Supply system for replenishing electrolysis unit and related equipment and method

Abstract

To provide an efficiently energy-reduced electrolyte solution supply system and equipment for dihydrogen and dioxygen production, and a method for replenishing an electrolyte replenishment flow.SOLUTION: A supply system 14 includes an electrolyte reservoir 30 configured to store an electrolyte solution and a circulation unit 32 for circulating the electrolyte solution stored in the electrolyte reservoir to an electrolyte recovery outlet 36. The circulation unit includes an osmosis unit 40 that is equipped with a movable actuator 42 configured to cause displacement of the electrolyte solution within the electrolyte reservoir, a first chamber 44 fluidly connected to a first supply source of a low salinity solution, a second chamber 46 fluidly connected to a second supply source of a high salinity solution, and a semipermeable membrane 48 separating the first and second chambers. The osmosis unit is configured to actuate the actuator by an osmosis phenomenon between the first and second chambers.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a supply system for replenishing an electrolyte make-up stream to an electrolysis unit.

[0002] The invention also relates to an installation comprising such a supply system, in particular in an electrochemical installation for the production of dihydrogen from water electrolysis, for electrochemical CO reduction, for electrochemical N reduction or for chlor-alkali electrolysis, as well as a method for supplying an electrolyte make-up stream to an electrolysis unit. [Background technology]

[0003] Water electrolysers are used to produce dihydrogen and dioxygen by passing an electric current through an aqueous electrolyte to electrochemically convert water into dihydrogen and dioxygen.

[0004] Existing systems, for example, include a stack of electrochemical cells, in which dihydrogen is produced at a cathode separated by a membrane from an anode where dioxygen is produced.

[0005] Other systems are based on membrane-less cells that require a specific cell / stack architecture, for example in a flow electrolyser cell, it is essentially the flow rate of the incoming water that makes it possible to separate the gases produced on the electrodes located on each side of the water channel.

[0006] Although water electrolysis has been significantly optimized during the 20th century, the amount of hydrogen produced by this method remains very low (4% of global hydrogen production) compared to hydrogen produced from fossil fuels, mainly via steam methane reforming (grey hydrogen), which accounts for 96% of global hydrogen production.

[0007] The main factor influencing the cost of hydrogen produced by electrolysis is the cost of electricity, which can represent up to 80% of the cost. The deployment of large renewable energy farms (e.g. solar and / or wind farms) being built or planned in particularly sunny and / or windy regions of the world makes it possible to dramatically reduce the cost of electricity and to facilitate the development of large electrolyzer plants based on multiple stacks. This will pave the way for the potential mass production of so-called "renewable" or green hydrogen. However, for such plants to be economically viable, production costs need to be as low as possible and electricity consumption must be optimized by improving the overall energy efficiency of the process.

[0008] Furthermore, water is consumed during the production of dihydrogen and dioxygen, so the electrolyte needs to be constantly replenished with water. For large-scale water electrolysis installations, huge amounts of water are required, which must be pumped into the electrolyzer. It is expected that future water electrolysis large-scale plants (GW) will be island plants, which should be located near the sea to facilitate hydrogen transport. On the other hand, such localization would allow the production of water from seawater desalination units. Summary of the Invention [Problem to be solved by the invention]

[0009] It is therefore one of the objects of the present invention to provide an installation, in particular for the production of dihydrogen and dioxygen, which is more efficient and reduces energy consumption. [Means for solving the problem]

[0010] To this end, the subject matter of claim 1 provides a supply system for supplying an electrolyte make-up stream to an electrolysis unit, comprising: - an electrolyte reservoir configured to store an electrolyte solution, the electrolyte reservoir including an electrolyte supply inlet and an electrolyte recovery outlet, the electrolyte reservoir configured to be fluidly connected to the electrolysis unit through the electrolyte fluid recovery outlet; a circulation unit for circulating the electrolyte solution in the electrolyte reservoir between an electrolyte supply inlet and an electrolyte recovery outlet; A delivery system comprising: Circulating units: - a movable actuator configured to cause a displacement of an electrolyte solution in an electrolyte reservoir; and - a permeation unit including a first chamber fluidly coupled to a first source of a low salinity solution, a second chamber fluidly coupled to a second source of a high salinity solution, and a semi-permeable membrane separating the first and second chambers; Including, the permeation unit is configured to actuate the actuator by a permeation phenomenon between the first and second chambers; It's in the supply system.

[0011] The permeation unit generates a water flow that can be converted into mechanical power to create an electrolyte flow at a sufficient rate to replenish the electrolytic cell. No additional pumping device that requires electrical energy is required to replenish the electrolyte to the electrolytic cell. Thus, energy efficiency is greatly improved.

[0012] Furthermore, the supply system according to the invention makes it possible to reduce the salinity of the saltwater discharged in particular from the desalination unit.

[0013] The system according to the invention may comprise one or more of the following features, taken alone or according to any technically feasible combination: - the high salinity solution has a mass concentration of salt at least 1.5 times higher than the mass concentration of salt of the low salinity solution, the mass concentration being measured at atmospheric pressure and 25°C; - The infiltration unit is fluidly coupled to the saltwater disposal system of the desalination unit; - each chamber further includes a respective exhaust outlet; - the actuator is at least partially housed within the permeation unit, in particular within the second chamber, such that permeation between the first and second chambers activates the actuator; - the actuator is at least partially contained within the electrolyte reservoir; - the movable actuator is a piston, and penetration between the first and second chambers displaces the piston along the longitudinal axis; - the movable actuator is a rotor system configured to rotate about an axis of rotation, the rotation of the rotor system being caused by percolation between the first and second chambers; - The semi-permeable membrane is made of a composite polymer-based material.

[0014] The invention also relates to an installation, in particular for the production of dihydrogen and dioxygen by water electrolysis, for electrochemical CO reduction, for electrochemical N reduction or for chlor-alkali electrolysis, which comprises: - an electrolysis unit adapted to receive an electrolyte make-up flow and including an electrolytic cell; - a supply system as described above, This also relates to facilities including:

[0015] The installation according to the invention may comprise one or more of the following features, taken individually or according to any technically feasible combination: - the electrolytic cell is a fluid electrolytic cell; The installation further includes a desalination unit configured to replenish the permeation unit.

[0016] The present invention relates to a method of operation for replenishing an electrolyte make-up stream to an electrolysis unit, comprising the steps of: - providing a supply system as described above; - injecting an electrolyte solution into the electrolyte reservoir; - injecting a low salinity solution into a first chamber of the osmotic unit and a high salinity solution into a second chamber of the osmotic unit such that a salinity gradient exists between the first and second chambers, said salinity gradient creating a flow of water between the first and second chambers, said flow of water actuating an actuator; The present invention also relates to a method comprising the steps of:

[0017] The method according to the invention may comprise one or more of the following features, taken alone or according to any technically feasible combination: - injecting the high salinity solution includes recovering saltwater from a saltwater disposal system of the desalination unit; The method further comprises the step of evacuating the first and second chambers.

[0018] The invention can be better understood on the basis of the following description, given by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0019] [Figure 1] 1 is a schematic flow chart of an installation according to the invention, including a supply system according to the invention; [Diagram 2] FIG. 2 is a schematic diagram of the delivery system of FIG. 1 according to a first embodiment, including a piston shown in an initial position; [Diagram 3] FIG. 3 is a view similar to FIG. 2, with the piston shown in its final position. [Figure 4] FIG. 3 is a view similar to FIG. 2 of a supply system according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] An installation 10 according to the invention, particularly for the production of dihydrogen and dioxygen, is shown in FIG.

[0021] The installation 10 is intended to perform water electrolysis and comprises an electrolysis unit 12 and a supply system 14 intended to supply the electrolysis unit 12 with an electrolyte make-up flow 15 of an electrolyte solution, also called electrolyte.

[0022] Advantageously, the installation 10 further includes a desalination unit 16 configured to produce a purified water stream 17 and a saltwater stream 18 .

[0023] Advantageously, the installation 10 is located close to a water source 19, for example the sea.

[0024] The electrolysis unit 12 is adapted to receive an electrolyte make-up stream 15 .

[0025] In the following description, the electrolysis unit 12 is a unit adapted for producing a dihydrogen and a dioxygen stream by water electrolysis. In a variant, the electrolysis unit 12 is a unit adapted for electrochemical CO reduction, for electrochemical N reduction or for chlor-alkali electrolysis.

[0026] The electrolysis unit 12 comprises an electrolyser 20 (shown in FIG. 2 ) in which the electrochemical reactions take place and a balance of plant coupled to the electrolyser 20, the balance of plant including various fluid handling components to manage the incoming fluids (in particular steam, electricity, air / nitrogen) and outgoing fluids (hydrogen and oxygen).

[0027] The electrolyser 20 includes a number of electrochemical cells 22 assembled in series or parallel to form a stack, with the entire stack being connected to a balance of plant.

[0028] Each cell 22 includes at least two electrodes immersed in an electrolyte. The two electrodes may be separated by one or more separators. The cells 22 are arranged, for example, in a row that defines a stack. One electrode is a negatively charged cathode where dihydrogen is produced, and the other is an anode. By providing water and electricity to the cell, electrolysis of the water occurs.

[0029] As a variant, as shown in the first exemplary embodiment illustrated in Figure 2, the electrolytic cell 20 is a fluid electrolytic cell 20. Said electrolytic cell 20 is based on a membrane-free cell.

[0030] Each cell 22 includes a cathode electrode (not shown), an anode electrode (not shown), a microfluidic channel 24, and a mechanism (not shown) for directing the two generated gases in a direction that facilitates collection of the individual gases.

[0031] The cathode and anode electrodes are positioned proximate the microfluidic channel 24 and allow for the extraction of dihydrogen and dioxygen within the microfluidic channel 24 from the electrolyte solution within the microfluidic channel 24 .

[0032] The cathode and anode electrodes are now separated only by the electrolyte solution within the microfluidic channel 24 .

[0033] The distance between the electrodes is preferably optimized to minimize diffusion of gas across the channel 24, as is known per se.

[0034] The electrolytic cell 20 further includes an electrolyte inlet 25, an electrolyte outlet 26, and at least one dihydrogen mixture outlet and a dioxygen mixture outlet (not shown) for recovering the products of the electrolysis performed in the electrolytic cell 22 of the electrolytic cell 20.

[0035] 2, electrolyte inlet 25 includes a plurality of channel inlets 27 for supplying electrolyte to each channel 24, and electrolyte outlet 26 includes a plurality of channel outlets 28 for withdrawing electrolyte from each channel 24. Electrolyte inlet 25 and outlet 26 are here comb-shaped.

[0036] 2 and 3 show a schematic illustration of a delivery system 14 according to a first embodiment of the invention.

[0037] The supply system 14 is configured to inject the electrolyte solution into the electrolytic cell 20 through the electrolyte inlet 25. The supply system 14 is thus fluidly connected to the electrolytic cell 20 at the electrolyte inlet 25.

[0038] The supply system 14 is adapted to force electrolyte into the electrolyte inlet 25, through each fluid channel 24 and out through the electrolyte outlet 26.

[0039] In a first exemplary embodiment, illustrated in Figures 2 and 3, the supply system 14 is configured to function in a discontinuous mode, which is described in more detail below.

[0040] The supply system 14 comprises an electrolyte reservoir 30 configured to be fluidly connected to the electrolytic cell 20 , and a circulation unit 32 intended to circulate the electrolyte solution stored in the electrolyte reservoir 30 .

[0041] Advantageously, as shown in FIG. 2, the electrolyte reservoir 30 and the circulation unit 32 are disposed within the same container 33.

[0042] The electrolyte reservoir 30 may be, for example, a tank, a pipe system, or any other container suitable for preparing and / or storing a large volume of electrolyte solution. The electrolyte reservoir 30 has an internal volume V 30 Define.

[0043] The electrolyte reservoir 30 defines at least one electrolyte supply inlet 34 and at least one electrolyte return outlet 36 through which it is fluidly connected to the electrolyte flow inlet 25 of the electrolytic cell 20 .

[0044] The electrolyte reservoir 30 is supplied with purified water or electrolyte through an electrolyte supply inlet 34, advantageously by gravity. For example, the electrolyte reservoir 30 is supplied with purified water, the electrolyte being prepared by mixing with a solid or liquid precursor. Advantageously, the electrolyte supply inlet 34 includes a valve 340 which controls the flow rate of the purified water / electrolyte through the electrolyte supply inlet 34.

[0045] The electrolyte can be an alkaline solution, for example a potassium hydroxide solution at a concentration of more than 0.1 mol (0.1M) per liter of electrolyte, preferably more than 1M, more preferably around 6M; or an alkaline hydroxide solution (NaOH, LiOH, CsOH) at a concentration of more than 0.1 mol per liter of electrolyte, preferably more than 1M, or a mixture of solutions of alkaline hydroxides at a concentration of more than 0.1 mol per liter. Additives such as vanadium oxide (VO) at a concentration of more than 1 g per liter can be used. Alternatively, the electrolyte can be an acidic solution or a solution with intermediate pH or pure water.

[0046] Advantageously, the water for the electrolyte solution comes from a purified water stream 17 produced by a desalination unit 16 .

[0047] The circulation unit 32 is configured to circulate the electrolyte solution stored in the electrolyte reservoir 30 to an electrolyte recovery outlet 36 .

[0048] The circulation unit 32 includes a movable actuator 42 and a permeation unit 40 configured to cause displacement of the electrolyte solution within the electrolyte reservoir 30. The movable actuator 42 is disposed at least partially within or in contact with the permeation unit 40.

[0049] The permeation unit 40 includes a first chamber 44 fluidly coupled to a source of a first solution, a second chamber 46 fluidly coupled to a source of a second solution, and a semi-permeable membrane 48 separating the first and second chambers 44, 46.

[0050] 2, each chamber 44, 46 includes at least one respective fluid inlet 50, 52. Advantageously, each fluid inlet 50, 52 includes a valve 500, 520 that controls the flow rate of the first solution or the second solution through the fluid inlet 50, 52.

[0051] Advantageously, as shown in Figure 2, each chamber 44, 46 further includes a respective outlet 54, 56. Advantageously, each outlet 54, 56 includes a valve 540, 560 that controls the flow of the first or second solution through the outlet 54, 56 and out of the first or second chamber 44, 46.

[0052] In the embodiment of FIG. 2, the first chamber 44 is connected through an associated fluid inlet 50 to a source of a first solution (not shown), the first solution being a low salinity solution, while the second chamber 46 is connected through an associated fluid inlet 52 to a source of a second solution (not shown), the second solution being a high salinity solution.

[0053] "High salinity" and "low salinity" solutions refer to aqueous solutions containing inorganic salts, where the salt concentration in the high salinity solution is higher than the salt concentration in the low salinity solution. The salinity gradient between chambers 44, 46 drives the transport of water molecules through membrane 48.

[0054] Advantageously, the low salinity solution is fresh water with a very low concentration of salinity, typically with a total concentration of ions less than 500 mg / L to increase the salinity gradient between the chambers. Alternatively, it may be seawater. The concentration of the low salinity solution is advantageously determined at its entrance into the first chamber 44.

[0055] Advantageously, the hypersaline solution is a very concentrated salt water having a salinity equal to or greater than that of seawater, typically 35 g / L or more. Preferably, the salinity of the hypersaline solution is equal to or up to 10 times greater than that of seawater. The concentration of the hypersaline solution is advantageously determined at an inlet in the second chamber 46.

[0056] Advantageously, the mass concentration of the high-salinity solution is at least 1.5 times higher than the concentration of the low-salinity solution.

[0057] The pressure resulting from the displacement of water molecules through the membrane between the low-salt solution and the high-salt solution (equal to the osmotic pressure) is preferably between 1 bar and 150 bar.

[0058] The aforementioned values ​​of osmolality and mass concentration are determined at 25° C. under atmospheric pressure.

[0059] The low salinity solution is preferably fresh water from a lake or river, or salt water, particularly water from a sea, ocean or lake. As illustrated in Figure 1, the low salinity solution may originate from a water source 19.

[0060] The high salinity solution (also called draw solution) may be, for example, brackish or salt water, particularly derived from desalination unit 16, as described in more detail below.

[0061] The high salinity solution advantageously has an NaCl ion concentration of between 0.4 mol / L (for example in seawater) and 13.2 mol / L (in a saturated solution).

[0062] The NaCl ion concentration of the low-salinity solution is advantageously between 0.1 mmol / L and 0.5 mol / L.

[0063] The semi-permeable membrane 48 forms a separating wall between the first chamber 44 and the second chamber 46. A first side 60, also referred to as the supply side, of the membrane 48 is in contact with the first chamber 44, which contains the low salinity solution. A second side 62 of the membrane 48 is in contact with the second chamber 46, which contains the high salinity solution.

[0064] Advantageously, the semipermeable membrane 48 is a water-selective permeable membrane, typically a molecular sieve made of a composite polymer-based material. For example, the membrane 48 is a thin film composite membrane made of two or more layered materials. The membrane 48 is generally made of a thin polyamide layer, typically having a thickness of less than 200 nm, on a nonwoven support sheet, which is deposited on a polyethersulfone or polysulfone porous layer, typically about 50 microns thick.

[0065] The difference in salinity between the high salinity solution and the low salinity solution leads to an osmotic pressure causing water to permeate through the membrane 48 from the first side 60 to the second side 62 .

[0066] At this time, the salinity of the initial high-saline solution decreases, making it possible to reduce the salinity at the outlet of the second chamber 46 .

[0067] The permeation unit 40 is configured to actuate the actuator 42 by permeation between the first and second chambers 44,46.

[0068] The actuator 42 is configured to use mechanical energy generated by water displacement between the first and second chambers 44, 46 to cause circulation of the electrolyte solution within the electrolyte reservoir 30 by a compression effect.

[0069] Advantageously, the actuator 42 is partly housed within the permeation unit 40 , in particular within the second chamber 44 , and partly housed within the electrolyte reservoir 30 .

[0070] In a first exemplary embodiment illustrated in FIG. 2, the actuator 42 is a piston 70 .

[0071] A piston 70 is engaged within the container 33 between the electrolyte reservoir 30 and the permeate unit 40. A first side 72 of the piston 70 is in contact with the second chamber 46 of the permeate unit 40 and a second side 74 of the piston 70 opposite the first side 72 is in contact with the electrolyte reservoir 30. The piston 70 defines a separation between the second chamber 44 and the electrolyte reservoir 30.

[0072] The piston 70 is configured to move along the longitudinal axis X in response to water displacement within the second chamber 46 .

[0073] The piston 70 is connected to the internal volume V of the electrolyte reservoir 30. 30 is maximum and the volume V of the second chamber 44 46 2 where the internal volume V of the electrolyte reservoir 30 is minimum. 30 is minimum and the volume V of the second chamber 44 46 3, where displacement is at a maximum, along longitudinal axis X. Displacement is represented in the figure by arrow 75A.

[0074] Advantageously, the piston 70 does not include any electrical components.

[0075] When the installation 10 includes a desalination unit 16 , said desalination unit 16 is advantageously configured to replenish the supply system 14 .

[0076] As is known per se, the desalination unit 16 is configured to produce purified water from seawater and to discard salt water.

[0077] Advantageously, purified water produced by desalination unit 16 is used for the electrolyte solution. Purified water stream 17 is conveyed through electrolyte supply inlet 34 to electrolyte reservoir 30.

[0078] The desalination unit 16 further includes a brine disposal system 76 configured to generate a brine stream 18 for the purpose of removing the produced brine.

[0079] Advantageously, the saltwater disposal system 76 is configured to convey at least a portion of the saltwater stream 18 to the supply system 14, and more particularly to the permeation unit 40. In particular, at least a portion of the saltwater stream 18 may be used as a high salinity solution for the second chamber 44. A potential remaining portion of the saltwater stream 18 may be reinjected into the water source 19. The amount of saltwater reinjected into the water source 19 is thus limited and the risk of salinity concentration at the saltwater injection point leading to a large local salinity gradient within the water source 19 is reduced.

[0080] A method of operation of the supply system 14 according to the first embodiment of the invention will now be described, which method is for example implemented in the installation 10 according to the invention.

[0081] Initially, the piston 70 is in its initial position, as shown in FIG.

[0082] The electrolyte reservoir 30 is supplied with electrolyte or purified water through a supply inlet 34. Advantageously, a purified water stream 17 is conveyed from the desalination unit 16 to the electrolyte reservoir 30 through the supply inlet 34 by opening a valve 340.

[0083] Once the electrolyte reservoir 30 is filled, the supply of electrolyte or purified water is stopped, for example, by closing valve 340 .

[0084] The first and second solutions are then injected into the first and second chambers 44, 46 of the permeation unit 40, respectively.

[0085] A low salinity solution is injected into the first chamber 44 and a high salinity solution is injected into the second chamber 46 through the respective fluid inlets 50, 52, for example by opening and then closing the respective valves 500, 520. Advantageously, the step of injecting the high salinity solution includes a preliminary step of recovering salt water from the salt water disposal system 76 of the desalination unit 16.

[0086] Due to the salinity gradient between the low and high salinity solutions, water will flow through the membrane 48 from the first chamber 44 to the second chamber 46 as long as the salinity is different on either side of the membrane 48 .

[0087] Thus, a flow of water is created between the first chamber 44 and the second chamber 46 , activating the movable actuator 42 .

[0088] As can be seen in Figure 2, the accumulation of fluid in second chamber 46 presses against first side 72 of piston 70. Piston 70 is caused to move axially along longitudinal axis X, as shown in Figure 2. The displacement of piston 70 is represented in the figure by arrow 75A.

[0089] The movement of the piston 70 is proportional to the internal volume V 30 The second side 74 of the piston 70 presses against the electrolyte solution in the electrolyte reservoir 30 causing circulation of said solution through the electrolyte recovery outlet 36 and into the electrolytic cell 20.

[0090] The displacement of water molecules through the membrane 48 of the osmotic unit 40 continues until a concentration equilibrium is reached. At that point, the piston 70 stops moving. The piston 70 reaches its final position, depicted in FIG. 3. At this point, the internal volume V of the electrolyte reservoir 30 becomes 30 is minimum, and the volume V of the second chamber 44 46 is the maximum.

[0091] At this point, there is no longer a flow of electrolyte solution between the electrolyte reservoir 30 and the electrolytic cell 20 .

[0092] Advantageously, the salinity gradient between the first and second solutions is selected such that at the end of one stroke of the piston 70, more than 95% of the electrolyte solution originally in the electrolyte reservoir 30 has been delivered to the electrolytic cell 20.

[0093] Advantageously, the method now includes the step of evacuating the first and second chambers 44,46.

[0094] 3, valves 540 and 560 of outlets 54, 56 are opened to allow fluid to flow out of first and second chambers 44, 46 while reservoir 30 is refilled with electrolyte by opening valve 340, leading to displacement of piston 70. In the case of a vertical system configuration, the descent of piston 70 may be driven by gravity.

[0095] The displacement of piston 70 during the ejection step is symbolically represented by arrow 75B in Figure 3. At the end of its stroke, piston 70 returns to its initial position.

[0096] The method can then be repeated.

[0097] The supply system 14 functions in a discontinuous mode in the sense that fluid is not continuously pumped into the electrolyte reservoir 30 or into the permeate unit 40 .

[0098] A second delivery system 114 according to the invention is illustrated diagrammatically in Figure 4. In this figure, components are given reference numbers similar to those of corresponding like components in Figures 2 and 3, but incremented by 100.

[0099] Advantageously, the supply system 114 is configured to operate in a continuous mode, as described in more detail below.

[0100] Similar to the supply system 14 of FIGS. 2 and 3, the supply system 114 of the second embodiment includes an electrolyte reservoir 130 defining at least one electrolyte supply inlet 134 and at least one electrolyte return outlet 136, through which the supply system 114 is fluidly connected to an electrolytic cell (not shown).

[0101] The supply system 114 also includes a circulation device 132 that includes a permeation unit 140 and a movable actuator 142 .

[0102] The permeation unit 140 is similar to the permeation unit 40 according to the first embodiment illustrated in FIGS.

[0103] Advantageously, the second chamber 146 of the permeation unit 140 further includes an additional fluid outlet 178 distinct from the exhaust outlet 156 .

[0104] In one variation, the second chamber 146 does not include an exhaust port 156 .

[0105] In the second embodiment, the movable actuator 142 includes a rotor system 180 disposed at the junction between the electrolyte reservoir 130 and the permeate unit 140 , specifically the second chamber 144 .

[0106] Advantageously, the rotor system 180 does not include any electrical components.

[0107] The rotor system 180 includes a shaft 181 extending through a face plate 182 that separates the electrolyte reservoir 130 from the second chamber 144 such that a first portion 184 of the rotor system 180 is housed within the electrolyte reservoir 130 and a second portion 186 of the rotor system 180 is housed within the second chamber 144.

[0108] Unlike the piston 70 of the first embodiment, the face plate 182 is not movable relative to the container 133, thus allowing the volumes of the electrolyte reservoir 130 and the second chamber 144 to remain constant during operation of the supply system 114.

[0109] 4, the rotor system 180 is illustrated as a double helix system, however, different configurations of the rotor system are possible.

[0110] The rotor system 180 is configured to rotate about an axis of rotation R, and rotation of the rotor system 180 is caused by water displacement between the first and second chambers 142 , 144 of the permeation unit 140 .

[0111] A method of operation of the delivery system 114 according to the second embodiment of the invention will now be described, which method is for example implemented in the installation 10 according to the invention.

[0112] The electrolyte reservoir 130 is supplied with electrolyte solution through an electrolyte supply inlet 134, advantageously by gravity. In a second embodiment illustrated in Figure 4, the electrolyte reservoir 130 can be replenished with electrolyte without a stop phase.

[0113] The first and second solutions are sequentially injected into the first and second chambers 144, 146 of the permeation unit 140, respectively.

[0114] A low salinity solution is injected into the first chamber 144 and a high salinity solution is injected into the second chamber 146 through respective fluid inlets 150, 152.

[0115] Due to the salinity gradient between the low salinity solution and the high salinity solution, water flows through the membrane 148 from the first chamber 144 to the second chamber 146. Thus, a water flow is created between the first chamber 144 and the second chamber 146, causing the rotor system 180 to rotate.

[0116] The water flows through the membrane 148 into the second chamber 146 and is then discharged through the additional fluid outlet 178. The circulation of water within the second chamber 146 causes the rotation of a second portion 186 of a rotor system 180 contained within the second chamber 14, and therefore also the rotation of the first portion 184 of the rotor system 180. The rotation of the rotor system 180 causes an electrolyte flow within the electrolyte reservoir 130 such that the electrolyte is circulated between the electrolyte supply inlet 134 and the electrolyte return outlet 136.

[0117] As long as the first and second chambers 144, 146 are replenished with the low and high salinity solutions, respectively, water molecules will diffuse through the membrane 148 and this osmotic pressure-generated water flow will activate the rotor system 180, which will cause the formation of electrolyte flow in the electrolyte reservoir 130. The supply system 114 functions in a continuous mode.

[0118] Advantageously, the method may also include a step of evacuating the first and second chambers 144, 146, for example to perform cleaning or maintenance operations. The supply system 14, 114 according to the invention makes it possible to supply an electrolyte flow to the electrolysis unit 12 without the need for energy-consuming pumping devices. The flow generated by osmotic pressure in the permeation unit 40, 140 allows the activation of the movable actuators 42, 142 and the circulation of the electrolyte solution at a rate sufficient to replenish the electrolysis cell 20.

[0119] By limiting the consumption of electrical energy, the supply system 14, 114 according to the invention makes it possible to improve the energy efficiency of the water electrolysis process.

[0120] Furthermore, by using the discarded salt water from the desalination unit 16, the phenomenon of salt concentration at the outlet of the desalination unit 16 can be avoided or at least reduced. [Explanation of symbols]

[0121] 12 Electrolysis unit 14 Supply System 15 Electrolyte makeup flow 30 Electrolyte storage tank 32 Circulation Unit 34 Electrolyte supply inlet 36 Electrolyte recovery outlet 40 Infiltration Units 42 Movable Actuator 44 First Chamber 46 Second Chamber 114 Supply System 130 Electrolyte storage tank 132 Circulation Unit 134 Electrolyte supply inlet 136 Electrolyte recovery outlet 140 Infiltration Unit 142 Movable Actuator 144 First Chamber 146 Second Chamber

Claims

1. A supply system (14, 114) for supplying an electrolyte make-up stream (15) to an electrolysis unit (12), an electrolyte reservoir (30, 130) configured to store an electrolyte solution and including an electrolyte supply inlet (34, 134) and an electrolyte recovery outlet (36, 136), the electrolyte reservoir (30, 130) being configured to be fluidly connected to the electrolysis unit (12) through the electrolyte fluid recovery outlet (36, 136); a circulation unit (32, 132) for circulating the electrolyte solution stored in the electrolyte reservoir (30, 130) to an electrolyte recovery outlet (36, 136); A delivery system comprising: A circulation unit (32, 132), a movable actuator (42, 142) configured to cause a displacement of the electrolyte solution in the electrolyte reservoir (30, 130); and a permeation unit (40, 140) including a first chamber (44, 144) fluidly coupled to a first source of a low salinity solution, a second chamber (46, 146) fluidly coupled to a second source of a high salinity solution, and a semi-permeable membrane (48, 148) separating the first and second chambers (44, 46, 144, 146); Including, the permeation unit (40, 140) is configured to actuate the actuator (42, 142) by permeation between the first and second chambers (44, 46, 144, 146); Supply system.

2. 2. The delivery system (14, 144) of claim 1, wherein the high salinity solution has a salinity mass concentration at least 1.5 times higher than the salinity mass concentration of the low salinity solution, the mass concentration being measured at atmospheric pressure and 25°C.

3. The supply system (14, 144) of claim 1 or 2, wherein the permeation unit (40, 140) is fluidly coupled to a saltwater disposal system (76) of the desalination unit (16).

4. The delivery system (14, 144) of claim 1 or 2, wherein each chamber (44, 46, 144, 146) further comprises a respective outlet (54, 56, 154, 156).

5. A supply system (14, 144) according to claim 1 or 2, wherein the actuator (42, 142) is at least partially housed in the permeation unit (40, 140), in particular in the second chamber (46, 146), such that permeation between the first chamber (44, 144) and the second chamber (46, 146) activates the actuator (42, 142).

6. The supply system (14, 144) of claim 1 or 2, wherein the actuator (42, 142) is at least partially contained within the electrolyte reservoir (30, 130).

7. 3. The delivery system (14) of claim 1 or 2, wherein the movable actuator (42) is a piston (70), and penetration between the first and second chambers (44, 46) displaces the piston (70) along the longitudinal axis (X).

8. 3. The supply system (114) of claim 1 or 2, wherein the movable actuator (142) is a rotor system (180) configured to rotate about an axis of rotation (R), and rotation of the rotor system (180) is caused by permeation between the first and second chambers (142, 144).

9. The delivery system (14, 144) of claim 1 or 2, wherein the semipermeable membrane (48, 148) is made of a composite polymer-based material.

10. In particular for the production of dihydrogen and dioxygen by water electrolysis, electrochemical CO ２ For reduction, electrochemical N ２ In an installation (10) for reduction or chlor-alkali electrolysis, an electrolysis unit (12) adapted to receive an electrolyte make-up flow (15) and including an electrolytic cell (20); - a supply system (14, 144) according to claim 1 or 2, 1. An apparatus (10).

11. 11. The installation (10) of claim 10, wherein the electrolytic cell (20) is a fluid electrolytic cell.

12. The facility (10) of claim 10 or 11, further comprising a desalination unit (16) configured to replenish the permeation unit (40, 140).

13. A method for replenishing an electrolyte make-up stream (15) to an electrolysis unit (12), comprising the steps of: - providing a supply system (14, 144) according to claim 1 or 2; - injecting an electrolyte solution into the electrolyte reservoir (30, 130); injecting a low salinity solution into a first chamber (44, 144) of the osmotic unit (40, 140) and a high salinity solution into a second chamber (46, 146) of the osmotic unit (40, 140), such that a salinity gradient exists between the first and second chambers (44, 46, 144, 146), said salinity gradient creating a flow of water between the first chamber (44, 144) and the second chamber (46, 146), said flow of water actuating the actuator (42, 142); A method comprising:

14. The method of claim 13, wherein injecting the high salinity solution comprises recovering salt water from a salt water disposal system of the desalination unit.

15. The method of claim 13 or 14, further comprising evacuating the first and second chambers (44, 46, 144, 146).

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