FR3122670A1 - High temperature electrolyser system with optimized energy consumption - Google Patents

Abstract

High-temperature electrolyser system with optimized energy consumption The invention relates to a system comprising: - a high-temperature (EHT) electrolyser (1), - a first steam supply line (2), - a first dihydrogen evacuation line (4), - a second dioxygen evacuation line (3), - a first steam generator (6) arranged on the first supply line (2), characterized in that - the first supply line (2) comprises a main section (36) and a depression section (35), - the system comprises: *a depression module for the depression section (35) comprising a pressure reducer (8) and a compressor (9), and a second vacuum steam generator (7) arranged on the vacuum section (35) between the expander (8) and the compressor (9), - the first and second steam generators (6 ) (7) are heat exchangers also arranged on the first evacuation line (4), the first generator steam (6) being arranged upstream of the second steam generator (7). Figure for abstract: Fig.1

Description

High temperature electrolyser system with optimized energy consumption

The present invention relates to the field of electrolysis of water at high temperature (EHT, or EVHT for electrolysis of water vapor at high temperature, or HTE English acronym for High Temperature Electrolysis, or HTSE English acronym for High Temperature Steam Electrolysis), also solid oxide (SOEC, English acronym for " Solid Oxide Electrolyte Cell ") and that of solid oxide fuel cells (SOFC, English acronym for " Solid Oxide Fuel Cell ). It finds application particularly in optimizing the energy consumption of a SOEC electrolyser system.

STATE OF THE ART

Water electrolysis is an electrolytic reaction that decomposes water into dioxygen and dihydrogen gas with the help of an electric current according to the reaction: H ₂ O → H ₂ + 1/2 O ₂ .

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 necessary for the reaction can be provided by heat, which is less expensive than electricity and the activation of the reaction is more efficient at high temperature and does not require a catalyst. A solid oxide electrolysis cell or "SOEC" (Anglo-Saxon acronym "Solid Oxide Electrolyte Cell") comprises in particular: - a first porous conductive electrode, or "cathode", intended to be supplied with steam for the production of dihydrogen, - a second porous conductive electrode, or "anode", through which escapes the dioxygen produced by the electrolysis of the water injected on the cathode, and - a solid oxide membrane (dense electrolyte) taken into sandwiched between the cathode and the anode, the membrane being anionic conductor for high temperatures, usually temperatures above 600°C. By heating the cell to at least this temperature and by injecting an electric current I between the cathode and the anode, there is then a reduction of water on the cathode, which generates dihydrogen (H2) at the level of the cathode and oxygen at the anode. To implement electrolysis at high temperature, it is known to use an electrolyser of the SOEC type consisting of a stack of elementary units each comprising a solid oxide electrolysis cell, consisting of three anode/electrolyte/cathode layers. superposed one on the other, and interconnection plates in metal alloys also called bipolar plates, or interconnectors. The function of the interconnectors is to ensure both the passage of electric current and the circulation of gases in the vicinity of each cell (water vapor injected, hydrogen and oxygen extracted in an EHT electrolyser; air and hydrogen injected and water extracted in a SOFC cell) and to separate the anode and cathode compartments which are the gas circulation compartments on the side respectively of the anodes and the cathodes of the cells.

To carry out the electrolysis of water vapor at high temperature EHT, water vapor H2O is injected into the cathode compartment.

Under the effect of the current applied to the cell, the dissociation of water molecules in vapor form is carried out at the interface between the hydrogen electrode (cathode) and the electrolyte: this dissociation produces dihydrogen gas H2 and oxygen ions. The dihydrogen is collected and evacuated at the outlet of the hydrogen compartment. The oxygen ions migrate through the electrolyte and recombine into dioxygen O ₂ at the interface between the electrolyte and the oxygen electrode (anode).

For the effective implementation of the electrolysis by the stack, the stack is brought to a temperature above 600° C., usually a temperature between 600° C. and 950° C., the gas supply is brought to running at a constant rate and an electrical power source is connected between two terminals of the stack in order to cause the current I to flow there.

The efficiency of the transformation of electricity into hydrogen is a key point in order to ensure the competitiveness of the technology. Electricity consumption mainly takes place during the electrolysis reaction itself, but almost 30% of the consumption of the electrolyser comes from the thermal/hydraulic fluid management system. That is to say the architecture external to the electrolyser and the management of fluids and thermal energy in this architecture.

The evaporation of the water used in the electrolyser is the most important energy consumption of this thermal/hydraulic management system. Conventionally, this function is provided by an electric steam generator which consumes 20% of the overall consumption of the electrolyser.

Moreover, in general, a significant part of the energy is released into the surrounding environment. For example, during the hydrogen drying and compression phase, it is necessary to greatly cool this mixture in order to allow the condensation of the water present in the water/hydrogen mixture. This condensation takes place for the most part at a temperature below the evaporation temperature of the water entering the electrolyser, which means that a very small part of this condensation energy is usable.

There is therefore a need to minimize this consumption by optimizing the architecture and fluid management of the electrolyser system.

An object of the present invention is therefore to provide an optimized high temperature electrolyser system.

The other objects, features and advantages of the present invention will become apparent from a review of the following description and the accompanying drawings. It is understood that other benefits may be incorporated.

SUMMARY

• la première ligne d'alimentation de l'électrolyseur en vapeur d'eau comprend un tronçon principal et un tronçon en dépression,
• le système comprend un module de mise en dépression du tronçon en dépression de la première ligne d'alimentation, le module comprenant un détendeur et un compresseur,
• le système comprend un deuxième générateur de vapeur en dépression agencé sur le tronçon en dépression entre le détendeur et le compresseur,
• le premier générateur de vapeur et le deuxième générateur de vapeur sont des échangeurs thermiques agencés également sur la première ligne d'évacuation du dihydrogène, le premier générateur de vapeur étant agencé en amont du deuxième générateur de vapeur relativement à la première ligne d'évacuation du dihydrogène.

To achieve this objective, according to one embodiment, a system is provided comprising:
a high temperature electrolyser (EHT),
a first supply line of the electrolyser configured to supply the electrolyser with steam,
a first discharge line from the electrolyser configured to discharge dihydrogen from the electrolyser,
a second discharge line from the electrolyser configured to discharge dioxygen from the electrolyser,
a first steam generator arranged on the first steam supply line, and configured to produce steam from liquid water,
characterized in that

• the first line for supplying the electrolyser with steam comprises a main section and a depression section,
• the system comprises a module for creating a vacuum in the vacuum section of the first supply line, the module comprising a pressure reducer and a compressor,
• the system comprises a second vacuum steam generator arranged on the vacuum section between the expander and the compressor,
• the first steam generator and the second steam generator are heat exchangers also arranged on the first hydrogen evacuation line, the first steam generator being arranged upstream of the second steam generator relative to the first hydrogen evacuation line dihydrogen.

This arrangement makes it possible to recover the calories from the dihydrogen produced by the electrolyser for the benefit of the production of steam. By the present system, the steam generators allow both the cooling of the dihydrogen and the production of steam. Thus, the power consumption of the system is greatly reduced. Advantageously, the use of a steam generator on a section under depression makes it possible to lower the evaporation temperature of the water and thus makes it possible, by recovering thermal energy from the dihydrogen having already been cooled by the first generator of steam to be able to participate in the production of steam.

The system thus makes it possible to reduce the electricity consumption of the system by increasing the thermal power drawn off.

BRIEF DESCRIPTION OF FIGURES

The aims, objects, as well as the characteristics and advantages of the invention will emerge better from the detailed description of an embodiment of the latter which is illustrated by the following accompanying drawings in which:

The is a block diagram representing the system according to one embodiment of the invention.

The represents a detailed block diagram of part of the system according to the embodiment of the invention illustrated in .

The represents a block diagram representing the system according to a variant of the invention.

The is a functional diagram representing the heat pump according to a first possibility.

The is a functional diagram representing the heat pump according to a second possibility.

The drawings are given by way of examples and do not limit the invention. They constitute schematic representations of principle intended to facilitate understanding of the invention and are not necessarily scaled to practical applications.

DETAILED DESCRIPTION

Before starting a detailed review of embodiments of the invention, optional characteristics are set out below which may possibly be used in combination or alternatively:

According to one example, the system comprises a third steam generator 20 arranged on the first steam supply line 2, upstream of the first steam generator 6 and on the first evacuation line 4 of the dihydrogen downstream of the second steam generator 7 configured to produce steam from liquid water.

According to one example, the system comprises a fourth steam generator 21 arranged on the depression section 35 of the first steam supply line 2, upstream of the second steam generator 7 and on the first evacuation line 4 hydrogen downstream of the third steam generator 20 configured to produce steam from liquid water.

According to one example, the system comprises a fifth steam generator 24 arranged on the first steam supply line 2, upstream of the third steam generator 20 and on the first evacuation line 4 of the dihydrogen downstream of the fourth steam generator 21 configured to produce steam from liquid water.

According to one example, the system comprises a sixth steam generator 25 arranged on the depression section 35 of the first steam supply line 2, upstream of the fourth steam generator 21 and on the first evacuation line 4 dihydrogen downstream of the fifth steam generator 24 configured to produce steam from liquid water.

According to one example, the system comprises a first heat exchange module 5 configured to ensure a heat exchange between the first steam supply line 2 and the first evacuation line 4 of the dihydrogen, the first module of heat exchange 5 being arranged on the first steam supply line 2 downstream of the steam generators and on the first evacuation line 4 of the dihydrogen upstream of the steam generators.

According to one example, the system comprises a heater 15 arranged on the first steam supply line 2 upstream of the first heat exchange module 5 and downstream of the steam generators.

According to one example, the system comprises a seventh steam generator 42 arranged on the first steam supply line 2, upstream of the first steam generator 6 and on the second exhaust line 3 of the electrolyser configured to evacuate from the electrolyser 1 oxygen configured to produce water vapor from liquid water.

According to one example, the system comprises an eighth steam generator 43 arranged on the depression section of the first steam supply line 2, upstream of the second steam generator 7 and on the second evacuation line 3 of the electrolyser configured to evacuate from the electrolyser 1 oxygen downstream of the seventh steam generator 42 configured to produce steam from liquid water.

According to one example, the system comprises at least a liquid/gas separator 18 arranged on the first dihydrogen evacuation line 4 downstream of the steam generators.

According to one example, the water circulating in the main section 36 and/or in the depression section 35 is at least partly water resulting from the drying out of the dihydrogen by a liquid/gas separator 18 arranged on the first line evacuation 4 of dihydrogen, for example downstream of the steam generators.

According to one example, the system comprises a dihydrogen thermal energy recovery module for the benefit of the first steam supply line 2, the recovery module comprising a heat pump comprising
a fluidic circuit 31 configured to receive a heat transfer fluid,
an evaporator 17 arranged on the first evacuation line 4 downstream of the second steam generator 7 on the depression section 35, configured to transfer the thermal energy from the dihydrogen to the heat transfer fluid,
a compressor 29 configured to compress the heat transfer fluid,
a condenser 16 arranged on the first steam supply line 2 on the depression section 35 in parallel with the second steam generator 7, configured to transfer thermal energy from the heat transfer fluid to liquid water,
an expansion valve 30 configured to expand the heat transfer fluid,
the fluidic circuit 31 being configured to fluidically connect the evaporator 17 to the compressor 29, the compressor 29 to the condenser 16, the condenser 16 to the expander 30 and the expander 30 to the evaporator 17.

This arrangement makes it possible to recover the thermal energy of the dihydrogen produced by the electrolyser to participate in the evaporation of liquid water and therefore reduce the energy consumption of the system while taking into account the constraints of the components to allow the use of classic components.

Thus, the system uses the heat of the dihydrogen at the output of the electrolyser, after the steam generators, so that the thermal rejection of the dihydrogen in the evaporator is exploited at a lower temperature via an active system of a heat pump. . The calories recovered from the dihydrogen are reinjected at a temperature above the evaporation temperature of the water on the depression section in parallel with the second steam generator.

The heat pump thus arranged makes it possible to operate with an interesting efficiency due to the low temperature difference between the evaporation temperature of the water in the condenser and the temperature of the hydrogen flow in the evaporator.

According to one example, the heat pump comprises an additional evaporator 17b configured to take calories from an external source, the additional evaporator 17b being arranged in parallel with the evaporator 17.

According to one possibility, the heat pump comprises a single compressor.

According to another possibility, the heat pump comprises a compressor arranged downstream of each of the evaporators.

The upstream and downstream, the entry, the exit, at a given point are taken in reference to the direction of circulation of the fluid.

A parameter "substantially equal/greater/less than" a given value means that this parameter is equal/greater/less than the given value, to within plus or minus 10%, or even within plus or minus 5%, of this value

The system according to the invention comprises a high temperature electrolyser 1 (EHT). Preferably, the electrolyser 1 is of the SOEC type, the English acronym for “ Solid Oxide Electrolyte Cell ”, that is to say with solid oxide.

The system comprises several supply and evacuation lines connected to the electrolyser 1. Thus, by line is meant a pipe, a tube or a set of pipes or tubes which allow the transport of fluid to and from the electrolyser 1 .

The system according to the invention comprises a first supply line 2 of the electrolyser 1 capable of supplying the electrolyser 1 with steam. According to one possibility, the first supply line 2 is configured to supply the electrolyser 1 with steam, by which is meant that the first supply line 2 can supply a mixture of steam and other gas(es), for example air or dihydrogen or carbon dioxide. Upstream in this first supply line 2, water vapor has not yet formed and the first supply line 2 is configured to receive liquid water. According to a preferred possibility, the first supply line 2 comprises a first part receiving liquid water and a second part receiving steam. Preferably, the first part is located upstream of a steam generator and the second part is located downstream of said steam generator.

The system according to the invention comprises a first evacuation line 4 able to evacuate dihydrogen (H ₂ ) from the electrolyser 1 . Preferably, the first evacuation line 4 receives the dihydrogen. The dihydrogen is advantageously produced by the electrolyser 1. The dihydrogen is in gaseous form. The first evacuation line 4 can evacuate a mixture of dihydrogen and water vapour, called residual which has not been decomposed by the electrolyser 1.

The system according to the invention comprises a second evacuation line 3 able to evacuate dioxygen (O ₂ ) from the electrolyser 1 . Preferably, the second evacuation line 3 receives the oxygen. The oxygen is advantageously produced by the electrolyser 1. The oxygen is in gaseous form. The second evacuation line 3 evacuates according to one possibility a gas enriched in oxygen, for example air enriched in oxygen.

In the rest of the description, the first supply line 2 is called the first steam supply line 2, the first evacuation line 4 is called the first evacuation line 4 of dihydrogen and the second line of evacuation 3 is called second evacuation line 3 in dioxygen without being limiting on the gas, the fluid or the mixture which can be transported in these lines.

According to one possibility, the system comprises a first heat exchange module 5 configured to ensure a heat exchange between the first steam supply line 2 and the first evacuation line 4 for dihydrogen. This heat exchange module is configured to transfer the calories of the dihydrogen from the electrolyser 1 to the water, liquid or steam, intended to supply the electrolyser 1. A flow of dihydrogen gas ensures the temperature increase of the this water flow while also making it possible to cool the flow of dihydrogen evacuated and which is advantageously dried and/or compressed with a view to its use.

The first heat exchange module 5 comprises according to one embodiment at least one heat exchanger 5a configured to ensure the heat transfer from dihydrogen to steam. According to a preferred embodiment, the first heat exchange module 5 comprises two heat exchangers 5a, 5b arranged in series between the first supply line 2 and the first evacuation line 4. This arrangement makes it possible to provide a second heat exchanger thermal 5b adapted to the temperature of the dihydrogen at the outlet of the electrolyser 1, conventionally of the order of 700° C., and a more usual first heat exchanger 5a adapted to the temperature of the dihydrogen after passing through a heat exchanger, or conventionally around 330°C. In this way, the components are optimized for the temperatures and heat transfers to be achieved.

According to one embodiment, the system comprises a second supply line 10 capable of supplying the electrolyser 1 with air. Preferably, the second supply line 10 receives air. According to one possibility, the second supply line 10 is configured to supply air to the electrolyser 1, by which is meant that the second supply line 10 can supply air, the air being for example a gaseous mixture which makes it possible to sweep the cell of the electrolyser 1 and to take away the dioxygen produced by the electrolyser 1 .

According to this embodiment, it is advantageous for the system according to the invention to comprise a second heat exchange module 11 configured to ensure heat exchange between the second air supply line 10 and the second exhaust line 3 of the dioxygen. This heat exchange module 11 is configured to transfer the calories of the dioxygen from the electrolyser 1 to the air intended to supply the electrolyser 1. A flow of dioxygen gas ensures the increase in the temperature of the flow of air which also makes it possible to cool the flow of oxygen evacuated.

The second heat exchange module 11 comprises according to one embodiment at least one heat exchanger 11a configured to ensure the heat transfer from the oxygen to the air. According to a preferred embodiment, the second heat exchange module 11 comprises two heat exchangers 11a, 11b arranged in series between the second supply line 10 and the second evacuation line 3. This arrangement makes it possible to provide a second heat exchanger thermal 11b adapted to the temperature of the oxygen at the outlet of the electrolyser 1, conventionally of the order of 700° C., and a more usual first heat exchanger 11a adapted to the temperature of the oxygen after passage through a heat exchanger, or conventionally around 330°C. In this way, the components are optimized for the temperatures and heat transfers to be achieved.

The system preferably comprises a compressor 12 arranged on the second supply line 10 intended for the air supply. The compressor 12 is preferably arranged upstream of the second heat exchange module 11, if present. The compressor 12 is intended to ensure the compression of the air intended to be supplied to the electrolyser 1. The compression of the air advantageously contributes to increasing the temperature of the air before it enters the electrolyser.

According to one embodiment, the system according to the invention comprises a first steam generator 6. The first steam generator 6 is configured to produce steam from liquid water. Preferably, the first steam generator 6 is arranged on the first steam supply line 2 . According to this embodiment, the system also comprises a second steam generator 7. The second steam generator 7 is also configured to produce steam from liquid water. The second steam generator 7 is also arranged on the first steam supply 2 .

Preferably, according to this embodiment, the first steam supply line 2 comprises a main section 36 and a depression section 35. The main section 36 and the depression section 35 are arranged in parallel to form less in part the first steam supply line 2. Preferably, in the main section 36 there is a pressure at least equal to atmospheric pressure, preferably of the order of 1 to 2 bars, for example 1.7 bars.

In the depression section 35 there is a pressure lower than the pressure of the main section 36, preferably a pressure lower than atmospheric pressure, by way of example, a pressure of the order of 0.4 bars may be provided in the depression section 35.

According to one embodiment, the system comprises a module for creating a depression of the depression section 35. The module for creating a depression includes an expander 8 and a compressor 9. The depression section 35 thus extends between the expander 8 in upstream and the compressor 9 downstream.

According to an advantageous aspect of the invention, the second steam generator 7 is arranged on the depression section 35, preferably between the expander 8 upstream and the compressor 9 downstream. The second steam generator 7 thus operates under vacuum, which lowers the evaporation temperature of the liquid water, thus reducing the energy required for this phase change.

According to a possibility illustrated in , the system comprises a stepped compression downstream of the depression section 35. According to this possibility, the system comprises two compressors 9a and 9b, arranged in series on the first supply line 2, preferably on the depression section 35. Advantageously, the system comprises a heat exchanger 32 arranged between the two compressors 9a and 9b. The heat exchanger 32 is configured to ensure the transfer of thermal energy between the first supply line 2, more particularly the depression section 35 and an external water inlet 34 supplying the first supply line 2. The heat exchanger heat 32 makes it possible to use the thermal energy of the steam produced by the at least one vacuum steam generator 7, 21 or 25 and/by the condenser 16 of the heat pump for the benefit of the external water. The external water arriving at a temperature of 20° at a pressure of the order of 1 bar in the external water inlet 34 emerges from the heat exchanger 32 at a temperature of the order of 110°C. In the depression section 35, the water vapor leaves the first compressor 9a at a temperature of the order of 160° C. for a pressure of 1 bar, then leaves the heat exchanger 32 at a temperature of the order 120°C for a pressure of 1 bar. The water vapor is then compressed by the second compressor 9b to reach a temperature of the order of 180° C. and a pressure of 1.7 bars. This arrangement makes it possible, for the same thermal power transmitted to the condenser 16 of the heat pump, to have a reduced electricity consumption due to a gain in the efficiency of the system. The system thus makes it possible to reduce the electrical consumption of the system by improving the electrical efficiency of the system.

According to one possibility, the system comprises an inlet, not shown, of external vapor under depression. The vacuum steam is advantageously injected into the first supply line 2, preferably in the vacuum section 35, preferably upstream of the compressor 9, preferably downstream of the condenser 16 or of the vacuum steam generator 7.

Preferably, the first steam generator 6 is arranged on the main section at 36.

According to a preferred embodiment of the invention, the first steam generator 6 and the second steam generator 7 are heat exchangers transferring the calories from the first evacuation line 4 of the dihydrogen to the benefit of the first supply line 2 in water vapour. The first steam generator 6 and the second steam generator 7 are preferably arranged at the interface between the first evacuation line 4 of the dihydrogen and the first supply line 2 of steam.

According to a preferred possibility, the first steam generator 6 is arranged upstream of the second steam generator 7 relative to the first evacuation line 4 of the dihydrogen. The first steam generator 6 and the second steam generator 7 are arranged in series on the first evacuation line 4 of the dihydrogen. In this way, the first steam generator 6 operating at the pressure of the electrolyser 1 recovers the calories from the dihydrogen produced by the electrolyser 1 first. Then the second steam generator 7 operating under depression recovers the calories from the dihydrogen at the outlet of the first steam generator 6. The first steam generator 6 requires a temperature of the dihydrogen higher than that necessary for the second steam generator 7 to transform the water liquid to water vapour.

Preferably, the first steam generator 6 and the second steam generator 7 are arranged on the first evacuation line 4 downstream of the heat exchange module 5.

The steam generator 6, 20, 24, 42 arranged on the main section 36 allows the production of steam, advantageously so-called dry steam, that is to say with no remaining liquid water and which may or may not be overheated.

The steam generator 7, 21, 25, 43 arranged on the depression section 35 allows the production of steam, in particular so-called wet steam, that is to say involving a portion of liquid water. Preferably, this wet steam is treated to become dry steam before the electrolyser 1 to allow the heaters 14, 15 and/or the heat exchangers 5a, 5b to operate with gas/gas exchanges.

The first steam generator 6 and the second steam generator 7 form an assembly called the exchanger train, more precisely the first exchanger train.

According to an advantageous embodiment, the liquid water supplying the first supply line 2 with water vapor is at least partly derived from the process for drying the dihydrogen produced by the electrolyser 1. This arrangement makes it possible to recycle the water taken away with the dihydrogen in the electrolyser 1.

According to one aspect of the invention, the system comprises a module for recovering the thermal energy of the dihydrogen produced by the electrolyser for the benefit of the first steam supply line 2.

According to one possibility, the recovery module comprises a heat pump arranged between the first evacuation line 4 of the dihydrogen and the first supply line 2 of steam. The heat pump is configured to transfer thermal energy from dihydrogen to liquid water.

The heat pump, particularly illustrated in detail in , comprises a condenser 16, an expander 30, at least one evaporator 17, and a compressor 29. The heat pump comprises a fluid circuit 31 capable of receiving a heat transfer fluid.

The heat transfer fluid is for example a fluid conventionally used in heat pumps such as 1234yf: 2,3,3,3-tetrafluoropropene (HFO-1234yf), or R245FA pentafluoropropane, or R290 propane

The fluidic circuit 31 ensures the fluidic connection of the components of the heat pump, preferably in a closed circuit.

According to an embodiment illustrated in , the fluidic circuit 31 comprises a fluidic connection 300 connected between the outlet of the compressor 29 and the inlet of the condenser 16. Advantageously, the fluidic circuit 31 comprises a fluidic connection 301 connected between the outlet of the condenser 16 and the inlet of the expander 30 Advantageously, the fluidic circuit 31 comprises a fluidic connection 302 connected between the outlet of the expansion valve 30 and the inlet of the evaporator 17.

According to the invention, the condenser 16 of the heat pump is arranged on the first steam supply line 2 in parallel with the second steam generator 7 to transmit calories from the heat transfer fluid to the water liquid flowing in the depression section 35 of the first supply line 2 in parallel with the second steam generator 7. According to this possibility, the depression section comprises two parallel branches. A first branch receives at least one vacuum steam generator and a second branch receives at least the condenser 16.

According to one embodiment of the invention, the evaporator 17 of the heat pump is arranged on the first evacuation line 4 of the dihydrogen, preferably downstream of the first steam generator 6 and of the second steam generator 7. This This arrangement is advantageous for allowing the heat pump to extract the calories from the dihydrogen produced at a temperature preferably below 75°C.

Preferably, the evaporator 17 is arranged upstream of the first liquid/gas separator 18. The evaporator 17 ensures the transfer of energy between the dihydrogen circulating in the first evacuation line 4 and the heat transfer fluid circulating in the fluidic circuit 31 of the heat pump.

According to a possibility illustrated in , the heat pump comprises two evaporators 17a, 17b arranged in parallel on the fluidic circuit, each with an expander 30a, 30b and a compressor 29a, 29b. The second heat exchanger 17b is configured to ensure the recovery of thermal energy from an external source. The calories can be taken from the ambient air, water, geothermal energy, or from a thermal discharge or heat source. The heat pump can comprise one or two compressors 29a, 29b depending on the assumptions of external sources.

The present invention makes it possible to exploit the waste heat of the system and more particularly the thermal discharges of the dihydrogen produced. The heat pump is an active system making it possible to reinject steam generators 6, 7 in parallel and at a temperature above the evaporation temperature of the water, the calories taken from the dihydrogen produced. Advantageously, the fact that the condenser 16 is arranged on the depression section makes it possible to lower the evaporation temperature of the liquid water in the condenser, making it possible to optimize energy recovery and to advantageously use a heat pump. 'conventional'.

According to one embodiment of the invention, the system comprises a heater 15 configured to provide additional thermal energy to participate in reaching the operating temperature of the electrolyser. The heater 15 is for example an electrical resistor configured to heat the steam flowing in the first steam supply line 2 . The power of the heater 15 is regulated to control the temperature of the water vapor at the inlet of the heat exchange module 5 so as not to degrade the operation of the latter.

According to a preferred embodiment, the system comprises at least one other exchanger train arranged at the interface of the first evacuation line 4 of the dihydrogen and the first supply line 2 of steam. Preferably, the system comprises two trains of additional exchangers.

Each exchanger train includes a steam generator operating at the pressure of electrolyser 1 and a steam generator operating under depression. In each exchanger train, the steam generator operating at the highest pressure is arranged on the first evacuation line 4 of the dihydrogen upstream of the steam generator operating under vacuum.

According to one possibility, a second exchanger train comprises a third steam generator 20 and a fourth vacuum steam generator 21 . The third steam generator 20 corresponds in its operation to the first steam generator 6. The third steam generator 20 is arranged at the interface between the first supply line 2, more precisely the main section 36, and the first line of evacuation 4. The third steam generator 20 is arranged upstream of the first steam generator 6 on the main section 36. The third steam generator 20 is arranged on the first evacuation line 4 downstream of the first exchanger train formed by the first steam generator 6 and the second steam generator 1. The fourth steam generator 21 corresponds in its operation to the second steam generator 7. The fourth steam generator 21 is arranged at the interface between the first supply line 2, more precisely the depression section 35, and the first evacuation line 4. The fourth steam generator 21 is arranged downstream of the second steam generator 7 s on the depression section 35. The fourth steam generator 21 is arranged on the first evacuation line 4 downstream of the fourth steam generator 20.

According to one possibility, a third exchanger train comprises a fifth steam generator 24 and a sixth vacuum steam generator 21. The fifth steam generator 24 corresponds in its operation to the first steam generator 6. The fifth steam generator 24 is arranged at the interface between the first supply line 2, more precisely the main section 36, and the first discharge line 4. The fifth steam generator 24 is arranged upstream of the first steam generator 6 on the main section 36 , preferably upstream of the third steam generator 20. The fifth steam generator 24 is arranged on the first evacuation line 4 downstream of the first exchanger train and preferably downstream of the second exchanger train. The sixth steam generator 25 corresponds in its operation to the second steam generator 7. The sixth steam generator 25 is arranged at the interface between the first supply line 2, more precisely the depression section 35, and the first line evacuation 4. The sixth steam generator 25 is arranged upstream of the second steam generator 7 on the depression section 35, preferably upstream of the fourth steam generator 21. The sixth steam generator 25 is arranged on the first line evacuation 4 downstream of the fifth steam generator 24.

According to one embodiment, the system comprises an exchanger train arranged at the interface of the second evacuation line 3 of dioxygen and the first supply line 2 of steam. This train of exchangers comprises a steam generator 42, also called seventh steam generator 42, corresponding in its operation to the first steam generator 6. The seventh steam generator 42 operates at the pressure of the electrolyser 1. The seventh steam generator steam 42 is arranged on the main section 36 of the first supply line 2. Preferably, the seventh steam generator 42 is arranged upstream of the first steam generator 6, preferably also upstream of the third and fifth steam generator, if present. Indeed, the calories recovered by the first steam generator 6 are greater than those recovered by the seventh steam generator 42. In this way, the calories recovered by the seventh steam generator 42 allow preheating of the liquid water upstream at least of the first steam generator 6.

According to this embodiment, the exchanger train comprises a steam generator 43, also called eighth steam generator 43, corresponding in its operation to the second steam generator 7. The eighth steam generator 43 operates under depression with respect to the pressure of the electrolyser 1. The eighth steam generator 43 is arranged on the depression section 35 of the first supply line 2, preferably, the eighth steam generator 43 is arranged upstream of the second steam generator 7. In Indeed, the calories recovered by the second steam generator 7 are greater than those recovered by the eighth steam generator 43.

According to one embodiment, the system comprises means for processing the flow of dihydrogen produced. The dihydrogen produced by the electrolyser 1 and which emerges therefrom via the first evacuation line 4 first of all has a very high temperature corresponding to the reaction temperature of the electrolyser 1. However, with a view to its use, the dihydrogen should preferably be brought to a temperature close to room temperature. Furthermore, the dihydrogen evacuated from the electrolyser 1 via the first evacuation line 4 can comprise water vapor carried away with the flow of dihydrogen. It is therefore also preferred to separate the dihydrogen from any water vapor carried away with it, by drying it.

The system according to the invention advantageously comprises for this purpose at least one first treatment stage 44 intended for the drying and/or compression of the dihydrogen produced.

According to one possibility, the first treatment stage 44 comprises a heat exchanger 17 advantageously corresponding to the evaporator 17 of the heat pump. According to another possibility, the heat exchanger is an air cooler or a cooler. The air cooler is a heat exchanger between a fluid and a gas, the gas being set in motion by a fan. Alternatively, the dry cooler is replaced by a standard cooler or a condenser, i.e. without a fan, although this solution is less efficient. For the rest of the description, the term air cooler is used without being limiting, the air cooler can be replaced by a standard cooler, or a condenser without difficulty.

The first treatment stage 44 advantageously comprises a liquid/gas separator 18 arranged downstream of the evaporator 17. The separator 18 makes it possible to separate the liquid water from the gaseous dihydrogen, the liquid water resulting from the cooling of the vapor of water in the evaporator 17 below its dew point. The separator 18 therefore contributes to reducing the flow rate of the circulating stream and therefore the compression.

According to a preferred possibility, the system comprises a second stage of treatment 45 arranged downstream of the first stage of treatment 44 on the first evacuation line 4. The second stage of treatment 45 participates in the compression of the dihydrogen. The second processing stage 45 advantageously comprises at least one compressor 19, 23 arranged on the first evacuation line 4 of the dihydrogen. The system can comprise at least two compressors 19, 23 arranged on the first evacuation line 4 of dihydrogen. Preferably, the compressors 19, 23 are arranged in series, more preferably the system comprises a heat exchanger 22 such as an air cooler arranged between two compressors 19, 23. The presence of an air cooler type heat exchanger 22, for example between the compressors 19 , 23 makes it possible to ensure a reduction in the temperature of the fluid circulating from one compressor 19 to the other compressor 23, and therefore a reduction in the pressure and its flow rate facilitating the work of the next compressor 23.

According to a preferred embodiment, the second exchanger train formed by the third steam generator 20 and the fourth steam generator 21 is arranged at the level of the second treatment stage 45, preferably downstream of the compressor 19 and upstream of the heat exchanger 22.

According to a preferred possibility, the system comprises a third treatment stage 46 arranged downstream of the second treatment stage 45 on the first evacuation line 4. The third treatment stage 46 makes it possible to complete the drying of the dihydrogen. The third treatment stage 46 preferably comprises a dry cooler 26 which, as for the other stages, can be a standard cooler. The third processing stage 46 preferably comprises a liquid/gas separator 28.

Preferably, the third treatment stage 46 is arranged downstream of the third exchanger train formed by the fifth steam generator 24 and the sixth steam generator 25.

At the end of the first processing stage 44 and/or the third processing stage 46 if present, the liquid water is preferably recycled, for example by being returned to the first steam supply line 2 by a line water recycling line 33. The water recycling line 33 can be fluidically connected to the first supply line 2.

According to a preferred embodiment, the system includes a controller configured to control the operation of the system. For example, the controller provides control of the system's three-way valves. Three-way valves are configured to regulate fluid inlets and outlets. For example, the three-way valve 38 regulates the quantity of liquid water transmitted to the main section 36 and the depression section 35. For example, the three-way valve 39 regulates the quantity of liquid water transmitted to the first branch of the section under depression 35 and to the second branch of the section under depression 35. For example, the three-way valve 40 regulates the quantity of steam recovered from the first branch of the section under depression 35 and from the second branch of the section under depression 35. For example, the three-way valve 41 controls the amount of steam recovered from towards the main section 36 and the section under depression 35, that is to say the amount of wet steam relative to the amount of dry steam sent downstream of supply line 2.

The electrolyser 1 receives water vapor and advantageously air and rejects dihydrogen and dioxygen.

Preferably, the electrolyser 1 is fluidically connected to the first steam supply line 2. The first steam supply line 2 ensures the fluidic connection of components arranged upstream of the electrolyser 1 on said first supply line 2. The following description is given by starting upstream of the electrolyser 1 and following the direction of circulation in the first supply line 2.

Preferably, the first supply line 2 provides the fluid connection, for example to a three-way valve 38 connecting the main section 36 and the depression section 35. In the main section 36, the first supply line 2 provides the fluid connection to the steam generators arranged in series, in particular possibly from the seventh steam generator 42 to the fifth steam generator 24, then from the fifth steam generator 24 to the third steam generator 20, then from the third steam generator 20 to the first steam generator 6 , then from the first steam generator 6 to a three-way valve 41. In the depression section 35, the first supply line 2 provides the fluidic connection to an expansion valve 8, then preferably from the expansion valve 8 to a three-way valve 39 fluidically connecting two parallel branches, one of which ensures the fluidic connection between the vacuum steam generators arranged in series, in particular even from the eighth steam generator 43 to the sixth steam generator 25, from the sixth steam generator 25 to the fourth steam generator 21, then from the fourth steam generator 21 to the second steam generator 7, then from the second steam generator 7 to a three-way valve 40. The three-way valve 39 preferably fluidically connects another parallel branch ensuring the fluidic connection to the condenser 16, then from the condenser 16 to the three-way valve 40. The 2 parallel branches of the depression section 35 meet at the level a three-way valve 40 ensuring the fluidic connection with a compressor 9 terminating the depression section 35. The first supply line 2 provides the fluidic connection of the compressor 9 to a three-way valve 41 connected to the main section 36 of the first supply line 2. The first supply line 2 then ensures the fluidic connection of the three-way valve 41 to the heater 15, then of the heater 15 to the first heat exchange module 5, preferably to the first heat exchanger 5a, then the fluid connection of the first heat exchanger 5a to the second heat exchanger 5b, then the fluid connection of the second heat exchanger 5b to the electric heater 14, then the connection fluid from electric heater 14 to electrolyser 1.

Preferably, the electrolyser 1 is fluidically connected to a first evacuation line 4 of dihydrogen. The first evacuation line 4 ensures the fluidic connection of components arranged downstream of the electrolyser 1 on said first evacuation line 4. The following description is made starting from the electrolyser 1 and following the direction of circulation in the first evacuation line 4 from the electrolyser 1.

The first evacuation line 4 ensures the fluid connection of the electrolyzer 1 with the first heat exchange module 5, more preferably with the second heat exchanger 5b, then the fluid connection of the second heat exchanger 5b to the first heat exchanger 5a, then the fluid connection of the first heat exchanger 5a to the first steam generator 6, then from the first steam generator 6 to the second vacuum steam generator 7, then from the second vacuum steam generator 7 to the first treatment stage 44, more precisely to the evaporator 17, then from the evaporator 17 to the liquid/gas separator 18, then from the liquid/gas separator 18 to the second treatment stage 45, more precisely to the compressor 19, then from the compressor 19 to the air cooler 20, then from the air cooler 20 to the third steam generator 21, then from the third steam generator 21 to the fourth vacuum steam generator 22, then from the fourth generator of steam in depression 22 to the compressor 23, then from the compressor 23 to the fifth steam generator 24, then from the fifth steam generator 24 to the sixth steam generator in depression 25, then from the sixth steam generator in depression 25 to the third stage of treatment 46, more precisely to the air cooler 26, then from the air cooler 26 to the heat exchanger 27 then from the heat exchanger 27 to the liquid/gas separator 28, then from the liquid/gas separator 28 to the storage of the dihydrogen.

Preferably, the electrolyser 1 is fluidically connected to a second evacuation line 3 of dioxygen. The second evacuation line 3 ensures the fluidic connection of components arranged downstream of the electrolyser 1 on said second evacuation line 3. The following description is made starting from the electrolyser 1 and following the direction of circulation in the second evacuation line 3 from the electrolyser 1.

The second evacuation line 3 ensures the fluidic connection of the electrolyser 1 with the second heat exchange module 11, more preferably with the second heat exchanger 11b, then the fluidic connection of the second heat exchanger 11b to the first heat exchanger 11a. The output of the first heat exchanger 11a is fluidically connected to an exchanger train, more precisely a steam generator 42, more precisely a seventh steam generator 42, then the second evacuation line 3 ensures the fluidic connection of the seventh steam generator. steam 42 to the eighth steam generator 43 in depression, then the outlet of the oxygen from said steam generator 43.

Preferably, the electrolyser 1 is fluidically connected to the second air supply line 10. The second supply line 10 ensures the fluidic connection of components arranged upstream of the electrolyser 1 on said second supply line 10. The second supply line ensures the fluidic connection of the compressor 12 to the first heat exchanger 11a, then the fluidic connection of the first heat exchanger 11a to the second heat exchanger 11b, then the fluidic connection of the second heat exchanger 11b to the electric heater 13, then the fluidic connection of the electric heater 13 to the electrolyser 1.

The system includes fluidic connections described below and forming part of the various supply lines 2, 10 and evacuation lines 3, 4 of the system.

Regarding the first supply line 2, it advantageously comprises a fluidic connection A connected to the inlet of the three-way valve 38.

Advantageously, the first supply line 2 comprises a fluidic connection B connected between the outlet of the three-way valve 38 and the inlet of a steam generator, for example the first steam generator 6 in or the fifth steam generator 24 in or even in a manner not shown the seventh steam generator 42.

Advantageously, the first supply line 2 comprises a fluidic connection B′ connected between the outlet of a steam generator, for example the first steam generator 6 in or the fifth steam generator 24 in or even in a manner not shown the seventh steam generator 42 and the inlet of a steam generator, for example the third steam generator 20 in .

Advantageously, the first supply line 2 comprises a fluidic connection C connected between the outlet of a steam generator, preferably the first steam generator 6 and the three-way valve 41.

Advantageously, the first supply line 2 comprises a fluidic connection D connected between the outlet of the three-way valve 38 and the inlet of the regulator 8.

Advantageously, the first supply line 2 comprises a fluidic connection E connected between the outlet of the expander 8 and the inlet of a steam generator under depression, for example the second steam generator 7 in or the sixth steam generator 25 in or even in a manner not shown the eighth steam generator 43.

Advantageously, the first supply line 2 comprises a fluidic connection E′ connected between the outlet of the steam generator under vacuum, for example the second steam generator 7 under or the sixth steam generator 25 in or alternatively, in a manner not shown, the eighth steam generator 43 and the inlet of a vacuum steam generator, for example the fourth steam generator as shown in or the sixth steam generator as not shown.

Advantageously, the first supply line 2 comprises a fluidic connection E'' connected between the outlet of the steam generator under depression, for example the fourth steam generator as shown in or the sixth steam generator as not shown and the inlet of a vacuum steam generator, for example the second steam generator.

Advantageously, the first supply line 2 comprises a fluidic connection F connected between the outlet of the second vacuum steam generator 7 and the inlet of the compressor 9.

Advantageously, the first supply line 2 comprises a fluidic connection G connected between the outlet of the compressor 9 and the three-way valve 41.

Advantageously, the first supply line 2 comprises a fluidic connection H connected between the outlet of the expander 8 more precisely at the outlet of a three-way valve 39 connected to the fluidic connection E and the inlet of the condenser 16.

Advantageously, the first supply line 2 comprises a fluidic connection I connected between the outlet of the condenser 16 and the inlet of the compressor 9 more precisely, of a three-way valve 40 connected to the fluidic connection F.

Advantageously, the first supply line 2 comprises a fluidic connection J connected between the outlet of the three-way valve 41 and the inlet of the heater 15.

Advantageously, the first supply line 2 comprises a fluidic connection K connected between the outlet of the heater 15 and the inlet of the first heat exchanger 5a of the heat exchange module 5.

Advantageously, the first supply line 2 comprises a fluidic connection L connected between the outlet of the first heat exchanger 5a and the inlet of the second heat exchanger 5b.

Advantageously, the first supply line 2 comprises a fluidic connection M connected between the outlet of the second heat exchanger 5b and the inlet of the electric heater 14.

Advantageously, the first supply line 2 comprises a fluidic connection N connected between the output of the electric heater 14 and the input of the electrolyser 1.

Regarding the first evacuation line 4, it advantageously comprises a first fluidic connection 200 between the outlet of the electrolyser 1 and the inlet of the second heat exchanger 5b of the first heat exchange module 5.

Advantageously, the first evacuation line 4 comprises a fluidic connection 201 between the outlet of the second heat exchanger 5b of the first heat exchange module 5 and the inlet of the first heat exchanger 5a of the first heat exchange module 5.

Advantageously, the first evacuation line 4 comprises a fluidic connection 202 between the outlet of the first heat exchanger 5a and the inlet of the first steam generator 6.

Advantageously, the first evacuation line 4 comprises a fluidic connection 202 between the outlet of the first heat exchanger 5a and the inlet of the first steam generator 6.

Advantageously, the first evacuation line 4 comprises a fluidic connection 202 between the outlet of the first heat exchanger 5a and the inlet of the first steam generator 6.

Advantageously, the first evacuation line 4 comprises a fluidic connection 202 between the outlet of the first heat exchanger 5a and the inlet of the first steam generator 6.

Advantageously, the first evacuation line 4 comprises a fluidic connection 203 between the outlet of the first steam generator 6 and the inlet of the second steam generator 7.

Advantageously, the first evacuation line 4 comprises a fluidic connection 204 between the outlet of the second steam generator 7 and the inlet of the evaporator 17.

Advantageously, the first evacuation line 4 comprises a fluid connection 205 between the outlet of the evaporator 17 and the inlet of the liquid/gas separator 18.

Advantageously, the first evacuation line 4 comprises a fluidic connection 206 between the outlet of the liquid/gas separator 18 and the inlet of the compressor 19.

Advantageously, the first evacuation line 4 comprises a fluidic connection 207 between the outlet of the compressor 19 and the inlet of the third steam generator 20.

Advantageously, the first evacuation line 4 comprises a fluidic connection 208 between the outlet of the third steam generator 20 and the inlet of the fourth steam generator 21.

Advantageously, the first evacuation line 4 comprises a fluidic connection 209 between the outlet of the fourth steam generator 21 and the inlet of the air cooler 22.

Advantageously, the first evacuation line 4 comprises a fluidic connection 210 between the outlet of the air cooler 22 and the inlet of the compressor 23.

Advantageously, the first evacuation line 4 comprises a fluidic connection 211 between the outlet of the compressor 23 and the inlet of the fifth steam generator 24.

Advantageously, the first evacuation line 4 comprises a fluid connection 212 between the outlet of the fifth steam generator 24 and the inlet of the sixth steam generator 25.

Advantageously, the first evacuation line 4 comprises a fluidic connection 213 between the outlet of the sixth steam generator 25 and the inlet of the air cooler 26.

Advantageously, the first evacuation line 4 comprises a fluidic connection 214 between the outlet of the air cooler 26 and the inlet of the heat exchanger 27.

Advantageously, the first evacuation line 4 comprises a fluidic connection 215 between the outlet of the heat exchanger 27 and the inlet of the separator 28.

Advantageously, the first evacuation line 4 comprises a fluidic connection 216 ensuring the output of dihydrogen from the separator 28.

Regarding the second evacuation line 3 of dioxygen, it advantageously comprises a fluidic connection 100 between the outlet of the electrolyser 1 and the inlet of the second heat exchanger 11b of the second heat exchange module 11.

Advantageously, the second evacuation line 3 comprises a fluidic connection 101 between the outlet of the second heat exchanger 11b and the inlet of the first heat exchanger 11a of the second heat exchange module 11.

Advantageously, the second evacuation line 3 comprises a fluidic connection 102 between the outlet of the first heat exchanger 11a and the inlet to an exchanger train, more precisely to the inlet of the seventh steam generator 42.

Advantageously, the second evacuation line 3 comprises a fluidic connection 103 between the outlet of the seventh steam generator 42 and the inlet of the eighth steam generator 43.

Advantageously, the second evacuation line 3 comprises a fluidic connection 104 between the outlet of the eighth steam generator 43 and the outside.

Regarding the second air supply line 10, it advantageously comprises a fluidic connection 110 entering the compressor 12.

Advantageously, the second supply line 10 comprises a fluidic connection 111 between the outlet of the compressor 12 and the inlet of the first heat exchanger 11a of the second heat exchange module 11.

Advantageously, the second supply line 10 comprises a fluidic connection 112 between the outlet of the first heat exchanger 11a and the inlet of the second heat exchanger 11b of the second heat exchange module 11.

Advantageously, the second supply line 10 comprises a fluidic connection 113 between the outlet of the second heat exchanger 11b and the inlet of the electric heater 13.

Advantageously, the second supply line 10Keita en comprises a fluidic connection 114 between the outlet of the electric heater 13 and the inlet of the electrolyser 1.

In operation, liquid water arrives in the first steam supply line 2. The liquid water may come from the water recycling line 33 and/or from an external water supply 34.

The fluid connection A is advantageously connected to the inlet of the three-way valve 38. The three-way valve 38 is fluidly connected to the main section 36 and to the depression section 35. The three-way valve 38 is fluidly connected to the main section 36 by the fluidic connection B opening out at the inlet of the first steam generator 6. In the first steam generator 6, the liquid water recovers thermal energy supplied by the dihydrogen flowing in the first evacuation line 4. Preferably, the liquid water leaves the first steam generator 6 in the vapor state via the fluidic connection C and emerges, preferably directly, into the three-way valve 41. The three-way valve 38 is fluidically connected to the depression section 35 by the fluidic connection D emerging at the inlet of the regulator 8. The regulator 8 makes it possible to lower the pressure in the first supply line 2 downstream of the regulator 8. The liquid water leaves the det endeur 8 in depression through the fluidic connection E and preferably penetrates directly into the second steam generator in depression 7. In the second steam generator in depression 7, the liquid water in depression is heated by the thermal energy of the dihydrogen circulating in the first evacuation line 4. Preferably, the liquid water leaves the second steam generator under depression, it is in the gaseous state through the fluidic connection F and enters, preferably directly into the compressor 9. In the compressor 9, the water vapor in depression is compressed to reach the pressure of the main section 36. The compressed water vapor leaves the compressor 9 through the fluidic connection G opening into the three-way valve 41. Preferably, the liquid water leaving the pressure reducer 8 in depression by the fluidic connection E, in a three-way valve 39 fluidically connected to the inlet of the second steam generator 7 by the fluidic connection E and at the inlet of the condenser 16 by the fluidic connection H. In the condenser 16, the liquid water in depression is heated by the thermal energy of the heat transfer fluid of the heat pump recovered by the evaporator 17 on the dihydrogen circulating in the first evacuation line 4. At the outlet of the condenser 17, the water is advantageously in the vapor state and exits through the fluidic connection connected thereto preferably by the three-way valve 40 fluidically connected to the fluidic connection F in upstream of the compressor 9. The water in the vapor state leaves the three-way valve 41 through the fluidic connection J and enters, preferably directly into a heater 15. The water in the vapor state will possibly be heated by the heater 15 to reach a target temperature. The water vapor leaves heater 15 via fluidic connection K and preferably enters directly into first heat exchange module 5, preferably into first heat exchanger 5a. The water vapor is heated in the first heat exchanger 5a by recovering calories from the dihydrogen circulating in the first heat exchanger 5a. The superheated water vapor leaves the first heat exchanger 5a via the fluid connection L and enters, preferably directly, into the second heat exchanger 5b. The water vapor is again heated in the second heat exchanger 5b by recovering calories from the dihydrogen circulating in the second heat exchanger 5b. The superheated water vapor leaves the second heat exchanger 5b via the fluidic connection M and enters, preferably directly, into the electric heater 14 if necessary. The electric heater 14 provides the last rise in temperature that may be necessary for the water vapor to reach a predefined target temperature to enter the electrolyser 1. The water vapor leaves the electric heater 14 through the fluidic connection N and enters, preferably directly, in the electrolyser 1.

According to an embodiment illustrated in , the main section 36 is fluidically connected to the three-way valve 38 by the fluidic connection B opening out at the inlet of the fifth steam generator 24. In the fifth steam generator 24, the liquid water recovers thermal energy supplied by the dihydrogen flowing in the first evacuation line 4. Preferably, the liquid water leaves the fifth steam generator 24 heated or possibly in the vapor state through the fluidic connection B′ and emerges, preferably directly, into the third steam generator 20, in which the liquid water optionally heated in the vapor state recovers thermal energy provided by the dihydrogen flowing in the first evacuation line 4. Preferably, the liquid water leaves the third generator of vapor 20 heated or possibly in the vapor state by the fluidic connection B'' and emerges, preferably directly, into the first steam generator 6, into the which the liquid water possibly heated in the vapor state recovers thermal energy supplied by the dihydrogen circulating in the first evacuation line 4. In the first steam generator 6, the liquid water recovers energy heat provided by the dihydrogen flowing in the first evacuation line 4. Preferably, the liquid water leaves the first steam generator 6 in the vapor state through the fluidic connection C and opens, preferably directly, into the three-way valve 41.

According to an embodiment illustrated in , the three-way valve 38 is fluidically connected to the depression section 35 by the fluidic connection D opening out at the inlet of the regulator 8. The regulator 8 makes it possible to lower the pressure in the first supply line 2 downstream of the regulator 8. The liquid water leaves the pressure reducer 8 in depression through the fluidic connection E and preferably enters directly into the sixth steam generator in depression 25. In the sixth steam generator in depression 25, the liquid water in depression is heated by the thermal energy of the dihydrogen circulating in the first evacuation line 4. Preferably, the liquid water leaves the sixth steam generator under depression, that is to say in the gaseous state through the fluidic connection F′ and enters, preferably directly into the fourth vacuum steam generator 24. In the fourth vacuum steam generator 24, the liquid or vapor water under vacuum is heated by thermal energy dihydrogen circulating in the first evacuation line 4. preferentially, the liquid water leaves the fourth steam generator in depression it is in the gaseous state through the fluidic connection F'' and penetrates, preferentially directly into the second generator of steam in depression 7. In the second steam generator in depression 7, the liquid water in depression is heated by the thermal energy of the dihydrogen circulating in the first evacuation line 4. Preferably, the liquid water leaves the second steam generator in depression, that is to say in the gaseous state through the fluidic connection F and penetrates, preferably directly into the compressor 9. In the compressor 9, the water vapor in depression is compressed to reach the pressure of the main section 36. The compressed water vapor leaves the compressor 9 through the fluidic connection G opening into the three-way valve 41. In the same way as in FIGS. 1 and 3, preferably the water liquid leaving the expander 8 under vacuum through the fluidic connection E, in a three-way valve 39 fluidically connected to the inlet of the 2nd steam generator 7 by the fluidic connection E and to the inlet of the condenser 16 by the fluidic connection H. In the condenser 16, the liquid water in depression is heated by the thermal energy of the heat transfer fluid of the heat pump recovered by the evaporator 17 on the dihydrogen circulating in the first evacuation line 4. At the outlet of the condenser 17 , the water is advantageously in the vapor state and exits through the fluidic connection I preferably connected by the three-way valve 40 to the fluidic connection F upstream of the compressor 9.

The electrolyser 1 is supplied with electric current according to a voltage and a predefined intensity making it possible to ensure the electrolysis and therefore the production of dihydrogen and dioxygen.

The dihydrogen leaves the electrolyser 1 via the first evacuation line 4, via the fluidic connection 200 and penetrates, preferably directly, into the first heat exchange module 5, preferably the second heat exchanger 5b. The dihydrogen leaves the electrolyser in the hot gaseous state, it is necessary to lower its temperature to use it and/or store it. The calories of the dihydrogen are therefore recovered by the first supply line and more precisely the water or the steam circulating therein. In the second heat exchanger 5b, the dihydrogen sees its temperature lowered by transfer of calories to the benefit of the water vapor circulating in the second heat exchanger 5b. The cooled dihydrogen leaves the second heat exchanger 5b through the fluidic connection 201 and enters, preferably directly, into the first heat exchanger 5a. In the first heat exchanger 5a, the dihydrogen again sees its temperature lowered by transfer of calories to the benefit of the water vapor circulating in the first heat exchanger 5a. The cooled dihydrogen leaves the first heat exchanger 5a through the fluidic connection 202 and enters, preferably directly, into the evaporator 17. By passing through the evaporator 17, the dihydrogen is cooled in favor of the heat transfer fluid circulating in the fluidic circuit 31 of the heat pump which will transfer this thermal energy in favor of the water or steam circulating in the first supply line 2, preferably at the level of the condenser 16 preferably arranged on the depression section 35. The dihydrogen comes out of the evaporator 17 via the fluidic connection 205 and penetrates, preferably directly, into the separator 18 ensuring the condensation of the water contained in the dihydrogen. The dihydrogen leaves the liquid/gas separator 18 via the fluidic connection 206 and preferentially enters directly into the compressor 19. The dihydrogen is compressed and sees its pressure increase. The dihydrogen leaves the compressor 19 through the fluidic connection 207 and preferentially penetrates directly into the third steam generator 20 where it undergoes cooling in favor of the water, or steam, circulating in the first supply line 2 , preferably in the main section 36. The cooled dihydrogen leaves the third steam generator 20 through the fluidic connection 208 and enters, preferably directly, into the fourth vacuum steam generator 21. In the fourth vacuum steam generator 21, the dihydrogen is again cooled in favor of the water, or steam, flowing in the first supply line 2, preferably in the section under depression 35. The dihydrogen leaves the fourth steam generator under depression 21 by the fluidic connection 209 and penetrates, preferably directly, into the air cooler 22 ensuring the condensation of part of the water vapor contained naked in dihydrogen. The dihydrogen, preferably the gaseous dihydrogen, water vapour, condensed liquid water mixture leaves the air cooler 22 via the fluidic connection 210 and penetrates, preferably directly, into the compressor 23 and undergoes compression with a view to further condensation. The dihydrogen leaves the compressor 23 through the fluidic connection 211 and preferably enters directly into the fifth steam generator 24. In the fifth steam generator 24, the dihydrogen is cooled by heat transfer to the benefit of water, steam water, circulating in the first supply line 2, preferably in the main section 36. The dihydrogen cooler of the fifth steam generator 24 via the fluidic connection 212 and penetrates, preferably directly, into the sixth vacuum steam generator 25. In the sixth vacuum steam generator 25, the dihydrogen is cooled in favor of heat transfer to the water, or steam, flowing in the first supply line 2, more precisely in the vacuum section 35. The dihydrogen cooled leaves the sixth and enters, preferably directly, the air cooler 26 or a heat exchanger ensuring the cooling of u dihydrogen. The dihydrogen leaves the air cooler 26 or a heat exchanger through the fluidic connection 214 and penetrates, preferably directly, into the liquid/gas separator 28 ensuring the condensation of the dihydrogen. According to one possibility shown, the dihydrogen leaves the air cooler 26 through the connection 214 and enters, preferably directly, into a heat exchanger 27. Then, the dihydrogen again cooled by the heat exchanger exits through the fluidic connection 115 and enters, preferably directly, in the separator 28. The condensed dihydrogen leaves the liquid/gas separator 28 through the fluidic connection 216 and can be used or stored. The condensed liquid water recovered from the liquid/gas separator 18, 28 can be recycled into the first steam supply line 2 by fluidic connection with the water recycling line 33.

The oxygen produced by the electrolyser exits through the second evacuation line 3, through the fluidic connection 100 and penetrates, preferably directly, into the second heat exchange module 11, preferably the second heat exchanger 11b. The oxygen comes out of the electrolyser in a hot gaseous state, it is necessary to lower its temperature for discharge into the air. The calories of the dioxygen are therefore advantageously recovered by the second supply line 10 and more precisely the air circulating therein. In the second heat exchanger 11b, the oxygen sees its temperature lowered by transfer of calories to the benefit of the air circulating in the second heat exchanger 11b. The cooled oxygen leaves the second heat exchanger 11b through the fluidic connection 101 and enters, preferably directly, into the first heat exchanger 11a. In the first heat exchanger 11a, the oxygen again sees its temperature lowered by transfer of heat to the benefit of the air circulating in the first heat exchanger 11a. The cooled oxygen leaves the first heat exchanger 11a via the fluidic connection 102 and enters, preferably directly, the seventh steam generator 42. In the seventh steam generator 42, the oxygen transfers its thermal energy to the benefit of the water, or steam, circulating in the first supply line 2. The cooled oxygen leaves the seventh steam generator 42 and enters, preferably directly, into the eighth steam generator under vacuum 43. In the eighth steam generator under vacuum 43 , the oxygen transfers its thermal energy to the benefit of the water, or steam, circulating in the first supply line of, more precisely in the depression section 35. The cooled oxygen leaves the eighth steam generator 43 and is released into the air.

According to one possibility, air is supplied to the electrolyser 1. The air arrives via the second supply line 10 via the fluid connection 110 and enters, preferably directly, into the compressor 12. The air is compressed by the compressor 12 and its temperature increases. The air leaves compressor 12 via fluidic connection 111 and enters, preferably directly, into second heat exchange module 11, preferably into first heat exchanger 11a. The air is heated in the first heat exchanger 11a by recovering calories from the oxygen circulating in the first heat exchanger 11a. The superheated air leaves the first heat exchanger 11a through the fluid connection 112 and enters, preferably directly, into the second heat exchanger 11b. The air is again heated in the second heat exchanger 11b by recovering calories from the oxygen circulating in the second heat exchanger 11b. The superheated air leaves the second heat exchanger 11b via the fluidic connection 113 and enters, preferably directly, into the electric heater 13 if necessary. The electric heater 13 provides the last rise in temperature that may be necessary for the air to reach a predefined target temperature to enter the electrolyser 1. The air leaves the electric heater 13 through the fluidic connection 114 and enters, preferably directly, into electrolyser 1.

The invention is not limited to the embodiments previously described and extends to all the embodiments covered by the invention.

LIST OF REFERENCES
1 electrolyser
2 water vapor supply line
3 oxygen evacuation line
4 dihydrogen evacuation line
5a first heat exchanger of the first heat exchange module
5b second heat exchanger of the first heat exchange module
6 first steam generator
7 second steam generator
9 compressor
10 air supply line
11a first heat exchanger of the second heat exchange module
11b second heat exchanger of the second heat exchange module
12 compressor
13 electric heater
14 electric heater
15 electric heater
16 condenser
17 evaporator
17a evaporator
17b evaporator
18 liquid/gas separator
19 compressor
20 third steam generator
21 fourth steam generator
22 air cooler
23 compressor
24 fifth steam generator
25 sixth steam generator
26 air cooler
27 heat exchanger
28 liquid/gas separator
29 compressor
29a compressor
29b compressor
30 regulator
30a regulator
30b regulator
31 fluid circuit
32 heat exchanger
33 water recycling line
34 external water
35 section in depression
36 main section
37 three-way valve
38 three way valve
39 three way valve
40 three-way valve
41 three-way valve
42 seventh steam generator
43 eighth steam generator
With fluidic connection receiving recycling water and external water
B fluid connection between the three-way valve 38 and the first steam generator 6
C fluidic connection between the first steam generator and the three-way valve 41
D fluidic connection between the three-way valve 38 and the expansion valve 8
E fluidic connection between the expansion valve 8 and the second steam generator 7
F fluidic connection between the second steam generator 7 and the compressor 9
G fluid connection between compressor 9 and three-way valve 41
H fluid connection between the three-way valve 39 and the condenser 16.
I fluidic connection between the condenser 16 and the three-way valve 40
J fluid connection between the three-way valve 41 and the electric heater 15
K fluid connection between the electric heater 15 and the first heat exchanger 5a
The fluid connection between the first heat exchanger 5a and the second heat exchanger 5b
M fluid connection between the second heat exchanger 5b and the heater 14
N fluidic connection between the heater 14 and the electrolyser 1
100 fluidic connection between the electrolyser 1 and the second heat exchanger 11b
101 fluid connection between the second heat exchanger 11b and the first heat exchanger 11a
102 fluidic connection between the first heat exchanger 11a and the seventh steam generator 42
103 fluidic connection between the 7th steam generator 42 and the 8th steam generator 43
104 eighth steam generator outlet fluidic connection 43
110 inlet fluidic connection in the compressor 12
111 fluid connection between the compressor 12 and the first heat exchanger 11a
112 fluid connection between the first heat exchanger 11a and the second heat exchanger 11b
113 fluidic connection between the second heat exchanger 11b and the heater 13
114 fluid connection between heater 13 and electrolyser 1
200 fluidic connection between the electrolyser 1 and the second heat exchanger 5b
201 fluid connection between the second heat exchanger 5b and the first heat exchanger 5a
202 fluidic connection between the first heat exchanger 5a and the first steam generator 6
203 fluidic connection between the first steam generator 6 and the 2nd steam generator 7
204 fluidic connection between the second steam generator 7 and the evaporator 17
205 fluidic connection between the evaporator 17 and the liquid/gas separator 18
206 fluidic connection between the liquid/gas separator 18 and the fluidic compressor 19
207 fluidic connection between the compressor 19 and the third steam generator 20
208 fluidic connection between the 3rd steam generator 20 and the fourth steam generator 21
209 fluidic connection between the 4th steam generator 21 and the air cooler 22
210 fluidic connection between the air cooler 22 and the compressor 23
211 fluidic connection between the compressor 23 and the fifth steam generator 24
212 fluidic connection between the fifth steam generator 24 and the sixth steam generator 25
213 fluidic connection between the sixth steam generator 25 and coolers 26
214 fluidic connection between the air cooler 26 and the heat exchanger 27
215 fluidic connection between the heat exchanger 27 and the liquid/gas separator 28
216 liquid/gas separator dihydrogen outlet fluid connection 28
300 fluid connection between compressor 29 and condenser 16
301 fluid connection between condenser 16 and expansion valve 30
302 fluidic connection between the expansion valve 30 and the evaporator 17
303 fluid connection between evaporator 17 and compressor 29

Claims (13)

System including

• a high temperature (EHT) electrolyser (1),
• a first supply line (2) of the electrolyser configured to supply the electrolyser (1) with steam,
• a first evacuation line (4) of the electrolyser configured to evacuate dihydrogen from the electrolyser (1),
• a second exhaust line (3) of the electrolyser configured to evacuate dioxygen from the electrolyser (1),
• a first steam generator (6) arranged on the first steam supply line (2), and configured to produce steam from liquid water,

Characterized in that

• the first water vapor supply line (2) of the electrolyser comprises a main section (36) and a depression section (35),
• the system comprises a module for creating a vacuum in the vacuum section (35) of the first supply line (2), the module comprising a pressure reducer (8) and a compressor (9),
• the system comprises a second vacuum steam generator (7) arranged on the vacuum section (35) between the expander (8) and the compressor (9),
• the first steam generator (6) and the second steam generator (7) are heat exchangers also arranged on the first evacuation line (4) of the dihydrogen, the first steam generator (6) being arranged upstream of the second steam generator (7) relative to the first evacuation line (4) of the dihydrogen.

System according to the preceding claim comprising a third steam generator (20) arranged on the first steam supply line (2), upstream of the first steam generator (6) and on the first evacuation line ( 4) dihydrogen downstream of the second steam generator (7) configured to produce steam from liquid water. System according to the preceding claim comprising a fourth steam generator (21) arranged on the depression section (35) of the first steam supply line (2), upstream of the second steam generator (7) and on the first evacuation line (4) of the dihydrogen downstream of the third steam generator (20) configured to produce steam from liquid water. System according to any one of the two preceding claims, comprising a fifth steam generator (24) arranged on the first steam supply line (2), upstream of the third steam generator (20) and on the first evacuation line (4) of the dihydrogen downstream of the fourth steam generator (21) configured to produce steam from liquid water. System according to any one of the three preceding claims, comprising a sixth steam generator (25) arranged on the depression section (35) of the first steam supply line (2), upstream of the fourth steam generator. steam (21) and on the first evacuation line (4) of the dihydrogen downstream of the fifth steam generator (24) configured to produce steam from liquid water. System according to any one of the preceding claims, comprising a first heat exchange module (5) configured to ensure a heat exchange between the first steam supply line (2) and the first evacuation line (4 ) dihydrogen, the first heat exchange module (5) being arranged on the first steam supply line (2) downstream of the steam generators and on the first evacuation line (4) for the dihydrogen upstream of the steam generators. System according to the preceding claim comprising a heater (15) arranged on the first steam supply line (2) upstream of the first heat exchange module (5) and downstream of the steam generators. System according to any one of the preceding claims, comprising a seventh steam generator (42) arranged on the first steam supply line (2), upstream of the first steam generator (6) and on the second discharge line (3) of the electrolyser configured to discharge from the electrolyser (1) oxygen configured to produce water vapor from liquid water. System according to the preceding claim comprising an eighth steam generator (43) arranged on the depression section of the first steam supply line (2), upstream of the second steam generator (7) and on the second discharge line (3) of the electrolyser configured to discharge from the electrolyser (1) oxygen downstream of the seventh steam generator (42) configured to produce steam from liquid water. System according to any one of the preceding claims comprising at least a liquid/gas separator (18) arranged on the first dihydrogen evacuation line (4) downstream of the steam generators. System according to any one of the preceding claims, in which the water circulating in the main section (36) and/or in the depression section (35) is at least partly water resulting from the drying out of the dihydrogen by a liquid/gas separator (18) arranged on the first evacuation line (4) of dihydrogen, for example downstream of the steam generators. System according to any one of the preceding claims, comprising a module for recovering thermal energy from dihydrogen for the benefit of the first steam supply line (2), the recovery module comprising a heat pump comprising

• a fluidic circuit (31) configured to receive a heat transfer fluid,
• an evaporator (17) arranged on the first evacuation line (4) downstream of the second steam generator (7) on the depression section (35), configured to transfer the thermal energy from the dihydrogen to the heat transfer fluid,
• a compressor (29) configured to compress the heat transfer fluid,
• a condenser (16) arranged on the first steam supply line (2) on the depression section (35) in parallel to the second steam generator (7), configured to transfer the thermal energy of the heat transfer fluid with liquid water,
• an expander (30) configured to expand the heat transfer fluid,
• the fluidic circuit (31) being configured to fluidically connect the evaporator (17) to the compressor (29), the compressor (29) to the condenser (16), the condenser (16) to the expander (30) and the expander (30) to the evaporator (17).

System according to the preceding claim, in which the heat pump comprises an additional evaporator (17b) configured to take calories from an external source, the additional evaporator (17b) being arranged in parallel with the evaporator (17).
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