Production of synthetic fuels from carbon dioxide with carbon dioxide separation

Abstract

The present invention relates to a device / method for CO2 capture / conversion comprising / using a capture unit (2) for capturing CO2 from a feedstock (1) to produce a CO2-rich waste effluent (3), a water electrolysis unit (5) for converting water (4) to oxygen (6) and hydrogen (7), a RWGS reaction unit (8) for treating the CO2-rich effluent with hydrogen to produce a RWGS gas (9) rich in CO and water, a FT reaction unit (13) for converting the RWGS gas to a FT effluent (14), a first separation unit (15) for treating the FT effluent to produce a hydrocarbon effluent (17) and a gaseous effluent (33), a second separation unit (34) for separating the first gas (33) to produce a CO2-depleted gas (18) and sending the CO2-rich gas (35) to the RWGS unit, and a hydrogen reaction unit (21) for treating the hydrocarbon effluent to produce a hydrocarbon fraction (21).

Description

[Technical Field]

[0001] The present invention relates to the production of synthetic fuels, i.e., gasoline, kerosene, gas oil, and / or other hydrocarbon products, such as naphtha, or lubricating oil bases, of very high quality (essentially sulfur-, aromatics-, and nitrogen-free). More particularly, one object of the present invention is the production of 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 + H2, 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 reverse water gas shift (RWGS) conversion processes 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 is true for the Fischer-Tropsch synthesis process, which, depending on the catalyst and operating conditions, allows the synthesis gas to be converted into a mixture of paraffins and / or olefins. When paraffins are produced, it is desirable to improve certain of their properties to allow them to be used for 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 base for fuel, commonly known as e-fuel.

[0005] Reference may be made, for example, to patent application WO 02 / 04999, which describes a renewable Fischer-Tropsch synthesis process that allows the production of hydrocarbons and alcohols, residual carbon dioxide, and water from wind energy. The process comprises 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-tubular reactor. Various recycling options are described (e.g., recycling of unconverted carbon dioxide after separation from the RWGS, 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 thermal integration between the various thermal energy sources generated by the unit operations.

[0007] Patent application (Patent Document 2) relates to a method for the production of high-octane fuel from carbon dioxide and water. The raw materials are industrial carbon dioxide and water. The end product may 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, may be withdrawn 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 productivity.

[0009] Patent application (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 productivity.

[0011] Patent application (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 be partially catalytically reacted 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, the second of which processes unconverted synthesis gas from the first. There is no carbon dioxide recycle or water recycle.

[0012] Therefore, an analysis of the prior art shows that the sequence of operations 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 it is possible to produce hydrogen by electrolysis of water using an electrical source, e.g. solar or wind energy.

[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 primary object of this specification is to overcome the problems of the prior art and capture carbon dioxide and upgrade it into a form of synthetic fuel that can be used in means of transportation.

[0016] The present invention relates to the capture and conversion of carbon dioxide to produce CO+H2 synthesis gas and its conversion to synthetic hydrocarbons by a Fischer-Tropsch reaction. The characteristics of the effluent from the Fischer-Tropsch synthesis can be adjusted by post-treatment methods (upgrading processes) to make them 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 generating 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 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 is recycled to the inlet of the RWGS reaction section. Therefore, the gaseous effluent that can be sent to the air combustion section no longer contains substantially any carbon dioxide.

[0019] Preferably, the presence of an air combustion unit makes it possible to generate a gaseous effluent containing carbon dioxide, nitrogen, and water vapor. This is done by combustion of the gaseous hydrocarbon by-products of the process. Advantageously, the gaseous effluent can be returned to the inlet of the carbon dioxide capture unit to capture the carbon dioxide and then upgrade it in the RWGS reaction unit. Advantageously, the release of heat generated by the air combustion makes it possible 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.

[0020] The energy integration of this process also allows for the generation of electricity from heat recovery. This heat converted to electricity can provide energy for both the electrolysis of water and the RWGS reactor and / or capture unit that converts carbon dioxide and hydrogen to synthesis gas.

[0021] Advantageously, the hydrogen generated by water electrolysis can be used for carbon dioxide conversion, Fischer-Tropsch synthesis, and post-processing. Preferably, the hydrogen required in the process is entirely provided by the water electrolysis unit. Therefore, the process according to the invention does not require an external hydrogen supply, which can be generated, for example, by steam reforming of natural gas. The electrolysis device preferably runs on low-carbon electricity, which contributes to the renewable nature of the fuel and the resulting gas. In addition, the water used for hydrogen production can originate, at least in part, from recycled water generated in the various steps of the process, which has the advantage of limiting the external supply of water.

[0022] According to a first aspect, the above objects and other advantages are obtained by a device for capturing and converting a feedstock containing carbon dioxide, comprising the following units: - a unit for capturing carbon dioxide from the 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; - a water electrolysis unit, suitable for converting water to give oxygen and hydrogen; - a reverse water gas shift RWGS reaction unit; suitable for treating the carbon dioxide-rich effluent with hydrogen to produce a carbon monoxide and water-rich RWGS gas; - a Fischer-Tropsch reaction unit suitable for converting the RWGS gas and producing a FT effluent, optionally generating first water steam, for example 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, and a first gaseous effluent; the first aqueous effluent is optionally at least partially recycled to the inlet of the water electrolysis unit; a second separation unit suitable for treating the first gaseous effluent to produce a carbon dioxide-rich gaseous effluent and a carbon dioxide-depleted gaseous effluent; the carbon dioxide-rich gaseous effluent being sent at least in part to the RWGS reaction unit and the carbon dioxide-depleted gaseous effluent being optionally at least in part recycled to the 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 meeting specifications for transport use, for example.

[0023] According to one or more embodiments, the device comprises an air combustion reaction unit adapted to at least partially oxidize the carbon dioxide-depleted gaseous effluent to produce a combustion effluent comprising carbon dioxide and water, and directs the combustion effluent to a carbon dioxide capture unit.

[0024] According to one or more embodiments, the air-combustion reaction unit is suitable for generating heat that is used to supply thermal energy to the RWGS reaction unit and / or the carbon dioxide capture unit (via a feed line), for example, by heat exchange to heat the carbon dioxide-rich effluent and / or the carbon dioxide-rich gaseous effluent and / or hydrogen, or by integrating the reaction section of the RWGS reaction unit into the chamber of the air-combustion unit.

[0025] 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.

[0026] 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.

[0027] 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, which can be used, for example, to supply thermal energy to the carbon dioxide capture unit.

[0028] According to one or more embodiments, the device includes a first turbine that processes at least a portion of the carbon dioxide-depleted gaseous effluent separated by the first separation unit to generate electricity.

[0029] 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.

[0030] According to one or more embodiments, 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.

[0031] According to one or more embodiments, electricity is used to provide thermal energy to the regeneration section of the carbon dioxide capture unit.

[0032] According to one or more embodiments, the water electrolysis unit processes water from the make-up line and / or the RWGS gas and / or FT effluent.

[0033] According to one or more embodiments, water from the RWGS gas is at least partially or completely separated by a third separation unit and sent to a water electrolysis unit.

[0034] According to one or more embodiments, the carbon dioxide-rich effluent and / or the carbon dioxide-rich gaseous effluent are introduced into the RWGS reaction unit after purification, either separately or after mixing. In one or more embodiments, the RWGS gas is introduced into the Fischer-Tropsch reaction unit after purification, upstream or downstream of the third separation unit. According to 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 technologies for purifying gas are as follows: adsorption, absorption, and catalytic reaction.

[0035] 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.

[0036] According to a second aspect, the above objects, 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 to produce 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 to produce a CO and water rich RWGS gas; - converting the RWGS gas in a Fischer-Tropsch reaction unit to produce 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 to produce 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; - optionally oxidizing at least a portion of the carbon dioxide-depleted gaseous effluent in an air-combustion reaction unit, for example after expansion in a turbine, to produce a combustion effluent comprising carbon dioxide and water: - optionally sending the combustion effluent to a carbon dioxide capture unit; and - treating the hydrocarbon effluent in a hydrogen reaction unit to produce at least one hydrocarbon fraction to the required specifications, for example for transportation applications.

[0037] 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, 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 comprises one or a combination of metals selected from the group consisting of the elements 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, based on alumina, silica, silica-alumina, siliceous alumina.

[0038] 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 and iron, preferably cobalt, and optionally a support, for example based on alumina, silica, silica-alumina, siliceous alumina or titanium.

[0039] According to one or more embodiments, the air-fired reaction unit comprises at least one reactor operated under at least one of the following operating conditions: - Absolute pressure is 0.1MPa~4MPa; the temperature is between 600°C and 2000°C, preferably between 800°C and 1800°C, preferentially between 900°C and 1500°C; - There is air used for combustion, the air permeability being between 1 and 2, preferably at least 1.2, the air permeability being defined as the ratio of the molar flow rate of the injected air to the theoretical air flow rate for complete oxidation of all fuels.

[0040] According to one or more embodiments, the second separation unit is a unit for separating carbon dioxide by membrane and / or absorption in a solvent and / or adsorption on a solid.

[0041] 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, with reference to the following drawings, in which: DETAILED DESCRIPTION OF THE INVENTION

[0042] (List of drawings) FIG. 1 shows a schematic representation of a device according to the invention, including a second separation unit for producing a carbon dioxide-rich gaseous effluent, which is sent to a RWGS reaction unit.

[0043] (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.

[0044] In the present description, the term "to comprise" is synonymous with (meaning identical to) "to include" and "to contain," is inclusive or open-ended, and does not exclude other elements not specified. The term "to comprise" is understood to include the exclusive and closed-ended term "to consist of." Furthermore, in the present description, an effluent comprising essentially or solely 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.

[0045] In this description, the term "physical solvent" is synonymous with (means the same thing as) a solvent that forms weak bonds with the solute (e.g., hydrogen bonds, van der Waals bonds) or a solvent that does not form strong bonds with the solute (e.g., covalent bonds, ionic bonds).

[0046] The present invention can be defined as a device and method comprising the operation of a series of units for producing synthetic hydrocarbons, such as gasoline, kerosene, gas oil and / or naphtha or lubricating oil bases, preferably of very high quality, from carbon dioxide from a capture unit.

[0047] The devices and methods according to the invention are characterized in that they contain and use, 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 hydrotreating (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 an optional unit for combustion of the gaseous hydrocarbon by-products of the process (RWGS and Fischer-Tropsch synthesis and post-treatment) after the carbon dioxide has been separated therefrom. Advantageously, the required hydrogen can be produced by a water electrolysis unit, and the water can originate from the RWGS and Fischer-Tropsch reaction units.

[0048] One of the features of the present invention can be summarized by the use of carbon dioxide for the production of synthetic fuels, gasoline, kerosene, gas oil and / or naphtha or very high quality lubricating oil base. The present invention is also based on the presence of a carbon dioxide separation unit for extracting and recycling carbon dioxide from other gaseous effluent by-products of the process.

[0049] An air combustion unit may be advantageously provided to process the carbon dioxide depleted gaseous hydrocarbon by-product to produce a carbon dioxide rich gaseous effluent to improve production of the product of interest.

[0050] Additionally, the release of heat generated by combustion can advantageously be used to provide thermal energy to the RWGS reaction unit (8) and / or the carbon dioxide capture unit (2). This input of thermal energy can be done, for example, by heat exchange with: - combustion gases in the combustion chamber; and / or - Hot gaseous effluent downstream of the combustion chamber; and / or - Water vapor generated by the air-fired reaction unit and / or by heat exchange with the gaseous combustion 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., carbon dioxide complexed with amines, 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 steam (e.g. produced at the outlet of the Fischer-Tropsch reaction unit and / or the RWGS reaction unit), which electricity can, for example, supply thermal energy to a device according to the invention, e.g. an RWGS reaction unit.

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

[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 a Fischer-Tropsch (FT) effluent (14) and, optionally, for generating a first steam (22); the first steam (22) is 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 produce at least: a hydrocarbon effluent (17), a first gaseous effluent (33) (off-gas), and a first aqueous effluent (16), a product of the Fischer-Tropsch synthesis obtained from the condensation of 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); - optionally an air 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 a combustion effluent (29) containing carbon dioxide and water; sending the combustion effluent (29) to a carbon dioxide capture unit (2); a hydrogen reaction unit (20) (hydrotreating and / or hydrocracking and / or hydroisomerization unit) suitable for treating the hydrocarbon effluent (17) with hydrogen (7) to separate at least one hydrocarbon fraction (21), the hydrocarbon fraction (21) comprising, for example, 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); the RWGS gas (12) is depleted in water (compared to the RWGS gas (9)), which is sent to the FT reaction unit (13) instead of the RWGS gas (9), sending a 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. Advantageously, the use of water vapor 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 facility.

[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 heat exchanger (31) for generating steam has not been described in detail. The same applies to the water outlet from the carbon dioxide capture unit (2).

[0058] (Carbon dioxide capture unit) A 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 supply of CO2 as conventional. The CO2 can be 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 exhaust 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 include a direct air capture (DAC) device.

[0062] For the capture, several agents can be used, for example 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, for example 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 transition of chemical species from gas to liquid. The gas containing the impurities or species to be separated is sent to a column where it is contacted with a liquid solvent, and the two streams can be used in various hydrodynamic configurations (cocurrent, cross-flow, or countercurrent; the latter solution is preferred for reasons of favorable thermodynamic equilibrium). This absorption is carried out with an absorbent solution, which includes a chemical or physical solvent, the distinction relating to whether there is a chemical reaction between the absorbed components and the solvent.

[0064] Physical absorption is preferred with a view to minimizing the energy costs of the process; it is particularly suitable in cases where the partial pressure of the species to be separated is high.

[0065] Chemical absorption is preferred in cases where the dilution and partial pressure of the species to be separated are high and / or where 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 at the time of scrubbing. Therefore, for the capture of carbon dioxide from (industrial) exhaust gases with low carbon dioxide concentration values, typically 3% to 15% by volume (typically in gases at low pressure), scrubbing by chemical absorption, for example with amine solvents, for example of the alkanolamine type, is highly suitable.

[0066] The absorbent solutions commonly used today are aqueous solutions containing one or more reactive compounds or having physicochemical affinity for acid compounds. The reactive compounds can be, for example, but not limited to, amines (primary, secondary, or 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 having amine groups and whose structures are 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 an acid-base equilibrium: low temperatures favor the reaction between the basic amine and the acidic carbon dioxide, while high temperatures favor the reverse reaction. Therefore, the amine process, for example, uses an aqueous phase containing 20-50% by weight of one or more amines. Two columns (not shown) can be used, in 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 flows through the column, capturing carbon dioxide. At the bottom of the column, the amine solvent (the "rich" solvent) reaches a predetermined loading rate (the ratio between the moles of captured carbon dioxide and the moles of amine); at the top of the column, the gaseous stream itself exits with a predetermined specification. That is, the carbon dioxide content is, for example, nearly 10 times lower than the initial content in the exhaust gas. The rich solvent is sent to a second column called the regenerator, the operation of which is similar to that of a distillation column, but operated at a higher temperature. The regenerated amine solvent ("lean" solvent) can itself be sent back to the absorber. The amine solvent therefore flows continuously from one column to the other in a closed loop, preferably passing 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 of 90°C to 250°C, preferably 110°C to 240°C, and highly preferably 120°C to 200°C at the bottom of the column.

[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 waste gases is the regeneration of the separating agent. Depending on the type of absorption (physical and / or chemical), regeneration by expansion and / or distillation and / or entrainment with vaporized gases known as "stripping gases" is generally envisaged.

[0072] One of the major limitations of commonly used solvents 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 accounts for 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 to 4 GJ / t per ton of captured carbon dioxide. New capture methods tend to reduce this energy, leading to values ​​below 2 GJ / t per ton of carbon dioxide. In the context of air treatment, the concentration of carbon dioxide is very low, so the energy consumed is very high, on the order of 5 GJ / t to 7.5 GJ / t per ton of carbon dioxide.

[0073] Another possible embodiment is based on the principle of adsorption by a solid adsorbent that has 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 progresses through the bed of solids, and at the outlet, the stream contains no or 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 a regeneration operation: - Temperature-elevated 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 in the presence of a gas to promote desorption).

[0074] An obstacle 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 obstacle.

[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 amine impregnation, metal-organic framework (MOF) solids, and supported alkali metal carbonates. These solid adsorbents are increasingly being used for the capture of carbon dioxide from air. In these cases, the energy required for regeneration of the adsorbent by physical adsorption on zeolites, for example, is on the order of 0.6-0.9 GJ / t of carbon dioxide by weight (t). For 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 input of energy into the carbon dioxide capture unit (2) allows the energy efficiency of the process to be maximized.

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

[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 pretreatment section, which is suitable for extracting oxygen-containing compounds from the water (4), e.g., 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 electrolyzer: - 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 contains 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 contains 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) film; - the electrode contains 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) comprises 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 (after drying) 99.5% to 99.999% H by weight.

[0084] 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, which is at least partially supplied by the first steam source (22) and possibly by the second steam source (23). This input of energy into the electrolysis unit (5) makes it possible to improve the energy efficiency of the process.

[0085] (RWGS reaction unit) The RWGS reaction unit (8) produces RWGS gas (9) (synthesis gas), which is CO-rich (and hydrogen-depleted) compared to the carbon dioxide-rich effluents (3) and (35) and contains unconverted carbon dioxide and water. The hydrogen (7) required for the RWGS reaction comes from the water electrolysis unit (5).

[0086] According to one or more embodiments, the RWGS reaction unit (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, such as one based on alumina, silica, silica-alumina or siliceous alumina.

[0087] 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) is compatible with the requirements of the FT unit, i.e., between 0.5 and 4, preferably between 1 and 3, more preferably between 1.5 and 2.5.

[0088] 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.

[0089] 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) via a first heat exchanger (31) that generates second steam (23) by (indirect) heat exchange between water (not shown) and the RWGS gas (9), or preferably directly at the outlet of the RWGS reaction unit (8).

[0090] The RWGS gas (9) is preferably sent to a third separation unit (10).

[0091] (Fischer-Tropsch Reaction Unit) According to the present invention, in the FT reaction unit (13), the carbon monoxide and hydrogen present in the RWGS gas (9) (preferably depleted of water) react to produce a stream comprising the FT effluent (14), which comprises unconverted synthesis gas, carbon dioxide, gaseous and liquid hydrocarbon products, and the FT effluent (14) comprising water.

[0092] According to one or more embodiments, the RWGS gas (9) (preferably depleted in water) 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, for example by an optional hydrogen feed, so that the H2 / CO molar ratio is as defined above.

[0093] 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-tube fixed bed reactors, or one or more slurry bubble column reactors, or one or more microchannel reactors.

[0094] According to one or more embodiments, the FT reaction unit employs one or more bubble column reactors. Because the synthesis is highly exothermic, this embodiment allows, among other things, for improved reactor heat control and the creation of very little pressure drop.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] According to one or more embodiments, the FT reaction unit (13) is suitable for generating a first steam (22) and supplying thermal 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). This heat exchanger allows for the removal of thermal energy from the exothermic Fischer-Tropsch reaction.

[0099] (First Separation Unit) In the first separation unit (15), at least one (first) portion of the FT effluent (14) is treated to produce: - Hydrocarbon spill (17) (drastically reduced water content compared to FT spill (14)), a first gaseous effluent (33), and - a first aqueous effluent (16).

[0100] 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.

[0101] 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.

[0102] According to one or more embodiments, the hydrocarbon effluent (17) comprises: n-paraffins, olefins, and oxygenated compounds resulting from condensation of the gaseous effluent under the operating conditions of the Fischer-Tropsch reaction.

[0103] 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.

[0104] According to one or more embodiments, the first aqueous effluent (16) is generated from a Fischer-Tropsch synthesis resulting from the condensation of gaseous water under the operating conditions of the Fischer-Tropsch reaction.

[0105] 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.

[0106] (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); which is rich in carbon dioxide relative to the carbon dioxide content of the first effluent (33).

[0107] According to a first embodiment, the second separation unit (34) is a membrane separation unit. Membrane separation methods were not widely recommended for post-combustion carbon dioxide capture initially, as the method of gas-liquid absorption in chemical solvents was considered the most mature and most 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 following review article: Oil Gas Sci. Technol. - Rev. IFP Energies nouvelles, Volume 69, Number 6, November-December 2014. The main performances are the capture rate and a carbon dioxide purity of more than 90%.

[0108] 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.

[0109] According to a third embodiment, the second separation unit (34) is a carbon dioxide capture unit based on the adsorption of carbon dioxide on a solid.

[0110] 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.

[0111] According to one or more embodiments, at least a (second) portion (24) of the carbon dioxide-depleted gaseous effluent (18) is processed by a first turbine (26) to generate electricity; gases (27) leaving the first turbine (26) are sent to an air-fired reaction unit (28).

[0112] 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.

[0113] 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, a unit of the following type: - Partial oxidation (POx); - Steam methane reforming (SMR); - Autothermal reforming (ATR); - Enhanced Heat Transfer Reforming (EHTR).

[0114] 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).

[0115] (Air Combustion Reaction Unit) According to one or more embodiments, at least a portion (24) of the carbon dioxide-depleted gaseous effluent (18) is sent to an air-combustion reaction unit (28) where the hydrocarbon compounds, carbon monoxide, and hydrogen present (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 air (30), producing combustion gases that (e.g., substantially) comprise carbon dioxide and water.

[0116] According to one or more embodiments, the air-fired reaction unit (28) includes at least one reactor operating under at least one of the following operating conditions: - Absolute pressure is 0.1MPa~4MPa; the temperature is between 600°C and 2000°C, preferably between 800°C and 1800°C, preferentially between 900°C and 1500°C; - Air (30) is present, the aeration rate being between 1 and 2, preferably at least 1.2, in order to limit in particular the concentration of unburned CO and H2 gases.

[0117] The permeability is defined as the ratio of the molar flow rate of injected air to the theoretical air flow rate for complete oxidation of all fuels.

[0118] 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 an air-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.

[0119] According to one or more embodiments, the temperature of the combustion gases produced in the air-combustion reaction unit (28) is between 600°C and 2000°C, preferably between 800°C and 1800°C, preferentially between 900°C and 1500°C, and the absolute pressure is between 0.1 MPa and 4 MPa.

[0120] The combustion gases produced in the air-fired reaction unit (28) are at a high temperature and can provide part of the required thermal energy to the RWGS reaction unit (8) and / or the carbon dioxide capture unit (2) via a feed line (32).

[0121] According to one or more embodiments, the air-combustion reaction unit (28) is suitable for generating heat that is used to supply thermal energy to the RWGS reaction unit (8) and / or the carbon dioxide capture unit (2) (via the feed line (32)), e.g., by heat exchange, to heat the carbon dioxide-rich effluent (3) and / or the carbon dioxide-rich gaseous effluent (35) and / or hydrogen (7), or for integrating the reaction section of the RWGS reaction unit (8) into the chamber of the air-combustion unit (28).

[0122] The thermal energy may be provided, for example, by heat exchange with water vapor produced by the air-fired reaction unit (28) and / or within the combustion chamber of the air-fired reaction unit (28) and / or with hot gaseous effluent downstream of the air-fired reaction unit (28). For example, after the transfer of thermal energy from the combustion gases in the combustion chamber to, for example, the RWGS reaction (8), the residual heat contained in the combustion effluent (29) can be used to generate water vapor at the outlet of the air-fired reaction unit (28), which can be sent, for example, to the carbon dioxide capture unit (2).

[0123] Advantageously, the air combustion reaction unit (28) allows for the conversion of substantially all of the hydrocarbon by-products of the process to carbon dioxide, thus upgrading them into desired products, thereby improving the yield of the desired products of the process according to the invention.

[0124] The combustion effluent (29) at the outlet of the air-fired reaction unit (28) is recycled to the inlet of the carbon dioxide capture unit (2).

[0125] (Hydrogen reaction unit) The hydrocarbon effluent (17) is sent to a hydrogen reaction unit (20) where it undergoes hydrotreating and / or hydrocracking and / or hydroisomerization reactions to produce one or more hydrocarbon fractions (21) that can be upgraded, in particular to synthetic fuels, i.e., gasoline, kerosene, gas oil, and / or other hydrocarbon products, such as naphtha, or lubricating oil bases, of very high quality (substantially sulfur-, aromatics-, and nitrogen-free). One possible option is the production of paraffinic fractions, base products for petrochemical processes, e.g., C10-C13 fractions for the production of linear alkylbenzenes (LAB), or waxes for various industrial applications.

[0126] According to one or more embodiments, the hydrogen reaction unit (20) comprises at least one reactor 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 , more preferentially 0.5h ?1 ~5h ?1 is; the hydrogen flow rate is between 100 and 2000 standard liters of hydrogen per liter of volume of feedstock and per hour, preferably between 150 and 1500 standard liters of hydrogen per liter of volume of feedstock and more preferentially between 300 and 1500 standard liters of hydrogen per liter of volume of feedstock.

[0127] 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 that is capable of releasing one or more protons, and optionally a binder.

[0128] 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, employed alone or in mixtures, and preferably selected from platinum and palladium, employed alone or in mixtures, and preferably used in their reduced form.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] According to one or more embodiments, the hydrotreating and / or hydrocracking and / or hydroisomerization catalyst comprises or consists of at least one noble metal, a support comprising or consisting of at least one zeolite, and at least one binder.

[0134] 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.

[0135] (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).

[0136] According to one or more embodiments, the water-depleted RWGS gas (12) contains less than 1 mol% water, preferably less than 0.5 mol% water, and highly preferably less than 0.25 mol% water.

[0137] The water-depleted RWGS gas (12) is sent to the FT reaction unit (13).

[0138] (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).

[0139] 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.

[0140] According to one or more embodiments, a second turbine (not shown) is adapted to at least partially process the first steam (22) and / or the second steam (23) to produce electricity (not shown).

[0141] 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 to preheat the feedstock for the RWGS reaction unit (8).

[0142] (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).

[0143] 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.

[0144] According to one or more embodiments, the carbon dioxide separation unit is located at the outlet of the FT reaction unit (13).

[0145] (oxyfuel combustion unit) According to one or more embodiments, the oxygen (6) obtained from the water electrolysis unit is upgraded in an oxyfuel combustion (partial or complete oxidation) unit, for example to convert the formed methane present in the RWGS gas (9) separated by the carbon dioxide separation unit.

[0146] (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) after purification, upstream or downstream of the third separation unit (10). 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: adsorption, absorption, and catalytic reaction.

[0147] In this patent application, 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), e.g., 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.

[0148] (Example) The various examples relate to arrangements according to the invention or not, the object of which is to produce a hydrocarbon fraction from an exhaust gas containing 21% by weight of carbon dioxide. The flow rate of the exhaust gas to be treated is 3641 kg / h for all examples.

[0149] (Example 1; not in accordance with the present invention) An embodiment of the device in accordance with the present invention is similar to the device shown in FIG. 1 except that there is no second separation unit (34) and therefore no carbon dioxide-rich gaseous effluent (35) directed toward the RWGS reaction unit (8).

[0150] This example illustrates the operation of the sequence with upgrading a portion (24) of the carbon dioxide-depleted gaseous effluent (18) from the first separation unit (15) by a combustion process to generate heat for the RWGS reaction unit (8). Carbon dioxide present in the carbon dioxide-depleted gaseous effluent (18) prior to entering the air-fired reaction unit (28) is not separated.

[0151] The exhaust gas flow rate feeding the carbon dioxide capture unit (2) is 3641 kg / h, to which must be added the exhaust gas flow rate of the combustion effluent (29), giving a total flow rate of 5509 kg / h for the feedstock (1). The carbon dioxide-rich effluent (3) from the carbon dioxide capture unit (2) has a flow rate of 1283 kg / h and is sent to the RWGS reaction unit (8).

[0152] 1331 kg / h of water (4) is fed to the water electrolysis unit (5), of which 672 kg / h is fresh water. The power consumption of the water electrolysis unit (5) is 5.8 MWe.

[0153] The amount of primary steam (22) produced by the FT reaction unit (13) is 1310 kg / h. The heat exchanger (31) produces 1295 kg / h of secondary steam (23) out of the 2103 kg / h required for the operation of the carbon dioxide capture unit (2). The reboiler steam requirement of the carbon dioxide capture unit (2) is met.

[0154] The production of hydrocarbon fraction (21) is 177 kg / h.

[0155] Table 1 summarizes the flow rates at the inlet and outlet of the unit of the process.

[0156] [Table 1]

[0157] Requirements: - Water electrolysis unit (5) consumption: 5.8 MWe; - Heat consumed by the RWGS reaction unit (8) at 864 ° C: 0.2 MWth; - heat required to preheat the feedstock ((3) + (7)) at the inlet of unit (8) to 864°C: 0.8 MWth; - Steam to the reboiler of the carbon dioxide capture unit (2): 2103 kg / h. Energy Recovery: - heat released by the air combustion reaction unit (28) at 1200°C (with 20% excess air): 0.35 MWth; - heat recovered during the cooling of the exhaust gases at the outlet of the air-fired reaction unit (28) from 1200°C to 150°C: 0.7 MWth (preheating the feedstock (3) + (7)) at the inlet of the unit (8); - steam generated at the heat exchanger (31): 1295 kg / h; - steam generated in the FT reaction unit (13): 1310 kg / h; - Electricity generation at the first turbine (26): 5 kWe.

[0158] (Example 2: corresponds to Figure 1) Example 2 is in accordance with the present invention and is in accordance with Figure 1. This example illustrates the operation of a sequence with the upgrade of a portion (24) of the carbon dioxide-depleted gaseous effluent (18) to an air combustion unit that generates heat for the RWGS reaction unit (8). The carbon dioxide-depleted gaseous effluent (18) is obtained from a second separation unit (34), which makes it possible to remove 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 directed to the combustion unit.

[0159] The exhaust gas flow rate fed to the carbon dioxide capture unit (2) is 3641 kg / h, to which must be added the exhaust gas flow rate of the combustion effluent (29), giving a total flow rate of 5332 kg / h of the 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) to give a total flow rate of 1352 kg / h, which is sent to the RWGS reaction unit (8).

[0160] 1403 kg / h of water (4) is fed to the water electrolysis unit (5), of which 708 kg / h is fresh water. The power consumption of the water electrolysis unit (5) is 6.6 MWe.

[0161] The amount of first steam (22) produced by the FT reaction unit (13) is 1377 kg / h. The heat exchanger (31) produces 1332 kg / h of second steam (23) out of 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 reboiler of the carbon dioxide capture unit (2) and the second separation unit (34) are met.

[0162] With the same amount of treated exhaust gas as in Example 1, the production of hydrocarbon fraction (21) is 186 kg / h instead of the previous 177 kg / h.

[0163] Table 2 summarizes the flow rates at the inlet and outlet of the unit of the process.

[0164] [Table 2]

[0165] Requirements: - Consumption of water electrolysis unit (5): 6.6 MWe; - Heat consumed by the RWGS reaction unit (8) at 864 ° C: 0.2 MWth; - heat required to preheat the feedstock ((3) + (35) + (7)) at the inlet of unit (8) 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.

[0166] Energy Recovery: - heat released by the air-combustion reaction unit (28) at 1200°C (with 20% excess air): 0.56 MWth; - heat recovered during the cooling of the exhaust gases at the outlet of the air-fired reaction unit (28) from 1200°C to 150°C: 0.7 MWth (preheating the feedstock (3) + (35) + (7)) at the inlet of the unit (8); - steam generated at the heat exchanger (31): 1332 kg / h; - steam generated in the FT reaction unit (13): 1377 kg / h; - Power generation at the first turbine (26): 3.5 kWe. [Brief explanation of the drawings]

[0167] [Figure 1] 1 shows a schematic representation 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 carbon monoxide and water rich RWGS gas (9); 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 treating at least a portion of 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) and a carbon dioxide-rich gaseous effluent (35); the carbon dioxide-rich gaseous effluent (35) is at least partially sent to the RWGS reaction unit (8); 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, further comprising an air-combustion reaction unit (28) adapted to at least partially oxidize the carbon dioxide-depleted gaseous effluent (18) to produce a combustion effluent (29) comprising carbon dioxide and water, and sending the combustion effluent (29) to the carbon dioxide capture unit (2).

3. 3. The device according to claim 1 or 2, wherein the air combustion reaction unit (28) is suitable for producing heat used to provide thermal energy to the RWGS reaction unit (8) and / or the carbon dioxide capture unit (2).

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

5. 5. The device according to claim 2, wherein the air-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 combustion chamber.

6. 6. The device according to any one of claims 1 to 5, 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).

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

8. A device according to any one of claims 1 to 7, including a first turbine (26) for at least partially processing the carbon dioxide-depleted gaseous effluent (18) to generate electricity.

9. 9. The device according to claim 8, 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).

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

11. A device according to any one of claims 1 to 10, wherein water from the RWGS gas (9) is partially or completely separated by a third separation unit (10) and sent to the water electrolysis unit (5).

12. 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).

13. 1. A method for capturing and converting carbon dioxide, comprising the steps of: - treating the feedstock (1) in a carbon dioxide capture unit (2) to produce a carbon dioxide-rich effluent (3); - water (4) is converted 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 CO and water rich RWGS gas (9); - converting the RWGS gas (9) in a Fischer-Tropsch reaction unit (13) to produce a FT effluent (14); - treating the FT effluent (14) in a first separation unit (15) to produce at least one hydrocarbon effluent (17), a first aqueous effluent (16) and a first gaseous effluent (33); - separating 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); - at least partially passing the carbon dioxide-rich gaseous effluent (35) to the RWGS reaction unit (8); and - treating the hydrocarbon effluent (17) in a hydrogen reaction unit (20) to produce at least one hydrocarbon fraction (21);

14. 14. The method of claim 13, The RWGS reaction unit (8) operates under the following operating conditions: the temperature is between 700°C and 1200°C; the pressure is between 0.1 MPa and 10 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 at least one metal 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; the absolute pressure is between 1.0 MPa and 6.0 MPa; - The catalyst contains cobalt or iron The reactor is provided with at least one reactor used under at least one of the following conditions:

15. 15. The method according to claim 13 or 14, wherein the air-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 4 MPa; the temperature is between 600°C and 2000°C; - There is air used for combustion, the air permeability is between 1 and 2, the air permeability being defined as the ratio of the molar flow rate of the injected air to the theoretical air flow rate for complete oxidation of all fuels.

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