Process for preparing light olefins

Abstract

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

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 428,494, filed on November 29, 2022, the entire disclosure of which is hereby incorporated by reference herein. Technical field

[0003] The various embodiments described herein generally relate to chemical processing, and more particularly, to methods and systems for catalyzing chemical conversions. Background art

[0004] Many chemicals can be produced by processes that employ particulate solids such as solid particulate catalysts. In these processes, the particulate solids can become "spent" and have reduced activity in subsequent reactions. Additionally, endothermic processes require heat, and the "spent" catalyst must be reheated. Thus, the spent particulate solids can be transferred to a regeneration unit for reheating and regeneration to increase the activity of the particulate solids for use in subsequent reactions. After regeneration in the regeneration unit, the regenerated particulate solids can be transferred back to the reactor for use in subsequent reactions. Summary of the invention

[0005] There is a need for improved methods for regenerating particulate solids for light olefin production. Methods for regenerating particulate solids can include burning a supplementary fuel to heat the catalyst. The supplementary fuel and air can be introduced into a combustion chamber through separate distributors. Coke can form on the metal surface of the distributor used to inject the supplementary fuel into the combustion chamber. The formation of coke on the distributor can clog the distributor and force the shutdown of the catalyst regeneration system. Additionally, due to the fact that the combustion chamber vessel can be large and operate at extremely high temperatures, mechanical limitations in arranging fuel gas distributors across the entire cross - section of the vessel can limit the size of the vessel that can be built.

[0006] One or more of the disclosed methods for forming light olefins according to the present invention can address this problem. In one or more embodiments, air and supplementary fuel can be mixed upstream of the combustion chamber. This gas mixture can be injected into the combustion chamber through a single distributor, which can reduce the formation of coke on the distributor and may enable vessels operating in the temperature range of 750 °C to 915 °C to not require multiple distributors to be arranged across the entire cross - section of the vessel. The concentration of the supplementary fuel and air in the gas mixture can be controlled such that the percentage of the supplementary fuel in the gas mixture is below the lower explosive limit of the supplementary fuel. This can reduce the risk of the gas mixture burning before being injected into the combustion chamber.

[0007] 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 reactor in the presence of particulate solids to form a product stream. The reaction may form coke on the particulate solids, and the reaction may be an endothermic reaction. The method may include transporting the particulate solids to the regenerator and burning at least a portion of the coke to heat the particulate solids. The method may include mixing air and supplemental fuel upstream of the regenerator to form a gas mixture and transporting the gas mixture to the regenerator through a distributor. The method may include burning the supplemental fuel in the regenerator to heat the particulate solids and transporting the heated particulate solids from the regenerator to the reactor. The concentration of the supplemental fuel in the gas mixture may be less than 80% of the lower explosive limit of the supplemental fuel in the gas mixture, and the heat generated by burning at least a portion of the coke and the supplemental fuel may be sufficient to maintain the heat balance of the reactor system. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The following detailed description of specific embodiments of the present disclosure may be best understood when read in conjunction with the following drawings, in which like reference numerals indicate like structures and in which:

[0009] Figure 1 A reactor system including a reactor section and a regenerator section is schematically depicted in accordance with one or more embodiments disclosed herein; and

[0010] Figure 2 A cross-sectional view of a plate grid distributor is schematically depicted in accordance with one or more embodiments disclosed herein.

[0011] It should be understood that the drawings are schematic in nature and do not include some components commonly used in a fluid catalytic reactor system in the art, such as but not limited to temperature transmitters, pressure transmitters, flow meters, pumps, valves, etc. It is well known that these components are within the substance and scope of the disclosed embodiments herein. However, operating components (such as those described in the present disclosure) may be added to the embodiments described in the present disclosure.

[0012] Reference will now be made in more detail to various embodiments, some of which are shown in the drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or like components. DETAILED DESCRIPTION

[0013] As described herein, a method for preparing light olefins may include reacting a feed stream in the presence of a particulate solid to form a product stream. The reaction may form coke on the particulate solid, and the particulate solid may be regenerated by burning the coke to heat the particulate solid. The method may also include mixing a supplemental fuel with air to form a gas mixture, delivering the gas mixture to a regenerator, and then burning the supplemental fuel in the regenerator to heat the particulate solid. The heated particulate solid may be delivered back to the reactor. Such methods may utilize a system having specific characteristics, such as a specific orientation of system components. A specific embodiment disclosed in detail herein is depicted in Figure 1 . However, it should be understood that the principles disclosed and taught herein may be applicable to other systems that utilize different system components oriented in different ways, or different reaction schemes that utilize various catalyst compositions.

[0014] In a non-limiting example, the reactor system 102 described herein may be used to produce light olefins from a hydrocarbon feed stream. Light olefins may be produced from various hydrocarbon feed streams by utilizing different reaction mechanisms. For example, light olefins may be produced by at least dehydrogenation reactions, cracking reactions, dehydration reactions, and methanol-to-olefins reactions. These reaction types may utilize different feed streams and different particulate solids to produce light olefins. It should be understood that when "particulate solid" is referred to herein, it may equivalently refer to the catalyst mentioned with respect to the Figure 1 system.

[0015] Now referring to Figure 1 , an example reactor system 102 that may be suitable for use with the methods described herein is schematically depicted. However, it should be understood that other reactor system configurations may be applicable to the methods described herein. The reactor system 102 generally includes a plurality of system components, such as a reactor section 200 and / or a catalyst handling section 300. As used herein in the context of Figure 1 , the reactor section 200 generally refers to the part of the reactor system 102 where the main 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 Figure 1As depicted, the reactor section 200 may additionally include a catalyst separation section 210 for separating the catalyst from the chemical products formed in the reactor 202. Additionally, as used herein, the catalyst treatment section 300 generally refers to the portion of the reactor system 102 that treats the catalyst in some manner (such as by combustion). The catalyst treatment section 300 may include a combustion chamber 350 and a riser 330, and may optionally include a catalyst separation section 310. In some embodiments, the catalyst may be regenerated by burning off contaminants such as coke in the catalyst treatment section 300. In an embodiment, the catalyst may be heated in the catalyst treatment section 300. If no coke or other combustible material is formed on the catalyst, or the amount of coke formed on the catalyst is insufficient to burn to heat the catalyst to the desired temperature, supplemental fuel may be used to heat the catalyst in the catalyst treatment section 300. In one or more embodiments, the catalyst separation section 210 may be in fluid communication with the burner 350 (e.g., via a standpipe 426), and the catalyst separation section 310 may be in fluid communication with the upstream reactor section 250 (e.g., via a standpipe 424 and a transport riser 430).

[0016] As regarding Figure 1As described, a feed stream can enter the transport riser 430, and a product stream can leave the reactor system 102 via line 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 upward and through the downstream reactor section 230 to produce a chemical product. The chemical product and the 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 transported out of the catalyst separation section 210. The separated catalyst is transferred from the catalyst separation section 210 to a combustor 350. In the combustor 350, the catalyst can be treated, e.g., by burning. 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 transferred out of the combustor 350 and through a riser 330 to a 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 transported to a 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 spent catalyst or make-up fuel). The separated catalyst is then transferred from the catalyst separation section 310 to the upstream reactor section 250 via a standpipe 424 and a transport riser 430, where the catalyst is further used for the catalytic reaction. Thus, the catalyst can be recycled between the reactor portion 200 and the catalyst treatment portion 300 during operation. Generally, the treated chemical stream, including the feed stream and the product stream, can be gaseous, and the catalyst can be a fluidized particulate solid.

[0017] In addition, as described herein, the structural features of the reactor section 200 and the regeneration section 300 may be similar or identical in some aspects. For example, each of the reactor section 200 and the regeneration section 300 includes a reaction vessel (i.e., the upstream reactor section 250 of the reactor section 200, and the combustion chamber 350 of the regeneration section 300), a riser (i.e., the riser 230 of the reactor section 200 and the riser 330 of the regeneration section 300), and a granular solid separation section (i.e., the granular solid separation section 210 of the reactor section 200 and the granular solid separation section 310 of the regeneration section 300). It should be understood that because many of the structural features of the reactor section 200 and the regeneration section 300 may be similar or identical in some respects, similar or identical portions of the reactor section 200 and the regeneration section 300 have been provided with reference numerals having the same last two digits throughout the present disclosure, and disclosure relating to one portion of the reactor section 200 may apply to similar or identical portions of the regeneration section 300, and vice versa.

[0018] According to one or more embodiments described herein, the reactor portion 200 can include 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 with the downstream reactor section 230. According to one or more embodiments, the upstream reactor section 250 and the downstream reactor section 230 can each have a substantially constant cross-sectional area, while the transition section 258 can be tapered and not have a constant cross-sectional area. As described herein, unless otherwise expressly stated, "cross-sectional area" refers to the area of ​​a cross-section of a portion of a reactor part in a plane substantially orthogonal to the overall flow direction of reactants and / or products. For example, in Figure 1 In the figure, the cross-sectional area direction of the upstream reactor section 250, the transition section 258 and the downstream reactor section 230 is from the horizontal direction to the vertical direction of the page (orthogonal to the direction of fluid movement, i.e. Figure 1 The plane direction defined by the vertical upward direction in .

[0019] like Figure 1 As 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.

[0020] As described herein, the upstream reactor section 250 can include a vessel, a drum, a barrel, a tank, or other vessel suitable for a given chemical reaction. In one or more embodiments, the upstream reactor section 250 can generally be cylindrical in shape (i.e., having a generally circular cross-sectional shape), or alternatively can be a non-cylindrical shape, such as a prismatic shape, the cross-sectional shape of which is triangular, rectangular, pentagonal, hexagonal, octagonal, oval, or other polygon, or a curved closed shape, or a combination thereof. As used throughout this disclosure, the upstream reactor section 250 can generally include a metal frame and can additionally include a refractory lining or other materials for protecting the metal frame and / or controlling processing conditions. As Figure 1 depicted, the upstream reactor section 250 can include a lower reactor portion catalyst inlet port 252 that defines the connection of the transport riser 430 to the upstream reactor section 250.

[0021] It should be understood that any two quantitative values assigned to a property can constitute a range of that property, and all combinations of ranges formed by all such quantitative values of a given property are contemplated in this disclosure. It should be understood that in some embodiments, the compositional ranges of chemical components in a composition should be understood to contain mixtures of isomers of that component. In additional embodiments, chemical compounds can exist in alternative forms, such as derivatives, salts, hydroxides, etc. Generally, the "inlet port" and "exit port" of any system unit of the reactor system 102 described herein refer to openings, holes, channels, apertures, gaps, or other similar mechanical features in the system unit. For example, the inlet port allows material to enter a particular system unit and the exit port allows material to leave a particular system unit. Generally, the exit port or inlet port will define a region of the system unit of the reactor system 102 to which a pipe, conduit, tube, hose, transport line, or similar mechanical feature is attached, or defines a portion of the system to which another system unit is directly attached. Although the inlet port and exit port can sometimes be described herein as operating functionally, they can have similar or identical physical characteristics, and their corresponding functions in the operable system should not be construed as limiting their physical structure.

[0022] The upstream reactor section 250 can be connected to a transfer riser 430, which in operation can supply processed catalyst and / or reactant chemicals in a feed stream to the reactor section 200. The processed 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 transfer riser 430 can be passed through a standpipe 424 to the transfer riser 430 and thus arrives from the catalyst processing section 300. In some embodiments, the catalyst can come directly from the catalyst separation section 210 via the standpipe 422 and enter the transfer riser 430, where the catalyst enters the upstream reactor section 250. The catalyst can also be fed directly into the upstream reactor section 250 via 422. This catalyst can be slightly deactivated, but in some embodiments can still be suitable for reaction in the upstream reactor section 250. As used herein, "deactivated" can refer to a catalyst contaminated with a substance such as coke or having a temperature lower than desired. Regeneration can remove contaminants (such as coke), raise the catalyst temperature, or both.

[0023] Still referring to Figure 1 , the reactor section 200 can include a downstream reactor section 230 for transporting reactants, products, and / or catalyst from the upstream reactor section 250 to the catalyst separation section 210. In one or more embodiments, the downstream reactor section 230 can generally be cylindrical in shape (i.e., having a generally circular cross-sectional shape), or alternatively can be non-cylindrical in shape, such as a prismatic shape, the cross-sectional shape of which is triangular, rectangular, pentagonal, hexagonal, octagonal, elliptical, or other polygon, or a curved closed shape, or a combination thereof. As used throughout this disclosure, the downstream reactor section 230 can generally include a metal frame and can additionally include a refractory lining or other materials for protecting the metal frame and / or controlling processing conditions.

[0024] 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, an "external riser section" refers to the portion of the riser located outside the catalyst separation section, and an "internal riser section" refers to the portion of the riser located inside the catalyst separation section. For example, in Figure 1 the depicted embodiment, the internal riser section 234 of the reactor section 200 can be positioned within the catalyst separation section 210, while the external riser section 232 is positioned outside the catalyst separation section 210.

[0025] As Figure 1As 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.

[0026] In some embodiments, such as those in which the upstream reactor section 250 and the downstream reactor section 230 have similar cross-sectional shapes, the transition section 258 can be shaped as a frustum. For example, for an embodiment of the reactor portion 200 that includes a cylindrical upstream reactor section 250 and a cylindrical downstream reactor section 230, the transition section 258 can be shaped as a conical frustum. However, it should be understood that a wide variety of upstream reactor section 250 shapes are contemplated herein that connect upstream reactor sections 250 and downstream reactor sections 230 of various shapes and sizes.

[0027] In operation, the catalyst can move upward through the downstream reactor section 230 (from the upstream reactor section 250) and then enter the separation device 220. The separated vapor can be removed from the reactor system 102 via a conduit 420 at the gas outlet port 216 of the catalyst separation section 210. According to one or more embodiments, the separation device 220 can be a cyclone separation system, which can 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 can enter a secondary cyclone separation device for further separation. The primary cyclone separation device can 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, such as secondary and tertiary cyclone separators, are used to further separate the catalyst from the product gas. It should be understood that any primary cyclone separation device can be used in the embodiments of the present invention.

[0028] According to one or more embodiments, after the catalyst is separated from the vapor in the separation device 220, the catalyst can typically move through the stripper 224 to the catalyst outlet port 222, where the catalyst is transferred out of the reactor section 200 via the riser 426 and into the catalyst processing section 300. Optionally, the catalyst can also be transferred directly back to the upstream reactor section 250 through the riser 422. Alternatively, the catalyst can be premixed with the treated catalyst in the transport riser 430.

[0029] As detailed according to Figure 1 the embodiments, according to one or more embodiments, the catalyst can be treated by one or more of the following steps: transporting the catalyst from the reactor 202 to the combustion chamber 350, burning a supplemental fuel source in the combustion chamber 350 to heat the catalyst, and transporting the heated catalyst from the combustion chamber 350 to the reactor 202.

[0030] Now referring to the catalyst processing section 300, as Figure 1 depicted, the burner 350 of the catalyst processing section 300 can include one or more lower reactor section inlet ports 352 and can be in fluid communication with the riser 330. The burner 350 can be in fluid communication with the catalyst separation section 210 via the riser 426, which can supply spent catalyst from the reactor section 200 to the catalyst processing section 300 for regeneration.

[0031] In one or more embodiments, a gas mixture comprising air and supplemental fuel can be transported to the combustion chamber 350 through the lower reactor inlet port 352. The gas mixture can be formed by mixing air and supplemental fuel upstream of the combustion chamber 350. In an embodiment, air and supplemental fuel can be mixed in a static mixer 450. The static mixer 450 can be any static mixer suitable for mixing gases. For example, the static mixer can include a housing and one or more flow deflectors positioned within the housing. In an embodiment, one or more of the flow deflectors can be helical. In an embodiment, the static mixer can be a plate-type static mixer. Without being limited to a particular theory of explanation, it is believed that the structure of the static mixer creates turbulence, thereby mixing the fluid flowing through the static mixer. The gas mixture can be transported from the static mixer 450 to the combustion chamber 350 through a conduit 428. In an embodiment, air can be transported to the static mixer 450 through a conduit 452, and supplemental fuel can be transported to the static mixer 450 through a conduit 454. In one or more embodiments, the supplemental fuel can include hydrogen, methane, natural gas, ethane, propane, or any gas that generates heat upon combustion. In one or more embodiments, the air can be oxygen-rich. For example, oxygen-rich air can contain greater than 21 mole % oxygen, or 21 mole % to 40 mole % oxygen.

[0032] In one or more embodiments, the fuel gas dispenser may inject supplementary fuel into the air upstream of the static mixer within conduit 452. Without being limited to a particular theory of explanation, this may enable a more uniform distribution of the supplementary fuel in the air when the air and supplementary fuel are delivered to the static mixer 450. Now referring to Figure 2 , the fuel gas dispenser may be a plate grid dispenser 900. In an embodiment, the plate grid dispenser 900 may include a plate 910 and a refractory lining 920 disposed on the downstream side of the plate 910. The plate grid dispenser 900 may include a plurality of injection points ( Figure 2 the depicted injection points 930 and 940). In Figure 2 the depicted embodiment, the injection point 930 is configured to allow both air and supplementary fuel to pass through the injection point 930. The supplementary fuel may pass through tube 932, and the air may pass through the annular space between tube 934 and tube 932 and between the plate 910 and tube 932. It should be understood that tube 932 may be connected to a supplementary fuel source (not shown). In Figure 2 the depicted embodiment, the injection point 940 is configured to allow air to pass through the injection point 940.

[0033] In some embodiments, the fuel gas and air may be delivered through each injection point of the dispenser. In some embodiments, the fuel gas and air may be delivered through separate injection points. In one or more embodiments, each fuel gas injection point may be provided with a corresponding air injection point. For example, each fuel gas injection point may be provided with more than one corresponding air injection point. For example, each fuel gas injection point may be provided with 2 to 10 corresponding air injection points. Without being limited to a particular theory of explanation, delivering the fuel gas and air through each injection point may achieve good fuel gas distribution, but may result in a relatively complex system design and maintenance. Similarly, a dispenser including one fuel gas injection point corresponding to each air injection point may provide good fuel gas distribution, but may result in a relatively complex system design and maintenance. On the other hand, including a plurality of air injection points corresponding to each fuel gas injection point may reduce the complexity of the fuel gas dispenser while maintaining a satisfactory fuel gas distribution.

[0034] Without being limited to a particular theory of explanation, again referring to Figure 1, mixing air and supplemental fuel upstream of the combustion chamber 350 can produce a more uniform mixture of supplemental fuel and air in the combustion chamber 350 compared to what occurs by introducing the supplemental fuel and air separately into the combustion chamber. A homogeneous mixture of air and supplemental fuel can ensure that once the fuel enters the combustion chamber 350, the oxygen-to-fuel stoichiometric ratio in local regions is sufficient to support fuel combustion. The homogeneous mixture of air and supplemental fuel can promote uniform combustion of the fuel within the combustion chamber 350, thereby reducing the formation of hot spots within the combustion chamber 350. Additionally, if the air and supplemental fuel are not uniformly mixed, there may be local regions that exceed the lower explosive limit of the fuel.

[0035] In an embodiment, the gas mixture can be introduced into the combustion chamber 350 through a single dispenser. The dispenser can include a plurality of nozzles that are operable to uniformly distribute the gas mixture within the combustion chamber 350. A suitable fuel gas dispenser is described in U.S. Patent No. 9,889,418, the entire content of which is incorporated herein by reference. Without being limited to a particular theoretical explanation, introducing the gas mixture through a single dispenser can reduce the likelihood of coke accumulation on the dispenser. When the supplemental fuel and air are each introduced into the combustion chamber 350 through their own dispensers separately, coke may form on the fuel gas dispenser under the high-temperature conditions of the combustion chamber 350. This coke accumulation can clog the dispenser, which may prevent the supplemental fuel from being uniformly introduced into the combustion chamber 350 and may even cause a forced shutdown of the reactor system 102. Without being limited to a particular theoretical explanation, when a plate grid dispenser is used, a heat-insulating refractory layer can be installed on top of the dispenser to control the mixture of air and supplemental fuel to a desired temperature. The refractory layer can provide heat-insulating protection to the bottom of the dispenser, keeping the temperature at the bottom of the dispenser consistent with the temperature of the gas flowing through the dispenser. The pipe leading to the dispenser may be at least partially covered with a thin, high-density refractory material, the heat-insulating effect of which may be inferior to the refractory layer installed on top of the dispenser.

[0036] In one or more embodiments, when well mixed, the volume concentration of the supplemental fuel in the gas mixture may be below the lower explosive limit of the supplemental fuel. As used herein, the "lower explosive limit" (LEL) of a gas is the lowest volume concentration of the gas in air that can be ignited by an ignition source such as an electric arc, flame, or heat. For example, the concentration of the supplemental fuel in the gas mixture can be less than or equal to 90% of the LEL of the supplemental fuel, less than or equal to 85% of the LEL of the supplemental fuel, less than or equal to 80% of the LEL of the supplemental fuel, less than or equal to 75% of the LEL of the supplemental fuel, less than or equal to 70% of the LEL of the supplemental fuel, less than or equal to 65% of the LEL of the supplemental fuel, less than or equal to 60% of the LEL of the supplemental fuel, less than or equal to 50% of the LEL of the supplemental fuel, less than or equal to 45% of the LEL of the supplemental fuel, less than or equal to 40% of the LEL of the supplemental fuel. In one or more embodiments, the concentration of the supplemental fuel in the gas mixture can be from 25% to 90% of the LEL. For example, the concentration of the supplemental fuel in the gas mixture can be from 25% to 90%, from 30% to 90%, from 35% to 90%, from 40% to 90%, from 45% to 90%, from 50% to 90%, from 55% to 90%, from 60% to 90%, from 65% to 90%, from 70% to 90%, from 75% to 90%, from 80% to 90%, from 85% to 90%, from 25% to 85%, from 25% to 80%, from 25% to 75%, from 25% to 70%, from 25% to 65%, from 25% to 60%, from 25% to 55%, from 25% to 50%, from 25% to 45%, from 25% to 40%, from 25% to 35%, from 25% to 30%, or any combination or subset of these ranges.

[0037] Generally speaking, the LEL of a gas can change with temperature, pressure, and oxygen concentration. For example, when the temperature increases, the LEL decreases; when the pressure increases, the LEL decreases; when the oxygen concentration increases, the LEL also decreases. In one or more embodiments, air and supplemental fuel can be mixed under ambient conditions, and the LEL of the gas mixture can be determined based on ambient conditions such as atmospheric pressure and a temperature of about 25°C. In an embodiment, the gas mixture can be injected into the combustion chamber at approximately ambient temperature. In one or more embodiments, air and supplemental fuel can be mixed at a temperature and pressure that is higher than ambient temperature, higher than ambient pressure, or both higher than ambient temperature and higher than ambient pressure. For example, air and supplemental fuel can be mixed at a temperature from ambient temperature to 400°C, from ambient temperature to 300°C, from ambient temperature to 200°C, or from ambient temperature to 100°C. In such embodiments, the LEL under the mixing conditions can be predicted mathematically. The LEL can be predicted and controlled by a control system including sensors such as temperature sensors, pressure sensors, and analyzers that can measure the concentration of fuel gas or oxygen. The control system can be capable of automatically adjusting the flow rates of air and fuel gas to prevent the concentration of the air and fuel gas mixture from exceeding the LEL threshold.

[0038] In one or more embodiments, the gas mixture can be heated between the static mixer 450 and the combustion chamber 350. For example, the gas mixture can be heated before being delivered to the regenerator through the distributor. In such embodiments, at ambient conditions, the concentration of the supplemental fuel in the gas mixture can be sufficiently below the LEL to ensure that after the gas mixture is heated, the concentration of the supplemental fuel therein can remain below the LEL. In one or more embodiments, the gas mixture can be heated to a temperature of up to 800 °C (including this temperature). For example, the gas mixture can be heated to a temperature of up to 800 °C, 700 °C, 600 °C, 500 °C, or 400 °C (including these temperatures). In an embodiment, the gas mixture can be heated to the following temperatures: 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 an embodiment, the gas mixture can be heated to a temperature such that the concentration of the supplemental fuel is less than or equal to 80% of the LEL. For example, the gas mixture can be heated to a temperature such that the concentration of the supplemental fuel is less than or equal to 80% of the LEL, 75% of the LEL, 70% of the LEL, 65% of the LEL, or 60% of the LEL. In an embodiment, the gas mixture can be heated to a temperature that is lower than or equal to the autoignition temperature of the supplemental fuel. Without being limited to a particular theory of explanation, when the gas mixture is preheated, both the amount of the supplemental fuel required and the amount of oxygen necessary for its combustion can be reduced. This can allow for the use of smaller process equipment.

[0039] Without being limited to a particular theory of explanation, when the concentration of the supplemental fuel in the gas mixture remains below the LEL of the supplemental fuel, the risk of the gas mixture being ignited before being introduced into the combustion chamber 350 is significantly reduced. Additionally, the explosion risk of the gas mixture is reduced. Reducing the risk of explosion or combustion of the gas mixture outside the combustion chamber 350 is crucial because such an accident can pose safety hazards, damage system components, or cause the reactor system 102 to shut down forcibly.

[0040] In one or more embodiments, burning coke and the supplemental fuel in the combustion chamber 350 can heat the catalyst. Subsequently, the heated catalyst can be delivered to the reactor 250 and provide heat to the reactor. In one or more embodiments, the heat generated by burning coke and the supplemental fuel may be sufficient to maintain the thermal balance of the reactor. In one or more embodiments, burning coke and the supplemental fuel in the combustion chamber 350 can be the sole means for heating the catalyst.

[0041] In an embodiment, light olefins can be produced by one or more endothermic reactions. As used herein, an "endothermic reaction" is a chemical process in which the enthalpy or internal energy of a system increases such that the system absorbs thermal energy from its surroundings. Without being limited to a particular theoretical explanation, when an endothermic reaction occurs in reactor 250, thermal energy can be absorbed from the catalyst entering reactor 250 such that the temperature of the catalyst exiting reactor 250 can be lower than the temperature of the catalyst when it enters reactor 250. Thus, the catalyst can be heated in combustion chamber 350 such that the catalyst can provide sufficient heat to drive the endothermic reaction to occur in reactor 250 and maintain the thermal balance of system 102.

[0042] In one or more embodiments, additional supplemental fuel may be required to heat the catalyst. In such embodiments, reactor 350 can include a second dispenser for injecting the supplemental fuel into the combustion chamber. The second dispenser can be any suitable device for injecting the supplemental fuel into the reactor.

[0043] 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 using 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 the following endothermic reactions: including but not limited to dehydrogenation reactions, cracking reactions, dehydration reactions, and methanol-to-olefin reactions. These reaction types can use different feed streams and different particulate solids to produce light olefins. It should be understood that when "catalyst" is referred to herein, these catalysts can also refer to the particulate solids mentioned with respect to Figure 1 the system.

[0044] 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.

[0045] 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.

[0046] 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. The oxygen carrier material can include one or more transition metal oxides. According to one or more embodiments, one or more transition metal oxides can be redox-active transition metal oxides. Redox-active transition metal oxides include binary, ternary, or other mixed metal oxides capable of undergoing reduction reactions in the presence of a reducing agent (such as hydrogen) and oxidation reactions in the presence of an oxidizing agent (such as oxygen or air). In some embodiments, the redox-active transition metal oxides can 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 can be a solid. In a specific embodiment, the oxygen carrier material can be a crushed solid or powder. Examples of such reaction mechanisms are disclosed in WO 2020 / 046978 and WO 2019 / 048391, which are considered possible reaction mechanisms for the systems and methods described herein, and the teachings of both patents are incorporated herein by reference in their entireties.

[0047] According to one or more embodiments, the reaction can be a cracking reaction. According to such embodiments, the hydrocarbon feed stream can contain one or more of naphtha, n-butane, or isobutane. According to one or more embodiments, the hydrocarbon feed stream can contain at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% of naphtha. In additional embodiments, the hydrocarbon feed stream can contain at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% of n-butane. In additional embodiments, the hydrocarbon feed stream can contain at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% of isobutane. In additional embodiments, the hydrocarbon feed stream can contain at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% of the sum of naphtha, n-butane, and isobutane.

[0048] In one or more embodiments, the cracking reaction can utilize one or more zeolites as catalysts. In such embodiments, the particulate solid can include one or more zeolites. In some embodiments, the one or more zeolites utilized in the cracking reaction can include ZSM-5 zeolite. However, it should be understood that other suitable catalysts can be utilized for the cracking reaction. For example, suitable commercially available catalysts can include Intercat Super Z Excel or Intercat Super Z Exceed. In additional embodiments, in addition to the catalytically active material, the cracking catalyst can further include platinum. For example, the cracking catalyst can contain from 0.001 wt% to 0.05 wt% of platinum. The platinum can be sprayed in the form of platinum nitrate and calcined at an elevated temperature (such as about 700 °C). Without being bound by theory, it is believed that adding platinum to the catalyst can allow for easier combustion of supplementary fuels such as methane.

[0049] According to one or more embodiments, the reaction can be a dehydration reaction. According to such embodiments, the hydrocarbon feed stream can contain one or more of ethanol, propanol, or butanol. According to one or more embodiments, the hydrocarbon feed stream can contain at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% of ethanol. In additional embodiments, the hydrocarbon feed stream can contain at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% of propanol. In additional embodiments, the hydrocarbon feed stream can contain at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% of butanol. In additional embodiments, the hydrocarbon feed stream can contain at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% of the sum of ethanol, propanol, and butanol.

[0050] In one or more embodiments, the dehydration reaction can utilize one or more acid catalysts. In such embodiments, the particulate solid can include one or more acid catalysts. In some embodiments, the one or more acid catalysts utilized in the dehydration reaction can include zeolites (such as ZSM-5 zeolite), alumina, amorphous aluminosilicate, acidic clay, or combinations thereof. For example, according to one or more embodiments, commercially available alumina catalysts that may be suitable include SynDol (obtainable from Scientific Design Company), V200 (obtainable from UOP), or P200 (obtainable from Sasol). Commercially available zeolite catalysts that may be suitable include CBV 8014, CBV 28014 (each obtainable from Zeolyst). Commercially available amorphous aluminosilicate catalysts that may be suitable include silica-alumina catalyst support, grade 135 (obtainable from Sigma Aldrich). However, it should be understood that other suitable catalysts can be utilized for the dehydration reaction.

[0051] According to one or more embodiments, the reaction can be a methanol-to-olefins reaction. According to such embodiments, the hydrocarbon feed stream can contain methanol. According to one or more embodiments, the hydrocarbon feed stream can contain at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt% or even at least 99 wt% of methanol.

[0052] In one or more embodiments, the methanol-to-olefins reaction can utilize one or more zeolites as catalysts. In such embodiments, the particulate solid can include one or more zeolites. In some embodiments, the one or more zeolites utilized in the methanol-to-olefins reaction can include one or more of ZSM-5 zeolite or SAPO-34 zeolite. However, it should be understood that other suitable catalysts can be utilized for the methanol-to-olefins reaction.

[0053] In one or more embodiments, the operation of a chemical process can include discharging a product stream from a reactor. The product stream can contain light olefins or alkyl aromatic olefins, such as styrene. As used herein, "light olefins" refers to one or more of ethylene, propylene, or butene. As used herein, butene can include any isomer of butene, such as α-butene, cis-β-butene, trans-β-butene, and isobutene. In one embodiment, the product stream can contain at least 30 wt% light olefins. For example, the product stream can contain at least 30 wt% light olefins, at least 40 wt% light olefins, at least 50 wt% light olefins, at least 60 wt% light olefins, at least 70 wt% light olefins, at least 80 wt% light olefins, at least 90 wt% light olefins, at least 95 wt% light olefins, or even at least 99 wt% light olefins.

[0054] It should be noted that one or more of the appended claims utilize the term "wherein" as a transitional phrase. For purposes of defining the technology, it should be noted that this term is introduced in the claims as an open-ended 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 common open-ended preamble term "comprising".

[0055] It should be understood that where a first component is described as "comprising" a second component, it is contemplated that in some embodiments, the first component "consists of" or "consists essentially of" the second component. It should also be understood that where a first component is described as "comprising" a second component, it is contemplated that in some embodiments, the first component can contain 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 the second component (where % can be wt% or mol%).

[0056] 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 and wherein the reaction is endothermic; conveying the particulate solids to the regenerator and burning at least a portion of the coke to heat the particulate solids; mixing air with a supplemental fuel upstream of the regenerator to form a gas mixture and conveying the gas mixture to the regenerator through a distributor; burning the supplemental fuel in the regenerator to heat the particulate solids; and conveying the heated particulate solids from the regenerator to the reactor. The concentration of the supplemental fuel in the gas mixture is less than 80% of the lower explosive limit of the supplemental fuel in the gas mixture. The heat generated by burning at least a portion of the coke and the supplemental fuel is sufficient to maintain the heat balance of the reactor system.

[0057] A second aspect of the present disclosure may include the first aspect, wherein the supplementary fuel includes hydrogen, methane, ethane, propane, or natural gas.

[0058] A third aspect of the present disclosure may include the first aspect or the second aspect, wherein the concentration of the supplementary fuel in the gas mixture is from 25% of the lower explosive limit to 70% of the lower explosive limit.

[0059] A fourth aspect of the present disclosure may include any one of the first aspect to the third aspect, wherein mixing the air with the supplementary fuel includes flowing the air and the supplementary fuel through a static mixer.

[0060] A fifth aspect of the present disclosure may include any one of the first aspect to the fourth aspect, wherein mixing the air with the supplementary fuel includes injecting the supplementary fuel into the air through a fuel gas distributor.

[0061] A sixth aspect of the present disclosure may include any one of the first aspect to the fifth aspect, wherein mixing the air with the supplementary fuel is carried out at a temperature from ambient temperature to 400 °C.

[0062] A seventh aspect of the present disclosure may include any one of the first aspect to the sixth aspect, wherein the method further includes heating the gas mixture before delivering the gas mixture to the regenerator through a distributor.

[0063] An eighth aspect of the present disclosure may include any one of the first aspect to the seventh aspect, wherein reacting the feed stream includes carrying out a dehydrogenation reaction and a hydrogen combustion reaction.

[0064] A ninth aspect of the present disclosure may include any one of the first aspect to the seventh aspect, wherein reacting the feed stream includes carrying out a cracking reaction.

[0065] A tenth aspect of the present disclosure may include any one of the first aspect to the seventh aspect, wherein reacting the feed stream includes carrying out a dehydration reaction.

[0066] An eleventh aspect of the present disclosure may include any one of the first aspect to the seventh aspect, wherein reacting the feed stream includes carrying out a methanol-to-olefins reaction.

[0067] A twelfth aspect of the present disclosure may include any one of the first aspect to the eleventh aspect, wherein the product stream contains one or more of ethylene, propylene, or butene.

[0068] A thirteenth aspect of the present disclosure may include any one of the first aspect to the twelfth aspect, wherein the product stream contains at least 30% by weight of light olefins.

[0069] 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 that "consists essentially of" a particular chemical component or group of chemical components is to be understood to mean that the composition contains at least about 99.5% of the particular chemical component or group of chemical components.

[0070] The subject matter of this disclosure has been described in detail and with reference to specific embodiments. It should be understood that any detailed description of components or features of an embodiment does not necessarily imply that such components or features are necessary for a particular embodiment or any other embodiment. Further, it will be apparent to those skilled in the art that various modifications and changes can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter.

Claims

1. A method for forming light olefins in a reactor system comprising a reactor and a regenerator, the method comprising: In the reactor, a feed stream is reacted in the presence of particulate solids to form a product stream, wherein the reaction forms coke on the particulate solids and wherein the reaction is endothermic; The particulate solids are conveyed to the regenerator and at least a portion of the coke is burned to heat the particulate solids; Air and supplementary fuel are mixed upstream of the regenerator to form a gas mixture, and the gas mixture is conveyed to the regenerator through a distributor; The supplementary fuel is burned in the regenerator to heat the particulate solids; and The heated particulate solids are conveyed from the regenerator to the reactor, wherein: The concentration of the supplementary fuel in the gas mixture is less than 80% of the lower explosive limit of the supplementary fuel in the gas mixture; and The heat generated by burning at least a portion of the coke and the supplementary fuel is sufficient to maintain the heat balance of the reactor system.

2. The method according to claim 1, wherein the supplementary fuel comprises hydrogen, methane, ethane, propane or natural gas.

3. The method according to claim 1 or claim 2, wherein the concentration of the supplementary fuel in the gas mixture is from 25% of the lower explosive limit to 70% of the lower explosive limit.

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

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

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

7. The method according to any one of claims 1 to 6, wherein the method further comprises heating the gas mixture before delivering the gas mixture to the regenerator through the distributor.

8. The method according to any one of claims 1 to 7, wherein reacting the feed stream comprises carrying out a dehydrogenation reaction and a hydrogen combustion reaction.

9. The method according to any one of claims 1 to 7, wherein reacting the feed stream comprises carrying out a cracking reaction.

10. The method according to any one of claims 1 to 7, wherein reacting the feed stream comprises carrying out a dehydration reaction.

11. The method according to any one of claims 1 to 7, wherein reacting the feed stream comprises carrying out a methanol to olefins reaction.

12. The method according to any one of claims 1 to 11, wherein the product stream comprises one or more of ethylene, propylene or butene.

13. The method according to any one of claims 1 to 12, wherein the product stream comprises at least 30% by weight of light olefins.

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