Gas-liquid separator with purification function and electrolytic hydrogen production system

Abstract

The invention relates to a gas-liquid separator with a purification function and an electrolytic hydrogen production system. The gas-liquid separator comprises a pressure electrolytic bath, a circulating tank and three groups of gas-liquid separators, the pressure electrolytic cell electrolyzes water to decompose hydrogen and oxygen through an alkaline solution, the pressure valve controls the cathode liquid outlet to be opened after detecting that the air pressure in the pressure electrolytic cell reaches a high pressure value, and catholyte bubble water enters the circulation tank. The first-stage gas-liquid separator and the second-stage gas-liquid separator are used for receiving the catholyte containing bubbles at the first liquid outlet and the target gas containing more impurities at the third gas outlet, carrying out gas-liquid separation to obtain the target gas containing a small amount of impurities, and discharging the catholyte; target gas containing a small amount of impurities enters the third-stage gas-liquid separator, high pressure generated in the pressure electrolytic cell provides power for the target gas to pass through a separation membrane, the target gas is separated from the remaining impurities, the volume ratio of the target gas in gas exhausted from a first gas outlet of the third-stage gas-liquid separator is larger than 99.999%, and the gas exhausted from a second gas outlet of the third-stage gas-liquid separator is larger than 99.999%. And high-pressure hydrogen can be directly supplied.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen production equipment, and in particular to a gas-liquid separator with purification function and an electrolytic hydrogen production system. Background Art

[0002] With the rapid development of the hydrogen energy industry, the application scenarios requiring high-pressure hydrogen are increasing, and the demand for electrolyzers that can directly produce high-pressure hydrogen and the corresponding high-pressure gas-liquid separators is also increasing.

[0003] Existing water electrolysis hydrogen production systems usually include an electrolyzer and a multi-stage gas-liquid separator. In addition to the required hydrogen, the gas discharged from the electrolyzer also contains impurities such as oxygen and alkaline water. Even with a multi-stage gas-liquid separator, the purity of hydrogen can only reach 99%, which cannot meet the purification requirements. If the purity of hydrogen needs to reach 99.999%, it is necessary to add a compressor and a purifier at the rear end of the gas-liquid separator, which has high equipment cost, complex structure and high energy consumption.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] In view of the deficiencies in the prior art, the embodiments of the present invention disclose a gas-liquid separator with a purification function and an electrolytic hydrogen production system to solve the problems of high cost and high energy consumption in producing high-purity hydrogen by the electrolytic hydrogen production system.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A gas-liquid separator with a purification function, the gas-liquid separator comprising: a first tank body, having a first cavity inside, comprising: a first air inlet and a first air outlet, arranged at the upper end of the first tank body, the first air inlet introducing a target gas mixed with impurities into the first cavity, the molecular diameter of the target gas being smaller than the molecular diameter of the impurity; a second air outlet, arranged at the lower end of the first tank body; a separation mechanism, comprising: a container body, the lower end of which is fixed to the bottom of the first cavity, having a second cavity inside, the second cavity not being directly connected to the first cavity; a separation membrane, fixedly sleeved on the The outer side of the container body is provided with a nanopore on the surface, and the pore size of the nanopore is larger than the diameter of the target gas molecule and smaller than the diameter of the impurity molecule; a through hole is provided on the side of the container body, and the position corresponds to the nanopore; the gas outlet pipe is arranged in the first cavity, and the first end is connected to the second cavity, and the second end is connected to the first gas outlet; wherein the air pressure in the first cavity is at least 0.6MPa greater than the air pressure in the second cavity, so that the target gas passes through the nanopore and the through hole in turn into the second cavity, and the impurities sink and are discharged through the second gas outlet to achieve gas-gas separation.

[0008] Its further technical solution is that the container body includes: a support body, which is a hollow cylinder; a base, which has two parts and is respectively fixed to the upper end and the lower end of the outer side of the support body; a cover body, which has two parts and is respectively arranged at one end of the base away from the support body; wherein the base and the cover body located at the lower end of the support body are connected to the first tank body with screws, and the base located at the upper end of the support body is connected to the cover body with screws, the through hole is opened on the side of the support body, and the first end of the air outlet pipe is connected to the cover body located at the upper end of the support body.

[0009] A further technical solution is that the container body also includes: an air outlet channel, which is opened on the cover body located at the lower end of the support body, with a first end connected to the first cavity and a second end connected to the second air outlet, and not connected to the second cavity.

[0010] A further technical solution is that the air pressure in the first cavity is 0.6 to 0.8 MPa greater than the air pressure in the second cavity.

[0011] A further technical solution is that the separation membrane is made of a high molecular polymer nanofiber film or a silicon nanofiber film.

[0012] The present invention also discloses an electrolytic hydrogen production system, which includes: a pressure electrolyzer, including: a cathode liquid outlet, discharging cathode electrolyte bubble water; a pressure valve, arranged at the cathode liquid outlet, detecting whether the gas pressure in the pressure electrolyzer reaches a set value and controlling the opening and closing of the cathode liquid outlet; a circulation tank, including a second tank body, a side of the second tank body having a first inlet connected to the cathode liquid outlet, a third gas outlet at the upper end, and a first liquid outlet at the lower end of the side; a gas-liquid separator, receiving the cathode electrolyte containing bubbles at the first liquid outlet, receiving the target gas with more impurities at the third gas outlet and performing gas-liquid separation to obtain a target gas with less impurities and discharge the cathode electrolyte; a three-stage gas-liquid separator, as mentioned above, the first gas inlet receiving the target gas with less impurities after gas-liquid separation by the gas-liquid separator.

[0013] Its further technical solution is that the gas-liquid separator includes a primary gas-liquid separator and a secondary gas-liquid separator; the primary gas-liquid separator includes: a third tank body, having a fourth air inlet and a fourth air outlet at the upper end, a second liquid outlet at the lower end, and a second liquid inlet at the upper and lower ends of the side, the fourth air inlet is connected to the third air outlet, and the second liquid inlet is connected to the first liquid outlet; the secondary gas-liquid separator includes: a fourth tank body, having a fifth air inlet and a fifth air outlet at the upper end, a third liquid outlet at the lower end, the fifth air inlet is connected to the fourth air outlet, and the fifth air outlet is connected to the first air inlet.

[0014] Its further technical solution is that the second liquid inlet is connected to the first liquid outlet by a U-shaped tube; the secondary gas-liquid separator separates the gaseous liquid in the impurities by condensation; the pressure electrolyzer also includes a liquid return port, the liquid return port is connected to a liquid return pump, and the liquid return pump is connected to the second liquid outlet and the third liquid outlet.

[0015] A further technical solution is that the set value of the gas pressure in the pressure electrolytic cell is greater than 22MPa, and the temperature of the cathode electrolyte and gas is 60-80°C.

[0016] A further technical solution is that the volume ratio of the target gas in the gas discharged from the first gas outlet is greater than 99.999%.

[0017] The beneficial effects of the embodiments of the present invention are as follows:

[0018] (I) The gas-liquid separator with purification function of the present invention comprises a first tank body and a separation mechanism. When the gas-liquid separator is performing separation and purification, under the premise that there is a certain pressure difference between the first cavity and the second cavity, the target gas with a smaller molecular diameter passes through the nanopores of the separation membrane under the action of pressure and enters the second cavity, while the impurities with a larger molecular diameter sink in the first cavity and are discharged through the second gas outlet due to their large mass and inability to pass through the nanopores. The target gas is output to the application scene through the gas outlet pipe and the first gas outlet, thereby realizing the separation and purification of the target gas and impurities. The structure is simple, the use is convenient, the separation purity is high, and it is suitable for the case where the molecular diameter of the target gas is smaller than the molecular diameter of the impurity.

[0019] In addition, the separation membrane is sleeved on the outside of the container body. When separation and purification is performed, the separation membrane presses the container body inward. The container body has high compressive strength and good support effect for the separation membrane, and is suitable for high-pressure hydrogenation environment.

[0020] (ii) Further, the electrolytic hydrogen production system of the present invention includes a pressure electrolyzer, a circulation tank and three groups of gas-liquid separators. The pressure electrolyzer produces hydrogen and oxygen by electrolyzing water with an alkaline solution. After the pressure valve detects that the air pressure in the pressure electrolyzer reaches a high pressure value, it controls the cathode liquid outlet to open, and the cathode electrolyte bubble water enters the circulation tank. The first-level gas-liquid separator and the second-level gas-liquid separator receive the cathode electrolyte containing bubbles at the first liquid outlet and receive the target gas with more impurities at the third gas outlet and perform gas-liquid separation to obtain a target gas containing a small amount of impurities and discharge the cathode electrolyte. The target gas containing a small amount of impurities enters the third-level gas-liquid separator. The high pressure generated in the pressure electrolyzer provides power for the target gas to pass through the separation membrane, thereby separating the target gas from the remaining impurities. The volume ratio of the target gas in the gas discharged from the first gas outlet of the third-level gas-liquid separator is greater than 99.999%, which can directly supply high-pressure hydrogen usage scenarios.

[0021] (iii) Furthermore, the high pressure required for the separation membrane purification of the three-stage gas-liquid separator is directly generated by the pressure electrolyzer during the electrolysis process, without the need for additional compressors and purifiers. The equipment cost is low, the energy consumption is low, the number of equipment used is small, the number of pipelines is small, and it is suitable for high-pressure hydrogen production.

[0022] (iv) Furthermore, the second liquid inlet is connected to the first liquid outlet via a U-shaped tube, the U-shaped opening of the U-shaped tube faces upward, and the electrolyte is retained in the U-shaped tube, which can avoid gas backflow and ensure gas separation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the gas-liquid separator with purification function of the present invention.

[0024] Figure 2 It is a structural schematic diagram of the electrolytic hydrogen production system of the present invention.

[0025] In the figure:

[0026] 1. Three-stage gas-liquid separator; 11. First tank body; 111. First cavity; 112. First air inlet; 113. First air outlet; 114. Second air outlet; 115. Flange cover; 12. Separation mechanism; 121. Container body; 1211. Support body; 1212. Base; 1213. Cover body; 1214. Second cavity; 122. Separation membrane; 123. Air outlet channel; 124. Air outlet pipe; 2. Pressure electrolyzer; 21. Pressure valve ; 22. cathode liquid outlet; 3. circulation tank; 31. second tank body; 32. first inlet; 33. third gas outlet; 34. first liquid outlet; 35. U-shaped tube; 4. primary gas-liquid separator; 41. third tank body; 42. fourth gas inlet; 43. fourth gas outlet; 44. second liquid inlet; 45. second liquid outlet; 5. secondary gas-liquid separator; 51. fourth tank body; 52. fifth gas inlet; 53. fifth gas outlet; 54. third liquid outlet. DETAILED DESCRIPTION

[0027] The specific implementation of the present invention will be described below in conjunction with the accompanying drawings.

[0028] In order to make the purpose, technical scheme and advantages of the present invention clearer, the device proposed by the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings adopt a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, please refer to the accompanying drawings. It should be noted that the structure, proportion, size, etc. illustrated by the accompanying drawings of this specification are only used to match the content disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no technical substantive significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effect that the present invention can produce and the purpose that can be achieved, should still fall within the scope of the technical content disclosed by the present invention.

[0029] First embodiment:

[0030] This embodiment discloses a gas-liquid separator with a purification function.

[0031] like Figure 1 As shown, the gas-liquid separator with purification function includes a first tank body 11 and a separation mechanism 12 .

[0032] The first tank body 11 has a first cavity 111 inside, including a first air inlet 112, a first air outlet 113 and a second air outlet 114. The first air inlet 112 and the first air outlet 113 are arranged at the upper end of the first tank body 11, and the first air inlet 112 introduces a target gas mixed with impurities into the first cavity 111, and the molecular diameter of the target gas is smaller than the molecular diameter of the impurity. The second air outlet 114 is arranged at the lower end of the first tank body 11. Exemplarily, the upper and lower ends of the first tank body 11 are bolted to a flange cover 115, the first air inlet 112 and the first air outlet 113 are opened on the flange cover 115 at the upper end, and the second air outlet 114 is opened on the flange cover 115 at the lower end, so as to facilitate the installation and disassembly of the internal separation mechanism 12. The first air inlet 112, the first air outlet 113 and the second air outlet 114 are all equipped with quick-connect plugs, which are convenient for plugging and unplugging with external pipelines.

[0033] The separation mechanism 12 includes a container body 121, a separation membrane 122, a through hole and an air outlet pipe 124. The lower end of the container body 121 is fixed to the bottom of the first cavity 111, and has a second cavity 1214 inside, which is not directly connected to the first cavity 111. The separation membrane 122 is sleeved on the outside of the container body 121, and has nanopores on the surface. The pore size of the nanopore is larger than the diameter of the target gas molecule and smaller than the diameter of the impurity molecule. The through hole is opened on the side of the container body 121, and the position corresponds to the nanopore.

[0034] Exemplarily, the container body 121 includes a support body 1211, a base 1212 and a cover body 1213. The support body 1211 is a hollow cylinder. There are two bases 1212, which are respectively fixed to the upper end and the lower end of the outer side of the support body 1211. There are two covers 1213, which are respectively arranged at one end of the base 1212 away from the support body 1211. Among them, the base 1212 and the cover body 1213 located at the lower end of the support body 1211 are screwed to the flange cover 115, the base 1212 located at the upper end of the support body 1211 is screwed to the cover body 1213, a through hole is opened on the side of the support body 1211, the separation membrane 122 is sleeved on the outer side of the support body 1211, and the first end of the air outlet pipe 124 is connected to the cover body 1213 located at the upper end of the support body 1211. Specifically, the support body 1211 can be a porous mesh, and a disc support with a through hole is horizontally arranged inside. The separation membrane 122 is made of a polymer nanofiber membrane or a silicon nanofiber membrane.

[0035] Further, the air outlet pipe 124 is disposed in the first cavity 111, with a first end connected to the second cavity 1214, and a second end connected to the first air outlet 113. Exemplarily, the air outlet pipe 124 is a hose.

[0036] The air pressure in the first cavity 111 is at least 0.6 MPa greater than the air pressure in the second cavity 1214, so that the target gas passes through the nanopores and the through holes in turn into the second cavity 1214, and the impurities sink and are discharged through the second gas outlet 114 to achieve gas-gas separation. Preferably, the air pressure in the first cavity 111 is 0.6 to 0.8 MPa greater than the air pressure in the second cavity 1214. The greater the input pressure in the first cavity 111, the greater the delivery pressure in the second cavity 1214, and the faster the delivery speed, but it cannot exceed the upper limit of the pressure that the separation membrane 122 and the support body 1211 can withstand.

[0037] Furthermore, the container body 121 also includes an air outlet channel 123, which is opened on the cover body 1213 located at the lower end of the support body 1211, with a first end connected to the first cavity 111 and a second end connected to the second air outlet 114, and is not connected to the second cavity 1214. The air outlet channel 123 discharges oxygen that sinks in the first cavity 111 and is opened on the cover body 1213, which is convenient for maintenance and replacement when the air outlet channel 123 is blocked.

[0038] In this embodiment, when the gas-liquid separator with purification function is performing separation and purification, under the premise that there is a certain pressure difference between the first cavity 111 and the second cavity 1214, the target gas with a smaller molecular diameter passes through the nanopores of the separation membrane 122 under the action of pressure and enters the second cavity 1214, while the impurities with a larger molecular diameter sink in the first cavity 111 and are discharged through the second gas outlet 114 due to their large mass and inability to pass through the nanopores. The target gas is output to the application scene through the gas outlet pipe 124 and the first gas outlet 113, thereby realizing the separation and purification of the target gas and impurities. The structure is simple, easy to use, and has high separation purity. It is suitable for situations where the molecular diameter of the target gas is smaller than the molecular diameter of the impurity.

[0039] In addition, the separation membrane 122 is fixedly sleeved on the outside of the container body 121. When separation and purification is performed, the separation membrane 122 presses the container body 121 inwardly. The container body 121 has high compressive strength and good support effect for the separation membrane 122, and is suitable for high-pressure hydrogenation environment.

[0040] Second embodiment:

[0041] This embodiment discloses a hydrogen production system by electrolysis.

[0042] like Figure 2 As shown, the electrolytic hydrogen production system includes a pressure electrolyzer 2, a circulation tank 3, a gas-liquid separator and a three-stage gas-liquid separator 1.

[0043] The pressure electrolyzer 2 includes a cathode liquid outlet 22 and a pressure valve 21. The cathode liquid outlet 22 discharges the cathode electrolyte and the target gas mixed with impurities. The pressure valve 21 is arranged at the cathode liquid outlet 22 to detect whether the air pressure in the pressure electrolyzer 2 reaches the set value and control the opening and closing of the cathode liquid outlet 22. Specifically, the set value of the air pressure in the pressure electrolyzer 2 is greater than 22MPa, the temperature of the cathode electrolyte and the gas is 60-80°C, and the alkaline solution is electrolyzed to generate hydrogen and oxygen and form high pressure.

[0044] The circulation tank 3 comprises a second tank body 31, which has a first inlet 32 ​​on the side thereof connected to the cathode liquid outlet 22, a third gas outlet 33 on the upper end thereof, and a first liquid outlet 34 on the lower end thereof. The first inlet 32 ​​receives cathode electrolyte bubble water from the cathode liquid outlet 22.

[0045] The gas-liquid separator receives the cathode electrolyte containing bubbles from the first liquid outlet 34 , receives the target gas with more impurities from the third gas outlet 33 and performs gas-liquid separation to obtain the target gas containing a small amount of impurities and discharge the cathode electrolyte.

[0046] Exemplarily, the gas-liquid separator includes a primary gas-liquid separator 4 and a secondary gas-liquid separator 5. The primary gas-liquid separator 4 includes a third tank body 41, the upper end of the third tank body 41 has a fourth air inlet 42 and a fourth air outlet 43, the upper and lower ends of the side have a second liquid inlet 44, the lower end has a second liquid outlet 45, the fourth air inlet 42 is connected to the third air outlet 33, and the second liquid inlet 44 is connected to the first liquid outlet 34. The secondary gas-liquid separator 5 includes a fourth tank body 51, the upper end of the fourth tank body 51 has a fifth air inlet 52 and a fifth air outlet 53, the lower end has a third liquid outlet 54, the fifth air inlet 52 is connected to the fourth air outlet 43, and the fifth air outlet 53 is connected to the first air inlet 112. Specifically, the purity of hydrogen after gas-liquid separation by the primary gas-liquid separator 4 is about 95%. The secondary gas-liquid separator 5 separates the gaseous liquid from the impurities by condensation. After the gas-liquid separation in the secondary gas-liquid separator 5, the purity of hydrogen is about 99%.

[0047] The air inlet and the air outlet, and the liquid inlet and the liquid outlet are connected by a hose. Preferably, the second liquid inlet 44 and the first liquid outlet 34 are connected by a U-shaped tube 35, the U-shaped opening of the U-shaped tube 35 faces upward, and the electrolyte is retained in the U-shaped tube 35, which can avoid gas backflow and ensure gas separation efficiency.

[0048] The three-stage gas-liquid separator 1 is as described in the first embodiment, and the first gas inlet 112 receives the target gas with less impurities after gas-liquid separation by the gas-liquid separator. The gas pressure generated by the gas in the pressure electrolyzer 2 provides the three-stage gas-liquid separator 1 with a pressure difference for separation and purification.

[0049] The pressure electrolyzer 2 further includes a liquid return port, which is connected to a liquid return pump, and the liquid return pump is connected to the second liquid outlet 45 and the third liquid outlet 54. The pressure electrolyzer 2 further includes an anode liquid outlet, which discharges the anode electrolyte and gas without the target gas, discharges impurities after gas-liquid separation, and recovers the electrolyte through the liquid return pump.

[0050] In this embodiment, the pressure electrolyzer 2 generates hydrogen and oxygen by electrolyzing water with an alkaline solution. After the pressure valve 21 detects that the air pressure in the pressure electrolyzer 2 reaches a high pressure value, it controls the cathode liquid outlet 22 to open, and the cathode electrolyte bubble water enters the circulation tank 3. The gas-liquid separator receives the cathode electrolyte containing bubbles at the first liquid outlet 34 and receives the target gas with more impurities at the third gas outlet 33 and performs gas-liquid separation to obtain the target gas containing a small amount of impurities and discharge the cathode electrolyte. The target gas containing a small amount of impurities enters the three-stage gas-liquid separator 1. The high pressure generated in the pressure electrolyzer 2 provides power for the target gas to pass through the separation membrane 122, so as to separate the target gas from the remaining impurities. The volume ratio of the target gas in the gas discharged from the first gas outlet 113 of the three-stage gas-liquid separator 1 is greater than 99.999%, which can directly supply the high-pressure hydrogen use scenario, and the high pressure is directly generated by the pressure electrolyzer 2 during the electrolysis process, without the need to add an additional compressor and a purifier. The equipment cost is low, the energy consumption is low, the equipment used is small, the pipeline is small, and it is suitable for high-pressure hydrogen production.

[0051] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0052] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A gas-liquid separator with purification function, characterized in that: The gas-liquid separator comprises: The first tank body has a first cavity therein and includes: A first air inlet and a first air outlet are arranged at the upper end of the first tank body, the first air inlet introduces a target gas mixed with impurities into the first cavity, and the molecular diameter of the target gas is smaller than that of the impurity molecules; A second air outlet is provided at the lower end of the first tank body; Separation agencies, including: A container body, the lower end of which is fixed to the bottom of the first cavity, and has a second cavity inside, and the second cavity is not directly connected to the first cavity; A separation membrane is fixedly sleeved on the outside of the container body, and has nanopores on its surface, wherein the pore size of the nanopores is larger than the diameter of target gas molecules and smaller than the diameter of impurity molecules; A through hole is provided on the side of the container body and its position corresponds to the nanopore; an air outlet pipe, disposed in the first cavity, with a first end connected to the second cavity and a second end connected to the first air outlet; The air pressure in the first cavity is at least 0.6 MPa greater than the air pressure in the second cavity, so that the target gas passes through the nanopores and the through holes in sequence into the second cavity, and the impurities sink and are discharged through the second gas outlet to achieve gas-gas separation.

2. The gas-liquid separator with purification function according to claim 1, characterized in that: The container body comprises: The support body is a hollow cylinder; A base having two parts, which are respectively fixed to the upper end and the lower end of the outer side of the support body; The cover body has two parts, and is respectively arranged at one end of the base away from the support body; Among them, the base and cover body located at the lower end of the support body are connected to the first tank body by screws, the base and cover body located at the upper end of the support body are connected to the screws, the through hole is opened on the side of the support body, and the first end of the air outlet pipe is connected to the cover body located at the upper end of the support body.

3. The gas-liquid separator with purification function according to claim 2, characterized in that: The container body also includes: The air outlet channel is opened on the cover body at the lower end of the support body, the first end of which is connected to the first cavity, the second end of which is connected to the second air outlet and is not connected to the second cavity.

4. The gas-liquid separator with purification function according to claim 1, characterized in that: The air pressure in the first cavity is 0.6-0.8 MPa greater than the air pressure in the second cavity.

5. The gas-liquid separator with purification function according to claim 1, characterized in that: The separation membrane is a high molecular polymer nanofiber film or a silicon nanofiber film.

6. An electrolytic hydrogen production system, characterized in that: The electrolysis hydrogen production system comprises: Pressure electrolyzer, comprising: Cathode liquid outlet, discharging cathode electrolyte bubble water; A pressure valve, disposed at the cathode liquid outlet, detects whether the gas pressure in the pressure electrolyzer reaches a set value and controls the opening and closing of the cathode liquid outlet; A circulation tank, comprising a second tank body, wherein the second tank body has a first inlet on a side thereof connected to the cathode liquid outlet, a third gas outlet on an upper end thereof, and a first liquid outlet on a lower end thereof; A gas-liquid separator receives the cathode electrolyte containing bubbles from the first liquid outlet, receives the target gas with more impurities from the third gas outlet and performs gas-liquid separation to obtain the target gas containing a small amount of impurities and discharge the cathode electrolyte; The three-stage gas-liquid separator, as described in any one of claims 1 to 5, wherein the first gas inlet receives the target gas with less impurities after the gas-liquid separator performs gas-liquid separation.

7. The electrolysis hydrogen production system according to claim 6, characterized in that: The gas-liquid separator includes a primary gas-liquid separator and a secondary gas-liquid separator; the primary gas-liquid separator includes: A third tank body, having a fourth air inlet and a fourth air outlet at the upper end, a second liquid outlet at the lower end, and second liquid inlets at the upper and lower ends of the side, the fourth air inlet is connected to the third air outlet, and the second liquid inlet is connected to the first liquid outlet; The secondary gas-liquid separator comprises: The fourth tank body has a fifth air inlet and a fifth air outlet at the upper end and a third liquid outlet at the lower end. The fifth air inlet is connected to the fourth air outlet, and the fifth air outlet is connected to the first air inlet.

8. The electrolysis hydrogen production system according to claim 7, characterized in that: The second liquid inlet is connected to the first liquid outlet via a U-shaped tube; the secondary gas-liquid separator separates gaseous liquid from impurities by condensation; the pressure electrolyzer also includes a liquid return port, the liquid return port is connected to a liquid return pump, and the liquid return pump is connected to the second liquid outlet and the third liquid outlet.

9. The electrolysis hydrogen production system according to claim 6, characterized in that: The set value of the gas pressure in the pressure electrolyzer is greater than 22MPa, and the temperature of the cathode electrolyte and gas is 60-80°C.

10. The electrolysis hydrogen production system according to claim 6, characterized in that: The volume ratio of the target gas in the gas discharged from the first gas outlet is greater than 99.999%.

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