System and method for producing high-pressure hydrogen by coupling proton exchange membrane water electrolyser with electrochemical compressor

Abstract

The invention relates to the technical field of electrolytic hydrogen production, and discloses a system and a method for producing high-pressure hydrogen by coupling a proton exchange membrane water electrolyzer with an electrochemical compressor, the system comprises a hydrogen production PEM electrolyzer, an electrochemical compressor and a gas-liquid separator; wherein the hydrogen production PEM electrolytic bath is provided with an oxygen production outlet and a hydrogen production outlet; the gas-liquid separator comprises an oxygen production side gas-liquid separator and a hydrogen production side gas-liquid separator; the oxygen production outlet is connected with an inlet of the oxygen production side gas-liquid separator, the hydrogen production outlet is connected with an inlet of the hydrogen production side gas-liquid separator, and the gas-liquid separator is connected with the electrochemical compressor. According to the system, the electrolytic bath and the electrochemical compressor are connected in series, so that the energy consumption in the high-pressure hydrogen production process can be reduced, the system efficiency is improved, excessive hydrogen content in oxygen caused by hydrogen reverse osmosis is prevented, and the system safety is enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrolytic hydrogen production, and in particular relates to a proton exchange membrane water electrolyzer coupled with an electrochemical compression mechanism high-pressure hydrogen system and method. Background Art

[0002] Among the key technical links in the industrial application of hydrogen energy, high-pressure hydrogen (10-100MPa) storage and transportation technology has attracted much attention due to its advantages in significantly improving hydrogen storage mass density and transportation economy. Taking the field of fuel cell vehicles as an example, the use of a 70MPa high-pressure hydrogen storage system can extend the vehicle's range to over 600 kilometers. This technical indicator has fully met the needs of commercial operations. However, the large-scale production and compression of high-pressure hydrogen at this stage still face multiple technical challenges: in the hydrogen production link, traditional fossil fuel reforming hydrogen production has problems such as high carbon emissions and insufficient hydrogen purity. Although alkaline water electrolysis can achieve low-carbon production, its current density limitation leads to low hydrogen production efficiency and is difficult to directly couple with fluctuating renewable energy. In the compression link, although traditional mechanical compression technology is widely used in the preparation of high-pressure hydrogen, it has problems such as low energy efficiency, complex multi-stage compression equipment, lubricant pollution, and high noise.

[0003] In this context, the proton exchange membrane (PEM) water electrolysis technology has a high current density (>2A / cm 2 ), fast start-stop characteristics and compact structure, it is considered to be an ideal hydrogen production path coupled with renewable energy. Thanks to the high mechanical strength of the proton exchange membrane, the PEM electrolyzer can directly produce high-pressure hydrogen. However, in actual operation, the PEM electrolyzer faces a key technical challenge, that is, under high hydrogen pressure conditions, the cathode hydrogen reverse osmosis through the membrane to the anode causing hydrogen and oxygen mixing. If the hydrogen content in the oxygen is within the explosion limit range of hydrogen in pure oxygen (4%-94%), it will pose a serious threat to the safety of the system operation. Summary of the Invention

[0004] To overcome the existing problem of high hydrogen pressure operating conditions, where reverse osmosis of cathode hydrogen through the membrane to the anode causes hydrogen and oxygen mixing, leading to safety concerns, the present invention proposes a high-pressure hydrogen system and method coupled with a proton exchange membrane water electrolyzer and an electrochemical compression mechanism. By connecting the hydrogen-producing PEM electrolyzer and the electrochemical compressor in series, the energy consumption of the high-pressure hydrogen production process can be reduced, thereby improving system efficiency. Furthermore, the system can prevent excessive hydrogen content in oxygen caused by hydrogen reverse osmosis, thereby enhancing system safety.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A proton exchange membrane water electrolyzer coupled with an electrochemical compression mechanism high-pressure hydrogen system, comprising a hydrogen production PEM electrolyzer, an electrochemical compressor, and a gas-liquid separator;

[0007] Among them, the hydrogen production PEM electrolyzer is provided with an oxygen production outlet and a hydrogen production outlet;

[0008] The gas-liquid separator includes an oxygen-producing side gas-liquid separator and a hydrogen-producing side gas-liquid separator; the oxygen-producing outlet is connected to the oxygen-producing side gas-liquid separator inlet, the hydrogen-producing outlet is connected to the hydrogen-producing side gas-liquid separator inlet, and the gas-liquid separator is connected to the electrochemical compressor.

[0009] Furthermore, the electrochemical compressor includes a cathode end plate, a cathode plate, a first cathode titanium felt, a first membrane electrode, a first anode titanium felt, a first gasket, a bipolar plate, a second cathode titanium felt, a second membrane electrode, a second gasket, a second anode titanium felt, an anode plate and an anode end plate, which are arranged in sequence;

[0010] Among them, fluid channels are opened inside the cathode plate, anode plate and bipolar plate, and the fluid channels are divided into two areas by the first membrane electrode, the second membrane electrode and the first gasket and the second gasket. The area in contact with the anode catalyst layer of the first membrane electrode and the second membrane electrode is the low-pressure hydrogen side, and the area in contact with the cathode catalyst layer of the first membrane electrode and the second membrane electrode is the high-pressure hydrogen side.

[0011] Furthermore, sealing rings are provided on both sides of the first membrane electrode and the second membrane electrode.

[0012] Furthermore, a first anode sealing ring is provided on one side of the first membrane electrode, and a first metal pad is provided on the other side. The first anode sealing ring is symmetrically arranged on both sides of the first membrane electrode, and the first metal pad and the bipolar plate jointly press the first anode sealing ring;

[0013] A first cathode sealing ring is provided on one side of the first membrane electrode, and a second metal pad is provided on the other side. The first cathode sealing ring and the second metal pad are symmetrically arranged on both sides of the first membrane electrode, and the cathode plate and the second metal pad jointly press the first cathode sealing ring.

[0014] Furthermore, a second anode sealing ring is provided on one side of the second membrane electrode, and a third metal pad is provided on the other side. The third metal pad and the second anode sealing ring are symmetrically arranged on both sides of the second membrane electrode, and the third metal pad and the anode plate jointly press the second anode sealing ring;

[0015] A second cathode sealing ring is provided on one side of the second membrane electrode, and a fourth metal pad is provided on the other side. The second cathode sealing ring and the fourth metal pad are symmetrically arranged on both sides of the second membrane electrode, and the bipolar plate and the fourth metal pad jointly press the second cathode sealing ring.

[0016] Furthermore, the system also includes a first DC power supply and a second DC power supply, the positive electrode and negative electrode of the first DC power supply are respectively connected to the electrode plates corresponding to the oxygen production side and the hydrogen production side of the hydrogen production PEM electrolyzer; the positive electrode and negative electrode of the second DC power supply are respectively connected to the anode plate and cathode plate of the electrochemical compressor.

[0017] Furthermore, the hydrogen production PEM electrolyzer is connected to a water tank, and the water tank outlet is connected to the water inlet of the hydrogen production PEM electrolyzer via a dosing pump, a first stop valve, a second stop valve, and a circulation pump;

[0018] The system also includes a gas drying and purification tube, which includes a low-pressure hydrogen side gas drying and purification tube and a high-pressure hydrogen side gas drying and purification tube. The low-pressure hydrogen side gas drying and purification tube is arranged at the low-pressure hydrogen outlet of the electrochemical compressor, and the high-pressure hydrogen side gas drying and purification tube is arranged at the high-pressure hydrogen outlet of the electrochemical compressor.

[0019] Furthermore, a humidity controller is provided on the pipeline between the gas outlet of the gas-liquid separator on the hydrogen production side and the electrochemical compressor.

[0020] A high-pressure hydrogen method using a proton exchange membrane water electrolyzer coupled with an electrochemical compression mechanism comprises the following steps:

[0021] Water is oxidized on the anode side of the hydrogen production PEM electrolyzer to generate oxygen and hydrogen ions. The hydrogen ions are transferred to the cathode side through the membrane electrode under the action of the electric field and are reduced to hydrogen.

[0022] Hydrogen flows out from the hydrogen production outlet of the electrolyzer, passes through the gas-liquid separator on the hydrogen production side, and then enters the electrochemical compressor;

[0023] Hydrogen is oxidized at the anode of the electrochemical compressor to generate hydrogen ions. The hydrogen ions are transferred to the cathode side through the membrane electrode under the action of the electric field and are reduced to hydrogen. The unreacted hydrogen is discharged from the low-pressure hydrogen outlet of the electrochemical compressor; the generated high-pressure hydrogen is discharged from the high-pressure hydrogen outlet of the electrochemical compressor.

[0024] Furthermore, the hydrogen in the hydrogen-producing PEM electrolyzer enters the gas-liquid separator for gas-liquid separation, and the separated hydrogen enters the humidity controller to monitor the water vapor content in the hydrogen in real time, and adjust the gas phase water content in the hydrogen within the preset threshold range through the humidity controller.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention constructs an electrolysis-compression collaborative system through system integration design and process optimization: first, a PEM electrolyzer is used to prepare hydrogen at a basic pressure, and then a secondary hydrogen boost is achieved through an electrochemical compressor. Under the premise of ensuring the mechanical integrity of the proton exchange membrane, this technology not only realizes normal pressure / low pressure operation of the electrolysis link to reduce the hydrogen reverse osmosis rate, but also achieves the target pressure output through the efficient boosting characteristics of electrochemical compression. Compared with the traditional high-pressure electrolysis direct hydrogen production process, this system can greatly reduce the compression energy consumption, and at the same time strictly control the hydrogen concentration in the oxygen on the anode side to below the lower explosion limit (4%), eliminating the risk of hydrogen-oxygen mixed explosion from the mechanism level, providing an innovative solution for the inherent safety of the hydrogen energy system, and providing a new idea for the construction of a low-cost and high-safety direct high-pressure hydrogen electrolysis water system. Compared to traditional mechanical compression technology, the present invention uses an electrochemical compressor (EHC) as the core unit for hydrogen boosting, achieving a 20-40% increase in energy conversion efficiency compared to mechanical compression. This not only eliminates the system complexity associated with multi-stage compression equipment, but also avoids the energy loss and equipment maintenance issues caused by mechanical moving parts, significantly improving operational reliability and energy efficiency. It is particularly noteworthy that although the purity of hydrogen produced by PEM electrolysis can reach over 99.9%, trace amounts of oxygen permeating into the hydrogen side can still result in the presence of oxygen in the hydrogen. The selective migration of protons during the electrochemical hydrogen compression process can further purify the hydrogen, a feature that traditional mechanical compressors simply lack.

[0027] Furthermore, by rationally designing the gas-liquid separator on the hydrogen production side, it is possible to separate the liquid components in the gaseous products and control the water vapor partial pressure in the hydrogen carrier flow; the water content in the gas phase entering the electrochemical compressor is controlled by a humidity controller and regulated within a preset threshold range, thereby optimizing the mass transfer kinetics of the electrochemical proton migration interface in the electrochemical compressor and improving the efficiency of high-pressure hydrogen production.

[0028] Furthermore, a metering pump replenishes deionized water in the oxygen-producing circuit at regular intervals and in fixed quantities based on the rate of electrolyzed water consumption. A circulating pump drives water through the oxygen-producing circuit, connecting the liquid outlet of the oxygen-producing gas-liquid separator to the water inlet of the hydrogen-producing PEM electrolyzer. This allows for water recycling during the electrolysis process, reducing the demand for ultrapure water and lowering operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of a proton exchange membrane water electrolyzer coupled with an electrochemical compression mechanism high-pressure hydrogen system of the present invention.

[0030] Figure 2 This is a schematic diagram of the structure of the electrochemical compressor in the present invention.

[0031] Figure 3 Schematic diagram of the sealing structure of the electrochemical compressor in the present invention.

[0032] In the figure, 1. water tank, 2. dosing pump, 3. first stop valve, 4. second stop valve, 5. circulation pump, 6. first DC power supply, 7. hydrogen production PEM electrolyzer, 8. third stop valve, 9. oxygen production side gas-liquid separator, 10. oxygen storage tank, 11. fourth stop valve, 12. hydrogen production side gas-liquid separator, 13. fifth stop valve, 14. second DC power supply, 15. electrochemical compressor, 16. low-pressure hydrogen side gas drying and purification pipe, 17. first pressure-stabilizing valve, 18. low-pressure hydrogen storage tank, 19. second pressure-stabilizing valve, 20. high-pressure hydrogen side gas drying and purification pipe, 21. high-pressure hydrogen storage tank, 22. third pressure-stabilizing valve, 23. humidity controller.

[0033] Figure 2 In the figure, 24. cathode end plate, 25. cathode plate, 26. first cathode titanium felt, 27. first membrane electrode, 28. first anode titanium felt, 29. first gasket, 30. bipolar plate, 31. second cathode titanium felt, 32. second membrane electrode, 33. second gasket, 34. second anode titanium felt, 35. anode plate, 36. anode end plate.

[0034] Figure 3 Among them, 37. first cathode sealing ring, 38. first anode sealing ring, 39. second cathode sealing ring, 40. second anode sealing ring, 41. first metal pad, 42. second metal pad, 43. third metal pad, 44. fourth metal pad. DETAILED DESCRIPTION

[0035] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present invention. However, the present invention may be implemented in a variety of different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0036] In addition, when an element in the present invention is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0037] Electrochemical Hydrogen Compressor (EHC) technology uses an applied electric potential to drive the dissociation of hydrogen molecules into protons, which then travel across a proton exchange membrane and recombine at the cathode side to form high-purity, high-pressure hydrogen. This technology theoretically achieves isothermal compression, increasing efficiency by 20-40% compared to mechanical compression. Furthermore, electrochemical compressors have no moving parts, significantly improving their quietness and safety compared to mechanical compressors, demonstrating significant technical advantages and application prospects.

[0038] like Figure 1 As shown, the present invention provides a proton exchange membrane water electrolyzer coupled with an electrochemical compression mechanism high-pressure hydrogen system, comprising: a water tank 1, a hydrogen-producing PEM electrolyzer 7, an electrochemical compressor 15 and a gas-liquid separator.

[0039] The hydrogen-producing PEM electrolyzer 7 generates hydrogen and oxygen by electrolyzing water. In this system, the hydrogen-producing PEM electrolyzer 7 has an oxygen-producing outlet and a hydrogen-producing outlet, corresponding to the oxygen-producing side and the hydrogen-producing side, respectively. When water is electrolyzed, hydrogen is produced on the hydrogen-producing side and oxygen is produced on the oxygen-producing side.

[0040] The electrochemical compressor 15 is provided with a high-pressure hydrogen outlet and a low-pressure hydrogen outlet;

[0041] The gas-liquid separator includes an oxygen-producing side gas-liquid separator 9 and a hydrogen-producing side gas-liquid separator 12; the oxygen-producing outlet is connected to the inlet of the oxygen-producing side gas-liquid separator 9, and the hydrogen-producing outlet is connected to the inlet of the hydrogen-producing side gas-liquid separator 12; the outlet of the oxygen-producing side gas-liquid separator 9 is connected to the oxygen storage tank 10, and the outlet of the hydrogen-producing side gas-liquid separator 12 is connected to the low-pressure hydrogen inlet of the electrochemical compressor 15.

[0042] Specifically, the outlet of the water tank 1 is connected to the water inlet of the hydrogen-producing PEM electrolyzer 7 via a dosing pump 2, a first shut-off valve 3, a second shut-off valve 4, and a circulation pump 5. The oxygen-producing outlet of the hydrogen-producing PEM electrolyzer 7 is connected to an oxygen-producing gas-liquid separator 9 via a third shut-off valve 8. The liquid outlet of the oxygen-producing gas-liquid separator 9 is connected to the second shut-off valve 4. The gas outlet of the oxygen-producing gas-liquid separator 9 is connected to an oxygen storage tank 10. The hydrogen production outlet of the hydrogen-producing PEM electrolyzer 7 is connected to the hydrogen production-side gas-liquid separator 12 via a fourth shut-off valve 11. The liquid outlet of the hydrogen production-side gas-liquid separator 12 is connected to a fifth shut-off valve 13. The gas outlet of the hydrogen production-side gas-liquid separator 12 is connected to an electrochemical compressor 15. A humidity controller 23 is provided on the pipeline between the gas outlet of the hydrogen production-side gas-liquid separator 12 and the electrochemical compressor 15. The high-pressure hydrogen outlet of the electrochemical compressor 15 is connected to a high-pressure hydrogen storage tank 21 via a second pressure-stabilizing valve 19 and a high-pressure hydrogen-side gas drying and purification pipe 20. The high-pressure hydrogen storage tank 21 is provided with a third pressure-stabilizing valve 22. The low-pressure hydrogen outlet of the electrochemical compressor 15 is connected to a low-pressure hydrogen storage tank 18 via a low-pressure hydrogen-side gas drying and purification pipe 16 and a first pressure-stabilizing valve 17.

[0043] The hydrogen production PEM electrolyzer 7 and the electrochemical compressor 15 are the core equipment for producing high-pressure hydrogen.

[0044] Specifically, the structure of the hydrogen-producing PEM electrolyzer is identical to that of electrolyzers in the prior art. The hydrogen-producing PEM electrolyzer 7 includes bolted end plates, an anode plate, a cathode plate, a diffusion layer, a membrane electrode, and a sealing gasket. The diffusion layer is positioned between the electrode plate and the membrane electrode catalyst layer. Fluid channels are defined within the end plates and the electrode plate. The membrane electrode comprises an anode catalyst layer, a proton exchange membrane, and a cathode catalyst layer, arranged in sequence. The fluid channel in the hydrogen-producing PEM electrolyzer 7 is divided into two regions by the membrane electrode and the sealing gasket. The region in contact with the anode catalyst layer is the oxygen-producing side, and the region in contact with the cathode catalyst layer is the hydrogen-producing side.

[0045] See also Figure 2 The electrochemical compressor 15 includes a cathode end plate 24, a cathode plate 25, a first cathode titanium felt 26, a first membrane electrode 27, a first anode titanium felt 28, a first gasket 29, a bipolar plate 30, a second cathode titanium felt 31, a second membrane electrode 32, a second gasket 33, a second anode titanium felt 34, an anode plate 35 and an anode end plate 36, which are connected in sequence by bolts; the first membrane electrode 27 and the second membrane electrode 32 both include a proton exchange membrane and a catalyst layer, the catalyst layer in contact with the low-pressure hydrogen is the anode catalyst layer, and the catalyst layer in contact with the high-pressure hydrogen is the cathode catalyst layer.

[0046] Fluid channels are provided inside the cathode plate 25, the anode plate 35 and the bipolar plate 30. The fluid channels are divided into two areas by the first membrane electrode 27, the second membrane electrode 32 and the first gasket 29 and the second gasket 33. The area in contact with the anode catalyst layer of the first membrane electrode 27 and the second membrane electrode 32 is the low-pressure hydrogen side, and the area in contact with the cathode catalyst layer of the first membrane electrode 27 and the second membrane electrode 32 is the high-pressure hydrogen side.

[0047] The electrochemical compressor 15 drives hydrogen compression through a potential difference. Its operating principle is as follows: After hydrogen enters the anode chamber of the electrochemical compressor 15, the hydrogen molecules pass through the gas diffusion layer to the catalyst layer. An oxidation reaction occurs at the three-phase interface of the reactant gas, catalyst, and proton exchange membrane, oxidizing the hydrogen molecules into protons and electrons. Subsequently, under the action of an applied voltage, the protons are transferred through the proton exchange membrane to the cathode, while the electrons are conducted through the catalyst layer, the porous gas diffusion layer, and the conductive electrode plate to the external circuit. In the cathode chamber, the protons transferred from the anode through the electrolyte and the electrons transferred through the external circuit combine and recombine to form hydrogen molecules.

[0048] The anode electrode reaction in the anode chamber is as follows:

[0049] H2(Anode)→2H + +2e -

[0050] The cathode electrode reaction in the cathode chamber is as follows:

[0051] 2H + +2e - →H2(Cathode)

[0052] When the hydrogen is dissociated into protons and electrons, high-pressure hydrogen is regenerated on the high-pressure hydrogen side. The high-pressure hydrogen flows from the gas channel in the middle of the electrochemical compressor 15 along the Figure 3 The blue arrow flows out, and the unreacted hydrogen passes through Figure 3 The red arrow flows out.

[0053] Since each single chamber of the electrochemical compressor 15 shares the same gas path, and the crossover of the cathode and anode gases may lead to the risk of high-pressure hydrogen leakage, it is necessary to specially design the gas path and sealing structure of the electrochemical compressor 15. In view of the above problems, the present invention optimizes the sealing structure of the electrochemical compressor 15. The specific structure is as follows: Figure 3 shown.

[0054] Traditional sealing structure designs typically use O-rings to separate the anode and cathode into two enclosed spaces that do not interfere with each other. The present invention improves the arrangement of the O-rings, placing the O-rings for the anode and cathode, respectively, on either side of the first membrane electrode 27 and the second membrane electrode 32, in an alternating arrangement. To streamline the sealing structure design, the present invention only retains one set of sealing components at the cathode and anode positions. To ensure sealing reliability, each sealing point adopts a double insurance design: two cathode sealing rings 37 are provided on the outside of the fluid channel on the cathode plate 25 on the left side of the first membrane electrode 27, and two anode sealing rings 38 are provided on the outside of the gas channel in the middle of the left side wall of the bipolar plate 30 (i.e., the anode side of the bipolar plate 30). Similarly, two second cathode sealing rings 39 are provided on the right side wall of the bipolar plate 30 (i.e., the cathode side of the bipolar plate 30), and two second anode sealing rings 40 are installed on the anode plate 35.

[0055] Figure 3 This is a schematic diagram of the specific sealing structure of the electrochemical compressor 15. If the sealing ring is compressed by both the titanium felt and the electrode plate, the titanium felt will plastically deform, leading to seal failure. To avoid this problem, the present invention employs a first metal spacer 41, a second metal spacer 42, a third metal spacer 43, and a fourth metal spacer 44 to ensure uniform force on the sealing ring and maintain long-term sealing performance.

[0056] In the present invention, a first anode sealing ring 38 is provided on one side of the first membrane electrode 27, and a first metal washer 41 is provided on the other side. The first anode sealing ring 38 and the first metal washer 41 are symmetrically arranged on both sides of the first membrane electrode 27. The first metal washer 41 and the bipolar plate 30 jointly compress the first anode sealing ring 38.

[0057] In the present invention, a first cathode sealing ring 37 is provided on one side of the first membrane electrode 27, and a second metal pad 42 is provided on the other side. The first cathode sealing ring 37 and the second metal pad 42 are symmetrically arranged on both sides of the first membrane electrode 27. The cathode plate 25 and the second metal pad 42 jointly compress the first cathode sealing ring 37.

[0058] In the present invention, a second anode sealing ring 40 is provided on one side of the second membrane electrode 32, and a third metal pad 43 is provided on the other side. The third metal pad 43 and the second anode sealing ring 40 are symmetrically arranged on both sides of the second membrane electrode 32, and the third metal pad 43 and the anode plate 35 jointly press the second anode sealing ring 40.

[0059] In the present invention, a second cathode sealing ring 39 is provided on one side of the second membrane electrode 32, and a fourth metal pad 44 is provided on the other side. The second cathode sealing ring 39 and the fourth metal pad 44 are symmetrically arranged on both sides of the second membrane electrode 32. The bipolar plate 30 and the fourth metal pad 44 jointly compress the second cathode sealing ring 39.

[0060] During the operation of the hydrogen-producing PEM electrolyzer 7, the water supplied from the anode side mixes with the generated oxygen. At the same time, due to the drag effect of protons, the water on the anode side is brought to the cathode side and mixed with the hydrogen generated at the cathode. Gas-liquid separation is required to achieve the collection of hydrogen / oxygen and the recycling of water. Therefore, the system is equipped with an oxygen-producing side gas-liquid separator 9 and a hydrogen-producing side gas-liquid separator 12. The oxygen-producing side gas-liquid separator 9 removes the liquid water from the oxygen and then transports the oxygen to the oxygen storage tank 10 for storage. Similarly, the hydrogen-producing side gas-liquid separator 12 also removes part of the liquid water from the hydrogen and then transports the hydrogen to the low-pressure hydrogen inlet of the electrochemical compressor 15.

[0061] Furthermore, the water tank 1 provides the required water source for the hydrogen-producing PEM electrolyzer 7 , and the circulation pump 5 is responsible for transporting the water in the water tank 1 to the water inlet of the hydrogen-producing PEM electrolyzer 7 through a pipeline for electrolysis.

[0062] Furthermore, by coupling the hydrogen production PEM electrolyzer 7 and the electrochemical compressor 15, a high-pressure hydrogen system is established to achieve continuous production of high-purity and high-pressure hydrogen.

[0063] The present invention also includes a first DC power supply 6 and a second DC power supply 14. The first DC power supply 6 is used to drive the water electrolysis reaction, and the positive and negative electrodes of the first DC power supply 6 are respectively connected to the electrode plates corresponding to the oxygen-producing side and the hydrogen-producing side of the hydrogen-producing PEM electrolyzer 7; the second DC power supply 14 is used to provide hydrogen compression power, and the positive and negative electrodes of the second DC power supply 14 are respectively connected to the anode plate 35 corresponding to the low-pressure hydrogen side and the cathode plate 25 corresponding to the high-pressure hydrogen side of the electrochemical compressor 15.

[0064] As a preferred solution, in order to ensure the dryness of the gas, the system also includes a gas drying and purification tube, which includes a low-pressure hydrogen side gas drying and purification tube 16 and a high-pressure hydrogen side gas drying and purification tube 20. The high-pressure hydrogen side gas drying and purification tube 20 adopts a pressure-resistant design.

[0065] The low-pressure hydrogen side gas drying and purification pipe 16 is arranged between the low-pressure hydrogen outlet of the electrochemical compressor 15 and the low-pressure hydrogen storage tank 18, and the high-pressure hydrogen side gas drying and purification pipe 20 is arranged between the high-pressure hydrogen outlet of the electrochemical compressor 15 and the high-pressure hydrogen storage tank 21.

[0066] The oxygen production outlet, the oxygen production side gas-liquid separator 9 inlet, and the oxygen production side gas-liquid separator 9 liquid outlet are connected to the water inlet on the hydrogen production PEM electrolyzer 7 through the circulation pump 5 to form an oxygen production side loop.

[0067] Optionally, metering pump 2 replenishes deionized water in the oxygen-producing circuit at regular intervals and in fixed quantities based on the rate of electrolyzed water consumption. Circulation pump 5 drives water circulation within the oxygen-producing circuit, connecting the liquid outlet of gas-liquid separator 9 on the oxygen-producing circuit to the water inlet on the oxygen-producing circuit. This allows for water recycling during the electrolysis process, reducing the demand for ultrapure water and lowering operating costs.

[0068] Further optionally, by reasonably designing the gas-liquid separator 12 on the hydrogen production side, it is possible to separate the liquid phase components in the gaseous product, control the water vapor partial pressure in the hydrogen carrier flow, and control the gas phase water content entering the electrochemical compressor 15 through the humidity controller 23, and regulate it within a preset threshold range, thereby optimizing the mass transfer kinetics characteristics of the electrochemical proton migration interface in the electrochemical compressor 15 and improving the efficiency of high-pressure hydrogen production.

[0069] Specifically, the hydrogen from the hydrogen-producing PEM electrolyzer 7 enters the gas-liquid separator 12 for gas-liquid separation. The separated hydrogen then enters the humidity controller 23, which monitors the water vapor content in the hydrogen in real time and regulates the gas-phase water content in the hydrogen within a preset threshold range. This regulation mechanism ensures that the relative humidity of the hydrogen output from the hydrogen-producing PEM electrolyzer 7 is stably maintained within the preset threshold range, ensuring that when the hydrogen enters the electrochemical compressor 15, the proton exchange membrane within it remains fully moistened to promote proton conduction while preventing excessive liquid water from clogging the gas diffusion layer, thereby improving hydrogen pressurization efficiency and reducing energy consumption.

[0070] The present invention is expected to improve the purity of high-pressure hydrogen, while also increasing compression efficiency, reducing system operating costs, and enhancing overall safety, providing a new approach for building a low-cost and high-safety high-pressure hydrogen electrolysis water system.

[0071] The present invention provides a high-pressure hydrogen method using a proton exchange membrane water electrolyzer coupled with an electrochemical compression mechanism based on the above system, comprising the following steps:

[0072] Close the second stop valve 4 and the third stop valve 8, open the first stop valve 3 and the fourth stop valve 11, open the first pressure-stabilizing valve 17 and the second pressure-stabilizing valve 19, start the metering pump 2, and inject deionized water into the oxygen-producing side gas-liquid separator 9. The liquid level of the deionized water in the oxygen-producing side gas-liquid separator 9 is lower than the gas outlet height.

[0073] Close the first stop valve 3 and the dosing pump 2, open the second stop valve 4 and the third stop valve 8, start the circulation pump 5, and set the third pressure regulating valve 22 to the required hydrogen output pressure;

[0074] Connect the positive electrode and negative electrode of the first DC power supply 6 to the anode plate and cathode plate of the hydrogen production PEM electrolyzer 7 through wires; connect the positive electrode and negative electrode of the second DC power supply 14 to the anode plate and cathode plate of the electrochemical compressor 15 through wires;

[0075] The first DC power supply 6 is started, and water is oxidized on the anode side of the hydrogen production PEM electrolyzer 7 to generate oxygen and hydrogen ions. The hydrogen ions are transferred to the cathode side through the membrane electrode under the action of the electric field and are reduced to hydrogen;

[0076] The hydrogen flows out from the hydrogen production outlet of the electrolyzer 7, passes through the hydrogen production side gas-liquid separator 12 to control the humidity of the hydrogen, and then enters the electrochemical compressor 15;

[0077] The second DC power supply 14 is started, and the hydrogen is oxidized at the anode of the electrochemical compressor 15 to generate hydrogen ions. The hydrogen ions are transferred to the cathode side through the membrane electrode under the action of the electric field and are reduced to hydrogen. The unreacted hydrogen passes through the low-pressure hydrogen side gas drying and purification pipe 16 and enters the low-pressure hydrogen storage tank 18 for storage;

[0078] The generated high-pressure hydrogen flows out from the high-pressure hydrogen outlet of the hydrogen compressor 15, passes through the second pressure stabilizing valve 19 and the high-pressure hydrogen side gas drying and purification pipe 20, and enters the high-pressure hydrogen storage tank 21 for storage;

[0079] As the water electrolysis reaction proceeds, the deionized water is gradually consumed, and the liquid level in the oxygen-producing side gas-liquid separator 9 drops. When the liquid level reaches one-third of the gas outlet height, the first stop valve 3 and the metering pump 2 are opened to replenish the deionized water stored in the water tank 1 to the oxygen-producing side gas-liquid separator 9.

[0080] The above description is merely a description of the preferred embodiment of the present invention and is not to be construed as limiting the claims. The present invention is not limited to the above embodiment, and variations in the specific structure are permitted. Any variations made within the scope of the independent claims of the present invention are also within the scope of protection of the present invention.

[0081] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

Claims

1. A proton exchange membrane water electrolyzer coupled with an electrochemical compression mechanism high-pressure hydrogen system, characterized in that: It comprises a hydrogen production PEM electrolyzer (7), an electrochemical compressor (15) and a gas-liquid separator; Wherein, the hydrogen production PEM electrolyzer (7) is provided with an oxygen production outlet and a hydrogen production outlet; The gas-liquid separator comprises an oxygen-producing side gas-liquid separator (9) and a hydrogen-producing side gas-liquid separator (12); the oxygen-producing outlet is connected to the oxygen-producing side gas-liquid separator (9) inlet, the hydrogen-producing outlet is connected to the hydrogen-producing side gas-liquid separator (12) inlet, and the gas-liquid separator (12) is connected to the electrochemical compressor (15).

2. The proton exchange membrane water electrolyzer coupled electrochemical compression mechanism high-pressure hydrogen system according to claim 1, characterized in that: The electrochemical compressor (15) includes a cathode end plate (24), a cathode plate (25), a first cathode titanium felt (26), a first membrane electrode (27), a first anode titanium felt (28), a first gasket (29), a bipolar plate (30), a second cathode titanium felt (31), a second membrane electrode (32), a second gasket (33), a second anode titanium felt (34), an anode plate (35) and an anode end plate (36) which are arranged in sequence; The cathode plate (25), the anode plate (35) and the bipolar plate (30) are provided with fluid channels, and the fluid channels are divided into two areas by the first membrane electrode (27), the second membrane electrode (32) and the first gasket (29) and the second gasket (33), wherein the area in contact with the anode catalyst layer of the first membrane electrode (27) and the second membrane electrode (32) is the low-pressure hydrogen side, and the area in contact with the cathode catalyst layer of the first membrane electrode (27) and the second membrane electrode (32) is the high-pressure hydrogen side.

3. The proton exchange membrane water electrolyzer coupled electrochemical compression mechanism high-pressure hydrogen system according to claim 2, characterized in that: Sealing rings are provided on both sides of the first membrane electrode (27) and the second membrane electrode (32).

4. The proton exchange membrane water electrolyzer coupled electrochemical compression mechanism high-pressure hydrogen system according to claim 2, characterized in that: A first anode sealing ring (38) is provided on one side of the first membrane electrode (27), and a first metal pad (41) is provided on the other side. The first anode sealing ring (38) and the first metal pad (41) are symmetrically arranged on both sides of the first membrane electrode (27). The first metal pad (41) and the bipolar plate (30) jointly press the first anode sealing ring (38). A first cathode sealing ring (37) is provided on one side of the first membrane electrode (27), and a second metal pad (42) is provided on the other side. The first cathode sealing ring (37) and the second metal pad (42) are symmetrically arranged on both sides of the first membrane electrode (27). The cathode plate (25) and the second metal pad (42) jointly press the first cathode sealing ring (37).

5. The proton exchange membrane water electrolyzer coupled electrochemical compression mechanism high-pressure hydrogen system according to claim 2, characterized in that: A second anode sealing ring (40) is provided on one side of the second membrane electrode (32), and a third metal pad (43) is provided on the other side. The third metal pad (43) and the second anode sealing ring (40) are symmetrically arranged on both sides of the second membrane electrode (32). The third metal pad (43) and the anode plate (35) jointly press the second anode sealing ring (40). A second cathode sealing ring (39) is provided on one side of the second membrane electrode (32), and a fourth metal pad (44) is provided on the other side. The second cathode sealing ring (39) and the fourth metal pad (44) are symmetrically arranged on both sides of the second membrane electrode (32). The bipolar plate (30) and the fourth metal pad (44) jointly press the second cathode sealing ring (39).

6. The proton exchange membrane water electrolyzer coupled electrochemical compression mechanism high-pressure hydrogen system according to claim 1, characterized in that: The system further comprises a first DC power supply (6) and a second DC power supply (14), wherein the positive electrode and the negative electrode of the first DC power supply (6) are respectively connected to the electrode plates corresponding to the oxygen-producing side and the hydrogen-producing side of the hydrogen-producing PEM electrolyzer (7); and the positive electrode and the negative electrode of the second DC power supply (14) are respectively connected to the anode plate (35) and the cathode plate (25) of the electrochemical compressor (15).

7. The proton exchange membrane water electrolyzer coupled electrochemical compression mechanism high-pressure hydrogen system according to claim 1, characterized in that: The hydrogen-producing PEM electrolyzer (7) is connected to a water tank (1), and the outlet of the water tank (1) is connected to the water inlet of the hydrogen-producing PEM electrolyzer (7) via a dosing pump (2), a first stop valve (3), a second stop valve (4), and a circulation pump (5); The system further comprises a gas drying and purification pipe, which comprises a low-pressure hydrogen side gas drying and purification pipe (16) and a high-pressure hydrogen side gas drying and purification pipe (20). The low-pressure hydrogen side gas drying and purification pipe (16) is arranged at the low-pressure hydrogen outlet of the electrochemical compressor (15), and the high-pressure hydrogen side gas drying and purification pipe (20) is arranged at the high-pressure hydrogen outlet of the electrochemical compressor (15).

8. The proton exchange membrane water electrolyzer coupled electrochemical compression mechanism high-pressure hydrogen system according to claim 1, characterized in that: A humidity controller (23) is provided on the pipeline between the gas outlet of the hydrogen production side gas-liquid separator (12) and the electrochemical compressor (15).

9. A high-pressure hydrogen method using a proton exchange membrane water electrolyzer coupled with an electrochemical compression mechanism based on the system of claim 8, characterized in that: The following steps are involved: Water is oxidized on the anode side of the hydrogen production PEM electrolyzer (7) to generate oxygen and hydrogen ions. The hydrogen ions are transferred to the cathode side through the membrane electrode under the action of the electric field and are reduced to hydrogen. The hydrogen flows out from the hydrogen production outlet of the electrolyzer (7), passes through the hydrogen production side gas-liquid separator (12), and then enters the electrochemical compressor (15); The hydrogen gas is oxidized at the anode of the electrochemical compressor (15) to generate hydrogen ions. The hydrogen ions are transferred to the cathode side through the membrane electrode under the action of the electric field and are reduced to hydrogen gas. The unreacted hydrogen gas is discharged from the low-pressure hydrogen outlet of the electrochemical compressor (15); The generated high-pressure hydrogen is discharged from the high-pressure hydrogen outlet of the electrochemical compressor (15).

10. The high-pressure hydrogen method of proton exchange membrane water electrolyzer coupled with electrochemical compression mechanism according to claim 9, characterized in that: The hydrogen in the hydrogen production PEM electrolyzer (7) enters the gas-liquid separator (12) for gas-liquid separation, and the separated hydrogen enters the humidity controller (23), which monitors the water vapor content in the hydrogen in real time, and adjusts the gas phase water content in the hydrogen to be within a preset threshold range through the humidity controller (23).

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