Method for dehydrogenating hydrocarbons utilizing a combustion unit
Patent Information
- Application Number
- JP2025508461
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-09-14
- Filing Date
- 2023-09-12
- Publication Date
- 2026-09-09
AI Technical Summary
Existing dehydrogenation processes for producing olefin compounds are inefficient and require high heat loads, leading to increased costs due to the need for additional fuel and downstream separation steps.
A co-current flow pattern in a combustion unit is employed, where particulate solids and gases move upward, with oxygen-containing gas entering below fuel, allowing partial oxidation of the oxygen carrier material before exposure to fuel, and the use of a circulating fluidized bed reactor system for dehydrogenation.
This approach reduces the need for external fuel by utilizing the exothermic combustion of hydrogen to generate heat, optimizing heat balance, and enhancing the production of olefin compounds while minimizing costs.
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Abstract
Description
[Technical Field]
[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Patent Application No. 63 / 406,447, filed September 14, 2022, which is incorporated herein by reference in its entirety.
[0002] FIELD OF THE INVENTION FIELD OF THE INVENTION Embodiments described herein relate generally to chemical processing, and more particularly to processes and systems utilized for the dehydrogenation of chemical species. [Background technology]
[0003] Olefin compounds can be used as base materials to produce many types of goods and materials. For example, ethylene can be used to make polyethylene, ethylene chloride, or ethylene oxide. Such products can be used in packaging products, construction, fibers, etc. Therefore, there is an industrial demand for olefin compounds such as ethylene, propylene, butene, and styrene. Summary of the Invention
[0004] One method of producing olefinic compounds is by dehydrogenating hydrocarbons. The dehydrogenation reaction may be facilitated by reacting hydrogen with oxygen to form water, thereby reducing or eliminating the hydrogen formed during dehydrogenation, which shifts the equilibrium toward olefinic compound production. In such embodiments, an oxygen carrier material may be utilized to provide oxygen for reaction with the hydrogen. The oxygen carrier material may be included in a particulate solid. Such oxygen carrier material may be circulated through a reactor and combustion unit, where a fuel may be combusted to heat at least the oxygen carrier material.
[0005] As described herein, it has been discovered that it can be beneficial to utilize a co-flow pattern for particulate solids and gases in a combustion unit. In particular, embodiments described herein include a flow pattern in which particulate solids move generally upward through the combustion unit, and gases, such as fuel and oxygen-containing gas, move generally upward. Furthermore, the oxygen-containing gas and fuel may enter the combustion unit through first and second gas inlets, respectively. The first gas inlet (for oxygen-containing gas) may be positioned below the second gas inlet (for fuel) so that the oxygen-carrier material contacts the oxygen-containing gas upstream of its initial contact with the fuel. Such an arrangement may allow the oxygen-carrier material to be at least partially oxidized before being exposed to fuel in the combustion unit.
[0006] According to one or more embodiments described herein, hydrocarbons can be dehydrogenated by a process comprising contacting a feed stream comprising one or more hydrocarbons with particulate solids in a dehydrogenation reactor. The particulate solids can include an oxygen carrier material. In the dehydrogenation reactor, the one or more hydrocarbons can be dehydrogenated to form hydrogen and one or more products. At least a portion of the hydrogen can react with oxygen from the oxygen carrier material to form water, reducing the oxygen content in the oxygen carrier material. The process can further include sending the particulate solids from the dehydrogenation reactor to a combustion unit. The particulate solids can move in a generally upward direction through the combustion unit, and the gas can move in a generally upward direction through the combustion unit, such that the particulate solids and the gas move through the combustion unit in a co-current pattern. The combustion unit can include a first gas inlet and a second gas inlet. The first gas inlet can be located below the second gas inlet. The oxygen-containing gas can enter the combustion unit through the first gas inlet. The fuel can enter the combustion unit through the second gas inlet. In a region of the combustion unit above the first gas inlet and below the second gas inlet, the oxygen content of at least a portion of the particulate solid oxygen-carrying material may be increased. In a region of the combustion unit above the second gas inlet, at least a portion of the fuel may react with oxygen from one or both of the oxygen-containing gas or the particulate solid oxygen-carrying material. The process may further include passing at least a portion of the particulate solids from the combustion unit to a dehydrogenation reactor.
[0007] It should be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and features of the claimed subject matter. Additional features and advantages of the embodiments are set forth in the detailed description, and in part will become readily apparent to those skilled in the art from that description, including the accompanying drawings and claims, or can be learned by practicing the described embodiments. The drawings are included to provide a further understanding of the embodiments and, together with the detailed description, serve to explain the principles and operation of the claimed subject matter. However, the embodiments shown in the drawings are illustrative and exemplary in nature and are not intended to limit the claimed subject matter. [Brief explanation of the drawings]
[0008] Reference will now be made in more detail to various embodiments, some of which are illustrated in the accompanying drawings. [Figure 1] 1 illustrates a schematic diagram of a reactor system according to one or more embodiments of the present disclosure. [Figure 2] 10A and 10B illustrate schematic diagrams of another reactor system according to additional embodiments of the present disclosure.
[0009] 1 and 2, many valves, temperature sensors, electronic controllers, etc., which are available and well known to those skilled in the art, are not included. Additionally, accompanying components often included within such reactor systems, such as air supplies, heat exchangers, surge tanks, etc., are also not included. However, it should be understood that these components are within the scope of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION
[0010] Specific embodiments of the present application will now be described. However, this disclosure may be embodied in different forms and should not be construed as limited to the embodiments set forth in this disclosure. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present subject matter to those skilled in the art.
[0011] Embodiments of the presently disclosed method are described in detail herein with reference to the reactor system of Figures 1 and 2 operating as a circulating fluidized bed process for dehydrogenating hydrocarbons. 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. For example, the concepts described herein may be equally applicable to other systems with alternative reactor and combustion units, such as those operating under non-fluidized conditions or those including a downer rather than a riser, and vice versa. Furthermore, it should be understood that not all parts of the reactor system of Figures 1 and 2 should be construed as essential to the claimed subject matter. Furthermore, although the method steps recited in the appended claims are described herein in connection with the reactor system of Figures 1 and 2, it should be understood that such recited method steps are adaptable to other systems as would be understood by one of ordinary skill in the art.
[0012] Referring now to FIG. 1 , an exemplary reactor system 100 that may be suitable for use with the methods described herein is shown schematically. The reactor system 100 may include a dehydrogenation reactor 110 and a combustion unit 150. A feed stream 102 may be fed into the dehydrogenation reactor 110. Particulate solids 180 may be fed into the dehydrogenation reactor 110 via stream 152. The particulate solids 180 may be contacted with the feed stream 102 in the dehydrogenation reactor 110. The particulate solids 180 may include an oxygen carrier material. The feed stream 102 may include one or more hydrocarbons that may be dehydrogenated in the dehydrogenation reactor 110 to form one or more products and hydrogen. The oxygen from the oxygen carrier material may react with the hydrogen to form water. The one or more products may exit the dehydrogenation reactor 110 via product stream 114.
[0013] Particulate solids 180 may exit dehydrogenation reactor 110 and be sent to combustion unit 150 via stream 112. Combustion unit 150 may include a first gas inlet 160 and a second gas inlet 170. First gas inlet 160 may be located below second gas inlet 170. Oxygen-containing gas 162 may enter combustion unit 150 through first gas inlet 160, and fuel 172 may enter combustion unit 150 through second gas inlet 170. Particulate solids 180 may travel in a generally upward direction through combustion unit 150, first through first gas inlet 160 and then through second gas inlet 170. Gases within combustion unit 150, such as oxygen-containing gas 162 and fuel 172, may travel in a generally upward direction through combustion unit 150, such that particulate solids 180 and gases travel through combustion unit 150 in a generally co-current pattern. Particulate solids 180 may then exit combustion unit 150 via stream 152 and be sent back to dehydrogenation reactor 110 .
[0014] In some embodiments, reactor system 100 may be operable to perform a circulating fluidized bed (CFB) dehydrogenation process. The CFB dehydrogenation process may include a dehydrogenation reactor 110 and a combustion unit 150, both of which are fluidized bed based.
[0015] As previously mentioned, in one or more embodiments, the feed stream 102 may be sent into the dehydrogenation reactor 110. In one or more embodiments, the feed stream 102 may include one or more hydrocarbons. In one or more embodiments, the one or more hydrocarbons may include an alkyl moiety. As used in this disclosure, a hydrocarbon includes an "alkyl moiety" if the molecule has at least one carbon-carbon single bond that can be dehydrogenated to form a carbon-carbon double bond. In one or more embodiments, the one or more hydrocarbons may include one or more of ethane, propane, butane, or ethylbenzene. According to one or more embodiments, the one or more hydrocarbons may include at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or even at least 99% ethane by weight. In additional embodiments, the one or more hydrocarbons can comprise at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or even at least 99% by weight of propane. In additional embodiments, the one or more hydrocarbons can comprise at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or even at least 99% by weight of butane. In additional embodiments, the one or more hydrocarbons can comprise at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or even at least 99% by weight of ethylbenzene. In additional embodiments, the one or more hydrocarbons may comprise a total of at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or even at least 99% by weight of ethane, propane, butane, and ethylbenzene.
[0016] According to additional embodiments, the dehydrogenation reactor 110 may be operated in a "backmixed" mode, where the feed stream 102 enters the reactor in a manner that is very close to isothermal. Thus, the fluid velocity in this region may be low enough, and the particulate solids 180 flow rate may be high enough, so that a dense bed may form at or around where the feed stream 102 is injected. In some embodiments, the superficial velocity of the reactor may be between 3 and 80 ft / s, such as between 3 and 40 ft / s, or between 10 and 30 ft / s. The flow rate of the particulate solids 180 in the reactor may be between 1 and 300 lb / ft 2 -s, e.g., 40-200 lb / ft 2 -s, or 60-160 lb / ft 2 -s, etc. The reactor may include multiple diameters and may include one or more frustums to increase or decrease the velocity of the particulate solids 180 and / or gaseous reactants. The reactor may operate at a gas residence time of 0.1 to 10 seconds, such as, for example, 0.5 to 6 seconds.
[0017] Particulate solids 180 may be utilized in the general operation of reactor system 100. As used herein, the term "particulate solids" may refer to one or more solid particles suitable for fluidization. In one or more embodiments, particulate solids 180 may include an oxygen carrier material and a dehydrogenation catalyst material. In some embodiments, particulate solids 180 may consist essentially of an oxygen carrier material. As used herein, "consisting essentially of" refers to a material that contains less than 1 wt. % of an unlisted material (i.e., consisting essentially of A means that A is at least 99 wt. % of the composition). In some embodiments, particulate solids 180 may be free of a dehydrogenation catalyst material. In some embodiments, the oxygen carrier material and the dehydrogenation catalyst material may be separate particles of particulate solids 180. In some embodiments, the oxygen carrier material and the dehydrogenation catalyst may be contained within the same particle of particulate solids 180.
[0018] In embodiments in which the particulate solids 180 include a dehydrogenation catalyst, the dehydrogenation of the one or more hydrocarbons may be at least partially by catalytic dehydrogenation. Catalytic dehydrogenation is the dehydrogenation of hydrocarbons facilitated by the use of a dehydrogenation catalyst. In embodiments in which the particulate solids 180 do not include a dehydrogenation catalyst, the dehydrogenation of the one or more hydrocarbons may be by non-catalytic thermal dehydrogenation. Non-catalytic thermal dehydrogenation refers to the dehydrogenation of hydrocarbons that does not use a dehydrogenation catalyst, and instead may occur through elevated temperatures, pressures, or a combination thereof.
[0019] In some embodiments, particulate solids 180 may include a "dual-purpose material" that can act as both a dehydrogenation catalyst and an oxygen-carrying material. It should be understood that, at least in the embodiments described herein in which an oxygen-carrying material and a dehydrogenation catalyst are utilized in the same reactor vessel (such as that of FIG. 1), such a dual-purpose material may be utilized in place of or in combination with the oxygen-carrying material of particulate solids 180 or the dehydrogenation catalyst of particulate solids 180.
[0020] Unless otherwise specified herein, "oxygen carrier material" may generally refer to an oxygen-rich oxygen carrier material or an oxygen-deficient oxygen carrier material. Unless otherwise specified herein, "dual-purpose material" may generally refer to an oxygen-rich dual-purpose material or an oxygen-deficient dual-purpose material. For example, an oxygen-deficient condition may exist after some oxygen is utilized for combustion, and the oxygen-deficient material may be oxygen-rich after regeneration and prior to combustion. The reaction may be carried out in one or more fluidized bed reactors, such as, for example, a circulating fluidized bed reactor. The reactor may be, for example, a riser or a downer.
[0021] As described herein, in one or more embodiments, the dehydrogenation catalyst and oxygen carrier material may be separate particles of particulate solids 180. One contemplated advantage of such a system is that the functionality of the system can be altered, even while the system is online, by adding, removing, or replacing one or both of the dehydrogenation catalyst and oxygen carrier material. For example, the reaction heat load can be adjusted by adding or removing one or both of the dehydrogenation catalyst and oxygen carrier material. This can be advantageous in some embodiments compared to dual-purpose materials, because the heat balance of dual-purpose particles must be determined prior to the reaction and cannot be easily adjusted by changing the amount of dehydrogenation catalyst relative to the oxygen carrier material. Controlling the ratio of dehydrogenation catalyst to oxygen carrier material can be even more advantageous, because reaction selectivity can be better fine-tuned. For example, the amount of hydrogen in the system can be used to control the degree of combustion, or the component balance can be used to optimize downstream separation processes.
[0022] In some embodiments, the dehydrogenation reactor 110 may include from 1 wt. % to 100 wt. % of the oxygen carrier material, such as from 5 wt. % to 95 wt. % or from 75 wt. % to 25 wt. % of the oxygen carrier material, based on the total weight of the particulate solids 180 in the dehydrogenation reactor 110. In other embodiments, the dehydrogenation reactor 110 may include from 50 wt. % to 75 wt. % of the oxygen carrier material, based on the total weight of the particulate solids 180 in the dehydrogenation reactor 110. In some embodiments, a relatively large amount of the oxygen carrier material may be present (e.g., at least 80 wt. %, at least 85 wt. %, or even at least 90 wt. %), particularly if the release of oxygen by the oxygen carrier material is relatively slow compared to the rate of dehydrogenation. In some embodiments, the dehydrogenation reactor 110 may include from 0 wt. % to 99 wt. % of the dehydrogenation catalyst, such as from 5 wt. % to 95 wt. % or from 25 wt. % to 75 wt. % of the particulate solids 180 in the dehydrogenation reactor 110. In other embodiments, dehydrogenation reactor 110 may include 25% to 50% by weight of dehydrogenation catalyst, based on the total weight of particulate solids 180 in dehydrogenation reactor 110. In some embodiments, dehydrogenation reactor 110 may include up to 95%, 99%, or even 100% by weight of the total weight of particulate solids 180 in dehydrogenation reactor 110 as dual-purpose material. For example, if utilized, all or a majority of the particulate solids 180 may be dual-purpose material. In embodiments, the particulate solids 180 material may include all solids in the system other than coke.
[0023] As previously mentioned, in dehydrogenation reactor 110, hydrogen may be contacted with an oxygen-rich oxygen carrier material in particulate solids 180. The oxygen carrier material may include one or more metal oxides. According to one or more embodiments, the one or more metal oxides may be redox-active metal oxides or mixtures of redox-active metal oxides. Redox-active metal oxides include binary, ternary, or other mixed metal oxides that can 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 metal oxide is a metal MO xwhere M can be one or more metals from IUPAC Groups 6, 7, 8, 9, 10, 11, or 12, and "x" is the number of bonded oxygen atoms in the structure. For example, the redox-active metal oxide can be Mn2O3, Fe2O3, Co3O4, CuO, (LaSr)CoO3, (LaSr)MnO3, Mg6MnO8, MgMnO3, MnO2, Fe3O4, Mn3O4, Cu2O, NiO, Ni2O3, CrO, Cr2O3, CrO2, ZnO, or any combination of other IUPAC Group 6-12 metal oxides. In some embodiments, the redox-active metal oxide can be cerium oxide. For example, the redox-active metal oxide can be CeO2, Ce2O3, or any other mixed metal oxide containing cerium. In further embodiments, the oxygen carrier material may include lanthanum oxide, La2O3, in combination with other reducible metal oxides. In some embodiments, the redox-active 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. In other embodiments, the oxygen carrier material may be formulated using redox-active metal oxides and binder and / or support materials to produce a flowable material with required physical properties, such as particle size distribution, density, and wear resistance. The binder and / or support material may include alumina, silica, titania, magnesia, zirconia, or a combination thereof.
[0024] In one or more embodiments, the oxygen carrier material may include a hydrogen-selective oxygen carrier material, which may include a promoter or a combination of various promoters. The addition of a promoter may result in the formation of a core-shell morphology. The promoter may include a compound containing an alkali metal oxide or alkaline earth metal oxide from IUPAC Groups 1 and 2, and / or an alkali transition metal oxide or alkaline earth transition metal oxide. In some embodiments, the alkali element may include one or more of sodium, lithium, potassium, and cesium. In some embodiments, the alkaline earth element may include one or more of calcium, magnesium, strontium, and barium. In some embodiments, the transition metal may include one or more of tungsten and molybdenum. For example, the one or more alkali transition metal oxides or alkaline earth transition metal oxides can be Na2WO4, K2MoO4, Na2MoO4, K2WO4, Li2WO4, CsWO4, Li2MoO4, CaWO4, CaMoO4, MgWO4, MgMoO4, SrWO4, SrMoO4, BaWO4, and BaMoO4. In some embodiments, the promoter can include one or more alkali metal or alkaline earth metal salts selected from Group 1 and Group 2 metal cations and a counterion. In some embodiments, the alkali element can include one or more of sodium, lithium, potassium, and cesium. In some embodiments, the alkaline earth element can include one or more of calcium, magnesium, strontium, and barium. In some embodiments, the counterion can include carbonate, sulfate, sulfite, sulfide, phosphate, phosphite, and borate.For example, the alkali metal salt or alkaline earth metal salt can be Na2CO3, Na2SO4, Na3PO4, Li2CO3, Li2SO4, Li3PO4, K2CO3, K2SO4, K3PO4, Cs2CO3, Cs2SO4, Cs3PO4, CaCO3, CaSO4, Ca3(PO4)2, SrCO3, SrSO4, Sr3(PO4)2, MgCO3, MgSO4, Mg3(PO4)2, BaCO3, BaSO4, Ba3(PO4)2, Na2HPO4, KHSO4, Na2SO3, K2B4O7, Na3BO3, or combinations thereof.
[0025] For example, oxygen carrier materials such as those disclosed in U.S. Patent Application No. 62 / 725,504, filed August 31, 2018, entitled "METHODS OF PRODUCING HYDROGEN-SELECTIVE OXYGEN CARRIER MATERIALS," and U.S. Patent Application No. 62 / 725,508, filed August 31, 2018, entitled "HYDROGEN-SELECTIVE OXYGEN CARRIER MATERIALS AND METHODS OF USE," are contemplated as suitable for the processes of the present disclosure, the teachings of which are incorporated herein by reference. In one or more additional embodiments, the oxygen carrier material may include the oxygen carrier materials of U.S. Patent No. 5,430,209, U.S. Patent No. 7,122,495, and / or WO 2018 / 232133, each of which is incorporated by reference in its entirety.
[0026] The oxygen-rich oxygen carrier material may be reducible by releasing oxygen, which may be selective for the combustion of hydrogen. For example, the oxygen carrier material may be selective for the combustion of hydrogen over hydrocarbons. In some embodiments, the oxygen-rich oxygen carrier material comprises about 1% to about 20% by weight of releasable oxygen, based on the total weight of the oxygen-rich oxygen carrier material. In other embodiments, the oxygen-rich oxygen carrier material comprises about 1% to about 10% by weight, about 1% to about 5% by weight, about 5% to about 20% by weight, or about 5% to about 10% by weight of releasable oxygen. As used herein, "releasable oxygen" may refer to oxygen that can be released via redox by the oxygen carrier material. Other oxygen may be present in the oxygen carrier material that is not releasable via redox. It should be understood that in some embodiments, oxygen may be released from the surface of the oxygen carrier material simultaneously with the combustion of hydrogen on the surface of the oxygen carrier material.
[0027] As previously mentioned, the releasable oxygen of an oxygen-rich oxygen carrier material can be selective for the combustion of hydrogen over hydrocarbons. In some embodiments, at least about 60% of the releasable oxygen of the oxygen carrier material is selective for hydrogen combustion. In other embodiments, at least about 55% of the releasable oxygen of the oxygen carrier material is selective for hydrogen combustion.
[0028] In embodiments, contacting hydrogen with an oxygen-rich oxygen carrier material removes a portion of the releasable oxygen from the oxygen-rich oxygen carrier material. In some embodiments, contacting hydrogen with an oxygen-rich oxygen carrier material removes about 1% to about 50% by weight of the releasable oxygen from the oxygen-rich oxygen carrier material. In other embodiments, contacting hydrogen with an oxygen-rich oxygen carrier material removes about 10% to about 50% by weight, about 10% to about 25% by weight, or about 25% to about 50% by weight of the releasable oxygen from the oxygen-rich oxygen carrier material.
[0029] In further embodiments, when hydrogen contacts the oxygen-rich oxygen carrier material, the oxygen-rich oxygen carrier material combusts greater than about 50% of the hydrogen. In other embodiments, when hydrogen contacts the oxygen-rich oxygen carrier material, the oxygen-rich oxygen carrier material combusts about 50% to about 90%, or about 75% to about 90%, of the hydrogen produced.
[0030] When the oxygen-rich oxygen carrier material is contacted with hydrogen, the hydrogen may combust and form an oxygen-depleted oxygen carrier material. To form the oxygen-depleted oxygen carrier material, at least a portion of the oxygen-rich oxygen carrier material may be reduced to a lower oxidation state. After the oxygen carrier material is reduced to form the oxygen-depleted oxygen carrier material, the oxygen-depleted oxygen carrier material may be discharged from the dehydrogenation reactor 110 in the lower oxidation state.
[0031] As described herein, in one or more embodiments, the particulate solid 180 may include a dehydrogenation catalyst. In one or more embodiments, the dehydrogenation catalyst may include gallium, chromium, and / or platinum. As described herein, the gallium and / or platinum dehydrogenation catalyst includes gallium, platinum, or both. The dehydrogenation catalyst may be supported on an alumina or alumina silica support and may optionally include potassium. In one or more embodiments, the dehydrogenation catalyst may include a catalyst disclosed in U.S. Pat. No. 8,669,406, which is incorporated herein by reference in its entirety, such as a Ga, Cr, and / or Fe-based catalyst. According to additional embodiments, a Pt-based catalyst may be utilized. In one or more embodiments, the catalysts disclosed in EP 0948475 B1 and / or WO 2010 / 133565 may be utilized, each of which is incorporated herein by reference in its entirety. Additional catalyst embodiments contemplated as suitable for use in the systems and methods described herein include those described in U.S. Patent No. 8,669,406, which is incorporated herein by reference in its entirety. Such catalysts may contain relatively small amounts of Cr, such as less than 6%, or about 1.5%. However, it should be understood that other suitable dehydrogenation catalysts may be utilized to carry out the dehydrogenation reaction.
[0032] In one or more embodiments, the dehydrogenation catalyst may exhibit suitable stability in the presence of steam. As described herein, combustion of hydrogen may form steam, which may directly contact the dehydrogenation catalyst. It is contemplated that not all dehydrogenation catalysts are equally effective in a steam environment. In one or more embodiments, dehydrogenation catalysts are utilized that maintain a substantial amount of their reactivity and / or selectivity for dehydrogenation of light alkanes. For example, one or more of the dehydrogenation catalysts utilized in the systems and methods of the present disclosure may not degrade alkane conversion and / or selectivity in dehydrogenation by more than 25%, more than 20%, more than 15%, more than 10%, more than 5%, or may even have improved alkane conversion and / or selectivity in dehydrogenation when in the presence of steam in amounts consistent with operation of the systems of the present disclosure. In some embodiments, the dehydrogenation catalyst may function at such conversion and / or selectivity when exposed to at least 10 mol% water (e.g., 10 mol% to 50 mol% water) for a period of up to 120 seconds (the time the catalyst may be exposed to such conditions according to some embodiments of the disclosed systems).
[0033] Suitable examples of dehydrogenation catalysts can be prepared to meet the definition of Geldart A. In some embodiments, the dehydrogenation catalyst is modified with silica, preferably having an average particle size of about 100 square meters per gram (m) as determined by the BET method. 2 gallium and platinum supported on alumina in the delta or theta phase, or the delta+theta phase, or theta+alpha phase, or mixed delta+theta+alpha phase, having a surface area of less than 100 ppm / g. In another embodiment, the dehydrogenation catalyst comprises 0.1 to 34 wt. % gallium oxide (Ga2O3), preferably 0.2 to 3.8 wt. %; 1 to 300 wt. ppm platinum, preferably 50 to 300 wt. ppm; 0 to 5 wt. % alkali and / or alkaline earth, e.g., potassium; 0.08 to 3 wt. % silica; and the balance up to 100 wt. % alumina.
[0034] In one or more embodiments, heat may be gained or lost by the dehydrogenation reaction, and the reoxidation of the oxygen-depleted oxygen carrier material and the reduction of the oxygen-rich oxygen carrier material may generate or use heat (i.e., may be exothermic or endothermic). In one or more embodiments, contacting the hydrocarbon feed with the dehydrogenation catalyst may be endothermic, resulting in a dehydrogenation heat loss. In some embodiments, contacting the hydrogen with the oxygen-rich oxygen carrier material may be exothermic, resulting in a combustion heat gain. The reoxidation of the oxygen-depleted oxygen carrier material may be exothermic, resulting in an oxygenation heat gain. Thus, by incorporating hydrogen combustion during catalytic dehydrogenation, in some embodiments, sufficient heat may be generated during the reoxidation of the oxygen-depleted oxygen carrier material to serve as a heat source for the alkane-to-olefin reaction. Thus, because the heat captured throughout the process by reoxidation of the oxygen carrier material, combustion of hydrogen, or both, can generate the amount of heat necessary for the reaction of alkanes or alkylaromatics to olefins, embodiments of the disclosed process may enable higher alkane conversion rates while reducing or eliminating the need for fuel gas required for conventional cracking.
[0035] As described herein, "dehydrogenation heat loss" refers to the amount of heat lost due to the dehydrogenation of the feed alkane, "combustion heat gain" refers to the amount of heat generated by the combustion of hydrogen, and "oxygenation heat gain" refers to the amount of heat generated by the oxidation of the oxygen-depleted oxygen carrier material. In one or more embodiments, the combustion heat gain may provide heat to the system that accounts for at least a portion of the dehydrogenation heat loss. In further embodiments, fuel 172 may be combusted to heat one or more of the dehydrogenation catalyst or the oxygen carrier material. The fuel 172 may compensate for any shortcomings in the heat generated by the combustion of hydrogen or the oxygenation of the oxygen carrier material. However, it should be understood that in the disclosed embodiments, the amount of fuel 172 required may be substantially less than that which would be required in a system not incorporating an oxygen carrier material.
[0036] Producing olefinic compounds by conventional dehydrogenation processes (e.g., those that do not incorporate hydrogen combustion) can be relatively expensive due to the high heat load required for the endothermic dehydrogenation reaction and / or downstream separation steps that may be required to separate unreacted hydrocarbons and remove the hydrogen produced in the dehydrogenation reaction. Regarding heat input reduction, catalytic dehydrogenation processes are generally endothermic and require heat. However, the exothermic combustion of hydrogen can offset that heat input requirement to some extent. Furthermore, if the oxygen content of the oxygen carrier material is reduced after combustion, it may be regenerated to regain oxygen for the oxygen carrier material, and the regeneration may be exothermic. This exothermic regeneration step may further offset the heat input requirement to sustain the dehydrogenation reaction. In some embodiments, the heat generated by the oxygen carrier regeneration and combustion reaction may fully compensate for the heat required for the endothermic dehydrogenation reaction and other heat demands, such as heating the feed gas (air, hydrocarbons, etc.) or balancing heat losses, or may at least reduce the need for any fuel 172 in the system. For further generalized information regarding dehydrogenation reactions incorporating hydrogen combustion, those skilled in the art are directed, for example, to U.S. Patent Application Publication No. 2021 / 0292259(A1), the teachings of which are incorporated herein by reference in their entirety.
[0037] 1 , during operation of dehydrogenation reactor 110 of reactor system 100, feed stream 102 may enter a riser within dehydrogenation reactor 110, and product stream 114 may exit reactor system 100 via stream 114. According to one or more embodiments, reactor system 100 may operate by feeding a chemical feed (e.g., in feed stream 102, such as feed stream 102) into dehydrogenation reactor 110.
[0038] According to one or more embodiments, particulate solids 180 may be fed into dehydrogenation reactor 110 via stream 152. Particulate solids 180 may include an oxygen-rich oxygen carrier material. Particulate solids 180 may also include a dehydrogenation catalyst. Feed stream 102 may contact particulate solids 180 in dehydrogenation reactor 110. Each of feed stream 102 and particulate solids 180 may flow upwardly into and pass through dehydrogenation reactor 110 to produce one or more products, an oxygen-depleted oxygen carrier material, and hydrogen. In dehydrogenation reactor 110, one or more hydrocarbons in feed stream 102 may be dehydrogenated to form one or more products and hydrogen. Additionally, in dehydrogenation reactor 110, hydrogen may contact an oxygen-rich oxygen carrier material in dehydrogenation reactor 110. The oxygen-rich oxygen carrier material may be reducible. Contacting the oxygen-rich oxygen carrier material with hydrogen can combust the hydrogen and reduce the oxygen carrier material to form an oxygen-depleted oxygen carrier material and water.
[0039] In one or more embodiments, one or more products may exit dehydrogenation reactor 110 via product stream 114. Stream 114 may be further processed, such as by one or more subsequent separation steps, or may be further reacted. It is contemplated that stream 114 may be utilized as a feed for another reactor system 100 or sold as a chemical product. In embodiments, one or more products in stream 114 may be combined with water produced from reacting hydrogen produced during the dehydrogenation of one or more hydrocarbons with oxygen from the oxygen carrier material. In some embodiments, water may be removed from stream 114 and one or more products utilizing a condenser.
[0040] As noted above, in some embodiments, stream 114 may include one or more products. In one or more embodiments, the one or more products may include one or more olefinic compounds. As used herein, the term "olefinic compound" refers to a hydrocarbon having one or more carbon-carbon double bonds, separate from the formal double bonds in aromatic compounds. For example, ethylene and styrene are olefinic compounds, but ethylbenzene is not an olefinic compound because the only double bonds present in ethylbenzene are formal double bonds present as part of the aromatic structure. In one or more embodiments, the one or more olefinic compounds may include one or more of ethylene, propylene, butylene, or styrene. In some embodiments, product stream 114 may include at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% ethylene. In additional embodiments, stream 114 may comprise at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or even at least 99% by weight propylene. In additional embodiments, stream 114 may comprise at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or even at least 99% by weight butylenes. In additional embodiments, stream 114 may comprise at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or even at least 99% by weight styrene. In additional embodiments, stream 114 may comprise, in total, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or even at least 99% by weight of one or more of ethylene, propylene, butylene, and styrene.
[0041] In some embodiments, the one or more products and particulate solids 180 may be sent to a separation device in a separation section within dehydrogenation reactor 110. In a separation device within dehydrogenation reactor 110, such as a stripper (not shown in FIG. 1 ), the particulate solids 180 may be separated from the one or more products. The one or more products may then be transported out of the separation section of dehydrogenation reactor 110. For example, separated vapors may be removed from dehydrogenation reactor 110 via a pipe at a gas outlet port of the separation section within dehydrogenation reactor 110. According to one or more embodiments, the separation device may be a cyclone separation system. The cyclone separation system may include two or more stages of cyclone separation.
[0042] In one or more embodiments, the dehydrogenation reactor 110 may operate at a vapor residence time in the fluidized bed reactor of less than 10 seconds (such as less than 9 seconds, less than 8 seconds, less than 7 seconds, less than 6 seconds, less than 5 seconds, less than 4 seconds, or even less than 3 seconds).
[0043] In one or more embodiments, the dehydrogenation reactor 110 can operate at a temperature of 550°C or greater and 800°C or less. In some embodiments, the temperature in the dehydrogenation reactor 110 can be 625°C or between 650°C and 770°C. In other embodiments, the temperature in the dehydrogenation reactor 110 can be between 700°C and 750°C. Without being bound by any particular theory, it is believed that if the temperature is too low (e.g., below 550°C), equilibrium constraints may limit the maximum hydrocarbon conversion rate and slow the rate of dehydrogenation due to heat and catalytic components. If the temperature is too low, the rate of oxygen release from the oxygen carrier material may also be slow, and hydrogen combustion may also be reduced. On the other hand, high temperatures (e.g., above 800°C) may cause thermal degradation of the desired products produced, resulting in lower product selectivities than are economically feasible. In some embodiments, the primary feed components can be propane, ethylbenzene, and / or butane, and the dehydrogenation reactor 110 can operate at temperatures above 600°C. In an additional embodiment, the primary feed component may be ethane and the dehydrogenation reactor 110 may operate at a temperature of at least 625°C.
[0044] In some embodiments, dehydrogenation reactor 110 may operate at a pressure of at least atmospheric pressure (approximately 14.7 psia). In some embodiments, dehydrogenation reactor 110 may operate at a pressure of approximately 500 psia. In other embodiments, dehydrogenation reactor 110 may operate at a pressure of from about 4 psia to about 160 psia, from about 20 psia to about 100 psia, or from about 30 psia to about 80 psia. In some embodiments, combustion unit 150 and regeneration unit 210 may operate within 30 psia of the pressure of dehydrogenation reactor 110.
[0045] The residence time of the particles in the dehydrogenation reactor 110 can typically vary from 0.5 seconds (sec) to 360 seconds. In other embodiments, the residence time of the particulate solids 180 can be from about 0.5 seconds to about 200 seconds, from about 0.5 seconds to about 100 seconds, from about 0.5 seconds to about 50 seconds, or from about 0.5 seconds to about 20 seconds.
[0046] In additional embodiments, the ratio of particulate solids 180 in dehydrogenation reactor 110 to feed stream 102 on a weight-to-weight (w / w) basis can range from 5 to 150. In some embodiments, the ratio can range from 10 to 40, such as from 12 to 36, or from 12 to 24.
[0047] In additional embodiments, the flow rate of particulate solids 180 is 1 pound per square foot per second (lb / ft ) in the upstream reactor section. 2 -s)(approx. 4.89kg / m 2 -s)~300lb / ft 2 -s(about 97.7kg / m 2 -s), e.g., 1 to 20 lb / ft 2 -s, etc., and in the downstream reactor section may be 1 lb / ft 2 -s(about 48.9kg / m 2 -s)~300lb / ft 2 -s(about 489kg / m 2 -s), e.g., 10-100 lb / ft 2 -s, etc.
[0048] In one or more embodiments, particulate solid 180 may be capable of fluidization. In some embodiments, particulate solid 180 may exhibit what is known in the industry as "Geldart A" or "Geldart B" properties. Particles may be classified as "Group A" or "Group B" according to D. Geldart, Gas Fluidization Technology, John Wiley & Sons (New York, 1986), 34-37, and D. Geldart, "Types of Gas Fluidization," Powder Technol. 7 (1973) 285-292, which are incorporated herein by reference in their entireties.
[0049] Group A is understood by those skilled in the art to represent aerated powders with bubble-free fluidization; high bed expansion; slow, linear degassing rate; bubble characteristics where splitting / re-coalescing bubbles may predominate, with maximum bubble size and large wake; high levels of solids mixing and gas backmixing assuming equal U-Umf (where U is the carrier gas velocity and Umf is the minimum fluidization velocity, typically but not necessarily measured in meters per second, m / s, i.e., excess gas velocity exists); axisymmetric slug characteristics; and no eruptions except in very shallow beds. Assuming equal cfp, the listed properties tend to improve as the average particle size decreases; or as the fraction less than 45 micrometers (μm) increases; or as the gas pressure, temperature, viscosity, and density increase. Generally, particles with small average particle size and / or low particle density (1.4 grams per cubic centimeter, g / cm) 3 They exhibit a viscosity of less than 1000 psi, are easily fluidized with smooth fluidization at low gas velocities, and may exhibit controlled bubbling with small bubbles even at higher gas velocities.
[0050] Group B starts to foam at Umf; shows moderate bed expansion; rapid degassing; no restriction on bubble size; assuming U-Umf is equal, the levels of solid mixing and gas backmixing are moderate; both axisymmetric and asymmetric slags; and jets only in shallow beds; is understood by those skilled in the art as representing a "sand-like" powder. These characteristics tend to improve as the average particle size decreases, but the particle size distribution, and with some uncertainty, the gas pressure, temperature, viscosity, or density do not appear to contribute much to the improvement of the above characteristics. Generally, most of the particles have a particle size (cfp) of 40μm < cfp < 500μm when the density (ρp) is 1.4 < pp < 4 g / cm 3 and preferably 60μm < cfp < 500μm when the density (ρp) is 4 g / cm 3 and 250μm < cfp < 100μm when the density (ρp) is 1 g / cm 3 .
[0051] 1 , in one or more embodiments, particulate solids 180 and gas products may be separated within dehydrogenation reactor 110 by high-efficiency cyclones in a stripping section (not shown in FIG. 1 ) of reactor system 100. The stripping section may be within reactor 110 or may be a separate vessel. In the described embodiment, particulate solids 180 may be sent to combustion unit 150 via Stream 112. In some embodiments, the dehydrogenation catalyst, the oxygen carrier material, or both may be stripped with a displacement gas, such as nitrogen, steam, methane, natural gas, or other suitable gas, in the stripping section before being sent to combustion unit 150. In some embodiments, a portion of particulate solids 180 may be sent from the stripping section via Stream 116 to Stream 152 for reuse in reactor 110 without first passing through regeneration unit 150. Without being bound by theory, it is believed that by recycling a portion of the particulate solids 180 back to the reactor 110, the oxygen content of the oxygen carrier material may be better controlled because the oxygen carrier material may have more time to react to release its oxygen, thereby allowing the oxygen carrier material to supply more oxygen to the reactor. It is also believed that recycling the particulate solids 180 may allow for improved temperature control of the reactor 110 because recycling the particulate solids 180 may improve temperature control of the material entering the reactor 110, which may improve the temperature profile of the reactor 110.
[0052] In some embodiments, the dehydrogenation catalyst of the particulate solids 180 may be slightly deactivated after contacting the feed stream 102. In other embodiments, the dehydrogenation catalyst of the particulate solids 180 may still be suitable for reaction in the dehydrogenation reactor 110. As used herein, "deactivated" may refer to a catalyst contaminated with materials such as coke at a temperature lower than that required to promote reaction of the feedstock, or an oxygen-carrying material that is deficient in oxygen. In some embodiments, contaminants such as coke may be deposited on the particulate solids 180 sent from the dehydrogenation reactor 110 to the combustion unit 150.
[0053] Particulate solids 180 may enter combustion unit 150 via stream 112. Particulate solids 180 may pass through first gas inlet 160, through which oxygen-containing gas 162 enters combustion unit 150, and then through air zone 164. Air zone 164 is so named for simplicity because air may be utilized as the oxygen-containing gas. Next, particulate solids 180 may pass through second gas inlet 170, through which fuel 172 enters combustion unit 150. Above second gas inlet 170 may be fuel zone 174, which contains the fuel and any oxygen unreacted in air zone 164. Particulate solids 180 then exit combustion unit 150 via stream 152 and may be sent back to dehydrogenation reactor 110. Generally, in the air zone 164, the oxygen carrier material may be oxidized, and in the fuel zone, the fuel may be combusted with any remaining oxygen unreacted in the air zone and oxygen from the oxygen carrier material.
[0054] In combustion unit 150, conditions may remove contaminants such as coke, increase the temperature of particulate solids 180, increase the oxygen content of the oxygen-carrying material of particulate solids 180, decrease the oxygen content of the oxygen-carrying material of particulate solids 180, or a combination thereof. In some embodiments, coke on particulate solids 180 may be removed by combustion in an oxygen-containing environment within combustion unit 150. In further embodiments, particulate solids 180 may be heated to a target temperature by fuel 172. Particulate solids 180 may then be circulated back to dehydrogenation reactor 110, thereby carrying the heat required for the dehydrogenation reaction. For further generalized information regarding dehydrogenation carried out in a fluidized bed, the skilled artisan is referred to, for example, U.S. Patent Application Publication No. 2005 / 0177016(A1); WO 2005 / 077867(A1) (corresponding to U.S. Patent Application Publication No. 2008 / 0194891(A1)); and WO 20107591A1.
[0055] The oxygen carrier may be oxidized or reduced when utilized in the dehydrogenation process. Different oxidation states of the oxygen carrier may behave differently within the dehydrogenation process. For example, an oxygen carrier with a lower oxidation state may not combust hydrogen as efficiently within the dehydrogenation reaction as an oxygen carrier with a relatively higher oxidation state. Conversely, an oxygen carrier with a relatively high oxidation state may be more likely to oxidize hydrocarbons during the dehydrogenation reaction compared to an oxygen carrier with a relatively low oxidation state, potentially harming the production of olefins from the process. Passing the oxygen carrier through the combustion unit 150 may help control the oxidation state of the oxygen carrier material.
[0056] In some embodiments, the oxygen-depleted oxygen carrier material of particulate solids 180 can be reoxidized to an oxidation state higher than the oxidation state of the oxygen-depleted oxygen carrier material by combustion in an oxygen-containing environment in combustion unit 150. In some embodiments, the oxygen-containing environment can be air. In some embodiments to form an oxygen-rich oxygen carrier material, the oxygen-depleted oxygen carrier material can be restored to its original oxidation state. In some embodiments, the oxygen-depleted oxygen carrier material can have an oxidation state of +2, +3, or +4. The oxygen-rich oxygen carrier material can then be cycled back to dehydrogenation reactor 110, carrying the heat required for the dehydrogenation reaction. In other embodiments, nitrogen or steam can also be used to transport the oxygen-rich oxygen carrier material to dehydrogenation reactor 110.
[0057] In one or more embodiments, fuel 172 may be combusted in combustion unit 150 to generate heat, which may increase the temperature of particulate solids 180. The heat generated by the oxidation of the oxygen-depleted oxygen-carrying material and the combustion of fuel 172 may be sufficient to maintain the temperature of dehydrogenation reactor 110 at a desired temperature. Because particulate solids 180 enter and may impart its temperature to dehydrogenation reactor 110, the desired temperature may depend on the minimum temperature required to operate dehydrogenation reactor 110.
[0058] In one or more embodiments, combustion unit 150 may operate at a temperature of 650°C or even 700°C to 900°C, such as 725°C to 875°C, or 750°C to 850°C. Generally, combustion unit 150 may have a temperature at least 50°C higher than the temperature of dehydrogenation reactor 110. Such a temperature range may be utilized such that the temperature of dehydrogenation reactor 110 can be maintained with a limited amount of dehydrogenation catalyst and / or oxygen carrier material. Furthermore, such temperatures may be necessary to activate the dehydrogenation catalyst, if utilized.
[0059] The residence time of particulate solids 180 within combustion unit 150 can typically vary from 0.5 seconds to 240 seconds. In other embodiments, the residence time of particulate solids 180 can be from about 0.5 seconds to about 200 seconds, from about 0.5 seconds to about 100 seconds, from about 0.5 seconds to about 50 seconds, or from about 0.5 seconds to about 20 seconds.
[0060] As described herein, in one or more embodiments, particulate solids 180 may be sent from dehydrogenation reactor 110 to combustion unit 150 via stream 112. According to embodiments, particulate solids 180 and gases within combustion unit 150 may move in a generally upward direction. As used in this disclosure, the term "generally upward direction" means that the average velocity of particulate solids 180 and gases within that section of reactor system 100 is in an upward direction, where the upward direction opposes the attractive force of gravity. As an average, the velocities of gas molecules or individual particles of particulate solids 180 within a section of reactor system 100 may have a distribution and may not equal the average, but overall, the velocity of gases and / or particulate solids 180 will average generally upward. In embodiments, particulate solids 180 and gases may move through combustion unit 150 in a co-current pattern.
[0061] In one or more embodiments, the combustion unit 150 may include a first gas inlet 160 and a second gas inlet 170 above the first gas inlet 160. As used herein, a "gas inlet" refers to any component operable to inject gas into the combustion unit 150. For example, the gas inlet may be a blower or a distributor. Additionally, other suitable gas suppliers are contemplated herein, as known to those skilled in the art. According to embodiments, an oxygen-containing gas 162 may enter the combustion unit 150 via the first gas inlet 160. In some embodiments, the oxygen-containing gas 162 may be air, enriched air, air mixed with steam, or flue gas. Enriched air is air to which oxygen gas has been added. In some embodiments, the oxygen-containing gas 162 may include at least 28 mole percent oxygen. In other embodiments, the oxygen-containing gas 162 is between about 2 mol% and about 28 mol% oxygen, between about 2 mol% and about 25 mol%, between about 2 mol% and about 20 mol%, between about 2 mol% and about 15 mol%, between about 2 mol% and about 10 mol%, between about 2 mol% and about 5 mol%, between about 5 mol% and about 28 mol%, between about 5 mol% and about 25 mol%, between about 5 mol% and about 20 mol%, between about 5 mol% and about 15 mol%, or between about 5 mol% It may contain about 10 mol%, about 10 mol% to about 28 mol%, about 10 mol% to about 25 mol%, about 10 mol% to about 20 mol%, about 10 mol% to about 15 mol%, about 15 mol% to about 28 mol%, about 15 mol% to about 25 mol%, about 15 mol% to about 20 mol%, about 20 mol% to about 28 mol%, about 20 mol% to about 25 mol%, or about 25 mol% to about 28 mol% of oxygen.
[0062] In embodiments, the oxygen-containing gas 162 may enter the combustion unit 150 in a generally upward direction. In some embodiments, the oxygen-containing gas 162 may initially enter the combustion unit 150 in a downward direction before following the generally upward flow of other gases within the combustion unit 150. In some embodiments, the directional flow of the oxygen-containing gas 162 into the combustion unit 150 may cause the oxygen concentration in the region above the first gas inlet 160 to be higher than in other regions of the combustion unit 150, such that the region above the first gas inlet 160 may be an air zone 164. In one or more embodiments, the oxygen concentration in the air zone 164 may be greater than 25 molar percent. In other embodiments, the oxygen concentration in the air zone 164 may be between about 4 molar percent and about 28 molar percent oxygen, between about 4 molar percent and about 21 molar percent, between about 4 molar percent and about 10 molar percent, between about 10 molar percent and about 28 molar percent, between about 10 molar percent and about 21 molar percent, or between about 21 molar percent and about 28 molar percent oxygen. Because air is often the least costly oxygen-containing gas available, the name air is used herein simply to indicate the presence of oxygen.
[0063] In one or more embodiments, the oxygen content of at least a portion of the oxygen-carrying material of the particulate solids 180 may increase in a region above the first gas inlet 160 but below the second gas inlet 170. For example, the oxygen content of at least a portion of the oxygen-carrying material of the particulate solids 180 may increase in the air zone 164.
[0064] In one or more embodiments, fuel 172 may enter combustion unit 150 through second gas inlet 170. In some embodiments, fuel 172 may initially enter combustion unit 150 in a downward direction before following the flow of other gases in combustion unit 150 in a generally upward direction. In some embodiments, fuel 172 may include hydrogen, methane, ethane, propane, natural gas, or combinations thereof. According to embodiments, fuel 172 may enter combustion unit 150 in a generally upward direction. In embodiments, at least a portion of fuel 172 in a region above second gas inlet 170 may react with oxygen from the oxygen-carrying material of particulate solids 180, oxygen-containing gas 162, or both to generate heat and increase the temperature of particulate solids 180. The region above the second gas inlet 170 may be a fuel zone 174 because the directional flow of fuel 172 into the combustion unit 150 may cause the concentration of fuel 172 in the region above the second gas inlet 170 to be higher than the concentration of fuel 172 in the region below the first gas inlet 160 or the region below the second gas inlet 170.
[0065] In some embodiments, the concentration of fuel 172 in fuel zone 174 can be less than 20 mol%. In some embodiments, the concentration of fuel 172 in fuel zone 174 can be between about 0.1 mol% and about 15 mol%, between about 0.1 mol% and about 10 mol%, between about 0.1 mol% and about 5 mol%, between about 0.1 mol% and about 1 mol%, between about 0.1 mol% and about 0.5 mol%, between about 0.5 mol% and about 20 mol%, between about 0.5 mol% and about 15 mol%, between about 0.5 mol% and about 1 ...0 mol%, between about 0.5 mol% and about 10 mol%, between about 0.5 mol% and about 10 mol%, between about It may be about 5 mol%, about 0.5 mol% to about 1 mol%, about 1 mol% to about 20 mol%, about 1 mol% to about 15 mol%, about 1 mol% to about 10 mol%, about 1 mol% to about 5 mol%, about 5 mol% to about 20 mol%, about 5 mol% to about 15 mol%, about 5 mol% to about 10 mol%, about 10 mol% to about 20 mol%, about 10 mol% to about 15 mol%, or about 15 mol% to about 20 mol%.
[0066] In one or more embodiments, at least a portion of the particulate solids 180 may exit the combustion unit 150 via stream 152 and be sent back to the dehydrogenation reactor 110. In some embodiments, sending at least a portion of the particulate solids 180 from the combustion unit 150 to the dehydrogenation reactor 110 may include separating the particulate solids 180 from the flue gas produced in the combustion unit 150 prior to sending the particulate solids 180 into the dehydrogenation reactor 110. In one or more embodiments, at least a portion of the oxygen-carrying material of the particulate solids 180 may exit the combustion unit 150 at least partially reoxidized. In one or more embodiments, at least a portion of the oxygen-carrying material of the particulate solids 180 may exit the combustion unit 150 at least partially reduced.
[0067] Without being bound by theory, it is believed, according to one or more embodiments, that combustion unit 150 may be most effectively utilized when the oxygen-carrying material of particulate solids 180 has a sufficient fuel burn rate in reduced form. For example, if the oxygen-carrying material is reduced, it may be able to burn fuel 172 in the combustion zone sufficiently to heat particulate solids 180 for use in dehydrogenation reactor 110. Materials that do not have a sufficient fuel burn rate in reduced form may not be able to burn fuel 172 in combustion unit 150 sufficiently to heat particulate solids 180 for use in dehydrogenation reactor 110. It is believed that performing fuel combustion in the combustion zone may better prevent fuel 172 and combustion products, such as carbon dioxide and water, from entering downstream processes, including the oxidation zone or dehydrogenation reactor 110, and may allow for easier disposal of the combustion products and unburned fuel by allowing all required combustion of fuel 172 to occur in a single, isolated unit of reactor system 100.
[0068] It is also believed that the use of combustion unit 150 can help control the oxidation state of the oxygen carrier material. The co-flow of gas and particulate solids 180, along with the specific placement of the gas inlet within combustion unit 150, allows at least a portion of the oxygen carrier material to be re-oxidized before entering the region of combustion unit 150 at a higher fuel concentration. By adjusting the concentrations of oxygen and fuel within combustion unit 150, the oxidation state of the oxygen carrier material upon exiting combustion unit 150 can be higher or lower than the oxidation state of the oxygen carrier material upon entering combustion unit 150. This flexibility may allow reactor system 100 using combustion unit 150 to more easily adjust to changing conditions within dehydrogenation reactor 110 to maintain selectivity and productivity of the dehydrogenation reaction, compared to reactor systems that do not include combustion unit 150.
[0069] Referring now to reactor system 200 of Figure 2, a reactor system according to an additional embodiment of the present disclosure is shown. Particulate solids 180 may be sent from dehydrogenation reactor 110 to combustion unit 150 via stream 112. Particulate solids 180 may then be sent from combustion unit 150 to regeneration unit 210 via stream 152. Next, particulate solids 180 may enter gas / solid separator 218 within regeneration unit 210. Particulate solids 180 may be separated from flue gas produced in combustion unit 150 by gas / solid separator 218. The flue gas may then exit regeneration unit 210 via stream 214. Particulate solids 180 may then travel down through regeneration unit 210 and pass through third gas inlet 220 through which oxygen-containing gas 222 enters regeneration unit 210. The particulate solids 180 may then travel through a fourth gas inlet 230 through which a stripping gas 232 enters the regeneration unit 210. The particulate solids 180 may then exit the regeneration unit 210 and be sent back to the dehydrogenation reactor 110 via stream 212.
[0070] As described herein, in one or more embodiments, particulate solids 180 may be sent from combustion unit 150 to regeneration unit 210 via stream 152. In regeneration unit 210, particulate solids 180 may pass through gas / solid separator 218. According to one or more embodiments, separator 218 may be a riser end system, which may include a cyclone separation system. In embodiments in which the riser end system includes a cyclone separation system, a portion of particulate solids 180 may be discharged from the riser end system without first passing through the cyclone separation system. A cyclone separation system may include two or more stages of cyclone separation. In embodiments in which separator 218 includes two or more cyclone separation stages, 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 designations VSS (available from UOP), LD2 (available from Stone and Webster), and RS2 (available from Stone and Webster). Primary cyclones are described, for example, in U.S. Pat. Nos. 4,579,716, 5,190,650, and 5,275,641, each of which is incorporated herein by reference in its entirety. In some separation systems utilizing a primary cyclone as the primary cyclone separator, one or more sets of additional cyclones, such as secondary and tertiary cyclones, are used to further separate the particulate solids from the product gas. It should be understood that any primary cyclone separator may be used in embodiments of the present invention. The particulate solids 180 may be separated from an exhaust gas, such as a flue gas. The gas separated from the particulate solids 180 may be mixed with the gas from the regeneration unit 210 and exit the regeneration unit 150 via exhaust stream 214 .
[0071] According to embodiments, the particulate solids 180 may move in a generally downward direction through the regeneration unit 210. As used in this disclosure, the term "generally downward direction" means that the average velocity of the particulate solids 180 is in a downward direction, where the downward direction is due to gravity. As an average, the velocities of individual particles of the particulate solids 180 may have a distribution and may not equal the average, but overall, the velocity of the particulate solids 180 averages generally downward. According to embodiments, the gas within the regeneration unit 210 may move in a generally upward direction through the regeneration unit 210. According to embodiments, the particulate solids 180 and the gas may move in a countercurrent pattern through the regeneration unit 210.
[0072] In one or more embodiments, the regeneration unit 210 may include a third gas inlet 220 and a fourth gas inlet 230 below the third gas inlet 220. According to embodiments, oxygen-containing gas 222 may enter the regeneration unit 210 via the third gas inlet 220. In some embodiments, the oxygen-containing gas 222 may be air, enriched air, air mixed with steam, or flue gas. Enriched air is air with oxygen gas added. In some embodiments, the oxygen-containing gas 222 may contain less than 28 mole percent oxygen. In other embodiments, the oxygen-containing gas 222 is between about 2 mol% and about 28 mol% oxygen, between about 2 mol% and about 25 mol%, between about 2 mol% and about 20 mol%, between about 2 mol% and about 15 mol%, between about 2 mol% and about 10 mol%, between about 2 mol% and about 5 mol%, between about 5 mol% and about 28 mol%, between about 5 mol% and about 25 mol%, between about 5 mol% and about 20 mol%, between about 5 mol% and about 1 ...8 mol%, between about 5 mol% and about 20 mol%, between about 5 mol% and about 28 mol%, between about 5 mol% and about 25 mol%, between about 5 mol% and about 20 mol%, between about 5 mol% and about 15 mol%, between about 5 mol% and about 28 mol%, between about 5 mol% and about 28 mol%, between about 5 mol% and about 20 mol%, between about 5 mol% and about 28 mol%, between about 5 mol% and about 20 mol%, between about 5 mol% and about 28 mol%, between % to about 10 mol%, about 10 mol% to about 28 mol%, about 10 mol% to about 25 mol%, about 10 mol% to about 20 mol%, about 10 mol% to about 15 mol%, about 15 mol% to about 28 mol%, about 15 mol% to about 25 mol%, about 15 mol% to about 20 mol%, about 20 mol% to about 28 mol%, about 20 mol% to about 25 mol%, or about 25 mol% to about 28 mol% of oxygen.
[0073] In embodiments, the oxygen-containing gas 222 may enter the regeneration unit 210 in a generally upward direction. In some embodiments, the directional flow of the oxygen-containing gas 222 into the regeneration unit 210 may result in a higher oxygen concentration in the region above the third gas inlet 220 than in other regions of the regeneration unit 210, such that the region above the third gas inlet 220 may be the air zone 224. In one or more embodiments, the oxygen concentration in the air zone 224 may be greater than 25 mol%. In other embodiments, the oxygen concentration in the air zone 224 may be between about 4 mol% and about 28 mol% oxygen, between about 4 mol% and about 21 mol%, between about 4 mol% and about 10 mol%, between about 10 mol% and about 28 mol%, between about 10 mol% and about 21 mol%, or between about 21 mol% and about 28 mol% oxygen. Because air is often the least costly oxygen-containing gas to utilize, the term air is used herein simply to indicate the presence of oxygen.
[0074] In one or more embodiments, the regeneration unit 210 may include a fourth gas inlet 230. In embodiments, the stripping gas 232 may enter the regeneration unit 210 through the fourth gas inlet 230. In embodiments, the fourth gas inlet 230 may be located below the third gas inlet 220. In embodiments, the stripping gas 232 may exit the fourth gas inlet 230 in a generally upward direction. Thus, in embodiments, the directional flow of the stripping gas 232 into the regeneration unit 210 may cause the concentration of the stripping gas 232 to be higher in the region above the fourth gas inlet 230 and below the third gas inlet 220, such that the region above the fourth gas inlet 230 and below the third gas inlet 220 may be the strip zone 234. In some embodiments, the stripping gas 232 may include nitrogen, steam, or a combination thereof.
[0075] In one or more embodiments, stripping gas 232 may include a reducing agent. In one or more embodiments, the reducing agent may include hydrogen, methane, or a combination thereof. In some embodiments, particulate solids 180 may be exposed to the reducing agent in stripping gas 232 in strip zone 234, and the oxygen content of at least a portion of the oxygen-carrying material of particulate solids 180 may be reduced. In some embodiments, the concentration of the reducing agent in stripping gas 232 may be greater than 10 mole %. In some embodiments, the concentration of the reducing agent in stripping gas 232 may even be greater than 90 mole %.In some embodiments, the concentration of the reducing agent in the stripping gas 232 is about 1 mol % to about 100 mol %, e.g., about 1 mol % to about 90 mol %, about 1 mol % to about 80 mol %, about 1 mol % to about 70 mol %, about 1 mol % to about 60 mol %, about 1 mol % to about 50 mol %, about 1 mol % to about 40 mol %, about 1 mol % to about 30 mol %, about 1 mol % to about 20 mol %, about 1 mol % to about 10 mol %, about 10 mol % to about 100 mol %, or about 10 mol % to about 90 mol%, about 10 mol% to about 80 mol%, about 10 mol% to about 70 mol%, about 10 mol% to about 60 mol%, about 10 mol% to about 50 mol%, about 10 mol% to about 40 mol%, about 10 mol% to about 30 mol%, about 10 mol% to about 20 mol%, about 20 mol% to about 100 mol%, about 20 mol% to about 90 mol%, about 20 mol% to about 80 mol%, about 20 mol% to about 70 mol%, about 20 mol% to about 60 mol%, about 20 mol% to about 50 mol%, about 20 mol% to about 40 mol%, about 20 mol% to about 30 mol%, about 30 mol% to about 100 mol%, about 30 mol% to about 90 mol%, about 30 mol% to about 80 mol%, about 30 mol% to about 70 mol%, about 30 mol% to about 60 mol%, about 30 mol% to about 50 mol%, about 30 mol% to about 40 mol%, about 40 mol% to about 100 mol%, about 40 mol% to about 90 mol%, about 40 mol% to about 80 mol%, about 40 mol% to about 70 mol%, about 40 mol% to about 60 mol%, about 40 mol% to about 50 mol%, about 50 mol% to about 100 mol%, about 50 mol% to about 90 mol%, about 50 mol% to about 80 mol%, about 50 mol% to about 70 mol%, about 50 mol% to about 60 mol%, about 60 mol% to about 100 mol%, about 60 mol% to about 90 mol%, about 60 mol% to about 80 mol%, about 60 mol% to about 70 mol%, about 70 mol% to about 100 mol%, about 70 mol% to about 90 mol%, about 70 mol% to about 80 mol%, about 80 mol% to about 100 mol%, about 80 mol% to about 90 mol%, or about 90 mol% to about 100 mol%, etc.
[0076] In one or more embodiments, at least a portion of the particulate solids 180 may be removed from the regeneration unit 210 and passed through at least a portion of the regeneration unit 210 a second time before being passed through the dehydrogenation reactor 110. Thus, in some embodiments, at least a portion of the particulate solids 180 may be removed from the strip zone 234 and sent to the air zone 224. In one or more embodiments, at least a portion of the particulate solids 180 may be removed from the regeneration unit 210 and sent back to the combustion unit 150 via stream 216. At least a portion of the particulate solids 180 may be removed from any location in the regeneration unit 210, such as from a region above the third gas inlet 220, a region above the fourth gas inlet 230 and below the third gas inlet 220, a region below the fourth gas inlet 230, or a combination thereof.
[0077] In a first aspect of the present disclosure, hydrocarbons can be dehydrogenated by a method comprising contacting a feed stream containing one or more hydrocarbons with particulate solids in a dehydrogenation reactor. The particulate solids can include an oxygen carrier material. In the dehydrogenation reactor, the one or more hydrocarbons can be dehydrogenated to form hydrogen and one or more products. At least a portion of the hydrogen can react with oxygen from the oxygen carrier material to form water, reducing the oxygen content in the oxygen carrier material. The process can further include sending the particulate solids from the dehydrogenation reactor to a combustion unit. The particulate solids can move in a generally upward direction through the combustion unit, and the gas can move in a generally upward direction through the combustion unit, such that the particulate solids and the gas move through the combustion unit in a co-current pattern. The combustion unit can include a first gas inlet and a second gas inlet. The first gas inlet can be located below the second gas inlet. The oxygen-containing gas can enter the combustion unit through the first gas inlet. The fuel can enter the combustion unit through the second gas inlet. In a region of the combustion unit above the first gas inlet and below the second gas inlet, the oxygen content of at least a portion of the particulate solid oxygen-carrying material may be increased. In a region of the combustion unit above the second gas inlet, at least a portion of the fuel may react with oxygen from one or both of the oxygen-containing gas or the particulate solid oxygen-carrying material. The process may further include passing at least a portion of the particulate solids from the combustion unit to a dehydrogenation reactor.
[0078] A second aspect of the present disclosure may include the first aspect, wherein directing at least a portion of the particulate solids from the combustion unit to the dehydrogenation reactor includes separating the particulate solids from the flue gas.
[0079] A third embodiment includes any of the preceding embodiments or combinations of those embodiments, wherein the one or more hydrocarbons include an alkyl moiety and the one or more products include one or more olefinic compounds.
[0080] A fourth embodiment includes any of the preceding embodiments or combinations of those embodiments, wherein the one or more hydrocarbons include ethane and the one or more products include ethylene.
[0081] A fifth aspect includes any of the preceding aspects or combinations of those aspects, wherein the fuel includes hydrogen.
[0082] A sixth aspect of the present disclosure includes any of the preceding aspects or combinations of those aspects, wherein coke is deposited on particulate solids passed from the dehydrogenation reactor to a combustion unit, and at least a portion of the coke reacts with oxygen in the combustion unit.
[0083] A seventh aspect of the present disclosure includes any of the preceding aspects or combinations of those aspects, wherein passing at least a portion of the particulate solids from the combustion unit to the dehydrogenation reactor includes passing the particulate solids through a regeneration unit, wherein the particulate solids are exposed to an oxygen-containing gas in the regeneration unit, thereby increasing the oxygen content of at least a portion of the oxygen-carrying material of the particulate solids.
[0084] An eighth aspect of the present disclosure includes any of the preceding aspects or combinations of those aspects, wherein the particulate solids and oxygen-containing gas within the regeneration unit move in a countercurrent pattern.
[0085] A ninth aspect of the present disclosure includes any of the preceding aspects or combinations of those aspects, wherein the regeneration unit comprises third and fourth gas inlets, the oxygen-containing gas enters the regeneration unit through the third gas inlet, and the stripping gas enters the regeneration unit through the fourth gas inlet, and the stripping gas comprises the reducing agent in an amount between 0 mol% and 100 mol%.
[0086] A tenth aspect of the present disclosure includes any of the preceding aspects or combinations of those aspects, wherein a portion of the particulate solids is removed from the regeneration unit and passed through at least a portion of the regeneration unit a second time before being sent to the dehydrogenation reactor.
[0087] An eleventh aspect of the present disclosure includes any of the preceding aspects or combinations of those aspects, wherein the particulate solid consists essentially of the oxygen-carrying material.
[0088] A twelfth aspect of the present disclosure includes any of the preceding aspects or combinations of aspects, wherein the dehydrogenation of the one or more alkanes is carried out by non-catalytic thermal dehydrogenation.
[0089] A thirteenth aspect of the present disclosure includes any of the preceding aspects or combinations of those aspects, wherein the particulate solid further comprises a dehydrogenation catalyst material, and wherein the dehydrogenation of the one or more alkanes is effected at least in part by catalytic dehydrogenation.
[0090] A fourteenth aspect of the present disclosure includes any of the preceding aspects or combinations of those aspects, wherein the dehydrogenation catalyst material and the oxygen carrier material are separate particles of the particulate solid or are contained within the same particle of the particulate solid.
[0091] A fifteenth aspect of the present disclosure includes any of the preceding aspects or combinations of aspects, wherein the particulate solid is a Geldart Group A or Geldart Group B particulate.
[0092] It will be apparent to those skilled in the art that various modifications and variations can be made to the technology of the present disclosure without departing from the spirit and scope of the technology. Since combinations, subcombinations, and variations of the disclosed embodiments incorporating the spirit and substance of the technology of the present disclosure may occur to those skilled in the art, the technology should be construed as including all within the scope of the appended claims and their equivalents. Furthermore, although some aspects of the present disclosure may be identified herein as preferred or particularly advantageous, it is intended that the present disclosure is not limited to these aspects.
[0093] It should be noted that the various details described in this disclosure should not be construed as implying that these details relate to elements that are essential components of the various embodiments described in this disclosure, even if a particular element is illustrated in each of the drawings accompanying this specification. Unless specifically identified as such, features disclosed and described herein should not be construed as "essential." Contemplated embodiments of the present technology include those that include some or all of the features of the appended claims.
[0094] It should be noted that for purposes of describing and defining this disclosure, the term "about" is utilized in this disclosure to express the inherent degree of uncertainty that may result from any quantitative comparison, value, measurement, or other representation. The term "about" is also utilized in this disclosure to express the degree to which a quantitative representation may vary from the basis of description without resulting in a change in the basic functionality of the subject matter in question.
[0095] Where relevant, when a composition is described as "comprising" one or more elements, embodiments of the composition that "consist" or "consist essentially of" those one or more elements are contemplated herein.
[0096] It is understood that the compositional ranges of chemical components in a stream or reactor should, in some embodiments, be understood to contain a mixture of isomers of that component. For example, a compositional range specifying butene may include a mixture of various isomers of butene. It is understood that the examples provide compositional ranges for various streams, and that the total amount of isomers of a particular chemical composition may constitute a range.
[0097] It should be noted that one or more of the following claims utilize the term "where" or "wherein" as a transitional phrase. It should be noted that for purposes of defining the present technology, 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."
[0098] In some embodiments, a chemical or chemical stream is described as being "fed" from one system unit or portion of a system unit to another system unit or portion of a system unit. As described herein, such a feed may include a direct feed or an indirect feed. For example, when feeding from "unit A" to "unit B," a direct feed would have no intermediate destination between unit A and unit B (i.e., directly through a pipe or other transport passageway), while an indirect feed would include one or more intermediate destinations between unit A and unit B. For example, a stream fed from unit A to unit B may pass through, without limitation, a heat exchanger, a processing device, etc.
[0099] 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 application. When multiple ranges are given for quantitative values, these ranges may be combined to form larger ranges, which are contemplated in the embodiments described herein.
Claims
1. A method for dehydrogenating hydrocarbons, A feed stream containing one or more hydrocarbons is brought into contact with particulate solids in a dehydrogenation reactor, wherein the particulate solids contain an oxygen carrier material, and in the dehydrogenation reactor, The aforementioned one or more hydrocarbons are dehydrogenated to form hydrogen and one or more products. At least a portion of the hydrogen reacts with oxygen derived from the oxygen carrier material to form water, thereby reducing the oxygen content in the oxygen carrier material. Making contact, The process involves sending the particulate solid from the dehydrogenation reactor to the combustion unit, The particulate solid moves through the combustion unit in a generally upward direction, and the gas moves through the combustion unit in a generally upward direction, thereby causing the particulate solid and the gas to move through the combustion unit in a parallel flow pattern. The combustion unit comprises a first gas inlet and a second gas inlet, the first gas inlet being located below the second gas inlet, oxygen-containing gas entering the combustion unit through the first gas inlet, and fuel entering the combustion unit through the second gas inlet. In the region of the combustion unit above the first gas inlet and below the second gas inlet, the oxygen content in at least a portion of the particulate solid oxygen carrier material increases. In the region of the combustion unit above the second gas inlet, at least a portion of the fuel reacts with oxygen derived from either or both of the oxygen-containing gas and the particulate solid oxygen carrier material. Sending, Sending at least a portion of the particulate solid from the combustion unit to the dehydrogenation reactor, A method that includes this.
2. The method according to claim 1, wherein sending at least a portion of the particulate solid from the combustion unit to the dehydrogenation reactor includes separating the particulate solid from the flue gas.
3. The method according to claim 1, wherein the one or more hydrocarbons include an alkyl moiety, and the one or more products include one or more olefin compounds.
4. The method according to claim 1, wherein the one or more hydrocarbons include ethane, and the one or more products include ethylene.
5. The method according to claim 1, wherein the fuel includes hydrogen.
6. The method according to claim 1, wherein coke is deposited on particulate solid sent from the dehydrogenation reactor to the combustion unit, and at least a portion of the coke reacts with oxygen in the combustion unit.
7. The method according to claim 1, wherein sending at least a portion of the particulate solid from the combustion unit to the dehydrogenation reactor includes passing the particulate solid through a regeneration unit, the particulate solid being exposed to an oxygen-containing gas in the regeneration unit, thereby increasing the oxygen content in at least a portion of the oxygen carrier material of the particulate solid.
8. The method according to claim 7, wherein the particulate solid and the oxygen-containing gas in the regeneration unit move in a countercurrent pattern.
9. The method according to claim 7, wherein the regeneration unit comprises third and fourth gas inlets, the oxygen-containing gas enters the regeneration unit through the third gas inlet, the stripping gas enters the regeneration unit through the fourth gas inlet, and the stripping gas contains a reducing agent in an amount of 0 mol% to 100 mol%.
10. The method according to claim 7, wherein a portion of the particulate solid is removed from the regeneration unit and passes through at least a portion of the regeneration unit a second time before being sent to the dehydrogenation reactor.
11. The method according to claim 1, wherein the particulate solid essentially consists of the oxygen carrier material.
12. The method according to claim 1, wherein the dehydrogenation of one or more alkanes is carried out by non-catalytic thermal dehydrogenation.
13. The method according to claim 1, wherein the particulate solid further comprises a dehydrogenation catalyst material, and the dehydrogenation of the one or more alkanes is carried out at least partially by catalytic dehydrogenation.
14. The method according to claim 13, wherein the dehydrogenation catalyst material and the oxygen carrier material are separate particles of the particulate solid or are contained within the same particle of the particulate solid.
15. The method according to any one of claims 1 to 14, wherein the particulate solid is Geldart group A or Geldart group B particles.