Reverse gas to water conversion unit distribution device

Abstract

A method and apparatus for producing synthesis gas by converting a feedstock containing CO2 in which CO2 (4) is treated with H2 (5) in a RWGS reaction unit (6) to produce a RWGS gas (7), the RWGS reaction unit comprising: a heating zone (A) for heating the CO2 and / or H2; a distribution zone (B) for uniformly distributing, in terms of gas velocity, a mixture comprising the heated CO2 and H2 to a reaction zone (C); and the reaction zone (C) comprising a catalytic bed for converting the CO2 and H2 into CO and H2O to produce the synthesis gas. Figure 1 to be published

Description

Title of the invention: Inverted gas to water conversion unit distribution device Technical field

[0001] The present invention relates to a device and a method for producing synthesis gas ("syngas" according to English terminology), mainly comprising carbon monoxide (CO) and optionally hydrogen (H2), by reaction between a stream comprising carbon dioxide (CO2) and optionally carbon monoxide and a stream comprising hydrogen.

[0002] The synthesis gas can then be used to produce alcohols, in particular methanol or paraffinic hydrocarbons such as synthetic fuels, namely gasoline, kerosene, diesel, and / or other hydrocarbon products, such as naphtha, or lubricating bases, of very high quality (essentially free of sulfur, aromatics, nitrogen). Prior art

[0003] The use of a reverse water-gas shift (RWGS) device for converting a mixture of carbon dioxide and hydrogen into synthesis gas comprising carbon monoxide and optionally H2 is known to those skilled in the art. During the RWGS reaction, carbon dioxide reacts with hydrogen to produce carbon monoxide and water. A mixture of carbon monoxide and hydrogen can be obtained by operating with an excess of hydrogen or by adding additional hydrogen at the reactor outlet, so as to obtain, after condensation of the water, a mixture comprising carbon monoxide, hydrogen and optionally unconverted carbon dioxide.

[0004] The reverse water gas shift reaction is a reversible and endothermic reaction, which is favored at high temperatures. At thermodynamic equilibrium, depending on the pressure and the H2 / CO2 ratio, the conversion of carbon dioxide can reach 60% to 80% for temperatures between 800°C and 1000°C. Hydrogen can also react with carbon dioxide and / or carbon monoxide to form methane. These reactions are exothermic and are therefore not favored at high temperatures, but are favored by a high partial pressure of hydrogen. These reactions which lead to the formation of methane consume a lot of hydrogen. When we want to produce a synthesis gas for the production of synthetic fuel or methanol, we try to limit the amount of methane present in the synthesis gas, in order to maximize the amount of liquid hydrocarbons synthesized. Carbon monoxide selectivity is therefore an important issue in limiting methane production and thus directing the hydrogen consumed towards the formation of carbon monoxide in order to maximize the production of liquid hydrocarbons.

[0005] The paper by Vazquez et al. in Journal of CO2 Utilization 28 (2018) pp 235-246 describes a RWGS unit associated with a hydrocarbon synthesis unit by Fischer-Tropsch synthesis. The source of CO2 that feeds the RWGS unit is CO2 captured from the air. The hydrogen that feeds the RWGS unit is produced by electrolysis of water and a hydrogen make-up stored in cylinders. The hydrogen and CO2 are mixed and then the mixture is preheated to 450°C before entering the RWGS reactor. The RWGS reactor contains a metal monolith covered with a catalytic phase made of precious metal. The reactor is heated from the outside by an electric furnace system to a maximum temperature of 850°C. The reactor is sized for a CO2 flow rate of 2 NL / min, or 0.12 Nm3 / h, and its diameter is 20 mm.This prior art does not allow us to design an industrial-scale RWGS unit, i.e. a larger diameter RWGS unit capable of processing gas flow rates at least greater than 1000 Nm3 / h. Furthermore, when heating the CO2 and hydrogen mixture between 450°C and 850°C, products such as methane and CO are formed within the RWGS reactor, thus creating conditions favorable to corrosion by metal dusting. Summary of the invention

[0006] In the context described above, a first object of the present description is to overcome the problems of the prior art and to provide a device and a method for producing synthesis gas from carbon dioxide and hydrogen, allowing an improved quality of the synthesis gas produced. The device and the method according to the invention make it possible in particular to avoid fluidizing the catalyst of the catalytic bed of the reaction zone and to improve the conversion by ensuring a homogeneous distribution in terms of concentration. The device and the method according to the invention also make it possible to reduce the quantity of methane present in the synthesis gas and limit the phenomena of metallic dusting.

[0007] According to a first aspect, the aforementioned objects, as well as other advantages, are obtained by a device for producing gas for converting gas to inverted water by converting a feedstock containing carbon dioxide, comprising the following elements: - a reverse water gas conversion reaction unit adapted to treat a carbon dioxide stream with a hydrogen stream, and produce a conversion gas inverted water gas comprising (enriched in) carbon monoxide and water (relative to the mixture of carbon dioxide flow and hydrogen flow), said inverted water gas conversion reaction unit comprising three successive zones of distinct functions: - a heating zone adapted to heat the carbon dioxide flow and / or the hydrogen flow, separately or as a mixture; - a distribution zone adapted to distribute uniformly in terms of gas velocity (uniform distribution of velocity vectors over the flow surface of the reactor) a heated mixture comprising a flow of heated carbon dioxide and a flow of heated hydrogen, in / towards a reaction zone; and - the reaction zone comprising at least one catalytic bed adapted to convert at least in part the carbon dioxide and the hydrogen into carbon monoxide and into water to produce the reverse water gas conversion gas.

[0008] According to one or more embodiments, the distribution zone is adapted to mix the carbon dioxide with the hydrogen stream to produce the heated mixture, and send the heated mixture into the reaction zone.

[0009] According to one or more embodiments, the heating zone is adapted to heat a stream comprising CO before or after being mixed with the stream of carbon dioxide and / or the stream of hydrogen, or the distribution zone is adapted to mix the stream comprising CO with the stream of carbon dioxide and / or the stream of hydrogen or directly with the heated mixture.

[0010] According to one or more embodiments, the distribution zone comprises at least one first chamber whose lower part is cylindrical with a height Hl and a diameter Dl containing at least one internal adapted to standardize the speeds of the gases before entering the reaction zone, the gases circulating with a speed Ul.

[0011] According to one or more embodiments, the first chamber of the distribution zone is characterized by: - Hl / D-1 between 0.6 and 2.0, preferably between 1.0 and 1.6; - the presence of a layer of inert solid particles having a minimum fluidization speed Umf (predetermined), the maximum gas speed at the surface of the layer of inert solid particles Umax being less than Umf.

[0012] According to one or more embodiments, the first chamber of the distribution zone is adapted so that: - Ul is between 1.0 m / s and 5.5 m / s, preferably between 3 m / s and 5 m / s.

[0013] According to one or more embodiments, the first chamber comprises an upper part of conical section to adapt a diameter Da-1 of admission of the flows to the diameter Dl of the lower part of the first chamber, Da-1 being smaller than Dl, the cone is characterized by an angle a between 30° and 80°, preferably between 40° and 70° relative to the Z direction of flow circulation (e.g. vertical).

[0014] According to one or more embodiments, the distribution zone provides a mixing function and comprises a second chamber whose lower part is substantially cylindrical with a height H-2 and a diameter D-2, the second chamber being located (directly) upstream of the first chamber, the carbon dioxide and hydrogen flows entering the upper part of the second chamber in separate intake tubes with diameters D-3 and D-4, respectively, the CO2 flow circulating with a speed U-3, the hydrogen flow circulating with a speed U-4.

[0015] According to one or more embodiments, the distribution zone is characterized by: - Hl / D-1 between 0.6 and 2.0, preferably between 1.0 and 1.6; - H-2 / D-2 between 2.4 and 10, preferably between 4 and 8; - Dl / D-2 between 2.5 and 8.0, preferably between 2.5 and 5.0; - D-3 / D-4 between 0.4 and 1.2, preferably between 0.6 and 1.1; - the presence of a layer of inert solid particles having a minimum fluidization speed Umf, the maximum gas speed at the surface of the layer of inert solid particles Umax being less than Umf.

[0016] According to one or more embodiments, the distribution zone is adapted so that: - Ul is between 1.0 m / s and 5.5 m / s, preferably between 3 m / s and 5 m / s; - U-3 is between 10 m / s and 60 m / s, preferably between 15 m / s and 55 m / s; - U-4 is between 20 m / s and 120 m / s, preferably between 40 m / s and 100 m / s.

[0017] According to one or more embodiments, the intake tubes of the carbon dioxide flow and the hydrogen flow are inclined relative to the direction Z of circulation of the flows.

[0018] According to a second aspect, the aforementioned objects, as well as other advantages, are obtained by a method for producing gas from the conversion of gas to inverted water by conversion of a feedstock containing carbon dioxide, implementing a device comprising the following elements: - a reverse water gas conversion reaction unit adapted to treat a carbon dioxide stream with a hydrogen stream, and produce a reverse water gas conversion gas comprising carbon monoxide and water, said reverse water gas conversion reaction unit comprising three successive zones of distinct functions: - a heating zone;

[0019] - a distribution area; and - a reaction zone comprising at least one catalytic bed, the method comprising the following steps: - heating the carbon dioxide stream and / or the hydrogen stream separately or in a mixture in the heating zone; - standardize in terms of gas velocity (uniform distribution of velocity vectors over the flow surface of the reactor) a mixture comprising the flow of heated carbon dioxide and the flow of heated hydrogen in the distribution zone; - distributing the mixture comprising the heated carbon dioxide stream and the heated hydrogen stream to / into the reaction zone; and - converting at least partially the carbon dioxide and hydrogen into carbon monoxide and water in the reaction zone to produce the reverse water gas conversion gas.

[0020] According to one or more embodiments, comprising one of the following steps: - heating the carbon dioxide stream and / or the hydrogen stream in the heating zone to produce: a heated carbon dioxide stream with a target temperature greater than or equal to 810°C, preferably greater than or equal to 910°C, preferably greater than or equal to 960°C (e.g. greater than or equal to 1000°C), and / or a heated hydrogen stream with a target temperature greater than or equal to 810°C, preferably greater than or equal to 910°C, preferably greater than or equal to 960°C (e.g. greater than or equal to 1000°C), with the condition that the carbon dioxide stream and the hydrogen stream are heated separately; or - heating a preheated mixture of carbon dioxide stream and hydrogen stream in the heating zone to produce a heated mixture with a target temperature greater than or equal to 810°C, preferably greater than or equal to 910°C, preferably greater than or equal to 960°C (eg greater than or equal to 1000°C), with the condition that the temperature of the preheated mixture is at least 700°C;

[0021] According to one or more embodiments, the preheated mixture of carbon dioxide stream and hydrogen stream is heated in the heating zone, the temperature of the preheated mixture is greater than or equal to 810°C, and a heated mixture is produced with a target temperature greater than or equal to 910°C, preferably greater than or equal to 960°C (eg greater than or equal to 1000°C).

[0022] According to one or more embodiments, the temperature of the carbon dioxide stream is between 700°C and 900°C, preferably between 760°C and 860°C. According to one or more embodiments, the temperature of the carbon dioxide stream is greater than or equal to 800°C.

[0023] According to one or more embodiments, the temperature of the hydrogen flow is between 700°C and 900°C, preferably between 760°C and 860°C. According to one or more embodiments, the temperature of the hydrogen flow is greater than or equal to 800°C.

[0024] According to one or more embodiments, the temperature of the carbon dioxide stream is between 700°C and 900°C, preferably between 760°C and 860°C, and / or the temperature of the hydrogen stream is between 700°C and 900°C, preferably between 760°C and 860°C.

[0025] According to one or more embodiments, the method comprises: - separately heating a carbon dioxide source and / or a hydrogen source by heat exchange with the reverse water gas conversion gas in a heat exchange section to produce the preheated carbon dioxide stream of target temperature greater than or equal to 300°C, preferably greater than or equal to 400°C preferably greater than or equal to 500°C preferably greater than or equal to 600°C, preferably greater than or equal to 700°C, preferably greater than or equal to 750°C, and / or a preheated hydrogen stream of target temperature greater than or equal to 300°C, preferably greater than or equal to 400°C preferably greater than or equal to 500°C preferably greater than or equal to 600°C, preferably greater than or equal to 700°C, preferably greater than or equal to 750°C.

[0026] According to one or more embodiments, the heating zone is adapted to mix the carbon dioxide stream with the hydrogen stream to produce the preheated mixture with a temperature of at least 700°C and preferably with a temperature of at least 800°C.

[0027] According to one or more embodiments, the initial temperature of the carbon dioxide source is less than 300°C, preferably less than 250°C, preferably less than 200°C, and / or the initial temperature of the hydrogen source is less than 300°C, preferably less than 200°C, preferably less than 150°C.

[0028] According to one or more embodiments, the reaction zone is suitable for use under the following operating conditions: - space velocity of the gas at the reactor inlet between 2000 NL / kgcata / h and 40000 NL / kgcata / h; - catalyst based on the elements Ni, Cu, Fe, Co or precious metals such as Pt, Pd, Ru, Ag and Au. According to one or more embodiments, the catalyst for the RWGS reaction comprises a support, for example based on alumina, silica, silica-alumina, alumina-silica.

[0029] According to one or more embodiments, the catalyst has a ring or cylinder shape. Advantageously, the RWGS reaction unit comprises a catalytic bed allowing a carbon dioxide conversion of at least 60%, preferably at least 65%, preferably at least 67%.

[0030] According to one or more embodiments, the heating zone, the distribution zone and / or the reaction zone are adapted to be used at a pressure between 0.1 MPa and 10 MPa, preferably between 0.1 MPa and 5 MPa, and more preferably between 0.1 MPa and 3.5 MPa.

[0031] According to one or more embodiments, electricity is used to provide the calories required by the reverse water gas conversion reaction unit.

[0032] Embodiments of the device and the method according to the aforementioned aspects as well as other characteristics and advantages will appear on reading the description which follows, given solely for illustrative and non-limiting purposes, and with reference to the following drawings. List of figures

[0033] [Fig.l] shows a schematic representation of a device according to the present invention, comprising a heating zone A, a distribution zone B and a reaction zone C.

[0034] [Fig.2] shows a schematic representation of the device of [Fig.l] comprising a heat exchange section 3.

[0035] [Fig.3] shows a schematic representation of the device according to [Fig.2], in which the heating zone A comprises 2 separate heating sections A1 and A2.

[0036] [Fig.4] shows a schematic representation of the device according to [Fig.2] adapted to treat a flow comprising CO 9.

[0037] [Fig.5] shows a schematic representation of the device according to [Fig.3] adapted to treat a flow comprising CO 9.

[0038] [Fig.6] shows a schematic representation of a distribution zone B of a device according to the present invention. Description of the embodiments

[0039] Embodiments of the device according to the first aspect and the method according to the second aspect will now be described in detail. In the following detailed description, numerous specific details are set forth in order to provide a more thorough understanding of the device and the method. However, it will be apparent to those skilled in the art that the device and the method can be implemented without these specific details. In other cases, well-known features have not been described in detail to avoid unnecessarily complicating the description.

[0040] In the present description, the term "comprise" is synonymous with (means the same as) "include" and "contain", and is inclusive or open and does not exclude other elements not recited. It is understood that the term "comprise" includes the exclusive and closed term "consist". Furthermore, in the present description, an effluent comprising essentially or solely a compound A corresponds to an effluent comprising at least 95% by weight, preferably at least 98% by weight, very preferably at least 99% by weight, of compound A. In the present description, gas velocity means the superficial gas velocity.

[0041] The present invention can be defined as a device and a method comprising a sequence of elements or operations making it possible to produce synthesis gas, composed mainly of carbon monoxide (CO), by conversion of carbon dioxide (CO2) in the presence of hydrogen (H2). In particular, the method and the device for producing synthesis gas from carbon dioxide and hydrogen make it possible to guarantee the quality of the synthesis gas produced. The method and the device according to the invention make it possible in particular to reduce the quantity of methane present in the synthesis gas.

[0042] The device and the method according to the invention are notably characterized in that they comprise and use a reverse water gas conversion unit (RWGS) and optionally one or more load / effluent heat exchanger trains.

[0043] The necessary carbon dioxide can be provided by a unit for separating a flow comprising carbon dioxide (e.g. combustion fumes) or a unit for capturing carbon dioxide (e.g. carbon dioxide present in the air).

[0044] The hydrogen required for the conversion of carbon dioxide can be produced by a water electrolysis unit, said water being able to come from the effluent of the RWGS reaction unit and optionally from downstream units (for example Fischer-Tropsch (FT) or alcohol synthesis units). Preferably, the use of the water electrolysis unit to treat the water produced by the RWGS reaction unit also makes it possible to minimize the environmental impact of the process. Thus, the process according to the invention does not require an external supply of hydrogen, for example produced by steam reforming of natural gas. The electrolyzer can preferably operate with low-carbon electricity (such as solar or wind for example or even nuclear), which contributes to a low environmental impact of the synthesis gas and the hydrocarbons which will then be produced from this synthesis gas.Furthermore, the water used for hydrogen production can come at least in part from the recycling of water produced by the RWGS reaction, which has the advantage of limiting the external water supply.

[0045] With reference to [Fig. 1], according to the first aspect and the second aspect, the device and method for producing synthesis gas according to the present invention comprises / uses a reverse water gas conversion reaction unit 6 (RWGS reaction unit) adapted to treat a carbon dioxide stream 4 with a hydrogen stream 5, and produce a RWGS gas 7 comprising carbon monoxide and water, and in particular enriched in carbon monoxide and water with respect to the mixture of carbon dioxide stream 4 and hydrogen stream 5, said reverse gas-to-water conversion reaction unit 6 comprising three successive zones with distinct functions: - a heating zone A adapted to heat the carbon dioxide flow (4) and / or the hydrogen flow (5), separately or as a mixture; - a distribution zone B, adapted to distribute uniformly in terms of gas velocity (uniform distribution of the velocity vectors over the flow surface of the reactor) a mixture comprising the flow of heated carbon dioxide and the flow of heated hydrogen, in a reaction zone C; and - the reaction zone C comprising at least one catalytic bed adapted to convert at least in part the carbon dioxide and the hydrogen into carbon monoxide and water.

[0046] The applicant has found that distribution zone B makes it possible to avoid fluidizing the catalyst of the catalytic bed of the reaction zone and to improve the conversion by ensuring a homogeneous distribution in terms of concentration.

[0047] According to one or more embodiments, the heating zone A is adapted, during the process, to: - heating a carbon dioxide stream 4 and / or a hydrogen stream 5 to produce a heated carbon dioxide stream with a target temperature greater than or equal to 810°C, preferably greater than or equal to 910°C, preferably greater than or equal to 960°C (e.g. greater than or equal to 1000°C), and / or a heated hydrogen stream with a target temperature greater than or equal to 810°C, preferably greater than or equal to 910°C, preferably greater than or equal to 960°C (e.g. greater than or equal to 1000°C), with the condition that the carbon dioxide stream 4 and the hydrogen stream 5 are heated separately; or - heating a preheated mixture of carbon dioxide stream 4 and hydrogen stream 5 to produce a heated mixture with a target temperature greater than or equal to 810°C, preferably greater than or equal to 910°C, preferably greater than or equal to 960°C (e.g. greater than or equal to 1000°C), with the condition that the temperature of the preheated mixture (i.e., before heating by the heating zone A) is at least 700°C. Preferably, when the preheated mixture of carbon dioxide stream 4 and hydrogen stream 5 is heated in the heating zone A, the temperature of the preheated mixture is greater than or equal to 810°C, and a heated mixture with a target temperature greater than or equal to 910°C, preferably greater than or equal to 960°C (e.g. greater than or equal to 1000°C) is produced.

[0048] Advantageously, when heating a mixture comprising carbon dioxide and hydrogen, methane formation occurs, the formation of methane being favored by temperatures below 700°C and being catalyzed by the nickel present in high-temperature resistant metallurgies. In addition, the presence of methane in the temperature range between 400 and 800°C induces the phenomenon of corrosion by metal dusting, degradation of metal alloys, for example based on iron or nickel, into metal dust. In particular, metal dusting is a significant local loss of thickness, generalized or in the form of pitting which, due to the diffusion of carbon in the metal, leads to the decomposition of the metal by the formation on the surface of metal particles (dust) and carbides or coke.

[0049] According to one or more embodiments, electricity, for example low carbon (such as solar or wind for example or even nuclear), is used to provide the calories necessary for the RWGS reaction unit 6, for example to the heating zone A.The supply of calories can be carried out by means of electrical resistors located in the zone(s) requiring a supply of calories. Advantageously, the electrical resistors can be in direct contact or without contact with the flow(s) circulating in the zone(s). The metallurgy of the zones considered can be adapted to the nature and temperature of the gas flow passing through said zones.

[0050] According to one or more embodiments, the temperature of the carbon dioxide stream 4 (at the inlet of the RWGS reaction unit 6) is between 700°C and 900°C, preferably between 760°C and 860°C. According to one or more embodiments, the temperature of the carbon dioxide stream 4 (at the inlet of the RWGS reaction unit 6) is greater than or equal to 800°C.

[0051] According to one or more embodiments, the temperature of the hydrogen stream 5 (at the inlet of the RWGS reaction unit 6) is between 700°C and 900°C, preferably between 760°C and 860°C. According to one or more embodiments, the temperature of the hydrogen stream 5 (at the inlet of the RWGS reaction unit 6) is greater than or equal to 800°C.

[0052] Furthermore, the heating zone A may optionally have the additional function of ensuring the mixing of the reactants, i.e. the mixing of a carbon dioxide stream 4 with a hydrogen stream 5, in order to homogenize the concentrations. According to one or more embodiments, the heating zone A is adapted to mix the carbon dioxide stream 4 with the hydrogen stream 5 to produce the preheated mixture with a temperature of at least 700°C and preferably with a temperature of at least 800°C, the carbon dioxide stream 4 and the hydrogen stream 5 being preheated separately.

[0053] According to one or more embodiments, the target temperature of the heated carbon dioxide stream is between 810°C and 1100°C, preferably between 880°C and 1050°C, preferably between 930°C and 1050°C, preferably between 960°C and 1050°C or between 980°C and 1050°C.

[0054] According to one or more embodiments, the target temperature of the heated hydrogen stream is between 810°C and 1100°C, preferably between 880°C and 1050°C, preferably between 930°C and 1050°C, preferably between 960°C and 1050°C or between 980°C and 1050°C.

[0055] According to one or more embodiments, the target temperature of the heated mixture is between 810°C and 1200°C, preferably between 910°C and 1100°C, preferably between 960°C and 1050°C or between 980°C and 1050°C.

[0056] With reference to [Fig.2], according to one or more embodiments, the synthesis gas production device according to the present invention comprises an optional heat exchange section 3 adapted to separately heat a carbon dioxide source 1 and / or a hydrogen source 2 by heat exchange with a reverse water gas shift gas 7 (RWGS gas), and produce the preheated carbon dioxide stream 4 of target temperature greater than or equal to 300°C, preferably greater than or equal to 400°C preferably greater than or equal to 500°C preferably greater than or equal to 600°C, preferably greater than or equal to 700°C, preferably greater than or equal to 750°C, and / or a preheated hydrogen stream 5 of target temperature greater than or equal to 300°C, preferably greater than or equal to 400°C preferably greater than or equal to 500°C preferably greater than or equal to 600°C, preferably greater than or equal to equal to 700°C, preferably greater than or equal to 750°C.Preferably, the heat exchange section 3 is arranged directly downstream (e.g. at the outlet of) the RWGS reaction unit 6.

[0057] According to one or more embodiments, the initial temperature (eg at the inlet of the heat exchange section 3) of the carbon dioxide source 1 is less than 300°C, preferably less than 250°C, preferably less than 200°C. According to one or more embodiments, the initial temperature of the carbon dioxide source 1 is between -50°C and 300°C, preferably between 0°C and 250°C, preferably between 0°C and 200°C.

[0058] According to one or more embodiments, the initial temperature (eg at the inlet of the heat exchange section 3) of the hydrogen source 2 is less than 300°C, preferably less than 200°C, preferably less than 150°C. According to one or more embodiments, the initial temperature of the hydrogen source 2 is between 10°C and 300°C, preferably between 10°C and 200°C, preferably between 10°C and 150°C.

[0059] According to one or more embodiments, the optional heat exchange section 3 comprises one or more heat exchangers (e.g. train of heat exchangers) adapted to separately heat each of the flows by heat exchange with the RWGS gas 7, for example directly at the outlet of the reaction unit. of RWGS 6, and produce a cooled RWGS gas 8. According to one or more embodiments, the at least one heat exchanger is adapted to heat in parallel the carbon dioxide source 1 and the hydrogen source 2. For example, the RWGS gas 7 can be divided into two streams, one heating the carbon dioxide source 1 by means of one or more heat exchangers, the other heating the hydrogen source 2 by means of another or other heat exchangers. According to one or more embodiments, the at least one heat exchanger comprises at least one multi-service heat exchanger, i.e. heat exchanger adapted to heat in parallel at least two distinct fluids.According to one or more embodiments, the at least one heat exchanger is adapted to heat in series the carbon dioxide source 1 and the hydrogen source 2, for example, the RWGS gas 7 heats the carbon dioxide source 1 and then the hydrogen source 2, or the hydrogen source 2 and then the carbon dioxide source 1, by means of one or more heat exchangers. According to one or more embodiments, the at least one heat exchanger comprises at least one plate or shell and tube heat exchanger.

[0060] According to one or more embodiments, the RWGS gas 7 has an outlet temperature from the RWGS reaction unit 6 (e.g. lower than the target temperature of the heated mixture comprising the carbon dioxide stream and the hydrogen stream) of at least 700°C, preferably at least 750°C, very preferably at least 800°C, for example a temperature between 800°C and 1050°C, preferably a temperature between 800°C and 1000°C, preferably a temperature between 800°C and 900°C. According to one or more embodiments, the temperature difference between the heated mixture on the one hand and the RWGS 7 gas on the other hand is at least 10°C, preferably at least 40°C, very preferably at least 50°C, for example a temperature difference of between 50°C and 200°C, preferably a temperature difference of between 60°C and 195°C, preferably a temperature difference of between 80°C and 190°C.It is understood that the temperature of the inlet gas in the reaction unit of RWGS 6 is higher than that of the gas of RWGS 7. .

[0061] It is understood in the present application that, although it is preferable that the carbon dioxide source 1 and / or the hydrogen source 2 are preheated by the RWGS gas 7 produced by the RWGS reaction unit 6, the preheating of the carbon dioxide source 1 and / or the hydrogen source 2 may be carried out by any means known to those skilled in the art. For example, according to one or more embodiments, the synthesis gas production device according to the present invention comprises at least one heating system such as a furnace (not described in the figures) adapted to separately heat the carbon dioxide source 1 and / or the hydrogen source 2, and produce the preheated carbon dioxide stream 4 with a target temperature greater than or equal to 700°C, preferably greater than or equal to 750°C, and / or the preheated hydrogen stream 5 with a target temperature greater than or equal to 700°C, preferably greater than or equal to 750°C. Preferably, the heating system is arranged directly upstream (e.g. at the inlet of) the RWGS reaction unit 6.

[0062] According to one or more embodiments, the heating system is powered at least in part by electrical energy. According to one or more embodiments, the heating system is powered at least in part by a fuel. According to one or more embodiments, the heating system is powered in a hybrid manner by electrical energy and by a fuel. Preferably, the heating system is essentially or totally powered by electrical energy.

[0063] Advantageously, existing electric furnace or electric heating system technologies make it possible to reach the preheating temperatures. According to one or more embodiments, the electric heating system is (of) tubular technology, each flow to be heated circulating in one or more tubes, said tubes being able to be heated either by a system of electrical resistances or by impedance. According to one or more embodiments, the electric heating system consists of electrical resistances immersed in the flows to be heated. According to one or more embodiments, the supply of calories is carried out by impedance, each flow then circulating in one or more metal tubes.According to one or more other embodiments, the supply of calories is carried out by means of electrical resistances which can be immersed within the flows circulating in one or more tubes made of materials adapted to the chemical composition and the temperature of the flow or which can be without direct contact, the flows then circulating in a metal tube. The metallurgy of the metal tube can be adapted to the nature of the flows to be heated and to the target temperatures.

[0064] In the case of a furnace powered at least partially by a fuel, the furnace is preferably powered by a source of oxygen (air and / or oxygen produced by the electrolyser), and by at least one of the following fuels: - a gaseous hydrocarbon effluent (“off-gas” according to English terminology), such as an effluent from an FT unit treating RWGS 7 gas, or from a hydrocracking, hydrotreatment or hydroisomerization unit for paraffins produced by the FT unit, or an effluent from a methanol synthesis unit); and / or - hydrogen, for example produced by the electrolyser.

[0065] According to one or more embodiments, the hydrocarbon gaseous effluent comprises at least one of the following: unconverted RWGS 7 gas, carbon dioxide, gaseous hydrocarbons, such as Cl- paraffins C4, C2-C4 olefins, and / or C1-C3 oxygenated compounds. According to one or more embodiments, when the furnace is fed by the hydrocarbon gas effluent, the furnace is a partial oxidation unit, making it possible in particular to produce an effluent rich in carbon monoxide, and preferably composed essentially of carbon monoxide, and optionally comprising carbon dioxide, hydrogen and water.

[0066] With reference to [Fig. 3], according to one or more embodiments, the heating zone A comprises 2 distinct heating sections A1 and A2 separated from each other (i.e. without flow from one section to the other), the section A1 being adapted to increase the temperature of the carbon dioxide-rich flow 4 and the section A2 being adapted to increase the temperature of the hydrogen flow 5. According to one or more embodiments, the heating zone A is adapted to separately heat the carbon dioxide flow 4 and the hydrogen flow 5 and send (separately) the heated carbon dioxide flow 4 and the heated hydrogen flow into the distribution zone B.

[0067] The distribution zone B may optionally have the additional function of ensuring the mixing of the reactants, i.e. the heated carbon dioxide stream with the heated / preheated hydrogen stream or the heated hydrogen stream with the heated / preheated carbon dioxide stream, in order to homogenize the concentrations. According to one or more embodiments, the distribution zone B is adapted to mix the heated carbon dioxide stream with the heated hydrogen stream, produce the heated mixture, distribute said heated mixture uniformly in terms of gas velocity and send it to the reaction zone C. Advantageously, by mixing the carbon dioxide stream and the hydrogen stream thus heated / preheated to form a heated mixture with a target temperature of at least 810°C, the production of methane and metal dusting are further limited.

[0068] According to one or more embodiments, the RWGS conversion reaction unit 6 is adapted to treat a stream comprising CO 9. With reference to [Fig. 4], according to one or more embodiments, the heating zone A is adapted to heat the stream comprising CO 9 before or after mixing the stream comprising CO 9 with the carbon dioxide stream 4 and the hydrogen stream 5. Alternatively, according to one or more embodiments, the distribution zone B is adapted to mix the stream comprising CO 9 (see hatched arrow) with the heated mixture comprising the carbon dioxide stream and the hydrogen stream, then to distribute uniformly in terms of gas velocity the new heated mixture (comprising CO2, CO and H2) in the reaction zone C.

[0069] With reference to [Fig.5], according to one or more embodiments, the section A1 of the heating zone A is adapted for: - heating the stream comprising CO 9 and mixing the stream comprising CO 9 with the stream of carbon dioxide 4, or - heating the carbon dioxide 4 stream and mixing the carbon dioxide 4 stream with the stream comprising CO 9, or - mixing the carbon dioxide stream 4 with the stream comprising CO 9 and heating the CO-CO2 mixture. Alternatively, according to one or more embodiments, the distribution zone B is adapted to mix the flow comprising CO 9 (see hatched arrow) with the heated carbon dioxide flow and (then) also with the heated hydrogen flow, then to distribute uniformly in terms of gas velocity the new heated mixture (comprising CO2, CO and H2) in the reaction zone C.

[0070] According to one or more embodiments, the heating zone A is adapted so that the carbon dioxide flow 4 and / or the hydrogen flow 5 circulate with a Reynolds number greater than 3000.

[0071] With reference to [Fig.6], according to one or more embodiments, the uniform distribution in terms of gas velocity of the heated mixture in the distribution zone B is obtained by a first chamber B1 whose lower part (downstream part relative to the direction of circulation of the heated mixture) is substantially cylindrical with a height H1 and a diameter D1 containing at least one internal element adapted to standardize the gas velocities before entering the reaction zone C, such as, for example, at least one layer of inert solid particles ("grading" according to English terminology) such as ceramic particles, and / or elements, for example packing elements. The superficial velocity of the gases in the first chamber B1 is Ul.Preferably, in the case where at least one “grading” layer is used, the maximum gas velocity at the surface of the “grading” Umax is lower than the minimum fluidization velocity of the “grading” Umf (Umf being a characteristic of the grading known to those skilled in the art). According to one or more embodiments, the distribution zone B is characterized by: . - Hl between 0.1 m and 20 m, preferably between 0.5 m and 13 m; - Dl between 0.2 m and 10 m, preferably between 0.5 m and 8 m; - Hl / D-1 between 0.6 and 2.0, preferably between 1.0 and 1.6; - Ul between 1.0 m / s and 5.5 m / s, preferably between 3 m / s and 5 m / s; - Umax / Umf is less than 1.

[0072] Optionally, the first chamber B1 comprises an upper part (upstream part relative to the direction of circulation of the heated mixture coming from the heating zone A) of conical section to adapt a (smaller) diameter Da-1 admission of the flows to a (larger) diameter Dl of the lower part of the first chamber Bl. Preferably, the cone is characterized by an angle a between 30° and 80°, preferably between 40° and 70° (relative to the direction of circulation of the heated mixture, i.e., substantially relative to the vertical).

[0073] According to one or more embodiments, in the case where the distribution zone B provides a function of mixing the reactants, it comprises a second chamber B2 of height H-2 and diameter D-2 of which at least the lower part (downstream part relative to the direction of circulation of the flows to be mixed coming from the heating zone A) is substantially cylindrical (of diameter D-2), the second chamber B2 being located (directly) upstream of the first chamber B1. The flow of heated / preheated carbon dioxide and the flow of heated / preheated hydrogen enter the upper part (upstream part relative to the direction of circulation of the flows to be mixed) of the second chamber B2 in separate inlet tubes B3 and B4 of diameter D-3 and D-4, respectively, the flow of CO2 circulating with a superficial velocity U-3, the flow of hydrogen circulating with a superficial velocity U-4.According to one or more embodiments, the diameter D-2 corresponds to the diameter Da-1. According to one or more embodiments, the upper part of the chamber B2 is adapted to ensure the connection with the intake tubes B3 and B4 of the carbon dioxide flow and the hydrogen flow. According to one or more embodiments, the intake tubes B3 and B4 of the carbon dioxide flow and the hydrogen flow are inclined relative to the direction Z of circulation of the flows, preferably at an angle [3 between 10° to 90°, preferably between 20 to 60°, relative to the direction Z of circulation of the flows.

[0074] According to one or more embodiments, the distribution zone B is characterized by: - Hl between 0.1 m and 20 m, preferably between 0.5 m and 13 m; - Dl between 0.2 m and 10 m, preferably between 0.5 m and 8 m; - H-2 between 0.05 m and 30 m, preferably between 0.4 m and 18 m; - D-2 between 0.04 m and 4 m, preferably between 0.1 m and 3 m; - D-3 between 0.04 m and 1.9 m, preferably between 0.05 m and 1.3 m; - D-4 between 0.04 m and 1.6 m, preferably between 0.05 m and 1.2 m; - Hl / D-1 between 0.6 and 2.0, preferably between 1.0 and 1.6; - H-2 / D-2 between 2.4 and 8, preferably between 4 and 6; - Dl / D-2 between 2.5 and 8.0, preferably between 2.5 and 5.0; - D-3 / D-4 between 0.4 and 1.2, preferably between 0.6 and 1.1; - U-3 between 10 m / s and 60 m / s, preferably between 15 m / s and 55 m / s; - U-4 between 20 m / s and 120 m / s, preferably between 40 m / s and 100 m / s; - Ul between 1.0 m / s and 5.5 m / s, preferably between 3 m / s and 5 m / s; - Umax / Umf less than 1.

[0075] Advantageously, the standardization of the gas velocities makes it possible to avoid fluidizing the catalyst of the catalytic bed of the reaction zone C while ensuring a homogeneous distribution of the gas and concentration velocities. The standardization of the gas velocity field is characterized by a uniformity index IU-v greater than 95%, preferably greater than 97%, preferably greater than 98%. The homogenization of the concentration is characterized by a uniformity index IU-c greater than 95%, preferably greater than 97%, preferably greater than 98%, preferably greater than 99%.

[0076] According to one or more embodiments, the reaction zone C is suitable for use under the following operating conditions: - space velocity of the gas at the reactor inlet between 2000 NL / kgcata / h and 40000 NL / kgcata / h; - catalyst based on the elements Ni, Cu, Fe, Co or precious metals such as Pt, Pd, Ru, Ag and Au. According to one or more embodiments, the catalyst for the RWGS reaction comprises a support, for example based on alumina, silica, silica-alumina, alumina-silica. According to one or more embodiments, the catalyst has a ring or cylinder shape. Advantageously, the RWGS reaction unit 6 comprises a catalytic bed allowing a carbon dioxide conversion of at least 60%, preferably at least 65%, preferably at least 67%.

[0077] According to one or more embodiments, the heating zone A, the distribution zone B and / or the reaction zone C are suitable for use at a pressure between 0.1 MPa and 10 MPa, preferably between 0.1 MPa and 5 MPa, and more preferably between 0.1 MPa and 3.5 MPa.

[0078] According to one or more embodiments, the heating zone A, the distribution zone B and / or the reaction zone C form an adiabatic reactor. Advantageously, the low heat loss or even the absence of heat loss in the adiabatic reactor is ensured by any means of thermal insulation known to those skilled in the art. For example, the insulation of the adiabatic reactor can be carried out from the outside of the metal wall of the adiabatic reactor, and in this case, the metal wall is in a metallurgy resistant to temperature and gases containing CO, hydrogen and water, possibly covered with a coating (e.g. layer < 1 mm) against coking and metal dusting (e.g. coating based on Al, Cr or Si which is then oxidized in situ to form a layer of Al2O3 oxide).For example, the insulation of the adiabatic reactor can be done from the inside of the metal wall of the adiabatic reactor, with one or more layers of insulating materials.

[0079] According to one or more embodiments, the amount of hydrogen at the inlet of the RWGS reaction unit 6 is adjusted so that the H2 / CO molar ratio at the outlet of the RWGS reaction unit 6 is compatible with the need for a downstream FT unit (not described in the figures) or an alcohol synthesis unit (not described in the figures). According to one or more embodiments, the amount of hydrogen at the inlet of the RWGS reaction unit 6 is controlled so that the H2 / CO molar ratio in the RWGS gas 7 at the outlet of the RWGS reaction unit 6 is between 0.5 and 4, preferably between 1 and 3, more preferably between 1.5 and 2.5.

[0080] According to one or more embodiments, a portion of the hydrogen required for the FT synthesis or the synthesis of alcohols may be supplied downstream of the RWGS reaction unit 6, for example by mixing a source of make-up hydrogen with the RWGS gas 7 or the cooled RWGS gas 8, respectively upstream or downstream of the heat exchange section 3. For example, the addition of hydrogen may be made downstream of a water separation unit (defined below) adapted to separate water contained in the RWGS gas 7 or the cooled RWGS gas 8. Preferably, the addition of hydrogen is made upstream of the reaction unit which produces paraffinic hydrocarbons (FT synthesis) or alcohols.

[0081] According to one or more embodiments, the RWGS gas 7 or the cooled RWGS gas 8, and preferably the cooled RWGS gas 8, is sent into the water separation unit (not described in the figures), to separate at least partially or completely the water present in the RWGS gas and produce a water-depleted RWGS gas. Advantageously, the water-depleted RWGS gas essentially comprises carbon monoxide, optionally carbon dioxide (residual) and optionally hydrogen (when hydrogen is in excess). For example, the RWGS gas can be cooled to a condensation temperature allowing condensation and the water present in the RWGS gas.

[0082] According to one or more embodiments, the water electrolysis unit (not described in the figures) treats at least in part the water separated from the water-depleted RWGS gas and / or separated from an effluent from a downstream unit (e.g. for the production of paraffinic hydrocarbons or alcohols) to produce at least in part the hydrogen source 2. The water electrolysis unit may optionally treat in part or completely water coming from a make-up line.

[0083] According to one or more embodiments, the water electrolysis unit comprises at least one alkaline type electrolyzer. Other electrolyzer technologies may be used for the water electrolysis unit, such as proton exchange membrane electrolysis (PEM for "Proton Exchange Membrane" according to English terminology), solid oxide electrolysis (SOE for " Solid Oxide Electrolysis (SOE) or anion exchange membrane electrolysis (AEM). The operating conditions (temperature, pressure, nature of the electrolyte, electrodes and diaphragm / membrane) are then specific to each technology.

[0084] According to one or more embodiments, the water electrolysis unit comprises at least one reactor used in at least one of the following operating conditions: Alkaline type electrolyzer: - temperature between 60°C and 90°C, - pressure between 0.1 MPa and 20 MPa, preferably between 0.1 MPa and 4 MPa, - electrolyte comprising KOH, - electrodes comprising a metal alloy, - diaphragm comprising asbestos, polytetrafluoroethylene and / or nickel oxide; Proton exchange membrane (PEM) electrolyzer: - temperature between 50°C and 80°C, - pressure between 0.1 MPa and 20 MPa, preferably between 1.8 MPa and 5.5 MPa, - electrolyte comprising a polymer membrane, - electrodes comprising a metal alloy; Solid Oxide Electrolyzer (SOE): - temperature between 800°C and 900°C, - pressure between 0.1 MPa and 2 MPa, preferably between 0.1 MPa and 0.5 MPa, - electrolyte comprising a ceramic membrane (eg perovskite type), - electrodes comprising a metal alloy; Anion exchange membrane (AEM) type electrolyzer: - temperature between 50°C and 70°C, - pressure between 0.1 MPa and 20 MPa, preferably between 0.1 MPa and 3.5 MPa, - electrolyte comprising a polymer membrane, - electrodes comprising a metal alloy.

[0085] According to one or more embodiments, the hydrogen source 2 produced by the water electrolysis unit comprises between 99.5% by weight and 99.999% by weight of hydrogen (after drying).

[0086] According to one or more embodiments, the carbon dioxide source 1 is purified before being introduced into the RWGS reaction unit 6. According to one or more embodiments, the carbon dioxide source 1 is purified in the heat exchange section 3. The carbon dioxide source 1 may also be purified before or after being introduced into the heat exchange section 3. On the other hand When a furnace is used, it is preferable that the carbon dioxide source 1 be purified before being introduced into the furnace.

[0087] According to one or more embodiments, the RWGS 7 gas is purified before being introduced into the reaction unit for the synthesis of paraffinic hydrocarbons or alcohols, for example upstream or downstream of the water separation unit arranged between the RWGS 6 reaction unit and said reaction unit for the synthesis of paraffinic hydrocarbons or alcohols. According to one or more embodiments, the water effluent recovered by separation on the RWGS 7 gas is purified before being introduced into the water electrolysis unit.

[0088] The effluent purification steps aim to eliminate at least partially the sulfur compounds, nitrogen compounds, halogens, heavy metals and transition metals. The main gas purification technologies are: adsorption, absorption, catalytic reactions. Examples

[0089] Examples 1A to 1E of Table 1 below are examples of a synthesis gas production device according to the present invention, comprising a reverse water gas conversion reaction unit (6) comprising three successive zones of distinct functions:

[0090] - a heating zone (A) of the preheated carbon dioxide flow (4) and of the flow preheated hydrogen (5) to produce a mixture comprising carbon dioxide and hydrogen heated to a temperature of 1000°C; - a distribution zone (B), adapted to distribute said mixture uniformly in terms of gas velocity in a reaction zone (C); and - the reaction zone (C) comprising a catalytic bed adapted to convert at least in part the carbon dioxide and hydrogen into carbon monoxide and water.

[0091] In particular, Examples F, G, and H of Table 1 are presented to show examples of distribution zone B parameters that allow for improved gas velocity uniformization criteria.

[0092] - Example 1D: example IA with the presence of “grading”, improving gas velocity uniformization; - Example 1E: example IB with “grading”, improving gas velocity uniformity; - 1D examples: IC example with Hl / D-1 in a preferred range, reducing fluidization problems of grading;

[0093] [Tables 1] Example IA IB IC 1D 1E Q (m3 / h) 45000 135000 45000 45000 135000 Ul (m / s) 4.0 4.0 4.0 4.0 4.0 Hl / D-1 1.00 0.89 0.50 1.00 0.89 Grading NO NO YES YES YES Umax / Umf N / AN / A 1.03 0.87 0.75 IU-v (%) 88.7 92.2 98.8 99.3 99.0

[0094] Examples 2A to 2H of Table 2 below are examples of a synthesis gas production device according to the present invention, comprising a reverse water gas conversion reaction unit (6) containing three successive zones of distinct functions:

[0095] - a heating zone (A) of the preheated carbon dioxide flow (4) and of the flow of preheated hydrogen (5) to produce a stream of carbon dioxide heated to a temperature of 1000°C and a stream of hydrogen heated to a temperature of 1000°C; - a distribution zone (B), adapted to mix said stream of heated carbon dioxide with said stream of heated hydrogen and to distribute uniformly in terms of gas velocity said mixture in a reaction zone (C); and - the reaction zone (C) comprising a catalytic bed adapted to convert at least in part the carbon dioxide and the hydrogen into carbon monoxide and water.

[0096] In particular, Examples 2F, 2G, and 2H of Table 2 are presented to show examples of distribution zone B parameters that allow for improved gas velocity and concentration uniformization criteria.

[0097] - Example 2F: example 2A with the presence of “grading”, improving gas velocity standardization; - Example 2G: example 2B with “grading”, improving the uniformization of gas speed; - Example 2H: Example 2C with Hl / D-1 in a preferred range, reducing fluidization problems of grading; - Example 2F: Example 2D with H-2 / D-2 and Dl / D-2 in preferred ranges, reducing grading fluidization problems and improving gas velocity and concentration uniformity; - Example 2H: Example 2E with D-3 / D-4 in a preferred range, reducing grading fluidization problems and improving gas velocity and concentration uniformity.

[0098] [Tables2] Example 2A 2B 2C 2D 2E 2F 2G 2H Q (m3 / h) 45000 135000 45000 45000 45000 45000 135000 45000 Ul (m / s) 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 U-4 (m / s) 50 100 100 50 100 50 100 100 Hl / D-1 1.00 0.89 0.50 1.00 1.00 1.00 0.89 1.00 H-2 / D-2 4.4 4.4 4.4 1.9 4.4 4.4 4.4 4.4 Dl / D-2 3.3 3.4 3.3 1.4 3.3 3.3 3.4 3.3 D-3 / D-4 0.5 1.0 1.0 0.5 1.4 0.5 1.0 1.0 Grading NO NO YES YES YES YES YES YES Umax / Umf N / AN / A 1.03 1.50 1.06 0.87 0.75 0.87 IU-v (%) 88.7 92.2 98.8 99.1 94.7 99.3 99.0 99.6 IU-c (%) 99.1 99.0 98.6 99.2 93.4 99.5 99.1 99.5

Claims

Claims

1. A device for producing reverse water gas conversion gas by converting a feedstock containing carbon dioxide, comprising the following elements: - a reverse water gas conversion reaction unit (6) adapted to treat a carbon dioxide stream (4) with a hydrogen stream (5), and produce a reverse water gas conversion gas (7) comprising carbon monoxide and water, said reverse water gas conversion reaction unit (6) comprising three successive zones of distinct functions: - a heating zone (A) adapted to heat the carbon dioxide stream (4) and / or the hydrogen stream (5), separately or as a mixture; - a distribution zone (B) adapted to distribute uniformly in terms of gas velocity a heated mixture comprising a heated carbon dioxide stream and a hydrogen stream, to a reaction zone (C);and - the reaction zone (C) comprising at least one catalytic bed adapted to convert at least in part the carbon dioxide and the hydrogen into carbon monoxide and into water to produce the reverse water gas conversion gas (7).;

2. A device according to claim 1, wherein the distribution zone (B) is adapted to mix the carbon dioxide with the hydrogen stream to produce the heated mixture, and send the heated mixture into the reaction zone (C).

3. Device according to claim 1 or claim 2, wherein the heating zone (A) is adapted to heat a stream comprising CO (9) before or after being mixed with the stream of carbon dioxide (4) and / or the stream of hydrogen (5), or the distribution zone (B) is adapted to mix the stream comprising CO (9) with the stream of carbon dioxide and / or the stream of hydrogen or directly with the heated mixture.

4. Device according to any one of the preceding claims, in which the distribution zone (B) comprises at least one first chamber (Bl) whose lower part is cylindrical with a height H-1 and a diameter D-1 containing at least one suitable internal to standardize the gas speeds before entering the reaction zone (C), the gases circulating with a speed Ul.

5. Device according to claim 4, in which the first chamber (Bl) of the distribution zone (B) is characterized by: - ​​Hl / D-1 between 0.6 and 2.0, preferably between 1.0 and 1.6; - the presence of a layer of inert solid particles having a minimum fluidization speed Umf, the maximum gas speed at the surface of the layer of inert solid particles Umax being less than Umf.

6. Device according to claim 4 or claim 5, in which the first chamber (Bl) comprises an upper part of conical section to adapt a diameter Da-1 of admission of the flows to the diameter Dl of the lower part of the first chamber (Bl), Da-1 being smaller than Dl, the cone is characterized by an angle a of between 30° and 80°, preferably between 40° and 70° relative to the direction Z of circulation of the flows.

7. Device according to any one of claims 4 to 6, in which the distribution zone (B) provides a mixing function and comprises a second chamber (B2) whose lower part is substantially cylindrical with a height H-2 and a diameter D-2, the second chamber (B2) being located upstream of the first chamber (B1), the carbon dioxide and hydrogen flows entering the upper part of the second chamber (B2) in separate inlet tubes (B3, B4) with diameters D-3 and D-4, respectively, the CO2 flow circulating with a speed U-3, the hydrogen flow circulating with a speed U-4.

8. Device according to claim 7, in which the distribution zone (B) is characterized by: - ​​Hl / D-1 between 0.6 and 2.0, preferably between 1.0 and 1.6; - H-2 / D-2 between 2.4 and 10, preferably between 4 and 8; - Dl / D-2 between 2.5 and 8.0, preferably between 2.5 and 5.0; - D-3 / D-4 between 0.4 and 1.2, preferably between 0.6 and 1.1; - the presence of a layer of inert solid particles having a minimum fluidization speed Umf, the maximum gas speed on the surface of the layer of inert solid particles Umax being less than Umf.

9. Device according to claim 7 or claim 8, in which the intake tubes (B3, B4) of the carbon dioxide flow and the hydrogen flow are inclined relative to the direction Z of circulation of the flows.

10. A method for producing reverse water gas conversion gas by converting a feedstock containing carbon dioxide, using a device comprising the following elements: - a reverse water gas conversion reaction unit (6) adapted to treat a carbon dioxide stream (4) with a hydrogen stream (5), and produce a reverse water gas conversion gas (7) comprising carbon monoxide and water, said reverse water gas conversion reaction unit (6) comprising three successive zones with distinct functions: - a heating zone (A); - a distribution zone (B); and - a reaction zone (C) comprising at least one catalytic bed, the method comprising the following steps: - heating the carbon dioxide stream (4) and / or the hydrogen stream (5) separately or as a mixture in the heating zone (A);- uniformizing in gas velocity a mixture comprising the heated carbon dioxide stream and the heated hydrogen stream in the distribution zone (B); - distributing the mixture comprising the heated carbon dioxide stream and the heated hydrogen stream to the reaction zone (C); and - converting at least partly the carbon dioxide and hydrogen into carbon monoxide and water in the reaction zone (C) to produce the reverse water gas conversion gas (7).;

11. Method according to claim 10, comprising one of the following steps: - heating the carbon dioxide stream (4) and / or the hydrogen stream (5) in the heating zone (A) to produce: a heated carbon dioxide stream with a target temperature greater than or equal to 810°C, preferably greater than or equal to 910°C, preferably greater than or equal to 960°C, and / or a heated hydrogen stream with a target temperature greater than or equal to 810°C, preferably greater than or equal to 910°C, preferably greater than or equal to 960°C, with the condition that the carbon dioxide stream (4) and the hydrogen stream (5) are heated separately; or - heating a preheated mixture of carbon dioxide stream (4) and hydrogen stream (5) in the heating zone (A) to produce a heated mixture with a target temperature greater than or equal to 810°C, preferably greater than or equal to 910°C, preferably greater than or equal to 960°C, with the condition that the temperature of the preheated mixture is at least 700°C.

12. A method according to claim 11, wherein the preheated mixture of carbon dioxide stream (4) and hydrogen stream (5) is heated in the heating zone (A), the temperature of the preheated mixture is greater than or equal to 810°C, and a heated mixture with a target temperature greater than or equal to 910°C, preferably greater than or equal to 960°C, is produced.

13. A method according to any one of claims 10 to 12, wherein the temperature of the carbon dioxide stream (4) is between 700°C and 900°C, preferably between 760°C and 860°C, and / or the temperature of the hydrogen stream (5) is between 700°C and 900°C, preferably between 760°C and 860°C.

14. A method according to any one of claims 11 to 13, comprising: - separately heating a carbon dioxide source (1) and / or a hydrogen source (2) by heat exchange with the reverse water gas conversion gas (7) in a heat exchange section (3) to produce the preheated carbon dioxide stream (4) with a target temperature greater than or equal to 300°C, preferably greater than or equal to 400°C, preferably greater than or equal to 500°C, preferably greater than or equal to 600°C, preferably greater than or equal to 700°C, preferably greater than or equal to 750°C, and / or a preheated hydrogen stream (5) with a target temperature greater than or equal to 300°C, preferably greater than or equal to 400°C, preferably greater than or equal to 500°C, preferably greater than or equal to 600°C, preferably greater than or equal to at 700°C, preferably greater than or equal to 750°C.

15. A method according to any one of claims 11 to 14, wherein the heating zone (A) is adapted to mix the flow of carbon dioxide (4) with the hydrogen stream (5) to produce the preheated mixture of temperature of at least 700°C and preferably of temperature of at least 800°C.

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