Production of synthetic fuels from CO2 by partial oxyfuel combustion and separation of CO2 from the by-products

Abstract

The present invention relates to a device / method for capturing / converting CO2, comprising a CO2 capture unit (2) producing CO2 (3), a water electrolysis unit (5) converting water (4) to oxygen (6) and hydrogen (7), a RWGS unit (8) treating the CO2 with hydrogen to produce a CO2- and water-rich RWGS gas (9), a FT unit (13) converting the RWGS gas to produce a FT effluent (14), a first separation unit (15) treating the FT effluent to produce a hydrocarbon effluent (17) and a gaseous effluent (33), a second separation unit (34) separating the gaseous effluent into a CO2-depleted gas (18) and a CO2-rich gas (35) sent to the RWGS unit, a partial oxy-combustion unit (28) oxidizing the CO2-depleted gas to produce CO sent to the FT unit, which is sent to the RWGS unit, and a hydrogen unit (20) treating the hydrocarbon effluent to produce a hydrocarbon fraction (21).

Description

[Technical Field]

[0001] The present invention relates to the production of very high quality (essentially sulfur-, aromatics-, and nitrogen-free) synthetic fuels, i.e., gasoline, kerosene, gas oil, and / or other hydrocarbon products, such as naphtha, or lubricating oil bases. More particularly, one object of the present invention is to produce synthetic fuels from carbon dioxide (CO2) and hydrogen (H2).

[0002] The capture of carbon dioxide and its conversion to a fuel base according to the present invention involves two successive steps: the conversion of carbon dioxide and hydrogen to a synthesis gas composed primarily of CO + H, followed by the conversion of the synthesis gas to synthetic hydrocarbons via the Fischer-Tropsch (FT) process. The properties of the products from the Fischer-Tropsch process can be adjusted by appropriate post-processing operations to obtain the desired fuel specifications. [Background technology]

[0003] The use of the reverse water-gas shift (RWGS) conversion process to convert a mixture of carbon dioxide and hydrogen into synthesis gas (CO+H) has been known to those skilled in the art for a very long time. The same applies to the Fischer-Tropsch synthesis process, which allows the conversion of synthesis gas into a mixture of paraffins and / or olefins, depending on the catalyst and operating conditions. In cases where paraffins are produced, it is desirable to improve certain of their properties to enable their use in transportation applications.

[0004] An array of unit operations is the subject of a patent application, and these arrays of unit operations are aimed at converting carbon dioxide into a fuel base, often known as e-fuel.

[0005] Reference may be made, for example, to Patent Document 1, which describes a renewable Fischer-Tropsch synthesis method that allows the production of hydrocarbons and alcohols from wind energy, residual carbon dioxide, and water. The method includes the following unit operations: electrolysis of water to produce hydrogen and oxygen, a RWGS reaction to produce synthesis gas, and a Fischer-Tropsch synthesis in a high-temperature multi-tube reactor. Various recycling options are described (e.g., recycling of unconverted carbon dioxide from the RWGS after separation, recycling of ex-FT carbon dioxide to the RWGS, recycling of ex-FT unconverted H2 and CO2 to the FT).

[0006] However, the document does not mention the possibility of advantageously integrating the unit operations with the carbon dioxide capture process, nor does it mention heat integration between the various thermal energy sources generated by the unit operations.

[0007] Patent Document 2 relates to a method for producing high-octane fuels from carbon dioxide and water. The raw materials are industrial carbon dioxide and water. The final product can be high-octane gasoline, high-cetane diesel, or other liquid hydrocarbon mixtures suitable for driving conventional combustion engines or hydrocarbons suitable for further industrial processing or commercial use. Products such as dimethyl ether or methanol can be removed from the production line. The heat generated by the exothermic reaction in this method is fully utilized, as is the heat generated by the production process and the heat generated by the reprocessing of hydrocarbons not suitable for liquid fuel.

[0008] However, the '691 patent does not mention the possibility of advantageously integrating the unit operations with carbon dioxide capture processes, nor does it mention recycling from the Fischer-Tropsch reactor to maximize fuel production.

[0009] Patent Document 3 describes a method and system for producing synthesis gas by combining hydrogen and carbon monoxide from separate sources while controlling the molar ratio (H2 / CO) of the resulting synthesis gas. Hydrogen is produced by electrolysis of water. Carbon monoxide is produced by reacting carbon dioxide captured in the exhaust gas of a stationary combustion engine with hydrogen in a RWGS reactor. Hydrocarbon fuels are produced from the synthesis gas by Fischer-Tropsch synthesis.

[0010] However, the '399 patent does not mention the possibility of advantageously integrating the unit operations with carbon dioxide capture processes, nor does it mention recycling from the Fischer-Tropsch reactor to maximize fuel production.

[0011] Patent Document 4 describes a method for synthesizing hydrocarbons, which includes introducing hydrogen and carbon monoxide into a first Fischer-Tropsch reaction stage, which allows the hydrogen and carbon monoxide to partially catalytically react to form hydrocarbons. At least a portion of the tail gas containing unreacted hydrogen and carbon monoxide obtained from the first reaction stage is introduced into a second Fischer-Tropsch reaction stage, which is a two-phase high-temperature catalytic Fischer-Tropsch reaction stage. The hydrogen and carbon monoxide can be at least partially catalytically reacted in the second reaction stage to form gaseous hydrocarbons. This patent application is characterized by the presence of two Fischer-Tropsch reactors in series, with the second reactor processing unconverted synthesis gas from the first reactor. There is no carbon dioxide or water recycle.

[0012] Therefore, an analysis of the prior art shows that the operation of a series of RWGS and Fischer-Tropsch units makes it possible to produce a synthetic base for fuels from carbon dioxide and hydrogen, and in some cases the hydrogen can be produced by electrolysis of water using an electrical source, e.g., solar or wind power.

[0013] However, these documents do not provide any information regarding the possibility of integrating unit operations with carbon dioxide capture processes to provide a feedstock containing a carbon source from which fuel can be produced, with unexpectedly positive results. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] US Patent Application Publication No. 2010 / 0280135 [Patent Document 2] US Patent Application Publication No. 2007 / 0244208 [Patent Document 3] US Patent Application Publication No. 2012 / 0079767 [Patent Document 4] US Patent Application Publication No. 2007 / 0142481 Summary of the Invention [Means for solving the problem]

[0015] (Summary of the Invention) In the above context, the first objective of this specification is to overcome the problems of the prior art and to capture and upgrade carbon dioxide in the form of synthetic fuels that can be used for transportation applications.

[0016] The present invention relates to the capture and conversion of carbon dioxide to produce CO+H2 synthesis gas and the conversion of said synthesis gas to synthetic hydrocarbons by a Fischer-Tropsch reaction. The characteristics of the effluent from the Fischer-Tropsch synthesis can then be adjusted by post-treatment methods (upgrading) to make it suitable for use as land, aviation, and marine fuels. The gas produced at the outlet of the Fischer-Tropsch reactor can also be upgraded to synthetic methane (e-methane), synthetic natural gas (e-SNG), or LPG (e-LPG).

[0017] In particular, the present invention relates to a device and method for producing synthetic fuels from carbon dioxide and hydrogen, allowing for improved production of the desired product. Advantageously, the method also allows for minimizing the energy requirements for the production of said fuels through unique heat integration.

[0018] The invention is based on the presence of a partial oxyfuel combustion unit (called "POX" for partial oxidation, carried out with high purity oxygen under stoichiometric conditions to produce a H2 / CO mixture). Advantageously, the gaseous effluent is returned to the inlet of the Fischer-Tropsch reactor, allowing additional CO to be upgraded in the Fischer-Tropsch reactor.

[0019] The invention is also based on the presence of a unit for separating the carbon dioxide contained in the gaseous effluent from the Fischer-Tropsch reaction section, the carbon dioxide separated from this gaseous effluent being recycled to the inlet of the RWGS reaction unit, so that the gaseous effluent that can be sent to the partial oxyfuel combustion unit essentially no longer contains carbon dioxide.

[0020] Advantageously, the additional energy integration of the present process allows the heat release generated in the partial oxyfuel combustion unit to be used to supply thermal energy to other units of the process, such as the RWGS reaction unit and / or the carbon dioxide capture unit, thereby limiting the external supply of thermal energy required.

[0021] The energy integration of this process also allows for the generation of electricity from heat recovery: this heat, converted to electricity, can power both the water electrolysis and the RWGS reactor and / or capture unit that converts carbon dioxide and hydrogen to synthesis gas.

[0022] Advantageously, the hydrogen produced by water electrolysis can be used for carbon dioxide conversion, Fischer-Tropsch synthesis, and post-processing. Preferably, the hydrogen required in the process is provided entirely by the water electrolysis unit. Therefore, the process according to the invention does not require an external hydrogen supply, for example, produced by steam reforming of natural gas. The electrolysis cell preferably operates on low-carbon electricity, contributing to the renewable nature of the fuels and gases produced. Furthermore, the water used to produce hydrogen can come, at least in part, from recycled water produced in the various steps of the process, which has the advantage of limiting the external supply of water.

[0023] Advantageously, oxygen produced by the electrolysis of water may be fed to the partial oxy-fuel combustion section.

[0024] According to a first aspect, the above objects, as well as other advantages, are obtained by a device for capturing and converting a feedstock containing carbon dioxide, the device comprising the following units: - a unit for capturing carbon dioxide from a feedstock; for example, using at least one amine-based solvent, at least one physical solvent, for example based on polyethylene glycol dimethyl ether, and / or a physical adsorption facility operated by temperature swing adsorption; suitable for generating a carbon dioxide-rich effluent; - Water electrolysis unit; suitable for converting water to give oxygen and hydrogen; - a reverse water gas shift RWGS reaction unit; suitable for treating a carbon dioxide-rich effluent with hydrogen to produce a RWGS gas enriched with carbon monoxide and water; - a Fischer-Tropsch reaction unit, suitable for converting the RWGS gas to produce a FT effluent and, optionally, generating a first steam, for example generated by vaporizing water in an exchanger arranged inside the Fischer-Tropsch reaction unit, to supply thermal energy to a carbon dioxide capture unit; - a first separation unit; suitable for at least partially treating the FT effluent to produce: a hydrocarbon effluent, a first aqueous effluent which may be at least partially recycled to the inlet of the water electrolysis unit, and a first gaseous effluent; - a second separation unit suitable for treating the first gaseous effluent, producing a carbon dioxide-depleted gaseous effluent, optionally at least partially recycled to the Fischer-Tropsch reaction unit, and at least partially sending a carbon dioxide-rich gaseous effluent to the RWGS reaction unit; - a partial oxyfuel combustion reaction unit; suitable for partially oxidizing at least a portion of the carbon dioxide-depleted gaseous effluent; producing an oxyfuel combustion effluent containing carbon monoxide, hydrogen, carbon dioxide, and water, and passing the oxyfuel combustion effluent to a Fischer-Tropsch reaction unit; and a hydrogen reaction unit (hydrotreating and / or hydrocracking and / or hydroisomerization unit); suitable for treating the hydrocarbon effluent to give at least one hydrocarbon fraction, for example to specifications for transport applications.

[0025] According to one or more embodiments, the partial oxy-fuel combustion reaction unit is suitable for generating heat that is used to supply thermal energy (via a supply line) to the RWGS reaction unit and / or the carbon dioxide capture unit, for example by heat exchange to heat the carbon dioxide-rich effluent and / or the carbon dioxide- and / or water-rich gaseous effluent, or by integrating the reaction section of the RWGS reaction unit into the chamber of the partial oxy-fuel combustion unit.

[0026] According to one or more embodiments, a portion of the hydrogen is supplied downstream of the RWGS reaction unit and upstream of the Fischer-Tropsch reaction unit.

[0027] According to one or more embodiments, the feedstock / effluent heat exchange allows the available heat in the RWGS effluent to be used to preheat the gases (CO2 and H2 rich gases) entering the RWGS reaction unit.

[0028] According to one or more embodiments, the device comprises a first heat exchanger suitable for generating second water vapor by heat exchange between water and RWGS gas, and can be used, for example, to provide thermal energy to a carbon dioxide capture unit.

[0029] According to one or more embodiments, the device includes a first turbine for treating at least a portion of the carbon dioxide-depleted gaseous effluent separated by the first separation unit to generate electricity.

[0030] According to one or more embodiments, the second turbine is adapted to at least partially process the first steam and / or the second steam to generate electricity.

[0031] According to one or more embodiments, the electricity is used to provide thermal energy to the RWGS reaction unit and / or the carbon dioxide capture unit and / or the water electrolysis unit.

[0032] According to one or more embodiments, electricity is used to provide thermal energy to the regeneration section of the carbon dioxide capture unit.

[0033] According to one or more embodiments, the water electrolysis unit treats water from the make-up line and / or water from the RWGS gas and / or water from the FT effluent.

[0034] According to one or more embodiments, water from the RWGS gas is at least partially or substantially completely separated by a third separation unit and sent to a water electrolysis unit.

[0035] In one or more embodiments, the carbon dioxide-rich effluent and / or the carbon dioxide-rich gaseous effluent are introduced into the RWGS reaction unit, either separately or after mixing and purification. In one or more embodiments, the RWGS gas is introduced into the Fischer-Tropsch reaction unit, upstream or downstream of the third separation unit, after purification. In one or more embodiments, the first aqueous effluent is introduced into the water electrolysis unit after purification. The effluent purification process aims to at least partially remove sulfur- and nitrogen-containing compounds, halogens, heavy metals, and transition metals. The main techniques for purifying gases are adsorption, absorption, and catalytic reaction.

[0036] According to one or more embodiments, the device includes a carbon dioxide separation unit disposed between the RWGS reactor and the Fischer-Tropsch reactor, and advantageously, the size of the FT reactor (13) can therefore be reduced.

[0037] According to a second aspect, the above objectives, as well as other advantages, are obtained by a method for capturing and converting carbon dioxide, the method comprising the steps of: - treating the feedstock in a carbon dioxide capture unit; producing a carbon dioxide-rich effluent; - converting water in a water electrolysis unit to produce oxygen and hydrogen; - treating the carbon dioxide-rich effluent with hydrogen in a reverse water gas shift RWGS reaction unit; producing a RWGS gas enriched with CO and water; - converting the RWGS gas in a Fischer-Tropsch reaction unit; producing an FT effluent; - optionally generating a first steam in a Fischer-Tropsch reaction unit; and providing thermal energy to a carbon dioxide capture unit; - treating the FT effluent in a first separation unit; producing at least one hydrocarbon effluent, a first aqueous effluent, and a first gaseous effluent; treating the first gaseous effluent in a second separation unit to produce a carbon dioxide-depleted gaseous effluent and a carbon dioxide-rich gaseous effluent; the carbon dioxide-rich gaseous effluent being recycled to the inlet of the RWGS section; - partially oxidizing at least a portion of the carbon dioxide-depleted gaseous effluent in a partial oxyfuel combustion reaction unit, after optional expansion in a turbine; producing an oxyfuel combustion effluent comprising carbon monoxide and water; - passing the oxyfuel combustion effluent to a FT reaction unit; and - treating the hydrocarbon effluent in a hydrogen reaction unit; producing at least one hydrocarbon fraction, for example one meeting the specifications required for transportation applications.

[0038] According to one or more embodiments, the RWGS reaction unit comprises at least one reactor operated under at least one of the following operating conditions: the temperature is between 700°C and 1200°C, preferentially between 800°C and 1100°C, and even more preferentially between 850°C and 1050°C; - the pressure is between 0.1 MPa and 10 MPa, preferentially between 0.1 MPa and 5 MPa, more preferentially between 0.1 MPa and 3.5 MPa; - The gas space velocity is 5000 NL / kg at the reactor inlet. cata / h~40,000NL / kg cata / h; - the catalyst comprises a metal or a combination of metals selected from the group of elements consisting of Ni, Cu, Fe, Co, Pt, Pd, Ru, Ag and Au. According to one or more embodiments, the catalyst for the RWGS reaction comprises a support, for example, the support is based on alumina, silica, silica-alumina, siliceous alumina.

[0039] According to one or more embodiments, the FT reaction unit comprises at least one reactor operated under at least one of the following operating conditions: the temperature is between 170°C and 280°C, preferably between 190°C and 260°C, and preferentially between 210°C and 240°C; the absolute pressure is between 0.1 MPa and 6.0 MPa, preferably between 1.5 MPa and 3.5 MPa, preferentially between 2.0 MPa and 3.0 MPa; the catalyst comprises cobalt or iron, preferably cobalt, and optionally a support, for example based on alumina, silica, silica-alumina, siliceous alumina or titanium;

[0040] According to one or more embodiments, the partial oxyfuel combustion reaction unit comprises at least one reactor operated under at least one of the following operating conditions: the absolute pressure is between 0.1 MPa and 9 MPa, preferably between 1 MPa and 4 MPa; The temperature is between 600°C and 2000°C, preferably between 800°C and 1700°C, preferably between 1100°C and 1500°C.

[0041] According to one or more embodiments, the second separation unit is a unit for separating carbon dioxide by membrane and / or by absorption in a solvent and / or by adsorption on a solid.

[0042] Embodiments of the devices and methods according to the above aspects, as well as other features and advantages, will become apparent on reading the following description, given purely by way of non-limiting example, and with reference to the following figures, in which: DETAILED DESCRIPTION OF THE INVENTION

[0043] (List of drawings) FIG. 1 shows a schematic diagram of a device according to the invention, in which the oxyfuel combustion effluent is notably sent to a FT reaction unit.

[0044] (Description of the embodiment) Embodiments of the device according to the first aspect and the method according to the second aspect will be described in detail below. In the following detailed description, numerous specific details are disclosed to provide a deeper understanding of the device. However, it will be apparent to those skilled in the art that the device can be used without these specific details. In other cases, well-known features have not been described in detail to avoid unnecessarily complicating the description.

[0045] As used herein, the term "comprise" is synonymous with (means the same as) "include" and "contain" and is inclusive or open-ended, not excluding other elements not listed. The term "comprise" is understood to include the exclusive and closed term "consist of." Furthermore, as used herein, an effluent essentially or solely comprising compound A corresponds to an effluent comprising at least 95% by weight, preferably at least 98% by weight, and highly preferably at least 99% by weight of compound A.

[0046] As used herein, the term "physical solvent" is synonymous with (means the same thing as) a solvent that forms weak bonds (e.g., hydrogen bonds, van der Waals bonds) with a solute or that does not form strong bonds (e.g., covalent bonds, ionic bonds) with a solute.

[0047] The present invention can be defined as a device and method comprising a series of unit operations for producing synthetic hydrocarbons, such as synthetic fuels, e.g., gasoline, kerosene, gas oil and / or naphtha or lubricating oil bases, preferably of very high quality, from carbon dioxide from a capture unit.

[0048] The present devices and methods are characterized in that they include and employ, inter alia, a unit for carbon dioxide capture, a unit for reverse water-gas shift (RWGS) conversion, a unit for Fischer-Tropsch (FT) synthesis, and a unit for hydroprocessing (hydrotreating, and / or hydrocracking and / or hydroisomerization) of the hydrocarbon fraction from the FT reaction unit, a unit for separating carbon dioxide from the gaseous effluent obtained from the Fischer-Tropsch process, and a unit for partial oxy-fuel combustion of the gaseous hydrocarbon by-products of the process (RWGS and Fischer-Tropsch synthesis and post-processing) after carbon dioxide separation therefrom. Advantageously, the required hydrogen can be produced by a water electrolysis unit, and the water can be derived from the RWGS and Fischer-Tropsch reaction unit. Advantageously, the oxygen required for partial oxy-fuel combustion can be produced by electrolysis of water fed to the partial oxy-fuel combustion section and, optionally, by another unit, such as an air separation unit.

[0049] One of the features of the present invention can be summarized by the use of carbon dioxide for the production of very high quality synthetic fuels, gasoline, kerosene, gas oil and / or naphtha or lubricating oil base. The invention is particularly based on the presence of a carbon dioxide separation unit that extracts and recycles carbon dioxide from other gaseous hydrocarbon by-products of the process. The invention is also based on a partial oxyfuel combustion unit suitable for processing the carbon dioxide-depleted hydrocarbon by-products, resulting in a carbon dioxide-rich gaseous effluent and improving the production of the desired products.

[0050] Furthermore, the release of heat generated by the partial combustion can advantageously be used to supply thermal energy to the RWGS reaction unit and / or the carbon dioxide capture unit. This input of thermal energy can be done, for example, by heat exchange with: - oxyfuel combustion gases in the oxyfuel combustion chamber; and / or - Hot gaseous effluent downstream of the oxy-fuel combustion chamber; and / or - Water vapor generated by the partial oxyfuel combustion reaction unit and / or by heat exchange with the oxyfuel combustion gaseous effluent.

[0051] According to one or more embodiments, the present invention also makes it possible to minimize the amount of carbon energy external to the process, and therefore the environmental impact, by a unique energy integration based on the use of heat at the outlet of the Fischer-Tropsch reaction unit and optionally the RWGS reaction unit, to desorb carbon dioxide, e.g., complexed with an amine, in a carbon dioxide capture unit, more particularly in a solvent regeneration unit.

[0052] According to one or more embodiments, electricity can also be generated by a turbine fed by the effluent from the Fischer-Tropsch reaction unit and / or by steam (e.g. produced at the outlet of the Fischer-Tropsch reaction unit and / or the RWGS reaction unit), which makes it possible, for example, to supply thermal energy to a device according to the invention, e.g. an RWGS reaction unit.

[0053] The combination of a unit for carbon dioxide capture and chemical conversion therefore makes it possible to produce a base for fuels, in particular for the aviation sector, while minimizing the environmental impact of the process, preferably with its own heat integration.

[0054] Preferably, the use of a water electrolysis unit to treat the water produced by the RWGS reaction unit and / or the Fischer-Tropsch unit also makes it possible to minimize the environmental impact of the process.

[0055] Referring to FIG. 1, a device for converting carbon dioxide to liquid hydrocarbons comprises: a carbon dioxide capture unit (2) suitable for treating a carbon dioxide-containing feedstock (1) to produce a carbon dioxide-rich (gaseous) effluent (3) (i.e. enriched in carbon dioxide compared to the feedstock (1)); a water electrolysis unit (5), suitable for treating water (4) (fresh or recycled) to produce oxygen (6) and hydrogen (7); - a RWGS reaction unit (8) suitable for at least partially converting carbon dioxide from the carbon dioxide-rich effluent (3) into a CO2-rich RWGS gas (9) (i.e. a synthesis gas enriched in CO2 (and water) compared to the carbon dioxide-rich effluent (3)); a Fischer-Tropsch (FT) reaction unit (13) suitable for converting the RWGS gas (9) to produce a Fischer-Tropsch (FT) effluent (14) and, optionally, for generating a first steam (22); the first steam (22) has been generated, for example, by vaporizing water in an exchanger arranged inside the FT reaction unit (13); for supplying thermal energy to the carbon dioxide capture unit (2); - a first separation unit (15), suitable for at least partially treating the FT effluent (14) to give at least the following: a hydrocarbon effluent (17), a first gaseous effluent (33) (off-gas), and a first aqueous effluent (16), which is the product of the Fischer-Tropsch synthesis obtained by condensing gaseous water under the operating conditions of the Fischer-Tropsch reaction; a second separation unit (34) for producing a carbon dioxide-depleted gaseous effluent (18) and a carbon dioxide-rich gaseous effluent (35) from the first gaseous effluent (33), and recycling the carbon dioxide-rich gaseous effluent (35) to the inlet of the RWGS section (8); a partial oxyfuel combustion reaction unit (28) suitable for oxidizing at least a portion (24) of the carbon dioxide-depleted gaseous effluent (18) separated by the second separation unit (34) to produce an oxyfuel combustion effluent (29) containing carbon monoxide and water, and sending the oxyfuel combustion effluent (29) to the FT reaction unit (13); a hydrogen reaction unit (20) (hydrotreating and / or hydrocracking and / or hydroisomerization unit) suitable for treating the hydrocarbon effluent (17) with hydrogen (7) and separating at least one hydrocarbon fraction (21), which may for example comprise at least one of the following fractions: naphtha, gasoline, kerosene, gas oil, and lubricating oil base; - optionally at least one heat exchanger (31) suitable for generating second steam (23) by heat exchange between water and the RWGS gas (9); the second steam (23) can be used, for example, to provide thermal energy to the carbon dioxide capture unit (2); and - preferably a separation unit (10), suitable for treating the RWGS gas (9) to produce a RWGS gas (12), which is depleted in water (compared to the RWGS gas (9)) and sent to the FT reaction unit (13) instead of the RWGS gas (9), and sending the second aqueous effluent (11) to the water electrolysis unit (5).

[0056] Advantageously, the FT reaction unit (13) and optionally the first heat exchanger (31) are suitable for generating water vapor by heat exchange, which advantageously makes it possible to supply energy to the carbon dioxide capture unit (2), for example by regenerating an amine-based solvent (or physical solvent) loaded with carbon dioxide in a regeneration unit of the carbon dioxide capture unit (2), or by feeding it to a temperature swing adsorption device.

[0057] It will be clear to those skilled in the art that in order to avoid unnecessarily complicating the description and drawings, the water supply to the FT reaction unit (13) and the heat exchanger (31) for generating steam have not been described in detail, as have the water outlet from the carbon dioxide capture unit (2).

[0058] (Carbon dioxide capture unit) The carbon dioxide capture unit (2) allows for the separation of carbon dioxide from the remainder of the feedstock (1). Such a carbon dioxide capture unit allows for the provision of CO2 that can be conventionally compressed for upgrading or storage. According to one or more embodiments, the feedstock (1) comprises at least 0.04% by volume of carbon dioxide, preferably at least 2% by volume of carbon dioxide, and highly preferably at least 10% by volume of carbon dioxide.

[0059] According to one or more embodiments, the feedstock (1) comprises or consists of combustion flue gas. According to one or more embodiments, the feedstock (1) comprises a gaseous effluent from at least one unit selected from the group consisting of refineries, incinerators, petrochemical units, chemical units, thermal power plants, paper mills, ethanol plants, and sugar refineries. According to one or more embodiments, the feedstock (1) comprises a gaseous effluent from a cement plant, and / or a gaseous effluent from a lime production unit, and / or a gaseous effluent from a blast furnace. According to one or more embodiments, the combustion smoke originates from a combustion chamber (e.g., a boiler) designed to combust a fuel, such as coal, natural gas, fuel oil, biogas, biomass, organic waste, or municipal waste, with an oxidizing agent, typically air.

[0060] According to one or more embodiments, the feedstock (1) comprises or consists of biogas, natural gas, synthesis gas, refinery gas, biomass fermentation gas, cement plant gas and / or blast furnace gas.

[0061] The carbon dioxide can also be carbon dioxide present in air. According to one or more embodiments, the feedstock (1) comprises or consists of air. For example, the carbon dioxide capture unit (2) can comprise a direct air capture (DAC) device.

[0062] For capture, several agents can be used, such as solvents and solids. According to the present invention, the carbon dioxide capture unit (2) uses at least one amine-based solvent and / or at least one physical solvent, such as one based on polyethylene glycol dimethyl ether, and / or a temperature swing adsorption (physical adsorption) facility.

[0063] One widespread carbon dioxide capture technology is based on the phenomenon of absorption, i.e., the transfer of chemical species from a gas to a liquid. The gas containing the impurities, or species to be separated, is sent to a column where it is contacted with a liquid solvent; the two streams can be used in various hydrodynamic configurations (co-current, cross-current, or counter-current, with counter-current solutions being preferred for reasons of favorable thermodynamic equilibrium). The absorption is carried out using an absorption solution containing a chemical or physical solvent; this distinction relates to whether there is a chemical reaction between the absorbed component and the solvent.

[0064] Physical absorption is preferred from the standpoint of minimizing the energy costs of the process; this is particularly suitable in cases where the partial pressure of the species to be separated is high.

[0065] Chemical absorption is preferred when the dilution and partial pressure of the species to be separated is high and / or when a high recovery of this species is desired, or finally when it is desired to achieve strict specifications regarding the maximum allowable concentration of this species in the gas stream once scrubbed. Therefore, for the capture of carbon dioxide from (industrial) flue gases with low carbon dioxide concentration values, typically 3% to 15% by volume (typically in low pressure gas), scrubbing by chemical absorption, for example with amine solvents, for example of the alkanolamine type, is well suited.

[0066] The absorbent solutions commonly used today are aqueous solutions containing one or more reactive compounds or compounds with physicochemical affinity for acidic compounds. The reactive compounds can be, for example, but not limited to, amines (primary, secondary, tertiary, cyclic or acyclic, aromatic or non-aromatic, saturated or unsaturated), alkanolamines, polyamines, amino acids, alkali metal salts of amino acids, amides, urea, alkali metal phosphates, carbonates, or borates. According to one or more embodiments, the absorbent solution is an aqueous solution containing one or more reactive compounds with amine functional groups, the structure of which is described in patent application WO2007 / 104856, page 6, line 1 to page 7, line 3.

[0067] According to one or more embodiments, the reactive compound comprises 10% to 90% by weight of the total weight of the absorbent solution, preferably 20% to 50% by weight, and highly preferably 25% to 40% by weight.

[0068] Chemical absorption in amine solvents is based on acid-base equilibrium: low temperatures favor the reaction between basic amines and acidic carbon dioxide, while high temperatures favor the reverse reaction. Therefore, an amine process, for example, using an aqueous phase containing 20-50% by weight of one or more amines, can employ two columns (not shown) through which the solvent flows from one to the other. In the first column, called the absorber, the stream to be scrubbed (i.e., feedstock (1)) is contacted with the amine solvent at low temperature. The amine solvent enters the column and captures carbon dioxide. At the bottom of the column, the amine solvent (the "rich" solvent) reaches a predetermined loading rate, which is the ratio of the moles of captured carbon dioxide to the moles of amine. At the top of the column, the gas stream exits with a carbon dioxide content that meets the specified specifications, e.g., nearly 10 times lower than the initial content in the flue gas. The rich solvent is sent to the second column, called the regenerator, whose operation is similar to that of a distillation column operating at high temperatures. The regenerated amine solvent ("lean" solvent) can itself be sent back to the absorber. The amine solvent is therefore continuously circulated in a closed loop from one column to the other, preferably through a feed / effluent heat exchanger, to cool the lean solvent and preheat the rich solvent while conserving energy throughout the process.

[0069] According to one or more embodiments, the regenerator operates at an elevated temperature at the bottom of the column, between 90°C and 250°C, preferably between 110°C and 240°C, and highly preferably between 120°C and 200°C.

[0070] The carbon dioxide released from the regenerator can then optionally be compressed and upgraded. According to one or more embodiments, the carbon dioxide-rich effluent (3) comprises at least 90% by volume carbon dioxide, preferably at least 95% by volume carbon dioxide, and highly preferably at least 98% by volume carbon dioxide. According to one or more embodiments, the temperature of the carbon dioxide-rich effluent (3) upon leaving the carbon dioxide capture unit (2) is between 20°C and 250°C, preferably between 30°C and 200°C, and highly preferably between 40°C and 150°C. According to one or more embodiments, the pressure of the carbon dioxide-rich effluent (3) upon leaving the carbon dioxide capture unit (2) is between 0.20 MPa and 4 MPa, preferably between 0.30 MPa and 3.5 MPa, and highly preferably between 0.4 MPa and 3 MPa.

[0071] An essential aspect of the operation for the solvent treatment of industrial flue gases is the step of regenerating the separating agent. Depending on the type of absorption (physical and / or chemical), regeneration by expansion and / or by distillation and / or by entrainment with a vaporized gas known as "stripping gas" is generally envisaged.

[0072] One of the main limitations of solvents commonly used today is the need to use high flow rates of absorbent solution, which leads to high energy consumption for solvent regeneration and large equipment sizes (columns, pumps, etc.). This is especially true when the partial pressure of carbon dioxide is low. Such energy consumption represents a significant operating cost for carbon dioxide capture processes. The regeneration energy depends on the nature of the amine and the partial pressure of carbon dioxide and is typically 2 GJ / t (carbon dioxide) to 4 GJ / t (carbon dioxide) per ton of captured carbon dioxide. New capture methods tend to reduce this energy, tending toward values ​​below 2 GJ / t (carbon dioxide) per ton of carbon dioxide. In the context of air treatment, where the concentration of carbon dioxide is very low, the energy consumed is very high, on the order of 5 GJ / t (carbon dioxide) to 7.5 GJ / t (carbon dioxide) per ton of carbon dioxide.

[0073] Another possible embodiment is based on the principle of adsorption by a solid adsorbent with a strong chemical affinity for carbon dioxide. To ensure a continuous operating mode, the method operates with several reactors in parallel. Carbon dioxide is adsorbed on the solid adsorbent, and the stream to be treated (i.e., feedstock (1)) is depleted as it passes through the bed of solids, and at the outlet, the stream no longer contains, or contains very little, carbon dioxide. However, the solid adsorbent gradually becomes saturated and can no longer adsorb carbon dioxide. The stream to be treated is then sent to another reactor containing a solid adsorbent that is not saturated with carbon dioxide, and the capture operation continues. At the same time, the reactor saturated with carbon dioxide undergoes the following regeneration operation: - An increase in temperature refers to temperature swing adsorption (TSA); and - Partial vacuum refers to pressure swing adsorption (or VPSA (vacuum pressure swing adsorption), or simply VSA or PSA, sometimes simply VSA or PSA in the presence of a gas that promotes desorption).

[0074] A barrier to the TSA process is the large amount of heat required for regeneration. The heat integration proposed in this invention makes it possible to remove this barrier.

[0075] According to one or more embodiments, the solid adsorbent for carbon dioxide capture is selected from the following compounds: activated carbon, zeolite, alumina, silica, synthetic fibers with or without impregnated amines, metal-organic framework (MOF) solids, and supported alkali metal carbonates. These solid adsorbents are increasingly being used to capture carbon dioxide from air. In these cases, the energy required for regeneration of the adsorbent by physical adsorption, for example on zeolites, is on the order of 0.6-0.9 GJ / t of carbon dioxide by weight (t). In the case of solid-supported amines, the regeneration energy is 5.4-7.2 GJ / t of carbon dioxide by weight (t).

[0076] Advantageously, the energy required to regenerate the amine solvent and / or increase the temperature of the solid sorbent can be at least partially supplied by the first steam (22), and optionally by the second steam (23). This energy input to the carbon dioxide capture unit (2) allows for maximizing the energy efficiency of the process.

[0077] According to one or more embodiments, the temperature of the steam (22) and / or (23), for example at the outlet of the heat exchanger (31) and / or the FT reaction unit (13), is at least 110°C, preferably at least 120°C, and highly preferably at least 130°C. According to one or more embodiments, the temperature of the steam (22) and / or (23), for example at the outlet of the heat exchanger (31) and / or the FT reaction unit (13), is between 110°C and 270°C, preferably between 120°C and 260°C, and highly preferably between 130°C and 220°C. According to one or more embodiments, the pressure of the steam (22) and / or (23), for example at the outlet of the heat exchanger (31) and / or the FT reaction unit (13), is between 0.1 MPa and 4 MPa, preferably between 0.1 MPa and 3.5 MPa, and highly preferably between 0.1 MPa and 1.7 MPa.

[0078] (Water electrolysis unit) The water electrolysis unit (5) processes water (4) from: a supply line and / or an optional third separation unit (10) and / or a first separation unit (15).

[0079] According to one or more embodiments, the water electrolysis unit (5) comprises a pre-treatment section suitable for extracting oxygen-containing compounds from the water (4), for example from the first aqueous effluent (16).

[0080] According to one or more embodiments, the water electrolysis unit (5) comprises at least one alkaline electrolyzer. Other electrolyzer technologies can be used for the water electrolysis unit, such as proton exchange membrane (PEM) electrolysis, solid oxide electrolysis (SOE), or anion exchange membrane (AEM) electrolysis. The operating conditions (temperature, pressure, nature of the electrolyte, electrodes, and diaphragms / membranes) are specific to each technology.

[0081] According to one or more embodiments, the water electrolysis unit (5) comprises at least one reactor operated under at least one of the following operating conditions: Alkaline electrolysis equipment: - The temperature is 60℃~90℃. the pressure is between 0.1 MPa and 20 MPa, preferably between 0.1 MPa and 4 MPa; - the electrolyte comprises KOH; the electrode comprises a metal alloy; - the diaphragm contains asbestos, polytetrafluoroethylene and / or nickel oxide; Proton Exchange Membrane (PEM) Electrolyzer: - The temperature is 50℃~80℃, the pressure is between 0.1 MPa and 20 MPa, preferably between 1.8 MPa and 5.5 MPa; the electrolyte comprises a polymer membrane; - the electrode comprises a metal alloy; Solid oxide electrolyzer (SOE): - The temperature is 800℃-900℃. the pressure is between 0.1 MPa and 2 MPa, preferably between 0.1 MPa and 0.5 MPa; the electrolyte comprises a ceramic (e.g. perovskite) membrane; - the electrode comprises a metal alloy; Anion Exchange Membrane (AEM) Electrolyzer: - The temperature is 50℃~70℃. the pressure is between 0.1 MPa and 20 MPa, preferably between 0.1 MPa and 3.5 MPa; the electrolyte comprises a polymer membrane; The electrode comprises a metal alloy.

[0082] According to one or more embodiments, the oxygen (6) produced by the water electrolysis unit (5) contains 99.0% to 99.8% by weight of O2 (after drying).

[0083] According to one or more embodiments, the hydrogen (7) produced by the water electrolysis unit (5) contains 99.5% to 99.999% H2 (after drying) by weight.

[0084] Advantageously, oxygen (6) is used for partial oxy-fuel combustion. The oxygen (6) produced by the water electrolysis unit (5) can be used for this purpose. According to one or more embodiments, the oxygen (6) can be purified if necessary and compressed if the oxy-fuel combustion is carried out at a pressure higher than the pressure at which the oxygen (6) is produced in the water electrolysis unit (5).

[0085] Therefore, the present invention makes it possible to generate heat by upgrading the oxygen (6) produced by the water electrolysis unit (5) in an oxyfuel combustion unit, and to introduce the resulting oxyfuel combustion effluent (29) directly into the FT reaction unit (13). Therefore, part of the energy used in the electrolysis can be reintroduced into the system in the form of heat via oxygen (6) as the energy carrier. This represents an advantage over conventional oxyfuel combustion operations, which require high-purity oxygen to be produced from the separation of oxygen from air, a process that is costly in terms of energy.

[0086] According to one or more embodiments, the water electrolysis unit (5) is based on solid oxide electrolyzer (SOE) technology, and at least a portion of the water (4) can be in the form of steam, at least partially provided by the first steam source (22) and optionally the second steam source (23). This energy input to the electrolysis unit (5) makes it possible to improve the energy efficiency of the process.

[0087] (RWGS reaction unit) The RWGS reaction unit (8) produces RWGS gas (9) (synthesis gas), which is enriched in CO (and hydrogen-depleted) compared to the carbon dioxide-rich effluents (3) and (35), which contain unconverted carbon dioxide and water. The hydrogen (7) required for the RWGS reaction comes from the water electrolysis unit (5).

[0088] According to one or more embodiments, the RWGS reaction section (8) comprises at least one reactor operated under at least one of the following operating conditions: the temperature is between 700°C and 1200°C, preferentially between 800°C and 1100°C, and even more preferentially between 850°C and 1050°C; - the pressure is between 0.1 MPa and 10 MPa, preferentially between 0.1 MPa and 5 MPa, more preferentially between 0.1 MPa and 3.5 MPa; - The gas space velocity is 5000NL / kg at the reactor inlet. cata / h~40,000NL / kg cata / h; The catalyst is based on the elements Ni, Cu, Fe, Co or noble 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 or siliceous alumina.

[0089] According to one or more embodiments, the amount of hydrogen at the inlet of the RWGS reaction unit (8) is adjusted so that the H2 / CO molar ratio at the outlet of the RWGS reaction unit (8) meets the requirements of the FT unit, i.e., 0.5-4, preferably 1-3, more preferably 1.5-2.5.

[0090] According to one or more embodiments, the temperature of the RWGS gas (9) at the outlet of the RWGS reaction unit (8) is at least 700°C, preferably at least 750°C, and highly preferably at least 800°C.

[0091] In one or more embodiments, at least a portion of the RWGS gas (9) supplies energy to the regeneration unit of the carbon dioxide capture unit (2) at the outlet of the RWGS reaction unit (8), preferably directly, by a first heat exchanger (31) that generates second water vapor (23) by (indirect) heat exchange between water (not shown) and the RWGS gas (9).

[0092] The RWGS gas (9) is preferably sent to a third separation unit (10).

[0093] (Fischer-Tropsch Reaction Unit) According to the present invention, in the FT reaction unit (13), the carbon monoxide and hydrogen present in the (preferably water-depleted) RWGS gas (9) are reacted to produce a stream comprising the FT effluent (14), which comprises unconverted synthesis gas, carbon dioxide, gaseous and liquid hydrocarbon products and water.

[0094] According to one or more embodiments, the (preferably water-depleted) RWGS gas (9) sent to the FT reaction unit (13) comprises carbon monoxide and hydrogen in a H2 / CO molar ratio of 0.5 to 4, preferably 1 to 3, more preferably 1.5 to 2.5. According to one or more embodiments, the amount of hydrogen upstream (e.g., at the inlet) of the FT reaction unit (13) is adjusted, e.g., by an optional hydrogen feed, such that the H2 / CO molar ratio is as defined above.

[0095] The FT reaction unit (13) is used in a reaction unit containing one or more suitable reactors, the technology of which is known to those skilled in the art, which may be, for example, one or more multi-tubular fixed bed reactors, or one or more slurry bubble column reactors, or one or more microchannel reactors.

[0096] According to one or more embodiments, the FT reaction unit (13) uses one or more bubble column reactors. Since the synthesis is highly exothermic, this embodiment allows, among other things, improved thermal control of the reactors and only small pressure drops.

[0097] The catalyst used in this Fischer-Tropsch synthesis is generally any catalytic solid known to those skilled in the art for carrying out Fischer-Tropsch synthesis. According to one or more embodiments, the catalyst used in the Fischer-Tropsch synthesis comprises cobalt or iron, preferably cobalt. The catalyst used is generally a supported catalyst. The support may be based on, for example, alumina, silica, silica-alumina, siliceous alumina, or titanium.

[0098] According to one or more embodiments, the FT reaction unit (13) comprises at least one reactor operated under at least one of the following operating conditions: the temperature is between 170°C and 280°C, preferentially between 190°C and 260°C, preferentially between 210°C and 240°C; the absolute pressure is between 1.0 MPa and 6.0 MPa, preferably between 1.5 MPa and 3.5 MPa, and preferentially between 2.0 MPa and 3.0 MPa.

[0099] The FT effluent (14) is sent to the first separation unit (15). According to one or more embodiments, the temperature of the FT effluent (14) at the outlet of the FT reaction unit (13) is at least 170°C, preferably at least 190°C, and highly preferably at least 210°C.

[0100] According to one or more embodiments, the FT reaction unit (13) is adapted to generate a first steam (22) and supply heat energy to the carbon dioxide capture unit (2). The first steam (22) is generated, for example, by vaporizing water (not shown) in a heat exchanger arranged inside the FT reaction unit (13), allowing for the rejection of heat energy from the Fischer-Tropsch reaction (which is an exothermic reaction).

[0101] (First Separation Unit) In the first separation unit (15), at least a portion (first portion) of the FT effluent (14) is treated to produce: - hydrocarbon effluent (17) (less water compared to FT effluent (14)), a first gaseous effluent (33), and - a first aqueous effluent (16).

[0102] According to one or more embodiments, a second portion of the FT effluent (14) is sent directly to the hydrogen reaction unit (20). Preferably, said second portion of the FT effluent (14) is a liquid fraction, preferably containing little or no water, and preferably containing little or no water.

[0103] At the outlet of the first separation unit (15), the hydrocarbon effluent (17) is sent to the hydrogen reaction unit (20) and the first aqueous effluent (16) is optionally sent to the water electrolysis unit (5) by a first recycle line.

[0104] According to one or more embodiments, the hydrocarbon effluent (17) comprises the following resulting from the condensation of gaseous hydrocarbons under the operating conditions of the Fischer-Tropsch reaction: n-paraffins, olefins, and oxygenated compounds.

[0105] According to one or more embodiments, the hydrocarbon effluent (17) contains less than 5% by weight of water, preferably less than 2% by weight of water, and highly preferably less than 1% by weight of water.

[0106] According to one or more embodiments, the first aqueous effluent (16) is generated from a Fischer-Tropsch synthesis resulting from condensation of gaseous water under the operating conditions of the Fischer-Tropsch reaction.

[0107] According to one or more embodiments, the first gaseous effluent (33) comprises unconverted synthesis gas, carbon dioxide, and gaseous hydrocarbons, such as (predominantly) C1-C4 paraffins, C2-C4 olefins, and C1-C3 oxygenated compounds.

[0108] (Second Separation Unit) In the second separation unit (34), the first effluent (33) from the first separation unit (15) is treated to produce: - Carbon dioxide depleted gaseous effluent (18); and a gaseous effluent (35) enriched in carbon dioxide compared to the carbon dioxide content of the first gaseous effluent (33).

[0109] According to a first embodiment, the second separation unit (34) is a membrane separation unit. Membrane separation methods were initially not widely recommended for post-combustion carbon dioxide capture, with gas-liquid absorption in chemical solvents considered the most mature and suitable technology for this operation. However, modern technologies make it possible to economically separate carbon dioxide using membranes (high-density polymers, inorganic materials, hybrid matrices, liquid membranes). Reference may be made to the review article: Oil Gas Sci. Technol. - Rev. IFP Energies nouvelles, Volume 69, Number 6, November-December 2014. The main performance features are the capture rate and a carbon dioxide purity of more than 90%.

[0110] According to a second embodiment, the second separation unit (34) is a carbon dioxide capture unit based on the absorption of carbon dioxide in a solvent.

[0111] According to a third embodiment, the second separation unit (34) is a carbon dioxide capture unit based on the absorption of carbon dioxide on a solid.

[0112] According to one or more embodiments, a (first) portion (19) of the carbon dioxide-depleted gaseous effluent (18) is sent to the FT reaction unit (13) by a second recycle line.

[0113] According to one or more embodiments, at least a portion (second portion) (24) of the carbon dioxide-depleted gaseous effluent (18) is processed by a first turbine (26) to generate electricity, and gas (27) exiting the first turbine (26) is sent to a partial oxyfuel combustion reaction unit (28).

[0114] According to one or more embodiments, a (third) portion (not shown) of the carbon dioxide-depleted gaseous effluent (18) is recycled to the RWGS reaction unit (8) and converted to synthesis gas, thereby improving the mass yield of the process line.

[0115] According to one or more embodiments, a (fourth) portion (not shown) of the carbon dioxide-depleted gaseous effluent (18) is sent to a separate synthesis gas production unit, for example of the following type: - Partial oxidation (or POx); - Steam methane reforming (or SMR); - Autothermal reforming (or ATR); - Enhanced Heat Transfer Reforming (or EHTR).

[0116] According to one or more embodiments, the synthesis gas produced in a separate unit is recycled to the inlet or outlet of the RWGS reaction unit (8).

[0117] (Partial Oxyfuel Combustion Reaction Unit) According to the present invention, at least a portion (24) of the gaseous effluent (18) is sent to a partial oxyfuel combustion reaction unit (28) where the hydrocarbon compounds present, carbon monoxide and hydrogen (i.e., CO, H, paraffins and olefins having 1 to 7 carbon atoms per molecule, and alcohol compounds having 1 to 3 carbon atoms per molecule) are at least partially converted to carbon dioxide and water in the presence of oxygen (6), resulting in oxyfuel combustion gases comprising (essentially) carbon dioxide and water (and optionally CO and H, if partial oxyfuel combustion).

[0118] Complete oxyfuel combustion is a common method in the glass, cement, and steel industries. The main difference from conventional combustion in the presence of air is that the fuel is burned in the presence of high-purity oxygen. High-purity oxygen (O2) (i.e., purity of at least 95% by weight, preferably at least 98% by weight, and highly preferably at least 99% by weight) can be produced by an air separation unit that removes atmospheric nitrogen (N2) from the oxidant stream or by water electrolysis. An exhaust gas called oxyfuel combustion effluent (29), which contains a high concentration of carbon dioxide and water vapor (compared to the gaseous effluent (18)), is then produced at the oxyfuel combustion outlet. Oxyfuel combustion technology is well known to those skilled in the art; reference may be made, for example, to the following: Int. J. Energy Res., 2017, 41, pp. 1670-1708; Energies 2021, 14, p. 4333; and WO 2006 / 013290.

[0119] Partial oxyfuel combustion (POX), sometimes referred to as gasification technology, is a slightly exothermic process that can be used as an alternative to methane steam reforming to produce synthesis gas or hydrogen. This reaction can be applied not only to hydrocarbons (light, heavy, asphalt, petroleum coke) but also to coal and biomass (e.g., wood, food waste, etc.). Partial oxyfuel combustion is preferably carried out at high temperatures (e.g., 1100°C to 1500°C) and pressures (e.g., 1 MPa to 9 MPa or higher) in the presence of high-purity oxygen without a catalyst. The reaction corresponds to partial oxidation itself. It involves preheating the gas mixture, e.g., to temperatures ranging from 1000°C to 1400°C, for example, by preheating to 300°C. Industrial partial oxyfuel combustion processes are well known to those skilled in the art and are commercially available from companies such as Shell, Texaco, BASF-Lurgi, and Air Liquide. See, for example, Ullmann's Encyclopedia of Industrial Chemistry, Chapter 2: Hydrogen Production (p. 249, vol. 18) and the Encyclopedia of Carbon Monoxide (p. 679, vol. 6).

[0120] In the case of partial oxyfuel combustion operation, it will preferably be carried out with an oxygen stoichiometry such as to obtain oxidation of a mixture of hydrocarbons, hydrogen and carbon monoxide and with a maximum concentration of carbon monoxide in the oxyfuel combustion effluent (29).

[0121] To control the adiabatic flame temperature, which can rise from 1900°C with air to 2800°C with 95% O2, an inert gas can be used, such as water vapor or carbon dioxide.

[0122] According to one or more embodiments, a portion of the carbon dioxide-rich effluent (3) is introduced into a partial oxy-fuel combustion unit (28) to achieve a desired oxy-fuel combustion temperature range. This introduction can occur directly into the partial oxy-fuel combustion unit (28), after premixing with at least a second portion (24) of the gaseous effluent (18), or after mixing with oxygen (6). According to one or more embodiments, the oxygen flow rate is adjusted to achieve a target temperature in the oxy-fuel combustion chamber and minimize the content of light hydrocarbons in the oxy-fuel combustion effluent (29).

[0123] According to one or more embodiments, the partial oxyfuel combustion reaction unit (28) comprises at least one reactor and is operated under at least one of the following operating conditions: the absolute pressure is between 0.1 MPa and 9 MPa, preferably between 1 MPa and 4 MPa; the temperature is between 600°C and 2000°C, preferentially between 800°C and 1700°C; preferentially between 1100°C and 1500°C; and - Oxygen is present for combustion; the oxygenation ratio is 0.3-0.8, preferably 0.4-0.7, to promote the formation of carbon monoxide. The oxygenation ratio is defined as the ratio of the molar flow rate of injected oxygen to the theoretical oxygen flow rate for complete oxidation of all hydrocarbons.

[0124] According to one or more embodiments, the "light" hydrocarbon fraction (not shown) obtained from the hydrogen reaction unit (20) is sent, at least in part, to a partial oxyfuel combustion reaction unit (28) (not shown). According to one or more embodiments, the hydrocarbon fraction comprises gaseous hydrocarbons, such as (predominantly) C1-C4 paraffins, C2-C4 olefins, and C1-C3 oxygen-containing compounds.

[0125] According to one or more embodiments, the temperature of the oxy-fuel combustion gas produced in the partial oxy-fuel combustion reaction unit (28) is between 600°C and 2000°C, preferably between 800°C and 1700°C, preferably between 900°C and 1500°C, and the absolute pressure is between 0.1 MPa and 9 MPa, preferably between 1 MPa and 4 MPa.

[0126] The high temperature of the oxyfuel combustion gas produced in the partial oxyfuel combustion reaction unit (28) allows it to supply some of the required thermal energy to the RWGS reaction unit (8) and / or the carbon dioxide capture unit (2) via a feed line (32).

[0127] The input of thermal energy may be by heat exchange with water vapor produced by the partial oxy-fuel combustion reaction unit (28) and / or within the oxy-fuel combustion chamber of the partial oxy-fuel combustion reaction unit (28), for example.

[0128] Advantageously, the partial oxyfuel combustion reaction unit (28) makes it possible to convert substantially all of the hydrocarbon by-products of the process into CO and thus upgrade them to the form of desired products, thus improving the yield of the desired products of the process according to the invention.

[0129] The oxyfuel combustion effluent (29) at the outlet of the partial oxyfuel combustion reaction unit (28) is recycled to the inlet of the FT reaction unit (13).

[0130] (Hydrogen reaction unit) The hydrocarbon effluent (17) is sent to a hydrogen reaction unit (20) to undergo hydrotreating and / or hydrocracking and / or hydroisomerization reactions, allowing one or more hydrocarbon fractions (21) to be upgraded, in particular to very high quality (essentially free of sulfur, aromatics, and nitrogen) synthetic fuels, i.e., gasoline, kerosene, gas oil, and / or other hydrocarbon products, such as naphtha, or lubricating oil bases. One possible option is the production of paraffinic fractions, C10-C13 fractions intended for the production of base products for petrochemical processes, for example, linear alkylbenzenes (LAB), or alternatively waxes for various industrial uses.

[0131] According to one or more embodiments, the hydrogen reaction unit (20) comprises at least one reactor and is operated under at least one of the following operating conditions: the temperature is between 250°C and 450°C, more preferentially between 280°C and 450°C, even more preferentially between 320°C and 420°C; the pressure is between 0.2 MPa and 15 MPa, preferably between 0.5 MPa and 12 MPa, more preferably between 1 MPa and 10 MPa; - Space velocity is defined as the ratio of the volumetric flow rate of the feedstock to the volume of the catalyst at ambient temperature and pressure, 0.1h -1 ~10h -1 , preferably 0.2 h -1 ~7h -1 , and more preferentially 0.5h -1 ~5h -1 is; the hydrogen flow rate is between 100 and 2000 normal liters of hydrogen per liter of volume of feedstock and per hour, preferably between 150 and 1500 normal liters of hydrogen per liter of volume of feedstock and more preferentially between 300 and 1500 normal liters of hydrogen per liter of volume of feedstock.

[0132] According to one or more embodiments, the hydrotreating and / or hydrocracking and / or hydroisomerization catalyst comprises at least one hydrodehydrogenating metal selected from the group comprising metals from groups VIB and VIIIB of the periodic table, at least one solid that is a Brønsted acid, i.e., a solid capable of releasing one or more protons, and optionally a binder.

[0133] According to one or more embodiments, the hydrotreating and / or hydrocracking and / or hydroisomerization catalyst comprises at least one Group VIIIB noble metal selected from ruthenium, rhodium, palladium, osmium, iridium and platinum, preferably platinum and palladium, employed alone or in mixtures, preferably in their reduced form.

[0134] According to one or more embodiments, the hydrotreating and / or hydrocracking and / or hydroisomerization catalyst comprises: at least one metal selected from nickel, molybdenum, tungsten, cobalt, ruthenium, indium, palladium, and platinum; and at least one support selected from alumina, boron oxide, magnesia, zirconia, titanium oxide, and clay. According to one or more embodiments, the support is alumina, silica-alumina, siliceous alumina, or silica.

[0135] According to one or more embodiments, the hydrotreating and / or hydrocracking and / or hydroisomerization catalyst comprises at least one Group VIIIB base metal selected from nickel and cobalt in combination with at least one Group VIB metal selected from molybdenum and tungsten, used alone or as a mixture, preferably in the form of their sulfides.

[0136] According to one or more embodiments, in the case where the hydrotreating and / or hydrocracking and / or hydroisomerization catalyst comprises at least one Group VIIIB noble metal, the content of noble metal in the catalyst is between 0.01% and 5% by weight, preferably between 0.05% and 4% by weight, and very preferentially between 0.10% and 2% by weight, relative to the total weight of the catalyst.

[0137] According to one or more embodiments, in the case where the hydrotreating and / or hydrocracking and / or hydroisomerization catalyst comprises at least one Group VIB metal in combination with at least one non-noble Group VIII metal selected from nickel and cobalt, the content of Group VIB metal in the catalyst, expressed as oxide equivalent, is between 5% and 40% by weight, preferably between 10% and 35% by weight, relative to the total weight of the catalyst, and the content of Group VIIIB metal in the catalyst, expressed as oxide equivalent, is between 0.5% and 15% by weight, preferably between 1% and 10% by weight, preferably between 1% and 8% by weight, and very preferentially between 1.5% and 6% by weight.

[0138] According to one or more embodiments, the hydrotreating and / or hydrocracking and / or hydroisomerization catalyst comprises or consists of at least one noble metal and a support comprising or consisting of at least one zeolite and at least one binder.

[0139] According to one or more embodiments, the zeolite-based hydrotreating and / or hydrocracking and / or hydroisomerization catalyst is advantageously of the bifunctional type, i.e. it has a hydrodehydrogenation function and a hydroisomerization function.

[0140] (Third Separation Unit) In the third separation unit (10), the RWGS gas (9) is treated, for example by condensation, to produce a water-depleted (compared to the RWGS gas (9)) RWGS gas (12), for example by recycling the second aqueous effluent (11) to the water electrolysis unit (5).

[0141] According to one or more embodiments, the water-reduced RWGS gas (12) contains less than 1 mole % water, preferably less than 0.5 mole % water, and highly preferably less than 0.25 mole % water.

[0142] The water-reduced RWGS gas (12) is sent to the FT reaction unit (13).

[0143] (Turbine) Referring to Figure 1, according to one or more embodiments, the present invention allows for the recovery of energy in the form of electricity by at least one turbine (26).

[0144] According to one or more embodiments, the first turbine (26) is adapted to process at least a portion (24) of the carbon dioxide-depleted gaseous effluent (18) to generate electricity.

[0145] According to one or more embodiments, a second turbine (not shown) is adapted to process, at least in part, the first steam (22) and / or the second steam (23) to generate electricity (not shown).

[0146] According to one or more embodiments, electricity is used to provide thermal energy to the RWGS reaction unit (8) and / or the carbon dioxide capture unit (2) and / or the water electrolysis unit (5). According to one or more embodiments, electricity (25) is used to provide thermal energy to the RWGS reaction unit (8). According to one or more embodiments, electricity (25) can be used to power an electric furnace for preheating the feedstock for the RWGS reaction unit (8).

[0147] (Carbon dioxide separation unit) According to one or more embodiments, the device further comprises a unit for separating carbon dioxide and optionally methane (not shown), compounds potentially present in the RWGS gas (9). Advantageously, the carbon dioxide can be recycled to the RWGS reaction unit (8).

[0148] According to one or more embodiments, the carbon dioxide separation unit is located between the RWGS reaction unit (8) and the FT reaction unit (13). Advantageously, the size of the FT reaction unit (13) can therefore be reduced.

[0149] According to one or more embodiments, the carbon dioxide separation unit is located at the outlet of the FT reaction unit (13).

[0150] (additional oxyfuel combustion unit) According to one or more embodiments, the oxygen (6) obtained from the water electrolysis unit is upgraded (partial or complete oxidation) in an additional oxyfuel combustion unit to convert the formed methane present in the RWGS gases (9) separated by, for example, a carbon dioxide separation unit.

[0151] (Effluent purification unit) According to one or more embodiments, the carbon dioxide-rich effluent (3) and / or the carbon dioxide-rich gaseous effluent (35) are introduced into the RWGS reaction unit (8) after purification, either separately or after mixing. According to one or more embodiments, the RWGS gas (9) is introduced into the FT reaction unit (13) upstream or downstream of the third separation unit (10) after purification. According to one or more embodiments, the first aqueous effluent (16) is introduced into the water electrolysis unit (5) after purification. The effluent purification process aims to at least partially remove sulfur- and nitrogen-containing compounds, halogens, heavy metals, and transition metals. The main techniques for purifying gases are as follows: adsorption, absorption, and catalytic reaction.

[0152] In this patent application, the groups of chemical elements are conventionally given according to the CAS classification (CRC Handbook of Chemistry and Physics, published by CRC Press, editor-in-chief DR Lide, 81st edition, 2000-2001). For example, group VIIIB according to the CAS classification corresponds to metals from columns 8, 9 and 10 according to the new IUPAC classification; group VIB according to the CAS classification corresponds to metals from column 6 according to the new IUPAC classification.

[0153] (Example) The various examples relate to arrangements which may or may not be in accordance with the present invention, the object of which is to produce a hydrocarbon fraction from a flue gas containing 21% by weight of carbon dioxide. The flow rate of the flue gas to be treated is 3641 kg / h for all examples.

[0154] (Example 1: Not in accordance with the present invention) Example 1 illustrates an operating sequence for generating heat for the RWGS reaction unit (8) with upgrading of a portion (24) of the carbon dioxide-depleted gaseous effluent (18) to a unit for combustion in air. The carbon dioxide-depleted gaseous effluent (18) is obtained from a second separation unit (34) and allows for the removal of a portion of the carbon dioxide from the effluent (33) obtained from the first separation unit (15). The carbon dioxide-rich gaseous effluent (35) is sent to the RWGS reaction unit (8). A portion (24) of the carbon dioxide-depleted gaseous effluent (18) is sent to a combustion unit. The combustion effluent from the combustion unit is sent to a carbon dioxide capture unit (2).

[0155] The flue gas flow rate fed to the carbon dioxide capture unit (2) is 3641 kg / h, to which must be added the flue gas flow rate of the combustion effluent from the combustion unit, resulting in a total flow rate of 5332 kg / h of feedstock (1). The carbon dioxide-rich effluent (3) stream from the carbon dioxide capture unit (2) is mixed with the carbon dioxide-rich gaseous effluent (35) for a total flow rate of 1352 kg / h, which is sent to the RWGS reaction unit (8).

[0156] 1403 kg / h of water (4) is supplied to the water electrolysis unit (5), of which 709 kg / h is fresh water. The power consumption of the water electrolysis unit (5) is 6.6 MWe.

[0157] The amount of first steam (22) generated by the FT reaction unit (13) is 1377 kg / h. The heat exchanger (31) generates 1332 kg / h of second steam (23) from the 2392 kg / h required for the operation of the carbon dioxide capture unit (2) and the second separation unit (34). The steam requirements of the reboilers of the carbon dioxide capture unit (2) and the second separation unit (34) are covered.

[0158] The production of hydrocarbon fraction (21) is 186 kg / h.

[0159] Table 1 summarizes the flow rates at the inlet and outlet of the unit of the present process.

[0160] [Table 1]

[0161] Requirements: - Water electrolysis unit (5) consumption: 6.6 MWe; - Heat consumed by the RWGS reaction unit (8) at 864 °C: 0.2 MWth; - Heat required to preheat the RWGS unit feedstock ((3) + (35) + (7)) to 864°C: 0.8 MWth; - Steam to the reboiler of the carbon dioxide capture unit (2): 2002 kg / h; - Steam to the reboiler of the second separation unit (34): 390 kg / h.

[0162] Energy Recovery: - heat released by the reaction unit for combustion in air (with 20% excess air) at 1200 ° C: 0.56 MWth; - Heat recovered during cooling of the flue gases at the outlet of the reaction unit for combustion in air from 1200 ° C to 150 ° C: 0.7 MWth (partial preheating of the feedstock (3) + (35) + (7)) at the inlet of unit (8); - steam generated in the heat exchanger (31): 1332 kg / h; - steam generated in the FT reaction unit (13): 1377 kg / h; - Power generation from the first turbine (26): 3.5 kWe.

[0163] (Example 2: Consistent with the present invention) Example 2 illustrates an operating sequence for generating heat for the RWGS reaction unit (8) with upgrading of a portion (24) of the carbon dioxide-depleted gaseous effluent (18) to a reaction unit (28) for partial oxidation in oxygen. The carbon dioxide-depleted gaseous effluent (18) is obtained from a second separation unit (34), which allows for partial removal of carbon dioxide from the effluent (33) obtained from the first separation unit (15). The carbon dioxide-rich gaseous effluent (35) is sent to the RWGS reaction unit (8). A portion (24) of the carbon dioxide-depleted gaseous effluent (18) is sent to a reaction unit (28) for partial oxidation in oxygen. The partial oxyfuel combustion effluent (29) from the reaction unit (28) for partial oxidation in oxygen is sent to the Fischer-Tropsch reaction unit (13).

[0164] The total flow rate of the flue gases feeding the carbon dioxide capture unit (2) is 3641 kg / h. The addition of the carbon dioxide-rich gaseous effluent (35) (from the second separation unit (34)) to the carbon dioxide-rich effluent (3) makes it possible to achieve a CO flow rate of 987 kg / h at the inlet of the RWGS reaction unit (8).

[0165] The partial oxyfuel combustion effluent (29) is mixed with the RWGS gas (9) from the RWGS reaction unit (8) before the heat exchanger (31).

[0166] 1230 kg / h of water (4) is fed to the water electrolysis unit (5), of which 504 kg / h is fresh water. The power consumption of the water electrolysis unit (5) is 5.4 MWe.

[0167] The amount of primary steam (22) generated by the FT reaction unit (13) is 1880 kg / h. The heat exchanger (31) generates 1660 kg / h of secondary steam (23) out of the 1355 kg / h required for the operation of units (2) and (32). This covers the steam requirements of the carbon dioxide capture unit (2) and the reboiler of unit (32).

[0168] The flow rate of oxygen (6) at the inlet of the reaction unit (28) for partial oxidation in oxygen was 126 kg / h, which corresponds to an oxygenation rate of 0.52. The oxygenation rate is defined as the ratio of the molar flow rate of injected oxygen to the theoretical oxygen flow rate for the complete oxidation of all hydrocarbons present (methane, ethane, propane, butane, etc.). This ratio was adjusted to convert all methane and to limit or prevent the conversion of other molecules, especially CO.

[0169] With the same amount of treated flue gas as in Example 1, the production of hydrocarbon fraction is 230 kg / h instead of the previous 186 kg / h.

[0170] Table 2 summarizes the flow rates at the inlet and outlet of the unit of this process.

[0171] [Table 2]

[0172] Requirements: - Water electrolysis unit (5) consumption: 5.4 MWe; - Heat consumed by the RWGS reaction unit (8) at 864 °C: 0.17 MWth; - Heat required to preheat the RWGS unit feedstock ((3) + (35) + (7)) to 864°C: 0.7 MWth; - Steam to the reboiler of the carbon dioxide capture unit (2): 1025 kg / h; - Steam to the reboiler of the carbon dioxide capture unit (32): 330 kg / h.

[0173] Energy Recovery: - heat released by the reaction unit (28) due to partial oxidation in oxygen at 1200 ° C: 0.00 MWth; - steam generated in the heat exchanger (31): 1660 kg / h; - steam generated in the FT reaction unit (13): 1880 kg / h; - Power generation from the first turbine (26): 4.3 kWe. [Brief explanation of the drawings]

[0174] [Figure 1] 1 shows a schematic diagram of a device according to the invention.

Claims

1. 1. A device for capturing and converting a carbon dioxide-containing feedstock, comprising the following units: a unit (2) for capturing carbon dioxide from a feedstock (1); suitable for producing a carbon dioxide-rich effluent (3); a water electrolysis unit (5), suitable for converting water (4) to give oxygen (6) and hydrogen (7); a reverse water gas shift RWGS reaction unit (8) suitable for treating the carbon dioxide-rich effluent (3) with hydrogen (7) to produce a RWGS gas (9) enriched with carbon monoxide and water; a Fischer-Tropsch reaction unit (13), suitable for converting the RWGS gas (9) to produce a FT effluent (14); a first separation unit (15) suitable for at least partially treating the FT effluent (14) to give a hydrocarbon effluent (17), a first aqueous effluent (16) and a first gaseous effluent (33); a second separation unit (34) suitable for treating the first gaseous effluent (33) to produce a carbon dioxide-depleted gaseous effluent (18); the carbon dioxide-rich gaseous effluent (35) is sent at least in part to the RWGS reaction unit (8); a partial oxyfuel combustion reaction unit (28) suitable for partially oxidizing at least a portion of the carbon dioxide-depleted gaseous effluent (18) to produce an oxyfuel combustion effluent (29) comprising carbon monoxide and water; sending the oxyfuel combustion effluent (29) to a Fischer-Tropsch reaction unit (13); and a hydrogen reaction unit (20), suitable for treating the hydrocarbon effluent (17) to give at least one hydrocarbon fraction (21);

2. 2. The device of claim 1, wherein the partial oxyfuel combustion reaction unit (28) is adapted to generate heat that is used to provide thermal energy to the RWGS reaction unit (8) and / or the carbon dioxide capture unit (2).

3. 3. A device according to claim 1 or 2, wherein the partial oxyfuel combustion reaction unit (28) is suitable for producing heat used to provide thermal energy to the RWGS reaction unit (8).

4. 4. The device according to any one of claims 1 to 3, wherein the partial oxy-fuel combustion reaction unit (28) is suitable for heating the carbon dioxide rich effluent (3) and / or the carbon dioxide rich gaseous effluent (35) and / or the hydrogen (7) or for integrating the reaction section of the RWGS reaction unit (8) into the oxy-fuel combustion chamber.

5. 5. The device according to claim 1, wherein the Fischer-Tropsch reaction unit (13) is suitable for generating a first steam (22) for supplying thermal energy to the carbon dioxide capture unit (2).

6. 6. The device according to any one of claims 1 to 5, comprising a first heat exchanger (31), the first heat exchanger (31) being suitable for generating second steam (23) by heat exchange between water and RWGS gas (9).

7. The device of any one of claims 1 to 6, comprising a first turbine (26) that at least partially processes the carbon dioxide-depleted gaseous effluent (18) to generate electricity.

8. 8. The device of claim 7, wherein the electricity is used to provide thermal energy to the RWGS reaction unit (8) and / or the carbon dioxide capture unit (2) and / or the water electrolysis unit (5).

9. A device according to any one of claims 1 to 8, wherein the water electrolysis unit (5) treats water from the supply line and / or the RWGS gas (9) and / or the FT effluent (14).

10. The device according to any one of the preceding claims, wherein water from the RWGS gas (9) is at least partially separated by a third separation unit (10) and sent to the water electrolysis unit (5).

11. A device according to any one of the preceding claims, comprising a carbon dioxide separation unit located between the RWGS reaction unit (8) and the Fischer-Tropsch reaction unit (13).

12. 1. A method for capturing and converting carbon dioxide, comprising the steps of: - treating the feedstock (1) in a carbon dioxide capture unit (2); producing a carbon dioxide-rich effluent (3); - converting water (4) in a water electrolysis unit (5) to produce oxygen (6) and hydrogen (7); - treating the carbon dioxide rich effluent (3) with hydrogen (7) in a reverse water gas shift RWGS reaction unit (8) to produce a RWGS gas (9) enriched with CO and water; - converting the RWGS gas (9) in a Fischer-Tropsch reaction unit (13); producing a FT effluent (14); - treating the FT effluent (14) in a first separation unit (15); producing at least one hydrocarbon effluent (17), a first aqueous effluent (16) and a first gaseous effluent (33); - treating the first gaseous effluent (33) in a second separation unit (34) to produce a carbon dioxide-rich gaseous effluent (35) and a carbon dioxide-depleted gaseous effluent (18); - sending at least a portion of the carbon dioxide-rich gaseous effluent (35) to said RWGS reaction unit (8); - Partially oxidizing at least a portion (24) of the carbon dioxide-depleted gaseous effluent (18) in a partial oxyfuel combustion reaction unit (28), after optional expansion in a turbine (26), to produce an oxyfuel combustion effluent (29) comprising carbon monoxide and water; - sending the oxyfuel combustion effluent (29) to an FT reaction unit (13); and - treating the hydrocarbon effluent (17) in a hydrogen reaction unit (20); producing at least one hydrocarbon fraction (21).

13. 13. The method of claim 12, The RWGS reaction section (8) operates under the following operating conditions: the temperature is between 700°C and 1200°C, preferentially between 800°C and 1100°C, and even more preferentially between 850°C and 1050°C; the pressure is between 0.1 MPa and 10 MPa, preferentially between 0.1 MPa and 5 MPa, more preferentially between 0.1 MPa and 3.5 MPa; The gas space velocity is 5000 NL / kg at the inlet of the reactor. ｃａｔａ / h~40,000NL / kg ｃａｔａ / h; the catalyst comprises a metal or a combination of metals selected from the group consisting of the elements Ni, Cu, Fe, Co, Pt, Pd, Ru, Ag and Au; and / or The FT reaction unit (13) operates under the following operating conditions: the temperature is between 170°C and 280°C, preferably between 190°C and 260°C, preferentially between 210°C and 240°C; the absolute pressure is between 0.1 MPa and 6.0 MPa, preferably between 1.5 MPa and 3.5 MPa, and preferentially between 2.0 MPa and 3.0 MPa; the catalyst comprises cobalt or iron, preferably cobalt, and optionally a support, for example an alumina, silica, silica-alumina, siliceous alumina or titanium-based support; The reactor is provided with at least one reactor used under at least one of the following conditions:

14. 14. The method according to claim 12 or 13, wherein the partial oxyfuel combustion reaction unit (28) comprises at least one reactor operated under at least one of the following operating conditions: the absolute pressure is between 0.1 MPa and 9 MPa, preferably between 1 MPa and 4 MPa; the temperature is between 600°C and 2000°C, preferably between 800°C and 1700°C, preferably between 1100°C and 1500°C;

15. The method according to any one of claims 12 to 14, wherein the second separation unit (34) is a unit for separating carbon dioxide by membrane and / or by absorption in a solvent and / or by adsorption on a solid.

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