99% of that second component (where % can be by weight or mole %).

[0053] According to a first aspect of the present disclosure, a method for forming light olefins in a reactor system including a reactor and a regenerator includes: reacting a feed stream in the reactor in the presence of particulate solids to form a product stream, wherein the reaction forms coke on the particulate solids, the reaction being an endothermic reaction; transferring the particulate solids to a regenerator and burning at least a portion of the coke to heat the particulate solids; mixing air and an auxiliary fuel upstream of the regenerator to form a gas mixture, and transferring the gas mixture to the regenerator through a distributor; burning the auxiliary fuel in the regenerator to heat the particulate solids; and transferring the heated particulate solids from the regenerator to the reactor. The concentration of the auxiliary fuel in the gas mixture is less than 80% of the lower explosion limit of the auxiliary fuel in the gas mixture. The heat generated by burning at least a portion of the coke and the auxiliary fuel is sufficient to maintain the thermal balance of the reactor system.

[0054] A second aspect of the present disclosure may include the first aspect, wherein the supplemental fuel includes hydrogen, methane, ethane, propane, or natural gas.

[0055] A third aspect of the present disclosure may include either the first or second aspect, wherein the concentration of the auxiliary fuel in the gas mixture is between 25% of the lower explosive limit and 70% of the lower explosive limit.

[0056] A fourth aspect of the present disclosure may include any of the first to third aspects, wherein mixing the air and the supplemental fuel includes passing the air and the supplemental fuel through a static mixer.

[0057] A fifth aspect of the present disclosure may include any of the first to fourth aspects, wherein mixing the air and the auxiliary fuel includes injecting the auxiliary fuel into the air through a fuel gas distributor.

[0058] A sixth aspect of the present disclosure may include any of the first to fifth aspects, wherein the mixing of the air and the auxiliary fuel occurs at a temperature between ambient temperature and 400°C.

[0059] A seventh aspect of the present disclosure may include any of the first to sixth aspects, further including heating the gas mixture before moving the gas mixture through the distributor to the regenerator.

[0060] An eighth aspect of the present disclosure may include any of the first to seventh aspects, wherein the reaction of the feed stream includes a dehydrogenation reaction and a hydrogen combustion reaction.

[0061] A ninth aspect of the present disclosure may include any of the first to seventh aspects, wherein the reaction of the feed stream includes a cracking reaction.

[0062] A tenth aspect of the present disclosure may include any of the first to seventh aspects, wherein the reaction of the feed stream includes a dehydration reaction.

[0063] An eleventh aspect of the present disclosure may include any of the first to seventh aspects, wherein the reaction of the feed stream comprises a methanol-to-olefins reaction.

[0064] A twelfth aspect of the present disclosure may include any of the first through eleventh aspects, wherein the product stream includes one or more of ethylene, propylene, or butenes.

[0065] A thirteenth aspect of the present disclosure may include any one of the first to twelfth aspects, wherein the product stream comprises at least 30 wt% light olefins.

[0066] Additionally, the term "consisting essentially of" is used in this disclosure to refer to quantitative values ​​that do not materially affect the basic and novel characteristics of the disclosure. For example, a chemical composition "consisting essentially of" a particular chemical component or group of chemical components should be understood to mean that the composition contains at least about 99.5% of that particular chemical component or group of chemical components.

[0067] The subject matter of the present disclosure has been described in detail with reference to specific embodiments. It should be understood that any detailed description of an element or feature of an embodiment does not necessarily mean that the element or feature is essential to the particular embodiment or any other embodiment. Furthermore, it will be apparent to those skilled in the art that various modifications and variations can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter.

Claims

1. 1. A process for forming light olefins in a reactor system comprising a reactor and a regenerator, comprising: reacting the feed stream in the presence of particulate solids in said reactor to form a product stream, said reaction forming coke on said particulate solids, said reaction being endothermic; transferring the particulate solids to the regenerator and combusting at least a portion of the coke to heat the particulate solids; mixing air and auxiliary fuel upstream of the regenerator to form a gas mixture, and transferring the gas mixture through a distributor to the regenerator; burning the supplemental fuel in the regenerator to heat the particulate solids; transferring the heated particulate solids from the regenerator to the reactor; the concentration of the auxiliary fuel in the gas mixture is less than 80% of the lower explosion limit of the auxiliary fuel in the gas mixture; The method wherein the heat generated by burning at least a portion of the coke and the supplemental fuel is sufficient to maintain heat balance in the reactor system.

2. The method of claim 1 , wherein the supplemental fuel comprises hydrogen, methane, ethane, propane, or natural gas.

3. 3. The method according to claim 1, wherein the concentration of the auxiliary fuel in the gas mixture is from 25% of the lower explosion limit to 70% of the lower explosion limit.

4. The method of any one of claims 1 to 3, wherein mixing the air and the supplemental fuel comprises passing the air and the supplemental fuel through a static mixer.

5. The method of any one of claims 1 to 4, wherein mixing the air and the supplemental fuel comprises injecting the supplemental fuel into the air through a fuel gas distributor.

6. The method according to any one of claims 1 to 5, wherein the mixing of the air and the auxiliary fuel is carried out at a temperature between ambient temperature and 400°C.

7. The method of any of claims 1 to 6, further comprising heating the gas mixture before transferring the gas mixture through the distributor to the regenerator.

8. The method of any of claims 1 to 7, wherein the reactions of the feed stream include dehydrogenation and hydrogen combustion reactions.

9. The method of any of claims 1 to 7, wherein the reaction of the feed stream comprises a cracking reaction.

10. The method of any of claims 1 to 7, wherein the reaction of the feed stream comprises a dehydration reaction.

11. The process of any of claims 1 to 7, wherein the reaction of the feed stream comprises a methanol to olefins reaction.

12. The method of any preceding claim, wherein the product stream comprises one or more of ethylene, propylene, or butenes.

13. The process of any preceding claim, wherein the product stream comprises at least 30 wt% light olefins.

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