Electricity generation facility comprising a thermal power plant, in particular a nuclear power plant, with a system for converting thermal energy into electrical energy (ecs system), and at least one exothermic chemical production unit of which at least part of the high-temperature and / or low-temperature waste heat is reinjected into the ecs system of the facility

Abstract

The invention essentially consists in producing at least one closed loop provided with a heat exchanger in order to achieve indirect thermal coupling by returning at least high-temperature and / or low-temperature waste heat from a production unit (500) for producing at least one synthetic fuel to a thermal power plant (1), wherein the thermal power plant (1) is provided with a system (10) for converting heat into electricity, and wherein the hydrogen required for the production unit is supplied by a hydrogen-production unit (300) that produces hydrogen by electrolysis and is itself thermally coupled to the thermal power plant.

Description

[0001] Description

[0002] Title: Electricity generation installation comprising a thermal power plant, in particular nuclear, with a thermal energy-to-electrical energy conversion system (CES), and at least one exothermic chemical production unit of which at least part of the high-temperature and / or low-temperature waste heat is reinjected into the installation's CES system.

[0003] technical field

[0004] The present invention relates to the field of electricity generation installations from a thermal power plant.

[0005] For the purposes of this invention, "thermal power plant" means any power plant that generates heat for the production of electricity and that operates from a heat source according to the principle of heat engines and that includes a system for converting thermal energy from the heat source into electricity (SCE).

[0006] A thermal power plant conforming to the invention may be:

[0007] - a nuclear power plant including a steam turbine;

[0008] - a power plant recovering pre-existing heat (solar thermodynamic, geothermal steam, etc.) including a steam turbine,

[0009] - a power plant with at least one salt reservoir heated by an electrical resistance, including a steam turbine;

[0010] - a power plant or any other decarbonized heat source whose characteristics, particularly temperature, allow conversion into electricity.

[0011] A nuclear power plant suitable for the purposes of the invention may consist of one or more light water reactors (LWRs), in particular pressurized water reactors (PWRs) with conversion cycle inlet temperatures of approximately 300 °C, or boiling water reactors (BWRs), or one or more fourth-generation reactors (GEN IV), in particular small modular reactors (SMRs) or advanced nuclear reactors (AMRs), with conversion cycle inlet temperatures exceeding 500 °C. These may be liquid metal-cooled fast neutron reactors, in particular liquid sodium-cooled reactors known as SFRs (sodium fast reactors), which belong to the GEN IV reactor family.

[0012] The installation according to the invention can be a cogeneration installation, i.e. the simultaneous or non-simultaneous production of electricity and heat.

[0013] Hydrogen production within the framework of the invention can be achieved by high-temperature water electrolysis (HTE, or EVHT for high-temperature steam electrolysis, or HTE, English acronym for "High Temperature Electrolysis", or HTSE, English acronym for "High Temperature Steam Electrolysis") also with solid oxides (SOEC, English acronym for "Solid Oxide Electrolysis Cell"), or by alkaline electrolysis or by proton-exchange membrane electrolysis (PEM for "Proton-Exchange Membrane") or by anion-exchange membrane electrolysis (AEM for "Anion-Exchange Membrane").

[0014] The production of at least one synthetic fuel by exothermic chemical reaction can be achieved through a reverse water-gas shift (RWGS) process and / or a Fischer-Tropsch (FT) process, and where appropriate, by a reforming process to produce a synthetic fuel such as kerosene, methane, or to produce methanol, ammonia, etc. Reforming allows for the recycling of fractions including carbon chains below C5 to maximize the production of the fraction of interest. Kerosene containing CS-ClO carbon chains is typically obtained after distillation at atmospheric pressure.

[0015] Although described with reference to a pressurized water nuclear reactor power plant, the invention applies to any other thermal power plant as previously mentioned comprising a thermal energy-to-electricity (TEE) conversion cycle, in particular a Rankine cycle.

[0016] Previous technique

[0017] In the context of climate and energy transition, the nuclear industry must meet several challenges for the future. Indeed, to address tomorrow's energy and societal challenges, it will be essential to design nuclear reactors that enable:

[0018] - to limit the need for so-called "environmental" liquid cold sources (rivers, streams, sea) and the associated discharges into the environment; - to be more flexible and therefore more complementary to other so-called renewable energies (RE), to meet the fluctuating demand for electricity and the intermittency of RE;

[0019] - to decarbonize processes by supplying heat to consuming industries (desalination, heat networks, hydrogen...) while increasing energy efficiency;

[0020] - to capture atmospheric CO2 to limit the effects of global warming and contribute to closing the carbon cycle as a source of carbon for industrial processes; and this, without degrading the profitability of the installation, either by economically benefiting from the new services provided, or by significantly increasing the amount of electricity produced during the day.

[0021] Recently, numerous studies have highlighted the possibility of combining nuclear power reactors with hydrogen production units from high-temperature water electrolysis, in order to create cogeneration plants that efficiently produce electricity and hydrogen: [1], [2].

[0022] Water electrolysis is an electrochemical reaction that decomposes water into dioxygen and dihydrogen gases with the help of an electric current, according to the reaction:

[0023] H2O — ► H2+ 1 / 2 O2.

[0024] To carry out the electrolysis of water, it is advantageous to carry it out at high temperature typically between 600 and 950°C, because part of the energy required for the reaction can be supplied by heat, which is cheaper than electricity, and carrying out the reaction is more efficient at high temperature and finally it may not require a catalyst.

[0025] To implement high-temperature electrolysis, a reactor, also called a SOEC (Solid Oxide Electrolysis Cell), is commonly used. This reactor consists of a stack of elementary units, each containing a solid oxide electrolysis cell. The cell comprises three layers: anode, electrolyte, and cathode, stacked one on top of the other. Interconnecting plates, for example, made of metallic alloys, are also called bipolar plates or interconnectors. The interconnectors ensure both the passage of electric current and the circulation of gases in the vicinity of each cell (injected steam, hydrogen and oxygen extracted in an EHT electrolyzer). They also separate the anodic and cathodic compartments, which are the gas circulation compartments on the anode and cathode sides of the cells, respectively.To perform high-temperature steam electrolysis (HTE), water vapor (H₂O) is injected into the cathode compartment. Under the influence of the current applied to the cell, the dissociation of water molecules into vapor occurs at the interface between the hydrogen electrode (cathode) and the electrolyte: this dissociation produces hydrogen gas (H₂) and hydroxide ions (OH⁻). The hydrogen gas is collected and discharged from the hydrogen compartment. The hydroxide ions (OH⁻) migrate through the electrolyte and recombine into oxygen at the interface between the electrolyte and the oxygen electrode (anode).

[0026] To increase the flow rates of hydrogen and oxygen produced, it is known to stack several elementary electrolysis cells on top of each other, separated by interconnecting devices, usually called interconnectors or bipolar interconnecting plates. The assembly is positioned between two end interconnecting plates that support the electrical and gas supplies for the electrolyzer (electrolysis reactor).

[0027] A high-temperature water electrolyzer (HTW) thus comprises at least one, usually a plurality of electrolysis cells stacked on top of each other, each elementary cell being formed of an electrolyte, a cathode and an anode, the electrolyte being intercalated between the anode and the cathode.

[0028] In steady-state operation, a high-temperature electrolyzer (HTE) requires upstream combined thermal and electrical power to bring the reactants to the temperature required for electrolysis, and within itself an electrical power input to carry out the electrolysis.

[0029] The applicant proposed in the patent application filed on December 21, 2022 under number FR2214108 and entitled "Light Water Reactor (LWR) Nuclear Cogeneration Plant and High Temperature Water Electrolysis System(s) for Hydrogen Production from Heat of LWR Reactor", an optimal indirect thermal coupling, i.e. without any mass transfer, between a nuclear reactor and a high temperature electrolysis hydrogen production unit by means of a judiciously chosen withdrawal tap downstream of the high pressure body of the Rankine cycle turbine of the nuclear reactor which will transfer the heat thus withdrawn, via a closed loop between an intermediate heat exchanger and a coupling steam generator, to liquid water supplying the production unit in order to inject steam at a high temperature required to carry out the electrolysis.This indirect heat input can be continuous or gradually reduced until the heat released by the electrolysis reaction is sufficient to power it. This application also includes a heat reinjection coupling circuit in the reactor's tertiary circuit, which allows for the recovery of at least some of the waste heat—that is, the heat recovered from the electrolysis outlet gas cooling system that was not used in the electrolysis process. The reinjected waste heat can be considered to be in a low-temperature range, typically between 80°C and 150°C.

[0030] The inventors were interested in the possibility of creating an integrated energy installation with a nuclear reactor and a synthetic fuel production chain, including kerosene.

[0031] Synthetic fuels can be obtained through thermochemical processes, via different conversion pathways, from energy carriers such as heat and electricity and raw materials such as water and CO2.

[0032] US20130281553A1 describes the production of synthetic fuels coupled with a dedicated nuclear reactor in which carbon dioxide and hydrogen are combined to produce synthetic gas, which is then converted into the product of interest. The hydrogen and carbon dioxide are obtained through electrolysis and carbon capture processes, respectively. The fuels can be produced, in particular, by the Fischer-Tropsch process. The described coupling demonstrates the advantages of integrating a chemical production plant with a nuclear reactor to provide the electrical and thermal energy required for the various processes. Furthermore, this patent application suggests the possibility of using the absorbent solution employed for carbon dioxide capture to cool the nuclear reactor.

[0033] Other publications mention more specifically the coupling between a nuclear reactor and a synthetic fuel production process.

[0034] Publication [3] thus reveals the possibility of using steam generated by a light water reactor (LWR) in an electrolysis unit and in post-treatment units such as distillation and hydrotreating. Publication [4] also mentions the supply by a nuclear reactor of steam and electricity necessary for a high-temperature electrolysis unit as well as the electricity required for the various units of a synthetic fuel production system.

[0035] All these coupling solutions between a nuclear reactor, a high-temperature electrolysis unit whose necessary electricity is supplied by the nuclear reactor and at least one synthetic fuel production unit from the hydrogen produced by the electrolysis unit are not optimal, in terms of energy efficiency.

[0036] There is therefore a need to improve the installations for generating electricity by nuclear reactor(s) and for the simultaneous or non-simultaneous production of a synthetic fuel from the heat supplied by the nuclear reactor(s) and the hydrogen supplied by an electrolysis unit of the installation, by improving their energy efficiency.

[0037] More generally, there is a need to improve the energy efficiency of an installation comprising a thermal power plant, a thermal energy to electrical energy conversion system (TEE), at least one electrolysis unit whose required electricity is supplied by the TEE system and at least one chemical production unit for at least one synthetic fuel whose required heat is supplied by the thermal power plant and the required hydrogen is supplied by the electrolysis unit.

[0038] The aim of the invention is to meet at least partially this need(s).

[0039] Description of the invention

[0040] To this end, the invention relates, in one of its aspects, to an electricity generation installation, intended to produce electricity and, where applicable, heat, comprising:

[0041] - a thermal power plant, with a thermal energy conversion system (CES);

[0042] - at least one electrolysis unit, electrically connected to the SCE system and capable of being thermally coupled to the thermal power plant by a fluidic circuit, so as to be supplied respectively with the electricity and heat required for the electrolysis reaction;

[0043] - at least one production unit for at least one synthetic fuel or organic chemical compound, adapted to carry out at least one exothermic synthesis reaction; the production unit being connected to the electrolysis unit by a fluidic circuit and so as to be supplied with hydrogen; - at least one fluidic circuit, called a high-temperature and / or low-temperature reinjection coupling circuit, to thermally couple the output of the production unit to at least a part of the SCE system so as to reinject at least a part of the so-called high-temperature and / or low-temperature waste heat produced by the exothermic synthesis reaction into the SCE system.

[0044] The heat transfer fluid of the high-temperature reinjection coupling circuit is preferably at a temperature of at least 150°C, advantageously between 200 and 300°C, advantageously between 215 and 275°C.

[0045] The heat transfer fluid of the low-temperature reinjection coupling circuit is preferably at a temperature of at least 80°C, advantageously between 80 and 150°C, advantageously between 80 and 100°C.

[0046] According to an advantageous embodiment,

[0047] - The SCE system implements a Rankine cycle comprising:

[0048] • at least one steam generator,

[0049] • at least one turbine comprising a high-pressure casing connected to the steam generator and a low-pressure casing connected to the high-pressure casing by at least one fluidic branch,

[0050] • a high-pressure heater connected to the high-pressure body, to a water tank (called a feed tank), and to the steam generator,

[0051] • a low-pressure heater connected on one side by at least one fluid branch to the low-pressure body and on the other side by at least one fluid branch to the feed tank,

[0052] • a condenser, connected on one side to the low-pressure body and on the other side to the low-pressure heater;

[0053] - The high-temperature reinjection coupling circuit includes:

[0054] • a heat exchanger connected on one side in a closed loop to the outlet of the production unit of at least one synthetic fuel and on the other side at the inlet to the high-pressure body and at the outlet to the low-pressure body, and / or • a heat exchanger connected on one side in a closed loop to the outlet of the production unit of at least one synthetic fuel and on the other side at the inlet upstream of the high-pressure heater and at the outlet to the steam generator, and / or

[0055] • a heat exchanger connected on one side in a closed loop to the outlet of the production unit of at least one synthetic fuel and on the other side at the inlet to the high-pressure body and at the outlet to the high-pressure heater, and / or

[0056] • a heat exchanger connected on one side in a closed loop to the outlet of the production unit of at least one synthetic fuel and on the other side at the inlet to the low-pressure body and at the outlet to the low-pressure heater, and / or

[0057] • a heat exchanger connected on one side in a closed loop to the outlet of the cooler and on the other side at the inlet between the condenser and the low pressure heater and at the outlet between the low pressure heater and the food storage tank.

[0058] According to another embodiment, the installation further comprises at least one direct carbon dioxide capture (DAC) unit, connected to the production unit of at least one synthetic fuel by a fluidic circuit and thermally coupled to the thermal power plant by a fluidic circuit so as to respectively supply the production unit with CO2 necessary for the exothermic synthesis reaction and to be supplied with heat necessary for the direct capture of CO2.

[0059] According to another embodiment, the installation further includes, at the outlet of the cooler, a low-temperature preheater for the electrolysis unit and, where applicable, a low-temperature preheater for the direct carbon dioxide capture (DAC) unit.

[0060] Advantageously, the synthetic fuel production unit is adapted to implement a reverse water gas shift (RWGS) process and / or a Fischer-Tropsch (FT) process and, where appropriate, a reforming process.

[0061] Advantageously, the SCE system implements a Rankine cycle including an alternator adapted to supply at least part of its electricity to the electrolysis unit and, where applicable, to the direct carbon dioxide capture (DAC) unit. The electrolysis unit is preferably a high-temperature electrolysis unit.

[0062] The invention essentially consists of making at least one closed loop with heat exchanger to achieve indirect thermal coupling by return of waste heat at least at high temperature and / or at low temperature, to a thermal power plant with its heat-to-electricity conversion system, of a production unit of at least one synthetic fuel whose necessary hydrogen is supplied by a hydrogen production unit by electrolysis itself thermally coupled with the thermal power plant.

[0063] By "indirect" we mean here and within the framework of the invention the fact that there is no mass transfer between the cycles of the thermal power plant and the production unit of at least one synthetic fuel, and therefore that the heat transfer takes place through heat exchangers.

[0064] In other words, according to the invention, the high-temperature and / or low-temperature thermal discharges from the production unit of at least one synthetic fuel are at least partially reinjected into the SCE system of the thermal power plant.

[0065] Ultimately, indirect thermal coupling with reinjection of waste heat from the production unit of at least one synthetic fuel offers a number of advantages, including:

[0066] - an overall energy efficiency of the combined electricity, heat and synthetic fuel installation (where applicable) produced from hydrogen by high-temperature electrolysis that is greater than or at least equal to existing solutions,

[0067] - the safety of a thermal power plant, in particular an unmodified nuclear reactor,

[0068] - the absence of risk to the overall installation,

[0069] - operating conditions of the nuclear reactor, the hydrogen production unit and the synthetic fuel production unit which can remain the same and independent of each other;

[0070] - the possibility of producing synthetic fuels or electrofuels, known as "e-fuels," independently of an electrical grid. Other advantages and features of the invention will become clearer upon reading the detailed description of illustrative and non-limiting examples of implementation of the invention, with reference to the following figures.

[0071] Brief description of the drawings

[0072] [Fig 1] Figure 1 is a schematic view of a cogeneration plant according to the invention of a pressurized water reactor (PWR) thermally coupled with a high temperature electrolysis unit and a synthetic fuel production unit whose waste heat is reinjected into the conversion system (CS) of the nuclear power plant, Figure 1 showing the thermal couplings on the CS system side.

[0073] [Fig 2] Figure 2 is a schematic view illustrating the EHT electrolysis, direct CO2 capture and synthetic fuel production units of the installation according to Figure 1, Figure 1 showing the thermal couplings on the unit side.

[0074] [Fig 3] Figure 3 illustrates two nuclear installation configurations according to the state of the art and two configurations of a nuclear installation according to the invention, as illustrated in Figures 1 and 2.

[0075] [Fig 4] Figure 4 shows, in the form of a bar chart, the energy efficiencies of the different configurations of Figure 3, calculated from a nuclear reactor with a power output of 100 MW.

[0076] Detailed description

[0077] Throughout this application, the terms "inlet", "outlet", "upstream", "downstream" are to be understood by reference to the direction of flow of a heat transfer fluid within one of the fluidic circuits, symbolized by an arrow, of an installation according to the invention.

[0078] Points A to P of the different fluidic lines concerned in Figure 1 are symbolized by circles.

[0079] Figures 1 to 2 show a nuclear installation with a PWR reactor according to the invention.

[0080] The primary circuit 1 is a closed-loop fluidic circuit comprising mainly the reactor core 2, a heat exchanger 3 as a steam generator (SG), and a hydraulic pump 4 to circulate the heat transfer fluid which is water which changes from the liquid state to the vapor state, typically around 300°C at high pressure, typically around 150 bar, in normal operation.

[0081] Other equipment, such as a pressurizer and all the devices that ensure operation under the required safety conditions, is not described here.

[0082] The secondary circuit 10 is a thermal energy to electrical energy conversion system (TEE) which mainly comprises a turbine 6 consisting of a high pressure body 60 and a low pressure body 61 connected to the high pressure body 60 by a fluid branch 62, a condenser 7 connected to the low pressure body 61 by a fluid branch 63 and a hydraulic pump 80 to circulate water in liquid form as a heat transfer fluid.

[0083] Thus, in this circuit 10, the water in the form of steam is expanded in the high-pressure body of the turbine, then superheated before continuing its expansion in the low-pressure body 61. The turbine drives an alternator 9 which produces electricity.

[0084] The water from the secondary circuit is then condensed via condenser 7, as a so-called "cold" source.

[0085] The steam generator 3 produces steam for the high and low pressure bodies 60, 61 of the turbine 6, which is characteristic of a Rankine cycle with the operating modalities of a generator cycle of the installation and must be able to operate according to the needs of an electrical network.

[0086] Steam generator 3 is typically sized to remove 1.5 times the power of the nuclear reactor. It should be noted that the turbine housings 60 and 61 are sized based on the peak steam flow rate produced by steam generator 30.

[0087] The hydraulic pump 4 is designed to operate at least at the availability coefficient Kd of the nuclear reactor and must be able to operate according to the fluctuations in the electricity requirements of the electrical network to which the alternator 9 of the nuclear reactor is electrically connected.

[0088] The flow rate of pump 4 must, taking into account the heat capacity of the heat transfer fluid and the sizing of the steam generator 3, supply the latter with heat transfer fluid at a rate sufficient to meet the power demands of the electrical grid. Pump 4 has metal walls resistant to the chemical attack of the heat transfer fluid at high temperatures, typically above 300°C. Several pumps can be positioned in parallel to distribute the pumping flow rate, and a redundant pump can be provided for safety reasons.

[0089] The circuit 10 also includes at least one circuit for heating the feedwater of the steam generator 3 before it is injected / expanded as steam into the high-pressure body 60 of the turbine 6.

[0090] This heating circuit includes firstly a high-pressure heater 64 connected to the high-pressure body 60, to a water tank, called a feed tank 66, and to the first steam generator 30. It also includes a low-pressure heater 65 connected on the one hand by at least one fluid branch to the low-pressure body and on the other hand by at least one fluid branch to the condenser 7.

[0091] In this circuit, a condensate extraction pump 81 from the condenser 7 conveys it to the feed tank 66 via the low pressure heater 65. The condensate is typically at a temperature of 40°C at a pressure of around 0.075 bar at the outlet of the condenser 7.

[0092] As shown in Figure 1, the low-pressure heater 65 uses as a heat source the steam drawn from the low-pressure body 61 of the turbine 6. The low-pressure heater 65 thus heats the feedwater of the steam generator 30. When the feedwater leaves the low-pressure heater 65, it typically has a temperature between 80 and 100 °C.

[0093] Pump 80 brings this feed water from the feed tank 66 to the high-pressure heater 64 to bring it to a temperature of around 150°C at a pressure of 40 bars in the steam generator 30.

[0094] A steam dryer 67 is arranged between the high-pressure bodies 60 and low-pressure bodies 61 of the turbine 6 and is connected to the feed tank.

[0095] The high-pressure heater 64 uses as a heat source the steam drawn from the high-pressure body 60 of the turbine 6. The installation according to the invention further comprises at least one high-temperature electrolysis unit EHT 100 thermally coupled to the nuclear reactor by an injection coupling circuit 200.

[0096] This injection coupling circuit 200 includes first of all an intermediate heat exchanger 202 connected in a closed loop to a withdrawal tap A, made in the fluid branch 62 between the high pressure body 60 and the low pressure body 61 of the turbine, and to the feed tank 66. More precisely, taking into account the temperature and pressure of the hot steam that we wish to withdraw, the withdrawal tap A is at a point in the branch 62 which connects the high pressure body 60 of the turbine and the dryer 67.

[0097] As detailed later, this tapping at point A is chosen at the appropriate temperature level to provide the latent heat necessary to vaporize the feed water in unit 100.

[0098] The tapping of the A supply can be carried out in a strictly identical manner (type of weld, characteristic diameter of pipe, etc.) to that of the tapping supplying the high pressure heater 64.

[0099] Branch A is advantageously equipped with a regulating valve for the inlet pressure in the intermediate heat exchanger 202. This regulating valve can also be used as an inlet pressure regulating valve in the high-pressure heater 64. This allows the valve to be operated in two different modes. This regulating valve optimizes the operation and control of the coupling cycle 200, offering a high degree of flexibility.

[0100] In the closed loop from the draw-off point A, the fluid branch 201 allows the steam to be channeled and transferred to the exchanger 202. After heat exchange, the fluid branch 203 returns the liquid water to a point B of the feed tank.

[0101] This circuit also includes a second steam generator, called the coupling steam generator 205, adapted to produce feed steam at an inlet point C of the electrolysis unit 100 from demineralized liquid water coming from a point D. This coupling generator 205 is also connected in an intermediate closed loop to the heat exchanger 202. In this intermediate closed loop 207, a circulation pump 206 brings pressurized liquid water via the fluid branch 204 from the exchanger 202 to the coupling generator 205 and then, after heat exchange, returns the water via the fluid branch 207 to the exchanger 202.

[0102] The installation according to the invention further comprises, at least one 300 unit of direct air capture (DAC for "Direct Air capture"), thermally coupled to the nuclear reactor by an injection coupling circuit 400.

[0103] This circuit 400 includes first of all an intermediate heat exchanger 402 connected in a closed loop to a first injection spigot made at point E at the level of the body of the low pressure turbine 61, and to a second reinjection spigot made at point F between the outlet of the body of the low pressure turbine 61 and the condenser 7.

[0104] In this closed loop from the draw-off point E, the fluid branch 401 brings a mixture of water and steam to the exchanger 402 and after exchange, the fluid branch 403 allows the pressurized liquid water to be channeled and transferred to point F.

[0105] This circuit also includes an intermediate heat exchanger 405, called a coupling exchanger, connected to a fluidic branch 408 whose inlet at the withdrawal point G is connected to a supply of desorbed CO2 from unit 300 (DAC) and the outlet is connected to at least one supply of absorbed CO2 from unit 300 (DAC).

[0106] This coupling exchanger 405 is connected in an intermediate closed loop to the heat exchanger 402, so as to inject the heat required for the operation of unit 300 (DAC).

[0107] In this intermediate closed loop, a circulation pump 406 brings a heat transfer fluid from the coupling exchanger 402 via a fluid branch 404 to the exchanger 405 and then after heat exchange, returns the heat transfer fluid via a fluid branch 407 to the exchanger 402.

[0108] The installation also includes a synthetic fuel production unit that can implement a reverse water-gas shift (RWGS) process and / or a Fischer-Tropsch (FT) process, and, if necessary, a reforming process. The latter allows for the recycling of fractions including carbon chains below C5 to maximize the production of the fraction of interest. The fraction of interest is kerosene, comprising Cs-Ci6 chains and typically obtained after atmospheric pressure distillation.

[0109] As illustrated in Figure 2, the production unit 500 is supplied directly with hydrogen produced by the high-temperature electrolysis unit 100 and with carbon dioxide CO2 captured by the DAC unit 300.

[0110] The synthetic fuel exiting production unit 500 undergoes two consecutive coolings (Cooling 1, Cooling 2) and, if necessary, a third cooling before being discharged.

[0111] In the installation according to the invention, the waste heat generated by the production unit 500 is reinjected into the Rankine cycle 10.

[0112] A first reinjection coupling circuit 600 of the low-temperature waste heat, typically in a range of 80°C to 150°C, includes firstly a coupling heat exchanger 602 connected in a closed loop by a fluid branch 601 to a first sampling tap made at point I between the condenser 7 and the low-pressure heater 65, preferably downstream of the low-pressure pump 81, and by a fluid branch 603 to a second reinjection tap made at point J at the outlet of the low-pressure heater 65, upstream of the feed tank 66.

[0113] In this closed loop, pressurized liquid water is brought to the exchanger 602 and after exchange, the fluid branch 603 allows the heated pressurized liquid water to be channeled and transferred to point J.

[0114] The coupling exchanger 602 is also connected to a closed loop 604. In this closed loop 604, the pressurized liquid water is heated by Cooling 2 at the outlet of the exchanger 602 at point L and returns to the exchanger at point K with the heated water which has therefore recovered the low-temperature waste heat from the production unit 500.

[0115] Also, as shown in Figure 2, the liquid water heated at Cooling 2 can serve as a preheating liquid for the water and carbon dioxide feeding the electrolysis unit EHT 100. A second high-temperature waste heat reinjection coupling circuit 700, typically in a range of 200°C to 350°C, includes firstly a coupling heat exchanger 702 directly connected to a fluid branch 701 between the dryer 67 and the body of the low-pressure turbine 61.

[0116] In this fluid branch 701, the pressurized liquid water at point M is brought from the dryer 67 to the exchanger 702 and after exchange, the liquid water heated at point N is channeled and transferred to the low-pressure turbine body 61.

[0117] The coupling exchanger 702 is also connected to a closed loop 703. In this closed loop 703, a heat transfer fluid which has recovered the high-temperature waste heat from the outlet of the production unit 500 supplies the exchanger 702 at point O and supplies the production unit back from point P.

[0118] The second reinjection coupling circuit 700 may include another coupling heat exchanger 704 connected in a closed loop by a fluid branch 705 to a first sampling tap made at point M' at the inlet of the high-pressure heater, and by a fluid branch 706 to a second reinjection tap made at point N' at the inlet of the steam generator 3.

[0119] In this closed loop, the pressurized steam is brought to the exchanger 704 and after exchange, the fluid branch 706 allows this heated pressurized steam to be channeled and transferred to point N'.

[0120] The coupling exchanger 704 is also connected to the closed loop 703 or a closed series or parallel fluid loop. In this closed loop, a heat transfer fluid that has recovered the high-temperature waste heat from the outlet of the production unit 500 supplies the exchanger 704 at point O' and returns to the production unit from point P'.

[0121] Point O and point O' can be the same, and points P and P' can be the same. In the illustrated example, heat exchangers 702 and 704 are in fluidic parallel.

[0122] In the illustrated example, each fluid branch of the circuits consists of a cylindrical pipe, preferably with metallic walls, insulated externally with high-temperature insulation. The diameter of each pipe is calculated to allow the dissipation of all the thermal power with a maximum permissible flow velocity of the heat transfer fluid, typically on the order of 1 to 10 m / s. The electrical network connected to the alternator 9 is designed to transport and distribute electricity to end users according to their needs. This electrical network is adapted to the voltage requirements of the systems and operates according to the power demands related to electricity use; it must be able to accept the peak electrical power produced by the installation.

[0123] In addition, alternator 9 can supply the electricity requirements of the EHT 100 unit, including the electrolyzers which require direct current to implement high-temperature electrolysis, the DAC 300 unit and all the electrical requirements of the other systems.

[0124] The inventors have performed a sizing of all the components of the cogeneration plant, characterizing each point of the 200, 400, 600, and 700 circuits in terms of temperature and pressure. This sizing was established using software, known as CYCLOP, which the applicant has qualified for the steady-state sizing of thermodynamic conversion cycles.

[0125] The CYCLOP software essentially allows the modeling of an energy conversion cycle, consisting of different loops connected by thermal, mechanical, or electrical exchanges. Each loop is made up of components (heat exchangers, pumps, turbines, etc.) linked to each other by fluid circulation.

[0126] This software calculates each thermodynamic point of the complete cycle and deduces the useful energy production and therefore its efficiency. Each component is characterized by selected macroscopic quantities, but this tool can be linked to more detailed pre-sizing modules to obtain more precise characteristics of a given cycle.

[0127] The software also allows the optimization of the efficiency of a cycle according to its free parameters (turbine pressure ratio, withdrawal pressures and flow rates, etc.), using deterministic or genetic optimization algorithms.

[0128] The use and relevance of this software are described, for example, in [5] or [6]. Sizing can also be performed using other commercial software, notably THERMOELEX®. The energy efficiency of the installation is calculated for a 100 MW nuclear reactor; it corresponds to the lower heating value of a liquid cut (C5+) from a production unit divided by the core power of the nuclear reactor.

[0129] Table 1 below gives different values ​​of water temperature and pressure at the various points A to P mentioned above as well as in the different fluid branches concerned of circuits 200, 400, 600, 700 were obtained using the CYCLOP software.

[0130] [Table 1]

[0131] The inventors calculated the energy efficiency of one configuration of the installation according to the invention compared to three prior art installation configurations. Configuration No. 1, according to the prior art, corresponds to an installation with purely generator-powered electricity from the nuclear reactor, without energy optimization or any waste heat recovery.

[0132] Configuration No. 2 according to the state of the art corresponds to a generator supply from the nuclear reactor without recovery of waste heat but with a heat input with a temperature below 300°C without energy cost.

[0133] Configuration No. 2 according to the state of the art corresponds to an installation with generator power from the nuclear reactor without recovery of waste heat but with a heat input with a temperature below 300°C without energy cost.

[0134] Configuration No. 3 according to the invention corresponds to a heat return to the Rankine cycle coupled to the nuclear reactor, at a temperature of approximately 100°C which corresponds to the low-temperature waste heat of units 100 and 300.

[0135] Configuration No. 4 according to the invention corresponds to a heat return to the Rankine cycle coupled to the nuclear reactor, both at a temperature according to Table 1 which corresponds to the high temperature waste heat of units 100 and 300 and at a temperature according to Table 1 which corresponds to the low temperature waste heat of units 100 and 300.

[0136] These different configurations are represented in Figure 3. It is specified that the acronym SMR designates an SMR type nuclear reactor (power here of 100MW), SCE designates the Rankine cycle, EHT designates a high temperature electrolysis unit, FT designates a unit implementing a Fischer Tropsch process, RWGS designates a unit implementing the reverse reaction of gas to water, and DAC designates a direct CO2 capture unit.

[0137] The results of the power calculations for these different configurations are shown in Figure 4. It appears from these results that configuration No. 4 according to the invention allows an improvement in energy efficiency compared to configuration No. 1 according to the state of the art of 20.5% and compared to that according to configuration No. 3 according to the invention of 0.5%.

[0138] It is specified that the energy efficiency was calculated for a 100 MW nuclear reactor, it corresponds to the lower heating value of the liquid cut (C5+) divided by the core power of the nuclear reactor and it is represented in dark green on the exit bars.

[0139] The invention is not limited to the examples just described; in particular, features of the illustrated examples can be combined in unillustrated variants.

[0140] Other variants and embodiments may be considered without departing from the scope of the invention.

[0141] If, in the illustrated examples, the waste heat is reinjected respectively at the low-pressure reheating point for low temperatures, and at the superheating and high-pressure reheating points for high temperatures, we can consider more generally,

[0142] - a reinjection of low-temperature waste heat, at any point in the SCE system, with reinjection in series or in parallel with other heating systems; and / or

[0143] - a reinjection of the high-temperature waste heat into the cycle, at any point, in the SCE system, in particular at the superheat between the steam generator and the turbine, at the superheat between the turbines or at the reheat (at high or low pressure), with a reinjection in series or in parallel with other reheats in particular.

[0144] The nuclear cogeneration plant just described in relation to a pressurized water reactor can be implemented with all indirect-cycle nuclear reactors, where the heat production cycle is physically separated from the energy conversion cycle, such as a boiling water reactor or a Generation IV nuclear reactor involving different temperature levels in the conversion cycle. Thus, while the detailed example concerns a small pressurized water reactor (SMR), a cogeneration plant can be considered with a large or conventional reactor.

[0145] More generally, the invention can be implemented for any thermal power plant such as a solar, geothermal... power plant

[0146] The invention can be implemented with any unit for the production of synthetic molecules in which there is an exothermic reaction, such as the production of methanol, ammonia, or methane. The more exothermic and at higher temperatures the reaction, the greater the reinjection of waste heat back into the Rankine cycle and the improved the energy efficiency.

[0147] An improvement in the overall energy efficiency of an installation according to the invention could be observed by a production unit implementing a high-temperature Fischer Tropsch process of approximately 300°C.

[0148] If the installation according to the invention is described with a high temperature electrolysis unit (HTE), the invention can be implemented with alkaline electrolysis, PEM or AEM.

[0149] In cases where no heat is required for electrolysis:

[0150] - the low-temperature waste heat reinjection circuit is retained, because the Rankine cycle can still utilize this energy;

[0151] - the high-temperature waste heat reinjection circuit is still relevant, allowing the replacement of superheating upstream of the low-pressure turbine;

[0152] - The heat extraction loop at the output of the EHT 100 unit is removed, which allows for a further increase in electrical production.

[0153] For CO2 capture, technologies other than direct air capture (DAC) can be considered. For example, capture from flue gases or a concentrated CO2 stream from another process (such as methanation) can be implemented. In the latter case, the heat required by the cycle would be reduced or even eliminated, thus removing the loop at the outlet of the DAC 300 unit without compromising the effectiveness of the other connections.

[0154] The possibility of electrically connecting the installation to the grid can be envisaged, in particular to guarantee a fuel production base in the event of a shutdown / maintenance of the nuclear reactor or a transient operation, and / or in the case where the reactor is not solely dedicated to the production of fuels while maintaining a thermal connection with the process.

[0155] The installation can be supplied with heat by a nuclear reactor that is solely a heat generator.

[0156] A reforming unit can be implemented in the installation. Storage (CO2, H2, etc.) can also be considered within the installation.

[0157] List of cited references

[0158] [1]: Fujiwara et al. “Hydrogen production by high temperature electrolysis with nuclear reactor”, Progress in Nuclear Energy 50 (2008).

[0159] [2]: Richard D. Boardman et al. “Developing a low-cost renewable supply of hydrogen with high-temperature electrochemistry”, MRS Bulletin, volume 47, March 2022, mrs.org / bulletin.

[0160] [3]: Zang G. et al., “The modeling of Synfuel Production Process - ASPEN Model of FT production with electricity demand provided at LWR scale”, December 2021. https: / / publications.anl.gov / anlpubs / 2022 / 02 / 173337.pdf

[0161] [4]: Delgado et al., “Techno-economic analysis and life cycle analysis of e -fuel production using nuclear energy” Journal of CO2 Utilization, 72, 2023, 102481. http: / / dx.doi.org / 10.1016 / j.jcou.2023.102481

[0162] [5]: H.D. Nguyen, N. Alpy, D. Haubensack. “Insight on electrical and thermal powers mix with a Gen2 PWR: Rankine cycle performances under low to high temperature grade cogeneration.” Energy, Elsevier, 2020, 202, pp.117518. ffl0.1016 / j. energy.2020.117518ff. ffcea-02569231f.

[0163] [6]: D. Haubensack et al., “The COPERN1C / CYCLOP computer tool: pre-conceptual design of generation 4 nuclear systems, HTR-2004” , 2nd International Topic Conference for the HTGR, September 22-24, 2004, Beijing, China, 2004.

Claims

Demands 1. Electricity generation installation, intended to produce electricity and, where applicable, heat, comprising: - a thermal power plant (1) with a decarbonized heat source, with a thermal energy to electrical energy conversion system (CES); - at least one electrolysis unit (100), electrically connected to the SCE system and capable of being thermally coupled to the thermal power plant by a fluidic circuit, so as to be supplied respectively with the electricity and heat required for the electrolysis reaction; - at least one production unit (500) of at least one synthetic fuel or organic chemical compound, adapted to carry out an exothermic synthesis reaction; the production unit being connected to the electrolysis unit by a fluidic circuit so as to be supplied with hydrogen; - at least one fluidic circuit (600, 700), called high temperature and / or low temperature reinjection coupling circuit, to thermally couple the output of the production unit to at least a part of the SCE system so as to reinject at least a part of the so-called high temperature and / or low temperature waste heat produced by the exothermic synthesis reaction into the SCE system.

2. Installation according to claim 1, the heat transfer fluid of the high-temperature reinjection coupling circuit being at a temperature of at least 150°C, advantageously between 200 and 350°C, advantageously between 215 and 275°C.

3. Installation according to claim 1 or 2, the heat transfer fluid of the low-temperature reinjection coupling circuit being at a temperature of at least 80°C, advantageously between 80 and 150°C, advantageously between 80 and 100°C.

4. An installation according to any one of the preceding claims, wherein: - The SCE system implements a Rankine cycle comprising: • at least one steam generator (3), • at least one turbine (6, 60) comprising a high-pressure body (60) connected to the steam generator and a low-pressure body (61) connected to the high-pressure body by at least one fluidic branch (62), • a high-pressure heater (64) connected to the high-pressure body (60), to a water tank, called a feed tank (66), and to the steam generator (30), • a low-pressure heater (65) connected on one side by at least one fluid branch to the low-pressure body (61) and on the other side by at least one fluid branch to the feed tank, • a condenser (7), connected on one side to the low pressure body and on the other side to the low pressure heater; - The high-temperature reinjection coupling circuit includes: • a heat exchanger (702) connected on one side in a closed loop to the outlet of the production unit of at least one synthetic fuel and on the other side at the inlet to the high-pressure body (60) and at the outlet to the low-pressure body (61), and / or • a heat exchanger (704) connected on one side in a closed loop to the outlet of the production unit of at least one synthetic fuel and on the other side upstream of the high-pressure heater (64) and at the outlet to the steam generator (3), and / or • a heat exchanger connected on one side in a closed loop to the outlet of the production unit of at least one synthetic fuel and on the other side at the inlet to the high-pressure body and at the outlet to the high-pressure heater (64), and / or • a heat exchanger connected on one side in a closed loop to the outlet of the production unit of at least one synthetic fuel and on the other side at the inlet to the low-pressure body and at the outlet to the low-pressure heater, and / or • a heat exchanger (602) connected on one side in a closed loop to the outlet of the cooler and on the other side at the inlet between the condenser and the low pressure heater (65) and at the outlet between the low pressure heater (65) and the food tank (66).

5. Installation according to any one of the preceding claims, further comprising at least one direct carbon dioxide capture (DAC) unit, connected to the production unit of at least one synthetic fuel by a fluidic circuit and thermally coupled to the thermal power plant by a fluidic circuit so as to respectively supply the production unit with CO2 necessary for the exothermic synthesis reaction and to be supplied with heat necessary for the direct capture of CO2.

6. Installation according to any one of claims 4 or 5, further comprising, at the outlet of the cooler, a low-temperature preheater for the electrolysis unit and, where applicable, a low-temperature preheater for the direct carbon dioxide capture (DAC) unit, 7. Installation according to any one of the preceding claims, the synthetic fuel production unit being adapted to implement a reverse water gas shift (RWGS) process and / or a Fischer-Tropsch (FT) process and where appropriate a reforming process.

8. Installation according to any one of the preceding claims, the thermal power plant comprising at least one nuclear reactor, in particular a pressurized water reactor (PWR) or a boiling water reactor (BWR) or a fast neutron reactor in particular cooled with sodium (NaFNR).

9. Installation according to any one of the preceding claims, the SCE system implementing a Rankine cycle comprising an alternator adapted to supply at least part of its electricity to the electrolysis unit (100) and where appropriate to the direct carbon dioxide capture (DAC) unit.

10. Installation according to any one of the preceding claims, the electrolysis unit being a high-temperature electrolysis (100).

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