Injection of hydrogen produced by water electrolysis onto a sustainable fuel production unit obtained by thermochemical conversion of a carbonaceous plastic feedstock with CO2 valorization by reverse water gas reaction.

Abstract

The invention describes a process for treating a feedstock comprising at least one carbonaceous plastic fraction, which optimally integrates the steps of pretreatment, gasification, Fischer-Tropsch synthesis, water electrolysis, and carbon dioxide-to-hydrogen conversion (RWGS), enabling improved production yields and better energy and economic performance (energy efficiency, production cost, etc.) while complying with environmental constraints such as greenhouse gas emissions imposed at increasingly lower thresholds. Figure to be published: 1

Description

Title of the invention: Injection of hydrogen produced by electrolysis of water onto a unit for the production of sustainable fuels obtained by thermochemical conversion of a carbonaceous plastic feedstock with valorization of CO2 by reverse reaction of the gas with water. technical field

[0001] The invention is in the field of sustainable fuel production, i.e. the use of resources according to the ReFuelEU Aviation rules. Previous technique

[0002] Patent application WO2014 / 068253A1 implements a biofuel production chain from lignocellulosic biomass.

[0003] In this reference scheme illustrated by [Fig. 1], the production of biofuels is carried out in several stages:

[0004] - Step A of biomass pretreatment (1) which is preferably carried out by a drying and roasting stage. Other processes such as pyrolysis can be implemented.

[0005] - Step C of gasification of the pretreated biomass (2) to produce a gas of Synthesis (3), preferably implemented in a flow-through / driven bed gasifier with a cooled wall. Other technologies such as fluidized beds, fixed beds, and plasma can be used. Partial oxidation of the biomass is preferably carried out by a pure oxygen stream (11). The use of high-purity oxygen limits the amount of inert compounds, such as nitrogen, when using air. This oxygen is produced by an air separation unit B.

[0006] - Step D' of adjusting the H2 / CO ratio of the synthesis gas (3) carried out by the reaction water-gas-shift, according to Anglo-Saxon terminology. This step allows the H2 / CO ratio to be adjusted for the downstream synthetic hydrocarbon conversion process.

[0007] - Step D of decarbonation and purification of the synthesis gas (4) to eliminate inert CO2 (12) and capture harmful elements for catalysts used in downstream processes to produce purified synthesis gas (5),

[0008] - Stages E and F of synthetic hydrocarbon production in which one sends The purified synthesis gas (5) in a Fischer-Tropsch synthesis process (E) followed by a hydroconversion process (F) of the produced effluents (6) for the production of biofuels (7). The synthesis gas could also be used by catalytic / biological conversion for the production of methanol, DME, ethanol, alcohols, oxo synthesis, SNG... A portion of the gaseous fraction of the synthesis products Fischer-Tropsch can be combined with the feed at the gasification stage, with the remaining fraction being usable as fuel.

[0009] This patent application describes the possible injection of hydrogen at any point in the process chain. The injected hydrogen is produced by any means known to those skilled in the art, without any particular distinction or integration between the hydrogen production process and the processes in the biofuel production chain.

[0010] One drawback of this implementation is that two steps have a particularly significant impact on performance:

[0011] - The gasification step where part of the feedstock is burned to produce the energy required. Carbon dioxide is formed.

[0012] - The step of adjusting the H2 / CO ratio. This step is done by water-gas-shift It consumes water and carbon monoxide and generates hydrogen and carbon dioxide.

[0013] A loss of yield is observed during the transformation of lignocellulosic biomass into synthetic hydrocarbons.

[0014] US patent 9562196 highlights an adjustment of the hydrogen content at the inlet of the Fischer-Tropsch unit by reforming the naphtha produced by the Fischer-Tropsch synthesis. This option reduces the quantity of finished products produced by consuming the naphtha produced.

[0015] Patent WO 2015 / 101717 describes the addition of external hydrogen to adjust the H2 / CO ratio of a synthesis gas produced by the gasification of a carbonaceous feedstock, and more specifically biomass. This patent claims an adjustment of the synthesis gas production based on the amount of external hydrogen in order to maintain a constant synthetic fuel production.

[0016] The document entitled “A look into the role of e-fuels in the transport system in Europe (2030–2050)” (Concawe Review, Volume 28, Number 1, October 2019) presents the production pathway for decarbonized fuels called “e-fuels” or “power-to-liquids.” These fuels are produced from carbon dioxide, captured from the air or from combustion fumes, which is transformed in the presence of hydrogen by the reverse water-gas shift reaction into carbon monoxide and water. The hydrogen is produced by electrolysis from water. The carbon contained in the carbon dioxide captured from the fumes is not necessarily of biogenic origin. Finally, the dioxide present in the air is so dilute that its extraction requires a significant amount of energy.

[0017] The document “Flexible hybrid process for combined production of heat, power and renewable feedstock for refineries” (2020, Joint Workshop of Task 39 and Task 44, IEA Bioenergy Technology Collaboration Programme) discloses a combination of a lignocellulosic biomass conversion unit and water electrolysis. The conversion of lignocellulosic biomass is carried out in a fixed-bed gasifier after a drying stage. The quality of the resulting synthesis gas necessitates a reforming stage in the presence of a catalyst, carbon dioxide, and oxygen to convert unconverted particles into hydrogen and carbon monoxide. The oxygen produced by electrolysis is sent to the gasifier and the reforming stage. The hydrogen is sent to the Fischer-Tropsch synthesis stage. The recovered CO2 is reinjected into the gasification and reforming stages. A portion of the tail gas is used to produce steam, which is also sent to the gasification stage.

[0018] In the article “Improving carbon efficiency and profitability of the biomass to liquid processus with hydrogen from renewable power” (2018, Fuel 234, 1431-1451, Hillestad et al.), the authors present an integration between a biomass-based synthetic hydrocarbon production unit and water electrolysis. The diagram highlights a step of converting the CO2 produced to the gasification stage by a “Reverse Water Gas Shift” unit. This unit consumes some of the hydrogen produced in a solid oxide electrolysis unit that transforms superheated water vapor at 850°C. Furthermore, the entire output of the gasification section, containing CO and water vapor, is admitted into the “Reverse Water Gas Shift” section, which limits CO2 conversion and requires a significant investment for reactor construction.

[0019] French patent application FR 3029533 A1 describes a thermochemical conversion process for carbonaceous matter in which hydrogen is added downstream of the synthesis gas purification stage, or a mixture of synthesis gas and hydrogen is subjected to a RWGS step. In this document as well, all of the synthesis gas is treated in the RWGS step.

[0020] Patent application WO2022 / 079407 describes a process for synthesizing hydrocarbons from a synthesis gas in which at least a portion of the carbon dioxide and a portion of the hydrogen produced by electrolysis feed a reverse water-gas shift unit to produce a carbon monoxide stream. In the example shown, the volumetric flow rate of hydrogen required for the reaction is more than six times the flow rate of CO2 processed. This results in a significant energy cost for heating the incoming gas streams to the reaction temperature.

[0021] Moreover, the electrolysis process produces an excess of oxygen compared to the needs of the complete chain.

[0022] One of the problems encountered by a person skilled in the art in the field of the invention concerns the improvement of production yields and performance energy and economic efficiency of the production chain on an industrial scale while respecting increasingly stringent environmental constraints.

[0023] In the case of the present invention, the applicant proposes a new process which presents an optimal integration of the steps of pretreatment, gasification, Fischer-Tropsch synthesis, water electrolysis and conversion of carbon dioxide to hydrogen (RWGS) making it possible to achieve improved production yields and better energy and economic performance (energy efficiency, production cost, etc.) while respecting environmental constraints such as greenhouse gas emissions imposed at increasingly lower thresholds. Summary of the invention

[0024] In particular, the present invention relates to a process for converting a feed comprising at least a carbonaceous plastic fraction into hydrocarbons, and producing carbon dioxide that can be used as a by-product, said process comprising and preferably consisting of at least the following steps:

[0025] - possibly a step a) of pre-treatment of the load,

[0026] - a step b) of electrolysis of water into oxygen and hydrogen allowing obtaining a flow of hydrogen, and a flow of oxygen, wherein the water is obtained, at least in part, from a step e) of Fischer-Tropsch synthesis,

[0027] - a step c) of gasification of the feed possibly pretreated in step a), in presence of all or part of the oxygen flux from step b) of water electrolysis so as to obtain a gaseous effluent comprising a synthesis gas,

[0028] - a step d) of removing acidic compounds and impurities from the gaseous effluent comprising a synthesis gas from step c) mixed with a gaseous effluent from step g) after condensation of water vapor, so as to obtain a gaseous effluent comprising a purified synthesis gas and a carbon dioxide stream feeding at least in part a step (g) of carbon dioxide to hydrogen conversion (RWGS),

[0029] - a step e) of Fischer-Tropsch synthesis of the gaseous effluent comprising a gas of purified synthesis from step d) and possibly part of the hydrogen stream from step b) of water electrolysis so as to produce a stream comprising synthetic liquid hydrocarbons, water and at least one gaseous effluent,

[0030] - a hydroconversion step (f) of at least a portion of the flux comprising liquid hydrocarbons from step (e) to produce at least one liquid biofuel cut and at least one gaseous effluent

[0031] - a step (g) of carbon dioxide to hydrogen conversion (RWGS) for produce at least one gaseous effluent comprising carbon monoxide (CO) and of water vapor, wherein the feed entering said step g) comprising at least a part of the hydrogen stream from step b) and a carbon dioxide stream, has at least one of the following two characteristics:

[0032] A / at least a portion of the hydrogen stream from step b) is mixed with the carbon dioxide stream from step (d) and optionally with a carbon dioxide stream from one or more combustion units of the gaseous effluents from steps e) and / or f) and / or optionally a), and optionally with a carbon dioxide stream external to the process, such that the molar ratio of hydrogen to carbon dioxide H2 / CO2 at the inlet of the reactor in step g) of carbon dioxide to hydrogen conversion is adjusted between 1.8 and 3, the molar ratio of hydrogen to carbon monoxide H2 / CO at the inlet of step e) of Fischer-Tropsch synthesis is adjusted by another portion of the hydrogen stream from step b), and / or

[0033] B / The carbon dioxide stream from step (d) is mixed with the hydrogen stream from step b) and a carbon dioxide stream from one or more combustion units of the gaseous effluents from steps e) and / or f) and / or possibly a), and possibly with a carbon dioxide stream external to the process, the mixture of said carbon dioxide streams and the hydrogen stream from step b) feeding the carbon dioxide to hydrogen conversion step (g) (RWGS).

[0034] Said pretreatment steps a), hydroconversion steps f) and carbon dioxide to hydrogen conversion steps g) advantageously comprise one or more combustion unit(s) that can be supplied by at least some of the oxygen from water electrolysis step b) or by an air stream possibly enriched with oxygen from step (b).

[0035] The present invention offers numerous advantages over the prior art; in particular, the proposed invention allows:

[0036] - To improve the carbon yield of said process, in particular by putting into work of the carbon dioxide to hydrogen conversion reaction (RWGS) optimized by the control of the H2 / CO2 ratio and / or by the recycling of carbon dioxide streams from one or more secondary combustion units of gaseous effluents from steps a) and / or e) and / or f) of the process.

[0037] - To improve the yield of the hydrocarbon chain.

[0038] - To reduce the operating costs of said process by using produced oxygen by step b) of electrolysis for gasification and possibly for secondary combustion units,

[0039] - To limit the capacity and therefore the investment of the air separation unit and conversion of carbon monoxide to water (water gas shift according to the terminology) (Anglo-Saxon) depending on the amount of electrolytic hydrogen supplied to the system,

[0040] - To reduce the energy consumption required to achieve the conditions of optimal temperature for the carbon dioxide to hydrogen conversion reaction (Reverse Water Gas Shift according to Anglo-Saxon terminology) and maximize the carbon yield achievable by implementing this step in the chain,

[0041] - To produce a fuel compatible with the objective of reducing emissions of carbon dioxide from advanced biofuels,

[0042] - To reduce the amount of charge required for a production capacity of targeted biofuel.

[0043] - And to reduce the water consumption required in step b) of electrolysis by the recycling of aqueous effluents produced at any stage of said process, including for example water produced in gaseous effluent combustion units.

[0044] In particular, an advantage of the present invention is to provide a process for the production of synthetic hydrocarbons by the indirect thermochemical conversion of a carbonaceous plastic feed allowing the obtaining of an improvement in material yield and an optimization of the scheme by the implementation of a step g) of conversion of carbon dioxide to hydrogen by the Reverse Water Gas Shift reaction according to the Anglo-Saxon terminology, with a flow of hydrogen generated from a flow of water produced by electrolysis (step b).

[0045] Another advantage of the present invention is that it provides a process for recovering the carbon dioxide (CO2) produced in the various stages of the process according to the invention, specifically in step (g) of converting carbon dioxide to hydrogen by the reverse-water gas shift (RWGS) reaction. This benefit makes it possible to limit CO2 emissions and maximize the carbon yield of the chain.

[0046] Another advantage of the present invention lies in the implementation of said step b) of water electrolysis in the process chain according to the invention, which has the following advantages:

[0047] - Use of decarbonized hydrogen (need to use decarbonized electricity) which makes it possible to obtain a fuel whose reduction in greenhouse gas emissions qualifies under the European Red II directive,

[0048] - Adjustment of the H2 / CO molar ratio at the inlet of step e) of Fischer synthesis Tropsch by injecting hydrogen produced in said step b) of water electrolysis. This adjustment allows the carbon monoxide (CO) to be retained in the synthesis gas and increases the material yield and / or reduces the amount of input resources. The injection of hydrogen produced in said step b) of water electrolysis allows for the elimination of all or part of the carbon monoxide-to-water conversion unit (water gas shift according to Anglo-Saxon terminology) present in the prior art process, and therefore eliminates this investment item.

[0049] - The generation of oxygen in said step b) of water electrolysis: oxygen The product can be used in the process according to characteristic B and possibly according to characteristic A as a replacement for the oxygen produced by the air separation unit, thus limiting the investment in the unit. The excess oxygen produced in step b) can advantageously be used: - For the oxidation of hydrogen sulfide (H2S) contained in the effluents of step (d) - For the combustion of gaseous effluents from the process chain - For the combustion of the pretreatment gases produced in step a).

[0050] Another advantage of the invention lies in the use of water produced in any of the process steps, by recycling in step b) of water electrolysis, and in particular water from step e) of Fischer-Tropsch synthesis, water produced by the feed pretreatment step a) of the feedstock, water from the condensate of the combustion fumes from steps (a) and / or (f), and water produced in step g) of carbon dioxide-to-hydrogen conversion (RWGS). This makes it possible to reduce the process water consumption and consequently the operating costs. Description of the figures

[0051] [Fig.1]

[0052] Figure 1 represents the prior art reference diagram WO2014 / 068253A1 and the associated comparative example 1

[0053] [Fig.2]

[0054] Fig. 2 represents the different stages of the production process according to the invention.

[0055] [Fig.3]

[0056] Fig. 3 represents the main flows in Example 2 illustrating the characteristics A + B according to the invention (H2 / CO2 = 2 at the RWGS inlet) with CO2 recycling from the combustion unit of stage F to block G.

[0057] In the sense of the present invention, the different embodiments presented can be used alone or in combination with each other, without limitation of combination.

[0058] In the sense of the present invention, the different parameter ranges for a given step, such as pressure ranges and temperature ranges, can be used alone or in combination. For example, in the sense of the present invention, a preferred range of pressure values ​​can be combined with a more preferred range of temperature values.

[0059] In the following text, the expressions "between ... and ..." and "between ... and ..." are equivalent and mean that the limit values ​​of the interval are included in the range of values ​​described. If this were not the case and the limit values ​​were not included in the range described, such clarification will be provided by the present invention.

[0060] In this description, the expression "greater than..." is understood as strictly greater than, and symbolized by the sign ">", and the expression "less than" as strictly less than, and symbolized by the sign "<". Description of the implementation methods

[0061] The present invention relates to a method for converting a feed comprising at least a carbonaceous plastic fraction into renewable hydrocarbons.

[0062] Charges

[0063] The carbonaceous plastic fraction treated in the process according to the invention may comprise any plastic filler.

[0064] Plastic filler means a filler comprising one or more polymers, and which may contain other compounds, such as additives of organic or inorganic origin and / or impurities from use, particularly those arising from the life cycle of plastic materials and objects, and / or from the waste collection and sorting process. For example, impurities from use may be metallic, organic, or mineral; they may include packaging residues, food residues, or compostable residues (biomass). Impurities from use may also include glass, wood, cardboard, paper, household, chemical, or cosmetic products, used oils, and water.

[0065] Preferably said carbon plastic fraction comprises one or more polymers selected from thermoplastic polymers, thermosetting polymers, elastomers, alone or in mixture.

[0066] Thermoplastic polymers are advantageously chosen from among polyolefins, for example polyethylene, polypropylene or olefin copolymers such as ethylene / vinyl acetate copolymers; polyvinyls, for example polyvinyl chloride, polyvinyl alcohol, polyvinyl acetate, polyvinylidene chloride, polybutyral or polyformal vinyl; polystyrenes such as polystyrene and various styrenic copolymers, polymethyl methacrylate or polyacrylonitrile; polyamides; polycarbonates; cellulosic polymers such as cellulose acetate or cellulose nitrate; linear polyesters such as polyethylene terephthalate, polybutylene terephthalate, polytetramethylene terephthalate; and polyfluorethens such as polytetrafluorethene (PTFE) and polychlorotrifluoroethylene. (PCTFE) and polyfluoride vinylidene (PVDF), polyacetals such as polyoxymethylene, polysulfones, polyphenylene sulfide, modified polyoxyphenylene.

[0067] Thermosetting polymers are advantageously chosen from unsaturated polyesters, phenoplasts such as phenol-formaldehyde resins, aminoplasts such as urea-formaldehyde or melamine-formaldehyde, polyepoxides, polyimides, polyurethanes.

[0068] The elastomers are advantageously chosen from natural rubber, synthetic polyisoprene, polybutadiene, styrene-butadiene copolymers, polyisobutylene, isobutylene-isoprene copolymers, neoprene, butadiene-acrylonitrile copolymers, ethylene-propylene copolymers, ethylene-propylene-diene terpolymers, amide block polyethers, polyacrylic elastomers, ethylene acrylic copolymers, epichlorohydrin elastomers.

[0069] The carbonaceous plastic fraction treated in the process may advantageously be derived from the recycling of solid municipal waste, industrial polymers, or household plastics. The plastic feedstock for the process may advantageously be a mixture of solid or liquid feedstocks.

[0070] Said carbonaceous plastic fraction converted in the process according to the invention may advantageously further comprise a fraction of another gaseous, solid and / or liquid hydrocarbon feedstock. The hydrocarbon feed fraction is understood within the scope of the present invention as a feed that may advantageously contain at least coal, petroleum coke (petcoke in Anglo-Saxon terminology), natural gas, petroleum residues, crude oils, decapitated crude oils, deasphalting asphalts, derivatives of petroleum conversion processes (such as, for example: FCC HCO / Slurry, heavy GO / VGO from coking, residue from visbreaking or similar thermal processes, etc.), oil sands or their derivatives, shale gas and oil shale or their derivatives, liquid biomass (such as, for example: rapeseed oil, palm oil, pyrolysis oil, etc.)), of biomass in slurry according to Anglo-Saxon terminology, corresponding to a mixture of liquid biomass with a solid hydrocarbon feedstock.

[0071] Preferably, the feed treated in the process according to the invention comprises and is preferably made up of a carbon-based plastic fraction.

[0072] In another embodiment, the feed treated in the process according to the invention comprises and is preferably made up of a carbonaceous plastic fraction and a fraction of another gaseous, solid and / or liquid hydrocarbon feed as defined above.

[0073] Generally, the charge used in the process of the invention comprises at least 10% and preferably at least 20%, preferably at least 50%, of preferred method at least 70%, and more preferred method at least 90% of plastic fraction.

[0074] In the case of a feed converted in the process comprising another hydrocarbon feed, the mass fraction of lignocellulosic biomass in the feed converted in the process according to the invention is less than 10% and preferably less than 5% by weight.

[0075] The different stages of the process according to the invention are described below.

[0076] Step a) optional

[0077] The process may advantageously include a step a) of pretreatment of the feed.

[0078] Step a) of pretreatment of the feed allows the production of a pretreated feed and at least one gaseous effluent.

[0079] Preferably, the pretreatment step comprises at least one of the following operations: drying (a1), roasting (a2), gas combustion (a3), or grinding (a4). Preferably, the pretreatment step (a) comprises a drying operation (a1), a roasting operation (a2), a gas combustion operation (a3), and a grinding operation (a4). In this case, the feed pretreatment step (a) produces a roasted feed and at least one gaseous effluent.

[0080] In an embodiment where the load used is already dry, the pretreatment step includes a roasting operation a2), gas combustion a3) and a grinding operation a4).

[0081] When the hydrocarbon feed fraction is a gaseous or liquid hydrocarbon feed fraction, it is advantageously introduced directly into step c) of gasification without being subjected to step a) of pretreatment.

[0082] al) Drying operation

[0083] Step a) of pretreating the feed may advantageously include a drying operation a1) of the feed, advantageously carried out at a temperature between 20 and 180°C, preferably between 60 and 160°C, and preferably between 100 and 140°C, for a duration between 5 and 180 minutes, and preferably between 15 and 60 minutes. At the start of the drying operation a1), the feed generally has a moisture content between 15 and 80% by mass. The residual moisture content in the feed after the drying operation is advantageously less than 25% by mass, preferably less than 15% by mass, and more preferably less than 10% by mass. The drying operation may be carried out by any means known to those skilled in the art.

[0084] The energy required for drying is generally supplied by bringing the load into contact with a flow of hot gas.

[0085] a2) Heat treatment operation

[0086] Step a) of pretreatment of the charge may include a heat treatment operation a2), preferably of the dried charge resulting from the drying operation al).

[0087] Step a2) of thermal treatment allows the production of a solid effluent and a gaseous effluent called pretreatment gas.

[0088] Advantageously, the heat treatment operation can be a roasting operation.

[0089] The roasting operation a2) can be carried out in a roasting oven which produces a solid roasted feedstock effluent that is more friable and therefore requires less energy to be finely ground to obtain a roasted effluent. The roasting operation is advantageously carried out at a temperature between 220 and 350°C, preferably between 250 and 320°C and more preferably between 270 and 300°C for a duration of between 5 and 180 minutes, and preferably between 15 and 60 minutes, at an absolute operating pressure preferably between 0.01 and 1.5 MPa, preferably between 0.01 and 1.0 MPa and more preferably between 0.05 and 0.15 MPa. The roasting operation is carried out in an environment where the oxygen content is advantageously less than 10% by volume, preferably less than 8% by volume and preferably less than 3% by volume.

[0090] The heat treatment operation has the advantage of reducing the energy cost of the grinding operation (a3) ​​and is accompanied by a dry matter loss of between 5 and 40% by mass, preferably between 10 and 35% by mass. However, this dry matter loss is accompanied by a much more limited loss of calorific value, on the order of 5 to 20%. As such, the heat treatment operation makes it possible to increase the volumetric energy content of the feed, that is to say, its energy per unit volume.

[0091] The energy required for the thermal treatment operation a2) is supplied by the combustion of the pretreatment gas, possibly supplemented by the combustion of auxiliary gas, which may be natural gas or preferably part or all of the gaseous effluents from step e) and / or f).

[0092] a3) Gas combustion section

[0093] Said pretreatment step a) advantageously comprises one or more gas combustion units, preferably for pretreatment gases produced in said step a) and preferably in the heat treatment operation a2), in which said gases are burned in a combustion step to produce combustion fumes containing carbon dioxide. These combustion fumes can advantageously be used as a hot gas stream to provide the energy required for the drying operation a1) and the heat treatment operation a2). In the case where the energy provided by the combustion of the pretreatment gases is not sufficient for the thermal requirements of step a), said combustion step may advantageously be supplemented by the implementation in said step a) of an auxiliary gas combustion step, which may be natural gas and / or part or all of the gaseous effluents from step e) and / or f). The excess energy contained in the combustion fumes may be used to produce steam at different pressure levels according to the requirements of the various steps of the process.

[0094] In the case where an auxiliary gas combustion step is also implemented in said step a), the combustion steps of the pretreatment gas on the one hand and of the auxiliary gases on the other hand can be carried out in a common combustion unit or in two separate combustion units, each of the units being able to be supplied either with air, or with part of the oxygen flow from step b) or by a mixture of air and oxygen from step b) in any proportions.

[0095] According to a preferred embodiment of the invention, the combustion unit(s) of said pretreatment step a) can be supplied with at least some of the oxygen from the water electrolysis step b).

[0096] In another embodiment, the combustion unit(s) of said pretreatment step a) may be supplied by an airflow optionally enriched in oxygen from step (b).

[0097] In these last two embodiments, the combustion unit(s) advantageously include a flue gas cooling stage that separates carbon dioxide from water vapor by condensation. In the case of combustion using air, the combustion section may optionally be supplemented by a process for separating carbon dioxide from nitrogen contained in said flue gases, this separation being carried out by the use of chemical or physical solvents, a mixture of chemical and physical solvents, or any other means known to those skilled in the art.

[0098] According to a preferred embodiment of feature B of the invention, the carbon dioxide stream produced by the combustion unit(s) of said pretreatment step a) feeds the feed of step (g), mixed with the carbon dioxide stream from step (d) and the hydrogen stream from step b).

[0099] In a preferred embodiment, the carbon dioxide stream produced by the combustion of the pretreatment gas from step a) feeds the feed of step (g), mixed with the carbon dioxide stream from step (d) and the hydrogen stream from step b).

[0100] More generally, all or part of the carbon dioxide stream produced by the combustion unit(s) of the pretreatment stage can be used as a by-product of the process that can supply a transport network, a storage unit or any carbon dioxide recovery facility external to the process.

[0101] Advantageously, the water formed in the combustion unit(s) of step a) of wet feed pretreatment is partially or totally sent to step b) of electrolysis. Recycling the water formed in step a) to step b) reduces the operating costs of the process according to the invention.

[0102] In one embodiment, the water formed during pretreatment step a) advantageously undergoes a treatment step before being recycled in water electrolysis step b) so as to obtain the required specifications of step b). The treatment step may advantageously consist of removing oxygenated compounds from the water formed during step a).

[0103] More generally, the water produced in any of the process steps, and preferably the water produced in the combustion unit(s) of the wet feed pretreatment step a) and / or the hydroconversion step f), preferably by condensation of the combustion fumes from said combustion units, the water produced in the Fischer-Tropsch synthesis step e), and the water produced in the carbon dioxide to hydrogen conversion (RWGS) step g), is recycled in the water electrolysis step b).

[0104] a4) Grinding operation

[0105] Step a) of pretreatment of the feed can also advantageously include a grinding operation a4), preferably of the roasted effluent from operation a2).

[0106] The grinding operation a4) can be carried out under conditions allowing a reduction of the feedstock and preferably of the roasted effluent from operation a2) into particles of a size suitable for treatment in an entrained flow gasification unit (step c). At the end of the grinding operation a4), 90% of the feedstock particles preferably have an equivalent diameter of less than 300 microns and 90% of the feedstock particles preferably have an equivalent diameter greater than 1 micron; preferably 90% of the feedstock particles have an equivalent diameter less than 200 microns and 90% of the feedstock particles have an equivalent diameter greater than 5 microns; and more preferably 90% of the feedstock particles have an equivalent diameter less than 100 microns and 90% of the feedstock particles have an equivalent diameter greater than 10 microns.The equivalent diameter, denoted "of", is defined for example according to the following relationship: .

[0107] of=V / S

[0108] with V being the volume of the particle,

[0109] S the surface of the sphere of the same volume as the particle.

[0110] In a particular embodiment, the grinding operation a4) can be carried out in the presence of a second feedstock so that it is ground simultaneously in a single mill. When said second feedstock is fossil, then it can be chosen from solid fossil hydrocarbons such as coal, petroleum coke (petcoke according to Anglo-Saxon terminology).. An advantage of carrying out the grinding in the presence of a second feed is to allow for the efficient grinding and drying of said second feed.

[0111] Preferably, the grinding operation a4) can be carried out in the presence of an additional compound useful for the subsequent gasification step, said compound being chosen from vitrified ashes, sand, limestone, lime or other compounds known to the person skilled in the art taken alone or in mixture.

[0112] Preferably, the mill is chosen so as to optimize the pneumatic transport of the powder obtained at the end of operation a4), minimizing the minimum fluidization velocity (UMF), as well as its own energy consumption.

[0113] Preferably, said co-crushing operation a4) is carried out in a roller mill, universal mill, attrition mill, or any other type of mill known to those skilled in the art

[0114] Electrolysis step b)

[0115] According to the invention, the process according to the invention comprises a step b) of electrolysis of water into oxygen and hydrogen allowing the obtaining of a flow of hydrogen, and a flow of oxygen, in which the water is obtained, at least in part or in whole, from a step e) of Fischer-Tropsch synthesis.

[0116] According to one embodiment of the invention, the water is obtained from at least one or more steps of the process producing water and is recycled to supply said step b). According to the invention, the water is advantageously obtained at least in part from step e) of Fischer-Tropsch synthesis, and can also advantageously be obtained from step g) of conversion of CO2 to hydrogen and / or possibly from the condensates of the various combustion fumes from steps a) and / or f) and / or from the gaseous effluent from step a) of pretreatment of the feed and preferably from operation al) of drying.

[0117] According to the invention, the oxygen flow obtained at the end of step b) is sent in part or in whole to step c) of gasification.

[0118] According to a preferred embodiment of the invention, the oxygen flow obtained at the end of step b) is also sent at least in part to one or more gaseous effluent combustion units included in steps (a) and / or (f) of the process.

[0119] Advantageously, the oxygen produced by the electrolysis of water has a purity of at least 98.5% by weight (on a dry basis). The impurities that may be present in the oxygen produced are water and / or hydrogen.

[0120] According to the invention, all or part of the hydrogen stream obtained at the end of step b) of electrolysis is sent to step g) of conversion of CO2 to hydrogen.

[0121] According to one embodiment of the invention, part of the hydrogen flow obtained at the end of step b) of electrolysis is sent to step e) of Fischer-Tropsch synthesis.

[0122] Another part of the hydrogen stream obtained by electrolysis can advantageously be sent to the hydroconversion step f) of the stream comprising liquid hydrocarbons from the Fischer-Tropsch synthesis step (e).

[0123] Advantageously, the hydrogen stream obtained from step b) of electrolysis and sent to step e) of Fischer-Tropsch synthesis has a purity of at least 99.8% by weight (on a dry basis). Preferably, the hydrogen sent to step e) contains less than 100 ppm of oxygen and / or water, preferably less than 60 ppm, preferably less than 40 ppm, preferably less than 30 ppm, and preferably less than 15 ppm.

[0124] According to feature A of the invention, the molar ratio between hydrogen and carbon monoxide H2 / CO at the inlet of step e) of Fischer-Tropsch synthesis is adjusted by another part of the hydrogen flow from step b).

[0125] Advantageously, the molar ratio of hydrogen to carbon monoxide, denoted H2 / CO, of the effluent introduced in step e) of Fischer-Tropsch synthesis is between 0.5 and 4, preferably between 1 and 3, more preferably between 1.5 and 2.5 and most preferably equal to 2.1, the hydrogen advantageously coming partly from step d) of removal of acidic compounds and impurities from the synthesis gas effluent and partly from step b) of electrolysis of water.

[0126] According to characteristic B of the invention, the molar ratio between hydrogen and carbon monoxide, denoted H2 / CO of the effluent introduced in step e) of Fischer-Tropsch synthesis is advantageously between 0.5 and 4, preferably between 1 and 3, more preferably between 1.5 and 2.5 and most preferably equal to 2, the hydrogen advantageously coming in part or in whole from step d) of removal of acidic compounds and impurities from the synthesis gas effluent and / or in part or in whole from step b) of electrolysis of water.

[0127] Step b) of water electrolysis can be carried out by any means known to those skilled in the art, for example by alkaline electrolysis, by proton exchange membrane, by anion exchange membrane, or by solid oxide electrolysis.

[0128] An advantage of step b) of water electrolysis is to produce decarbonized hydrogen which can be used to obtain a fuel whose reduction in greenhouse gas emissions is eligible under the European Red III directive.

[0129] Another advantage of recycling water from pretreatment step a) and / or Fischer-Tropsch synthesis step e) and / or CO2 to hydrogen conversion step g) and / or combustion fumes from step f) to electrolysis step b) is to reduce process water consumption and consequently operating costs.

[0130] Another advantage of step b) electrolysis is that all or part of the oxygen produced is used in the process in step c) gasification, thus limiting or even eliminating the need for an air separation unit and reducing investment and operating costs. Furthermore, excess oxygen can be advantageously used for treating SRU / TGTU tail gases (for Sulfur Recovery Unit / Tail Gas Treating Unit) and / or for burning fuel gas from the unit and residual gas and / or for burning pretreatment gases.

[0131] Gasification step c)

[0132] The process according to the invention includes a step c) of gasification of the feed, optionally pre-treated in step a), in the presence of all or part of the oxygen stream from step b) of water electrolysis so as to obtain a gaseous effluent comprising a synthesis gas.

[0133] The gasification step implements a partial oxidation reaction that converts the feed into a synthesis gas consisting mainly of carbon monoxide and hydrogen. The gasification step is advantageously carried out in the presence of a controlled quantity of an oxygen stream, obtained in whole or in part from step b) of electrolysis, in the form of an oxygen stream having a purity of at least 98.5% by weight (on a dry basis). The use of this oxygen stream makes it possible to limit the quantity of inert compounds, such as nitrogen when using air as the oxygen source. This limits the accumulation of inerts and therefore the problems related to pressure or velocity losses, and thus reduces the size of the equipment used, further limiting the investment and operating costs of the process.

[0134] Advantageously, the gaseous effluent corresponding to the synthesis gas from step c) of gasification is composed mainly of water (H2O), carbon monoxide (CO), hydrogen (H2), and carbon dioxide (CO2), and may include impurities from the feed.

[0135] According to the invention, the oxygen flow implemented in the gasification step is derived in whole or in part from step b) of water electrolysis.

[0136] Advantageously, an oxygen stream from an air separation step can also be used in step c) of gasification, in addition to the oxygen stream from step b) of water electrolysis.

[0137] In a particular embodiment, the entire flow of oxygen introduced in the gasification step c) comes from the water electrolysis step b).

[0138] Step c) of gasification of the feed is carried out in a fixed bed gasifier, or fluidized bed gasifier, or preferably in a high-temperature cooled wall driven-flow gasifier, i.e. at a temperature between 800 and 1800°C, preferably between 1000 and 1600°C and more preferably between 1200 and 1500°C and at An absolute pressure advantageously between 2 and 12 MPa, preferably between 2.5 and 6.0 MPa, and more preferably between 3.0 and 5.0 MPa. The high temperature allows for a high carbon conversion rate and therefore reduces the amount of unconverted carbon in the ash produced, thus facilitating its disposal or recovery by reducing the need for recycling to the gasifier.

[0139] The entrained-flow gasifier is preferably a gasifier known to those skilled in the art as a cooled-wall entrained-flow gasifier. The cooled wall delimits the gasification chamber, which is itself located within the gasifier. The water used to cool the wall of the gasification chamber circulates in a coil placed outside the wall of the gasification chamber. The water is partially vaporized, thus generating a medium-pressure steam flow. This cooling of the walls allows the formation of a protective ash layer on the inner wall of the gasification chamber. Indeed, the feedstocks introduced into the gasifier contain inorganic compounds, which form ash after gasification. At the gasification temperature, this liquid ash, in the form of droplets, solidifies upon contact with the cooled wall and forms a solid layer that acts as insulation.Thus, the thermal protection of the gasification chamber wall is ensured, on the one hand, by a layer of solidified ash and, on the other hand, by a layer of molten ash in contact with the gas phase, flowing towards the bottom of the gasifier. The combustion chamber wall is therefore highly resistant to high temperatures and significant temperature variations. Furthermore, due to their composition, particularly their high content of alkaline compounds, the ash is corrosive to refractory linings. Consequently, gasification technologies using internal refractories for wall protection are difficult to operate because of their rapid deterioration, necessitating frequent replacement. In addition, refractories are very sensitive to thermal shock, which destroys this protective layer through fracturing.

[0140] In the cooled-wall driven-flow gasifier, at least two burners, and preferably four or more depending on the gasifier's capacity, are arranged in the gasification chamber, the walls of which are cooled and which operate at a temperature sufficient to allow the melting of the ash contained in the feed. Furthermore, the feeds introduced into the gasifier can have very different properties. Thus, the melting point of the ash can vary depending on the composition of the feed introduced into the gasification chamber. Similarly, the minimum gasification temperature required to remain above the ash melting point can be adjusted by varying the nature of the feeds, which have different properties, and the proportions of the different constituents, and / or by injecting a fluxing agent (for example, limestone) with the feed.

[0141] In a preferred embodiment of the invention, the syngas produced in the gasification chamber exits the chamber concurrently with the liquid ash flowing to the bottom of the gasifier. This concurrent configuration has the advantage, compared to a configuration where the syngas is discharged from the gasification chamber upwards while the liquid ash flows downwards, of avoiding the risk of blockages in the liquid ash discharge line. Indeed, liquid ash flowing alone in the line can, depending on its viscosity, flow with difficulty and / or partially solidify, partially or totally obstructing the discharge line and leading to a shutdown of the installation for maintenance. These phenomena can occur particularly during transient phases of temperature increases or decreases, or during adjustments related to a change in the nature of the feedstock.The configuration according to the invention has the advantage that the gas flowing co-currently with the liquid ash in the discharge pipe of the gasification chamber facilitates the flow of this ash towards the bottom of the gasifier and avoids the risk of blockages even in transient phases.

[0142] In a preferred embodiment of the invention, the syngas and liquid ash pass through an intensive liquid quench zone in contact with at least one water film as described in patent application DE 102007044726. This quench zone is positioned below the gasification chamber and separates a hot, dry zone at the top from a cooler, wetter zone at the bottom. The hot, dry zone below the gasification chamber is characterized by the presence of syngas and liquid ash flowing to the bottom of the gasifier. The cooler, wetter zone is located below the hot, dry zone and is characterized by the presence of water-saturated syngas, solidified ash, and liquid water. The temperature of the syngas at the outlet of the cold, wet zone corresponds to the thermodynamic equilibrium temperature between the gas and liquid phases at the operating pressure of the gasifier.

[0143] This quench configuration allows for a strong removal of the fine, sticky ash particles carried along during the synthesis gas scrubbing, thus reducing the risk of fouling in the piping and downstream units. Furthermore, the high temperature in the gasification chamber allows the molten ash to flow easily downwards down its wall before falling into the quench zone. After passing through the cold, humid unit, the cooled ash ends up at the bottom of the water-filled gasifier. Upon contact with the water, this molten ash is immediately cooled and vitrified into dense particles. These particles are then extracted from the gasifier as a mixture of water and solid ash (or slurry) by depressurization. The majority of the mineral compounds contained in the feedstock form the molten ash. This This configuration allows for the advantageous encapsulation of hazardous products such as heavy metals within vitrified ash. The vitrification process renders this ash highly stable and impervious to leaching.

[0144] In an alternative embodiment of the invention, the produced syngas exits the gasification chamber from the top, while the molten ash flows down the wall counter-currently to the bottom of the water-filled gasifier. Upon contact with the water, the molten ash solidifies abruptly, forming small particles. These particles are then extracted from the gasifier as slurry (a mixture of water and solid ash) by depressurization. Since most of the mineral compounds contained in the feedstock form the molten ash, this configuration advantageously allows for the encapsulation of hazardous products such as heavy metals within the vitrified ash. The vitrification process renders this ash highly stable; it is not leachable.The syngas exiting the gasification chamber from the top, along with the finest molten ash particles carried with it, is cooled by a stream of chilled syngas free of solid particles. This cooling process solidifies the molten ash into non-sticky solid particles. After this initial cooling stage, the syngas is directed to a heat exchanger to produce steam. To remove the remaining fine solid particles, the syngas then passes through a gas-solid phase separation section using any technique known to those skilled in the art, such as cartridge filters. A portion of this cooled, particle-free syngas is recycled back to the gasifier outlet to cool the syngas exiting the top of the gasifier.

[0145] Step d) of removing acidic compounds and impurities from the synthesis gas

[0146] The process according to the invention includes a step d) of removing acidic compounds and impurities from the gaseous effluent comprising a synthesis gas from the gasification step c) so as to obtain a gaseous effluent comprising a purified synthesis gas and a carbon dioxide stream.

[0147] The synthesis gas produced in step c) of gasification is composed mainly of carbon monoxide (CO), hydrogen (H2), carbon dioxide (CO2), and water (H2O), and may include impurities initially present in the feedstock. These impurities are essentially metals, particularly alkali metals (Na, K), sulfur compounds, as well as chlorinated and nitrogenous compounds. In particular, the halogenated compounds initially present in the feedstock according to the invention may reach concentrations of at least 250 ppm by mass in the crude feedstock fraction (before drying).

[0148] Preferably, step d) comprises, preferably consists of, steps d1) and / or d2), and / or d3), d4), d5) and / or d6).

[0149] Step d1) of washing the synthesis gas with water

[0150] Preferably, step d) includes a water washing step dl) to remove traces of solids from the synthesis gas as well as some of the water-soluble gaseous compounds. This operation can be carried out by any type of technique known to those skilled in the art, including a water scrubber with a venturi effect, a scrubber column with all types of internals, etc.

[0151] Preferably, at the outlet of the water washing step, the synthesis gas is subjected to a step d2) of catalytic hydrolysis of the COS and HCN compounds contained in the effluent from step d1) into H2S and NH3.

[0152] Step d2) of catalytic hydrolysis of COS and HCN compounds

[0153] Preferably, step d) includes a step d2) of catalytic hydrolysis of the COS and HCN compounds of the gaseous effluent comprising the synthesis gas from step d1).

[0154] The effluent from step d1) is subjected to a step d2) of catalytic hydrolysis of COS and HCN to H2S and NH3, resulting in a purified effluent. This step allows the removal of COS and HCN, which are poisons for the Fischer-Tropsch synthesis catalyst. The step d2) of catalytic hydrolysis of carbon oxysulfide (COS) and hydrogen cyanide (HCN) is, according to the invention, advantageously carried out in the presence of a catalyst containing a platinum-based compound, or an oxide of an element selected from the group comprising titanium, zirconium, aluminum, chromium, zinc, or a mixture thereof.

[0155] Preferably, the hydrolysis catalyst is a titanium oxide-based catalyst. The catalyst used may also contain at least alkali metals, alkaline earth metals, and / or rare earth elements, derived, for example, from precursors such as potash, zirconium oxide, sodium or barium carbonate, sodium or barium bicarbonate, calcium sulfate, sodium or barium acetate, and sodium or barium oxalate. The hydrolysis step is advantageously carried out at a temperature between 100 and 400°C, preferably between 200 and 350°C.

[0156] Advantageously, the effluent at the outlet of the hydrolysis unit of step d2) contains less than 25 ppm volume of COS and less than 5 ppm volume of HCN, preferably less than 10 ppm volume of COS and less than 1 ppm volume of HCN, and more preferably less than 5 ppm volume of COS and less than 0.1 ppm volume of HCN.

[0157] In a variant of the process according to the invention, the effluent from the carbon monoxide to steam conversion step d3) is at least partially sent in a mixture with said complementary part to the catalytic hydrolysis step of COS and HCN into H2S and NH3 (step d4). Advantageously, the effluent from the carbon monoxide to steam conversion step d3) is sent in a mixture with said complementary part to the catalytic hydrolysis step (step d4) after cooling to a temperature preferably between 100 and 400°C, preferably between 200 and 350°C.

[0158] Step d3) of washing with water

[0159] Preferably, step d) includes a step d3) of washing with water the effluent obtained at the end of step d2). Step d3) makes it possible to remove impurities such as NH3 and HCl which are soluble in water and particularly harmful to the operation of step d4) of removing acid gases.

[0160] In a variant of the process according to the invention, the effluent obtained at the end of step d2) may be pre-treated with a heavy metal removal step on at least one suitable guard bed. This removal step makes it possible to substantially remove heavy metals, such as lead, arsenic, and mercury, before the effluent is treated in step d3) of water washing and, more particularly, before step d4) of acid gas removal. Fixed-bed reactor technology will advantageously be preferred for capturing the heavy metals contained in the synthesis gas using capture media known to those skilled in the art. Advantageously, the removal step is carried out on at least one or more guard beds in the presence of one or more capture media containing one or more active phases.Advantageously, said active phases contain at least one sulfur compound, such as, for example, supported elemental sulfur, and / or a metallic sulfide such as copper and / or zinc sulfide, and at least one precious metal such as silver, gold, or palladium, and / or a silver-exchanged zeolite, and / or oxides of transition metals such as, for example, copper or nickel oxides. Advantageously, said active phase(s) are supported, for example, on alumina, silica, silica-alumina, or activated carbon.

[0161] Advantageously, passing the effluent through at least one guard bed of the removal stage makes it possible to achieve the required specifications at the inlet of the acid gas removal stage d4 (stage d4), as well as the required specifications for the Fischer-Tropsch synthesis unit of stage e).

[0162] In a second embodiment according to the invention, the heavy metal removal step is carried out between step d3) of water washing and step d4) of acid gas removal.

[0163] In a third embodiment according to the invention, the heavy metal removal step is carried out after step d4) of acid gas removal when the solvent used in step d4) is a chemical solvent derived from an alkanolamine, known to man of the trade to be less sensitive than physical solvents to the presence of heavy metals.

[0164] At the outlet of the heavy metal removal step, the effluent generally has a content of less than 1 ppb volume of lead, arsenic and mercury, preferably less than 0.5 ppb volume, more preferably less than 0.1 ppb volume and even more preferably less than 0.01 ppb volume of lead, arsenic and mercury.

[0165] Step d4) of acid gas separation

[0166] Step d4) is dedicated to the separation of acidic gases such as sulfur compounds (H2S) or CO2 remaining in the gaseous effluent comprising the synthesis gas from step d3), as well as to the separation of the CO2 remaining in the gaseous effluent from step (g). The gaseous effluent comprising the synthesis gas from step d3 and the gaseous effluent from step g) can advantageously feed the same separation unit after a recombination step d5) located upstream of step d4), or preferably two separate separation units. The use of a separate CO2 separation unit for the effluent from step g) can have the advantage of operating the two units independently, maintaining a smaller size for the unit separating the CO2 and the sulfur compounds contained in the effluent from step d3).

[0167] Step d4) is carried out by using chemical or physical solvents, a mixture of chemical and physical solvents, or any other means known to those skilled in the art. The chemical solvent may be, for example, a primary, secondary, or tertiary amine derived from an alkanolamine, such as monoethanolamine (MEA), diethanolamine (DEA), or methyldiethanolamine (MDEA), or a mixture of several amines. The physical solvent may be, for example, based on mixtures of polyethylene glycol (PEG) dialkyl ethers, such as PEG diethyl or dibutyl ethers, or methanol.

[0168] The acid gas removal step is, for example, carried out using an acid gas absorption column with the chemical or physical solvent used, followed by a solvent regeneration step to reduce solvent consumption in the unit. This regeneration step can advantageously be carried out in two stages to remove, on the one hand, a gas stream rich in CO2 and, on the other hand, a gas stream rich in H2S. The CO2-rich gas stream from the regeneration step of the acid gas separation unit, fed at least in part by the effluent from step d3), contains significant quantities of H2S, COS, and possibly traces of solvent, which must be removed by any means known to those skilled in the art, for example, on at least one guard bed based on zinc oxide (ZnO), Cu / ZnO, or activated carbon, and allows the required specifications to be met. in terms of impurities in the carbon dioxide stream introduced in step g) of CO2 to hydrogen conversion.

[0169] More generally, all or part of the carbon dioxide stream produced by step d4) can be used as a by-product of the process to supply a transport network, a storage unit or any carbon dioxide recovery facility external to the process.

[0170] Recombination step d5)

[0171] In the case where the separation of CO2 from the gaseous effluents from step g) and step d3) is carried out in two separate units, the synthesis gases comprising H2 and CO from said separation steps are recombined at step d5) upstream of step d6).

[0172] Otherwise illustrated in the following examples, the gaseous effluent from step g) is recombined with the gaseous effluent from step d3) at step d5) upstream of the common separation step d4).

[0173] Step d6) of final purification

[0174] Preferably, step d) includes a final purification step d6) to obtain a gaseous effluent comprising purified syngas. Indeed, the cobalt-based catalyst used in step e) of the Fischer-Tropsch synthesis is highly sensitive to impurities present in the syngas, which are therefore only tolerated in quantities on the order of ppb (parts per billion). At the outlet of step d4) or d5), the syngas may still contain impurities at concentrations of approximately 100 ppb by volume of H2S and COS.

[0175] Advantageously, the final purification step d6) is carried out on at least one guard bed and can be implemented to completely adsorb the last traces of impurities remaining in the gaseous effluent comprising the synthesis gas, such as halogenated compounds, H2S, COS, HCN and NH3. The final purification step d6) is carried out by any means known to those skilled in the art, for example on at least one guard bed based on zinc oxide ZnO, Cu / ZnO, activated carbon, and makes it possible to achieve the required specifications in terms of impurities in the synthesis gas implemented in the Fischer-Tropsch synthesis step e).

[0176] Advantageously, at the outlet of step d6), the gaseous effluent comprising a purified synthesis gas has a sulfur content of less than 100 ppb by volume, preferably less than 50 ppb by volume, more preferably less than 10 ppb by volume; an HCN content of less than 100 ppb by volume, preferably less than 50 ppb by volume, more preferably less than 10 ppb by volume and an NH3 content of less than 100 ppm by volume, preferably less than 10 ppm by volume, more preferably less than 1 ppm by volume.

[0177] Preferably, step d) comprises, preferably consists of, steps d1) and / or d2) and / or d3), d4), d5) and / or d6)

[0178] Step e) of the Fischer-Tropsch synthesis catalytic reaction

[0179] The process according to the invention comprises a step e) of Fischer-Tropsch synthesis of the gaseous effluent comprising a purified synthesis gas comprising carbon monoxide (CO) and hydrogen from step d), and preferably from step d6) of final purification, and optionally of a portion of the hydrogen stream from step b) of water electrolysis so as to produce a stream comprising synthetic liquid hydrocarbons and at least one gaseous effluent.

[0180] According to the invention, at least a portion of the hydrogen from step b) of water electrolysis is advantageously recombined with the purified synthesis gas from step d) and preferably d6) to obtain an optimal H2 / CO molar ratio for the Fischer-Tropsch reaction so as to produce a stream comprising synthetic liquid hydrocarbons and at least one gaseous effluent.

[0181] According to variant A of the invention, the molar ratio between hydrogen and carbon monoxide H2 / CO at the inlet of step e) of Fischer-Tropsch synthesis is adjusted by sending into said step e) a part of the hydrogen flow from step b).

[0182] According to variant B of the invention, the molar ratio between hydrogen and carbon monoxide H2 / CO at the inlet of step e) of Fischer-Tropsch synthesis can advantageously be adjusted by sending into said step e) a part of the hydrogen flow from step b).

[0183] According to another particular embodiment of variant B of the invention, the H2 / CO molar ratio in the purified synthesis gas from step d) and preferably from d6) is adjusted to its optimal value for the Fischer-Tropsch reaction by regulating the hydrogen flow from step b) of water electrolysis which feeds step g) of CO2 conversion to hydrogen, without sending into said step e) a part of the hydrogen flow from step b).

[0184] Advantageously, step e) of the Fischer-Tropsch synthesis is carried out with a molar ratio between hydrogen and carbon monoxide, denoted H2 / CO, of between 0.5 and 4, preferably between 1 and 3, more preferably between 1.5 and 2.5 and most preferably equal to 2.1.

[0185] The gasification step c) of the feed according to the invention as implemented in the present invention can lead to the production of hydrogen and carbon monoxide in a non-optimal H2 / CO molar ratio for the Fischer-Tropsch reaction, particularly when the catalyst used is a cobalt-based catalyst which advantageously requires an optimal H2 / CO molar ratio of about 2 to be directed towards the production of middle distillates.

[0186] Said step e) of Fischer-Tropsch synthesis produces water.

[0187] Advantageously, the water formed during step e) of the Fischer-Tropsch synthesis is partly or totally sent to step b) of electrolysis. Recycling the water formed in step e) to step b) reduces the operating costs of the process according to the invention.

[0188] In one embodiment, the water formed during step e) of Fischer-Tropsch synthesis advantageously undergoes a treatment step before being recycled in step b) of water electrolysis so as to obtain the required specifications of step b). The treatment step may advantageously consist of removing oxygenated compounds from the water formed during step e).

[0189] The catalyst used in this step e) of the Fischer-Tropsch synthesis is generally any catalytic solid known to those skilled in the art that can carry out the Fischer-Tropsch synthesis. Preferably, the catalyst used in said step comprises cobalt or iron, more preferably cobalt. The catalyst used in step e) is generally a supported catalyst. The support may be, for example, based on alumina, silica, or titanium.

[0190] The temperature and pressure conditions are variable and adapted to the catalyst used in this step (e). The absolute pressure is generally between 1.0 and 6.0 MPa, preferably between 1.5 and 3.5 MPa, and preferably between 2.0 and 3.0 MPa. The temperature can generally be between 170 and 280°C, preferably between 190 and 260°C, and preferably between 210 and 240°C.

[0191] Step e) of the Fischer-Tropsch synthesis is carried out in a reaction unit comprising one or more suitable reactors, the technology of which is known to those skilled in the art. These may be, for example, multitubular fixed-bed reactors, or slurry bubble column reactors, or microchannel reactors.

[0192] According to a preferred embodiment of the invention, step e) employs one or more bubble column reactors. Since the synthesis is highly exothermic, this embodiment allows, among other things, improved thermal control of the reactor and minimal pressure drop.

[0193] According to a variant of the process of the invention, at least part of the gaseous effluent from the Fischer-Tropsch synthesis step (step e) is advantageously recycled in the gasification step c) in order to be converted into synthesis gas and thus improve the mass yield of the process chain.

[0194] In one embodiment of the invention, at least part of the gaseous effluent from step e) of Fischer-Tropsch synthesis can advantageously be sent to the combustion unit(s) of steps a) and / or f), so as to supply energy to the drying operations a1) and / or the heat treatment operations a2) and / or the hydroconversion step (f) to maximize the energy efficiency of the process chain.

[0195] In another configuration of the process according to the invention, the gaseous effluent from the Fischer-Tropsch synthesis e) is advantageously at least partly sent to an independent synthesis gas production unit (for example POx: Partial oxidation, SMR: Steam Methane Reforming, ATR: Autothermal Reforming, EHTR: Enhanced Heat Transfer Reformer), this synthesis gas can be recycled at any point in the chain.

[0196] In another configuration of the process according to the invention, the gaseous effluent from step e) of Fischer-Tropsch synthesis makes it possible to produce electricity in a combined cycle which can be partially powered by the steam produced by steps c) and e) to increase the energy efficiency of the process chain.

[0197] These different configurations can be advantageously combined in order to optimize the economy of the integrated process chain according to the invention.

[0198] f) Hydroconversion stage

[0199] According to the invention, the process of the invention comprises a step f) of hydroconversion and preferably hydrotreating and / or isomerizing at least a part and preferably all of the stream comprising liquid hydrocarbons from step e) of Fischer-Tropsch synthesis to produce at least one liquid biofuel cut and at least one gaseous effluent.

[0200] Step f) is carried out under normal operating conditions known to those skilled in the art in the presence of hydrogen and aims to valorize the liquid hydrocarbon fractions from step e) by the production of at least one liquid biofuel fraction, namely bio-naphtha, bio-gasoline, bio-kerosene, bio-diesel and very high quality bio-lubricating bases.

[0201] Said hydroconversion step f) advantageously comprises one or more combustion unit(s), preferably located upstream of the hydroconversion reactor, of said gaseous effluent produced in said step f) and / or of the gaseous effluent from step e). Said combustion unit of said step f) provides the thermal requirements of said step f) and possibly of one or more other steps of said process.

[0202] According to a preferred embodiment of the invention, said combustion unit of said step f) can be supplied with at least some of the oxygen from step b) of water electrolysis.

[0203] In another embodiment, the combustion unit of said step f) can be supplied by a flow of air optionally enriched with oxygen from step (b).

[0204] In these last two embodiments, the combustion unit advantageously includes a combustion gas cooling stage for separating carbon dioxide from water vapor by condensation. In the case of combustion using air, the combustion section is optionally supplemented by a section for separating carbon dioxide from the nitrogen contained in the said fumes, the latter may employ chemical or physical solvents or a mixture of chemical and physical solvents or any other means known to a person skilled in the art.

[0205] According to an implementation of feature B of the invention, the carbon dioxide stream produced by the combustion unit of said hydroconversion stage f) feeds the feed of stage (g), mixed with the carbon dioxide stream from stage (d) and the hydrogen stream from stage b).

[0206] More generally, all or part of the carbon dioxide stream produced by the combustion unit of the hydroconversion stage can be used as a by-product of the process that can supply a transport network, a storage unit or any carbon dioxide recovery facility external to the process.

[0207] Advantageously, the water formed in the combustion unit of step f) of hydroconversion is partly or totally sent to step b) of electrolysis. Recycling the water formed in step f) to step b) reduces the operating costs of the process according to the invention.

[0208] In one embodiment, the water formed in the combustion unit of step f) of hydroconversion advantageously undergoes a treatment step before its recycling in step b) of water electrolysis so as to obtain the required specifications of step b).

[0209] The hydrogen required for the implementation of step f) may advantageously come in whole or in part from step b) of water electrolysis.

[0210] One possible option is the production of paraffinic cuts, basic products for petrochemical processes, for example production of a C10-C13 cut intended for the production of (bio) LAB (Linear Alkyl Benzene), or of (bio) waxes for various industrial applications.

[0211] Step g) of conversion of carbon dioxide to hydrogen (RWGS)

[0212] According to the invention, the process comprises a carbon dioxide to hydrogen conversion (RWGS) step in which the feed combining at least one hydrogen stream and one carbon dioxide stream has at least one of the following two characteristics:

[0213] A / at least a portion of the hydrogen stream from step b) is mixed with the carbon dioxide stream from step (d) and optionally with a carbon dioxide stream from one or more flue gas combustion units from steps (a) and / or (e) and / or (f), and optionally with a carbon dioxide stream external to the process such that the molar ratio of hydrogen to carbon dioxide H2 / CO2 at the inlet of step g) is adjusted to between 1.8 and 3 and preferably between 1.8 and 2.5, the molar ratio H2 / CO at the inlet of step e) of Fischer-Tropsch synthesis is adjusted by another part of the hydrogen flux from step b), and / or

[0214] B / The carbon dioxide stream from step (d) is mixed with a carbon dioxide stream from one or more gaseous effluent combustion units from steps (a) (e) and / or (f), and optionally with a carbon dioxide stream external to the process, the mixture of said carbon dioxide streams and the hydrogen stream from step b) feeding the carbon dioxide to hydrogen conversion (RWGS) step (g).

[0215] Said step (g) of carbon dioxide to hydrogen conversion (RWGS) enables the conversion of a feed combining at least one hydrogen stream and one carbon dioxide stream into at least one gaseous effluent comprising carbon monoxide CO and water vapor.

[0216] In particular, the gaseous effluent produced in step g) comprises a synthesis gas enriched in CO (and depleted in hydrogen) and also comprises unconverted carbon dioxide and water vapor which is then advantageously condensed to recover water.

[0217] The gaseous effluent produced in step g) advantageously comprises a synthesis gas enriched in CO (and depleted in hydrogen) with respect to the total carbon dioxide streams from step d) and from one or more combustion units of the gaseous effluents from steps a) and / or f) (streams 12 and 20).

[0218] According to the invention, after a water cooling and condensation step, the gaseous effluent from step g) of RWGS (flow 14) is sent to step d) for the removal of acidic compounds and impurities and preferably sent to a CO2 separation unit of step d4) or combined with the syngas from step d3).

[0219] According to the invention, all or part of the hydrogen flow required for the RWGS carbon dioxide to hydrogen conversion reaction of step g) comes from the water electrolysis step of step b).

[0220] According to one or more embodiments, said step g) 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 reaction of conversion of carbon dioxide to hydrogen RWGS of step g) includes a support, for example based on alumina, silica, silica-alumina, alumina-silica.

[0221] According to one embodiment, step g) includes a heating section for the carbon dioxide streams from step d) and from one or more combustion units of the gaseous effluents from steps a) and / or f) as well as the hydrogen stream from step b) or the effluent resulting from the mixing of these streams feeding step g), said heating section enabling the temperature required for the reaction taking place in step (g) of conversion of carbon dioxide to hydrogen (RWGS) to be reached.

[0222] According to one embodiment, said step g) comprises at least one combustion unit, preferably located upstream of the carbon dioxide to hydrogen conversion reactor. Said combustion unit may advantageously be fueled at least in part by a fuel which may be a gas and preferably at least a part of the gaseous effluents from step e) and / or step f).

[0223] According to a preferred embodiment of the invention, said combustion unit of said step g) can be supplied with at least some of the oxygen from step b) of water electrolysis.

[0224] In one embodiment, the combustion unit of said step g) can be supplied by a flow of air optionally enriched with oxygen from step (b).

[0225] In these last two embodiments, the combustion unit advantageously includes a combustion gas cooling stage for separating carbon dioxide from water vapor by condensation. In the case of combustion using air, the combustion section is optionally supplemented by a process for separating carbon dioxide from nitrogen contained in the gases, this separation being carried out by the use of chemical or physical solvents, a mixture of chemical and physical solvents, or any other means known to those skilled in the art.

[0226] According to an advantageous embodiment of the invention, the carbon dioxide stream produced by the combustion unit of said step g) feeds the charge of step (g), mixed with the carbon dioxide stream from step (d) and the hydrogen stream from step b).

[0227] More generally, all or part of the carbon dioxide stream produced from step d) or produced by the combustion unit of step g) can be used as a by-product of the process to supply a transport network, a storage unit or any carbon dioxide recovery facility external to the process.

[0228] Advantageously, the water formed by the RWGS reaction, as well as that formed by the possible combustion unit of step g), is partially or totally recovered and sent to step b) of electrolysis. Recycling the water formed in step g) back to step b) reduces the operating costs of the process according to the invention.

[0229] In one embodiment, the water formed by the RWGS reaction and that formed by the possible combustion unit of step g) advantageously undergoes a treatment step before its recycling in step b) of water electrolysis so as to obtain the required specifications of step b).

[0230] According to variant A of the invention, the quantity of hydrogen from step b) at the inlet of the reaction unit of step (g) is adjusted so that the H2 / CO2 molar ratio is between 1.8 and 3 and preferably between 1.8 and 2.5. Part of the hydrogen from step b) of water electrolysis is recombined with the purified synthesis gas from step d) to obtain an H2 / CO molar ratio compatible with the need of the FT unit, i.e. preferably between 0.5 and 4, preferably between 1 and 3, more preferably between 1.5 and 2.5.

[0231] According to one embodiment, the gaseous effluent from step g) of RWGS, comprising CO, H2, unconverted CO2, and water vapor, has an outlet temperature from the reaction unit of step g) of at least 700°C, preferably at least 750°C, and most preferably at least 800°C. (See Figure for description)

[0232] The [Fig.1] illustrates the different stages of the production process according to a particular embodiment of the invention.

[0233] The feedstock is introduced into the pretreatment step (A) via the conduit 1 in which it undergoes a drying step a1), a roasting step a2) and / or a grinding step a3).

[0234] The pre-treated feed is then sent via line 2 into a gasification stage in a unit (C) mixed with oxygen 11 produced during the water electrolysis stage which takes place in the water electrolysis unit (B).

[0235] The water used in the electrolysis unit (B) comes at least in part from the Fisher-Tropsch synthesis step carried out in the unit (E) via line 9.

[0236] According to one embodiment of the invention, the water used in the electrolysis unit (B) comes at least in part from the combustion unit of the hydroconversion stage implemented in the unit (F) via the conduit 22.

[0237] According to one embodiment of the invention, the water used in the electrolysis unit (B) comes at least in part from the combustion unit of the pretreatment stage implemented in the unit (A) via the line 23.

[0238] According to one embodiment of the invention, the water used in the electrolysis unit (B) comes at least in part from the carbon dioxide hydrogen conversion step carried out in the unit (G) via the line 21.

[0239] During the water electrolysis step, a flow of hydrogen is produced and sent via pipe 13 to step (G) of RWGS.

[0240] According to one embodiment of the invention, during the water electrolysis step, a flow of hydrogen is produced and sent via the conduit 8 into the Fischer-Tropsch synthesis step (E).

[0241] The gasification step of the pretreated feedstock, which takes place in unit (C) in the presence of oxygen 11 from the water electrolysis step, produces a gaseous effluent comprising a synthesis gas. This effluent exits the gasification unit (C) via line 3 and is sent to a step d) for the removal of acidic compounds and impurities from the synthesis gas. This step may include a step d1) for water scrubbing of the synthesis gas and / or a step d2) for catalytic hydrolysis of the COS and HCN compounds and / or a step d3) for water scrubbing, and a step d4 for the separation of acidic gases. This separation step d4 is also fed by the gaseous effluent from step G) via line 14 and treated in a separate or shared separation unit with the one fed by the synthesis gas from line 3.Step d) further includes a step d5) of recombination of the gaseous effluents, either of the synthesis gas exiting unit (C) via line (3) with the gaseous effluent exiting directly from unit (G) via line 14, the flow resulting from this recombination feeding a separation unit common to step d4) or of gaseous effluents depleted in acid gases from two separate separation units in step d4). Step d finally includes a step d6) of final purification of the effluent comprising the synthesis gas from step d4) or d5).

[0242] After purification, the carbon dioxide stream from unit D feeds unit G through pipe 12.

[0243] The effluent, including the possibly purified syngas, is then sent via line 5 to a Fischer-Tropsch synthesis step which takes place in unit (E). According to one embodiment of the invention, a portion of the hydrogen stream 8 produced during the water electrolysis step is sent to unit E. A stream 6 comprising synthetic liquid hydrocarbons is produced during the Fischer-Tropsch synthesis step and is sent to a hydroconversion step in unit F which produces a stream 7 of synthetic liquid biofuels.

[0244] According to one embodiment of the invention, at least part of the gaseous effluent from unit (E) is recycled through line 17 into gasification unit C in order to be converted into synthesis gas.

[0245] According to one embodiment of the invention, part of the oxygen flow produced during the water electrolysis step is sent to one or more combustion units of unit A and / or unit F, respectively, through conduits 15 and / or 16.

[0246] According to one embodiment of the invention, the CO2 flows from one or more combustion units of unit A and / or unit F, respectively through pipes 18 and / or 19, supply unit G through pipe 20.

[0247] The examples illustrate the invention without limiting its scope. Examples

[0248] Example 1: comparative example according to the process described in WO2022 / 079407A1.

[0249] Fig. 2 shows the main flows of the process chain according to comparative example 1.

[0250] The steps implemented in the process of Comparative Example 2 are identical to those of the process according to the invention. Example 2 is comparative in that the process described in document WO 2022 / 079407 does not meet either characteristic A or characteristic B of the present invention, in that Example 2:

[0251] - does not provide for the recycling of CO2 produced by the combustion unit of stage F towards step G (19 of [Fig.2] not shown in figure 4) (characteristic B);

[0252] - In that the molar ratio between hydrogen and carbon dioxide H2 / CO2 in the reactor inlet of step g) of carbon dioxide to hydrogen conversion (R-WGS) is equal to 7.3, which is outside the range claimed in characteristic A of 1.8 to 3.

[0253] Only the CO2 12 flux produced by the deacidification step D is treated in the step G of R-WGS, i.e. a quantity of CO2 of 101 t / h.

[0254] The example takes into account a unit which processes 100 t / h of plastic feed and produces 76 t / h of hydrocarbons at the outlet of step F. The plastic feed (2) is a mixture of polymers from micronized household plastics recycled containing 25% polyethylene, 25% polypropylene, 20% polystyrene and 30% polyethylene terephthalate, this mixture containing 80% wt of carbon and 10% oxygen.

[0255] The gasification unit C, fed by the plastic feed 2 and a recycled gas stream 17 from the FT synthesis step E, produces 3 times more CO than CO2 in mol, i.e., a quantity of CO of 177 t / h. The H2 / CO ratio at the outlet of the unit is 0.5. In this example, the H2 / CO ratio is increased from 0.5 to 2.1 at the inlet of the Fischer-Tropsch synthesis step E (E) by an external hydrogen supply (not shown in the figure) produced by electrolysis of water B. The hydrogen flow rate injected at the inlet of the carbon dioxide conversion to hydrogen step RWGS (step G) is adjusted so that the H2 / CO ratio at the FT synthesis inlet is equal to 2.1 without the need for additional hydrogen supply (flow 8 of [Fig.2] equal to zero).

[0256] The quantity of hydrogen required for the R-WGS carbon dioxide conversion reaction to hydrogen is in this case 34 t / h for a CO2 flow rate of 101 t / h, i.e. a molar ratio H2 / CO2 of 7.3 at the inlet of the reactor of step G of the R-WGS carbon dioxide conversion to hydrogen. Adding a consumption of 1 t / h for the hydroconversion step, the required quantity of hydrogen is 35 t / h. To produce this quantity of hydrogen, the co-product of electrolysis, oxygen, is produced at a rate of 277 t / h. This flow rate is higher than the flow rate required for the gasification step (161 t / h).

[0257] The Fischer-Tropsch synthesis step E produces a gaseous fraction which constitutes part of the effluents from block E.

[0258] Part of this gaseous effluent can be used as fuel to provide the energy required for the R-WGS reaction (step G), in addition to the fraction used as fuel for step F. The carbon consumption corresponding to the combustion of this gaseous effluent from step E of FT synthesis for the thermal requirements of steps F and G, is estimated in this example to be 21% of the carbon contained in the plastic feed.

[0259] The overall carbon yield of the chain is therefore 79% wt, i.e. a total material yield of 76% wt.

[0260] For the production capacity of the example, the Fischer-Tropsch synthesis step E and the CO2-to-hydrogen conversion step G produce approximately 152 t / h and 39 t / h of water respectively, representing 50% of the water requirement of the electrolysis step, with a net water consumption of 188 t / h

[0261] The CO2 released by the process according to example 2 is produced mainly in two stages:

[0262] - The combustion of a portion of the gaseous effluent from unit FT for section of combustion of stage G of conversion to hydrogen of carbon dioxide R-WGS representing 54 t / h

[0263] - The combustion of a portion of the gaseous effluent from unit FT for section combustion of the hydroconversion unit at stage F representing 7.3 t / h.

[0264] The amount of oxygen required to supply energy to the gasification step C is 161 t / h, which represents 58% of the oxygen produced by electrolysis.

[0265] Fig. 2 shows the main flows of the process chain according to comparative example 1 according to prior art WO2022 / 079407A1.

[0266] Example 2 according to the invention illustrating the operation of the invention according to features A and B

[0267] The example takes into account a unit which processes 100 t / h of plastic feed and produces 85 t / h of hydrocarbons at the outlet of step F. The plastic feed (2) is a mixture of polymers from micronized household plastic recycling containing 25% polyethylene, 25% polypropylene, 20% polystyrene and 30% polyethylene terephthalate, this mixture containing 80% wt of carbon and 10% oxygen.

[0268] The example according to the invention below refers to the steps implemented in [Fig.3] according to the claimed features A and B.

[0269] In Example 2, gasification step C, fed by the plastic feedstock (2) and a recycled gaseous effluent (17) from FT synthesis step E, produces 3 times more CO than CO2 in mol, i.e., a quantity of CO of 191 t / h. As in Example 3, the H2 / CO ratio is increased from 0.5 to 2.1 at the inlet of Fischer-Tropsch synthesis step E by an external supply of hydrogen (8) produced by electrolysis. The flow rate of hydrogen injected (13) at the inlet of stage G of R-WGS is adjusted according to the implementation of the invention such that the H2 / CO2 ratio at the inlet of stage G of R-WGS is equal to 2. The implementation of the process according to feature B of the invention includes the recycling of the CO2 produced by the gaseous effluent combustion stage in stage F to stage G (flow 19) (feature B).To the CO2 flux (12) produced by step D of the removal of acidic compounds of 140t / h is added the flux 19 of 8 t / h, i.e. a total quantity of CO2 of 148 t / h treated by step G of conversion of carbon dioxide to hydrogen (RWGS). .

[0270] In this example, the quantity of hydrogen (13) injected at the carbon dioxide-to-hydrogen conversion (RWGS) stage G is 13.6 t / h for a CO2 flow rate of 148 t / h (flow 12 + 19), resulting in an H2 / CO2 molar ratio of 2 at the inlet of the R-WGS stage G reactor, according to process characteristic A. To achieve an H2 / CO2 ratio of 2.1 at the inlet of the Fischer-Tropsch reactor in stage E, an additional external hydrogen (8) produced by water electrolysis B of 23.9 t / h is mixed with the synthesis gas (5) from the acid gas removal stage D. Adding 1.2 t / h for the hydroconversion stage F, the total hydrogen requirement is 38.6 t / h. To produce such a quantity of hydrogen, the co-product of electrolysis, oxygen is produced at a rate of 306t / h.

[0271] The Fischer-Tropsch synthesis step E produces at least one gaseous effluent which constitutes part of the effluents of block E and a stream of liquid hydrocarbons (6) which is sent to the hydroconversion step F.

[0272] Part of this gaseous effluent can be used as fuel to provide the energy required for the reaction in step G of R-WGSC. Contrary to the prior art description, the energy required for step F is supplied by burning a fraction of the gaseous effluent from step E of FT synthesis with a stream of pure oxygen from electrolysis unit B, the pure CO2 emitted resulting from the combustion of the gaseous effluent from step E being recycled to step G. The carbon consumption corresponding to the loss of gaseous effluent from step E of FT synthesis is therefore limited in this example to 12% of the carbon contained in the dry feedstock, the CO2 produced by the process coming mainly from the combustion of part of the gaseous effluent from step E of FT synthesis for heat production required for step G of carbon dioxide to hydrogen conversion (RWGS) utilities representing a total of 36 t / h of CO2.

[0273] The overall carbon yield of the chain is therefore 88% wt, i.e. a total material yield of 85% wt.

[0274] The sustainable fuel production yield of the chain is therefore increased by 11% compared to the prior art process as described in Example 1.

[0275] The implementation of the process according to the invention includes recycling the water from the combustion flue gases of T (F) (stream 22) as well as the condensed water from the effluent of the RWGS reactor and the flue gases from the combustion section of stage G (stream 21). By adding these different streams with the water produced by the Fischer-Tropsch synthesis step E, approximately 228 t / h of water is recovered, representing 54% of the water requirement of the electrolysis step B.

[0276] The quantity of electrolytic oxygen required to supply energy to gasification step C, as well as for combustion in step F, is 180t / h, which represents 59% of the oxygen produced by electrolysis.

[0277] The amount of CO2 emitted into the atmosphere is 2.7 tonnes / tonne of fuel produced and the water consumption for electrolysis is 2.25 tonnes / tonne of biofuel

[0278] The CO2 emissions emitted per tonne of biofuel produced in the process according to the invention are reduced by 47% compared to the balance according to the comparative example.

[0279] The water input for electrolysis, when considered in relation to biofuel production, is reduced by 8% compared to comparative example 1.

[0280] The implementation according to the invention implementing the claimed characteristics A and B, therefore significantly improves the environmental balance of the sector compared to the prior art.

[0281] The table below summarizes the main advantages of the process according to the invention illustrated by example 2, compared with the prior art process with RWGS (example 1).

[0282] [Tables 1] Summary of results Comparative example 1 Example 2 According to prior art According to the invention Overall yield (% wt.) 79% 88% Material yield (% wt.) 76% 85% Total CO2 emissions (kg / kg product): 5.0 2.7 Electrolytic H2 consumption (kg / kg product): 0.46 0.46 Water consumption for electrolysis (kg / kg product): 2.46 2.25 Productivity gain vs. previous method: 11% CO2 reduction vs. previous method: 47% Water consumption reduction: 8%

[0283] The table above highlights in particular the gain in biogenic carbon yield and in hydrocarbon yield of said process according to the invention, either by the implementation of the CO2 to hydrogen conversion reaction optimized by the combined implementation of the two characteristics A and B according to the invention allowing a productivity gain of 11 according to example 2.

[0284] Similarly, the implementation of the invention makes it possible to reduce CO2 emissions per kg of fuel produced by 47% compared to the prior art process WO22 / 079407 by the combined implementation of the two features according to example 2.

[0285] Finally, the implementation of the invention makes it possible to reduce the water consumption for the electrolysis step B per kg of fuel produced by 8% compared to the prior art process WO22 / 079407 in Example 2.

[0286] In conclusion, the results of the various examples illustrate the advantages of the invention for significantly improving productivity, the environmental balance and limiting the operating costs of the process.

Claims

1. Demands A process for converting a feedstock comprising at least a carbonaceous plastic fraction and producing carbon dioxide into hydrocarbons, said process comprising at least the following steps: - optionally a pretreatment step of the feedstock, - a step of electrolysis of water into oxygen and hydrogen allowing the production of a hydrogen stream and an oxygen stream, in which the water is obtained, at least in part, from a Fischer-Tropsch synthesis step. - a step c) of gasification of the feed possibly pre-treated in step a), in the presence of all or part of the oxygen flow from step b) of water electrolysis so as to obtain a gaseous effluent comprising a synthesis gas, - a step d) of removing acidic compounds and impurities from the gaseous effluent comprising a synthesis gas from step c) mixed with a gaseous effluent from step g) after condensation of water vapor, so as to obtain a gaseous effluent comprising a purified synthesis gas and a carbon dioxide stream feeding at least in part a step (g) of conversion of carbon dioxide to hydrogen (RWGS), - a Fischer-Tropsch synthesis step e) of the gaseous effluent comprising a purified synthesis gas from step d) and possibly part of the hydrogen stream from step b) of water electrolysis so as to produce a stream comprising synthetic liquid hydrocarbons, water and at least one gaseous effluent, - a step (f) of hydroconversion of at least a portion of the stream comprising liquid hydrocarbons from step (e) to produce at least one liquid biofuel cut and at least one gaseous effluent - a carbon dioxide to hydrogen conversion step (g) to produce at least one gaseous effluent comprising carbon monoxide CO and water vapor, wherein the feed entering said step g) comprising at least a portion of the hydrogen stream from step b) and a carbon dioxide stream, has at least one of the following two characteristics: A / at least part of the hydrogen stream from step b) is mixed with the carbon dioxide stream from step (d) and possibly with a carbon dioxide stream from one or more combustion units of the gaseous effluents from steps e) and / or f) and / or possibly a), and possibly with a carbon dioxide stream external to the process, such that the molar ratio between hydrogen and carbon dioxide H2 / CO2 at the inlet of the reactor in step g) of carbon dioxide to hydrogen conversion is adjusted between 1.8 and 3, the molar ratio between hydrogen and carbon monoxide H2 / CO2 at the inlet of step e) of Fischer-Tropsch synthesis is adjusted by another part of the hydrogen stream from step b),and / or B / The carbon dioxide stream from step (d) is mixed with the hydrogen stream from step b) and a carbon dioxide stream from one or more combustion units of the gaseous effluents from steps e) and / or f) and / or possibly a), and possibly with a carbon dioxide stream external to the process, the mixture of said carbon dioxide streams and the hydrogen stream from step b) feeding the carbon dioxide to hydrogen conversion (RWGS) step (g).

2. A process according to claim 1 wherein said carbon plastic fraction comprises one or more polymers selected from thermoplastic polymers, thermosetting polymers, elastomers, alone or in mixtures.

3. A process according to claim 2 wherein said carbonaceous plastic fraction is derived from the recycling of solid municipal waste, industrial polymers or household plastics and is a mixture of solid or liquid fillers.

4. A process according to any one of claims 1 to 3, wherein said carbonaceous plastic fraction further comprises a fraction of another gaseous, solid and / or liquid hydrocarbon feedstock selected from a feedstock that may contain at least coal, petroleum coke, natural gas, petroleum residues, crude oils, topped-off crude oils, deasphalted oils, deasphalting asphalts, petroleum conversion process derivatives, oil sands or their derivatives, shale gas and oil shale or their derivatives, liquid biomass, biomass in slurry according to Anglo-Saxon terminology corresponding to a mixture of liquid biomass with a solid hydrocarbon feedstock.

5. A process according to any one of claims 1 to 4 wherein said pretreatment step a) comprises one or more gas combustion unit(s) and preferably pretreatment gas, produced in said step a) and preferably in a heat treatment operation a2), wherein said gas is burned in a combustion step to produce combustion fumes containing carbon dioxide.

6. A method according to claim 5 wherein the combustion unit(s) of said pretreatment step a) are supplied with at least some of the oxygen from the water electrolysis step b) or with an air stream optionally enriched with oxygen from the step (b).

7. A method according to any one of the preceding claims wherein said hydroconversion step f) comprises one or more combustion unit(s), preferably located upstream of the hydroconversion reactor, of said gaseous effluent produced in said step f) and / or of the gaseous effluent from step e), supplied by at least a portion of the oxygen from water electrolysis step b) or by an air stream optionally enriched with oxygen from step (b).

8. A method according to claim 7 wherein the combustion unit(s) include a combustion flue gas cooling step enabling the separation of carbon dioxide from water vapor by condensation.

9. A method according to any one of the preceding claims wherein said step g) comprises at least one combustion unit, preferably located upstream of the carbon dioxide to hydrogen conversion reactor, supplied at least in part by a fuel being a gas and preferably at least a part of the gaseous effluents from step e) and / or step f) and by at least a part of the oxygen from step b) of water electrolysis or by an air stream possibly enriched with oxygen from step (b).

10. A method according to claim 9 wherein the combustion unit(s) of said stage g) comprise a combustion flue gas cooling stage enabling the separation of carbon dioxide from water vapor by condensation and the resulting carbon dioxide stream feeds the charge of stage (g).

11. A process according to any one of claims 2 to 10 wherein the water produced in any one of the process steps, and preferably the water produced in the combustion unit(s) of the wet feed pretreatment step a) and / or the hydroconversion step f), preferably by condensation of the combustion fumes from said combustion units, the water produced in the Fischer-Tropsch synthesis step e), and the water produced in the carbon dioxide to hydrogen conversion (RWGS) step g), is recycled in the water electrolysis step b).

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