Water electrolysis system and cold start method thereof

Abstract

The invention discloses a water electrolysis system which comprises an electrolytic bath, an anode gas-liquid separation tank, a cathode gas-liquid separation tank, an anode main pipeline, a cathode main pipeline and a backflow main pipeline. An anode cavity partition plate is arranged in the anode gas-liquid separation tank to divide an inner cavity of the anode gas-liquid separation tank into an anode low-position cavity and an anode high-position cavity, the anode low-position cavity is communicated with the top of the anode high-position cavity, an anode three-way valve is arranged on the anode gas-liquid separation tank, and one outlet of the anode three-way valve is communicated with the upper portion of the anode low-position cavity. The other outlet is communicated with the upper part of the anode high-position cavity; a cathode cavity partition plate is arranged in the cathode gas-liquid separation tank to divide an inner cavity of the cathode gas-liquid separation tank into a cathode low-position cavity and a cathode high-position cavity, the cathode low-position cavity is communicated with the top of the cathode high-position cavity, a cathode three-way valve is arranged on the cathode gas-liquid separation tank, one outlet of the cathode three-way valve is communicated with the upper portion of the cathode low-position cavity, and the other outlet of the cathode three-way valve is communicated with the lower portion of the cathode high-position and the other outlet is communicated with the upper part of the cathode high-position cavity. The invention further discloses a water electrolysis system cold starting method adopting the water electrolysis system.

Description

Technical Field

[0001] The present invention relates to the technical field of water electrolysis process and its supporting equipment, and in particular to a water electrolysis system. The present invention also relates to a water electrolysis system cold start method used for the water electrolysis system. Background Art

[0002] The existing electrolytic water system is mainly composed of an electrolytic cell and supporting functional devices such as a gas-liquid separation device. During its specific operation, the electrolytic cell electrolyzes the electrolyte to produce hydrogen and oxygen to meet the needs of the corresponding downstream equipment for the use of hydrogen and oxygen during operation.

[0003] In the actual operation of the current electrolytic water system, if the ambient temperature is relatively low, the performance of the electrolytic cell in producing hydrogen and oxygen is relatively low. Under the same hydrogen production, the power required for the operation of the equipment is large and the energy consumption is high compared to the stable operation of the equipment. At the same time, during the operation of the electrolytic water system, the electrolyte usually circulates between the gas-liquid separation device and the electrolytic cell. The heat generation part is the electrolytic cell, and the temperature of the electrolyte has a great influence on the working performance of the electrolytic cell. Accordingly, after the electrolyte system is cold-started, if the overall electrolyte temperature is increased by the heat generation of the electrolytic cell alone, it will take a long time and the equipment power consumption will be high.

[0004] To this end, the more common solution in the industry is to extend the startup time of the electrolytic cell and use the heat generated by the electrolytic cell itself to slowly heat the electrolyte. In this process, not only is the operating pressure of the electrolytic cell high, the working performance is poor, but the heating time is long, which directly leads to the extension of the startup time of the electrolytic water system, restricting the overall operating efficiency of related equipment and production systems.

[0005] In addition, there is a method of using a heater to assist the operation of the electrolysis water system on the market. That is, a heater is connected in series in the electrolyte circulation pipeline in the electrolysis water system. When the electrolysis water system is cold-started, the heater is used to heat the electrolyte so that the temperature of the electrolyte reaches the temperature required by the working condition as soon as possible, thereby matching the operating requirements of the electrolyzer and improving the overall performance of the electrolyzer and the electrolysis water system. However, this method has high requirements for the operating reliability and working condition tolerance of the heater. The newly added heater will make the pipeline layout of the electrolysis water system more complicated, and the energy consumption of the heater itself during operation is also high, resulting in the overall cold start effect of the electrolysis water system is not ideal.

[0006] In view of this, how to make the cold start of the water electrolysis system faster and more efficient and reduce its energy consumption during the cold start process is an important technical problem that technical personnel in this field currently need to solve. Summary of the invention

[0007] The object of the present invention is to provide a water electrolysis system, which can quickly and efficiently achieve cold start, and its energy consumption during the cold start process is low. Another object of the present invention is to provide a water electrolysis system cold start method using the above water electrolysis system.

[0008] In order to solve the above technical problems, the present invention provides a water electrolysis system, comprising an electrolytic cell, an anode gas-liquid separation tank, a cathode gas-liquid separation tank, an anode main line, a cathode main line and a reflux main line;

[0009] The top of the anode gas-liquid separation tank is connected with an oxygen exhaust pipe for exhausting oxygen, and an anode cavity plate extending in the vertical direction is arranged in the anode gas-liquid separation tank. The bottom and the edge portions on both sides of the anode cavity plate are respectively fitted and abutted against the bottom and the inner wall of the side of the anode gas-liquid separation tank to separate the inner cavity of the anode gas-liquid separation tank into an anode low-position cavity and an anode high-position cavity. The top of the anode cavity plate is gap-matched with the inner wall of the top of the anode gas-liquid separation tank to make the anode low-position cavity communicate with the top of the anode high-position cavity. An anode drain port is arranged at the bottom of the anode gas-liquid separation tank, and the anode drain port is connected to the bottom of the anode low-position cavity. An anode three-way valve is arranged on the anode gas-liquid separation tank, and one of the outlet ends of the anode three-way valve is connected to the top of the anode low-position cavity, and the other outlet end is connected to the top of the anode high-position cavity.

[0010] The top of the cathode gas-liquid separation tank is connected with a hydrogen discharge pipe for discharging hydrogen. A cathode partition plate extending in the vertical direction is arranged in the cathode gas-liquid separation tank. The bottom and the edge portions on both sides of the cathode partition plate are respectively fitted against the bottom and the inner wall of the side of the cathode gas-liquid separation tank to separate the inner cavity of the cathode gas-liquid separation tank into a cathode low-position cavity and a cathode high-position cavity. The top of the cathode partition plate is gap-matched with the inner wall of the top of the cathode gas-liquid separation tank to make the cathode low-position cavity communicate with the top of the cathode high-position cavity. A cathode drain port is arranged at the bottom of the cathode gas-liquid separation tank, and the cathode drain port is connected to the bottom of the cathode low-position cavity. A cathode three-way valve is arranged on the cathode gas-liquid separation tank, and one of the outlet ends of the cathode three-way valve is connected to the top of the cathode low-position cavity, and the other outlet end is connected to the top of the cathode high-position cavity.

[0011] The inlet end of the anode main line is connected to the anode discharge port of the electrolytic cell, the outlet end of the anode main line is connected to the inlet end of the anode three-way valve, the inlet end of the cathode main line is connected to the cathode discharge port of the electrolytic cell, and the outlet end of the cathode main line is connected to the inlet end of the cathode three-way valve;

[0012] An anode reflux branch is connected downstream of the anode discharge port, and a cathode reflux branch is connected downstream of the cathode discharge port. Both the anode reflux branch and the cathode reflux branch are connected upstream of the reflux main line, and the anode reflux branch is connected in parallel with the cathode reflux branch. The outlet end of the reflux main line is connected to the reflux inlet of the electrolytic cell.

[0013] Preferably, the main reflux line is provided with a reflux circulation pump for causing the liquid in the main reflux line to flow to the electrolytic cell.

[0014] Preferably, a heat exchanger is provided on the reflux main line.

[0015] Preferably, the heat exchanger is arranged upstream of the reflux circulation pump along the liquid flow direction in the reflux main line.

[0016] Preferably, it also includes an anode liquid level meter that cooperates with the inner cavity of the anode gas-liquid separation tank and a cathode liquid level meter that cooperates with the inner cavity of the cathode gas-liquid separation tank.

[0017] Preferably, the detection end of the anode liquid level gauge is adapted to the anode low-level cavity, and the detection end of the cathode liquid level gauge is adapted to the cathode low-level cavity.

[0018] Preferably, the anode partition plate is detachably mounted in the anode gas-liquid separation tank, and the cathode partition plate is detachably mounted in the cathode gas-liquid separation tank.

[0019] Preferably, an anode return valve is provided on and off the anode return branch, and a cathode return valve is provided on and off the cathode return branch.

[0020] The present invention also provides a cold start method for a water electrolysis system, comprising the steps of:

[0021] Using the water electrolysis system as described in any one of the above items, when the water electrolysis system is started from a cold state, the outlet end of the anode three-way valve connected to the anode low-position cavity is kept open, and the outlet end of the anode three-way valve connected to the anode high-position cavity is kept closed, and at the same time, the outlet end of the cathode three-way valve connected to the cathode low-position cavity is kept open, and the outlet end of the cathode three-way valve connected to the cathode high-position cavity is kept closed;

[0022] The electrolytic cell is started. After the electrolytic cell electrolyzes the electrolyte inside, the electrolyte mixed with oxygen generated at the anode of the electrolytic cell is discharged through the anode discharge port of the electrolytic cell, and then transported to the anode low-position cavity through the anode main line and the anode three-way valve in sequence. These electrolytes are appropriately accumulated and allowed to stand in the anode low-position cavity to allow the oxygen mixed therein to escape. The escaped oxygen is discharged through the oxygen discharge pipe to meet the needs of the operation of the downstream oxygen-using equipment. The electrolyte in the anode low-position cavity has been heated to a higher temperature by the electrolysis treatment of the electrolytic cell, so it can be mixed with the original stored liquid in the anode low-position cavity, thereby rapidly increasing the liquid temperature in the anode low-position cavity;

[0023] At the same time, the electrolyte mixed with hydrogen generated at the cathode of the electrolyzer is discharged through the cathode discharge port of the electrolyzer, and then transported to the cathode low-level cavity through the cathode main pipeline and the cathode three-way valve in sequence. These electrolytes are appropriately accumulated and left to stand in the cathode low-level cavity to allow the hydrogen mixed therein to escape. The escaped hydrogen is discharged through the hydrogen discharge pipe to meet the needs of the operation of downstream hydrogen-using equipment. The electrolyte in the cathode low-level cavity has been heated to a higher temperature by the electrolysis treatment of the electrolyzer, so it can be mixed with the original stored liquid in the cathode low-level cavity, thereby rapidly increasing the liquid temperature in the cathode low-level cavity;

[0024] After the electrolysis water system has been running as a whole for a period of time, the liquid temperature in the anode low-level cavity and the cathode low-level cavity has risen to a temperature that meets the working condition requirements. At this time, the outlet end of the anode three-way valve connected to the anode high-level cavity and the outlet end of the cathode three-way valve connected to the cathode high-level cavity are opened respectively, so that the electrolyte discharged from the electrolytic cell and heated after electrolysis treatment is respectively passed into the anode high-level cavity and the cathode high-level cavity, until the liquid level of any one of the anode high-level cavity and the anode low-level cavity in the anode gas-liquid separation tank exceeds the upper edge of the anode partition plate, and the liquid level of any one of the cathode high-level cavity and the cathode low-level cavity in the cathode gas-liquid separation tank exceeds the upper edge of the cathode partition plate, thereby achieving liquid conduction between the anode low-level cavity and the anode high-level cavity and liquid conduction between the cathode low-level cavity and the cathode high-level cavity, and then completing the mixing and heating of the liquid in the entire anode gas-liquid separation tank cavity and the mixing and heating of the liquid in the entire cathode gas-liquid separation tank cavity, respectively, to match the current working condition requirements;

[0025] After the electrolytic cell is started, the electrolyte in the anode gas-liquid separation tank is discharged through the anode drain port, and then transported to the inside of the electrolytic cell for recycling through the anode reflux branch, the reflux main line and the reflux inlet in sequence, while the electrolyte in the cathode gas-liquid separation tank is discharged through the cathode drain port, and then transported to the inside of the electrolytic cell for recycling through the cathode reflux branch, the reflux main line and the reflux inlet in sequence.

[0026] Preferably, when the liquids of the anode high-position cavity and the anode low-position cavity are in conduction and the liquid temperature in the anode gas-liquid separation tank has reached the working condition requirement, the outlet end of the anode three-way valve connected to the anode low-position cavity is closed, and the outlet end of the anode three-way valve connected to the anode high-position cavity is kept open;

[0027] When the liquid in the cathode high-level cavity is connected to the cathode low-level cavity and the liquid temperature in the cathode gas-liquid separation tank has reached the operating requirements, close the outlet end of the cathode three-way valve connected to the cathode low-level cavity, and keep the outlet end of the cathode three-way valve connected to the cathode high-level cavity open.

[0028] Compared with the above-mentioned background technology, during the operation of the electrolysis water system provided by the present invention, when it is necessary to cold-start the electrolysis water system in a shutdown state, the outlet end of the anode three-way valve connected to the anode low-position cavity is kept open, and the outlet end of the anode three-way valve connected to the anode high-position cavity is kept closed, and at the same time, the outlet end of the cathode three-way valve connected to the cathode low-position cavity is kept open, and the outlet end of the cathode three-way valve connected to the cathode high-position cavity is kept closed. After that, the electrolytic cell can be started. After the electrolytic cell electrolyzes the electrolyte inside it, the electrolyte mixed with oxygen generated at the anode of the electrolytic cell is discharged through the anode discharge port of the electrolytic cell, and is transported to the anode low-level cavity through the anode main line and the anode three-way valve in sequence. These electrolytes are appropriately accumulated and allowed to stand still in the anode low-level cavity to allow the oxygen mixed therein to escape. The escaped oxygen is discharged through the oxygen discharge pipe to meet the needs of the operation of the downstream oxygen-using equipment. The electrolyte in the anode low-level cavity has been heated to a higher temperature due to the electrolysis treatment of the electrolytic cell, so it can be mixed with the original stored liquid in the anode low-level cavity, thereby heating the anode low-level cavity. The temperature of the liquid in the cavity rises rapidly; at the same time, the electrolyte mixed with hydrogen generated at the cathode of the electrolytic cell is discharged through the cathode discharge port of the electrolytic cell, and is transported to the cathode low-level cavity through the cathode main line and the cathode three-way valve in turn. These electrolytes are appropriately accumulated and allowed to stand still in the cathode low-level cavity to allow the hydrogen mixed therein to escape, and the escaped hydrogen is discharged through the hydrogen discharge pipe to meet the needs of the operation of downstream hydrogen-using equipment. The electrolyte in the cathode low-level cavity has been heated to a higher temperature due to the electrolysis treatment of the electrolytic cell, so it can be mixed with the original liquid in the cathode low-level cavity, thereby rapidly raising the temperature of the liquid in the cathode low-level cavity. After the electrolysis water system has been running as a whole for a period of time, the liquid temperature in the anode low-level cavity and the cathode low-level cavity has risen to a temperature that meets the working condition requirements. At this time, the outlet end of the anode three-way valve connected to the anode high-level cavity and the outlet end of the cathode three-way valve connected to the cathode high-level cavity are opened respectively, so that the electrolyte discharged from the electrolytic cell and heated after electrolysis treatment is respectively passed into the anode high-level cavity and the cathode high-level cavity, until the liquid level of any one of the anode high-level cavity and the anode low-level cavity in the anode gas-liquid separation tank exceeds the upper edge of the anode partition plate, and the liquid level of any one of the cathode high-level cavity and the cathode low-level cavity in the cathode gas-liquid separation tank exceeds the upper edge of the cathode partition plate, thereby achieving liquid conduction between the anode low-level cavity and the anode high-level cavity and liquid conduction between the cathode low-level cavity and the cathode high-level cavity, and then completing the mixing and heating of the liquid in the entire anode gas-liquid separation tank cavity and the mixing and heating of the liquid in the entire cathode gas-liquid separation tank cavity, respectively, to match the current working condition requirements.Correspondingly, after the electrolyzer is started, the electrolyte in the anode gas-liquid separator tank is discharged through the anode discharge port, and then transported to the inside of the electrolyzer for recycling through the anode reflux branch, the reflux main line and the reflux inlet in sequence, while the electrolyte in the cathode gas-liquid separator tank is discharged through the cathode discharge port, and then transported to the inside of the electrolyzer for recycling through the cathode reflux branch, the reflux main line and the reflux inlet in sequence. During the cold start process of the electrolytic water system, no third-party energy-consuming devices such as heat exchangers are required to participate, and there is no need for high-load operation of the electrolytic cell, so the cold start can be completed smoothly and efficiently, thereby greatly reducing the energy consumption during the cold start process of the electrolytic water system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 A schematic diagram of the component layout of a water electrolysis system provided in a specific embodiment of the present invention.

[0031] in:

[0032] 10-electrolytic cell; 101-anode discharge port; 102-cathode discharge port; 103-reflux liquid inlet;

[0033] 11-anode gas-liquid separation tank; 111-oxygen exhaust pipe; 112-anode compartment plate; 113-anode low-position cavity; 114-anode high-position cavity; 115-anode liquid discharge port; 116-anode liquid level gauge;

[0034] 12- cathode gas-liquid separation tank; 121- hydrogen discharge pipe; 122- cathode partition plate; 123- cathode low-level cavity; 124- cathode high-level cavity; 125- cathode liquid discharge port; 126- cathode liquid level gauge;

[0035] 13-anode main pipeline; 131-anode three-way valve;

[0036] 14- cathode main line; 141- cathode three-way valve;

[0037] 15- reflux main line; 151- anode reflux branch; 152- cathode reflux branch; 153- reflux circulation pump; 154- heat exchanger; 155- anode reflux valve; 156- cathode reflux valve. DETAILED DESCRIPTION

[0038] The core of the present invention is to provide an electrolytic water system, which can quickly and efficiently achieve cold start, and its energy consumption during the cold start process is low; and also provides an electrolytic water system cold start method using the above electrolytic water system.

[0039] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0040] Please refer to Figure 1 , Figure 1 A schematic diagram of the component layout of a water electrolysis system provided in a specific embodiment of the present invention.

[0041] In a specific embodiment, the water electrolysis system provided by the present invention includes an electrolytic cell 10 , an anode gas-liquid separation tank 11 , a cathode gas-liquid separation tank 12 , an anode main line 13 , a cathode main line 14 and a reflux main line 15 .

[0042] The top of the anode gas-liquid separation tank 11 is connected to an oxygen exhaust pipe 111 for exhausting oxygen. The anode gas-liquid separation tank 11 is provided with an anode compartment plate 112 extending in the vertical direction. The bottom and both side edges of the anode compartment plate 112 are respectively fitted against the bottom and side inner walls of the anode gas-liquid separation tank 11 to separate the inner cavity of the anode gas-liquid separation tank 11 into an anode low-position cavity 113 and an anode high-position cavity 114. The top of the anode compartment plate 112 is in contact with the anode gas-liquid separation tank 11. 1, so that the anode low-position cavity 113 is connected to the top of the anode high-position cavity 114. The bottom of the anode gas-liquid separation tank 11 is provided with an anode drain port 115, and the anode drain port 115 is connected to the bottom of the anode low-position cavity 113. The anode gas-liquid separation tank 11 is provided with an anode three-way valve 131, one of the outlet ends of the anode three-way valve 131 is connected to the top of the anode low-position cavity 113, and the other outlet end is connected to the top of the anode high-position cavity 114.

[0043] The top of the cathode gas-liquid separation tank 12 is connected to a hydrogen discharge pipe 121 for discharging hydrogen. A cathode partition plate 122 extending in the vertical direction is provided in the cathode gas-liquid separation tank 12. The bottom and the edges on both sides of the cathode partition plate 122 are respectively fitted against the bottom and the inner wall of the side of the cathode gas-liquid separation tank 12 to separate the inner cavity of the cathode gas-liquid separation tank 12 into a cathode low-position cavity 123 and a cathode high-position cavity 124. The top of the cathode partition plate 122 is fitted against the cathode gas-liquid separation tank 12. The top inner wall clearance is matched so that the cathode low-position cavity 123 is connected with the top of the cathode high-position cavity 124. A cathode drain port 125 is provided at the bottom of the cathode gas-liquid separation tank 12, and the cathode drain port 125 is connected to the bottom of the cathode low-position cavity 123. A cathode three-way valve 141 is provided on the cathode gas-liquid separation tank 12, and one of the outlet ends of the cathode three-way valve 141 is connected to the top of the cathode low-position cavity 123, and the other outlet end is connected to the top of the cathode high-position cavity 124.

[0044] Correspondingly, the inlet end of the anode main line 13 is connected to the anode discharge port 101 of the electrolytic cell 10, the outlet end of the anode main line 13 is connected to the inlet end of the anode three-way valve 131, the inlet end of the cathode main line 14 is connected to the cathode discharge port 102 of the electrolytic cell 10, and the outlet end of the cathode main line 14 is connected to the inlet end of the cathode three-way valve 141;

[0045] In addition, the downstream of the anode discharge port 115 is connected to an anode reflux branch 151, and the downstream of the cathode discharge port 125 is connected to a cathode reflux branch 152. The anode reflux branch 151 and the cathode reflux branch 152 are both connected to the upstream of the reflux main line 15, and the anode reflux branch 151 is connected in parallel with the cathode reflux branch 152. The outlet end of the reflux main line 15 is connected to the reflux inlet 103 of the electrolytic cell 10.

[0046] During the operation of the equipment, when it is necessary to cold-start the electrolytic water system in a shutdown state, the outlet end of the anode three-way valve 131 connected to the anode low-level cavity 113 is kept open, and the outlet end of the anode three-way valve 131 connected to the anode high-level cavity 114 is kept closed, and at the same time, the outlet end of the cathode three-way valve 141 connected to the cathode low-level cavity 123 is kept open, and the outlet end of the cathode three-way valve 141 connected to the cathode high-level cavity 124 is kept closed.

[0047] Thereafter, the electrolytic cell 10 can be started. After the electrolytic cell 10 electrolyzes the electrolyte inside it, the electrolyte mixed with oxygen generated at the anode of the electrolytic cell 10 is discharged through the anode discharge port 101 of the electrolytic cell 10, and then transported to the anode low-level chamber 113 through the anode main pipeline 13 and the anode three-way valve 131 in sequence. These electrolytes are appropriately accumulated and allowed to stand still in the anode low-level chamber 113 to allow the oxygen mixed therein to escape. The escaped oxygen is discharged through the oxygen discharge pipe 111 to facilitate the operation of downstream oxygen-using equipment. The electrolyte in the anode low-level chamber 113 has been heated to a higher temperature due to the electrolysis treatment of the electrolytic cell 10, so it can be mixed with the original stored liquid in the anode low-level chamber 113, thereby rapidly increasing the liquid temperature in the anode low-level chamber 113. At the same time, the electrolyte mixed with hydrogen generated at the cathode of the electrolytic cell 10 is discharged through the cathode discharge port 102 of the electrolytic cell 10, and is transported to the cathode low-level cavity 123 through the cathode main pipeline 14 and the cathode three-way valve 141 in sequence. These electrolytes are appropriately accumulated and allowed to stand still in the cathode low-level cavity 123 to allow the hydrogen mixed therein to escape. The escaped hydrogen is discharged through the hydrogen discharge pipe 121 to facilitate the operation of downstream hydrogen-using equipment. The electrolyte in the cathode low-level cavity 123 has been heated to a higher temperature by the electrolysis treatment of the electrolytic cell 10, so it can be mixed with the original stored liquid in the cathode low-level cavity 123, thereby rapidly increasing the liquid temperature in the cathode low-level cavity 123.

[0048] After the electrolysis water system has been running for a period of time, the liquid temperature in the anode low-level chamber 113 and the cathode low-level chamber 123 has risen to a temperature that meets the working condition requirements. At this time, the outlet end of the anode three-way valve 131 connected to the anode high-level chamber 114 and the outlet end of the cathode three-way valve 141 connected to the cathode high-level chamber 124 are opened respectively, so that the electrolyte discharged from the electrolytic cell 10 and heated after electrolysis treatment is respectively passed into the anode high-level chamber 114 and the cathode high-level chamber 124 until the anode high-level chamber 114 and the anode low-level chamber 113 in the anode gas-liquid separation tank 11 are connected. 3, the liquid level of any one of them exceeds the upper edge of the anode cavity plate 112, and the liquid level of any one of the cathode high-level cavity 124 and the cathode low-level cavity 123 in the cathode gas-liquid separation tank 12 exceeds the upper edge of the cathode cavity plate 122, thereby realizing liquid conduction between the anode low-level cavity 113 and the anode high-level cavity 114, and liquid conduction between the cathode low-level cavity 123 and the cathode high-level cavity 124, and then completing the mixing and heating of the liquid in the inner cavity of the entire anode gas-liquid separation tank 11 and the mixing and heating of the liquid in the inner cavity of the entire cathode gas-liquid separation tank 12, respectively, to match the current working conditions.

[0049] Accordingly, after the electrolytic cell 10 is started, the electrolyte in the anode gas-liquid separation tank 11 is discharged through the anode drain port 115, and then transported to the inside of the electrolytic cell 10 for recycling via the anode reflux branch 151, the reflux main line 15 and the reflux inlet 103 in sequence, while the electrolyte in the cathode gas-liquid separation tank 12 is discharged through the cathode drain port 125, and then transported to the inside of the electrolytic cell 10 for recycling via the cathode reflux branch 152, the reflux main line 15 and the reflux inlet 103 in sequence.

[0050] It is not difficult to understand that the cold start of the electrolytic water system mentioned herein refers to the electrolytic water system after a long period of shutdown, the temperature of the electrolyte in its system is low, and the supporting electrolyzer 10 and other functional devices are also in the cold machine working condition after a long period of shutdown. In this cold machine condition, the electrolytic water system is attempted to be started as a whole to resume operation, which is the cold start of the electrolytic water system. Correspondingly, there is also a hot start working condition of the electrolytic water system, that is, the electrolytic water in the electrolytic water system still has a higher residual temperature after a short shutdown, which is enough to meet the working condition temperature demand when the equipment is operating normally, and the supporting electrolyzer 10 and other functional devices have only been shut down for a short time, and are still in the hot machine working condition. In this case, the electrolytic water system is attempted to be started as a whole to resume operation, which is the hot start process of the electrolytic water system. In fact, the above-mentioned cold start and hot start working conditions are relatively conventional technical concepts for those skilled in the art, and only need to refer to the corresponding understanding of conventional technology in the industry, and will not be repeated.

[0051] Generally, a main water supply pipeline matching the electrolytic cell 10 will also be arranged in the electrolysis water system. When the equipment is actually running, the electrolyte is transported to the electrolytic cell 10 through the main water supply pipeline, which serves as the main supply source of the electrolyte in the electrolytic cell 10 to ensure the electrolysis operation of the electrolytic cell 10 and the corresponding working conditions. A main water inlet corresponding to the main water supply pipeline will be arranged on the electrolytic cell 10 to ensure that the electrolyte sent from the main water supply pipeline flows smoothly into the electrolytic cell 10. In fact, the main water supply pipeline and its supporting connecting structure and arrangement method related to the electrolytic cell 10 belong to the conventional technology in this field. This solution does not involve subversive improvements to the component structure and device function here. Therefore, the relevant technical content here can be understood with reference to the corresponding conventional technical solutions in this field, and this article will not repeat them.

[0052] Accordingly, the electrolyte mentioned in this scheme is generally an alkaline solution widely used in the industry. For this field, the electrolyte is usually a potassium hydroxide electrolyte. For this scheme, the type of electrolyte used in the electrolyte system can also be flexibly selected and adjusted by referring to the conventional technical means in the industry and combining the actual application conditions of this scheme. In principle, as long as it can meet the working requirements of functional devices such as the electrolytic cell 10 and ensure the normal operation of the water electrolysis system.

[0053] Specifically, the reflux main line 15 is provided with a reflux circulation pump 153 for allowing the liquid in the reflux main line 15 to flow to the electrolytic cell 10. The reflux circulation pump 153 can serve as a power source for the circulation of the liquid in the reflux main line 15 to further optimize the circulation effect of the liquid in the reflux main line 15. Considering the systematic connection structure between the reflux main line 15 and each gas-liquid separation tank and the supporting pipelines, the pumping action of the reflux circulation pump 153 on the reflux main line 15 can also make the overall circulation of the liquid in each pipeline of the electrolytic water system smoother and more efficient.

[0054] Furthermore, a heat exchanger 154 is provided on the reflux main line 15. After the water electrolysis system is started up as a whole and runs smoothly, if the temperature of the electrolyte in the reflux main line 15 is high and exceeds the operating temperature required for the normal operation of the electrolytic cell 10, the heat exchanger 154 can be started, and the coolant circulating in the heat exchanger 154 is used to exchange heat with the electrolyte flowing through the heat exchanger 154, so as to reduce the temperature of the electrolyte flowing through the heat exchanger 154 to meet the normal operation requirements of the downstream functional devices such as the electrolytic cell 10, thereby matching the overall operating application conditions of the water electrolysis system and ensuring the smooth operation of the water electrolysis system.

[0055] Accordingly, the heat exchanger 154 can directly adopt a conventional heat exchange device used in the prior art in this field. In principle, as long as it can effectively cool the high-temperature electrolyte in the return main line 15 to ensure the normal and stable operation of the water electrolysis system.

[0056] Furthermore, the heat exchanger 154 is usually arranged upstream of the reflux circulation pump 153 along the direction of liquid flow in the reflux main line 15. In this way, the heat exchanger 154 can be arranged in the upstream position of the reflux main line 15 as much as possible, so as to cool the high-temperature electrolyte entering the reflux main line 15 as soon as possible, so as to prevent the high-temperature electrolyte from causing adverse effects on most of the piping structures of the reflux main line 15 and the downstream functional devices such as the reflux circulation pump 153, thereby further optimizing the cooling effect of the electrolyte in the reflux main line 15, and optimizing the working condition matching effect and protection effect of the downstream functional devices such as the electrolytic cell 10.

[0057] On the other hand, the electrolytic water system also includes an anode liquid level gauge 116 that cooperates with the inner cavity of the anode gas-liquid separation tank 11 and a cathode liquid level gauge 126 that cooperates with the inner cavity of the cathode gas-liquid separation tank 12. During the operation of the equipment, especially during a period of time from the cold start of the electrolytic water system to the time when it can operate smoothly, the staff can respectively understand the liquid level status in the anode gas-liquid separation tank 11 and the cathode gas-liquid separation tank 12 in real time through the anode liquid level gauge 116 and the cathode liquid level gauge 126, so as to timely adjust the conduction status of the corresponding pipelines and the operating status of related functional devices, so as to match the overall operation requirements of the electrolytic water system and ensure the efficient transportation of the electrolyte and the smooth operation of the electrolyte system.

[0058] More specifically, the detection end of the anode liquid level gauge 116 is adapted to the anode low-level cavity 113, and the detection end of the cathode liquid level gauge 126 is adapted to the cathode low-level cavity 123. The corresponding adaptation of each liquid level gauge to the low-level cavity of the corresponding gas-liquid separation tank is helpful to more accurately and intuitively understand the liquid level state at the anode low-level cavity 113 and the cathode low-level cavity 123, so that the electrolyte state in the corresponding low-level cavity in each gas-liquid separation tank can be timely understood during the cold start of the electrolyzed water system, so that the staff can accurately grasp the current overall operation state of the system, so as to timely determine whether the current system operation has smoothly completed the cold start, and determine whether it can be transferred to the normal system operation state, so as to timely adjust the conduction and closing state of each three-way valve and the corresponding pipeline, so as to match the smooth operation requirements of each functional device in the system.

[0059] Correspondingly, thermometers will be arranged at the anode low-level cavity 113 and the cathode low-level cavity 123 respectively to monitor the liquid temperature in the anode low-level cavity 113 and the cathode low-level cavity 123, so as to timely adjust the conduction and operation status of each pipeline and device, so as to match the cold start and stable operation working condition requirements of the electrolysis water system. Generally, the thermometers matched at each low-level cavity can be arranged in conjunction with the corresponding anode liquid level gauge 116 and cathode liquid level gauge 126 to further optimize the arrangement structure of the supporting components of each gas-liquid separation tank, so that the device layout of the electrolysis water system is more regular and compact.

[0060] In addition, the anode cavity plate 112 is disassembled and arranged in the anode gas-liquid separation tank 11, and the cathode cavity plate 122 is disassembled and arranged in the cathode gas-liquid separation tank 12. This disassembly and assembly structure can make the arrangement structure of each cavity plate more flexible and changeable. In particular, when the working conditions are adjusted or changed, the original anode cavity plate 112 and cathode cavity plate 122 can be removed to replace the anode cavity plate 112 and cathode cavity plate 122 with higher or lower height dimensions, thereby realizing the adjustment of the isolation conditions and connection time between the low-level cavity and the high-level cavity in each gas-liquid separation tank to match the corresponding system operating conditions and working conditions.

[0061] In addition, after the water electrolysis system completes cold start and enters a stable operating state, each partition plate can be removed from the corresponding gas-liquid separation tank to make the high-level cavity and the low-level cavity in each gas-liquid separation tank fully conductive, thereby making the liquid flow in the corresponding gas-liquid separation tank smoother and more efficient, thereby optimizing the circulation effect of the electrolyte in the water electrolysis system.

[0062] In addition, an anode return valve 155 is provided on and off the anode return branch 151, and a cathode return valve 156 is provided on and off the cathode return branch 152. After the electrolysis water system is cold started, the anode return valve 155 and the cathode return valve 156 can be kept closed to allow the liquid in the anode low-level cavity 113 and the cathode low-level cavity 123 to continue to mix with the continuously supplied high-temperature electrolyte until the liquid temperature in each low-level cavity meets the working condition requirements for the smooth operation of the system, and then the corresponding return valve is opened to ensure the smooth and normal operation of the electrolysis water system.

[0063] In a specific embodiment, the cold start method of the water electrolysis system provided by the present invention comprises the steps of:

[0064] When the water electrolysis system as described above is started from a cold state, the outlet end of the anode three-way valve 131 connected to the anode low-level cavity 113 is kept open, and the outlet end of the anode three-way valve 131 connected to the anode high-level cavity 114 is kept closed, while the outlet end of the cathode three-way valve 141 connected to the cathode low-level cavity 123 is kept open, and the outlet end of the cathode three-way valve 141 connected to the cathode high-level cavity 124 is kept closed.

[0065] Thereafter, the electrolytic cell 10 can be started. After the electrolytic cell 10 electrolyzes the electrolyte inside it, the electrolyte mixed with oxygen generated at the anode of the electrolytic cell 10 is discharged through the anode discharge port 101 of the electrolytic cell 10, and then transported to the anode low-level chamber 113 through the anode main pipeline 13 and the anode three-way valve 131 in sequence. These electrolytes are appropriately accumulated and allowed to stand still in the anode low-level chamber 113 to allow the oxygen mixed therein to escape. The escaped oxygen is discharged through the oxygen discharge pipe 111 to facilitate the operation of downstream oxygen-using equipment. The electrolyte in the anode low-level chamber 113 has been heated to a higher temperature due to the electrolysis treatment of the electrolytic cell 10, so it can be mixed with the original stored liquid in the anode low-level chamber 113, thereby rapidly increasing the liquid temperature in the anode low-level chamber 113.

[0066] At the same time, the electrolyte mixed with hydrogen generated at the cathode of the electrolytic cell 10 is discharged through the cathode discharge port 102 of the electrolytic cell 10, and is transported to the cathode low-level cavity 123 through the cathode main pipeline 14 and the cathode three-way valve 141 in sequence. These electrolytes are appropriately accumulated and allowed to stand still in the cathode low-level cavity 123 to allow the hydrogen mixed therein to escape. The escaped hydrogen is discharged through the hydrogen discharge pipe 121 to facilitate the operation of downstream hydrogen-using equipment. The electrolyte in the cathode low-level cavity 123 has been heated to a higher temperature by the electrolysis treatment of the electrolytic cell 10, so it can be mixed with the original stored liquid in the cathode low-level cavity 123, thereby rapidly increasing the liquid temperature in the cathode low-level cavity 123.

[0067] After the electrolysis water system has been running for a period of time, the liquid temperature in the anode low-level chamber 113 and the cathode low-level chamber 123 has risen to a temperature that meets the working condition requirements. At this time, the outlet end of the anode three-way valve 131 connected to the anode high-level chamber 114 and the outlet end of the cathode three-way valve 141 connected to the cathode high-level chamber 124 are opened respectively, so that the electrolyte discharged from the electrolytic cell 10 and heated after electrolysis treatment is respectively passed into the anode high-level chamber 114 and the cathode high-level chamber 124 until the anode high-level chamber 114 and the anode low-level chamber 113 in the anode gas-liquid separation tank 11 are connected. 3, the liquid level of any one of them exceeds the upper edge of the anode cavity plate 112, and the liquid level of any one of the cathode high-level cavity 124 and the cathode low-level cavity 123 in the cathode gas-liquid separation tank 12 exceeds the upper edge of the cathode cavity plate 122, thereby realizing liquid conduction between the anode low-level cavity 113 and the anode high-level cavity 114, and liquid conduction between the cathode low-level cavity 123 and the cathode high-level cavity 124, and then completing the mixing and heating of the liquid in the inner cavity of the entire anode gas-liquid separation tank 11 and the mixing and heating of the liquid in the inner cavity of the entire cathode gas-liquid separation tank 12, respectively, to match the current working conditions.

[0068] After the electrolytic cell 10 is started, the electrolyte in the anode gas-liquid separation tank 11 is discharged through the anode drain port 115, and then transported to the inside of the electrolytic cell 10 for recycling through the anode reflux branch 151, the reflux main line 15 and the reflux inlet 103 in sequence, while the electrolyte in the cathode gas-liquid separation tank 12 is discharged through the cathode drain port 125, and then transported to the inside of the electrolytic cell 10 for recycling through the cathode reflux branch 152, the reflux main line 15 and the reflux inlet 103 in sequence.

[0069] The cold start method of the water electrolysis system has a fast and efficient start-up process, and does not require the participation of third-party energy-consuming devices such as the heat exchanger 154, nor does it require high-load operation of the electrolytic cell 10, thereby greatly reducing the energy consumption during the cold start of the water electrolysis system.

[0070] In actual applications, when the liquid in the anode high-level cavity 114 is connected to the anode low-level cavity 113 and the liquid temperature in the anode gas-liquid separation tank 11 has reached the operating requirements, the outlet end of the anode three-way valve 131 connected to the anode low-level cavity 113 is closed, and the outlet end of the anode three-way valve 131 connected to the anode high-level cavity 114 is kept open, so that the liquid in the entire inner cavity of the anode gas-liquid separation tank 11 can smoothly participate in the circulation operation of the electrolysis water system, thereby ensuring the smooth and efficient operation of the electrolysis water system.

[0071] When the liquid in the cathode high-level cavity 124 is connected to the cathode low-level cavity 123 and the liquid temperature in the cathode gas-liquid separation tank 12 has reached the operating condition requirements, close the outlet end of the cathode three-way valve 141 connected to the cathode low-level cavity 123, and keep the outlet end of the cathode three-way valve 141 connected to the cathode high-level cavity 124 open, so that the liquid in the entire inner cavity of the cathode gas-liquid separation tank 12 can smoothly participate in the circulation operation of the electrolysis water system, thereby ensuring the smooth and efficient operation of the electrolysis water system.

[0072] In summary, it can be seen that during the operation of the electrolysis water system provided in the present invention, when it is necessary to cold-start the electrolysis water system in a shutdown state, the outlet end of the anode three-way valve connected to the anode low-position cavity is kept open, and the outlet end of the anode three-way valve connected to the anode high-position cavity is kept closed, and at the same time, the outlet end of the cathode three-way valve connected to the cathode low-position cavity is kept open, and the outlet end of the cathode three-way valve connected to the cathode high-position cavity is kept closed. After that, the electrolytic cell can be started. After the electrolytic cell electrolyzes the electrolyte inside it, the electrolyte mixed with oxygen generated at the anode of the electrolytic cell is discharged through the anode discharge port of the electrolytic cell, and is transported to the anode low-level cavity through the anode main line and the anode three-way valve in sequence. These electrolytes are appropriately accumulated and allowed to stand still in the anode low-level cavity to allow the oxygen mixed therein to escape. The escaped oxygen is discharged through the oxygen discharge pipe to meet the needs of the operation of the downstream oxygen-using equipment. The electrolyte in the anode low-level cavity has been heated to a higher temperature due to the electrolysis treatment of the electrolytic cell, so it can be mixed with the original stored liquid in the anode low-level cavity, thereby heating the anode low-level cavity. The temperature of the liquid in the cavity rises rapidly; at the same time, the electrolyte mixed with hydrogen generated at the cathode of the electrolytic cell is discharged through the cathode discharge port of the electrolytic cell, and is transported to the cathode low-level cavity through the cathode main line and the cathode three-way valve in turn. These electrolytes are appropriately accumulated and allowed to stand still in the cathode low-level cavity to allow the hydrogen mixed therein to escape, and the escaped hydrogen is discharged through the hydrogen discharge pipe to meet the needs of the operation of downstream hydrogen-using equipment. The electrolyte in the cathode low-level cavity has been heated to a higher temperature due to the electrolysis treatment of the electrolytic cell, so it can be mixed with the original liquid in the cathode low-level cavity, thereby rapidly raising the temperature of the liquid in the cathode low-level cavity. After the electrolysis water system has been running as a whole for a period of time, the liquid temperature in the anode low-level cavity and the cathode low-level cavity has risen to a temperature that meets the working condition requirements. At this time, the outlet end of the anode three-way valve connected to the anode high-level cavity and the outlet end of the cathode three-way valve connected to the cathode high-level cavity are opened respectively, so that the electrolyte discharged from the electrolytic cell and heated after electrolysis treatment is respectively passed into the anode high-level cavity and the cathode high-level cavity, until the liquid level of any one of the anode high-level cavity and the anode low-level cavity in the anode gas-liquid separation tank exceeds the upper edge of the anode partition plate, and the liquid level of any one of the cathode high-level cavity and the cathode low-level cavity in the cathode gas-liquid separation tank exceeds the upper edge of the cathode partition plate, thereby achieving liquid conduction between the anode low-level cavity and the anode high-level cavity and liquid conduction between the cathode low-level cavity and the cathode high-level cavity, and then completing the mixing and heating of the liquid in the entire anode gas-liquid separation tank cavity and the mixing and heating of the liquid in the entire cathode gas-liquid separation tank cavity, respectively, to match the current working condition requirements.Correspondingly, after the electrolyzer is started, the electrolyte in the anode gas-liquid separator tank is discharged through the anode discharge port, and then transported to the inside of the electrolyzer for recycling through the anode reflux branch, the reflux main line and the reflux inlet in sequence, while the electrolyte in the cathode gas-liquid separator tank is discharged through the cathode discharge port, and then transported to the inside of the electrolyzer for recycling through the cathode reflux branch, the reflux main line and the reflux inlet in sequence. During the cold start process of the electrolytic water system, no third-party energy-consuming devices such as heat exchangers are required to participate, and there is no need for high-load operation of the electrolytic cell, so the cold start can be completed smoothly and efficiently, thereby greatly reducing the energy consumption during the cold start process of the electrolytic water system.

[0073] In addition, the cold start method of the water electrolysis system provided in the present invention using the above-mentioned water electrolysis system has a fast and efficient start-up process, and does not require the participation of third-party energy-consuming devices such as heat exchangers during the cold start process, nor does it require high-load operation of the electrolytic cell, thereby greatly reducing the energy consumption during the cold start process of the water electrolysis system.

[0074] The above is a detailed introduction to the electrolysis water system provided by the present invention and the cold start method of the electrolysis water system using the electrolysis water system. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A water electrolysis system, characterized in that: It includes an electrolytic cell, an anode gas-liquid separation tank, a cathode gas-liquid separation tank, an anode main line, a cathode main line and a reflux main line; The top of the anode gas-liquid separation tank is connected with an oxygen exhaust pipe for exhausting oxygen, and an anode cavity plate extending in the vertical direction is arranged in the anode gas-liquid separation tank. The bottom and the edge portions on both sides of the anode cavity plate are respectively fitted and abutted against the bottom and the inner wall of the side of the anode gas-liquid separation tank to separate the inner cavity of the anode gas-liquid separation tank into an anode low-position cavity and an anode high-position cavity. The top of the anode cavity plate is gap-matched with the inner wall of the top of the anode gas-liquid separation tank to make the anode low-position cavity communicate with the top of the anode high-position cavity. An anode drain port is arranged at the bottom of the anode gas-liquid separation tank, and the anode drain port is connected to the bottom of the anode low-position cavity. An anode three-way valve is arranged on the anode gas-liquid separation tank, and one of the outlet ends of the anode three-way valve is connected to the top of the anode low-position cavity, and the other outlet end is connected to the top of the anode high-position cavity. The top of the cathode gas-liquid separation tank is connected with a hydrogen discharge pipe for discharging hydrogen. A cathode partition plate extending in the vertical direction is arranged in the cathode gas-liquid separation tank. The bottom and the edge portions on both sides of the cathode partition plate are respectively fitted against the bottom and the inner wall of the side of the cathode gas-liquid separation tank to separate the inner cavity of the cathode gas-liquid separation tank into a cathode low-position cavity and a cathode high-position cavity. The top of the cathode partition plate is gap-matched with the inner wall of the top of the cathode gas-liquid separation tank to make the cathode low-position cavity communicate with the top of the cathode high-position cavity. A cathode drain port is arranged at the bottom of the cathode gas-liquid separation tank, and the cathode drain port is connected to the bottom of the cathode low-position cavity. A cathode three-way valve is arranged on the cathode gas-liquid separation tank, and one of the outlet ends of the cathode three-way valve is connected to the top of the cathode low-position cavity, and the other outlet end is connected to the top of the cathode high-position cavity. The inlet end of the anode main line is connected to the anode discharge port of the electrolytic cell, the outlet end of the anode main line is connected to the inlet end of the anode three-way valve, the inlet end of the cathode main line is connected to the cathode discharge port of the electrolytic cell, and the outlet end of the cathode main line is connected to the inlet end of the cathode three-way valve; An anode reflux branch is connected downstream of the anode discharge port, and a cathode reflux branch is connected downstream of the cathode discharge port. Both the anode reflux branch and the cathode reflux branch are connected upstream of the reflux main line, and the anode reflux branch is connected in parallel with the cathode reflux branch. The outlet end of the reflux main line is connected to the reflux inlet of the electrolytic cell.

2. The water electrolysis system according to claim 1, characterized in that: The main reflux line is provided with a reflux circulation pump for causing the liquid in the main reflux line to flow to the electrolytic cell.

3. The water electrolysis system according to claim 2, characterized in that: A heat exchanger is arranged on the reflux main line.

4. The water electrolysis system according to claim 3, characterized in that: The heat exchanger is arranged upstream of the reflux circulation pump along the liquid flow direction in the reflux main line.

5. The water electrolysis system according to claim 1, characterized in that: It also includes an anode liquid level meter that cooperates with the inner cavity of the anode gas-liquid separation tank and a cathode liquid level meter that cooperates with the inner cavity of the cathode gas-liquid separation tank.

6. The water electrolysis system according to claim 5, characterized in that: The detection end of the anode liquid level gauge is adapted to the anode low-level cavity, and the detection end of the cathode liquid level gauge is adapted to the cathode low-level cavity.

7. The water electrolysis system according to claim 1, characterized in that: The anode partition plate is detachably mounted in the anode gas-liquid separation tank, and the cathode partition plate is detachably mounted in the cathode gas-liquid separation tank.

8. The water electrolysis system according to claim 1, characterized in that: The anode return branch is provided with an anode return valve for switching on and off, and the cathode return branch is provided with a cathode return valve for switching on and off.

9. A cold start method for a water electrolysis system, characterized in that: Includes steps: The electrolysis water system according to any one of claims 1 to 8 is used, and when the electrolysis water system is started from a cold state, the outlet end of the anode three-way valve connected to the anode low-position cavity is kept open, and the outlet end of the anode three-way valve connected to the anode high-position cavity is kept closed, and at the same time, the outlet end of the cathode three-way valve connected to the cathode low-position cavity is kept open, and the outlet end of the cathode three-way valve connected to the cathode high-position cavity is kept closed; The electrolytic cell is started. After the electrolytic cell electrolyzes the electrolyte inside, the electrolyte mixed with oxygen generated at the anode of the electrolytic cell is discharged through the anode discharge port of the electrolytic cell, and then transported to the anode low-position cavity through the anode main line and the anode three-way valve in sequence. These electrolytes are appropriately accumulated and allowed to stand in the anode low-position cavity to allow the oxygen mixed therein to escape. The escaped oxygen is discharged through the oxygen discharge pipe to meet the needs of the operation of the downstream oxygen-using equipment. The electrolyte in the anode low-position cavity has been heated to a higher temperature by the electrolysis treatment of the electrolytic cell, so it can be mixed with the original stored liquid in the anode low-position cavity, thereby rapidly increasing the liquid temperature in the anode low-position cavity; At the same time, the electrolyte mixed with hydrogen generated at the cathode of the electrolyzer is discharged through the cathode discharge port of the electrolyzer, and then transported to the cathode low-level cavity through the cathode main pipeline and the cathode three-way valve in sequence. These electrolytes are appropriately accumulated and left to stand in the cathode low-level cavity to allow the hydrogen mixed therein to escape. The escaped hydrogen is discharged through the hydrogen discharge pipe to meet the needs of the operation of downstream hydrogen-using equipment. The electrolyte in the cathode low-level cavity has been heated to a higher temperature by the electrolysis treatment of the electrolyzer, so it can be mixed with the original stored liquid in the cathode low-level cavity, thereby rapidly increasing the liquid temperature in the cathode low-level cavity; After the electrolysis water system has been running as a whole for a period of time, the liquid temperature in the anode low-level cavity and the cathode low-level cavity has risen to a temperature that meets the working condition requirements. At this time, the outlet end of the anode three-way valve connected to the anode high-level cavity and the outlet end of the cathode three-way valve connected to the cathode high-level cavity are opened respectively, so that the electrolyte discharged from the electrolytic cell and heated after electrolysis treatment is respectively passed into the anode high-level cavity and the cathode high-level cavity, until the liquid level of any one of the anode high-level cavity and the anode low-level cavity in the anode gas-liquid separation tank exceeds the upper edge of the anode partition plate, and the liquid level of any one of the cathode high-level cavity and the cathode low-level cavity in the cathode gas-liquid separation tank exceeds the upper edge of the cathode partition plate, thereby achieving liquid conduction between the anode low-level cavity and the anode high-level cavity and liquid conduction between the cathode low-level cavity and the cathode high-level cavity, and then completing the mixing and heating of the liquid in the entire anode gas-liquid separation tank cavity and the mixing and heating of the liquid in the entire cathode gas-liquid separation tank cavity, respectively, to match the current working condition requirements; After the electrolytic cell is started, the electrolyte in the anode gas-liquid separation tank is discharged through the anode drain port, and then transported to the inside of the electrolytic cell for recycling through the anode reflux branch, the reflux main line and the reflux inlet in sequence, while the electrolyte in the cathode gas-liquid separation tank is discharged through the cathode drain port, and then transported to the inside of the electrolytic cell for recycling through the cathode reflux branch, the reflux main line and the reflux inlet in sequence.

10. The cold start method of the water electrolysis system according to claim 9, characterized in that: When the liquid in the anode high-position cavity is connected to the anode low-position cavity and the liquid temperature in the anode gas-liquid separation tank has reached the working condition requirement, the outlet end of the anode three-way valve connected to the anode low-position cavity is closed, and the outlet end of the anode three-way valve connected to the anode high-position cavity is kept open; When the liquid in the cathode high-level cavity is connected to the cathode low-level cavity and the liquid temperature in the cathode gas-liquid separation tank has reached the operating requirements, close the outlet end of the cathode three-way valve connected to the cathode low-level cavity, and keep the outlet end of the cathode three-way valve connected to the cathode high-level cavity open.

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