Production of synthetic fuels from carbon dioxide with partial or total oxy-combustion of by-products

Abstract

Device and method for CO2 capture / conversion, comprising / using a CO2 capture unit (2) from the feedstock (1) producing a CO2-rich effluent (3), a water electrolysis unit (5) converting water (4) into oxygen (6) and hydrogen (7), an RWGS reaction unit (8) treating the CO2-rich effluent with hydrogen and producing CO2- and water-enriched RWGS gas (9), an FT reaction unit (13) converting the RWGS gas and producing FT effluent (14), a first separation unit (15) treating the FT effluent and producing hydrocarbon effluent (17), a first water effluent (16) and a gaseous effluent (18), a partial or total oxy-combustion reaction unit (28) oxidizing the gaseous effluent and producing oxy-combustion effluent (29) sent to the capture unit, a unit hydrogen reaction (20) treating the hydrocarbon effluent to produce at least one hydrocarbon cut (21). Figure 1 to be published

Description

Title of the invention: Production of synthetic fuels from carbon dioxide with partial or total oxycombustion of by-products technical field

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

[0002] The capture and conversion of carbon dioxide into a fuel base according to the invention comprises two successive steps: the conversion of carbon dioxide and hydrogen into synthesis gas composed mainly of CO+H2, and then the conversion of the synthesis gas into synthetic hydrocarbons by the Fischer-Tropsch (FT) process. The properties of the products obtained from the Fischer-Tropsch process can be adjusted by suitable post-treatment operations to obtain the desired fuel specifications. Previous technique

[0003] The use of the reverse water-gas shift (RWGS) process for converting a mixture of carbon dioxide and hydrogen into synthesis gas (CO+H2) 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 converts said synthesis gas into a mixture of paraffins and / or olefins, depending on the catalyst and operating conditions. When paraffins are produced, it is preferable to improve certain properties to make them suitable for transportation applications.

[0004] Sequences of unit operations have been the subject of patent applications; these sequences of unit operations aim to convert carbon dioxide into a base for fuels, often known as e-fuels.

[0005] For example, one can cite US patent application 2010 / 0280135 A1, which describes a renewable Fischer-Tropsch synthesis process for producing hydrocarbons and alcohols from wind energy, residual carbon dioxide, and water. The process comprises the following unit operations: electrolysis of water to produce hydrogen and oxygen, an RWGS reactor for the production of synthesis gas, and Fischer-Tropsch synthesis in a high-temperature multitubular reactor. temperature. Various recycling options are described (e.g., recycle after separation of unconverted carbon dioxide from RWGS, recycle carbon dioxide ex-FT to RWGS, recycle of unconverted H2 and CO ex-FT to FT).

[0006] In contrast, patent application US2010 / 0280135 A1 does not mention the possibility of advantageously integrating the unit operations with a carbon dioxide capture process. Nor does it mention thermal integration between the different heat sources generated by the unit operations.

[0007] US patent application 2007 / 0244208 A1 relates to a process for producing high-octane fuel 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 mixtures of liquid hydrocarbons suitable for powering conventional combustion engines, or hydrocarbons suitable for further industrial processing or commercial use. Products such as dimethyl ether or methanol can also be removed from the production line. The heat generated by the exothermic reactions in the process is fully utilized, as is the heat generated by the production process itself, and also the heat produced by reprocessing hydrocarbons unsuitable for liquid fuel.

[0008] In contrast, US patent 2007 / 0244208 A1 does not mention the possibility of advantageously integrating unit operations with a carbon dioxide capture process. Nor does it mention recycling from the Fischer-Tropsch reactor to maximize fuel production.

[0009] US patent application 2012 / 0079767 A1 describes a process and system for producing synthesis gas by combining hydrogen and carbon monoxide from separate sources while controlling the molar ratio (H2 / CO) of the synthesis gas produced. The hydrogen is produced by water electrolysis. The carbon monoxide is produced by reacting carbon dioxide captured from the exhaust gases of stationary combustion engines with hydrogen in an RWGS reactor. Hydrocarbon fuels are produced from the synthesis gas by Fischer-Tropsch synthesis.

[0010] In contrast, US patent application 2012 / 0079767 A1 does not mention the possibility of advantageously integrating unit operations with a carbon dioxide capture process. Nor does it mention recycling from the Fischer-Tropsch reactor to maximize fuel production.

[0011] US patent application 2007 / 0142481 A1 describes a process for the synthesis of hydrocarbons comprising the introduction of hydrogen and carbon monoxide into a first stage of a Fischer-Tropsch reaction, allowing the hydrogen and carbon monoxide to react partially in a catalytic manner to form Hydrocarbons. At least a portion of a tail gas, comprising unreacted hydrogen and carbon monoxide, obtained from the first reaction step, is introduced into a second Fischer-Tropsch reaction step, which is a two-phase, high-temperature catalytic Fischer-Tropsch reaction step. The hydrogen and carbon monoxide can at least partially react catalytically in the second reaction step to form gaseous hydrocarbons. This patent application is characterized by the presence of two Fischer-Tropsch reactors in series; the second reactor processes the unconverted synthesis gas from the first. There is no carbon dioxide recycling or water recycling.

[0012] Thus, the analysis of the prior art highlights that the sequence of unit operations of RWGS and Fischer-Tropsch makes it possible to produce synthetic bases for fuels from carbon dioxide and hydrogen, said hydrogen being able in some cases to be produced by electrolysis of water with a source of electricity such as solar or wind.

[0013] However, these documents do not provide any information regarding the possibility of integrating unit operations into the process of producing synthetic fuels from carbon dioxide with an unexpected positive result. Summary of the invention

[0014] In the context described above, a first object of the present description is to overcome the problems of the prior art and to capture and valorize carbon dioxide in the form of synthetic fuels usable for transport applications.

[0015] The invention relates to the capture and conversion of carbon dioxide to produce a synthesis gas CO+H2, and to the conversion of said synthesis gas into synthetic hydrocarbons by the Fischer-Tropsch reaction. The characteristics of the effluents from the Fischer-Tropsch synthesis can then be adjusted by a post-treatment process (known to those skilled in the art) to make them compatible for use as fuels for land, air, and marine applications. The gases produced at the outlet of the Fischer-Tropsch reactor can also be upgraded to synthetic methane (e-methane), synthetic natural gas SNG (e-SNG), or LPG (e-LPG).

[0016] Specifically, the present invention relates to a device and a method for producing synthetic fuels from carbon dioxide and hydrogen, enabling improved production of products of interest. Advantageously, the method also makes it possible, through an original thermal integration, to minimize the energy requirements for the production of said fuels.

[0017] The present invention is based on the presence of a partial oxycombustion unit (known as "POX" for Pure Oxygen Oxidation, under substoichiometry to produce an H2 / CO mixture) or total, which produces a gaseous effluent comprising carbon dioxide, nitrogen, and water vapor, by oxy-combustion of the gaseous hydrocarbon by-products of the process. Advantageously, the gaseous effluent is returned to the inlet of the RWGS reaction unit, allowing for the recovery of additional carbon dioxide within the RWGS reaction unit. Advantageously, since the gaseous effluent exiting the oxy-combustion unit is at a high temperature, its introduction into the RWGS reaction unit limits the external heat input required for the RWGS reaction unit.

[0018] Advantageously, additional energy integration of the process makes it possible to use the heat released generated in the oxycombustion unit to supply calories to other units of the process, such as the RWGS reaction unit and / or the carbon dioxide capture unit, which limits the external supply of calories required.

[0019] The energy integration of the process also makes it possible to produce electricity from heat recovery. This heat, converted into electricity, provides energy both for the water electrolysis and / or for the RWGS reactor and / or the capture unit which converts carbon dioxide and hydrogen into synthesis gas.

[0020] Advantageously, hydrogen produced by water electrolysis can be used for carbon dioxide conversion, Fischer-Tropsch synthesis, and post-treatment. Preferably, the hydrogen required in the process is entirely supplied by a water electrolysis unit. Thus, the process according to the invention does not require an external supply of hydrogen, for example, produced by steam reforming of natural gas. The electrolyzer will preferably operate using low-carbon electricity, which will contribute to the renewable nature of the fuels and gases produced. Furthermore, the water used for hydrogen production can come, at least in part, from recycling the water produced in the various stages of the process, which has the advantage of limiting the external water supply.

[0021] Advantageously, the oxygen produced by the electrolysis of water can supply the partial or total oxycombustion section.

[0022] According to a first aspect, the aforementioned objects, as well as other advantages, are obtained by a device for capturing and converting a charge containing carbon dioxide, comprising the following units: - a carbon dioxide capture unit for the feed, for example using at least one amine-based solvent, at least one physical solvent such as, for example, polyethylene glycol dimethyl ether-based, and / or physical adsorption equipment operating by alternating temperature adsorption, and being adapted to produce an effluent rich in carbon dioxide; - a water electrolysis unit adapted to convert water to produce oxygen and hydrogen; - a reverse RWGS gas-to-water conversion reaction unit adapted to treat carbon dioxide-rich effluent with hydrogen and produce RWGS gas enriched in carbon monoxide and water; - a Fischer-Tropsch reaction unit adapted to: convert RWGS gas and produce an FT effluent, and optionally generate a first water vapor, generated for example by the vaporization of water in an exchanger located inside the Fischer-Tropsch reaction unit, to supply thermal energy to the carbon dioxide capture unit; - a first separation unit adapted to treat at least part of the FT effluent and produce: a hydrocarbon effluent, a first water effluent optionally recycled at least in part at the inlet of the water electrolysis unit, and a gaseous effluent optionally recycled in part at the inlet of the Fischer-Tropsch reaction unit; - a partial or total oxy-combustion reaction unit adapted to at least partially oxidize the gaseous effluent, produce an oxy-combustion effluent comprising carbon dioxide and water, and send the oxy-combustion effluent to the RWGS reaction unit; and - a hydrogen reaction unit (hydrotreating and / or hydrocracking and / or hydroisomerizing unit) suitable for treating hydrocarbon effluent and producing at least one hydrocarbon cut, for example to specifications for transport applications.

[0023] According to one or more embodiments, part of the hydrogen can be supplied downstream of the RWGS reaction unit and upstream of the Fischer-Tropsch reaction unit.

[0024] According to one or more embodiments, the partial or total oxycombustion reaction unit is adapted to produce heat used to supply calories to the RWGS reaction unit and / or the carbon dioxide capture unit (via a feed line), for example by integrating the reaction section of the RWGS reaction unit within the chamber of the partial or total oxycombustion unit.

[0025] According to one or more embodiments, a feed / effluent heat exchange allows the heat available in the RWGS effluent to be used to preheat the gases entering the RWGS reaction unit (gas rich in CO2 and H2).

[0026] According to one or more embodiments, the device comprises a first heat exchanger adapted to generate a second water vapor by exchange thermal between water and RWGS gas which can be used for example to supply thermal energy to the carbon dioxide capture unit.

[0027] According to one or more embodiments, the device includes a first turbine for treating at least part of the gaseous effluent separated by the first separation unit to produce electricity.

[0028] According to one or more embodiments, a second turbine is adapted to treat at least part of the first water vapor and / or the second water vapor to produce electricity.

[0029] According to one or more embodiments, electricity is used to supply calories to the RWGS reaction unit and / or the carbon dioxide capture unit and / or the water electrolysis unit.

[0030] According to one or more embodiments, electricity is used to supply calories to the regeneration section of the carbon dioxide capture unit.

[0031] According to one or more embodiments, the water electrolysis unit treats water from a makeup line and / or RWGS gas and / or FT effluent.

[0032] According to one or more embodiments, the water from the RWGS gas is at least partially or totally separated by a second separation unit to be sent to the water electrolysis unit.

[0033] According to one or more embodiments, the carbon dioxide-rich effluent is purified before being introduced into the RWGS reaction unit. According to one or more embodiments, the RWGS gas is purified before being introduced into the Fischer-Tropsch reaction unit, upstream or downstream of the second separation unit. According to one or more embodiments, the first water effluent is purified before being introduced into the water electrolysis unit. The effluent purification steps aim to remove at least some of the sulfur compounds, nitrogen compounds, halogens, heavy metals, and transition metals. The main gas purification technologies are: adsorption, absorption, and catalytic reactions.

[0034] According to a second aspect, the aforementioned objects, as well as other advantages, are obtained by a carbon dioxide capture and conversion process, comprising the following steps: - treat the load in a carbon dioxide capture unit to produce a carbon dioxide-rich effluent; - convert water in a water electrolysis unit to produce oxygen and hydrogen; - treat the carbon dioxide-rich effluent with hydrogen in a reverse RWGS gas-to-water conversion reaction unit to produce CO and water-enriched RWGS gas; - convert the RWGS gas in a Fischer-Tropsch reaction unit to produce an FT effluent); - optionally generate a first water vapor in the Fischer-Tropsch reaction unit to supply thermal energy to the carbon dioxide capture unit; - treat the FT effluent in a first separation unit to produce at least one hydrocarbon effluent, one first water effluent and one gaseous effluent; - oxidize at least part of the gaseous effluent in a partial or total oxy-combustion reaction unit, to produce an oxy-combustion effluent comprising carbon dioxide and water; - send the oxy-combustion effluent to the RWGS reaction unit; and - treat the hydrocarbon effluent in a hydrogen reaction unit to produce at least one hydrocarbon cut, for example to the specifications required for transport applications.

[0035] According to one or more embodiments, the reaction unit of RWGS comprises at least one reactor used under at least one of the following operating conditions: - temperature between 700°C and 1200°C, preferably between 800°C and 1100°C, and more preferably between 850°C and 1050°C; - pressure between 0.1 MPa and 10 MPa, preferably between 0.1 MPa and 5 MPa, and more preferably between 0.1 MPa and 3.5 MPa; - spatial velocity of the gas at the reactor inlet between 5000 NL / kgcata / h and 40000 NL / kgcata / h; - catalyst comprising 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. According to one or more embodiments, the catalyst for the RWGS reaction comprises a support, for example based on alumina, silica, silica-alumina, alumina-silica.

[0036] According to one or more embodiments, the reaction unit FT comprises at least one reactor used under at least one of the following operating conditions: - temperature between 170°C and 280°C, preferably between 190°C and 260°C and preferably between 210°C and 240°C; - absolute pressure between 1.0 MPa and 6.0 MPa, preferably between 1.5 MPa and 3.5 MPa and preferably between 2.0 MPa and 3.0 MPa; - catalyst comprising cobalt or iron, preferably cobalt, the catalyst optionally comprising a support, for example based on alumina, silica, silica-alumina, alumina-silica or titanium.

[0037] According to one or more embodiments, the partial or total oxycombustion reaction unit comprises at least one reactor used under at least one of the following operating conditions: - absolute pressure between 0.1 MPa and 9 MPa, preferably between 1 MPa and 4 MPa; - temperature between 600°C and 2000°C, preferably between 800°C and 1700°C.

[0038] Embodiments of the device and method according to the aforementioned aspects as well as other characteristics and advantages will become apparent from the following description, given for illustrative purposes only and not as a limitation, and with reference to the following drawing. List of figures

[0039] Fig. 1 shows a schematic representation of a device according to the present invention in which the oxycombustion effluent is notably sent into the reaction unit of RWGS. Description of the implementation methods

[0040] Embodiments of the device according to the first aspect and of the method according to the second aspect will now be described in detail. In the following detailed description, many specific details are presented to provide a more thorough understanding of the device. However, it will be apparent to those skilled in the art that the device can be implemented without these specific details. In other cases, well-known features have not been described in detail to avoid unnecessarily complicating the description.

[0041] In this description, the term "include" is synonymous with (means the same as) "include" and "contain," and is inclusive or open-ended and does not exclude other unstated elements. It is understood that the term "include" includes the exclusive and closed term "consist." Furthermore, in this description, an effluent consisting essentially or solely of compound A corresponds to an effluent consisting of at least 95% by weight, preferably at least 98% by weight, and most preferably at least 99% by weight, of compound A.

[0042] In the present description, the term "physical solvent" is synonymous with (means the same as) a solvent forming weak bonds (e.g. hydrogen bonding, van der Waals bonding) with the solute, a solvent not forming strong bonds (e.g. covalent bonding, ionic bonding) with the solute.

[0043] The present invention can be defined as a device and a method comprising a sequence of unit operations enabling the production of synthetic hydrocarbons, such as synthetic fuels, for example gasoline, kerosene, diesel and / or naphtha or lubricant bases, preferably of very high quality from carbon dioxide from a capture unit.

[0044] The device and method according to the invention are characterized in particular in that they comprise and use carbon dioxide capture units, reverse water gas conversion (RWGS), Fischer-Tropsch synthesis (FT), and treatment units Hydrogen (hydrotreating, and / or hydrocracking, and / or hydroisomerization) of hydrocarbon fractions from the FT reaction unit and partial or total oxy-combustion of gaseous hydrocarbon by-products from the process (RWGS and Fischer-Tropsch synthesis and post-treatment). Advantageously, the necessary hydrogen can be produced by a water electrolysis unit, said water being supplied by the RWGS and Fischer-Tropsch reaction units. Advantageously, the oxygen required for partial or total oxy-combustion can be produced by water electrolysis to supply the partial or total oxy-combustion section, and / or by another unit such as an air separation unit.

[0045] One of the features of the present invention can be summarized as the use of carbon dioxide for the production of synthetic fuels, gasoline, kerosene, diesel fuel, and / or naphtha or very high-quality lubricants. The present invention also relies on the presence of a partial or total oxy-combustion unit that makes it possible to produce a gaseous effluent rich in carbon dioxide by combustion of the gaseous hydrocarbon by-products of the process (RWGS and Fischer-Tropsch synthesis and post-treatment), which allows for improved production of the products of interest.

[0046] Furthermore, the heat released by partial or total oxycombustion can advantageously be used to supply heat to the RWGS reaction unit and / or the carbon dioxide capture unit (2). This heat supply can be achieved by sending the high-temperature oxycombustion effluent (directly) into the RWGS reaction unit, or, for example, by heat exchange with: - the oxy-combustion gas within the partial or total oxy-combustion chamber; and / or - the high-temperature gaseous effluent downstream of the oxy-combustion chamber; and / or - water vapor generated by the partial or total oxycombustion reaction unit and / or by heat exchange with the oxycombustion gaseous effluent.

[0047] According to one or more embodiments, the present invention also makes it possible to minimize the amount of external carbon energy to the process and therefore the impact on the environment, by means of an original energy integration based on the use of the heat at the outlet of the Fischer-Tropsch reaction unit and optionally of the RWGS reaction unit, to desorb carbon dioxide, for example complexed with amine in the carbon dioxide capture unit and more particularly in a solvent regeneration unit.

[0048] According to one or more embodiments, electricity can also be produced by a turbine powered by an effluent from the Fischer-Tropsch reaction unit and / or by steam (e.g., produced at the outlet of the reaction unit). Fischer-Tropsch and / or the reaction unit of RWGS), this electricity allowing, for example, to supply calories to the device according to the invention, for example to the reaction unit of RWGS.

[0049] Thus, the combination of carbon dioxide capture and chemical conversion units with preferably an original thermal integration makes it possible to produce bases for fuels, and in particular for fuel for the aviation sector, while minimizing the environmental impact of the process.

[0050] Preferably, the use of the water electrolysis unit to treat the water produced by the reaction unit of RWGS and / or the Fischer-Tropsch unit also makes it possible to minimize the environmental impact of the process.

[0051] With reference to [Fig. 1], the device for converting carbon dioxide into liquid hydrocarbons comprises: - a carbon dioxide capture unit 2 adapted to treat a feed 1 containing carbon dioxide and produce an effluent (gaseous) rich in carbon dioxide 3 (i.e., enriched in carbon dioxide compared to the feed 1); - a water electrolysis unit 5 adapted to treat water 4 (fresh or recycled) to produce oxygen 6 and hydrogen 7; - a reaction unit of RWGS 8 adapted to convert at least partially the carbon dioxide from the carbon dioxide-rich effluent 3 into a CO-rich RWGS 9 gas (i.e., synthesis gas enriched in CO (and water) relative to the carbon dioxide-rich effluent 3); - a Fischer-Tropsch (FT) reaction unit 13 adapted to convert RWGS gas 9 and produce a Fischer-Tropsch (FT) effluent 14, and optionally adapted to generate a first water vapor 22, generated for example by the vaporization of water in an exchanger located inside the reaction unit FT 13, to supply thermal energy to the carbon dioxide capture unit 2; - a first separation unit 15 adapted to treat at least part of the effluent FT 14 and produce: at least one hydrocarbon effluent 17, a gaseous effluent 18 (off-gas), and a first water effluent 16 product of the Fischer-Tropsch synthesis resulting from the condensation of gaseous water under the operating conditions of the Fischer-Tropsch reaction; - a partial or total oxy-combustion reaction unit 28 adapted to oxidize at least a part 24 of the gaseous effluent 18 separated by the first separation unit 15, produce an oxy-combustion effluent 29 comprising carbon dioxide and water, and send the oxy-combustion effluent 29 to the RWGS reaction unit 8; - a hydrogen reaction unit 20 (hydrotreating and / or hydrocracking and / or hydroisomerization unit) adapted to treat the effluent hy drocarbon 17 with hydrogen 7 and separate at least one hydrocarbon cut 21 comprising for example at least one of the following cuts: naphtha, gasoline, kerosene, diesel, and lubricant base; - optionally at least one heat exchanger 31 adapted to generate a second water vapor 23 by heat exchange between water and RWGS gas 9, which can be used, for example, to supply thermal energy to the carbon dioxide capture unit 2; and - preferably a separation unit 10 adapted to treat the RWGS gas 9 to produce a water-depleted RWGS gas 12 (relative to the RWGS gas 9), sent to the FT reaction unit 13 instead of the RWGS gas 9, and send a second water effluent 11 to the water electrolysis unit 5.

[0052] Advantageously, the reaction unit FT 13 and optionally the first heat exchanger 31 are adapted to produce steam by heat exchange. Advantageously, the use of steam makes it possible to supply energy to the carbon dioxide capture unit 2, for example by regenerating an amine-based solvent (or a physical solvent) loaded with carbon dioxide in a regeneration unit of the carbon dioxide capture unit 2, or by supplying alternating temperature adsorption equipment.

[0053] To avoid unnecessarily complicating the description and figures, it will be apparent to those skilled in the art that the water supplies to the reaction unit of FT 13 and to the heat exchanger 31 for generating steam have not been described in detail. The same applies to the water outlet of the carbon dioxide capture unit 2. Carbon dioxide capture unit

[0054] The carbon dioxide capture unit 2 separates the carbon dioxide from the rest of the feed 1. Such a carbon dioxide capture unit typically provides CO2 that can be compressed for use or storage. According to one or more embodiments, the feed 1 comprises at least 0.04% vol. of carbon dioxide, preferably at least 2% vol. of carbon dioxide, and most preferably at least 10% vol. of carbon dioxide.

[0055] According to one or more embodiments, charge 1 comprises or consists of combustion fumes. According to one or more embodiments, charge 1 comprises gaseous effluents from at least one unit selected from the group consisting of: a refinery, an incinerator, a petrochemical unit, a chemical unit, a thermal power plant, a paper mill, an ethanol plant, a sugar refinery. According to one or more embodiments, charge 1 comprises gaseous effluents from a cement plant, and / or gaseous effluents from a lime production unit, and / or gaseous effluents from blast furnaces. According to one or more In these embodiments, the combustion fumes originate from a combustion chamber (e.g., a boiler) adapted to burn a fuel, such as coal, natural gas, fuel oil, biogas, biomass, organic waste, urban waste, with an oxidant, generally air.

[0056] According to one or more embodiments, the charge 1 comprises or consists of biogas, natural gas, synthesis gas, refinery gas, biomass fermentation gas, cement plant gas and / or blast furnace gas.

[0057] Carbon dioxide can also be carbon dioxide present in the air. According to one or more embodiments, the charge 1 comprises or consists of air. For example, the carbon dioxide capture unit 2 may include a direct air capture device (or "DAC").

[0058] For capture, several agents can be used, such as solvents and solids. According to the invention, the carbon dioxide capture unit 2 employs at least one amine-based solvent, and / or at least one physical solvent such as, for example, one based on polyethylene glycol dimethyl ether), and / or alternating temperature adsorption (physical adsorption) equipment.

[0059] A widely used carbon dioxide capture technology relies on the phenomenon of absorption, namely the transfer of a chemical species from a gas to a liquid. The gas containing the impurities, or the species to be separated, is sent into a column where it is brought into contact with a liquid solvent. The two flows can be implemented in various hydrodynamic configurations (co-current, cross-current, or counter-current, the latter being preferred for reasons of favorable thermodynamic equilibrium). This absorption is achieved using an absorbing solution, comprising a chemical solvent or a physical solvent, this distinction being related to whether or not a chemical reaction occurs between the absorbed component and the solvent.

[0060] Physical absorption is preferred in order to minimize the energy cost of the process; this is particularly suitable in the case of high partial pressure of the species to be separated.

[0061] Chemical absorption is preferred in cases of high dilution and low partial pressure of the species to be separated and / or when a high recovery rate of this species is desired, or finally, if a stringent specification regarding the maximum permissible concentration of this species in the gas stream after scrubbing is required. Thus, for carbon dioxide capture from (industrial) flue gases with low carbon dioxide concentrations, typically between 3 and 15% by volume (typically in low-pressure gases), scrubbing by chemical absorption, for example using an amine solvent, by An example of the alkanolamine type is well suited.

[0062] Absorbent solutions commonly used today are aqueous solutions comprising one or more reactive compounds or compounds exhibiting a physicochemical affinity for acidic compounds. The reactive compounds may be, for example, but not limited to, amines (primary, secondary, tertiary, cyclic or non-cyclic, aromatic or non-aromatic, saturated or unsaturated), alkanolamines, polyamines, amino acids, alkali salts of amino acids, amides, ureas, phosphates, carbonates, or alkali metal borates. According to one or more embodiments, the absorbent solution is an aqueous solution comprising one or more reactive compounds with an amine functional group and whose structure is described from page 6, line 1 to page 7, line 3, of patent application WO2007 / 104856.

[0063] According to one or more embodiments, the reactive compounds represent from 10% by weight to 90% by weight, preferably between 20% by weight and 50% by weight, most preferably between 25% by weight and 40% by weight, of the total weight of the absorbing solution.

[0064] Chemical absorption with amine solvents is based on acid-base equilibria, with low temperatures favoring the reaction between the basic amine and the acidic carbon dioxide, and high temperatures favoring the reverse reaction. Thus, amine processes, using for example an aqueous phase with 20-50% by mass of amine(s), can employ two columns (not shown) in which the solvent flows from one to the other. In the first column, called the absorber, the stream to be washed (i.e., the load 1) is brought into contact with the amine solvent at low temperature. The amine solvent flows through the column and captures the carbon dioxide.At the bottom of the column, the amine solvent (the "rich" solvent) reaches a predetermined loading rate, the ratio between the number of moles of carbon dioxide captured and the number of moles of amines. At the top of the column, the gaseous stream exits at predetermined specifications, namely a carbon dioxide content, for example, nearly 10 times lower than the initial concentration in the flue gases. The rich solvent is sent to the second column, called the regenerator, which operates similarly to a distillation column, running at high temperature. The regenerated amine solvent (the "lean" solvent) can then be returned to the absorber. The amine solvent thus circulates continuously in a closed loop from one column to the other, preferably passing through a feed / effluent heat exchanger that cools the lean solvent and preheats the rich solvent, thereby saving energy at the process scale.

[0065] According to one or more embodiments, the regenerator operates at a high temperature between 90°C and 250°C, preferably between 110°C and 240°C, very preferably between 120°C and 200°C at the bottom of the column.

[0066] The carbon dioxide released from the regenerator can then optionally be compressed and recovered. According to one or more embodiments, the carbon dioxide-rich effluent 3 comprises at least 90% vol. of carbon dioxide, preferably at least 95% vol. of carbon dioxide, most preferably at least 98% vol. of carbon dioxide. According to one or more embodiments, the carbon dioxide-rich effluent 3 has a temperature between 20°C and 250°C, preferably between 30°C and 200°C, most preferably between 40°C and 150°C, at the outlet of the carbon dioxide capture unit 2. According to one or more embodiments, the carbon dioxide-rich effluent 3 has a pressure between 0.20 MPa and 4 MPa, preferably between 0.30 MPa and 3.5 MPa, most preferably between 0.4 MPa and 3 MPa, at the outlet of the carbon dioxide capture unit 2.

[0067] A key aspect of industrial flue gas treatment operations using solvents is the regeneration step of the separating agent. Depending on the type of absorption (physical and / or chemical), regeneration is generally considered to be carried out by expansion, and / or by distillation, and / or by entrainment with a vaporized gas called a "stripping gas."

[0068] One of the main limitations of solvents commonly used today is the need for high flow rates of absorbing solution, which results in significant energy consumption for solvent regeneration, as well as large equipment sizes (columns, pumps, etc.). This is particularly true when the partial pressure of carbon dioxide is low. Such energy consumption represents a considerable operating cost for the carbon dioxide capture process. The regeneration energy depends on the nature of the amines and the partial pressure of carbon dioxide and is typically between 2 GJ / t and 4 GJ / t of carbon dioxide captured. Newer capture processes tend to reduce this energy to values ​​below 2 GJ / t of carbon dioxide.In the context of air treatment, since carbon dioxide concentrations are very low, the energy consumed is very high, on the order of 5 GJ / t of carbon dioxide to 7.5 GJ / t of carbon dioxide.

[0069] Another possible implementation is based on the principle of adsorption using a solid adsorbent with a strong chemical affinity for carbon dioxide. To ensure continuous operation, the processes operate with several reactors in parallel. Carbon dioxide is adsorbed onto the solid adsorbent, and the stream to be treated (i.e., the load 1) becomes depleted as it passes through the solid bed, and at the outlet, the stream contains little or no 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 The reactor containing a solid adsorbent unsaturated with carbon dioxide is operating, and the carbon capture process continues. In parallel, the carbon dioxide-saturated reactors are undergoing a regeneration process. - through a temperature increase, this is referred to as temperature swing adsorption (or "TSA" for "Temperature Swing Adsorption" according to Anglo-Saxon terminology); and - by partial vacuuming, we then speak of pressure inversion adsorption (or "VPSA" for "Vacuum Pressure Swing Adsorption" according to Anglo-Saxon terminology, or simply "VSA" or "PSA", possibly in the presence of a gas promoting desorption).

[0070] The main drawback of TSA processes is the large amount of heat required for regeneration. The thermal integration proposed in the present invention overcomes this drawback.

[0071] According to one or more embodiments, the solid adsorbent for carbon dioxide capture is selected from the following compounds: activated carbon, zeolites, aluminas, silicas, synthetic fibers with or without impregnated amines, metal-organic framework (MOF) solids, and supported alkali carbonates. These solid adsorbents are increasingly used for capturing carbon dioxide from the air. The regeneration energy of physisorption adsorbents in these cases, for example on zeolites, is on the order of 0.6 to 0.9 GJ / t of carbon dioxide. For amines supported on solids, the regeneration energy is between 5.4 and 7.2 GJ / t of carbon dioxide.

[0072] Advantageously, the energy required for the regeneration of the amine solvent and / or the temperature rise of the solid adsorbent can be supplied at least partially by the first water vapor 22 and optionally by the second water vapor 23. This energy input to the carbon dioxide capture unit 2 makes it possible to maximize the energy efficiency of the process.

[0073] According to one or more embodiments, the temperature of the water vapor 22 and / or 23 is at least 110°C, preferably at least 120°C, most preferably at least 130°C, for example at the outlet of the heat exchanger 31 and / or the reaction unit FT 13. According to one or more embodiments, the temperature of the water vapor 22 and / or 23 is between 110°C and 270°C, preferably between 120°C and 260°C, most preferably between 130°C and 220°C, for example at the outlet of the heat exchanger 31 and / or the reaction unit FT 13. According to one or more embodiments, the water vapor 22 and / or 23 has a pressure between 0.1 MPa and 4 MPa, preferably between 0.1 MPa and 3.5 MPa, preferably between 0.1 MPa and 1.7 MPa, for example at the outlet of the heat exchanger 31 and / or of the reaction unit FT 13. Water electrolysis unit

[0074] The water electrolysis unit 5 processes water 4 from: a booster line and / or the second optional separation unit 10 and / or the first separation unit 15.

[0075] According to one or more embodiments, the water electrolysis unit 5 includes a pre-treatment section adapted to extract oxygenated compounds from water 4, for example from the first water effluent 16.

[0076] According to one or more embodiments, the water electrolysis unit 5 comprises at least one alkaline electrolyzer. Other electrolysis technologies may 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 diaphragm / membrane) are then specific to each technology.

[0077] According to one or more embodiments, the water electrolysis unit 5 comprises at least one reactor used under at least one of the following operating conditions: Alkaline-type electrolyzer: - temperature between 60°C and 90°C, - pressure between 0.1 MPa and 20 MPa, preferably between 0.1 MPa and 4 MPa, - electrolyte containing KOH, - electrodes comprising a metallic alloy, - diaphragm comprising asbestos, polytetrafluoroethylene and / or nickel oxide; Proton exchange membrane (PEM) electrolyzer: - temperature between 50°C and 80°C, - pressure between 0.1 MPa and 20 MPa, preferably between 1.8 MPa and 5.5 MPa, - Electrolyte comprising a polymer membrane, - Electrodes comprising a metallic alloy; Solid oxide electrolyzer (SOE): - temperature between 800°C and 900°C, - pressure between 0.1 MPa and 2 MPa, preferably between 0.1 MPa and 0.5 MPa, - electrolyte including a ceramic membrane (e.g. perovskite type), - electrodes including a metallic alloy; Anion exchange membrane (AEM) type electrolyzer: - temperature between 50°C and 70°C, - pressure between 0.1 MPa and 20 MPa, preferably between 0.1 MPa and 3.5 MPa, - electrolyte comprising a polymer membrane, - electrodes comprising a metallic alloy.

[0078] According to one or more embodiments, the oxygen 6 produced by the water electrolysis unit 5 comprises between 99.0% by weight and 99.8% by weight of O2 (after drying).

[0079] According to one or more embodiments, the hydrogen 7 produced by the water electrolysis unit 5 comprises between 99.5% by weight and 99.999% by weight of H2 (after drying).

[0080] Advantageously, oxygen 6 is used for partial or total oxycombustion. 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 oxycombustion is carried out at a pressure higher than the pressure at which the oxygen 6 is produced in the water electrolysis unit 5.

[0081] Thus, the invention makes it possible to generate heat by utilizing the oxygen 6 produced by the water electrolysis unit 5 within the oxycombustion unit, the resulting oxycombustion effluent 29 being able to be directly introduced into the RWGS reaction unit 8. In this way, part of the energy used for electrolysis is reintroduced into the system as heat via the oxygen 6 as an energy carrier. This represents an advantage over the conventional oxycombustion operation, which requires producing pure oxygen by separating oxygen from the air, an energy-intensive step.

[0082] According to one or more embodiments, the water electrolysis unit 5 is based on a solid oxide electrolyzer (SOE) technology in which at least part of the water 4 can be in the form of vapor supplied at least partially by the first water vapor 22 and optionally the second water vapor 23. This energy input to the electrolysis unit 5 makes it possible to improve the energy efficiency of the process. RWGS reaction unit

[0083] The RWGS reaction unit 8 produces an RWGS gas 9 (synthesis gas) enriched in CO (and depleted in hydrogen) relative to the carbon dioxide-rich effluent 3, which contains unconverted carbon dioxide and water. The hydrogen 7 required for the RWGS reaction comes from the water electrolysis unit 5.

[0084] According to one or more embodiments, the reaction unit of RWGS 8 comprises at least one reactor used under at least one of the following operating conditions: - temperature between 700°C and 1200°C, preferably between 800°C and 1100°C, and even more preferably between 850°C and 1050°C; - pressure between 0.1 MPa and 10 MPa, preferably between 0.1 MPa and 5 MPa, and more preferably between 0.1 MPa and 3.5 MPa; - spatial velocity of the gas at the reactor inlet between 5000 NL / kgcata / h and 40000 NL / kgcata / h; - catalyst based on the elements Ni, Cu, Fe, Co or precious metals such as Pt, Pd, Ru, Ag and Au. According to one or more embodiments, the catalyst for the RWGS reaction comprises a support, for example based on alumina, silica, silica-alumina, alumina-silica.

[0085] According to one or more embodiments, the quantity of hydrogen at the inlet of the reaction unit of RWGS 8 is adjusted so that the H2 / CO molar ratio at the outlet of the reaction unit of RWGS 8 is compatible with the need of the FT unit, i.e. between 0.5 and 4, preferably between 1 and 3, more preferably between 1.5 and 2.5.

[0086] According to one or more embodiments, the RWGS 9 gas has an outlet temperature of the RWGS 8 reaction unit of at least 700°C, preferably at least 750°C, very preferably at least 800°C.

[0087] According to one or more embodiments, at least a portion of the RWGS 9 gas supplies energy to the regeneration unit of the carbon dioxide capture unit 2, by means of the first heat exchanger 31 producing the second water vapor 23 by (indirect) heat exchange between water (not shown) and the RWGS 9 gas, preferably directly at the outlet of the RWGS 8 reaction unit.

[0088] The gas from RWGS 9 is preferably sent to the second separation unit 10. Fischer-Tropsch reaction unit

[0089] According to the invention, in the reaction unit FT 13, carbon monoxide and hydrogen present in the RWGS 9 gas (preferably depleted in water) react to produce a stream comprising an effluent FT 14 comprising unconverted synthesis gas, CO2, gaseous and liquid hydrocarbon products and water.

[0090] According to one or more embodiments, the RWGS 9 gas (preferably depleted in water) sent to the reaction unit FT 13 comprises carbon monoxide and hydrogen with an H2 / CO molar ratio of between 0.5 and 4, preferably between 1 and 3, more preferably between 1.5 and 2.5. According to one or more embodiments, the quantity of hydrogen upstream (e.g. at the inlet) of the reaction unit FT 13 is adjusted, for example by means of an optional hydrogen supply, so that the H2 / CO molar ratio is as defined above.

[0091] The FT 13 reaction unit is implemented in a reaction unit comprising one or more suitable reactors, the technology of which is known from the skilled person. It may be, for example, one or more multitubular fixed bed reactors, or one or more bubble column type reactors ("slurry bubble column" according to Anglo-Saxon terminology), or one or more microchannel reactors.

[0092] According to one or more embodiments, the reaction unit FT 13 employs one or more bubble column reactors. Since the synthesis is highly exothermic, this embodiment allows, among other things, for improved thermal control of the reactor and minimal pressure drop.

[0093] The catalyst used in this Fischer-Tropsch synthesis is generally any catalytic solid known to those skilled in the art that can carry out the 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, for example, based on alumina, silica, silica-alumina, alumina-silica, or titanium.

[0094] According to one or more embodiments, the reaction unit FT 13 comprises at least one reactor used under at least one of the following operating conditions: - temperature between 170°C and 280°C, preferably between 190°C and 260°C and preferably between 210°C and 240°C, - absolute pressure between 1.0 MPa and 6.0 MPa, preferably between 1.5 MPa and 3.5 MPa and preferably between 2.0 MPa and 3.0 MPa.

[0095] The effluent FT 14 is sent to the first separation unit 15. According to one or more embodiments, the effluent FT 14 has an outlet temperature of the reaction unit FT 13 of at least 170°C, preferably of at least 190°C, very preferably of at least 210°C.

[0096] According to one or more embodiments, the reaction unit FT 13 is adapted to produce the first water vapor 22 and supply thermal energy to the carbon dioxide capture unit 2. The first water vapor 22 is generated for example by the vaporization of water (not shown) in a heat exchanger located inside the reaction unit FT 13 allowing the heat from the Fischer-Tropsch reaction, an exothermic reaction, to be removed. First separation unit

[0097] In the first separation unit 15, at least a (first) part of the effluent FT 14 is treated to produce: - hydrocarbon effluent 17 (depleted in water compared to effluent FT 14), - the gaseous effluent 18, and - the first water effluent 16.

[0098] According to one or more embodiments, a second part of the effluent FT 14 is sent directly to the hydrogen reaction unit 20. Preferably, said second part of the effluent FT 14 is a liquid fraction, preferably containing little or no water.

[0099] At the outlet of the first separation unit 15, the hydrocarbon effluent 17 is sent to the hydrogen reaction unit 20, and the first water effluent 16 is optionally sent to the water electrolysis unit 5 by means of a first recycle line.

[0100] According to one or more embodiments, the hydrocarbon effluent 17 comprises: n-paraffins, olefins and oxygenated compounds resulting from the condensation of gaseous hydrocarbons under the operating conditions of the Fischer-Tropsch reaction.

[0101] According to one or more embodiments, the gaseous effluent 18 comprises unconverted synthesis gas, carbon dioxide and gaseous hydrocarbons such as paraffins from Cl to C4 (mostly), olefins from C2 to C4, and oxygenated compounds from Cl to C3.

[0102] According to one or more embodiments, the first water effluent 16 is produced from the Fischer-Tropsch synthesis from the condensation of gaseous water under the operating conditions of the Fischer-Tropsch reaction.

[0103] According to one or more embodiments, the hydrocarbon effluent 17 comprises less than 5% by weight of water, preferably less than 2% by weight of water, very preferably less than 1% by weight of water.

[0104] According to one or more embodiments, a (first) part 19 of the gaseous effluent 18 is sent to the reaction unit FT 13 by means of a second recycle line.

[0105] According to one or more embodiments, at least one (second) part 24 of the gaseous effluent 18 is treated by the first turbine 26 to produce electricity, the gas 27 exiting the first turbine 26 is sent to the oxy-combustion reaction unit 28.

[0106] According to one or more embodiments, a (third) part of the gaseous effluent 18 is recycled in the reaction unit of RWGS 8 (not shown) in order to be converted into synthesis gas and thus improve the mass yield of the process chain.

[0107] According to one or more embodiments, a (fourth) part of the gaseous effluent 18 is sent to an independent synthesis gas production unit (not shown), for example of the type: - partial oxidation (or "POx" for "Partial oxidation" according to Anglo-Saxon terminology); - Steam methane reforming (or "SMR" for "Steam Methane") Reforming (according to Anglo-Saxon terminology); - autothermal reforming (or "ATR" for "Autothermal Reforming" according to Anglo-Saxon terminology); - Enhanced Heat Transfer Reformer (or "EHTR" for "Enhanced Heat Transfer Reformer" according to Anglo-Saxon terminology). According to one or more embodiments, said synthesis gas produced in the independent unit is recycled at the inlet or outlet of the reaction unit of RWGS 8.

[0108] Partial or total oxycombustion reaction unit

[0109] According to the invention, at least a portion 24 of the gaseous effluent 18 is sent into the partial or total oxy-combustion reaction unit 28, in which the hydrocarbon compounds, carbon monoxide and hydrogen present (i.e., CO, H2, paraffins and olefins of 1 to 7 carbon atoms per molecule, and alcohol compounds of 1 to 3 carbon atoms per molecule) are converted at least partially into carbon dioxide and water in the presence of oxygen 6, to produce an oxy-combustion gas comprising (essentially) carbon dioxide and water (and optionally CO and H2 if partial oxy-combustion).

[0110] Total oxy-combustion is a common process 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 pure oxygen. Pure oxygen (O2) (i.e., at least 95% by weight, preferably at least 98% by weight, most 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. A flue gas, called oxy-combustion effluent 29, with a high concentration of carbon dioxide and water vapor (compared to the gaseous effluent 18), is then produced at the oxy-combustion outlet. In the context of the present invention, the oxycombustion effluent 29 at the outlet of the oxycombustion reaction unit 28 is introduced into the RWGS reaction unit 8, so as to convert the carbon dioxide.Oxycombustion technologies are well known to those skilled in the art; for example, see: Int. J. Energy Res., 2017, 41, p. 1670-1708; Energies 2021, 14, p. 4333 and WO 2006 / 013290.

[0111] Partial oxycombustion (POX), sometimes called gasification technology, is a slightly exothermic process that can be used as an alternative to steam reforming of methane to produce syngas or hydrogen. This reaction can be applied to hydrocarbons (light, heavy, asphalt, petroleum coke) but also to coal and biomass (e.g., wood, green waste, etc.). Partial oxycombustion is preferably carried out at high temperature (e.g., between 1100°C and 1500°C) and pressure (e.g., between 1 MPa and 9 MPa or more), in the presence of pure oxygen and without a catalyst. The reaction corresponds to partial oxidation Properly speaking, it is a reaction that raises the gaseous mixture to a temperature ranging, for example, from 1000°C to 1400°C, after preheating, for example, to 300°C. The industrial process of partial oxy-combustion is well known to those skilled in the art, a process commercialized by Shell, Texaco, BASF-Lurgi, Air Liquide, etc. See, for example, chapters Hydrogen, 2. Production (p. 249 vol. 18) and Carbon Monoxide (p. 679 vol. 6) of Ullmann's Encyclopedia of Industrial Chemistry.

[0112] In the case of a complete oxy-combustion operation, it will preferably be carried out at oxygen stoichiometry so as to obtain the complete (or total) oxidation of the hydrocarbon, hydrogen, and carbon monoxide mixture, so that the oxy-combustion effluent 29 after cooling contains essentially carbon dioxide, water, and oxygen (preferably at an oxygen concentration of less than 0.3% by volume). When the oxy-combustion is partial, it is preferably carried out at sub-oxygen stoichiometry to produce a mixture of carbon dioxide, carbon monoxide, and hydrogen (CO2, CO, and H2).

[0113] 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, namely water vapor, or carbon dioxide, alone or in a mixture, for example by recycling the oxycombustion products if necessary.

[0114] According to one or more embodiments, in order to obtain an oxy-combustion temperature within the desired range, a portion of the carbon dioxide-rich effluent 3 is introduced into the total or partial oxy-combustion unit 28. This introduction can take place directly into the total or partial oxy-combustion unit 28 or after prior mixing with at least a second portion 24 of the gaseous effluent 18 or after mixing with oxygen 6. For example, in the case of partial oxy-combustion, the oxygen flow rate can be adjusted to obtain the desired temperature in the oxy-combustion chamber and to minimize the light hydrocarbon content in the oxy-combustion effluent 29.

[0115] According to one or more embodiments, the partial or total oxycombustion reaction unit 28 comprises at least one reactor used under at least one of the following operating conditions: - absolute pressure between 0.1 MPa and 9 MPa, and preferably between 1 MPa and 4 MPa; - temperature between 600°C and 2000°C, preferably between 800°C and 1700°C, preferably between 1100°C and 1500°C.

[0116] According to one or more embodiments, the total oxy-combustion reaction unit 28 comprises at least one reactor used under at least one of the following operating conditions: - absolute pressure between 0.1 MPa and 4 MPa; - temperature between 600°C and 2000°C, preferably between 800°C and 1700°C, preferably between 800°C and 1500°C; - presence of oxygen used for combustion, preferably at stoichiometry, for complete oxidation of all fuels (e.g. hydrocarbons, CO and H2), preferably so as to have an oxygen concentration of less than 0.3% by volume, and / or a total fuel concentration of less than 1% by volume in the oxycombustion effluent 29.

[0117] According to one or more embodiments, the partial oxy-combustion reaction unit 28 comprises at least one reactor used under at least one of the following operating conditions: - absolute pressure between 0.1 MPa and 9 MPa or more; - temperature between 600°C and 2000°C, preferably between 800°C and 1700°C, preferably between 1100°C and 1500°C. - The presence of oxygen used for combustion, preferably with an oxygenation ratio between 0.3 and 0.8, but very preferably between 0.4 and 0.7, to promote the formation of carbon monoxide. The oxygenation ratio is defined as the ratio of the injected molar flow rate to the theoretical oxygen flow rate required for complete oxidation of all hydrocarbons.

[0118] According to one or more embodiments, a so-called "light" hydrocarbon fraction (not shown) from the hydrogen reaction unit 20 is sent at least partially to the partial or total oxy-combustion reaction unit 28 (not shown). According to one or more embodiments, the hydrocarbon fraction comprises gaseous hydrocarbons such as paraffins from Cl to C4.

[0119] According to one or more embodiments, the oxycombustion gas produced in the partial or total oxycombustion reaction unit 28 has a temperature between 600°C and 2000°C and preferably between 800°C and 1700°C and preferably between 900°C and 1500°C, and an absolute pressure between 0.1 MPa and 9 MPa, preferably between 1 MPa and 4 MPa.

[0120] The oxycombustion gas produced in the partial or total oxycombustion reaction unit 28 being at high temperature allows, via the feed line 32, to supply part of the necessary calories to the RWGS reaction unit 8 and / or the carbon dioxide capture unit 2.

[0121] The supply of calories can be achieved, for example, by heat exchange with water vapor produced by the oxy-combustion reaction unit 28 and / or heat exchange within the combustion chamber of the oxy-combustion reaction unit 28 and / or heat exchange with the high-temperature oxy-combustion gaseous effluent 29 downstream of the reaction unit oxycombustion 28. For example, after the transfer of calories from the oxycombustion gas in the oxycombustion chamber for example to the RWGS reaction 8, the residual heat contained in the oxycombustion effluent 29 at the outlet of the oxycombustion reaction unit 28 can be used to produce steam, sent for example to the carbon dioxide capture unit 2.

[0122] Advantageously, the supply of calories can be done simply by sending the high-temperature oxy-combustion effluent 29 (directly) into the reaction unit of RWGS 8.

[0123] Advantageously, the partial or total oxycombustion reaction unit 28 makes it possible to convert substantially all the hydrocarbon by-products of the process into carbon dioxide, and optionally into CO and H2, and thus to valorize them in the form of the desired products. The yield of desired products from the process according to the invention is thus improved.

[0124] The oxycombustion effluent 29 exiting the partial or total oxycombustion reaction unit 28 is recycled to the inlet of the RWGS reaction unit 8. Hydrogen reaction unit

[0125] The hydrocarbon effluent 17 is sent to the hydrogen reaction unit 20 to undergo a hydrotreating and / or hydrocracking and / or hydroisomerization reaction, in which one or more hydrocarbon fractions 21 can be recovered, in particular synthetic fuels, namely gasoline, kerosene, diesel fuel, and / or other hydrocarbon products, such as naphtha, or very high-quality lubricant bases (essentially free of sulfur, aromatics, and nitrogen). One possible option is the production of paraffinic fractions, basic products for petrochemical processes, for example, the production of a C10-C13 fraction for the production of linear alkylbenzene (or "LAB" for "Linear Alkyl Benzene" according to Anglo-Saxon terminology), or waxes for various industrial applications.

[0126] According to one or more embodiments, the hydrogen reaction unit 20 comprises at least one reactor used under at least one of the following operating conditions: - temperature between 250°C and 450°C, more preferably between 280°C and 450°C, and even more preferably between 320°C and 420°C; - pressure between 0.2 MPa and 15 MPa, preferably between 0.5 MPa and 12 MPa, more preferably between 1 MPa and 10 MPa; - spatial velocity defined as the ratio of the volumetric flow rate of the charge at ambient temperature and pressure to the volume of the catalyst, between 0.1 h 1 and 10 h1, preferably between 0.2 h ' and 7 h1, more preferably between 0.5 h 1 and 5 h 1; - hydrogen flow rate between 100 and 2000 normal liters of hydrogen per liter of charge per hour and preferably between 150 and 1500 normal liters of hydrogen per liter of charge and more preferably between 300 and 1500 normal liters of hydrogen per liter of charge.

[0127] According to one or more embodiments, the hydrotreating and / or hydrocracking and / or hydroisomerization catalyst comprises at least one hydrogenating-dehydrogenating metal selected from the group comprising the metals of group VIB and group VIIIB of the periodic table and at least one solid which is a Brønsted acid, i.e. a solid 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 noble metal from group VIIIB selected from ruthenium, rhodium, palladium, osmium, iridium and platinum, taken alone or in mixture, and preferably from platinum and palladium taken alone or in mixture, 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; at least one support selected from aluminas, boron oxides, magnesia, zirconia, titanium oxides, and clays. According to one or more embodiments, the support is alumina, silica-alumina, alumina-silica, or silica.

[0130] According to one or more embodiments, the hydrotreating and / or hydrocracking and / or hydroisomerization catalyst comprises at least one base metal from group VIIIB selected from nickel and cobalt in combination with at least one metal from group VIB selected from molybdenum and tungsten, used alone or in mixture, and preferably used in their sulfide form.

[0131] According to one or more embodiments, in the case where said hydrotreating and / or hydrocracking and / or hydroisomerizing catalyst comprises at least one noble metal from group VIIIB, the noble metal content of said catalyst is between 0.01% and 5% by weight, preferably between 0.05% and 4% by weight and very preferably between 0.10% and 2% by weight, relative to the total weight of the catalyst.

[0132] According to one or more embodiments, where said hydrotreating and / or hydrocracking and / or hydroisomerization catalyst comprises at least one metal from Group VIB in combination with at least one non-noble metal from Group VIII selected from nickel and cobalt, the content of the Group VIB metal in said catalyst is between 5% and 40% by weight, preferably between 10% and 35% by weight, and the content of the Group VIIIB metal in said catalyst is between 0.5% and 15% by weight, preferably between 1% and 10% by weight, preferably between 1% and 8% by weight, and very preferably between 1.5% and 6% by weight, relative to the total weight of the catalyst.

[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 and 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, that is to say, it has a hydro-dehydrogenating function and a hydro-isomerizing function. Second separation unit

[0135] In the second separation unit 10, the RWGS gas 9 is treated, for example by condensation, to produce the water-depleted RWGS gas 12 (relative to the RWGS gas 9) and recycle, for example, the second water effluent 11 to the water electrolysis unit 5.

[0136] According to one or more embodiments, the water-depleted RWGS gas 12 comprises less than 1 mole percent of water, preferably less than 0.5 mole percent of water, very preferably less than 0.25 mole percent of water.

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

[0138] With reference to [Fig.1], according to one or more embodiments, the present invention makes it possible to recover energy in the form of electricity by means of at least one turbine 26.

[0139] According to one or more embodiments, the first turbine 26 is adapted to treat at least a part 24 of the gaseous effluent 18 to produce electricity.

[0140] According to one or more embodiments, a second turbine (not shown) is adapted to treat at least part of the first water vapor 22 and / or the second water vapor 23 to produce electricity (not shown).

[0141] According to one or more embodiments, electricity is used to supply heat 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 supply heat 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 charge of the RWGS reaction unit 8. Carbon dioxide separation unit

[0142] According to one or more embodiments, the device further comprises a unit of separation of carbon dioxide and optionally methane (not shown), compounds potentially present in the gas of RWGS 9. Advantageously, the carbon dioxide can be recycled in the reaction unit of RWGS 8.

[0143] According to one or more embodiments, the carbon dioxide separation unit is arranged between the reaction unit of RWGS 8 and the reaction unit FT 13. Advantageously, the size of the reaction unit FT 13 can thus be reduced.

[0144] According to one or more embodiments, the carbon dioxide separation unit is arranged at the outlet of the reaction unit FT 13. Wastewater treatment units

[0145] According to one or more embodiments, the carbon dioxide-rich effluent 3 is purified before being introduced into the RWGS reaction unit 8. According to one or more embodiments, the RWGS gas 9 is purified before being introduced into the FT reaction unit 13, upstream or downstream of the second separation unit 10. According to one or more embodiments, the first water effluent 16 is purified before being introduced into the water electrolysis unit 5. The effluent purification steps aim to remove at least some of the sulfur compounds, nitrogen compounds, halogens, heavy metals, and transition metals. The main gas purification technologies are: adsorption, absorption, and catalytic reactions.

[0146] In this description, chemical element groups are given by default according to the CAS classification (CRC Handbook of Chemistry and Physics, publisher CRC Press, editor-in-chief DR Lide, 81st edition, 2000-2001). For example, group VIIIB according to the CAS classification corresponds to the metals in columns 8, 9, and 10 according to the new IUPAC AC classification; group VIB according to the CAS classification corresponds to the metals in column 6 according to the new IUPAC classification. Examples

[0147] The various examples relate to sequences, conforming or not conforming to the invention, the objective of which is to produce a hydrocarbon fraction from flue gases containing 21 wt% of CO2. The flow rate of flue gases to be treated is 3641 kg / h for all the examples.

[0148] Example 1 not in accordance with the invention

[0149] Example 1 illustrates the operation of the sequence of the CO2 capture unit 2 followed by the RWGS reaction unit 8, then the FT reaction unit 13, and the hydrogen reaction unit 20, with combustion of the portion 24 of the gaseous effluent 18 in air in a burner. Burning the gases in air does not allow the combustion fumes to be sent directly to the RWGS reaction unit 8 and necessitates the removal of NOx and the separation of CO2 from nitrogen and oxygen in the CO2 capture unit 2.

[0150] The total flue gas flow rate feeding the CO2 capture unit 2 is 5509 kg / h, corresponding to the flue gas flow rate to be treated of 3641 kg / h to which must be added the flow rate of 1868 kg / h of flue gas from combustion.

[0151] 1331 kg / h of water 4 supplies the water electrolysis unit 5, of which 672 kg / h is water fresh. The electrical consumption of the water electrolysis unit 5 is 5.8 MWe.

[0152] The quantity of first water vapor 22 generated by the reaction unit FT 13 is 1310 kg / h. The heat exchanger 31 generates 1295 kg / h of second water vapor 23. The total steam generated is greater than the quantity required by the reboiler of the carbon dioxide capture unit 2 and an excess of 502 kg / h of steam can be exported.

[0153] The production of hydrocarbon cutting is 177 kg / h.

[0154] Table 1 summarizes the inlet and outlet flow rates of the process units.

[0155] [Tables 1] - Inlet Outlet - 3 4 6 11 16 24 21 Flow rate in kg / h 1283 1331 1208 358 301 571 177

[0156] Requirements: - consumption of water electrolysis unit 5: 5.8 MWe; - heat consumed by the reaction unit of RWGS 8: 0.2 MWth; - heat required to preheat the load (3+7) of unit 8 to 864°C: 0.8 MWth; - Steam at the reboiler of the carbon dioxide capture unit 2: 2103 kg / h.

[0157] Energy recovery: - thermal power released by the combustion unit at 1200°C (with an excess of air of 20%): 0.35 MWth; - Heat recovered during the cooling of the flue gases at the outlet of the combustion unit from 1200°C to 150°C: 0.7 MWth (to partially preheat the load (3+7) at the inlet of unit 8); - steam produced at the heat exchanger 31: 1295 kg / h; - steam produced in the reaction unit FT 13: 1310 kg / h; - electricity production at the first turbine 26: 5 kWe.

[0158] Example 2 according to the invention

[0159] Example 2 conforms to the invention according to [Fig. 1] and illustrates the operation of the sequence of the CO2 capture unit followed by the reaction unit of RWGS 8, then from the FT 13 reaction unit and the hydrogen reaction unit 20, with combustion of part 24 of the gaseous effluent 18 in a total oxy-combustion reaction unit 28 using pure oxygen produced by the water electrolysis unit 5. Burning the gases with pure oxygen avoids the formation of NOx and post-combustion separation. The oxy-combustion effluent 29 is sent directly to the reaction unit of RWGS 8.

[0160] The oxygen flow rate 6 at the inlet of the total oxycombustion reaction unit 28 is 480 kg / h, which corresponds to the stoichiometry of the complete oxidation of all the reactive species, which are dihydrogen, carbon monoxide and the hydrocarbons present, without excess oxygen.

[0161] The total flue gas flow rate feeding the carbon dioxide capture unit 2 is 3641 kg / h. This implies a CO2 capture unit 2 almost half the size of that in Example 1.

[0162] 1706 kg / h of water 4 supplies the water electrolysis unit 5, of which 584 kg / h is water fresh, which allows a saving of 13% weight on the water top-up compared to example 1. The electrical consumption of the water electrolysis unit 5 is 7.4 MWe.

[0163] The quantity of first steam 22 generated by the reaction unit FT 13 is 1893 kg / h. The heat exchanger 31 generates 1822 kg / h (23) of second steam 23 out of the 1025 kg / h required for the operation of unit 2. The steam requirements of the reboiler of the carbon dioxide capture unit 2 are met. A surplus of 2690 kg / h of steam can be exported.

[0164] The thermal power released by the total oxycombustion reaction unit 28, of 1.19 MWth, is supplied to the RWGS reaction unit 8.

[0165] The oxy-combustion effluent 29 exiting the total oxy-combustion reaction unit 28 is at a temperature of 1200°C and is sent with the carbon dioxide-rich effluent 3 to the RWGS reaction unit 8. The preheating requirement for the carbon dioxide-rich effluent 3 is thus reduced: a thermal power of 0.52 MWth is required to preheat the carbon dioxide-rich effluent 3 and the hydrogen stream 7 entering the RWGS reaction unit 8. This requirement can be met by heat exchange with the RWGS gas 9 exiting the RWGS unit, before or after the heat exchanger 31.

[0166] The electricity production at turbine 26 amounts to 6.4 kWe.

[0167] The production of hydrocarbon cutting 21 is 233 kg / h compared to 177 kg / h previously.

[0168] Table 2 summarizes the inlet and outlet flow rates of the process units.

[0169] [Tables2] - Inlet Outlet - 3 4 6 11 16 21 Flow rate in kg / h 717 1706 1548 723 399 233

[0170] Requirements: - consumption of water electrolysis unit 5: 7.4 MWe; - heat consumed by the reaction unit of RWGS 8 at 864°C: 0.22 MWth; - heat required to preheat the load (3+7) of the unit from RWGS 8 to 864°C: 0.52 MWth; - Steam at the reboiler of the carbon dioxide capture unit 2: 1025 kg / h.

[0171] Energy recovery: - heat released by the total oxycombustion reaction unit 28 (from 2074°C to 1200°C): 1.19 MWth; - steam produced at the heat exchanger 31: 1822 kg / h; - steam produced in the reaction unit FT 13: 1893 kg / h; - electricity production at the first turbine 26: 6.4 kWe.

[0172] Example 3 according to the invention

[0173] Example 3 conforms to the invention according to [Fig. 1] and illustrates the operation of the sequence of the CO2 capture unit 2 followed by the RWGS reaction unit 8, then the FT reaction unit 13, and the hydrogen reaction unit 20, with combustion of part 24 of the gaseous effluent 18 in a partial oxy-combustion reaction unit 28 (of the POX type) using pure oxygen produced by the water electrolysis unit 5. In the POX, all the incoming methane is converted and carbon monoxide is formed, which has the advantage of requiring less CO to be produced from the CO2 in the RWGS reaction unit 8. The requirements for H2 produced by electrolysis are reduced, and consequently the water requirements are reduced, from 530 kg / h in Example 2 to 513 kg / h In example 3, the oxycombustion effluent 29 is sent directly to the reaction unit of RWGS 8.

[0174] The oxygen inlet flow rate 6 is 176 kg / h, which corresponds to an oxygenation rate defined as the ratio of the injected molar flow rate to the theoretical oxygen flow rate for complete oxidation of all hydrocarbons present (methane, ethane, propane, ...) of 0.69. This ratio has been adjusted to convert all the methane and limit or even avoid the conversion of other molecules, in particular CO.

[0175] The total flue gas flow rate feeding the carbon dioxide capture unit 2 is 3641 kg / h.

[0176] 1293 kg / h of water 4 supplies the water electrolysis unit 5. Consumption The electrical power of the water electrolysis unit 5 is 5.6 MWe. No additional water is required.

[0177] The quantity of first steam 22 generated by the reaction unit FT 13 is 1880 kg / h. The heat exchanger 31 generates 1670 kg / h (23) of second steam 23 out of the 1025 kg / h required for the operation of unit 2. The steam requirements of the reboiler of the carbon dioxide capture unit 2 are met. An excess of 2525 kg / h of steam can be exported.

[0178] The oxycombustion effluent 29 from the partial oxycombustion reaction unit 28 is sent with the carbon dioxide-rich effluent 3 to the RWGS reaction unit 8.

[0179] The electricity production at turbine 26 amounts to 6 kWe.

[0180] The production of hydrocarbon cutting 21 is equivalent to example 2, i.e. 231 kg / h.

[0181] Table 3 summarizes the inlet and outlet flow rates of the process units.

[0182] [Tables3] - Inlet Outlet - 3 4 6 11 16 21 Flow rate in kg / h 717 1293 1174 388 392 231

[0183] Requirements: - consumption of water electrolysis unit 5: 5.6 MWe; - heat consumed by the reaction unit of RWGS 8 at 864°C: 0.1 MWth; - heat required to preheat the load (3+7) of the unit from RWGS 8 to 864°C: 0.56 MWth; - steam at the reboiler of the carbon dioxide capture unit 2: 1025 kg / h.

[0184] Energy recovery: - heat released by the partial oxycombustion reaction unit 28: 0.0 MWth; - steam produced at the heat exchanger 31: 1670 kg / h; - steam produced in the reaction unit FT 13: 1880 kg / h; - electricity production at the first turbine 26: 6 kWe.

Claims

Demands

1. Device for capturing and converting a feed containing carbon dioxide, comprising the following units: - a carbon dioxide capture unit (2) from the feed (1) adapted to produce a carbon dioxide-rich effluent (3); - a water electrolysis unit (5) adapted to convert water (4) to produce oxygen (6) and hydrogen (7); - a reverse RWGS gas-to-water conversion reaction unit (8) adapted to treat the carbon dioxide-rich effluent (3) with hydrogen (7) and produce an RWGS gas (9) enriched in carbon monoxide and water; - a Fischer-Tropsch reaction unit (13) adapted to convert the RWGS gas (9) and produce an FT effluent (14); - a first separation unit (15) adapted to treat at least part of the FT effluent (14) and produce a hydrocarbon effluent (17), a first water effluent (16), and a gaseous effluent (18);- a partial or total oxycombustion reaction unit (28) adapted to at least partially oxidize the gaseous effluent (18), produce an oxycombustion effluent (29) comprising carbon dioxide and water, and send the oxycombustion effluent (29) to the RWGS reaction unit (8); and - a hydrogen reaction unit (20) adapted to treat the hydrocarbon effluent (17) and produce at least one hydrocarbon cut (21), wherein the partial or total oxycombustion reaction unit (28) is adapted to integrate the reaction section of the RWGS reaction unit (8) within a partial or total oxycombustion chamber (28).

2. Device according to claim 1, wherein the partial or total oxycombustion reaction unit (28) is adapted to produce heat used to supply calories to the carbon dioxide capture unit (2).

3. Device according to any one of the preceding claims, comprising a carbon dioxide separation unit adapted to process RWGS gas (9).

4. Device according to claim 3, wherein the carbon dioxide separation unit is disposed between the RWGS reaction unit (8) and the Fischer-Tropsch reaction unit (13).

5. Device according to any one of the preceding claims, wherein the Fischer-Tropsch reaction unit (13) is adapted to generate a first water vapor (22) to supply thermal energy to the carbon dioxide capture unit (2).

6. Device according to any one of the preceding claims, comprising a first heat exchanger (31) adapted to generate a second water vapor (23) by heat exchange between water and RWGS gas (9).

7. Device according to any one of the preceding claims, comprising a first turbine (26) for treating at least part of the gaseous effluent (18) to produce electricity.

8. Device according to claim 7, wherein electricity is used to supply calories to the RWGS reaction unit (8) and / or the carbon dioxide capture unit (2) and / or the water electrolysis unit (5).

9. Device according to any one of the preceding claims, wherein the water electrolysis unit (5) treats water from a makeup line and / or RWGS gas (9) and / or FT effluent (14).

10. Device according to any one of the preceding claims, wherein the water from the RWGS gas (9) is at least partially or totally separated by a second separation unit (10) to be sent to the water electrolysis unit (5).

11. Device according to any one of the preceding claims, wherein the carbon dioxide-rich effluent (3) is purified before being introduced into the RWGS reaction unit (8).

12. A process for capturing and converting carbon dioxide, comprising the following steps: - treating the feedstock (1) in a carbon dioxide capture unit (2) to produce a carbon dioxide-enriched effluent (3); - converting water (4) in a water electrolysis unit (5) to produce oxygen (6) and hydrogen (7); - treating the carbon dioxide-enriched effluent (3) with hydrogen (7) in a reverse RWGS gas-to-water conversion reaction unit (8) to produce CO₂- and water-enriched RWGS gas (9); - converting the RWGS gas (9) in a Fischer-Tropsch reaction unit (13) to produce FT effluent (14); - treating the FT effluent (14) in a first separation unit (15). to produce at least one hydrocarbon effluent (17), a first water effluent (16) and a gaseous effluent (18); - oxidize at least a portion (24) of the gaseous effluent (18) in a partial or total oxy-combustion reaction unit (28) to produce an oxy-combustion effluent (29) comprising carbon dioxide and water; - send the oxy-combustion effluent (29) to the RWGS reaction unit (8); and - treat the hydrocarbon effluent (17) in a hydrogen reaction unit (20) to produce at least one hydrocarbon cut (21), in which the partial or total oxy-combustion reaction unit (28) is adapted to integrate the reaction section of the RWGS reaction unit (8) within a partial or total oxy-combustion chamber (28).

13. A process according to claim 12, wherein the reaction unit of RWGS (8) comprises at least one reactor used under at least one of the following operating conditions: - temperature between 700°C and 1200°C; - pressure between 0.1 MPa and 10 MPa; - spatial velocity of the gas at the reactor inlet between 5000 NL / kgcata / h and 40000 NL / kgcata / h; - catalyst comprising at least one metal selected from the group consisting of the elements Ni, Cu, Fe, Co, Pt, Pd, Ru, Ag and Au.

14. A process according to claim 12 or claim 13, wherein the reaction unit FT (13) comprises at least one reactor used under at least one of the following operating conditions: - temperature between 170°C and 280°C; - absolute pressure between 1.0 MPa and 6.0 MPa; - catalyst comprising cobalt or iron.

15. A method according to any one of claims 12 to 14, wherein the partial or total oxy-combustion reaction unit (28) comprises at least one reactor used under at least one of the following operating conditions: - absolute pressure between 0.1 MPa and 9 MPa; - temperature between 600°C and 2000°C.

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