Feed water preparation method and feed water preparation system for alkaline electrolysis system

Abstract

A feed water preparation system in a water electrolyser, suitable for producing hydrogen and oxygen using alkaline water in one or more pressurized electrolyser stacks (2), and comprising a product gas conditioning system having a safety valve blow-off stream conduit (11) connected to a feed water container (9), and / or a reduced pressure flow conduit (31) connected to a gas cleaning container on the water supply container (9).

Description

Technical Field

[0001] This invention relates to a method for preparing feedwater for an alkaline water electrolysis system and a feedwater preparation system for a water electrolysis cell suitable for producing hydrogen and oxygen using alkaline water in one or more pressurized electrolysis cell stacks, and including a product gas conditioning system. Background Technology

[0002] In water electrolyzers that produce hydrogen and oxygen by splitting water, especially in pressurized electrolyzers using a rich alkaline aqueous solution as the electrolyte, it is desirable that the alkaline portion of the electrolyte remain within the electrolyzer system and not escape the unit along with the product gases hydrogen and oxygen. In today's systems of this type, design pressures up to 50 bar are common, with system pressures typically around 35-40 bar. Systems designed to reach 90-120 bar have also been developed. The high pressure in such systems allows the generated gases to exit the electrolyzer unit at system pressure, and users of the gas or a combination of gases are happy to receive hydrogen or oxygen at high pressure. Safety measures such as safety valves are necessary to ensure that pressure can be released in case of valve failure or other reasons exceeding the system or design pressure, and the blow-out stream from such valves is typically released directly into the atmosphere. Attempts to capture the alkaline components and / or fluids in such blow-out streams have failed. Furthermore, when such systems are set to a safe state, nitrogen or similar inert gases are typically introduced into pipes and containers to ensure that trace amounts of oxygen and hydrogen remain in the plant. This so-called scavenging process may also flush out alkaline particles that could crystallize along a certain length of pipe, and since all scavenging gases are typically released directly into the atmosphere, this alkaline component is usually lost. Furthermore, such systems may include high-pressure gas containers that need to be depressurized to bring the system to a safe state; if this depressurized gas is released into the atmosphere, trace amounts of alkaline components may escape with this airflow. Summary of the Invention

[0003] In the alkaline electrolyzer system of the above type, a method for preparing feedwater is provided, wherein each of one or more electrolyzer stacks has at least one diaphragm separating an oxygen-producing half-cell from a hydrogen-producing half-cell, and wherein each oxygen-producing half-cell delivers an oxygen-electrolyte mixture, each hydrogen-producing half-cell delivers a hydrogen-electrolyte mixture, and thereby each mixture is separated in its respective separator into a product stream mainly composed of oxygen and an oxygen-deficient electrolyte stream, and a product stream mainly composed of hydrogen and a hydrogen-deficient electrolyte stream, wherein the electrolyte stream is replenished by water from a feedwater container.

[0004] According to the present invention, whenever a safety valve is activated, the feedwater container receives a blown material flow from at least one safety valve, and / or, whenever the system depressurization is initiated, the feedwater container receives a blown material flow generated by the depressurization of a pressurized container containing product gas.

[0005] If the safety valve in question is a separator container safety valve, the outflow from the safety valve may contain a high proportion of alkaline water mixed with the corresponding product gas. Once inside the feed tank, it is relatively easy to provide a method for at least partial separation between the fluid and gaseous portions of this flow, retaining the liquid portion within the feed tank, thereby also retaining the alkaline component of the flow.

[0006] Similar opportunities arise from naturally occurring material flows when it is necessary to depressurize the processing vessel, which is part of the gas conditioning line downstream of the separator. This requirement arises whenever the system needs to be shut down and brought to a safe state. Again, to prevent the release of alkaline elements into the external environment, the material flow originating from the depressurization site is also piped to the feedwater tank. Thus, liquids containing potentially trace amounts of alkaline components are easily confined within the feedwater vessel, as are any solid particles that may be present in the material flow.

[0007] In one embodiment, the blown material flow is tangentially introduced onto the inner cylindrical surface within the feed container, resulting in the formation of a vortex. As a result, any solids and liquids may settle onto the inner cylindrical surface, and gas exits the container through an outlet pipe arranged coaxially with the central axis of the inner cylindrical surface.

[0008] The task of separating liquid and / or solid elements from a gas can be carried out in a variety of ways; however, in the present case, the formation of vortices is relatively easy to achieve when the blown material stream and / or depressurized stream arrive at the feed tank at a fairly fast speed, and it takes up less space compared to other types of separation methods.

[0009] In one embodiment of the water preparation method, the water supply container receives alkaline emissions from the filtration and drying process of the corresponding product gas stream.

[0010] This supply also helps ensure that any alkaline substances remain within the system. Multiple drain pipes are typically embedded in the system's gas conditioning unit, each supplying a liquid stream that includes at least a trace amount of alkaline components from the electrolyte. This liquid stream preferably flows back to the feedwater container via a pipe to ensure that the alkaline component is not lost from the system. The return of the drain pipes to the feedwater tank also helps maintain low water consumption and brings it closer to the ideal minimum corresponding to the hydrogen and oxygen produced.

[0011] In one embodiment of the water preparation method, the water from the water supply container and any possible alkaline material dissolved in the water are pressurized and used in the product gas cleaning process in the gas cleaning container, wherein any possible alkaline substances carried in the product gas stream are dissolved in the pressurized water, and further, the resulting alkaline-rich water enters a corresponding separator to replenish the water lost in the half-cell during electrolysis.

[0012] In the cleaning container, the product gas is thoroughly mixed with the fluid within, thereby trapping particles and / or droplets of electrolytes and alkaline components within the fluid. One method of achieving this mixing is by permeating small gas bubbles upwards through a liquid column. In this case, liquid water originates from the feed tank, and the water in the cleaning container becomes further enriched with alkaline components, thus retaining the alkaline components within the system.

[0013] In one embodiment of the water preparation method, a first water supply container receives fluid and gas from a hydrogen preparation system and delivers the water to a hydrogen cleaning process, while a second water supply container receives fluid and gas from an oxygen preparation system and delivers the water to an oxygen cleaning process.

[0014] In some electrolyzer systems, the lean alkaline liquid stream from the gas separator is mixed before being reinjected into one or more electrolyzer stacks. In such systems, water from a cleaning container can be pumped into this mixed stream from both separators. However, in the current case, there are two separate electrolyte streams: a hydrogen-producing stream and an oxygen-producing stream, and an equivalent gas conditioning process is arranged for each product stream. Therefore, a gas cleaning container is provided for each conditioning process, which then delivers the alkaline-rich water stream to the corresponding separator. In this way, cross-contamination between the gases in the electrolyte fluid is minimized.

[0015] In one aspect, the object of the present invention is achieved by a feedwater preparation system in an alkaline water electrolysis system suitable for producing hydrogen and oxygen using alkaline water in one or more pressurized electrolyzer stacks, wherein each stack has at least one diaphragm separating an oxygen-producing half-cell from a hydrogen-producing half-cell, thereby each oxygen-producing half-cell is suitable for conveying an oxygen-electrolyte mixture and each hydrogen-producing half-cell is suitable for conveying a hydrogen-electrolyte mixture, thereby conveying each mixture through pipes to a corresponding separator, and separating in the separator into a product gas stream mainly composed of oxygen and an oxygen-lean electrolyte stream, and a product gas stream mainly composed of hydrogen and a hydrogen-lean electrolyte stream, thereby supplementing the electrolyte stream with water from a feedwater container, and wherein the alkaline water electrolysis system further includes a product gas preparation system.

[0016] According to this aspect of the invention, the safety valve blow-out material flow pipe is connected to the water supply container, and / or the depressurization flow pipe from the gas cleaning container is also connected to the water supply tank.

[0017] Both the discharge from the safety valve and the pressure-reducing flow may contain materials with trace amounts of electrolyte-based alkaline components. Therefore, connecting these two alkaline material sources to the feedwater container ensures minimal loss of alkaline materials from the system. The alkaline components are typically potassium or sodium. In this example, potassium is used.

[0018] In one embodiment of the water preparation system, a safety valve conduit and a material flow tangentially connect to a cylindrical portion in the water supply container to discharge the material flow along an inner cylindrical surface portion within the water supply container. Furthermore, an outlet conduit is coaxially arranged with the cylindrical axis of the inner cylindrical surface portion in the water supply container and directly connected to the atmosphere.

[0019] This arrangement should ensure that the gas and fluid added to the feed tank exhibit a cyclone-like flow pattern. This cyclone-like flow pattern helps ensure that any solids or liquids in the material flow entering the feed container settle onto the cylindrical portion within the feed container and flow downwards through the cyclone opening into the liquid already present in the feed tank, thus remaining in the container and not being swept away by the airflow exiting the container via a coaxially arranged pipe. The pressure difference between the arriving outflow material and the low pressure within the feed container also ensures the cyclone effect. This low pressure in the feed container is also maintained by an outlet pipe open to the atmosphere, the flow area of ​​which is at least several times that of the safety valve pipe. The low pressure maintained within the feed tank also ensures that, under no circumstances will the alkaline water in the tank flow back into the pure water pipes or the pure water treatment system connected to the feed tank.

[0020] In one embodiment of the water preparation system, the water container is connected to the drain pipe of another gas regulator in the gas preparation system.

[0021] By installing this additional connection, it can be ensured that only a small amount of alkaline components leave the system.

[0022] In one embodiment of the water preparation system, a water outlet pipe from the lower part of the water supply container is connected to a water supply pressure pump and is adapted to provide the water supply material flow to the gas cleaning container. In addition, the pipe connects the gas cleaning container and the gas separator to each other, so that water from the water supply container can enter the gas separator in the form of an alkaline water flow through the gas cleaning device, thereby replenishing the water lost during water electrolysis and ensuring that any alkaline substances that may escape from the gas separator container with the gas flow are returned to the electrolyte of the system.

[0023] With the feedwater container open to the atmosphere and thus maintained at ambient pressure, a pressure pump is inserted into the piping between the feedwater container and the gas cleaning container, which is maintained at system pressure. The pressure pump then increases the pressure in the feedwater stream supplied to the gas cleaning container. The fluid flow from the gas cleaning container into the separator ensures that any alkaline components washed away from the product gas are returned to the electrolyte stream entering and exiting the stack.

[0024] In one embodiment of the water preparation system, a first water supply container is connected to a drain pipe and filter in the hydrogen preparation system, and is also connected to a hydrogen cleaning container for supplying water to the hydrogen cleaning container. A second water supply container is connected to a drain pipe and filter in the oxygen preparation system, and is also connected to an oxygen cleaning container for supplying water to the oxygen cleaning container.

[0025] Using feedwater containers in hydrogen and oxygen cleaning systems ensures that no alkaline components are flushed out of the system. In many cases, the generated oxygen is not used for any industrial purpose but is released into the atmosphere. However, it may still be necessary to clean this product gas; therefore, it is advantageous to recover any alkaline components that escape during the separation process along with the generated oxygen.

[0026] Various exemplary and non-limiting embodiments of the construction and operation methods, as well as their additional purposes and advantages, will be best understood from the following description of specific exemplary and non-limiting embodiments when read in conjunction with the accompanying drawings.

[0027] It should be emphasized that the term "comprising / including / consisting of" as used in this specification is used to specify the presence of the feature, integer, step or component, but does not exclude the presence or addition of one or more other features, integers, steps, components or groups thereof. Attached Figure Description

[0028] The invention will be described in more detail below with reference to the embodiments shown in the accompanying drawings. It should be emphasized that the embodiments shown are for illustrative purposes only and should not be used to limit the scope of the invention.

[0029] Figure 1 A flowchart showing the water supply container and its main components, as well as the material flow associated with the container. Figure 2 A top horizontal sectional view of the water supply container is shown. Figure 3 A 3D vertical cross-sectional view of the water tank is shown. Figure 4 The main outline of the cross-sectional view of the tangential inflow path is shown. Figure 5 This is a schematic diagram of an alkaline water electrolysis system. Figure 6This is an idealized diagram of a built-in cyclone component in a water supply tank. Figure 7 A schematic diagram of an electrolyzer with only a single cell 22 is shown, and Figure 8 As shown Figure 5 The electrolyzer system shown is only the hydrogen regulation section of the system. Detailed Implementation

[0030] exist Figure 5 The diagram schematically illustrates some of the main components of the alkaline water electrolysis system 1. Four electrolytic cell stacks 2 are shown, labeled "cell stack 1", "cell stack 2", "cell stack 3", and "cell stack 4", respectively. Each cell stack 2 includes multiple individual cells 22. Figure 7 The diagram schematically illustrates such a battery. Each single cell 22 includes an oxygen-producing half-cell 4 and a hydrogen-producing half-cell 5, and a separator 3 that separates the two half-cells 4 and 5 and ensures that the gases (i.e., oxygen and hydrogen) produced by the cell 22 do not mix. Preferably, the electrolyzer stack 2 should include a predetermined number of cells 22, and as is known in the art, the electrolyte and product streams flowing into and out of the cells 22 in each electrolyzer stack 2 should be delivered to each half-cell 4 and 5 through internal manifolds (not shown) of the four stacks.

[0031] like Figure 5 As shown, the external feed manifolds should deliver oxygen product gas and electrolyte mixture 27 and hydrogen product gas and electrolyte mixture 28 from each stack 2 to the corresponding separator containers 23, 24. Similar feed manifolds should ensure that depleted electrolytes 25, 26 are returned to stack 2. (See diagram for details.) Figure 5 As shown, the external manifold structure is located between the stacks. This manifold structure allows four stacks 2 to be driven using only two shared separator containers 23, 24. Any number of stacks can be used with two separators, but the increased pipe length is generally a limitation, such as... Figure 8 In the illustrated embodiment, six stacks 2 and one separator 24 are disclosed. A second separator 23 must also be part of this system, but... Figure 8 Not shown in the image.

[0032] The electrolyte supplied to stack 2 is replenished with alkaline-rich water 13, which is piped from the corresponding gas cleaning container to separators 23 and 24. Figure 5 and Figure 8The diagram shows a gas cleaning container 21 that receives and discharges the same hydrogen product stream 7 from the hydrogen separator container 24, but now contains almost no trace amounts of alkaline components in the electrolyte. The alkaline components in the hydrogen (and oxygen) product streams 7 and 6 directly from the separators 23 and 24 are too high for most uses of the hydrogen and oxygen product gases, but by capturing this alkaline component in the aqueous phase in the gas cleaning container 21, the product gases will be free of this alkaline component. Thus, by further feeding alkaline-rich water 13 from the cleaning container 21 into the separator 24 to replenish the water lost during electrolysis, the alkaline components in the electrolyte stream will remain within the alkaline water electrolysis system 1.

[0033] exist Figure 8 , Figure 5 and Figure 1 The invention discloses a water supply container 9, which serves as a receiver for the outflow 11 from the safety valve 12 of the hydrogen treatment system and also as a receiver for one or more fluid discharge effluents 8 originating from the hydrogen treatment system. The water supply container 9 also supplies water 20 to a hydrogen cleaning container 21, and as described above, another alkaline water flow 13 is piped from the gas cleaning container 21 to a hydrogen separator 24.

[0034] Similarly, the oxygen separator container 23 should be installed in such a way that it delivers oxygen to an oxygen cleaning container (not shown, but corresponding to the hydrogen cleaning container 21 and connected to the oxygen separator container 23), and further connected via the oxygen cleaning container to an oxygen feedwater container (not shown, but corresponding to the hydrogen feedwater container 9 and delivering water to the oxygen cleaning container), which will be a receiver of gas and / or water flows originating from the oxygen treatment system, including outflows from one or more safety valves in the oxygen treatment system (such as a safety valve (not shown) on the oxygen separator 23).

[0035] During any system shutdown, depressurization is required for safety reasons, and containers such as gas cleaning container 21 also need to be depressurized. This will produce a material stream 31 containing trace amounts of water from cleaning container 21, thus containing some trace alkaline components from the electrolyte used. Therefore, as Figure 8 and Figure 5 As shown, this flow 31 is also added to the flow line or pipe 11 originating from the safety valve 12 of the separator in question.

[0036] Both hydrogen and oxygen product gases undergo multiple processing steps. The first step is the separation process in separators 23 and 24. The next step is gas cleaning in the corresponding gas cleaning containers. After this, as... Figure 8As shown in container 32 on the hydrogen side, other gas regulators, such as filters, dryers, and coolers, can be used to ensure the gas delivery 33 from the system is maintained, depending on given customer quality requirements or environmental requirements (in the case of the atmosphere as the receiver for gases such as oxygen). Some of these processes, such as drying, produce byproducts, such as water containing trace amounts of alkaline components. All these byproducts can now be safely piped back to the corresponding feedwater container, thus ensuring that the alkaline components are not lost through the gas flow 33 delivered to the customer.

[0037] A pure water supply line 10 is arranged to deliver pure water to a feedwater container 9 to compensate for water consumption in the electrolysis system. The water is treated to remove non-aqueous substances such as calcium and other contaminants that could accumulate in the system. The feedwater container 9 is directly connected to the atmosphere via a coaxially arranged outlet pipe 16, so the pure water supply line 10 can operate at pressures only slightly above atmospheric pressure, for example, 1 bar above atmospheric pressure, and is still protected against potential backflow of alkaline water from the feedwater container 9.

[0038] However, any outflow of material 11, 31 from safety valves or pressure relief processes may reach or even exceed the system pressure in pressurized reactors, separator vessels, and gas handling systems, and therefore, the feedwater container 9 should be ideally sized to withstand such high pressure.

[0039] exist Figure 2 and Figure 3 The top of the water supply container 9 is shown in the figure, which has an inner cylindrical surface 14. A short pipe indicates the inlet point for the material flows 11, 31 introduced into the container 9, and the short pipe has an inclined outlet designed to give the material flow an inflow direction tangential to the cylindrical surface portion 14. Therefore, a vortex or cyclone material flow is intended to be generated along the cylindrical surface portion 14. Figure 4 The diagram illustrates a finer tangential flow inlet for the material flow 11 as it enters the cylindrical portion of the feedwater container. This design allows more particles and fluid to settle onto the inner cylindrical surface of the container 9. In both cases, the desired swirling effect is enhanced by the outlet pipe 16, whose central axis 17 is coaxial with the cylindrical axes of the cylindrical portions 14 and 15 within the container 9. Preferably, the outlet pipe extends downwards into the container 9 and has a lowermost edge extending to a point slightly below the inlet point of the material flow 11 but above the water level in the feedwater container 9.

[0040] exist Figure 6In the figure, the cylindrical surface 15 is schematically shown as an insertion element in the container 9. The insertion element has a downward-pointing conical portion 30, the end of which is a cyclone outlet 29 for entering the water supply container 9. The material flow 11, introduced tangentially onto the cylindrical surface 15 through the conical portion or cyclone surface 30, should rotate toward the outlet 29 at an increasingly faster speed. This enhances the precipitation of the portion of material in the material flows 11, 31 that is denser than the gas phase. The outlet conduit 16 is arranged coaxially with the cylindrical surface 15; in this embodiment, the outlet conduit does not need to be aligned with the longitudinal axis of the water supply container 9. Preferably, the lowermost extension of the conduit 16 is slightly above the outlet 29 of the conical cyclone-enhancing surface 30. An advantage of this embodiment is that any obstruction to the cyclone-like rotation of the material flows 11, 31 on the inner surface of the water supply container 9, such as inspection openings or other inlets into the container, will not interfere with the swirling flow along the inner cyclone surface 30 and / or the cylindrical portion 15 within the water supply container 9.

[0041] Figure 8 Safety valve 12 is schematically disclosed. Additionally, a main pump 34 is shown, which can drive alkaline electrolyte stream 26 and hydrogen product gas and electrolyte stream 28 to or from a series of stacks 2. A heat exchanger 35 is inserted into the electrolyte stream between separators 24, 23 and stacks 2 to ensure that the stacks receive electrolyte at a constant temperature.

[0042] Water supply pressure pump 19 Figure 8 and Figure 5 As shown, the pump is designed to increase the pressure of feed water flowing from the feed container to the system pressure so that the water can now enter the cleaning container 21 under system pressure.

[0043] Currently, alkaline water electrolyzers are driven at pressures of 30 to 40 bar. However, it is anticipated that systems operating at pressures up to 120 bar will be used in the future.

[0044] It should be noted that the accompanying drawings and the above description illustrate exemplary embodiments in a simple and illustrative manner. Many specific mechanical details have not been shown, as those skilled in the art should be familiar with such details, and these details only unnecessarily complicate this description.

[0045] Explanation of reference numerals in the attached figures 1. Alkaline water electrolysis system 2. Electrolytic cell stack 3. Diaphragm 4. Half-cell / Oxygen-producing half-cell 5. Half-cell / Hydrogen-producing half-cell 6. Oxygen product airflow 7. Hydrogen product gas flow 8. Fluid discharge effluent 9. Water supply container 10. Pure water supply 11. Blowing out material flow 12. Safety valve 13. Alkaline feedwater flow 14. The cylindrical part in the water supply tank 15. Inner cylindrical surface 16. Coaxially arranged outlet pipes 17. The central axis of the cylindrical part in the water supply tank. 18. Excessive airflow 19. Water supply pressure pump 20. Water supply material flow and outlet pipelines 21. Gas cleaning container 22. Single cell (cell stack) 23. Oxygen separator 24. Hydrogen separator 25. Oxygen-deficient electrolyte flow 26. Hydrogen-poor electrolyte flow 27. Oxygen product gas and electrolyte mixture 28. Hydrogen product gas and electrolyte mixture 29. Cyclone Exit 30. Cyclone surface 31. Gas cleaning container depressurization flow 32. Other gas regulators 33. Gas transport 34. Main pump

Claims

1. A method for preparing feedwater for an alkaline water electrolysis system (1), the alkaline water electrolysis system (1) comprising one or more electrolytic cell stacks (2), wherein, Each of the stacks (2) has at least one diaphragm (3) that separates the oxygen-producing half-cell (4) from the hydrogen-producing half-cell (5), thereby each oxygen-producing half-cell (4) delivers an oxygen-electrolyte mixture (27) and each hydrogen-producing half-cell (5) delivers a hydrogen-electrolyte mixture (28), thereby each mixture is conveyed through pipes to a corresponding separator (23, 24), and in the corresponding separator is separated into a product stream (6) mainly composed of oxygen and an oxygen-deficient electrolyte stream (25), and a product stream (7) mainly composed of hydrogen and a hydrogen-deficient electrolyte stream (26), thereby... The electrolyte flow (25, 26) is supplemented by water from the water supply container (9), and wherein the alkaline water electrolysis system (1) further includes a product gas conditioning system, characterized in that whenever a safety valve (12) is activated, the water supply container (9) receives a blow-out material flow (11) from at least one safety valve (12), and / or whenever the system (1) is depressurized, the water supply container (9) receives a blow-out material flow (31) generated by the depressurization of the pressurized gas cleaning container (21) of the product gas conditioning system, the gas cleaning container (21) containing the product gas (7).

2. The water supply preparation method according to claim 1, wherein, The blown material flow (11, 31) is tangentially guided onto the inner cylindrical surface (14, 15) within the water supply container (9), resulting in the formation of a vortex, whereby possible solids and liquids may precipitate onto the inner cylindrical surface (14, 16), and causing gas to exit the container (9) along an outlet pipe (16) arranged coaxially with the central axis (17) of the inner cylindrical surface (15, 14).

3. The water supply preparation method according to claim 1 or 2, wherein, The water supply container (9) receives alkaline fluid effluent (8) from the process of filtering and drying the corresponding product airflow (6, 7).

4. The water supply preparation method according to any one of claims 1 to 3, wherein, The feed water from the feed water container and any possible alkaline materials dissolved in the feed water are pressurized and used in the product gas cleaning process in the gas cleaning container (21), wherein any possible alkaline substances carried in the product gas stream (6, 7) are dissolved in the pressurized feed water, and further, the alkaline-rich water (13) thereby enters one of the separators (23, 24) to replenish the water lost in the half-cells (5, 6) during electrolysis.

5. The water supply preparation method according to any one of claims 1 to 4, wherein, The first water supply container (9) receives fluid and gas from the hydrogen production system and delivers water to the hydrogen cleaning process. The second water supply container receives fluid and gas from the oxygen production system and delivers water to the oxygen cleaning process.

6. A water preparation system in an alkaline water electrolysis system (1), wherein, The alkaline water electrolysis system (1) is suitable for producing hydrogen and oxygen in one or more pressurized electrolytic cell stacks (2), wherein each stack (2) has at least one diaphragm (3) separating an oxygen-producing half-cell (4) from a hydrogen-producing half-cell (5), thereby each oxygen-producing half-cell (4) is suitable for conveying an oxygen-electrolyte mixture (27), and each hydrogen-producing half-cell (5) is suitable for conveying a hydrogen-electrolyte mixture (28), thereby each mixture is conveyed via pipeline to a corresponding separator (23, 24), and in the corresponding separator The product stream (6) is mainly composed of oxygen and the electrolyte stream (25), and the product stream (7) is mainly composed of hydrogen and the electrolyte stream (26). The electrolyte streams (25, 26) are supplemented by water from the water supply container (9). The alkaline water electrolysis system (1) further includes a product gas conditioning system, characterized in that a safety valve blow-out material flow pipe (11) is connected to the water supply container (9), and / or a pressure-reducing flow pipe (31) from the gas cleaning container (21) of the product gas conditioning system is connected to the water supply container (9).

7. The water preparation system according to claim 6, wherein, The safety valve conduit and the material flow (11) and / or pressure reducing flow conduit (31) are tangentially connected to the cylindrical portions (14, 15) in the water supply container (9) to discharge the material flow (11) along the inner cylindrical surface portion (14, 15) inside the water supply container (9). In addition, the outlet conduit (16) is coaxially arranged with the cylindrical axis of the inner cylindrical surface portion (14, 15) in the water supply container (9) and is directly connected to the atmosphere.

8. The water preparation system according to claim 6 or 7, wherein, The water supply container (9) is connected to the drain pipe (8) of the other gas regulators (32) in the gas preparation system (21, 23, 24, 32).

9. The water preparation system according to any one of claims 6 to 8, wherein, A water outlet pipe (20) from the lower part of the water supply container (9) is connected to a water supply pressure pump (19) and is adapted to supply the water supply material flow (20) to the gas cleaning container (21). In addition, the pipe connects the gas cleaning container and the gas separator (24) to each other, so that water from the water supply container (9) can enter the gas separator (24) in the form of alkaline water flow (13) through the gas cleaning device (21), thereby replenishing the water lost during water electrolysis.

10. The water preparation system according to any one of claims 6 to 9, wherein, The first water supply container (9) is connected to the drain pipe and filter of the hydrogen production system (32) and is also connected to the hydrogen cleaning container (21) for supplying water to the hydrogen cleaning container. The second water supply container is connected to the drain pipe and filter of the oxygen production system and is also connected to the oxygen cleaning container for supplying water to the oxygen cleaning container.

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