Facility and method for producing hydrogen by water electrolysis with gas / liquid separation being carried out in flow conveying lines

Abstract

The invention relates to a facility comprising: - a series of n electrolysers (4) designed to electrolyse water (1) and produce a hydrogen-aqueous solution mixture (5), the series having an overall capacity greater than 40 MW; - a gas-liquid separation device (8) configured to remove the aqueous solution contained in the mixture (5) produced by the series of n electrolysers (4) and produce a hydrogen stream (9). The gas-liquid separation device (8) comprises two flow conveying lines (21, 22) arranged one above the other; either or both of the two conveying lines being supplied with the mixture (5) and the two conveying lines being in fluid communication with one another via one or more segments (23) so that the hydrogen passes from the lower line (22) to the upper line (21) and / or the aqueous solution passes from the upper line to the (21) lower line (22).

Description

[0001] Installation and process for the production of hydrogen by electrolysis of water with gas-liquid separations in the flow delivery lines

[0002] The present invention relates to an installation for producing hydrogen by electrolysis of water and to a method for producing hydrogen using said installation.

[0003] It applies in particular, but not exclusively, to the supply of hydrogen for storage, for example in pressurized form, or to its use in a unit, such as a refinery, for transforming hydrogen into another chemical vector such as methanol, ammonia, or fuels (such as sustainable aviation fuel - in English sustainable aviation fuel SAF) or to its export to a pipeline system, or to its consumption as a combustible gas in a fuel cell or in a burner.

[0004] We know the need to reduce our greenhouse gas production and use renewable energy. Hydrogen is an alternative to hydrocarbons because it is an easily storable energy source, unlike electricity, and its oxidation releases a very high energy (285 kJ / mol). There are several known ways to produce hydrogen; the most advantageous is to electrolyze the water molecule because it is a high-yield reaction that does not produce CO2, unlike the widely used processes of methane and hydrocarbon reforming.

[0005] Electrolysis units are currently composed of a number of modules in which electrolysis takes place as well as a large number of equipment allowing its proper functioning: electrolyzers, separation tanks, pumps, gas coolers, liquid coolers, piping, instrumentation, etc. Large-capacity electrolysis production facilities are therefore designed using a modular approach: a large number of small electrolysis units are placed side by side, in other words in parallel, until the desired quantity of electrolysis is reached. This results in a very large number of equipment which generates:

[0006] - An increase in HSE (Health - Safety - Environment) risks, in particular linked to the risks of explosion due to the presence of hydrogen;

[0007] - An increase in the size of the installation and the floor space occupied by the installation, particularly due to the safety distances to be respected between the different pieces of equipment but also between the equipment and the external environment; and - A significant increase in the price of the installation.

[0008] From this point on, a problem arises: how to provide an improved installation for producing hydrogen by water electrolysis, in other words an installation with limited HSE risk and a reduced number of pieces of equipment.

[0009] A solution of the present invention is a hydrogen production facility comprising:

[0010] - A series of n electrolysers 4 configured to electrolyze water 1 and generate a hydrogen-aqueous solution mixture 5, said series having an overall capacity greater than 40 MW,

[0011] - At least one gas-liquid separation device 8 configured to remove the aqueous solution contained in the hydrogen-aqueous solution mixture 5 generated by the series of n electrolysers 4, and produce a hydrogen flow 9,

[0012] - A means of recovering a hydrogen flow 24,

[0013] - A means for recovering a flow of aqueous solution 25,

[0014] With said gas-liquid separation device 8 comprising two flow conveying lines - an upper conveying line 21 and a lower conveying line 22 - arranged one above the other, with the upper conveying line 21 fluidly connected to the hydrogen flow recovery means 24 and the lower conveying line 22 fluidly connected to the aqueous solution flow recovery means 25; one and / or the other of the two conveying lines being supplied with the hydrogen-aqueous solution mixture 5 and the two conveying lines 21 and 22 being fluidly connected to each other by one or more sections 23 so as to allow a passage of hydrogen from the lower line 22 to the upper line 21 and / or a passage of the aqueous solution from the upper line 21 to the lower line 22.

[0015] In other words, in the solution according to the invention, the hydrogen and the aqueous solution will be separated along the conveyance lines by gravity. The aqueous solution will descend by gravity into the lower conveyance line via the sections while the hydrogen will rise in the upper conveyance line also via the sections. Each section will be able to see both ascending and descending flows. Note that the descending flows may also include condensates that would have formed in the upper conveyance line. It goes without saying that these condensates are essentially made up of water.

[0016] By "at least one gas-liquid separation device" is meant that the installation may comprise several gas-liquid separation devices in parallel or in series. By "conveyor lines arranged one above the other" is meant that they are arranged one above the other along a vertical axis or that they are arranged one above the other but offset horizontally.

[0017] The routing lines can be straight or curved.

[0018] The means for recovering the aqueous solution 25 may comprise a pipe installed in parallel with the lower conveying line 22, preferably below the lower conveying line 22, in which at least part of the flow of aqueous solution may circulate; aqueous solution withdrawn in this case at different points of the lower conveying line 22.

[0019] Preferably, each electrolyzer consists of a stack of several electrolysis cells which may most likely be of the alkaline or PEM (proton exchange membrane) type connected in series, commonly called a stack. The stack is powered by direct current by an electrical distribution system whose output voltage can be adjustable. Other types of electrolysis cells may be used such as AEM (anion exchange membrane) cells, SOEC (solid oxide electrolysis cells), PCEC (proton ceramic electrochemical cell). More generally, any type of electrolyzer may be used.

[0020] By "overall capacity" of the series of n electrolysers, we mean the sum of the n capacities of the n electrolysers.

[0021] Preferably, the series of n water electrolysis modules will have an overall capacity greater than 100MW, or even greater than several hundred MW.

[0022] Typically, for an electrolysis capacity of around 5MW per stack, “n” can be between 8 and 200, preferably between 16 and 40.

[0023] It goes without saying that the series of n water electrolysis modules generates oxygen in addition to hydrogen. Also advantageously, the installation will comprise a second gas-liquid separation device configured to remove the aqueous solution (or water comprising up to approximately 40% by mass of salts) contained in the oxygen-aqueous solution mixture generated by the series of n electrolysers.The installation according to the invention will therefore preferably comprise a means for recovering an oxygen flow and a second gas-liquid separation device comprising two flow conveying lines - an upper conveying line and a lower conveying line - arranged one above the other, with the upper conveying line fluidly connected to the means for recovering the oxygen flow and the lower conduit line fluidly connected to the means for recovering the aqueous solution flow; one and / or the other of the two conveying lines being supplied with the oxygen-aqueous solution mixture 6 and the two lines being fluidically connected to each other by one or more sections so as to allow passage of oxygen from the lower line to the upper line and / or passage of the aqueous solution from the lower line to the upper line.The oxygen flow 15 recovered at the outlet of the second gas-liquid separation device will then be cooled in a cooler 16 to a temperature between 30 and 40°C, then collected in a collection system 19 or will more generally be sent to the atmosphere.

[0024] The water can be stored in a storage tank connected to the water supply circuit upstream of the series of n electrolysers. The water supply circuit can be connected to the running water and includes several water purification units, which can be of different types (e.g. resin and / or activated carbon) for better purification. For example, a conductivity sensor mounted on the water supply circuit allows the degree of purity of the water to be continuously checked. The use of analyzers can also allow the level of salt impurity in the purified water to be monitored.

[0025] The installation according to the invention may comprise loops for recycling the aqueous solution between the gas-liquid separation devices and the series of n electrolysers. Advantageously, each recycling loop will comprise a cooler in order to cool the aqueous solution to a temperature lower than that of the electrolysers, preferably to a temperature between 50 and 80°C, even more preferably to a temperature between 60 and 70°C.

[0026] At the outlet of the installation according to the invention, the hydrogen and oxygen are conducted to extraction circuits. As a safety measure, these extraction circuits may be equipped with gas evacuation means, for example valves or vents, intended to instantly lower the pressure in the event of overpressure or explosion or fire.

[0027] Depending on the case, the installation according to the invention may have one or more of the characteristics below:

[0028] - the gas-liquid separation device 8 is connected to a capacity greater than 40 MW, preferably greater than 100 MW;

[0029] - the two routing lines 21 and 22 are at all points separated from each other by a minimum distance of between 0.1 and 10 m, preferably between 0.5 and 1.5 m;

[0030] - the two routing lines 21 and 22 form an angle a of between 0 and 45°, preferably between 0 and 10°, - the sections 23 are separated from each other by a distance of between 0.5 and 10 m, preferably between 4 and 6 m; Note that if the electrolysers are of the alkaline type, the sections 23 will preferably be separated from each other by a distance of between 4 and 6 m.

[0031] - the two conveying lines 21 and 22 have a diameter expressed in millimeters between 1 and 20 times the overall capacity of the electrolysers 4 expressed in MW, preferably between 3 and 15 times the overall capacity of the electrolysers 4 expressed in MW, and the sections 23 have a diameter expressed in millimeters between 0.1 and 5 times the overall capacity of the electrolysers 4 expressed in MW, preferably between 0.5 and 2 times the overall capacity of the electrolysers (4) expressed in MW. Note that these different diameters make it possible to limit the accumulation of liquids, turbulence, pressure losses and the risks of blockage;

[0032] - the installation comprises a withdrawal pump connected to the means for recovering the aqueous solution 25, and a buffer tank installed between the means for recovering the aqueous solution 25 and the withdrawal pump.

[0033] - the upper conveying line 21 and the buffer tank are fluidically connected by a section T so as to allow a passage of a hydrogen residue from the buffer tank to the upper conveying line 21. Indeed, in the case where there remain a few hydrogen bubbles in the withdrawn aqueous solution, these few bubbles would stick to the upper part of the internal wall of the buffer tank before joining the upper conveying line 21 via the section T. Note that this conveying of the hydrogen residue to the upper conveying line 21 can be done continuously or intermittently by means of an automatically controlled control valve placed on the section T; A separator head can be placed between the buffer tank and the section T in order to facilitate the rise of the hydrogen bubbles.

[0034] - the means for recovering the flow of aqueous solution 25 is associated with a vortex breaker;

[0035] - the installation comprises at least one means for controlling the level of aqueous solution in the lower conveying line 22 and / or in the buffer tank;

[0036] - the installation comprises a single gas-liquid separation device 8 and n lines configured to supply the hydrogen-aqueous solution mixture generated by the n electrolysers 4 to the gas-liquid separation device 8. Note that one or more pipes may recover the flow from the n lines connected to the n electrolysers before sending it to the gas-liquid separation device 8 for the sake of pooling; - the routing lines 21 and 22 have a length expressed in meters of between 0.2 and 2 times the overall capacity of the n electrolysers expressed in MW, preferably of between 0.5 and 1.5 times the overall capacity of the n electrolysers expressed in MW; Note that these lengths apply in particular to the case where the electrolysers are of the alkaline type;

[0037] - the gas-liquid separation device 8 has a hydrogen inventory H of less than or equal to 0.5nh with:

[0038] - n the number of electrolysers 4 and,

[0039] - h the hydrogen inventory in each gas-liquid separation device configured to remove the aqueous solution contained in the hydrogen-aqueous solution mixture, for an installation of capacity similar to the installation according to the invention and comprising n electrolysers associated in series with n balloon-shaped gas-liquid separation devices configured to remove the aqueous solution contained in the hydrogen-aqueous solution mixture; by "inventory" is meant the maximum volume of hydrogen present at each instant t in the gas-liquid separation device; it is generally expressed in m 3 (cubic meter)

[0040] - the gas-liquid separation device 8 is made of a material chosen from carbon steel, stainless steel, duplex steel, nickel, autocatalytic nickel, carbon steel with nickel coating or glass-reinforced plastic with liner (in English GRP: glass reinforced plastic); Note that the gas-liquid separation device may also have a coating of polymer plastic type such as PTFE (Polytetrafluoroethylene) or equivalent; The gas-liquid separation device may also be at least partially heat-insulated.

[0041] - the series of n electrolysers is included in at least one closed or semi-closed building B and the gas-liquid separation device 8 is located outside this building B; the size of the building B is thus reduced;

[0042] - the lines, and preferably the associated valves, are located at least largely outside building B; this also makes it possible to reduce the size of building B and to limit the risks of hydrogen leaks into building B. Furthermore, by placing the valves outside building B, their accessibility is facilitated.

[0043] - the installation comprises pipe supports 26 consisting of a series of transverse beams which extend over the entire length of the gas-liquid separation device and which are connected to longitudinal struts; these pipe supports may be commonly called “piperack”; The height of the piperack will preferably be greater than 3 meters; - the installation comprises a cooler 10 configured to cool the hydrogen 9 leaving the gas-liquid separation device 8;

[0044] - in other words, a single cooler is associated with the single gas-liquid separation device 8; the cooler may be a Peltier effect gas cooler, but more generally a plate exchanger or a tubular exchanger.

[0045] - The installation comprises a purification unit 11 for the hydrogen flow leaving the cooler 10; The impurities to be eliminated are mainly oxygen and water, as well as some traces of salts... The purification unit 11 may be chosen from: a water washing unit for removing salts (for example potassium hydroxide), a cooler coupled or not to the water washing unit and for cooling the flow to a temperature between 30 and 40°C, a catalytic deoxygenation unit, and a drying unit (for example drying by cooling for cooling the flow to a temperature between 5 and 10°C or drying on molecular sieve). Preferably, these different units will be added in series to the installation. Note that the water recovered at the drying outlet may be recycled in the series of n electrolysers.An analysis unit may be placed downstream of this(these) purification unit(s) in order to check the residual concentration of impurities in the hydrogen flow.

[0046] - the installation comprises a unit for compressing the hydrogen flow downstream of the purification unit 11. The type of compressor can be mainly reciprocating, centrifugal or membrane; Note that a compression unit can also be placed upstream of the purification unit 11;

[0047] - the installation comprises a static mixer configured to homogenize the hydrogen-aqueous solution mixture 5 upstream of the gas-liquid separation device 8.

[0048] The present invention also relates to a method for producing hydrogen using an installation according to the invention and comprising: a) A step of electrolysis of water to generate a hydrogen-aqueous solution mixture 5 using a series of n electrolysers 4 having an overall capacity greater than 40 MW, b) A step of conveying the hydrogen and the aqueous solution, generated in step a), to the means for recovering the hydrogen flow and the aqueous solution flow 24 and 25, and c) A gas-liquid separation step making it possible to eliminate the aqueous solution contained in the hydrogen-aqueous solution mixture 5 generated in step a), by means of the gas-liquid separation device 8, so as to provide a hydrogen flow and an aqueous solution flow;

[0049] With the routing step and the separation step being joint. Depending on the case, the method according to the invention may have one or more of the characteristics below:

[0050] - step c) comprises a sub-step of supplying one of the two delivery lines 21 and 22 of the gas-liquid separation device 8 with the hydrogen-aqueous solution mixture.

[0051] - step b) comprises a sub-step of recovering the hydrogen flow at at least one point of the upper conveying line 21 and a sub-step of recovering the aqueous solution flow at at least one point of the lower conveying line 22.

[0052] - step c) is carried out at a temperature between 60 and 100°C.

[0053] - step c) is carried out at a pressure between 1 and 40 bar.

[0054] - The process comprises a step d) of cooling the hydrogen from step c) to a temperature between 30 and 40°C.

[0055] - The process comprises a step e) of purification of the hydrogen cooled in step d).

[0056] - The method comprises a step f) of compressing the hydrogen from step e) to a pressure higher than the pressure of the gas-liquid separation device 8, preferably to a pressure of between 20 and 60 bar. Depending on the uses and in particular mobility applications, a compression step to several hundred bar is necessary.

[0057] Since oxygen is also generated in step a), the method according to the invention will preferably comprise a step of conveying the oxygen and the aqueous solution, generated in step a), to the means for recovering the oxygen flow and the aqueous solution flow and a gas-liquid separation step making it possible to eliminate the aqueous solution contained in the oxygen-aqueous solution mixture 6 generated in step a), by means of the second gas-liquid separation device, so as to provide an oxygen flow and an aqueous solution flow, the oxygen conveying step and the oxygen-aqueous solution separation step being joint.

[0058] As indicated previously, the oxygen 15 recovered at the outlet of the second gas-liquid separation device will then be cooled in the cooler 16 to a temperature between 30 and 40°C, then collected in a collection system 19 or will more generally be sent to the atmosphere.

[0059] Advantageously, the method according to the invention will comprise a step of recycling the aqueous solutions from the gas-liquid separation devices 8 and 14 to the electrolysers 4, preferably after cooling the aqueous solutions to a temperature between 50 and 80°C, even more preferably to a temperature between 60 and 70°C.

[0060] In other words, if we do not take into account the possible coolers which could be used in the purification step 11, the installation does not include 3n coolers as taught in the prior art but only three coolers:

[0061] - a cooler 10 configured to cool the hydrogen 9 leaving the gas-liquid separation device 8;

[0062] - a cooler 16 configured to cool the oxygen 15 leaving the gas-liquid separation device 14; and

[0063] - a cooler configured to cool the aqueous solutions from the gas-liquid separation devices 8 and 14.

[0064] The installation will now be described in more detail with the aid of Figures 1 to 4. Figure 1 illustrates the general operation of the installation according to the invention.

[0065] Water 1 from a supply or storage tank 2 is introduced into a water treatment unit 3 (water treatment preferably means demineralization and deionization). The purified water is then injected into the aqueous solution circuit to be subsequently electrolyzed in a series of n electrolyzers 4 (stacks), said series having an overall capacity greater than 40 MW. Leaving the series of n electrolyzers 4, a hydrogen-aqueous solution mixture 5 and an oxygen-aqueous solution mixture 6 are recovered. The hydrogen-aqueous solution mixture 5 feeds the first gas-liquid separation device 8 configured to remove the aqueous solution contained in the hydrogen-aqueous solution mixture 5 generated by the series of n electrolyzers 4. The hydrogen stream 9 leaving the gas-liquid separation device 8 is saturated with water.The hydrogen stream 9 is generally cooled to a temperature between 40 and 30°C in a cooler 10 before being introduced into a purification unit 11. The hydrogen stream 12 leaving the purification unit 11 has a purity greater than 99.99%, preferably greater than 99.999%. The hydrogen stream 12 may optionally be compressed to a pressure greater than that of entry into the purification unit 11, preferably greater than 15 bar before being stored 18 or conveyed into an extraction circuit.

[0066] The oxygen-aqueous solution mixture 6 feeds the second gas-liquid separation device 14 configured to remove the aqueous solution contained in the oxygen-aqueous solution mixture 6 generated by the series of n electrolysers 4. The oxygen flow 15 leaving the second gas-liquid separation device 14 is saturated with water. The oxygen flow 15 is cooled to a temperature between 40 and 30°C in a cooler 16. The oxygen flow 17 leaving the cooler 16 has a purity greater than 98%, preferably greater than 99%; it will be stored in a collection system 19 or routed to an extraction circuit.

[0067] Figure 1 does not illustrate the characteristics of the gas-liquid separation devices implemented in the installation according to the invention. Indeed, said devices are described in more detail using Figures 2 to 4.

[0068] Figure 2 specifically illustrates the first variant of the installation according to the invention. In this first variant, the installation comprises two gas-liquid separation devices 8 configured to remove the aqueous solution contained in the hydrogen-aqueous solution mixture 5 generated by the series of n electrolyzers 4; n being equal to 12 in the example of Figure 2. Each pair of electrolyzers 4 of the series of n electrolyzers (note that it could be a question not of pairs of electrolyzers but typically of groups of electrolyzers comprising between 2 and 4 electrolyzers) provides two flows of hydrogen-aqueous solution mixtures 5 which are combined in a single pipe 27 which is fluidically connected to one of the two delivery lines of one of the two gas-liquid separation devices 8. Advantageously, the gas-liquid separation devices 8 are supported by a piperack 26.The hydrogen flow is recovered at one or more withdrawal points located on the two upper conveying lines of the two gas-liquid separation devices 8 and the aqueous solution flow is recovered at one or more withdrawal points on the two lower conveying lines of the two gas-liquid separation devices 8. Note that even if Figure 2 does not represent the part of the installation relating to oxygen for the sake of simplicity, similar equipment is present for the oxygen part: thus there will be in particular two gas-liquid separation devices 14 configured to eliminate the aqueous solution contained in the oxygen-aqueous solution mixture 6 generated by the series of n electrolysers 4.

[0069] Figure 3 specifically illustrates the second variant of the installation according to the invention. In this second variant, the installation comprises a gas-liquid separation device 8 configured to remove the aqueous solution contained in the hydrogen-aqueous solution mixture 5, per pair of electrolyzers of the series of n electrolyzers (note that it could not be a question of a pair of electrolyzers but typically of groups of electrolyzers comprising between 2 and 4 electrolyzers). n being equal to 12 in the example of Figure 3, in this example there will be 6 gas-liquid separation devices 8. Each pair of electrolyzers 4 of the series of n electrolyzers provides two flows of hydrogen-aqueous solution mixtures 5 which feed one of the two conveying lines of one of the two gas-liquid separation devices 8. Note that in this second variant each gas-liquid separation device will be supported by its own piperack.A hydrogen stream is recovered at one or more draw-off points located on each upper conveying line of the gas-liquid separation devices 8 and sent to a recovery means 24 which in this second variant will be a first collection pipe. Similarly, a stream of aqueous solution is recovered at one or more draw-off points located on each lower conveying line of the gas-liquid separation devices 8 and sent to a recovery means 25 which in this second variant will be a second collection pipe. Note that even if Figure 3 does not represent the part of the installation relating to oxygen for the sake of simplicity, similar equipment is present for the oxygen part: thus, there will be in particular a gas-liquid separation device 14 configured to eliminate the aqueous solution contained in the oxygen-aqueous solution mixture 6 per pair of electrolyzers of the series of n electrolyzers).n being equal to 12 in the example of figure 3, in this example there will be 6 gas-liquid separation devices 14. A flow of oxygen is recovered at one or more withdrawal points located on each upper conveying line of the gas-liquid separation devices 14 and sent into a recovery means which in this second variant will be a third collection pipe. The flow of aqueous solution recovered, for its part, at one or more withdrawal points located on each lower conveying line of the gas-liquid separation devices 14 is sent into the second collection pipe or into a fourth collection pipe.

[0070] Figure 4 illustrates different types of gas-liquid separation devices that can be implemented within the scope of the invention. In case A, the lower conveying line 22 is parallel to the floor of the installation and the upper conveying line 21 is positioned so as to form an angle α with the lower conveying line 22. In case B, the lower conveying line 22 forms an angle β with a horizontal axis parallel to the floor and the upper conveying line 21 is positioned so as to form an angle α with the lower conveying line 22. Note that β can be between 0 and 20°, preferably between 0 and 5°. In case C, the two conveying lines 21 and 22 are parallel to the floor of the installation. In all three cases, the arrows show the direction of the flows.We can clearly see that the sections see two flows: an upward flow of hydrogen (or oxygen if it is a gas-liquid separation device configured to separate oxygen from the aqueous solution) and a downward flow of aqueous solution.

[0071] Finally, the present invention also relates to a method for manufacturing the hydrogen production installation according to the invention, characterized in that it comprises a step of installing the electrolysers in at least one building B and a step of manufacturing, on site or by modular assembly, the gas-liquid separation device 8 outside the building B. By "on-site manufacturing" is meant that the gas-liquid separation device can be manufactured by assembling all the equipment on site as opposed to a "modular assembly" which corresponds to the installation of one or more skids, manufactured outside the site. In the case of assembly, the assembly of modules comprising between 10 and 14 m of length of conveying lines will be preferred. Note that "off-site manufacturing" is meant manufacturing on site outside the building(s) B.

[0072] The solution according to the invention, by combining the routing of the hydrogen flow and its separation with the aqueous solution, makes it possible to limit the places where the gas remains static and thus limits HSE risks.

[0073] Furthermore, the size of the installation and the cost of the installation are also minimized by the reduction in the number of equipment: no gas-liquid separation tank (apart from the buffer tank which can possibly be considered as a separator tank, but this will include at most a few hydrogen bubbles and will thus be almost entirely filled with aqueous solution), a combination of the routing of the flows with the gas-liquid separations, at most one gas-liquid separation device 8 configured to remove the aqueous solution contained in the hydrogen-aqueous solution mixture 5 for two electrolysers, at most one gas-liquid separation device 14 configured to remove the aqueous solution contained in the oxygen-aqueous solution mixture 6 for two electrolysers, only three coolers (the cooler 10 configured to cool the hydrogen 9 leaving the gas-liquid separation device 8,the cooler 16 configured to cool the oxygen 15 leaving the gas-liquid separation device 14 and the cooler of the aqueous solution recycling loop), a number of pumps which has been divided by 5 compared to the installations of the prior art. By "installations of the prior art" is meant installations which comprise n electrolyzers, n gas-liquid separation devices configured to remove the aqueous solution contained in the hydrogen-aqueous solution mixture, n gas-liquid separation devices configured to remove the aqueous solution contained in the oxygen-aqueous solution mixture, 3n coolers, as well as the associated number of pumps (typically around fifteen) and pipes. Also, if we count the total number of equipment we note that it has been divided at least by three in the installation according to the invention. From there,compared to an installation according to the prior art, the installation according to the invention has a building B whose height has been reduced by at least 25%, and whose footprint has been divided between 2 and 5 times. This notably results in easier air renewal in the building. Concerning the overall footprint (footprint of the building and other equipment including the gas-liquid separation devices), this has also been reduced by 10 to 30%.,

[0074] In other words, the solution according to the invention makes it possible to:

[0075] - reduce the number of equipment; - limit HSE (Health - Safety - Environment) risks by reducing the number of devices that accumulate hydrogen;

[0076] - reduce the size of the installation and the floor space occupied. Indeed, by reducing the number of equipment, the safety distances are also reduced; and

[0077] - reduce the cost of installation.

Claims

CLAIMS 1. Hydrogen production facility comprising: - A series of n electrolysers (4) configured to electrolyze water (1) and generate a hydrogen-aqueous solution mixture (5), said series having an overall capacity greater than 40 MW, - At least one gas-liquid separation device (8) configured to remove the aqueous solution contained in the hydrogen-aqueous solution mixture (5) generated by the series of n electrolysers (4), and produce a hydrogen flow (9), - A means of recovering a hydrogen flow (24), - A means for recovering a flow of aqueous solution (25), With said gas-liquid separation device (8) comprising two flow conveying lines - an upper conveying line (21) and a lower conveying line (22) - arranged one above the other, with the upper conveying line (21) fluidically connected to the hydrogen flow recovery means (24) and the lower conveying line (22) fluidically connected to the aqueous solution flow recovery means (25); one and / or the other of the two delivery lines being supplied by the hydrogen-aqueous solution mixture (5) and the two delivery lines (21) and (22) being fluidically connected to each other by one or more sections (23) so as to allow a passage of hydrogen from the lower line (22) to the upper line (21) and / or a passage of the aqueous solution from the upper line (21) to the lower line (22).

2. Hydrogen production installation according to claim 1, characterized in that the two delivery lines (21) and (22) are at all points separated from each other by a minimum distance of between 0.1 and 10 m, preferably between 0.5 and 1.5 mA.

3. Hydrogen production installation according to claim 2, characterized in that the two conveying lines (21) and (22) form an angle (a) between 0 and 45°, preferably between 0 and 10°.

4. Hydrogen production installation according to one of claims 1 to 3, characterized in that the sections (23) are separated from each other by a distance of between 1 and 5 m, preferably between 2 and 3 m.

5. Hydrogen production installation according to one of claims 1 to 4, characterized in that the two conveying lines (21) and (22) have a diameter expressed in millimeters between 1 and 20 times the overall capacity of the electrolysers (4) expressed in MW, preferably between 3 and 15 times the overall capacity of the electrolysers (4) expressed in MW, and the sections (23) have a diameter expressed in millimeters between 0.1 and 5 times the overall capacity of the electrolysers (4) expressed in MW, preferably between 0.5 and 2 times the overall capacity of the electrolysers (4) expressed in MW.

6. Hydrogen production installation according to one of claims 1 to 5, characterized in that it comprises a withdrawal pump connected to the means for recovering the aqueous solution (25), and a buffer tank installed between the means for recovering the aqueous solution (25) and the withdrawal pump.

7. Hydrogen production installation according to claim 6, characterized in that the upper conveying line (21) and the buffer tank are fluidically connected by a section T so as to allow a passage of a hydrogen residue from the buffer tank to the upper conveying line (21).

8. Hydrogen production installation according to claim 7, characterized in that the routing lines (21) and (22) have a length expressed in meters of between 0.2 and 2 times the overall capacity of the electrolysers (4) expressed in MW, preferably of between 0.5 and 1.5 times the overall capacity of the electrolysers (4) expressed in MW.

9. Installation according to one of claims 1 to 8, characterized in that the gas-liquid separation device (8) has a hydrogen H inventory less than or equal to 0.5nh with: - n the number of electrolysers (4) and, - h the hydrogen inventory in each gas-liquid separation device configured to eliminate the aqueous solution contained in the hydrogen-aqueous solution mixture, for an installation of capacity similar to the installation according to the invention and comprising n electrolysers associated in series with n balloon-shaped gas-liquid separation devices configured to eliminate the aqueous solution contained in the hydrogen-aqueous solution mixture.

10. Installation according to one of claims 1 to 9, characterized in that the gas-liquid separation device (8) is made of a material chosen from carbon steel, stainless steel, duplex steel, nickel, autocatalytic nickel, carbon steel with nickel coating or glass-reinforced plastic with liner (GRP).

11. Installation according to one of claims 1 to 10, characterized in that the series of n electrolysers (4) is included in at least one closed building B and the gas-liquid separation device (8) is located outside this building B.

12. Installation according to one of claims 1 to 11, characterized in that it comprises a cooler (10) configured to cool the hydrogen (9) leaving the gas-liquid separation device (8).

13. A method for producing hydrogen using a facility as defined in one of claims 1 to 12 and comprising: a) A step of electrolyzing water to generate a hydrogen-aqueous solution mixture (5) using a series of n electrolyzers (4) having a total capacity greater than 40 MW, b) A step of conveying the hydrogen and the aqueous solution, generated in step a), to the means for recovering the hydrogen flow and the aqueous solution flow (24) and (25), and c) A gas-liquid separation step for removing the aqueous solution contained in the hydrogen-aqueous solution mixture (5) generated in step a), by means of the gas-liquid separation device (8), so as to provide a hydrogen flow and an aqueous solution flow; With the routing step and the separation step being joint.

14. Method for producing hydrogen according to claim 13, characterized in that step c) comprises a sub-step of supplying at least one of the two delivery lines (21) and (22) of the gas-liquid separation device (8) with the hydrogen-aqueous solution mixture.

15. Method for producing hydrogen according to one of claims 13 or 14, characterized in that step b) comprises a sub-step of recovering the hydrogen flow at at least one point of the upper conveying line (21) and a sub- step of recovering the flow of aqueous solution at at least one point of the lower conveying line (22).

16. Method for manufacturing the hydrogen production installation as defined in one of claims 1 to 12, characterized in that it comprises a step of installing the electrolysers in at least one building B and a step of manufacturing, preferably on site, the gas-liquid separation device (8) outside the building B.

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