Electrically Heated Carbon Monoxide Reactor

Abstract

A reactor and method are provided for performing a reverse water gas shift reaction of a feedstock containing CO and H2 to a first product gas containing CO, wherein a methanation reaction occurs in parallel with the reverse water gas shift reaction, and heat for the endothermic reverse water gas shift reaction is provided by resistive heating.

Description

[Technical Field]

[0001] Technical Field The present invention relates to a reactor system and method for producing gas from a feedstock comprising CO2 and H2 under reverse water gas shift reaction conditions in the presence of a catalyst. [Background technology]

[0002] background The production of syngas is typically carried out in large chemical plants due to the energy-intensive reactions required to drive its production, making small-scale production difficult. Additionally, the toxicity of syngas (particularly since it contains carbon monoxide) makes storing it difficult and fraught with risk.

[0003] There is a need for on-demand syngas production in small-scale plants that use easily storable reactants for syngas production and that use a relatively simple production setup with minimal operator input.

[0004] Systems and methods for carrying out endothermic catalytic reactions are described in co-pending patent application PCT / EP2019 / 062424. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] PCT / EP2019 / 062424 Summary of the Invention [Problem to be solved by the invention]

[0006] Furthermore, there is currently great interest in methods that can capture and utilize carbon dioxide, such as the reverse water-gas shift reaction (RWSG), with the goal of reducing atmospheric carbon dioxide emissions. Therefore, there is currently a strong need for improved reactors and processes for performing the RWSG reaction. The resulting synthesis gas can be used for a variety of applications, including methanol and synthetic fuels via Fischer-Tropsch synthesis. [Means for solving the problem]

[0007] overview Thus, in a first aspect, the present invention provides a reactor system for carrying out a reverse water-gas shift reaction to produce a first product gas comprising CO from a feedstock comprising CO and H, comprising: -Providing feedstocks containing CO2 and H2; -Structure catalyst having a macrostructure of conductive material and catalytically active material capable of catalyzing both the reverse water gas shift reaction and the methanation reaction; said structural catalyst configured to operate under a temperature and pressure such that both said reverse water-gas reaction and said methanation reaction occur; a pressure shell containing the structural catalyst, wherein the pressure shell includes an inlet for admitting the feedstock and an outlet for discharging product gas, the inlet positioned such that the feedstock enters the structural catalyst at a first end thereof and the product gas exits the structural catalyst at a second end thereof; - a thermal insulation layer provided between the structural catalyst and the pressure shell; at least two conductors electrically connected to the structural catalyst and a power source disposed outside the pressure shell; wherein the power source is dimensioned to pass an electric current through the macrostructure to heat at least a portion of the structural catalyst to a temperature of at least 500°C, and wherein the at least two conductors are connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than to the second end of the structural catalyst, and the structural catalyst is configured to pass an electric current from one conductor to the second end of the structural catalyst and back to the second ends of the at least two conductors; an outlet for the first product gas containing CO The reactor system comprising:

[0008] In a further aspect, there is provided a method for converting a feedstock comprising CO and H2 to a first product gas comprising CO in a reactor system comprising a pressure shell containing a structural catalyst comprising a macrostructure of an electrically conductive material and a catalytically active material; the reactor system comprising insulation between the structural catalyst and the pressure shell; and the method comprising the steps of: - providing a pressurized feedstock; - feeding the pressurized feedstock into the pressure shell through an inlet positioned at a first end of the structural catalyst such that the feedstock enters the structural catalyst; -using a catalytically active material capable of catalyzing both the reverse water gas shift reaction and the methanation reaction; - subjecting the feedstock to a reverse water gas shift reaction over the structured catalyst at a temperature and pressure such that both the reverse water gas shift reaction and the methanation reaction occur; - discharging a product gas from the pressure shell, wherein the product gas exits the structural catalyst at a second end of the structural catalyst; - providing electrical power through electrical conductors connecting a power source located outside the pressure shell to the structural catalyst, allowing electrical current to flow through the macrostructure, thereby heating at least a portion of the structural catalyst to a temperature of at least 500°C, the at least two conductors being connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than the second end of the structural catalyst, and the structural catalyst being configured to pass electrical current from one conductor substantially to the second end of the structural catalyst and back to a second conductor of the at least two conductors, thereby heating at least a portion of the structural catalyst to a temperature sufficient for the feedstock to undergo a reverse water gas shift reaction on the structural catalyst; Discharging a first product gas comprising CO from the reactor system.

[0009] In a further aspect, there is provided a method for rapidly switching a reverse water gas shift reaction of a feedstock comprising CO and H from a first steady-state reaction condition (A) to a second steady-state reaction condition (B) or vice versa in a reactor system described herein, said method comprising the steps of: In the first steady-state reaction condition (A), - feeding the feedstock into the reactor system at a first total flow rate; and - providing a first electrical power through an electrical conductor connecting a power source located outside the pressure shell to the structural catalyst, thereby causing a first electrical current to flow through the electrically conductive material; whereby at least a portion of the structural catalyst is heated to a first temperature at which the feedstock is converted over the structural catalyst under the first steady-state reaction conditions (A) into a first product gas; and discharging the first product gas from the reactor system; Then, under the second steady-state reaction conditions (B), - feeding the feedstock into the reactor system at a second total flow rate; and - providing a second electrical power through an electrical conductor connecting a power source located outside the pressure shell to the structural catalyst, thereby causing a second electrical current to flow through the electrically conductive material; thereby heating at least a portion of the structural catalyst to a second temperature; at which temperature the feedstock is converted over the structural catalyst under the second steady-state reaction conditions (B) into a second product gas; and discharging the second product gas from the reactor system; wherein the second power is greater than the first power; and / or the second total flow rate is greater than the first total flow rate.

[0010] Additional aspects of the present invention are described in the following detailed description, examples, and appended claims. [Brief explanation of the drawings]

[0011] Figure legend FIG. 1a is a diagram illustrating a cross section of one embodiment of a reactor system of the present invention with a structured catalyst comprising an array of macrostructures.

[0012] FIG. 1b shows the reactor system of FIG. 1a with the pressure shell and part of the insulation removed.

[0013] FIG. 2 is an enlarged view of a portion of the reactor system.

[0014] 3a and 3b are schematic cross-sectional views through one embodiment of the reactor system of the present invention containing a structured catalyst.

[0015] 4 and 5 are top and side views, respectively, showing an embodiment of a structural catalyst in which macrostructures are arranged.

[0016] FIG. 6 is a diagram showing one embodiment of the structural catalyst of the present invention.

[0017] 7 and 8 show an embodiment of a structural catalyst having a connector.

[0018] FIG. 9 shows the equilibrium composition from the reverse water gas shift and methanation reactions of CO2 and H2 as a function of temperature at 29 barg using a feedstock of 33.3% CO2 and 66.67% H2.

[0019] FIG. 10 is a diagram illustrating an embodiment of a reactor system and a method including feedstock preparation.

[0020] FIG. 11 is a diagram illustrating an embodiment of the process including feed preparation, a reactor system, an upgrading unit including flash separation and CO2 removal, and recycle of the off-gas stream.

[0021] FIG. 12 is a diagram illustrating an embodiment of the process including feed preparation, a reactor system, an upgrading unit including flash separation and membranes, and recycling of the off-gas stream.

[0022] FIG. 13 is a diagram illustrating an embodiment of the process including feed preparation, reactor system, flash separation, CO2 removal, and upgrading unit including cool box, and off-gas stream methods.

[0023] FIG. 14 shows experimental data from testing using one embodiment of a reactor system according to the present invention.

[0024] FIG. 15 illustrates simulation data for an embodiment of a reactor system according to the present invention.

[0025] FIG. 16a shows simulation data simulating an embodiment of a reactor system according to the present invention.

[0026] FIG. 16b shows simulation data for one embodiment of a reactor system according to the present invention.

[0027] FIG. 17 illustrates simulation data for one embodiment of a reactor system according to the present invention.

[0028] FIG. 18 shows experimental data using one embodiment of a reactor system according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] Detailed Disclosure Electrical heating provides a means for rapidly heating the reverse water-gas shift catalyst and enabling on-demand synthesis gas production. This allows for the rapid production of synthesis gas, for example, in chemical plants, to drive other chemical reactions from these molecules. Examples of such reactions include methanol, phosgene, acetic acid, and oxoalcohols. This method also uses readily storable reactants for synthesis gas production, enabling on-demand synthesis gas production in small plants with a relatively simple production setup and minimal operator input. It also provides a means for on-demand synthesis gas production to accommodate fluctuations in the power supply from renewable sources such as wind and solar.

[0030] This technology describes a method for the on-demand production of synthesis gas from CO2 and H2 under methanation and reverse water gas shift reaction conditions in an electrically heated reactor in a compact design.

[0031] Using the reverse water gas shift reaction: [ka]

[0032] In combination with the methanation reaction: [ka]

[0033] Generally, a catalyst using a catalytically active material containing nickel (Ni) or a noble metal can be used.

[0034] Compact electric reactors using monolithic catalysts are easy to operate and can use a simple startup principle, allowing gas to be generated only when needed. This allows gas to be produced in the amount needed, requires little gas storage, and reduces or completely eliminates gas transportation, making them relatively inexpensive plants. Furthermore, the simple reactors and ease of operation for methanation and reverse water-gas shift reactions make them attractive as non-local plants, reducing the risks of gas handling.

[0035] Furthermore, using electricity as a heat source allows for rapid start-up and shutdown (within minutes to hours), thus reducing the need for gas storage by almost instantly switching from standby to gas production and vice versa.

[0036] The present invention relates to a reactor system for performing a reverse water-gas shift reaction to produce a first product gas comprising CO from a feedstock comprising CO and H, said reactor system comprising: -Providing feedstocks containing CO2 and H2; -Structure catalyst having a macrostructure of conductive material and catalytically active material capable of catalyzing both the reverse water gas shift reaction and the methanation reaction; said structural catalyst configured to operate under a temperature and pressure such that both said reverse water-gas reaction and said methanation reaction occur; a pressure shell containing the structural catalyst, wherein the pressure shell includes an inlet for admitting the feedstock and an outlet for discharging product gas, the inlet positioned such that the feedstock enters the structural catalyst at a first end thereof and the product gas exits the structural catalyst at a second end thereof; - a thermal insulation layer provided between the structural catalyst and the pressure shell; at least two conductors electrically connected to the structural catalyst and a power source disposed outside the pressure shell; wherein the power source is dimensioned to pass an electric current through the macrostructure to heat at least a portion of the structural catalyst to a temperature of at least 500°C, and wherein the at least two conductors are connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than to the second end of the structural catalyst, and the structural catalyst is configured to pass an electric current from one conductor to the second end of the structural catalyst and back to the second ends of the at least two conductors; an outlet for the first product gas containing CO Includes.

[0037] In the reverse water gas shift reaction, the goal has traditionally been to suppress methanation, which occurs in parallel with the reverse water gas shift reaction. However, conventional catalysts with low reactivity for this reaction typically experience difficulties at temperatures above 500°C, where the methanation reaction rate increases. Because methanation is an undesirable side reaction that reduces the process gas yield, attempts are typically made to avoid or reduce it as much as possible. The present invention is based on the recognition that, in a reactor configuration such as that used in the present invention, it is possible to operate the reverse water gas shift reaction at such high temperatures that it is no longer necessary to avoid the methanation reaction, since all methane produced is subsequently converted to hydrogen, CO, and CO in the reverse methanation reaction. The present invention is further based on the recognition that a prerequisite for making this possible is the use of a catalyst that can catalyze both the reverse water gas shift and methanation.

[0038] The central aspect of a reverse water gas shift reactor is to promote the conversion of CO2 to CO, but avoid the further reaction of CO to carbon. This carbon can exist in the form of both carbon formed on the catalyst and carbon formed on the metal parts, called metal dusting. The central carbon-forming reactions considered in the conversion of CO2 to CO are the Boudouard reaction and the CO reduction reaction, which can be represented as follows:

[0039] [ka]

[0040] Both reactions are exothermic and consequently favored at low temperatures. The CO reduction reaction in particular poses a major challenge to promoting the reverse water-gas shift reaction, since the reverse water-gas shift reaction is intended to contain little or even no HO in the feed, reducing the potential for conversion via the reverse water-gas shift reaction. However, this also means that the potential for carbon production in the first part of the reverse water-gas shift reactor via the CO reduction reaction is high, since the combination of high H partial pressure and low HO partial pressure provides a high driving force for this reaction. In this regard, it is advantageous to carry out a parallel methanation reaction according to the following reaction scheme: [ka]

[0041] This reaction reduces the partial pressure of the generated CO and increases the partial pressure of HO, effectively reducing the possibility of the CO reduction reaction. Furthermore, since the adsorbed carbon atoms in the catalytic reaction mechanism are intermediates in the methanation reaction scheme, the risk of carbon formation on the catalyst from the CO reduction reaction is reduced if the methanation reaction is also carried out (see H.S. Bengaard, J.K. Norskov, J. Sehested, B.S. Clausen, L.P. Nielsen, A.M. Molenbroek, and J.R. Rostrup-Nielsen, "Steam Reforming and Graphite Formation on Ni Catalysts," Journal of Catalysis, Volume 209, Issue 2, 2002, Pages 365-384). This means that any carbon atoms formed on the catalyst surface can be hydrogenated to methane instead of polymerizing into a carbon layer. This is advantageous for designing functional catalysts. Finally, when methanation occurs simultaneously in a reverse water-gas shift reactor, it generates heat, releasing chemical energy to heat the system and resulting in a temperature increase. Because the CO reduction reaction is also exothermic, the temperature increase caused by the methanation reaction reduces the potential for CO reduction, and once the temperature rises to a certain level, the potential for CO reduction completely disappears. This exact level depends on the specific reactant concentrations, inlet temperature, and pressure, but typically ranges from 600 to 800 °C, above which CO reduction is no longer possible. It should be noted that the heat generated by the methanation reaction exhibits the highest temperature increase at the catalytically active sites on the surface of the catalyst, where carbon formation can occur. As a result, this heat generation has a significant positive effect on reducing carbon formation potential.

[0042] Overall, the configuration of the present invention allows for the promotion of the reverse water gas shift reaction and methanation reaction in a reactor system without carbon-forming side reactions on either the catalyst or metal surfaces, since the methanation reaction counteracts this. super , preferably 800°C super, more preferably 900°C super or 1000°C super A particular configuration of the reactor system, capable of raising the temperature to very high product gas temperatures, means that methane produced from the methanation reaction is generated in the first section of the reactor, but above approximately 600-800°C, this methane begins to be converted to CO2 and H2 products via the reverse methanation reaction. This configuration advantageously allows for the removal of some CO and the production of some HO in the catalyst layer in the temperature region where CO reduction is problematic, followed by the regeneration of CO in the higher temperature region with low or no carbon potential. Effectively, utilizing high product gas temperatures, in turn, means that the final product can be delivered with very low methane concentrations, even though methane has a peak concentration somewhere along the reaction zone. In embodiments, the reactor system is operated with no or very little methane in the feed and very little methane in the product gas, but with a peak methane concentration within the reaction zone higher than in the feed and / or product gas. In some cases, this peak methane concentration within the reaction zone can be an order of magnitude higher than the inlet and outlet methane concentrations.

[0043] In one embodiment of the reactor system of the present invention, the structural catalyst has a first reaction zone located closest to a first end of the structural catalyst, the first reaction zone having an exothermic reaction as a whole, and a second reaction zone located closest to a second end of the structural catalyst, the second reaction zone having an endothermic reaction as a whole, and the structural catalyst having an exothermic reaction as a whole. Preferably, the first reaction zone extends over 5% to 60% of the length of the structural catalyst from its first end to its second end. Here, reaction zone refers to the volume of the reactor system catalyzing the methanation reaction and the reverse water-gas shift reaction, estimated along the flow path through the catalyst area.

[0044] The combined activity for both reverse water gas shift and methanation in the reactor system of the present invention means that the reaction scheme inside the reactor starts as an exotherm in the first part of the reactor system and ends as an endotherm towards the outlet of the reactor system. This means that the heat of reaction (Q) added or removed during the reaction follows the typical heat balance of a plug flow reactor system. r ) related to: F.C. pm dT / dV=Q add +Q r =Q add +Σ(-Δ r H i )·(-r i )

[0045] where F is the flow rate of the process gas, C pm is the heat capacity, V is the volume of the reaction zone, T is the temperature, and Q add is the energy supply / removal from the surroundings, Q r is the energy input / removal associated with a chemical reaction, given as the sum of all chemical reactions catalyzed within a volume, calculated as the product of the reaction enthalpy and the reaction rate of a given reaction. In an embodiment of the reactor system of the present invention, the temperature of the feedstock at the inlet of the pressure shell is between 200°C and 500°C, preferably between 200°C and 400°C.

[0046] In an embodiment of the reactor system of the present invention, the concentration of methane in the partially catalyzed feedstock within at least a portion of the structured catalyst is higher than in the feedstock and the first product gas.

[0047] In an embodiment of the reactor system of the present invention, the temperature of the structural catalyst increases continuously from the first end to the second end of the structural catalyst.

[0048] The reactor system layout allows for a pressurized feedstock to be supplied to the reactor system at the inlet and the gas to be directed to the pressure shell of the reactor system. In one embodiment, the pressurized feedstock is provided by compressing the feedstock(s) in one or more compressors. In another embodiment, the pressurized feedstock is provided as an inlet gas stream from a different process. Inside the pressure shell, a configuration of insulating layers and inert materials is arranged to pass the feedstock through the structured catalyst and contact the catalytic material, which promotes the methanation and reverse water-gas shift reactions. Additionally, heating the structured catalyst can provide the heat required for the endothermic reactions. Product gas from the heated structured catalyst is directed to the outlet of the reactor system.

[0049] The proximity of the catalytically active material to the electrically conductive material allows efficient heating of the catalytically active material by close thermal conduction from the resistively heated electrically conductive material. Thus, a key feature of the resistive heating process is that the energy is supplied internally within the body itself, rather than by conduction, convection, or radiation from an external heat source. Furthermore, the hottest portion of the reactor system will be within the pressure shell of the reactor system. Preferably, the power supply and structural catalyst are sized so that at least a portion of the structural catalyst reaches a temperature of at least 500°C, preferably at least 900°C. The surface area of ​​the conductive material can be tailored to the specific reaction at given operating conditions.

[0050] The conductive material is preferably a macrostructure. As used herein, the term "macrostructure" refers to a structure large enough to be visible to the naked eye without magnification. The dimensions of the macrostructure are typically in the centimeter or even meter range. The dimensions of the macrostructure are advantageously made to correspond at least in part to the inner dimensions of the pressure shell housing the structural catalyst, thereby saving space for thermal insulation layers and conductors. Two or more macrostructures may be joined to provide an array of macrostructures having at least one outer dimension in the meter range, such as 2 m or 5 m. Such two or more macrostructures may be referred to as an "array of macrostructures." In this case, the dimensions of the array of macrostructures are advantageously manufactured to correspond at least in part to the inner dimensions of the pressure shell housing the structural catalyst (saving space for thermal insulation layers). Arrays of macrostructures are contemplated with dimensions of 0.1 to 10 m. 3 The structure catalyst can occupy a volume of 1000 or more. The structure catalyst can include a single macrostructure or an array of macrostructures, where the macrostructure (or multiple macrostructures) can support a ceramic coating that supports a catalytically active material. In an array of macrostructures, the macrostructures can be electrically connected to each other; however, alternatively, the macrostructures are not electrically connected to each other. Thus, the structure catalyst can be composed of two or more macrostructures arranged adjacent to each other. The macrostructure (or multiple macrostructures) can be an extruded and sintered structure, or a 3D-printed structure. The 3D-printed macrostructure can be provided with or without subsequent sintering.

[0051] The physical dimensions of the macrostructures may be any suitable dimensions, so the height may be less than the width of the macrostructures or vice versa.

[0052] The macrostructure can support a ceramic coating, and the ceramic coating can support a catalytically active material. The term "macrostructure supporting a ceramic coating" is intended to indicate that the macrostructure is coated with a ceramic coating on at least a portion of the surface of the macrostructure. Therefore, this term does not mean that the entire surface of the macrostructure is coated with the ceramic coating, but rather that at least the portion of the macrostructure electrically connected to the conductor is free of the coating. The coating can be a ceramic material having pores in its structure, which allows the catalytically active material to be supported on and within the coating. Advantageously, the catalytically active material comprises catalytically active particles having a size ranging from about 2 nm to about 250 nm. The proportion of the conductive material coated with the ceramic coating, the type and structure of the ceramic coating, and the amount and composition of the catalytically active material can be tailored to the specific reaction under given operating conditions.

[0053] Preferably, the macrostructure is fabricated by extruding a mixture of powdered metal particles and a binder into an extruded structure and then sintering the extruded structure, thereby providing a material with a high geometric surface area per volume. Preferably, the extruded structure is sintered in a reducing atmosphere to provide the macrostructure. Alternatively, the macrostructure is 3D printed using a metal additive manufacturing fusion process, i.e., a 3D printing process, that does not require subsequent sintering, such as powder bed fusion or direct energy deposition processes. Examples of such powder bed fusion or direct energy deposition processes include laser beam, electron beam, or plasma 3D printing processes. Alternatively, the macrostructure may be fabricated as a 3D metal structure using a binder-based metal additive manufacturing process and then sintered at a first temperature T1 (T1 > 1000°C) in a non-oxidizing atmosphere to provide the macrostructure.

[0054] Before the second sintering in an oxidizing atmosphere, a ceramic coating containing catalytically active material is applied to the macrostructure, forming a chemical bond between the ceramic coating and the macrostructure. Alternatively, the ceramic coating can be impregnated with the catalytically active material after the second sintering. The formation of a chemical bond between the ceramic coating and the macrostructure results in particularly high thermal conductivity between the electrically heated macrostructure and the catalytically active material supported by the ceramic coating, allowing for close and nearly direct contact between the heat source and the catalytically active material of the structural catalyst. The proximity of the heat source and the catalytically active material ensures effective heat transfer, allowing for highly efficient heating of the structural catalyst. This allows for a compact reactor system, and therefore a compact reactor system containing the structural catalyst, in terms of gas throughput per reactor system volume.

[0055] As used herein, the terms "3D printing" and "3D printing" are meant to refer to metal additive manufacturing processes. Such metal additive manufacturing processes cover 3D printing processes in which materials are bonded to structures under computer control to create three-dimensional objects, where the structures are solidified, for example, by sintering, to provide a macrostructure. Furthermore, such metal additive manufacturing processes also include 3D printing processes that do not require subsequent sintering, such as powder bed fusion processes or direct energy deposition processes. Examples of such powder bed fusion or direct energy deposition processes include laser beam, electron beam, or plasma 3D printing processes.

[0056] Because the reactor system does not require a furnace, the overall reactor size can be significantly reduced.

[0057] In embodiments, the conductive material is one or more elements selected from the group consisting of Fe, Ni, Cu, Co, Cr, Al, Si, and alloys thereof. Such alloys may contain additional elements such as Mn, Y, Zr, C, Co, Mo, or combinations thereof. Preferably, the conductive material comprises Fe, Cr, Al, or alloys thereof. Such alloys may contain additional elements such as Si, Mn, Y, Zr, C, Co, Mo, or combinations thereof. Preferably, the catalytically active material is a particle having a size of 2 nm to 250 nm. Preferably, the conductor and conductive material are made of different materials than the conductive material. The conductor may be, for example, iron, nickel, aluminum, copper, silver, or alloys thereof. The ceramic coating is an electrically insulating material and will typically have a thickness of about 100 μm, e.g., in the range of 10 to 500 μm.

[0058] The conductive material is preferably a coherent or coherently interconnected material to achieve electrical conductivity throughout the conductive material, thereby achieving thermal conductivity throughout the structure catalyst, and in particular, to provide heating of the catalyst material. A coherent or coherently interconnected material can ensure uniform distribution of current within the conductive material, and therefore uniform distribution of heat within the structure catalyst. Throughout this text, the term "coherent" is synonymous with cohesiveness and is therefore meant to refer to a coherently interconnected or coherently bonded material. The effect of the structure catalyst being a coherent or coherently interconnected material is to provide control over the connectivity within the structure catalyst material, and therefore the conductivity of the conductive material. It should be noted that the conductive material is still referred to as a coherent or coherently interconnected material even if further improvements are made to the conductive material, such as providing slits in portions of the conductive material or implementing insulating materials within the conductive material.

[0059] Gas flow over the structural catalyst may be axial or coaxial with the current path through the structural catalyst, perpendicular to the current path, or have any other suitable direction relative to the current path.

[0060] The overall reaction scheme for converting CO2 to CO is endothermic. High temperatures, typically above 700-1000 °C, are required to reach good selectivity to CO.

[0061] In one example embodiment, the feed to the reverse water gas shift reaction is a substantially pure stream of H2 and CO2, with an H2 to CO2 ratio of 2 to 4. In another embodiment, the feed is a mixture of CO2, H2, and steam, with a CO2, H2 to steam ratio of 1:1:1. In another embodiment, the H2:CO2 ratio is 2.5 to 4, with a small amount of steam present in the feed such that H2O / CO2 = 0.05 to 0.2.

[0062] The term "conductivity" (electrical conductivity) refers to a temperature of 10 -5 ~10 -8 The term "electrically insulating" is meant to refer to a material having an electrical resistivity in the range of Ω·m. Thus, electrically conductive materials are, for example, metals such as copper, silver, aluminum, chromium, iron, nickel, or alloys of metals. Furthermore, the term "electrically insulating" refers to a material having an electrical resistivity of more than 10 Ω·m at 20°C, e.g., more than 10 Ω·m at 20°C. 9 ~10 25 This refers to materials in the Ω·m range.

[0063] When a reactor system includes an insulating layer between the structural catalyst and the pressure shell, adequate thermal and electrical insulation between the structural catalyst and the pressure shell is achieved. The presence of an insulating layer between the pressure shell and the structural catalyst can prevent excessive heating of the pressure shell and reduce heat loss to the surroundings. While the temperature of the structural catalyst can reach approximately 1300°C, at least in part, the use of an insulating layer between the structural catalyst and the pressure shell can keep the temperature of the pressure shell significantly lower, for example, at 500°C or 100°C, which is advantageous because typical construction steel materials are generally not suitable for pressure applications at temperatures above 1000°C. Furthermore, the insulating layer between the pressure shell and the structural catalyst helps control electrical current flow within the reactor system because the insulating layer is also electrically insulating. The insulating layer can be one or more layers of solid materials, such as ceramic, inert materials, fibrous materials, bricks, or gas barriers, or a combination thereof. Therefore, it is also conceivable that a purge gas or trapped gas could constitute or form part of the insulating layer.

[0064] Furthermore, the term "thermal insulating material" refers to a material with a thermal insulation capacity of approximately 10 W m -1 ·K -1 Note that this is meant to indicate materials with the following thermal conductivities: Examples of insulating materials are ceramics, brick, alumina-based materials, zirconia-based materials, and the like.

[0065] Advantageously, relevant gaps between the structural catalyst, the thermal insulation, the pressure shell, and / or other components within the reactor system are filled with an inert material, e.g., in the form of inert pellets. Examples of such gaps include the gap between the underside of the structural catalyst and the bottom of the pressure shell, and the gap between the side of the structural catalyst and the thermal insulation lining the pressure shell. The inert material may be, for example, a ceramic material in the form of pellets or tiles. The inert material assists in controlling gas distribution through the reactor system and in controlling gas flow through the structural catalyst. Additionally, the inert material typically provides thermal insulation.

[0066] In one embodiment of the reactor system of the present invention, the pressure shell suitably has a design pressure between 2 bar and 30 bar, preferably between 4 bar and 25 bar, more preferably between 6 bar and 20 bar, more preferably between 7 bar and 15 bar, and most preferably between 8 bar and 12 bar. At such pressure levels, it is possible to minimize the level of methane in the product stream exiting the second reaction zone of the structured catalyst. Because the hottest part of the reactor system is surrounded by a thermally insulating layer and electrically conductive material within the pressure shell of the reactor system, the temperature of the pressure shell can be kept significantly lower than the maximum process temperature. This allows for a relatively low design temperature of the pressure shell, for example, 500°C or 300°C, or preferably 200°C or 100°C, while still allowing for a maximum process temperature of 400°C or preferably 700°C, or even 1100°C or even 1300°C for the structured catalyst. Material strength is higher at the lower of these temperatures (corresponding to the design temperatures of the pressure shell shown above). This provides advantages when designing chemical reactors.

[0067] In another embodiment of the reactor system of the present invention, the pressure shell preferably has a design pressure of 30 to 200 bar. Alternatively, a design pressure of 30 to 200 bar may be selected to provide a product gas having a pressure compatible with the intended use of the product gas in downstream processes, such as as a feed gas for methanol synthesis. When used in methanol synthesis, the product gas pressure is preferably 70 to 100 bar, more preferably 75 to 95 bar. When used in a Fischer-Tropsch process, the product gas pressure is preferably 20 to 40 bar, more preferably 25 to 35 bar.

[0068] The resistivity of the conductive material is preferably 10 -5 Ω·m~10 -7 Resistivity in this range is between Ω·m. Materials with a resistivity in this range can efficiently heat the structure catalyst when energized with a power source. Graphite has a resistivity of about 10-5 Ω·m, Kanthal is approximately 10 at 20°C -6 Ω·m, and stainless steel is approximately 10 at 20°C. -7 Conductive materials have a resistivity of about 1.5·10 Ω·m at 20°C. -6 It can be made from an FeCr alloy with a resistivity of Ω·m.

[0069] Typically, the pressure shell has an inlet for admitting process gas and an outlet for discharging product gas, the inlet located near the first end of the pressure shell and the outlet located near the second end of the pressure shell, and the at least two conductors are both connected to the structural catalyst at a location closer to the inlet than the outlet. Because the inlet gas has a lower temperature than the product gas, the at least two conductors can be located in a substantially cooler portion of the reactor system, allowing the conductive material to cool at its most upstream portion due to heat consumed by the chemical reaction. The feedstock supplied through the inlet can cool the at least two conductors before being further heated by the heated structural catalyst along the gas path over the heated structural catalyst. To protect the connection between the conductors and the structural catalyst, it is advantageous to keep the temperature of all conductive elements except the conductive material low. When the temperature of the conductors and other conductive elements other than the conductive material is relatively low, there are fewer restrictions on the materials suitable for the conductors and other conductive elements other than the conductive material. Because the resistivity of the conductive elements increases as their temperature increases, it is desirable to avoid unnecessary heating of parts of the reactor system other than the conductive material. The term "conductive elements excluding conductive materials" is meant to refer to associated conductive elements arranged to connect a power source to the structural catalyst, excluding the conductive structural catalyst itself.

[0070] It should be noted that the systems of the present invention can include any suitable number of power sources and any suitable number of conductors connecting the power source(s) to the conductive material(s) of the structural catalyst.

[0071] Preferably, at least two conductors are routed through the pressure shell within a fitting such that the at least two conductors are electrically isolated from the pressure shell. The fitting may be, in part, plastic and / or ceramic material. The term "fitting" refers to a device capable of mechanically connecting two pieces of hardware in a pressure-tight configuration, thereby maintaining pressure within the pressure shell despite the at least two conductors being routed therethrough. Non-limiting examples of fittings may be an electrically insulating fitting, a dielectric fitting, a power compression seal, a compression fitting, or a flange. A pressure shell typically consists of side walls, end walls, flanges, and possibly additional components. The term "pressure shell" is meant to cover any of these components.

[0072] The pressure shell may further include one or more inlets adjacent to or associated with at least one of the fittings to allow cooling gas to flow over, around, near, or within at least one conductor within the pressure shell. This cools the conductor, thereby maintaining a low temperature experienced by the fitting. If cooling gas is not used, the conductor may be heated by the feedstock to the reactor system, resistive heating of the conductor due to applied current, and / or thermal conduction from the catalyst structure. The cooling gas may be, for example, hydrogen, argon, water, nitrogen, or a mixture thereof. The temperature of the cooling gas upon entering the pressure shell may be, for example, about 50°C, 200°C, or 250°C. In embodiments, the conductor(s) are hollow so that cooling gas can flow through the conductor(s) and cool them from the inside. Maintaining a low temperature of the fitting, for example, between 100 and 200°C, facilitates a leak-resistant configuration. Typically, a portion of the feedstock, such as one of the reactants, is supplied to the pressure shell as cooling gas. In another embodiment, a portion of the feedstock or a gas of the same composition as the feedstock is used as the cooling gas.

[0073] The reactor system may further include an inner tube in heat exchange relationship with the structure catalyst, the inner tube adapted to withdraw product gas from the structure catalyst such that product gas flowing through the inner tube or tubes is in heat exchange relationship with the gas flowing over the structure catalyst but is electrically isolated from the structure catalyst. This is a layout referred to herein as a bayonet reactor system. In this layout, product gas in the inner tube assists in heating the process gas flowing over the structure catalyst. Electrical isolation between the inner tube and the structure catalyst can be in the form of a gap or distance between the inner tube and the structure catalyst, or gas in the form of an inert material loaded around the inner tube and the structure catalyst. Gas can pass through the structure catalyst in an upflow or downflow direction.

[0074] The connection between the structural catalyst and the at least two conductors may be a mechanical connection, a welded connection, a brazed connection, or a combination thereof. The structural catalyst may include end portions physically and electrically connected to the structural catalyst to facilitate an electrical connection between the conductive material and the at least two conductors. The term "mechanical connection" is meant to refer to a connection in which two components are mechanically held together by a screw connection or clamp so that electrical current can flow between the components.

[0075] The conductive materials arranged in the array of conductive materials may be electrically connected to each other. The connection between two or more conductive materials may be by mechanical connection, clamping, soldering, welding, or any combination of these connection methods. Each conductive material may include an end portion to facilitate electrical connection. The two or more conductive materials may be connected to a power source in a series or parallel connection. The electrical connection between the two or more conductive materials is advantageously coherent and uniform along the connection surface between the two or more conductive materials, such that the two or more conductive materials act as a single, coherent or interconnected material; thereby promoting uniform electrical conductivity throughout the two or more conductive materials. Alternatively, or additionally, the structural catalyst may include an array of conductive materials that are not electrically connected to each other. Instead, the two or more electrically conductive materials are arranged together within the pressure shell but are not electrically connected to each other. In this case, the structural catalyst thus includes conductive materials connected in parallel to the power source.

[0076] Ceramic coatings, with or without catalytically active materials, can be applied directly to the metal surface of conductive materials by washcoating. Washcoating of metal surfaces is a well-known process, and its description is found, for example, in Cybulski, A., and Moulijn, JA, "Structured Catalysts and Reactors," Marcel Dekker, Inc., New York, 1998, Chapter 3, and in references therein. A ceramic coating may be applied to the surface of the conductive material, followed by the addition of catalytically active materials, or alternatively, a ceramic coating containing catalytically active materials may be applied to the macrostructure or conductive material. The ceramic coating may be, for example, an oxide containing Al, Zr, Mg, Ce, and / or Ca. Exemplary coatings are calcium aluminate or magnesium aluminum spinel. Such ceramic coatings may also contain additional elements such as La, Y, Ti, K, or combinations thereof. The ceramic coating is an electrically insulating material and will typically have a thickness of about 100 μm, for example in the range 10 to 500 μm.

[0077] Macrostructures can be extruded and sintered or 3D printed to give uniform, coherent shapes that can then be coated with a ceramic coating.

[0078] The conductive material and ceramic coating may be sintered in an oxidizing atmosphere to form a chemical bond between the ceramic coating and the conductive material, which results in particularly high thermal conductivity between the conductive material and the catalytically active material supported on the ceramic coating, thereby making the structured catalyst compact in terms of heat transfer to the catalytically active sites, and allowing reactor systems containing the structured catalyst to be compact and limited primarily by the rate of the chemical reaction.

[0079] In one embodiment, the structural catalyst has at least one electrically insulating element arranged to increase the current path between conductors to a length greater than the maximum dimension of the structural catalyst. Providing a current path between conductors greater than the maximum dimension of the structural catalyst may be achieved by providing an electrically insulating element(s) arranged between the conductors to prevent current from flowing through a portion of the structural catalyst. Such electrically insulating elements are arranged to increase the current path, and therefore increase the resistance through the structural catalyst. This may result in a current path through the structural catalyst that is, for example, greater than 50%, greater than 100%, greater than 200%, greater than 1000%, or greater than 10,000% longer than the maximum dimension of the structural catalyst.

[0080] Furthermore, such electrically insulating components are arranged to conduct current from one conductor closer to the first end of the catalyst than the second end toward the second end of the catalyst and back to a second conductor closer to the first end of the catalyst than the second end. Preferably, the current flows from the first end of the catalyst to the second end and back to the first end. As seen in the figures, the first end of the catalyst is its top end. The arrows labeled "z" in Figures 5-7 indicate the z-axis along the length of the catalyst. The dominant current path throughout the catalyst will have a positive or negative z-coordinate of the current density vector along the majority of the length of the current path. The dominant current path refers to the path of electrons through the catalyst's macrostructure that has the highest current density. It can also be understood as the path with the shortest length through the catalyst's macrostructure. Geometrically, the dominant current path can be quantified as the largest current density vector in a plane perpendicular to the gas flow direction in the coherent portion of the macrostructure. At the bottom of the structural catalyst, the current turns as shown, where the z coordinate of the associated current density vector is zero.

[0081] As used herein, the term coherent portion is meant to denote a cross-sectional area of ​​a macrostructure in which all walls of the coherent portion are geometrically connected to one or more other walls of the coherent portion in the same plane.

[0082] In an embodiment, the structural catalyst includes at least one electrically insulating component arranged to conduct current through the structural catalyst such that, along at least 70% of the length of the structural catalyst, the current density vector of the primary current path has a non-zero component parallel to the length of the structural catalyst. Thus, along at least 70% of the length of the structural catalyst, the current density vector has a positive or negative component parallel to the length of the structural catalyst. Thus, along at least 70%, e.g., 90% or 95% of the length of the structural catalyst, i.e., along the z-axis of the structural catalyst as seen in Figures 5 through 10, the current density vector of the primary current path has a positive or negative value along the z-axis. This means that current flows from the first end of the structural catalyst toward the second end, and then back toward the first end. Heat is absorbed from the structural catalyst due to the temperature of the gas entering the first end of the structural catalyst and the endothermic reverse water-gas shift reaction occurring above the structural catalyst. Thus, the first end of the catalyst remains cooler than the second end, and by ensuring that the current density vector of the main current path has a non-zero component parallel to the length of the catalyst, this is achieved with a substantially continuously increasing temperature profile, providing a controllable reaction front. In embodiments, the current density vector has a non-zero component parallel to the length of the catalyst for 70%, preferably 80%, more preferably 90%, and even more preferably 95% of the catalyst's length. Note that the term "catalyst length" is meant to refer to the catalyst's dimension in the direction of gas flow. In a catalyst as shown in the figures, the length is its longitudinal direction, i.e., its longest dimension. This is indicated in some figures by the arrow pointing to z.

[0083] Non-limiting examples of insulating portions are cuts, slits, or holes in the structure. Optionally, a solid insulating material such as ceramic can be used in the cuts or slits of the structure. If the solid insulating material is a porous ceramic material, catalytically active material can be advantageously incorporated into the pores, for example, by impregnation. The solid insulating material in the cuts or slits helps to separate the portions of the structure catalyst on the sides of the cut or slit from each other. As used herein, the term "maximum dimension of the structure catalyst" refers to the largest internal dimension of the geometric form taken up by the structure catalyst. If the structure catalyst is box-shaped, the largest dimension is the diagonal from one corner to the farthest corner, which may also be referred to as the spatial diagonal.

[0084] It should be noted that although the current through the structural catalyst may be arranged to twist or wind its way through the structural catalyst with electrically insulating components arranged to increase the current path, gases passing through the reactor system enter at one end of the reactor system and pass once over the structural catalyst before exiting the reactor system. To ensure that gases within the reactor system pass through the structural catalyst and the present catalytic material, inert material is advantageously present in the relevant gaps between the structural catalyst and the rest of the reactor system.

[0085] The length of the gas path through the structured catalyst is preferably less than the length of the electrical current path from one electrode through the structured catalyst to the next. The ratio of the gas path length to the electrical current path length may be less than 0.6, or less than 0.3, or less than 0.1, or even less than 0.002. The gas path length is defined as the distance from the inlet for the feedstock, through the structured catalyst, to the outlet for the product gas.

[0086] Typically, structural catalysts have electrically insulating components arranged such that the current path through the structural catalyst is a zigzag path. Here, the terms "zigzag path" and "zigzag route" are meant to refer to a path with variable angle corners that traces a path from one conductor to another. A zigzag path, for example, is a path that goes upward, turns, and then goes downward. A zigzag path may require only one turn, or it may have multiple turns, upward, and then downward through the structural catalyst.

[0087] It should be noted that insulating components placed to increase the current path do not necessarily refer to ceramic coatings on conductive materials, which are also considered electrically insulating but do not change the length of the current path between conductors connected to the conductive material.

[0088] The macrostructure can have multiple parallel channels, multiple non-parallel channels, and / or multiple labyrinthine channels, each with a channel defining a wall. Several different macrostructure configurations can be used, so long as the surface area of ​​the structured catalyst exposed to the gas is as large as possible. In a preferred embodiment, the macrostructure has parallel channels, since such parallel channels provide a structured catalyst with very low pressure loss. In a preferred embodiment, the parallel longitudinal channels are distorted along the length of the macrostructure. In this way, gas molecules flowing through the macrostructure tend to mostly collide with the walls within the channel, rather than simply flowing linearly through the channel without contacting the walls. The channel dimensions must be appropriate to provide a macrostructure with sufficient resistivity. For example, the channels can be quadratic (as viewed in a cross section perpendicular to the channels) and have square side lengths between 1 and 3 mm, although channels with a maximum cross-sectional area of ​​up to about 4 cm are contemplated. The walls may have a thickness of, for example, 0.2 to 2 mm, e.g., about 0.5 mm, and the ceramic coating supported by the walls has a thickness of 10 μm to 500 μm, e.g., 50 μm to 200 μm, e.g., 100 μm. In another embodiment, the macrostructure of the structural catalyst is cross-corrugated.

[0089] In general, when the macrostructures are extruded or 3D printed, the pressure drop from the inlet to the outlet of the reactor system can be significantly reduced compared to reactors where the catalyst material is in the form of pellets.

[0090] Preferably, the reactor system further comprises a bed of a second catalytic material upstream of the structural catalyst within the pressure shell. Here, the term "upstream" refers to the direction of feed flow. Therefore, the term "upstream" here means that the feed is directed through a bed of the second catalytic material before reaching the structural catalyst. This provides a situation in which the second catalytic material can be deployed to precondition the feed flow. The bed of the second catalytic material does not require specific heating; however, if the bed of the second catalytic material is in close proximity to the structural catalyst, it can be indirectly heated. For clarity of terminology used herein, please note that the term "structural catalyst" may also be referred to as "first catalytic material" to distinguish it from the second, third, and / or fourth catalytic materials. In one embodiment, the second catalytic material is in the form of particles comprising a support material coated with a catalytically active material capable of catalyzing both the reverse water gas shift reaction and the methanation reaction. In one embodiment, the catalytic activity of the second catalytic material is sufficient to drive the methanation reaction to equilibrium. In this situation, no further methanation occurs in the structural catalyst; rather, a reverse methanation reaction occurs throughout the structural catalyst, i.e., the reaction occurring throughout the structural catalyst is endothermic. In the context of the present invention, the phrase "a methanation reaction occurs" in relation to the structural catalyst means that during the passage of gas from the first end to the second end of the structural catalyst, the methanation reaction proceeds in both the forward and reverse directions, or, even in the case of the embodiments discussed in this paragraph, only in the reverse direction. In this particular embodiment, the first exothermic reaction zone is located inside the bed of the second catalytic material. In an alternative embodiment, the second catalyst is in the form of an unheated structural catalyst.

[0091] In embodiments, the first catalytic material has different sections of active material, i.e., the most upstream portion of the catalytic material has a predominant reactivity for one type of reaction, and a second portion has a different reactivity. Specifically, the relative activity for methanation and reverse water gas shift reactions can vary along the first catalytic material.

[0092] The reactor system may further include a third catalyst material in the form of catalyst pellets, extrudates, or granules loaded into the channels of the macrostructure. In this embodiment, the reactor system thus has a catalytically active material in the coating of the macrostructure and a third catalyst material in the form of catalyst pellets, extrudates, or granules within the channels of the macrostructure. The pellets may be prepared with dimensions that loosely match the size of the channels, for example, to form a single row of pellets stacked one on top of the other within the channels of the macrostructure. Alternatively, the pellets, extrudates, or granules may be prepared with dimensions significantly smaller than the size of the channels to form a packed bed within each channel. As used herein, the term "pellet" is intended to refer to any distinct structure having a maximum outer dimension in the millimeter or centimeter range, while "extrudate" and "granule" are intended to define catalyst materials having a maximum outer dimension defined within a certain range.

[0093] A bed of a fourth catalytic material may be disposed within the pressure shell and downstream of the structural catalyst. Such fourth catalytic material may be in the form of catalyst pellets, extrudates, or granules.

[0094] Thus, the first, second, third, and fourth catalytic materials may be catalytic materials suitable for methanation and reverse water gas shift reactions. In an embodiment, the second, third, and fourth catalytic materials may be Ni / MgAl2O3. Other possible catalytic materials include noble metals, including Ru, Rh, and Ir, and typical support materials known in the art, such as calcium aluminate. In configurations where a combination of the second, third, and fourth catalytic materials is included in the reactor system, the catalysts of each catalytic material may be different.

[0095] The geometric surface area of ​​the macrostructure is between 100 and 3000 m 2 / m 3 , e.g., 500-1100m 2 / m 3Typically, the material of the macrostructure can be heated to 500 W / m by resistive heating of the material. 2 ~100,000W / m 2 , preferably 500 W / m 2 ~50,000W / m 2 Preferably, the material is selected to be arranged to provide a heat flux of 5 kW / m across the geometric surface by resistive heating of the material. 2 More than 12kW / m 2 Below, for example, 8kW / m 2 More than 10kW / m 2 The following heat flux is provided: Heat flux is given as heat per geometric surface area of ​​the surface exposed to the gas.

[0096] In one embodiment, the structural catalyst comprises a first portion configured to generate a first heat flux and a second portion configured to generate a second heat flux, the first heat flux being lower than the second heat flux, and the first portion is upstream of the second portion. Here, the term "the first portion is upstream of the second portion" is intended to indicate that gas supplied to the reactor system reaches the first portion before reaching the second portion. The first and second portions of the structural catalyst may be two different macrostructures supporting a ceramic coating that supports catalytically active material, and the two different macrostructures may be arranged to generate different heat fluxes for a given current and voltage. For example, the first portion of the structural catalyst may have a large surface area, while the second portion of the structural catalyst may have a smaller surface area. This can be achieved by providing the second portion of the structural catalyst with a structural catalyst having a cross-sectional area smaller than that of the first portion. Alternatively, the current path through the first portion of the catalyst may be more direct than the current path through the second portion of the catalyst, causing the current to twist and turn more through the second portion than through the first portion, thereby generating more heat in the second portion of the catalyst than in the first portion. As previously mentioned, slits or cuts in the macrostructure may cause the current path to zigzag through the macrostructure. It should be noted that the first and second portions of the catalyst may receive different currents and voltages to provide different heat fluxes. However, different heat fluxes in the first and second portions may also be achieved by providing the same current and voltage through / on the first and second portions due to the different physical properties of the first and second portions, as shown above. In a further embodiment, the structural catalyst comprises a third portion positioned to generate a third heat flux, the third heat flux being lower than the first and / or second heat fluxes, the third portion being downstream of the first and / or second portions.

[0097] In one embodiment of the reactor system of the present invention, the catalytically active material is provided in a zone disposed closest to the second end of the catalyst structure, spanning 10-100%, preferably 30-100%, and more preferably 50-100% of the length of the catalyst structure from the first end to the second end. The predetermined temperature range for the gas exiting the pressure shell / reactor system is 500-1300°C. The product gas outlet temperature from the catalyst structure is measured directly below or at the most downstream surface of the catalyst structure. Measurement techniques include thermocouples (by voltage drop), resistance temperature detectors, or infrared detection. The measurement point can be separate from the catalyst structure and embedded in the downstream inert gas / catalyst, or directly on a surface with an insulating surface coating.

[0098] The structure catalyst in the reactor system is preferably one in which the ratio of the area equivalent diameter of a horizontal cross section passing through the structure catalyst to the height of the structure catalyst is in the range of 0.1 to 2.0. The area equivalent diameter of a cross section passing through the reactor system is defined as the diameter of a circle having an area equivalent to the area of ​​the cross section. When the ratio of the area equivalent diameter to the height of the structure catalyst is 0.1 to 2.0, the pressure shell containing the structure catalyst can be relatively small compared to reactor systems for other endothermic reactions, such as current tubular reformers for steam methane reforming.

[0099] Typically, as gas flows through a reactor system in either an upflow or downflow direction, the gas flows through channels within the structured catalyst along its height. When the structured catalyst includes a number of arrays or arrays of macrostructures, the individual macrostructures within the array may be arranged side-by-side, on top of each other, or a combination thereof. When the structured catalyst includes two or more macrostructures, it is emphasized that the dimensions of the structured catalyst are the dimensions of the two or more macrostructures. Thus, as an example, if the structured catalyst is composed of two macrostructures, each with a height h, placed on top of each other, the height of the structured catalyst is 2h.

[0100] The volume of the structure catalyst is selected taking into consideration the desired feed conversion and / or temperature from the reactor system, which correlates to the heating value of the conductive material.

[0101] Preferably, the reactor system has a height of 0.5 to 7 m, more preferably 0.5 to 3 m. Exemplary values ​​for the reactor system height are less than 5 m, preferably less than 2 m, and even less than 1 m. The dimensions of the reactor system and the dimensions of the structural catalyst within the reactor system are interrelated. Of course, the pressure shell and insulating layers make the reactor system somewhat larger than the structural catalyst itself.

[0102] In one embodiment, the first product gas contains methane, such as at least 0.5% by volume or at least 1.0% by volume, hi other embodiments, the product gas contains at most 5% by volume or preferably less than 3% by volume of methane.

[0103] In one embodiment, the H2 / CO ratio of the product gas is between 1.5 and 5.0, for example, between 2.0 and 3.0.

[0104] In one embodiment, the product gas is cooled in a waste heat boiler where cooling is achieved by evaporation of water to steam. This steam can be used as a means to produce electricity in a turbine. Alternatively, the steam can be used to produce hydrogen by electrolysis, such as solid oxide electrolysis.

[0105] The reactor system may further include an upgrading unit positioned to receive the product gas and separate it into an upgraded synthesis gas stream and an off-gas stream.

[0106] The present invention further relates to a method for converting a feedstock comprising CO and H2 to a first product gas comprising CO, the method comprising a reactor system including a pressure shell containing a structural catalyst comprising a macrostructure of an electrically conductive material and a catalytically active material; the reactor system including thermal insulation between the structural catalyst and the pressure shell; the method comprising the steps of: - providing a pressurized feedstock; - feeding the pressurized feedstock into the pressure shell through an inlet positioned at a first end of the structural catalyst such that the feedstock enters the structural catalyst; -using a catalytically active material capable of catalyzing both the reverse water gas shift reaction and the methanation reaction; - subjecting the feedstock to a reverse water gas shift reaction over the structured catalyst at a temperature and pressure such that both the reverse water gas shift reaction and the methanation reaction occur; - discharging a product gas from the pressure shell, wherein the product gas exits the structural catalyst at a second end of the structural catalyst; - providing electrical power through electrical conductors connecting a power source located outside the pressure shell to the structural catalyst, allowing electrical current to flow through the macrostructure, thereby heating at least a portion of the structural catalyst to a temperature of at least 500°C, the at least two conductors being connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than the second end of the structural catalyst, and the structural catalyst being configured to pass electrical current from one conductor substantially to the second end of the structural catalyst and back to a second conductor of the at least two conductors, thereby heating at least a portion of the structural catalyst to a temperature sufficient for the feedstock to undergo a reverse water gas shift reaction on the structural catalyst; Discharging a first product gas comprising CO from the reactor system.

[0107] All details of the above system relate, where possible, to the above method.

[0108] In an embodiment of the method of the present invention, the structural catalyst has a first reaction zone located closest to a first end of the structural catalyst, the first reaction zone having an overall exothermic reaction, and a second reaction zone located closest to a second end of the structural catalyst, the second reaction zone having an overall endothermic reaction. Preferably, the first reaction zone extends over 5% to 60% of the length of the structural catalyst from its first end to its second end.

[0109] In an embodiment of the method of the present invention, the concentration of methane is higher in the partially catalyzed feedstock within at least a portion of the structured catalyst than in the feedstock and the first product gas.

[0110] In an embodiment of the method of the present invention, the temperature of the structural catalyst increases continuously from the first end to the second end of the structural catalyst.

[0111] In one embodiment, the feedstock is pressurized to a pressure of between 2 and 30 bar. The feedstock may be pressurized to a pressure of between 30 and 200 bar. Suitably, at least a portion of the structured catalyst is heated to a temperature of at least 500°C, preferably at least 700°C. The maximum temperature to which the structured catalyst is heated is about 1400°C.

[0112] In one aspect of the method, the method further includes flowing a cooling gas through an inlet through the pressure shell so that the cooling gas flows over at least one conductor.

[0113] The method can further include feeding the first product gas comprising CO to an upgrading unit and separating it into an upgraded gas stream and an off-gas stream. The upgrading unit can be configured such that the off-gas stream is compressed, recycled, and mixed with the supplied feedstock before passing over the structured catalyst.

[0114] The upgrading unit may consist of a flash separation unit, a pressure swing adsorption (PSA) unit, a temperature swing adsorption (TSA) unit, a membrane unit, CO2 separation or a combination of CO2 separation and a cold box. A cold box is defined as a low temperature process for separating a mixture of H2, CO, and other gases into a somewhat pure CO stream, a somewhat pure H2 stream, and the balance remaining from the feed stream.

[0115] Flash separation refers to a phase separation device that separates a stream into liquid and gas phases according to thermodynamic phase equilibrium at a certain temperature.

[0116] CO2 separation refers to equipment that uses processes such as chemical absorption to remobilize CO2 from process gases. In chemical absorption, CO2-containing gas is passed over a solvent that reacts with CO2 to bind it. Most chemical solvents are amines, classified as primary amines, e.g., monoethanolamine (MEA) and diglycolamine (DGA), secondary amines, e.g., diethanolamine (DEA) and diiso-propanolamine (DIPA), and tertiary amines, e.g., triethanolamine (TEA) and methyldiethanolamine (MDEA). Ammonia and liquid alkali carbonates such as K2CO3 and NaCO3 can also be used.

[0117] Swing adsorption refers to devices that separate the adsorption of heavy gases (e.g., CO2) from light gases (e.g., H2). In this type of device, a dynamic equilibrium is established between the adsorption and desorption of the heavy gas on the adsorbent material. Adsorption can occur through steric, kinetic, or equilibrium effects. The exact mechanism depends on the adsorbent used, and the equilibrium saturation depends on temperature and pressure. Typically, the adsorbent is treated to near saturation in the process gas and then needs to be regenerated. This can be achieved by changing the pressure or temperature. In practice, a two-reactor process is used, where the adsorbent is first saturated in one reactor at high pressure or low temperature, and then the reactors are switched and the heavy gas is desorbed from the same reactor at a lower pressure or higher temperature.

[0118] Membrane refers to separation across an at least partially solid barrier, such as a polymer, where the transport of individual gas species occurs at different rates determined by their permeabilities, which can enrich or dilute the components in the remainder of the membrane.

[0119] Cryogenic separation refers to the process of separating individual components from a gas mixture by utilizing the phase changes of different species in the gas and controlling the temperature.

[0120] In an embodiment of the process of the present invention, the feedstock CO2 and H2 are subjected to a first compression step before feeding the pressurized feedstock to the pressure shell, and then the first product gas is subjected to a second compression step before discharging the first product gas from the reactor system. Preferably, in the first compression step, the feedstock CO2 and H2 are pressurized to a pressure between 2 and 30 bar. In one embodiment, the feedstock CO2 and H2 can be pressurized as separate streams and mixed to form the feedstock, which is then fed to the pressure shell. In another embodiment, the feedstock CO2 and H2 are mixed and pressurized as a mixed stream to form the pressurized feedstock, which is then fed to the pressure shell.

[0121] If the first product gas is intended for use in a downstream process, this process will typically have a CO2-containing product gas pressure requirement of 20-95 barg for use as a feed gas for methanol synthesis, and 20-40 barg for use as a feed for a Fischer-Tropsch process. In this situation, according to a preferred embodiment of the inventive process, it is preferable to compress the feedstock only to the lowest pressure level necessary to efficiently equip the inventive process, and then compress the first product gas to the pressure level required for the downstream process. In one embodiment, the pressure after the first compression step is 5-15 barg, and compression after the second compression step is tailored to the downstream process. Maintaining a relatively low pressure in the inventive process has the advantage that thermodynamic equilibrium limits the effective formation of methane. Second, by condensing the water vapor formed by the reverse water-gas shift reaction and methanation reaction, the amount of gas molecules can be effectively reduced downstream of the inventive reactor system, thereby reducing the need for compression in this layout. This feature allows for a lower total energy usage for the first and second compression steps compared to having only a first compression step, although the first step compression should always be great enough to compensate for pressure losses in the equipment and piping used to facilitate the process of the present invention.

[0122] Thus, there is provided a method for rapidly switching the reverse water gas shift reaction of a feedstock comprising CO and H from a first steady-state reaction condition (A) to a second steady-state reaction condition (B), or vice versa, in a reactor system as defined herein.

[0123] Reaching steady state is defined as when a central process parameter (feed flow rate, outlet temperature, reactant conversion, etc.) reaches a value that is within ±15% of the average process value of the given process parameter for the subsequent time period.

[0124] Conditions A or B of the present invention are a method for treating a feedstock containing CO2 and H2 and either water, carbon oxides, nitrogen, or argon at a flow rate of 300 Nm 3 / h~100,000Nm 3 This includes heating the catalyst in a system where the product gas outlet temperature from the structural catalyst is heated by electrical power balance to a temperature of 500 to 1300°C at a total flow rate of 1 / h and a pressure of 5 barg to 150 barg. As the feedstock passes through the monolith, it reacts towards reaction equilibrium.

[0125] The term "reverse" is used herein to refer to the case of switching from a first reaction condition (A) to a second reaction condition (B), as well as the case of switching from a second reaction condition (B) to a first reaction condition (A). It is noteworthy that the switch from condition A to B is considered complete when the process value of the system reaches within 85% of the steady-state condition.

[0126] A reactor system as described above, comprising a pressure shell containing a structural catalyst arranged to catalyze the reaction of a feedstock comprising CO2 and H2, said structural catalyst comprising a macrostructure of electrically conductive material, said macrostructure capable of supporting a ceramic coating, said ceramic coating capable of supporting a catalytically active material, said reactor system being provided with thermal insulation between said structural catalyst and said pressure shell. All details provided above in relation to reactor systems are relevant to the present technology.

[0127] The method of this aspect of the invention comprises the following steps. Under the first steady-state reaction condition (A), - feeding the feedstock into the reactor system at a first total flow rate; and - providing a first electrical power through an electrical conductor connecting a power source located outside the pressure shell to the structural catalyst, thereby causing a first electrical current to flow through the electrically conductive material; whereby at least a portion of the structural catalyst is heated to a first temperature at which the feedstock is converted over the structural catalyst under the first steady-state reaction conditions (A) into a first product gas mixture; and discharging the first product gas from the reactor system; Then, under the second steady-state reaction conditions (B), - feeding the feedstock into the reactor system at a second total flow rate; and - providing a second electrical power through an electrical conductor connecting a power source located outside the pressure shell to the structural catalyst, thereby causing a second electrical current to flow through the electrically conductive material; thereby heating at least a portion of the structural catalyst to a second temperature; at which temperature the feedstock is converted over the structural catalyst under the second steady-state reaction conditions (B) into a second product gas mixture; and discharging the second product gas from the reactor system.

[0128] To achieve the first and second steady-state reaction conditions (A) and (B), the second power is greater than the first power; and / or the second total flow rate is greater than the first total flow rate.

[0129] It is worth noting that as the total flow rate increases, the input of cooling feedstock increases, causing the catalyst to cool and the reactivity to decrease so that the second steady-state reaction condition (B) is achieved. Large changes in flow rate will change the energy required for the process.

[0130] A change in total flow rate may include a change in total flow rate without a change in composition, or a change in composition such as increasing the recycle rate or changing some of the feedstock.

[0131] In one embodiment, the ratio (A:B) of the total gas supply flow rates under the first reaction condition A and the second reaction condition B is at least 1:10. Switching between condition A and condition B can result in a significant increase / decrease in the amount of product gas produced. This is advantageous when the present invention is used for energy storage, for example, when excess electrical energy from the energy grid is available and can thus be stored as chemical energy, or vice versa, to increase the availability of electrical energy in the grid when electrical energy is needed elsewhere. Furthermore, this embodiment allows the present invention to be used to supply large amounts of product gas for periods when downstream processes require it, while otherwise operating in a standby mode. This is advantageous when there is no continuous demand for product gas.

[0132] In another embodiment, the product gas outlet temperature from the structure catalyst under reaction condition B is 50°C to 800°C higher, for example 100°C to 500°C higher, preferably 150°C to 400°C higher, than the product gas outlet temperature from the structure catalyst under reaction condition A. This allows the reactor system to be quickly brought up to operating conditions from a low temperature state. This is advantageous in the context of system startup, The start-up procedure includes steps including: heating the heated process equipment in a non-condensable gas to a temperature above the condensation point of the plant's steady-state conditions at full operation; pressurizing the feed components; supplying the feedstock components to the reactor system while applying a first power; The second power-on step switches to a higher operating temperature. In this way, all steps of the start-up procedure occur relatively quickly.

[0133] The product gas outlet temperature from the structure catalyst under reaction condition B is typically no more than 50° C. higher than the product gas outlet temperature from the structure catalyst under reaction condition A (typically no more than 50° C. higher than the product gas outlet temperature). This allows for rapid changes between conditions A and B without significantly changing the product gas composition from the system. In this way, product gas demands for downstream processes in the reactor system can be easily supplied in different amounts without significantly interfering with their chemical environments.

[0134] In one embodiment, switching between reaction conditions A and B involves gradually changing the total gas supply flow rate from the first total flow rate to the second total flow rate and simultaneously gradually changing the applied potential across the conductive material from the first power to the second power. In this manner, the product gas composition can be maintained substantially constant during the transition phase. In one embodiment, the stepwise change is performed in a manner that increases the flow rate in small increments while increasing the power in order to maintain a substantially constant product gas outlet temperature from the structure catalyst.

[0135] In an embodiment, the reactor system further comprises a control system arranged to control the power supply to ensure that the temperature of the gas exiting the pressure shell is within a predetermined range and / or to ensure that the conversion of the feedstock is within a predetermined range. Control of the power supply is control of the electrical output from the power supply. Control of the power supply can be implemented, for example, as control of the voltage and / or current from the power supply, as control of whether the power supply is turned on or off, or a combination thereof. The power supplied to the structural catalyst can be in the form of alternating current or direct current.

[0136] According to one embodiment, a proportional-integral-derivative (PID) controller controls the electrical potential based on a feedback reading of a process value of the product gas outlet temperature from the structure catalyst.

[0137] The methods described herein allow for rapid switching between conditions A and B. Suitably, therefore, switching between reaction conditions A and B is carried out over a period of less than 3 hours, such as less than 2 hours, for example less than 60 minutes, preferably less than 30 minutes, more preferably less than 15 minutes.

[0138] In one embodiment, switching between reaction conditions A and B includes providing a second power to the structure catalyst, preferably while keeping the total flow rate essentially constant.

[0139] In one embodiment, the switching between reaction conditions A and B includes a transition state between the reaction conditions A and B, the transition state including a first period during which power is turned off, followed by a second period during which the structure catalyst is supplied with the second power of condition B. This allows for a faster establishment of a steady state.

[0140] In one embodiment, the switching between the reaction conditions A and B includes a transition state between the reaction conditions A and B; the transition state includes a first period during which the structure catalyst is supplied with a third power, followed by a second period during which the structure catalyst is supplied with a second power of the condition B, the third power being greater than the second power, thereby allowing a steady state to be established more quickly.

[0141] The method may include further steps performed on the hydrogen-containing product gas, such as purification, pressurization, heating, cooling, etc., to provide a final product gas for application downstream of the reactor system of the invention.

[0142] Additionally, it should be noted that the order in which the steps of the method are presented is not necessarily the order in which the steps of the method are performed, in that two or more steps may be performed simultaneously, or the order may differ from that presented above.

[0143] In an embodiment, the method includes pressurizing the feedstock upstream of the pressure shell to a pressure of at least 2 bar. The selected operating pressure is defined by the integration of the reactor with the endothermic reaction and surrounding process steps. In a preferred embodiment, pressurization of the feedstock is achieved using pumps for liquid components of the feedstock, such as water, and compressors for gaseous components, such as carbon dioxide and hydrogen. Downstream of the pressurization device, a mixer and / or preheater can be included to provide the desired reaction mixture and reactor system inlet temperature.

[0144] In an embodiment of the process according to the invention, the temperature of the feed gas entering the reactor system is between 100°C and 400°C.

[0145] In an embodiment of the method of the present invention, the structural catalyst is heated so that the maximum temperature of the structural catalyst is between 500°C and 1300°C. The temperature used will depend on the endothermic reaction. The maximum temperature of the structural catalyst depends on the material of the conductive material; thus, for an FeCr alloy, which melts at a temperature of 1380°C to 1490°C (depending on the actual alloy), the maximum temperature should be slightly lower than the melting point, as the material becomes soft and ductile as it approaches the melting point, such as about 1300°C if the melting point of the conductive material is about 1400°C. The maximum temperature may also be limited by the durability of the catalyst material, coating, and catalytically active materials.

[0146] In an embodiment, the method according to the invention further comprises the step of injecting a cooling gas from an inlet through the pressure shell to allow the cooling gas to flow over the at least one conductor and / or fitting. The cooling gas may advantageously be hydrogen, nitrogen, carbon dioxide, or any other gas suitable for cooling an area or zone around the at least one conductor. A portion of the feedstock may be fed to the pressure shell as the cooling gas.

[0147] In embodiments according to the invention, the method further includes injecting a cooling gas from an inlet through the pressure shell so that the cooling gas flows over at least one conductor and / or fitting. The cooling gas may be any suitable gas; examples of such gases are hydrogen, nitrogen, methanol, methane, or mixtures thereof. The cooling gas may flow through the conductor(s) and cool it(s) from within; in this case, the conductor(s) must be hollow to accommodate the cooling gas flowing through / among them.

[0148] The catalytic material for the reaction can be Ni / Al2O3, Ni / ZrO2, Ni / MgAl2O3, Ni / CaAl2O3, Ru / MgAl2O3, or Rh / MgAl2O3. The catalytically active material can be Fe, Ga, Ni, Ru, Rh, Ir, or a combination thereof, and the ceramic coating can be mixed with Al2O3, ZrO2, MgAl2O3, CaAl2O3, or a combination thereof, and potentially with oxides of Y, Ti, La, or Ce. The maximum temperature of the reactor can be between 500 and 1300°C. The feed pressure can be between 2 and 180 bar, preferably about 10 bar or alternatively 25 bar. In one embodiment, the macrostructure consists of an alloy of FeCrAl, supporting a ceramic coating of a ZrO2 and MgAl2O4 mixture, with Ni as the catalytically active material.

[0149] In a preferred embodiment, the reactor comprises a second catalytic material of Ni / MgAl2O4, a first catalytic material whose macrostructure is made of an alloy of FeCrAl supporting a ceramic coating of ZrO2, Ni being the catalytically active material, and a third catalytic material of Ni / CaAl2O4.

[0150] In the drawings, like reference numbers refer to like elements.

[0151] FIG. 1a is a cross-sectional view through one embodiment of a reactor system 100 according to the present invention. The reactor system 100 comprises a structural catalyst 10 arranged as an array of macrostructures 5. Each macrostructure 5 in the array is coated with a ceramic coating impregnated with a catalytically active material. The reactor system 100 further includes conductors 40, 40′ connected to a power source (not shown) and to the structural catalyst 10, i.e., the array of macrostructures. The conductors 40, 40′ are routed through the wall of the pressure shell 20 containing the structural catalyst, through insulating material 30 inside the pressure shell, and through fittings 50. The conductors 40′ are connected to the array of macrostructures 5 by conductor contact rails 41.

[0152] In one embodiment, the power supply provides a voltage of 26 V and a current of 1200 A. In another embodiment, the power supply provides a voltage of 5 V and a current of 240 A. The current is conducted to the conductor contact rails 41 via electrical conductors 40, 40', and the current flows within the structural catalyst 10 from one conductor contact rail 41, e.g., the conductor contact rail seen on the left side in FIG. 1a, to the other conductor contact rail 41, e.g., the conductor contact rail seen on the right side in FIG. 1a. The current can be an alternating current, e.g., flowing alternately in both directions, or a direct current, flowing in either of two directions.

[0153] The macrostructure 5 is made of an electrically conductive material. Kanthal, an alloy of aluminum, iron, and chromium, is particularly preferred. The ceramic coating, e.g., oxide, applied to the structural catalyst 5 is impregnated with a catalytically active substance. The conductors 40, 40' are made of materials such as iron, aluminum, nickel, copper, or alloys thereof.

[0154] In operation, a feedstock containing CO and H enters the reactor system 100 at the top, as indicated by arrow 11. A product gas containing CO exits the reactor system at the bottom, as indicated by arrow 12.

[0155] FIG. 1b shows the reactor system 100 of FIG. 1a with a portion of the pressure shell 20 and the layer of insulating material 30 removed, and FIG. 2 shows an enlarged view of a portion of the reactor system 100. In FIGS. 1b and 2, the connection between the conductor 40' and the conductor contact rail 41 is more clearly shown than in FIG. 1a. Additionally, it can be seen that the conductor 40 is routed through the pressure shell wall with fittings 50, splitting the single conductor 40 into three conductors 40' within the pressure shell. Note that the number of conductors 40' may be any suitable number, such as less than or greater than three.

[0156] In the reactor system shown in FIGS. 1a, 1b, and 2, conductors 40, 40' are routed through the wall of the pressure shell 20 containing the structural catalyst, through the insulating material 30 inside the pressure shell, and via fitting 50. The reverse water-gas shift reaction feedstock enters the reactor system 100 through an inlet on the upper side of the reactor system 100, as indicated by arrow 11, and the converted product gas exits the reactor system 100 through an outlet on the lower side of the reactor system 100, as indicated by arrow 12. Additionally, one or more additional inlets (not shown in FIGS. 1a-2) are advantageously present near or in conjunction with fitting 50. Such additional inlets allow cooling gas to flow over, around, near, or within at least one conductor within the pressure shell to reduce heating of the fitting. The cooling gas can be, for example, hydrogen, nitrogen, methane, or a mixture thereof. The temperature of the cooling gas upon entry into the pressure shell can be, for example, approximately 100°C.

[0157] In the reactor system 100 shown in FIGS. 1a-2, an inert material (not shown in FIGS. 1a-2) is advantageously present between the underside of the structural catalyst 10 and the bottom of the pressure shell. Additionally, the inert material is advantageously present between the outer side of the structural catalyst 10 of the macrostructure 5 and the insulating material 30. Thus, one side of the insulating material 30 faces the inside of the pressure shell 20, and the other side of the insulating material 30 faces the inert material. The inert material may be, for example, a ceramic material and may be in the form of pellets. The inert material controls pressure drop across the reactor system 100 and helps control gas flow through the reactor system 100, thereby forcing gas to flow over the surface of the structural catalyst 10.

[0158] 3a and 3b are cross-sectional schematic diagrams of one embodiment of a reactor system 100', 100" of the present invention including a structural catalyst 10'. The structural catalyst 10' may be comprised of a single macrostructure having a ceramic coating supporting catalytically active material, or may include two or more macrostructures. Each reactor system 100', 100" includes a pressure shell 20 and an insulating layer 80 between the structural catalyst 10' and the pressure shell 20. An inert material 90 can be used to fill the gap between the structural catalyst 10' and the insulating layer or pressure shell 20. In FIGS. 3a and 3b, the inert material 90 is shown as a dotted area. The inert material 90 can be in any suitable form, such as inert pellets, made of a ceramic material, for example. The inert material 90 helps control the pressure drop through the reactor system and control the flow of gas through the reactor system. Additionally, the inert material typically has a thermal insulating effect.

[0159] 3a and 3b, it can be seen that the reactor system 100', 100'' further includes an inner tube 15 in heat exchange relationship with the structural catalyst 10'. The inner tube 15 is adapted to draw product gas from the structural catalyst 10' such that the product gas flowing through the inner tube or tubes is in heat exchange relationship with the gas flowing over the structural catalyst, while the inner tube 15 is electrically insulated from the structural catalyst 10' by either an insulating layer 80, an inert material 90, a gap, or a combination. This is a layout referred to as a bayonet reactor system. In this layout, the product gas in the inner tube assists in heating the process gas flowing over the macrostructure. In the layout shown in FIGS. 3a and 3b, the feedstock enters the reactor system 100', 100'' as indicated by arrow 11 and subsequently enters the structural catalyst 10' as indicated by arrow 13. While the feedstock passes over the structural catalyst 10', it undergoes a reverse water-gas shift reaction. Gas exiting the structural catalyst 10' is at least partially converted to CO. At least partially converted gas flows from the structural catalyst 10' into the inner tube 15 as shown by arrow 14 and out of the inner tube as shown by arrow 12. Even with the presence of an insulating layer 80 between the inner tube 15 and the structural catalyst 10', some heat transfer will occur between the gas in the inner tube 15 and the gas in or upstream of the structural catalyst 10'. In the embodiment shown in Figures 3a and 3b, the feedstock flows down the structural catalyst 10' and up the inner tube 15; however, an inverted configuration is also contemplated, with the feedstock flowing up the structural catalyst 10' and down the inner tube 15.

[0160] 4 and 5 show an embodiment of a structural catalyst including an array of macrostructures viewed from above and a side view, respectively. FIG. 4 shows a structural catalyst 10 including an array of macrostructures 5 viewed from above, i.e., from arrow 11 in FIGS. 1a and 1b. The array has six rows of five macrostructures 5, i.e., 1a, 1b, 1c, 1d, 1e, and 1f. Each row of macrostructures 5 is connected to its adjacent macrostructures in the same row, with the outermost two macrostructures in each row connected to conductor contact rails 41. Adjacent macrostructures 5 in a row of macrostructures are connected to each other by connecting pieces 3.

[0161] FIG. 5 is a side view of the structural catalyst 10 having a row of macrostructures 5 of FIG. 4. It can be seen from FIG. 5 that each macrostructure 5 extends longitudinally, perpendicular to the cross-section seen in FIG. 4. Each macrostructure 5 has a slit 60 cut along its length (see FIG. 5). Thus, when energized by a power source, current enters the array of macrostructures 5 via the conductor contact rail 41, is conducted downward through the first macrostructure 5 to the lower limit of the slit 60, and then is conducted upward toward the connecting piece 3. The current is conducted downward and upward through each macrostructure 5 of each row 1a-1f of macrostructures 5 in the array 10 via a corresponding zigzag path. This configuration advantageously increases the resistance (resistance) of the structural catalyst 10.

[0162] FIG. 6 is a perspective view of a structural catalyst 10 according to the present invention. The structural catalyst 10 includes a macrostructure coated with a ceramic coating impregnated with a catalytically active material. Within the structural catalyst are channels 70 extending along the length of the macrostructure 5 (indicated by the arrow "h" in FIG. 6), the channels being defined by walls 75. In the embodiment shown in FIG. 6, the walls 75 define multiple parallel, square channels 70 when viewed in the direction of flow, as indicated by arrow 12. When viewed from above, the structural catalyst 10 has a substantially square perimeter defined by edge lengths e1 and e2. However, the perimeter could also be circular or another shape.

[0163] The walls 75 of the structural catalyst 10 are a ceramic coating, such as an oxide-coated extruded or 3D-printed material, applied to the macrostructure. The ceramic coating is not shown in the figures. The ceramic coating is impregnated with catalytically active material. The ceramic coating, and therefore the catalytically active material, is present on all walls within the structural catalyst 10 through which the gas stream flows during operation and interacts with the heated surfaces and catalytically active material of the structural catalyst.

[0164] Thus, during use in a reactor system for the reverse water gas shift reaction, the feedstock flows through the channels 70 and interacts with the heated surface of the structural catalyst and the catalytically active material supported by the ceramic coating.

[0165] In the structural catalyst 10 shown in Figure 6, slits 60 are cut into the structural catalyst 10. The slits 60 force current to take a zigzag path within the macrostructure, in this example downward followed by upward, thereby increasing the current path and therefore resistance and therefore heat dissipated within the macrostructure. The slits 60 in the macrostructure may be provided with embedded insulating material to prevent current flow across the slits 60.

[0166] The channels 70 in the structured catalyst 10 are open at both ends. When the structured catalyst is used in a reactor system, the feedstock flows through the unit in the direction indicated by arrows 11 and 12 in FIGS. 1a and 1b and is heated by contact with and thermal radiation from the walls 75 of the channels 70. This heat initiates the desired reverse water-gas shift reaction. The walls 75 of the channels 70 may have a thickness of, for example, 0.5 mm, and the ceramic coating on the walls 75 may have a thickness of, for example, 0.1 mm. Although arrows 11 and 12 (see FIGS. 1a and 1b) indicate that the feedstock flow is downflow, the opposite flow direction, i.e., upflow, is also contemplated.

[0167] FIG. 7 shows a perspective view of the structural catalyst 10 of FIGS. 1A and 1B with connectors 7 attached. Each connector 7 connects a portion of the structural catalyst 10 to a conductor 40. Each conductor 40 is connected to a power source (not shown). Each connector 7 is connected to the top of the structural catalyst. When a conductor 40 is connected to a power source, current is conducted through the conductor to the corresponding connector 7 and flows through the structural catalyst 10. The slits 60 prevent lateral (horizontal in FIG. 7 ) current flow throughout the entire length of the structural catalyst 10 along its height h. Thus, current flows downward along the slits 60 in FIG. 7 , then laterally below the slits 60 in FIG. 7 , and finally upward along the length of the structural catalyst to reach the other connectors 7. The connectors 7 in FIG. 7 are mechanically fastened to the structural catalyst by mechanical fastening means, such as screws or bolts. However, additional or alternative fastening means are also contemplated. In one embodiment, the power supply generates a voltage of 3 V and a current of 400 A. The connector 7 is made of a material such as, for example, iron, aluminum, nickel, copper or alloys thereof.

[0168] As described above, the structural catalyst 10 is coated with a ceramic coating, such as an oxide, that supports catalytically active materials. However, the portion of the structural catalyst 10 that connects to the connector 7 must not be coated with an oxide. Instead, the macrostructure of the structural catalyst must be directly exposed or connected to the connector 7 to ensure good electrical connection between the macrostructure and the connector.

[0169] If connector 7 and, therefore, conductor 40 are connected to the same end of structural catalyst 10, i.e., the top end as seen in Figure 7, the feedstock entering the reactor system containing structural catalyst 10 will be able to cool connector 7 and conductor 40. For example, the feedstock entering such a reactor system may have a temperature of 200°C or 400°C, thus preventing connector 7 and conductor 40 from reaching temperatures much higher than this temperature.

[0170] FIG. 8 shows another embodiment of a structural catalyst 10'' having connectors 7''. The structural catalyst 10''' is, for example, the structural catalyst as shown in FIG. 6. Each of the connectors 7''' (not shown) has three holes on its upper side for connecting to conductors. Inside the slits 60 (see FIG. 6) of the structural catalyst 10''' is a piece of electrical insulating material 61.

[0171] Figure 9 shows the thermodynamic equilibrium of the methanation and reverse water-gas shift reactions as a function of temperature when using a 66.67% H2 / 33.3% CO2 mixture as the feedstock at 29 barg pressure. The figure shows that increasing the reactor system outlet temperature increases selectivity for CO and reduces the by-product CH4. Operating at an outlet temperature of 500 °C, a gas with an H2 / CO ratio of 9.0 is produced, which decreases to 1.7 when the temperature is increased to 1000 °C. The methane concentration also decreases from 22.7% at 500 °C to 0.6% at 1000 °C. Thus, by tuning the reverse water-gas shift reaction toward CO as the operating temperature increases, it is possible to selectively produce CO-rich synthesis gas.

[0172] 10 illustrates one embodiment of the process in which H is mixed and compressed in compressor 130 to form a gas phase feedstock. In parallel, a CO feedstock is compressed in compressor 120 and sent along with the H feedstock to reactor system 100, where the temperature is increased while promoting at least the reverse water gas shift reaction, providing hot synthesis gas as a first product gas. Alternatively, the compression of CO and H can be performed in a combined compressor.

[0173] Figure 11 shows a similar process embodiment to Figure 11, but with an upgrading unit including a flash separation unit 152 and a CO2 removal unit 151. The first product gas from the reactor system 100 is cooled in a heat exchange unit 141 to below the dew point of the water in the stream. The liquid water is separated in a flash separation unit 152 to produce a condensate and a dry product gas. The dry product gas is sent to a CO2 removal unit 151, where the CO2 is separated into an off-gas stream comprising substantially pure CO2, leaving an upgraded synthesis gas stream. The substantially pure CO2 2 The off-gas stream is recycled back to the CO2 compressor 120 and used as a feedstock for the reactor system 100.

[0174] FIG. 12 illustrates a process embodiment similar to FIG. 12, but including an upgrading unit including a flash separation unit 152 and a membrane 153. The first product gas from the reactor system 100 is cooled in a heat exchange unit 141 to below the dew point of the water in the stream. The liquid water is separated in a flash separation unit 152 to produce a condensate and a dry product gas. The dry product gas is sent to a membrane unit 153, where primarily CO and H permeate the membrane to produce an off-gas stream, leaving behind an upgraded syngas stream. The off-gas stream is partially recycled to the reactor system through the use of a dedicated compressor 155.

[0175] Figure 13 shows a similar process embodiment to Figure 13, but including a cold box 159 unit. The stream from the CO2 removal unit 151 is sent to the cold box unit 159, which produces an off-gas stream consisting primarily of CH4 and H2, and two upgraded syngas streams, one rich in H2 and one rich in CO2.

[0176] It should be noted that although the structural catalysts are shown in the figures as channels with square cross sections when viewed perpendicular to the z-axis, the channel cross sections can be of any suitable shape. Thus, the structural catalyst channels can alternatively be, for example, triangular, hexagonal, octagonal, or circular, with triangular, square, and hexagonal shapes being preferred.

[0177] The present invention has been illustrated by the description of various embodiments and examples, and while these embodiments and examples have been described in considerable detail, it is not the intention of the applicants to limit, or in any way restrict, the scope of the appended claims to such details. Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicants' general inventive concept. [Example]

[0178] Example 1 In one example of the present invention, the process comprises a 1675 Nm2 reactor having a pressure of 29.2 barg and a temperature of 260°C. 3 The reaction conditions included initial reaction condition A, a feedstock consisting of 59.7% H2O and 40.3% CO2, with a total flow rate of 1 / h. Upon supplying a first power of 32.6 kW, a near-equilibrium gas mixture consisting of 32.8% H2O, 17.6% H2, 28.4% CO2, 9.7% CO, and 11.6% CH4 was produced at 1361 Nm3. 3 It is produced at a temperature of 700°C at a pressure of 29.1 barg with a total flow rate of / h.

[0179] Switching to condition B over approximately 70 minutes while applying a second power of 804 kW resulted in a 1669 Nm2 reactor with a temperature of 1035°C at a pressure of 29.1 barg. 3 At a total flow rate of / h, a nearly equilibrium gas mixture consisting of 27.7% H2O, 31.9% H2, 12.9% CO2, 27.3% CO, and 0.2% CH4 is produced.

[0180] Example 2 Figure 14 shows experimental data from a test using a reactor system according to the invention with an FeCrAl macrostructure, a ZrO2-type ceramic coating, and Ni catalytically active material, using a method according to the invention in which the outlet temperature from the reactor system is increased from 400 to 1000°C, and using a feedstock with a H2 and CO2 ratio of 2.25 at 10 barg. Figure 14 shows a comparison of data points from the experiment with the expected composition when the reverse water gas shift reaction and methanation reaction are in equilibrium. CO2 conversion increases with temperature, with CO and H2O being produced. 800°C super At this temperature, the outlet mixture is close to equilibrium. less than At this temperature, CH4 is produced by methanation, but at higher temperatures CH4 is converted to CO and H2 by reverse methanation, and the CH4 slip becomes very small at higher outlet temperatures.

[0181] Example 3 FIG. 15 shows reaction simulation data from a model using a reactor system according to the invention with an FeCrAl macrostructure with a ZrO type ceramic coating, and Ni catalytically active material, using a feed of 36 NL / h H and CO at 10 barg with a ratio of 2.25 and an inlet temperature of 200° C., resulting in a reaction of 7.5 kW / m 2The figure shows the temperature increase with a constant heat flux of 0.01. The catalyst structure has a cylindrical channel with a length of 12 cm and a diameter of 5 mm. The simulation was based on the kinetics of Xu & Froment (1989) with the physical constants approximated by Chapman-Emskogg. The figure shows the evolution of the temperature, heat of reaction, and mole fractions of CO and CH4 along the reaction length in the reactor. The temperature increases continuously along the reaction length, but is shown to increase at an accelerated rate initially and plateau within the reactor. This behavior is explained by the reaction scheme being exothermic in the first part of the reactor up to 17 mm (i.e., 14% of the reaction length), as indicated by the heat of reaction initially increasing to a positive value (exothermic) before switching to a negative value (endothermic) after 14% of the reaction length. This behavior can be understood by the rapid production of methane by methanation during the initial part of the reaction time. This methane is then converted to CO by reverse methanation in parallel with the reverse water gas shift reaction, ultimately yielding a product gas with a high CO concentration.

[0182] Example 4 FIG. 16 shows three reactor simulation data from a model using a reactor system according to the invention with a FeCrAl macrostructure with a ZrO type ceramic coating, and Ni catalytically active material, using a feed of 36 NL / h H and CO at 10 barg with a ratio of 2.25 and an inlet temperature of 200° C., generating 2.5 kW / m 2The temperature is increased using a constant heat flux of 1000 kJ / cm. The catalyst structure has a cylindrical channel with a length of 12 cm and a diameter of 5 mm. The simulations were based on the kinetics of Xu & Froment (1989) with the physical constants approximated by Chapman-Emskogg. In the three simulations, different lengths of ceramic coating with catalytically active material, i.e., the catalyst hardware, transition from a ZrO2-only ceramic coating to a Ni-supported ceramic coating at 0%, 17%, and 50% of the total length of the macrostructure. This represents three embodiments of the system, and Figure 16a shows how the initial exothermic behavior of the reaction can be controlled. Figure 16b shows that the maximum carbon potential can be reduced by changing the starting point of the catalyst material to the high temperature part of the reactor. Carbon activity (a C ) is evaluated according to the following:

[0183] a c =K eq (COred) * p(CO) * p(H2) / p(H2O) where K eq (COred) is the thermodynamic equilibrium constant for the CO reduction reaction, and p(i) is the partial pressure of i. Here, a c It should be noted that if <1, no carbon formation occurs.

[0184] Example 5 FIG. 17 shows comparative reactor simulations, comparing a model using a reactor system according to the present invention with a FeCrAl macrostructure with a ZrO2-type ceramic coating and a Ni catalytically active material that catalyzes both methanation and reverse water gas shift, with a feed of 36 NL / h H2 to CO2 of 2.25 and an inlet temperature of 200°C at 10 barg and an increased temperature in the reactor system (labeled "active for methanation and RWGS"), with a model using a FeCrAl macrostructure with a ZrO2-type ceramic coating and a catalytically active material that is selective for the reverse water gas shift reaction only, with a feed of 2.25 H2 to CO2 and an inlet temperature of 200°C at 10 barg and an increased temperature in the reactor system (labeled "selective for RWGS"). In both simulations, a 2.5 kW / m 2 A flux of 1000kJ / cm was used. In both simulations, the catalyst structure used a cylindrical channel with a length of 12 cm and a diameter of 5 mm. Simulations were performed based on the kinetics of Xu & Froment (1989) with the physical constants approximated by Chapman-Emskogg. Figure 17 shows the carbon activity for the CO reduction reaction on the catalyst surface, clearly demonstrating how the critical zone where carbon formation is thermodynamically driven is significantly reduced when using a nonselective catalyst system catalyzing both methanation and reverse water-gas shift (RWSS), since in this case the carbon activity for CO reduction is much lower throughout the reaction zone.

[0185] Example 6 Figure 18 shows experimental data from a test using a reactor system with an FeCrAl macrostructure with a ZrO2-type ceramic coating and Ni catalytically active material in the downstream 50% of the reactor length, using a feedstock of 10 barg and a H2 to CO2 ratio of 2.25, while increasing the outlet temperature from the reactor system to 400-1000°C using a method according to the present invention. Figure 18 shows the outlet temperature versus the CO2 and methane mole fraction in the product gas analyzed by gas chromatography. Figure 18 shows that increasing the outlet temperature reduced the methane concentration in the product gas, enabling stable operation for over 80 hours.

[0186] The following numbered items are available:

[0187] Item 1. 1. A reactor system for conducting a reverse water-gas shift reaction to produce a first product gas comprising CO from a feedstock comprising CO and H, comprising: -Providing feedstocks containing CO2 and H2; - A structural catalyst comprising a macrostructure of conductive material and a catalytically active material capable of catalyzing both the reverse water gas shift reaction and the methanation reaction; the structural catalyst configured to operate under temperatures and pressures such that both the reverse water gas shift reaction and the methanation reaction occur; a pressure shell containing the structural catalyst, wherein the pressure shell includes an inlet for admitting the feedstock and an outlet for discharging a product gas, the inlet positioned such that the feedstock enters the structural catalyst at a first end thereof and the product gas exits the structural catalyst at a second end thereof; - a thermal insulation layer provided between the structural catalyst and the pressure shell; at least two conductors electrically connected to the structural catalyst and a power source disposed outside the pressure shell; wherein the power source is dimensioned to pass an electric current through the macrostructure to heat at least a portion of the structural catalyst to a temperature of at least 500°C, and wherein the at least two conductors are connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than to the second end of the structural catalyst, and the structural catalyst is configured to pass an electric current from one conductor to the second end of the structural catalyst and back to the second ends of the at least two conductors; an outlet for the first product gas containing CO The reactor system comprising:

[0188] Item 2. Item 1. The reactor system of item 1, wherein the macrostructure supports a ceramic coating. Item 3. 3. The reactor system of claim 2, wherein the ceramic coating at least partially supports a catalytically active material. Item 4. 5. The reactor system according to any one of items 1 to 4, wherein the structural catalyst has a first reaction zone disposed closest to a first end of the structural catalyst, the first reaction zone having an overall exothermic reaction, and a second reaction zone disposed closest to a second end of the structural catalyst, the second reaction zone having an overall endothermic reaction. Item 5. 5. The reactor system of claim 4, wherein the first reaction zone extends over 5% to 60% of the length of the structure catalyst from its first end to its second end.

[0189] Item 6. 6. The reactor system of any one of items 1 to 5, wherein a methane concentration is higher in the partially catalyzed feedstock within at least a portion of the structured catalyst than in the feedstock and the first product gas. Item 7. 7. The reactor system according to any one of items 1 to 6, wherein the temperature of the structure catalyst increases continuously from the first end to the second end of the structure catalyst. Item 8. 8. The reactor system according to any one of items 1 to 7, wherein the power supply is dimensioned to heat at least a portion of the structured catalyst to a temperature of at least 500°C, preferably at least 600°C, preferably at least 700°C, preferably at least 800°C, preferably at least 900°C, preferably at least 1000°C, and most preferably at least 1100°C. Item 9. 9. The reactor system according to any one of items 1 to 8, wherein the feedstock further comprises N2, CO, CH4, a higher hydrocarbon, and / or Ar. Item 10. 10. The reactor system according to any one of items 1 to 9, wherein the pressure shell has a design pressure between 2 and 30 bar, preferably 4 and 25 bar, more preferably 6 and 20 bar, even more preferably 7 and 15 bar, and most preferably 8 and 12 bar.

[0190] Item 11. 7. The reactor system according to any one of items 1 to 6, wherein the pressure shell has a design pressure between 30 and 200 bar. Item 12. The resistivity of a conductive material is 10 -5 Ω·m~10 -7 12. The reactor system according to any one of items 1 to 11, wherein the resistance is between Ω·m. Item 13. 13. The reactor system according to any one of items 1 to 12, wherein the at least two conductors are routed through the pressure shell at fittings such that the at least two conductors are electrically isolated from the pressure shell. Item 14. Item 14. The reactor system of item 13, wherein the pressure shell further comprises one or more inlets near or in combination with at least one fitting to allow cooling gas to flow over, around, near or within at least one conductor within the pressure shell. Item 15. 15. The reactor system according to any one of items 1 to 14, wherein the reactor system further comprises an inner tube in a heat exchange relationship with the structure catalyst but electrically insulated from the structure catalyst, the inner tube adapted to withdraw product gas from the structure catalyst such that the product gas flowing through the inner tube is in a heat exchange relationship with the gas flowing over the structure catalyst.

[0191] Item 16. 16. The reactor system according to any one of items 1 to 15, wherein the connection between the structural catalyst and the at least two conductors is a mechanical connection, a welded connection, a brazed connection, or a combination thereof. Item 17. 17. The reactor system according to any one of items 1 to 16, wherein the electrically conductive material comprises a 3D printed or extruded and sintered macrostructure, the macrostructure supporting a ceramic coating, and the ceramic coating supporting a catalytically active material. Item 18. 18. The reactor system according to any one of items 1 to 17, wherein the structural catalyst comprises an array of macrostructures electrically connected to each other. Item 19. 19. The reactor system according to any one of items 1 to 18, wherein the structural catalyst has an electrically insulating component arranged so that the length of the main current path between the at least two conductors is longer than the maximum dimension of the structural catalyst. Item 20. 20. The reactor system according to any one of items 1 to 19, wherein the structure catalyst has at least one electrically insulating component arranged to direct current through the structure catalyst such that the current density vector of the main current path has a non-zero component value parallel to the length of the structure catalyst for at least 70% of the length of the structure catalyst.

[0192] Item 21. 21. The reactor system according to any one of items 1 to 20, wherein the macrostructure has a plurality of parallel channels, a plurality of non-parallel channels, and / or a plurality of labyrinth-like channels. Item 22. 22. The reactor system of any one of items 1 to 21, wherein the reactor system further comprises a bed of a second catalyst material upstream of the structural catalyst within the pressure shell. Item 23. 23. The reactor system according to any one of items 1 to 22, wherein the reactor system further comprises a third catalyst material in the form of catalyst pellets, extrudates or granules loaded into the channels of the macrostructure. Item 24. 24. The reactor system of any one of items 1 to 23, wherein the reactor system further comprises a bed of a fourth catalyst material downstream of the structural catalyst within the pressure shell. Item 25. The macrostructure material is heated by resistance heating of the material at a rate of 500 to 100,000 W / m 2 25. The reactor system according to any one of items 1 to 24, wherein the material is selected to generate a heat flux of 1000 W / m.s.

[0193] Item 26. 26. The reactor system according to any one of items 1 to 25, wherein the structure catalyst comprises a first portion arranged to generate a first heat flux and a second portion arranged to generate a second heat flux, the first heat flux being lower than the second heat flux, and the first portion being upstream of the second portion. Item 27. 27. The reactor system according to any one of items 1 to 26, wherein the structure catalyst comprises a third section arranged to generate a third heat flux, the third heat flux being lower than the first heat flux and / or the second heat flux, and the third section is downstream of the first section and / or the second section. Item 28. 28. The reactor system according to any one of items 1 to 27, further comprising a control system arranged to control a power supply to ensure that the temperature of the gas exiting the pressure shell is within a predetermined range and / or to ensure that the conversion of the feedstock is within a predetermined range. Item 29. 29. The reactor system according to any one of items 1 to 28, wherein the ratio of the area-equivalent diameter of a horizontal cross section passing through the structure catalyst to the height of the structure catalyst is in the range of 0.1 to 2.0. Item 30. 30. The reactor system according to any one of items 1 to 29, wherein the height of the reactor system is 0.5 to 7 m, more preferably 0.5 to 3 m.

[0194] Item 31. 31. The reactor system according to any one of items 1 to 30, wherein the length of the gas passage through the structure catalyst is shorter than the length of the passage of the electric current from one electrode through the structure catalyst to the next electrode. Item 32. 32. The reactor system according to any one of items 4 to 31, wherein the reactor system is arranged so that the outlet temperature of the product stream from the second reaction zone is between 500 and 1300°C, for example between 800 and 1100°C, preferably between 850 and 1050°C.

[0195] Item 33. 1. A method for converting a feedstock comprising CO and H into a first product gas comprising CO in a reactor system including a pressure shell containing a structural catalyst comprising a macrostructure of an electrically conductive material and a catalytically active material; the reactor system including thermal insulation between the structural catalyst and the pressure shell; and the method comprising the steps of: - providing a pressurized feedstock; - feeding the pressurized feedstock into the pressure shell through an inlet positioned at a first end of the structural catalyst such that the feedstock enters the structural catalyst; -using a catalytically active material capable of catalyzing both the reverse water gas shift reaction and the methanation reaction; - subjecting the feedstock to a reverse water gas shift reaction over the structured catalyst at a temperature and pressure such that both the reverse water gas shift reaction and the methanation reaction occur; - discharging a product gas from the pressure shell, wherein the product gas exits the structural catalyst at a second end of the structural catalyst; - supplying electrical power via electrical conductors connecting a power source located outside the pressure shell to the structural catalyst, causing an electrical current to flow through the macrostructure, thereby heating at least a portion of the structural catalyst to a temperature of at least 500°C, the at least two conductors being connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than the second end of the structural catalyst, and the structural catalyst being configured to pass electrical current from one conductor substantially to the second end of the structural catalyst and back to a second conductor of the at least two conductors, thereby heating at least a portion of the structural catalyst to a temperature sufficient for the feedstock to undergo a reverse water gas shift reaction on the structural catalyst; discharge a first product gas comprising CO from the reactor system; A method comprising:

[0196] Item 34. Item 34. The method of item 33, wherein the macrostructure supports a ceramic coating. Item 35. 35. The method of claim 34, wherein the ceramic coating supports a catalytically active material.

[0197] Item 36. 36. The method according to any one of items 33 to 35, wherein the structural catalyst has a first reaction zone disposed closest to a first end of the structural catalyst, the first reaction zone having an overall exothermic reaction, and a second reaction zone disposed closest to a second end of the structural catalyst, the second reaction zone having an overall endothermic reaction. Item 37. 37. The method according to any one of items 33 to 36, wherein the first reaction zone extends over 5% to 60% of the length of the structural catalyst from its first end to its second end. Item 38. 38. The method of any one of items 33 to 37, wherein the methane concentration is higher in the partially catalyzed feedstock within at least a portion of the structured catalyst than in the feedstock and the first product gas. Item 39. 39. The method according to any one of items 33 to 38, wherein the temperature of the structural catalyst is increased continuously from the first end to the second end of the structural catalyst. Item 40. 40. The method according to any one of items 33 to 39, wherein the feedstock is pressurized to a pressure between 2 and 30 bar, preferably 4 and 25 bar, more preferably 6 and 20 bar, even more preferably 7 and 15 bar, and most preferably 8 and 12 bar.

[0198] Item 41. 41. The method according to any one of items 33 to 40, wherein the feedstock is pressurized to a pressure between 30 and 200 bar. Item 42. 42. The method according to any one of items 33 to 41, wherein the feedstock further comprises N2, CO, CH4, higher hydrocarbons and / or Ar. Item 43. 43. The method according to any one of items 33 to 42, wherein at least a portion of the structured catalyst is heated to a temperature of at least 500°C, preferably at least 600°C, preferably at least 700°C, preferably at least 800°C, preferably at least 900°C, preferably at least 1000°C, most preferably at least 1100°C. Item 44. 44. The method of any one of items 33 to 43, further comprising the step of flowing a cooling gas through an inlet through the pressure shell so that the cooling gas flows over at least one conductor. Item 45. 45. The method of any one of items 33 to 44, further comprising the step of feeding the first product gas comprising synthesis gas to an upgrading unit and separating it into an upgraded synthesis gas stream and one or more off-gas streams. Item 46. 46. ​​The method of any one of items 33 to 45, further comprising recycling one or more of the off-gas streams to a unit upstream of the upgrading unit.

[0199] Item 47. A method for rapidly switching a reverse water gas shift reaction of a CO2-containing feedstock from a first steady-state reaction condition (A) to a second steady-state reaction condition (B) or vice versa in the reactor system according to any one of items 1 to 29, comprising the steps of: In the first steady-state reaction condition (A), - feeding the feedstock into the reactor system at a first total flow rate; and - providing a first electrical power through an electrical conductor connecting a power source located outside the pressure shell to the structural catalyst, thereby causing a first electrical current to flow through the electrically conductive material; whereby at least a portion of the structural catalyst is heated to a first temperature at which the feedstock is converted over the structural catalyst under the first steady-state reaction conditions (A) into a first product gas; and discharging the first product gas from the reactor system; Then, under the second steady-state reaction conditions (B), - feeding the feedstock into the reactor system at a second total flow rate; and - providing a second electrical power through an electrical conductor connecting a power source located outside the pressure shell to the structural catalyst, thereby causing a second electrical current to flow through the electrically conductive material; thereby heating at least a portion of the structural catalyst to a second temperature; at which temperature the feedstock is converted over the structural catalyst under the second steady-state reaction conditions (B) into a second product gas; and discharging the second product gas from the reactor system; Including, wherein the second power is greater than the first power; and / or the second total flow rate is greater than the first total flow rate.

[0200] Item 48. Item 48. The method of claim 47, wherein the at least two conductors are connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than the second end of the structural catalyst, and the structural catalyst is constructed to allow current to flow from one conductor substantially to the second end of the structural catalyst and back to the second of the at least two conductors. Item 49. 49. The method according to any one of items 47 to 48, wherein the ratio (A:B) of the total gas supply flow rate under the first reaction condition A to the second reaction condition B is at least 1:10. Item 50. 49. The method according to any one of Items 47 to 49, wherein the outlet temperature of the product gas from the structure catalyst under reaction condition B is 50°C to 800°C higher, for example, 100°C to 500°C higher, and preferably 150°C to 400°C higher, than the outlet temperature of the product gas from the structure catalyst under reaction condition A.

[0201] Item 51. 51. The method according to any one of items 47 to 50, wherein switching between reaction conditions A and B comprises gradually changing the total gas supply flow rate from the first total flow rate to the second total flow rate and simultaneously gradually changing the applied potential on the conductive material from the first power to the second power. Item 52. 52. The method according to any one of items 47 to 51, wherein the product gas outlet temperature from the structure catalyst under reaction condition B is not higher than the product gas outlet temperature from the structure catalyst under reaction condition A by more than 50°C. Item 53. 53. The method of any one of items 47 to 52, wherein a proportional-integral-derivative (PID) controller controls the potential based on a feedback reading of a process value of the product gas outlet temperature from the structure catalyst. Item 54. 54. The method according to any one of items 47 to 53, wherein the product gas outlet temperature from the structure catalyst is measured at the surface immediately below or at the most downstream surface of the structure catalyst. Item 55. 55. The method according to any one of items 47 to 54, wherein the switching between reaction conditions A and B is carried out over a period of less than 3 hours, such as less than 2 hours, for example less than 60 minutes, preferably less than 30 minutes, even more preferably less than 15 minutes.

[0202] Item 56. 56. The method according to any one of items 47 to 55, wherein switching between reaction conditions A and B comprises supplying a second power to the structure catalyst. Item 57. 57. The method according to any one of items 47 to 56, wherein the switching between reaction conditions A and B comprises a transition state between the reaction conditions A and B; and the transition state comprises a first period during which power is turned off, followed by a second period during which the second power of condition B is supplied to the structure catalyst. Item 58. 58. The method according to any one of items 47 to 57, wherein the switching between the reaction conditions A and B comprises a transition state between the reaction conditions A and B; the transition state comprises a first period in which a third power is supplied to the structure catalyst, and then a second period in which a second power of condition B is supplied to the structure catalyst, and the third power is greater than the second power. Furthermore, the present invention includes the following items. [Item 1] CO 2 and H 2 1. A reactor system for conducting a reverse water gas shift reaction to produce a first product gas comprising CO from a feedstock comprising: -CO 2 and H 2 Supply of feedstocks, including; - A structural catalyst comprising a macrostructure of conductive material and a catalytically active material capable of catalyzing both the reverse water gas shift reaction and the methanation reaction; said structural catalyst configured to operate under a temperature and pressure such that both said reverse water-gas reaction and said methanation reaction occur; a pressure shell containing the structural catalyst, wherein the pressure shell includes an inlet for admitting the feedstock and an outlet for discharging a product gas, the inlet positioned such that the feedstock enters the structural catalyst at a first end thereof and the product gas exits the structural catalyst at a second end thereof; - a thermal insulation layer provided between the structural catalyst and the pressure shell; at least two conductors electrically connected to the structural catalyst and a power source disposed outside the pressure shell; wherein the power source is dimensioned to pass an electric current through the macrostructure to heat at least a portion of the structural catalyst to a temperature of at least 500°C, and wherein the at least two conductors are connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than to the second end of the structural catalyst, and the structural catalyst is configured to pass an electric current from one conductor to the second end of the structural catalyst and back to the second ends of the at least two conductors; an outlet for the first product gas containing CO The reactor system comprising: [Item 2] Item 1. The reactor system of item 1, wherein the macrostructure supports a ceramic coating. [Item 3] 3. The reactor system of claim 2, wherein the ceramic coating at least partially supports a catalytically active material. [Item 4] 4. The reactor system according to item 2 or 3, wherein the ceramic coating supports catalytically active material in a most downstream portion of the structure catalyst, for example, in 10 to 100%, preferably 30 to 100%, more preferably 50 to 100% of the length of the structure catalyst from its first end to its second end. [Item 5] 5. The reactor system according to any one of items 1 to 4, wherein the structural catalyst has a first reaction zone disposed closest to a first end of the structural catalyst, the first reaction zone having an overall exothermic reaction, and a second reaction zone disposed closest to a second end of the structural catalyst, the second reaction zone having an overall endothermic reaction. [Item 6] 6. The reactor system of claim 5, wherein the first reaction zone extends over 5% to 60% of the length of the structure catalyst from its first end to its second end. [Item 7] 7. The reactor system of any one of items 1 to 6, wherein a methane concentration is higher in the partially catalyzed feedstock within at least a portion of the structured catalyst than in the feedstock and the first product gas. [Item 8] 8. The reactor system according to any one of items 1 to 7, wherein the temperature of the structure catalyst increases continuously from the first end to the second end of the structure catalyst. [Item 9] 9. The reactor system according to any one of items 1 to 8, wherein the power supply is dimensioned to heat at least a portion of the structured catalyst to a temperature of at least 500°C, preferably at least 600°C, preferably at least 700°C, preferably at least 800°C, preferably at least 900°C, preferably at least 1000°C, and most preferably at least 1100°C. [Item 10] In a reactor system including a pressure shell containing a structure catalyst including a macrostructure of conductive material and a catalytically active material, 2 and H 2 1. A method for converting a feedstock comprising: - providing a pressurized feedstock; - feeding the pressurized feedstock into the pressure shell through an inlet positioned at a first end of the structural catalyst such that the feedstock enters the structural catalyst; -using a catalytically active material capable of catalyzing both the reverse water gas shift reaction and the methanation reaction; - subjecting the feedstock to a reverse water gas shift reaction over the structured catalyst at a temperature and pressure such that both the reverse water gas shift reaction and the methanation reaction occur; - discharging a product gas from the pressure shell, wherein the product gas exits the structural catalyst at a second end of the structural catalyst; - supplying electrical power via electrical conductors connecting a power source located outside the pressure shell to the structural catalyst, causing an electrical current to flow through the macrostructure, thereby heating at least a portion of the structural catalyst to a temperature of at least 500°C, the at least two conductors being connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than the second end of the structural catalyst, and the structural catalyst being configured to pass electrical current from one conductor substantially to the second end of the structural catalyst and back to a second conductor of the at least two conductors, thereby heating at least a portion of the structural catalyst to a temperature sufficient for the feedstock to undergo a reverse water gas shift reaction on the structural catalyst; discharge a first product gas comprising CO from the reactor system; A method comprising: [Item 11] Item 11. The method of item 10, wherein the structural catalyst has a first reaction zone disposed proximate a first end of the structural catalyst, the first reaction zone having an overall exothermic reaction, and a second reaction zone disposed proximate a second end of the structural catalyst, the second reaction zone having an overall endothermic reaction. [Item 12] Item 12. The method of claim 11, wherein the first reaction zone extends over 5% to 60% of the length of the structure catalyst from its first end to its second end. [Item 13] 13. The method of any one of items 10 to 12, wherein the methane concentration is higher in the partially catalyzed feedstock within at least a portion of the structured catalyst than in the feedstock and the first product gas. [Item 14] 14. The method according to any one of items 10 to 13, wherein the temperature of the structural catalyst is increased continuously from the first end to the second end of the structural catalyst. [Item 15] 15. The method according to any one of items 10 to 14, wherein the power supply is dimensioned to heat at least a portion of the structure catalyst to a temperature of at least 500°C, preferably at least 600°C, preferably at least 700°C, preferably at least 800°C, preferably at least 900°C, preferably at least 1000°C, and most preferably at least 1100°C. [Item 16] 16. The method according to any one of items 10 to 15, wherein the pressure of the structure catalyst is 2 to 30 bar, preferably 4 to 25 bar, more preferably 6 to 20 bar, even more preferably 7 to 15 bar, and most preferably 8 to 12 bar. [Item 17] 17. The method of any one of items 10 to 16, further comprising the step of feeding the first product gas comprising synthesis gas to an upgrading unit and separating it into an upgraded synthesis gas stream and one or more off-gas streams. [Item 18] In the reactor system according to any one of items 1 to 9, 2 1. A method for rapidly switching a reverse water gas shift reaction of a feedstock comprising: Under the first steady-state reaction conditions (A), - feeding the feedstock into the reactor system at a first total flow rate; and - providing a first electrical power through an electrical conductor connecting a power source located outside the pressure shell to the structural catalyst, thereby causing a first electrical current to flow through the electrically conductive material; whereby at least a portion of the structural catalyst is heated to a first temperature at which the feedstock is converted over the structural catalyst under the first steady-state reaction conditions (A) into a first product gas; and discharging the first product gas from the reactor system; Then, under the second steady-state reaction conditions (B), - feeding the feedstock into the reactor system at a second total flow rate; and - providing a second electrical power through an electrical conductor connecting a power source located outside the pressure shell to the structural catalyst, thereby causing a second electrical current to flow through the electrically conductive material; thereby heating at least a portion of the structural catalyst to a second temperature; at which temperature the feedstock is converted over the structural catalyst under the second steady-state reaction conditions (B) into a second product gas; and discharging the second product gas from the reactor system; Including, wherein the second power is greater than the first power; and / or the second total flow rate is greater than the first total flow rate. [Item 19] Item 19. The method according to item 18, wherein the ratio (A:B) of total gas supply flow rates under the first reaction conditions A and the second reaction conditions B is at least 1:10.

Claims

1. CO ２ and H ２ 1. A reactor system for conducting a reverse water-gas shift reaction to produce a first product gas comprising CO from a feedstock comprising: -CO ２ and H ２ supply of feedstocks including; - a structural catalyst comprising a macrostructure of conductive material and a catalytically active material capable of catalyzing both the reverse water gas shift reaction and the methanation reaction; - said structural catalyst configured to operate under temperatures and pressures such that both said reverse water gas reaction and said methanation reaction occur; a pressure shell containing the structural catalyst, wherein the pressure shell includes an inlet for admitting the feedstock and an outlet for discharging product gas, the inlet positioned such that the feedstock enters the structural catalyst at a first end thereof and the product gas exits the structural catalyst at a second end thereof; - a thermal insulation layer provided between the structural catalyst and the pressure shell; at least two conductors electrically connected to the structural catalyst and a power source located outside the pressure shell; wherein the power source is sized to pass an electric current through the macrostructure to heat at least a portion of the structural catalyst to a temperature of at least 500°C, and wherein the at least two conductors are connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than to the second end of the structural catalyst, and the structural catalyst is configured to pass an electric current from one conductor to the second end of the structural catalyst and back to the second ends of the at least two conductors; an outlet for the first product gas containing CO Including, The reactor system is configured to raise the temperature of the feedstock at the inlet, which is between 200°C and 500°C, to a first product gas temperature of above 800°C.

2. The reactor system of claim 1 , wherein the macrostructure supports a ceramic coating.

3. 3. The reactor system of claim 2, wherein the ceramic coating at least partially supports a catalytically active material.

4. 4. The reactor system of claim 2 or 3, wherein the ceramic coating supports catalytically active material in a most downstream portion of the structural catalyst, for example, 10 to 100%, preferably 30 to 100%, more preferably 50 to 100% of the length of the structural catalyst from its first end to its second end.

5. In a reactor system including a pressure shell containing a structured catalyst including a macrostructure of conductive material and a catalytically active material, ２ and H ２ 1. A method for converting a feedstock comprising: - providing a pressurized feedstock; - feeding the pressurized feedstock into the pressure shell through an inlet positioned at a first end of the structural catalyst such that the feedstock enters the structural catalyst; - using a catalytically active material capable of catalyzing both the reverse water gas shift reaction and the methanation reaction; - subjecting the feedstock to a reverse water gas shift reaction over the structured catalyst at a temperature and pressure such that both the reverse water gas shift reaction and the methanation reaction occur; - discharging a product gas from the pressure shell, wherein the product gas exits the structural catalyst at a second end of the structural catalyst; - providing electrical power via electrical conductors connecting a power source located outside the pressure shell to the structural catalyst, causing an electrical current to flow through the macrostructure, thereby heating at least a portion of the structural catalyst to a temperature of at least 500°C, the at least two conductors being connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than the second end of the structural catalyst, and the structural catalyst being configured to pass electrical current from one conductor substantially to the second end of the structural catalyst and back to a second conductor of the at least two conductors, thereby heating at least a portion of the structural catalyst to a temperature sufficient for the feedstock to undergo a reverse water gas shift reaction on the structural catalyst; - discharging a first product gas comprising CO from the reactor system; Including, the reactor system has a configuration for increasing the temperature of the feedstock at the inlet, which is between 200°C and 500°C, to a temperature of the first product gas above 800°C; method.

6. 6. The method of claim 5, wherein the structural catalyst has a first reaction zone disposed proximate a first end of the structural catalyst, the first reaction zone having a generally exothermic reaction, and a second reaction zone disposed proximate a second end of the structural catalyst, the second reaction zone having a generally endothermic reaction.

7. 7. The method of claim 6, wherein the first reaction zone extends over 5% to 60% of the length of the structural catalyst from its first end to its second end.

8. 8. The method of any one of claims 5 to 7, wherein the methane concentration is higher in the partially catalyzed feedstock within at least a portion of the structured catalyst than in the feedstock and the first product gas.

9. The method of any one of claims 5 to 8, wherein the temperature of the structural catalyst increases continuously from the first end to the second end of the structural catalyst.

10. 10. The method of any one of claims 5 to 9, wherein the power supply is dimensioned to heat at least a portion of the structured catalyst to a temperature of at least 500°C, preferably at least 600°C, preferably at least 700°C, preferably at least 800°C, preferably at least 900°C, preferably at least 1000°C, and most preferably at least 1100°C.

11. The method according to any one of claims 5 to 10, wherein the pressure of the structured catalyst is from 2 to 30 bar, preferably from 4 to 25 bar, more preferably from 6 to 20 bar, even more preferably from 7 to 15 bar, and most preferably from 8 to 12 bar.

12. In the reactor system according to any one of claims 1 to 4, ２ 1. A method for rapidly switching a reverse water gas shift reaction of a feedstock comprising: In the first steady-state reaction condition (A), - feeding the feedstock into the reactor system at a first total flow rate; and - providing a first electrical power through an electrical conductor connecting a power source located outside the pressure shell to the structural catalyst, thereby causing a first electrical current to flow through the electrically conductive material; whereby at least a portion of the structural catalyst is heated to a first temperature at which the feedstock is converted over the structural catalyst under the first steady-state reaction conditions (A) into a first product gas; and discharging the first product gas from the reactor system; Then, under the second steady-state reaction conditions (B), - feeding the feedstock into the reactor system at a second total flow rate; and - providing a second electrical power through an electrical conductor connecting a power source located outside the pressure shell to the structural catalyst, thereby causing a second electrical current to flow through the electrically conductive material; thereby heating at least a portion of the structural catalyst to a second temperature; at which temperature the feedstock is converted over the structural catalyst under the second steady-state reaction conditions (B) into a second product gas; and discharging the second product gas from the reactor system; Including, wherein the second power is greater than the first power; and / or the second total flow rate is greater than the first total flow rate.

13. 13. The method of claim 12, wherein the ratio (A:B) of total gas supply flow rates under the first reaction condition A and the second reaction condition B is at least 1:10.

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