A hydrogen production system and method using high-temperature steam electrolysis

Abstract

This invention discloses a medium- and high-temperature steam electrolysis hydrogen production system and method, belonging to the field of hydrogen energy production technology. It includes: a hydrogen production unit, a gas purification unit, a compression and storage unit, a refrigeration and heating unit, and a power supply unit. Through the coordination of these units, efficient electrolysis hydrogen production from medium- and high-temperature waste heat steam and low-energy-consumption compression and storage of the products are achieved. The hydrogen production unit utilizes waste heat steam from a power plant as a heat source and reactant, reducing the electrical energy consumption required for electrolysis; the gas purification unit efficiently purifies the electrolysis products through condensation and gas-liquid separation; the compression and storage unit uses the residual pressure of the input steam to drive a piston for gas compression, avoiding additional high-energy-consumption mechanical compression; the refrigeration and heating unit provides cooling for gas purification and recovers waste heat for heating, realizing the cascade utilization of energy within the system; the power supply unit adopts a wind-solar hybrid power supply mode to provide stable renewable electricity to the system.

Description

Technical Field

[0001] This invention relates to the field of hydrogen energy production technology, and in particular to a medium- and high-temperature steam electrolysis hydrogen production system and method. Background Technology

[0002] The information disclosed in the background section of this invention is intended only to enhance the understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Hydrogen energy, as a clean and efficient secondary energy source, is a core support for the implementation of the "dual-carbon" strategy. Electrolysis of water to produce hydrogen, due to its ability to achieve efficient synergy between green electricity and hydrogen energy, has become a key research focus in green hydrogen production technology. Industrial production generates a large amount of medium- and high-temperature waste heat resources, with steam temperatures from boilers in thermal power plants often around 200°C. If this high-quality waste heat is not effectively utilized, it will lead to serious energy waste and increase carbon emission pressure.

[0004] Electrolysis of water to produce hydrogen is a core technology for green hydrogen energy production, and its efficiency and cost are significantly affected by temperature. While existing low-temperature electrolysis technologies (<100℃) are mature, they suffer from drawbacks such as slow reaction kinetics, high overpotential, and high energy consumption. Furthermore, they struggle to effectively utilize the medium-to-high temperature waste heat steam (around 200℃) emitted from industrial processes (such as boilers in thermal power plants). High-temperature electrolysis technologies (>500℃), represented by solid oxide electrolysis, offer high theoretical efficiency but face challenges such as demanding material requirements, slow system start-up, poor thermomechanical stability, and high costs. Within the 200℃ medium-to-high temperature range, significant technological gaps exist: at this temperature, catalysts are prone to sintering, oxidation, dissolution, or loss due to high temperature, high pressure, and complex gas-liquid mixtures; traditional proton exchange membranes experience a sharp drop in ionic conductivity and a decline in mechanical strength, making them unsuitable for long-term operation. Therefore, efficiently utilizing waste heat steam from thermal power plants to achieve low-energy consumption and high-stability steam electrolysis for hydrogen production has become a key bottleneck in the development of medium-to-high temperature water electrolysis technology. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a medium- and high-temperature steam electrolysis hydrogen production system and method.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect of the present invention, a medium-high temperature steam electrolysis hydrogen production system is provided, comprising: a hydrogen production unit, a gas purification unit, a compression and storage unit, a refrigeration and heating unit, and a power supply unit; The hydrogen production unit includes an electrolyzer shell (24), and a medium-high temperature composite proton exchange membrane (22), a medium-high temperature oxygen evolution catalyst (21), and a medium-high temperature hydrogen evolution catalyst (23) disposed in the electrolyzer shell (24); the electrolyzer shell (24) is provided with a steam inlet and a gas outlet, and the steam inlet is connected to the medium-high temperature steam of the power plant; A gas purification unit includes a condenser connected to the gas outlet of the electrolytic cell housing (24) and a gas-liquid separator connected to the outlet of the condenser; A compression storage unit includes a high-pressure gas storage tank connected to the gas outlet of a gas-liquid separator, and a high-pressure conveyor belt for transferring the pressure of high-temperature steam in a power plant to the high-pressure gas storage tank to compress the gas therein. A refrigeration and heating unit comprising a vapor compression refrigeration system, wherein the evaporator (10) of the vapor compression refrigeration system is connected to the condenser of the gas purification unit to provide cooling capacity, and the condenser I (8) of the vapor compression refrigeration system is used to release heat to the outside. The power supply unit includes a photovoltaic panel (1) and a fan (2) for supplying power to the hydrogen production unit and the cooling and heating unit. The photovoltaic panel (1) and the fan (2) are electrically connected to the hydrogen production unit and the cooling and heating unit.

[0007] In some embodiments of the present invention, the steam inlet of the hydrogen production unit is connected to a steam equalization diversion device (20) for dividing the input high-temperature steam from the power plant into two paths, which are respectively introduced into both sides of the high-temperature composite proton exchange membrane (22) inside the electrolyzer shell (24); The medium-high temperature composite proton exchange membrane (22) is a CsH2PO4-SiP2O7 heterogeneous composite electrolyte membrane, and the medium-high temperature oxygen evolution catalyst (21) is IrO. x / ATO catalyst, wherein the medium- and high-temperature hydrogen evolution catalyst (23) is a Melamine-Pt / CNT catalyst.

[0008] In some embodiments of the present invention, the gas purification unit includes an oxygen purification branch connected to the oxygen outlet of the electrolyzer and a hydrogen purification branch connected to the hydrogen outlet of the electrolyzer. The oxygen purification branch includes a valve V1, a condenser II (15), and a gas-liquid separator I (12) connected in sequence. The hydrogen purification branch includes valve V2, condenser III (16), and gas-liquid separator II (17) connected in sequence.

[0009] In some embodiments of the present invention, the oxygen purification branch further includes a filter device I (13) and a distilled water collection device I (14) connected to the liquid outlet of the gas-liquid separator I (12); the hydrogen purification branch further includes a filter device II (18) and a distilled water collection device II (19) connected to the liquid outlet of the gas-liquid separator II (17). The gas outlet of the gas-liquid separator I (12) is connected to the high-pressure oxygen storage tank (6), and the gas outlet of the gas-liquid separator II (17) is connected to the high-pressure hydrogen storage tank (4).

[0010] In some embodiments of the present invention, the compression storage unit includes a hydrogen compression storage subsystem and an oxygen compression storage subsystem; The hydrogen compression and storage subsystem includes a high-pressure conveyor belt I (3) and a high-pressure hydrogen storage tank (4). One end of the high-pressure conveyor belt I (3) is connected to the high-temperature steam in the power plant, and the other end is connected to the high-pressure hydrogen storage tank (4). The high-pressure conveyor belt I (3) is used to receive the pressure of the high-temperature steam in the power plant and drive the piston device in the high-pressure hydrogen storage tank (4). The oxygen compression and storage subsystem includes a high-pressure conveyor belt II (5) and a high-pressure oxygen storage tank (6). One end of the high-pressure conveyor belt II (5) is connected to the high-temperature steam in the power plant, and the other end is connected to the high-pressure oxygen storage tank (6). The high-pressure conveyor belt II (5) is used to receive the pressure of the high-temperature steam in the power plant and drive the piston device in the high-pressure oxygen storage tank (6).

[0011] In some embodiments of the present invention, both the high-pressure hydrogen storage tank (4) and the high-pressure oxygen storage tank (6) are provided with multiple movable pressure partition plates for storing the compressed high-pressure gas under pressure.

[0012] In some embodiments of the present invention, the vapor compression refrigeration system of the refrigeration and heating unit further includes a compressor (7), a condenser I (8), a throttling device (9), and an evaporator (10), which are connected in sequence to form a refrigerant circulation loop; the system also includes a solar collector (11) connected to the condenser I (8) to recover the heat released therefrom and heating pipes. The heat released by the condenser I (8) can be supplied to the user together with the heat generated by the solar collector (11).

[0013] In some embodiments of the present invention, an oxygen concentration monitor and a hydrogen concentration monitor are provided at the gas outlet of the electrolytic cell shell (24). The concentration monitors are linked with the corresponding valves to open the valves and discharge the gas into the gas purification unit when the gas reaches a preset concentration.

[0014] In some embodiments of the present invention, the high-temperature steam in the power plant flows through high-pressure conveyor belt I (3) and high-pressure conveyor belt II (5) in sequence, enters the steam equalization diversion device (20) and is sent into the electrolytic cell shell (24).

[0015] In a second aspect of the present invention, a method for producing hydrogen by medium- and high-temperature steam electrolysis is provided, comprising the following steps: High-temperature waste heat steam from the power plant is sequentially fed into the high-pressure conveyor belt I (3) and high-pressure conveyor belt II (5) of the compression storage unit, which drive the piston devices of the high-pressure hydrogen storage tank (4) and high-pressure oxygen storage tank (6) for pre-compression preparation. Subsequently, the steam enters the steam equal flow splitting device (20) and is divided into two equal paths, which are fed into both sides of the high-temperature composite proton exchange membrane (22) inside the electrolytic cell shell (24). The photovoltaic panel (1) and fan (2) of the power supply unit are used to power the hydrogen production unit. Under the proton conduction of the medium-high temperature composite proton exchange membrane (22) and the catalysis of the medium-high temperature oxygen evolution catalyst (21) and the medium-high temperature hydrogen evolution catalyst (23), water vapor undergoes electrolysis reaction, oxygen is generated on the anode side and hydrogen is generated on the cathode side. The oxygen concentration monitor and hydrogen concentration monitor installed at the gas outlet of the electrolytic cell shell (24) monitor the oxygen and hydrogen concentrations respectively; when the oxygen concentration reaches the preset value, valve V1 is opened to discharge the mixture of oxygen and water vapor into the oxygen purification branch of the gas purification unit; when the hydrogen concentration reaches the preset value, valve V2 is opened to discharge the mixture of hydrogen and water vapor into the hydrogen purification branch of the gas purification unit. In the oxygen purification branch, the mixture of oxygen and water vapor enters the condenser II (15), and the water vapor is condensed into liquid water by using the cooling capacity provided by the evaporator (10) of the refrigeration and heating unit; then the gas-liquid mixture enters the gas-liquid separator I (12), the separated oxygen enters the high-pressure oxygen storage tank (6) from above, and the separated liquid water is filtered and stored in sequence through the filter device I (13) and the distilled water collection device I (14); In the hydrogen purification branch, the mixture of hydrogen and water vapor enters the condenser III (16), and the water vapor is condensed into liquid water using the cooling capacity provided by the evaporator (10). Then the gas-liquid mixture enters the gas-liquid separator II (17), and the separated hydrogen enters the high-pressure hydrogen storage tank (4) from above. The separated liquid water is filtered and stored in sequence through the filter device II (18) and the distilled water collection device II (19). The pressure transmitted by the high-pressure conveyor belts I (3) and II (5) driven by the boiler residual pressure drives the piston devices in the high-pressure hydrogen storage tank (4) and the high-pressure oxygen storage tank (6) respectively, compressing the hydrogen and oxygen entering the tank to a high-pressure state step by step, and storing them by pressure division through the movable pressure partition plate set in the tank; when all the pressure partition plates are used up and the storage tank is full, a new high-pressure hydrogen storage tank (4) or high-pressure oxygen storage tank (6) is replaced. The compressor (7) compresses the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gas. After being condensed and releasing heat in the condenser I (8), the gas is then depressurized by the throttling device (9) to form a low-temperature, low-pressure liquid refrigerant. Finally, the liquid refrigerant evaporates and absorbs heat in the evaporator (10) to provide cooling capacity for the condensers II (15) and III (16). The heat released by the condenser I (8) is recovered and used together with the solar collector (11) for heating or providing domestic hot water.

[0016] The beneficial effects of this invention are as follows: (1) This invention integrates a hydrogen production unit, a gas purification unit, a compression and storage unit, a refrigeration and heating unit, and a power supply unit to form an integrated system that works in concert. This solves the core technical problems in the prior art, such as the inability to efficiently recover medium- and high-temperature waste heat steam for electrolytic hydrogen production, unstable system operation, high energy consumption, and low product processing efficiency. In the hydrogen production unit, the steam inlet of the electrolyzer shell is directly connected to the medium- and high-temperature steam of the power plant, realizing the direct utilization of waste heat steam at around 200°C without additional heating or cooling treatment, effectively recovering industrial waste heat resources and reducing energy waste. At the same time, the medium- and high-temperature composite proton exchange membrane, medium- and high-temperature oxygen evolution catalyst, and medium- and high-temperature hydrogen evolution catalyst installed in the electrolyzer shell are adapted to the operating temperature of 200°C, solving the problems of low conductivity and poor mechanical strength of the existing exchange membrane at this temperature, as well as the easy deactivation and poisoning of the catalyst, ensuring that the electrolysis reaction proceeds efficiently and stably, and reducing the reaction energy barrier and power consumption.

[0017] (2) The gas purification unit is directly connected to the gas outlet of the hydrogen production unit through the cooperation of the condenser and the gas-liquid separator. It can quickly separate the water vapor mixed in the electrolysis products, solve the problem of low purity of electrolysis products and difficulty in direct storage in the existing technology, provide a guarantee for subsequent gas compression storage, and avoid the corrosion and impact of water vapor on subsequent equipment.

[0018] (3) The high-pressure conveyor belt set in the compression storage unit directly uses the pressure of the high-temperature steam in the power plant to drive the piston device in the high-pressure gas storage tank. No additional pressurization equipment is required. This solves the problem of large volume of atmospheric pressure storage and high pressurization energy consumption in existing gas storage, realizes the cascade utilization of waste heat pressure, and further reduces the overall energy consumption of the system.

[0019] (4) The vapor compression refrigeration system of the refrigeration and heating unit is connected to the condenser of the gas purification unit to provide stable cooling capacity for water vapor condensation and ensure the efficiency of gas purification. At the same time, the heat released by condenser I can be directly used externally, realizing the synergy of refrigeration and waste heat recovery, improving the system's energy utilization efficiency, and solving the problem of cooling capacity supply and secondary waste heat recovery in the hydrogen production process.

[0020] (5) The power supply unit adopts a wind-solar complementary power supply mode combining photovoltaic panels and wind turbines, and is electrically connected to the hydrogen production unit and the cooling and heating unit to provide stable renewable energy for system operation. This solves the problems of existing systems relying on traditional power grids, high energy consumption costs, and poor environmental performance. At the same time, it avoids the discontinuity of single photovoltaic or wind power supply, ensuring the continuous and stable operation of the system, which is in line with the energy conservation and emission reduction policy. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the medium-high temperature steam electrolysis hydrogen production system of the present invention.

[0022] In the diagram: 1. Photovoltaic panel; 2. Fan; 3. High-pressure conveyor belt I; 4. High-pressure hydrogen storage tank; 5. High-pressure conveyor belt II; 6. High-pressure oxygen storage tank; 7. Compressor; 8. Condenser I; 9. Throttling device; 10. Evaporator; 11. Solar collector; 12. Gas-liquid separator I; 13. Filter device I; 14. Distilled water collection device I; 15. Condenser II; 16. Condenser III; 17. Gas-liquid separator II; 18. Filter device II; 19. Distilled water collection device II; 20. Steam equal flow splitting device; 21. Medium- and high-temperature oxygen evolution catalyst; 22. Medium- and high-temperature composite proton exchange membrane; 23. Medium- and high-temperature hydrogen evolution catalyst; 24. Electrolyzer shell. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] Example 1 In a typical embodiment of the present invention, a medium-high temperature steam electrolysis hydrogen production system is proposed, such as... Figure 1 As shown, it includes a hydrogen production unit, a gas purification unit, a compression and storage unit, a refrigeration and heating unit, and a power supply unit.

[0025] Hydrogen production unit: It includes an electrolyzer shell (24), and a medium-high temperature composite proton exchange membrane (22), a medium-high temperature oxygen evolution catalyst (21), and a medium-high temperature hydrogen evolution catalyst (23) disposed within the electrolyzer shell (24). The electrolyzer shell (24) is provided with a steam inlet and a gas outlet, and the steam inlet is connected to a 150-250℃ medium-high temperature steam pipeline discharged from the power plant.

[0026] Gas purification unit: It includes an oxygen purification branch connected to the oxygen outlet of the electrolyzer and a hydrogen purification branch connected to the hydrogen outlet of the electrolyzer. The oxygen purification branch includes a valve V1, a condenser II (15), and a gas-liquid separator I (12) connected in sequence. The hydrogen purification branch includes a valve V2, a condenser III (16), and a gas-liquid separator II (17) connected in sequence.

[0027] The compression storage unit includes a hydrogen compression storage subsystem and an oxygen compression storage subsystem. The hydrogen compression storage subsystem includes a high-pressure conveyor belt I (3) and a high-pressure hydrogen storage tank (4). One end of the high-pressure conveyor belt I (3) is connected to the high-temperature steam in the power plant, and the other end is connected to a piston device inside the high-pressure hydrogen storage tank (4). The oxygen compression storage subsystem includes a high-pressure conveyor belt II (5) and a high-pressure oxygen storage tank (6). One end of the high-pressure conveyor belt II (5) is connected to the high-temperature steam in the power plant, and the other end is connected to a piston device inside the high-pressure oxygen storage tank (6).

[0028] Refrigeration and heating unit: It comprises a vapor compression refrigeration system formed by sequentially connecting a compressor (7), condenser I (8), throttling device (9), and evaporator (10). The cooling output end of the evaporator (10) is connected to condenser II (15) and condenser III (16) of the gas purification unit to provide the cooling required for condensing water vapor. The heat output end of the condenser I (8) is connected to the solar collector (11) and heating pipes to recover the heat released during the refrigeration process.

[0029] Power supply unit: It includes a photovoltaic panel (1) and a fan (2), which are electrically connected to the electrolyzer of the hydrogen production unit and the compressor (7) of the refrigeration and heating unit.

[0030] The aforementioned system, through the coordinated operation of a hydrogen production unit, a gas purification unit, a compression and storage unit, a refrigeration and heating unit, and a power supply unit, achieves efficient electrolytic hydrogen production from medium- and high-temperature waste heat steam and low-energy-consumption compression and storage of the products. Specifically, the hydrogen production unit utilizes waste heat steam at approximately 200°C directly input from the power plant as a heat source and reactant, significantly reducing the electrical energy consumption required for electrolysis; the gas purification unit efficiently purifies the electrolysis products through condensation and gas-liquid separation; the compression and storage unit uses the residual pressure of the input steam to drive a piston for gas compression, avoiding additional high-energy-consumption mechanical compression; the refrigeration and heating unit provides cooling for gas purification and recovers waste heat for heating, realizing the cascade utilization of energy within the system; and the power supply unit adopts a wind-solar hybrid power supply mode to provide the system with stable renewable electricity.

[0031] In this embodiment, the steam inlet of the hydrogen production unit is connected to a steam equalization diversion device (20), which is used to divide the high-temperature steam input from the power plant into two equal streams, which are respectively introduced into both sides of the high-temperature composite proton exchange membrane (22) inside the electrolyzer shell (24). This design can ensure pressure balance on both sides of the electrolyzer and avoid membrane damage caused by pressure difference. An oxygen concentration monitor and a hydrogen concentration monitor are installed at the gas outlet of the electrolyzer shell (24). The concentration monitor is linked with the corresponding valve to open the valve when the gas reaches the preset concentration and discharge the gas into the gas purification unit, thereby avoiding unnecessary energy consumption caused by low-concentration gas entering subsequent equipment.

[0032] In this embodiment, the oxygen purification branch further includes a filter device I (13) and a distilled water collection device I (14) connected to the liquid outlet of the gas-liquid separator I (12); the hydrogen purification branch further includes a filter device II (18) and a distilled water collection device II (19) connected to the liquid outlet of the gas-liquid separator II (17). The gas outlet of the gas-liquid separator I (12) is connected to the high-pressure oxygen storage tank (6), and the gas outlet of the gas-liquid separator II (17) is connected to the high-pressure hydrogen storage tank (4). The filter device is used to remove trace amounts of catalyst particles and other impurities that may be carried in the condensate to obtain pure distilled water, which can be recycled by the system.

[0033] In this embodiment, both the high-pressure hydrogen storage tank (4) and the high-pressure oxygen storage tank (6) are equipped with multiple movable pressure partitions for storing the compressed high-pressure gas in stages. These pressure partitions move step by step with the pressure during piston compression, achieving staged compression and dividing the interior of the storage tank into multiple independent chambers. This allows for the separate storage of different batches of gas, improving the flexibility and safety of storage.

[0034] In this embodiment, the high-temperature steam in the power plant flows sequentially through high-pressure conveyor belt I (3) and high-pressure conveyor belt II (5), then enters the steam equalization diversion device (20) and is sent into the electrolytic cell shell (24). This path design realizes the tiered and orderly utilization of steam energy: first, the high pressure of the steam drives the compression storage unit, and then the steam enters the electrolytic cell shell as a heat source and raw material for the electrolysis reaction.

[0035] Furthermore, the medium-high temperature composite proton exchange membrane (22) is a CsH2PO4-SiP2O7 heterogeneous composite electrolyte membrane, and the medium-high temperature oxygen evolution catalyst (21) is IrO. x / ATO catalyst, wherein the medium-to-high temperature hydrogen evolution catalyst (23) is a Melamine-Pt / CNT catalyst. The above material can be prepared by the following method: (1) Preparation of medium- and high-temperature composite proton exchange membrane (CsH2PO4-SiP2O7): First, the SiP2O7 matrix was synthesized: nano-SiO2 and H3PO4 were mixed at a molar ratio of 1:2.5. The mixture was first heat-treated at 200℃ for 3 hours to remove free water from the raw materials, and then calcined at 700℃ for 3 hours to induce a solid-state reaction and generate SiP2O7. The calcined product was then mechanically ball-milled until its average particle size was less than 1 micrometer, and then set aside for use.

[0036] Next, CsH2PO4 was synthesized: A precipitation method was used, dissolving Cs2CO3 and H3PO4 in deionized water at a Cs:P molar ratio of 1:2 and stirring thoroughly. Methanol was then added to the solution to induce the precipitation of CsH2PO4. The resulting precipitate was filtered, washed, and vacuum dried at 80°C for 12 hours to obtain CsH2PO4 powder.

[0037] Finally, the composite membrane was prepared: the CsH2PO4 powder and SiP2O7 powder were accurately weighed and mixed in a molar ratio of 1:2, and then thoroughly ground in a mortar until homogeneous. The mixed powder was placed into a special mold and cold-pressed under a pressure of 200 MPa to obtain a membrane preform. The formed membrane was then placed in an oven at 150-220℃ for annealing to promote chemical bonding between the CsH2PO4 and SiP2O7 phases at the interface, forming a structurally stable composite proton exchange membrane. The resulting membrane thickness was 100-150 micrometers.

[0038] The composite proton exchange membrane prepared by the above method has a thickness of 100-150 micrometers and a proton conductivity exceeding 20 mS / cm in a water vapor environment at 200℃. The SiP2O7 framework provides excellent mechanical strength to the membrane, effectively suppressing plastic creep at high temperatures and ensuring structural stability during long-term operation. By introducing a high specific surface area SiP2O7 nanomatrix, the acidic sites on its surface chemically interact with CsH2PO4, inducing lattice distortion of CsH2PO4 at the phase interface, forming a highly proton-conductive interface layer with "quasi-molten state" characteristics. This interface layer exhibits superproton conductivity above 150℃, thus enabling the composite membrane to possess high proton conductivity at an operating temperature of 200℃.

[0039] (2) Medium and high temperature anode catalyst (IrO x Preparation of ATO: First, the ATO support was synthesized: SnCl4·5H2O and SbCl3 were dissolved in deionized water acidified with dilute hydrochloric acid, controlling the Sb doping ratio to be 10% (atomic ratio). Ozone was continuously bubbled into the solution for 30 minutes for oxidation pretreatment. The solution was then transferred to a high-pressure reactor lined with polytetrafluoroethylene (PTFE) and subjected to hydrothermal reaction at 200°C for 24 hours. After the reaction, the mixture was allowed to cool naturally, and the precipitate was collected by centrifugation. The precipitate was repeatedly washed with deionized water and ethanol, and dried to obtain well-crystallized ATO nanoparticles.

[0040] Next, Ir loading and oxidation: Take 0.1 g of the above ATO powder and ultrasonically disperse it in 50 mL of ethylene glycol. Add 5 mL of 0.05 M H2IrCl6 solution (Ir loading 20 wt%) and 0.1 g of morphology control agent octadecylamine to the dispersion. Heat the mixture to 160 °C under stirring and reflux for 4 hours. Utilize the reducing effect of ethylene glycol to oxidize Ir³. + Dendritic nanostructures were in situ reduced and grown on the surface of an ATO support. After the reaction, the solid product was collected by centrifugation, washed with ethanol, and then calcined in air at 400°C for 30 minutes to form a thin IrO2 shell on the surface metal Ir, finally yielding IrO. x / ATO catalyst.

[0041] The catalyst prepared by this method combines the high stability of the ATO support with that of IrO. x The high intrinsic activity of nanodendritic crystals makes them suitable for long-term OER reactions under solid acid electrolysis conditions at 200℃. The medium-to-high temperature anode catalyst is IrO. x Nanodendritic cells loaded on an ATO support are denoted as IrO. x / ATO. This support exhibits excellent thermodynamic stability under strong acidity and high anodic potential, and its high electronic conductivity is due to Sb 5+ Doping provides the active component IrO. x It has a one-dimensional nanodendritic or nanorod-like structure with high-index crystal planes and abundant surface defect sites, which is beneficial for exposing OER active centers and promoting reaction mass transfer.

[0042] (3) Preparation of medium- and high-temperature cathode catalyst (Melamine-Pt / CNT): First, Pt / CNT synthesis: Multi-walled carbon nanotubes (CNTs) were placed in a mixed acid solution of concentrated nitric acid and concentrated sulfuric acid (volume ratio 1:3) and refluxed at 80°C for 4 hours to introduce oxygen-containing functional groups such as hydroxyl and carboxyl groups onto their surface. The treated CNTs were washed and dried for later use. 0.1 g of the acidified CNTs and a calculated amount of H2PtCl6 (Pt loading of 20 wt%) were co-dispersed in ethylene glycol, and the pH of the slurry was adjusted to 11 with NaOH solution. The mixed slurry was placed in a microwave reactor and rapidly heated to 160°C at 800 W and maintained for 60 seconds to achieve rapid reduction of platinum salt via a microwave-assisted polyol method, yielding a Pt / CNT composite material loaded with highly dispersed platinum nanoparticles (particle size 2-3 nm).

[0043] Secondly, melamine modification: A 10 mM melamine-water / ethanol mixed solution (water to ethanol volume ratio 1:1) was prepared. The above Pt / CNT catalyst was dispersed in this solution and stirred at 70°C for 5 hours to allow melamine molecules to be fully adsorbed onto the surface of Pt nanoparticles. After the reaction, the solution was filtered, washed with ethanol, and vacuum dried at 80°C to obtain the final melamine-modified catalyst Melamine-Pt / CNT. High-temperature calcination was avoided in this process to maintain the integrity of the modified molecule's structure.

[0044] This catalyst significantly enhances the stability and activity of the hydrogen evolution reaction (HER) in a phosphate-containing environment at 200°C by utilizing the high conductivity and corrosion resistance of the CNT support and the selective protective effect of melamine molecules. The multi-walled carbon nanotube support undergoes pre-oxidation treatment, resulting in a surface rich in oxygen-containing functional groups. Melamine molecules adsorb onto the surface of Pt nanoparticles via their nitrogen atoms, forming a porous, network-like monomolecular modification layer. This modification layer selectively allows protons and hydrogen molecules to pass through based on steric hindrance, while effectively blocking the larger H₂PO₄ molecules. - The adsorption of melamine near the active sites of Pt can alleviate phosphate poisoning. Furthermore, the adsorption of melamine may optimize the electronic structure of Pt, promoting hydrogen desorption.

[0045] The composite proton exchange membrane and IrO prepared above were then used. x The ATO anode catalyst and Melamine-Pt / CNT cathode catalyst are combined via spraying or coating processes to assemble a membrane electrode assembly for 200°C steam electrolysis. Tests at 200°C in a steam-saturated atmosphere show that the composite proton exchange membrane exhibits a proton conductivity exceeding 20 mS / cm, high mechanical strength, and no plastic creep. The anode catalyst demonstrates excellent catalytic activity and support stability under strong acidity and high potential. The cathode catalyst effectively resists phosphate anion poisoning and maintains high hydrogen evolution activity. The synergistic action of these three catalysts enables efficient and stable operation of the electrolyzer at 200°C.

[0046] The working principle of the medium-high temperature steam electrolysis hydrogen production system provided in this embodiment is as follows: The high-temperature, high-pressure steam emitted from the power plant first enters the system, flowing sequentially through high-pressure conveyor belt I (3) and high-pressure conveyor belt II (5), driving the piston devices in the high-pressure hydrogen storage tank (4) and high-pressure oxygen storage tank (6) for pre-compression preparation, respectively. Subsequently, the steam enters the steam equal flow splitting device (20), where it is divided into two equal streams, which are then fed into both sides of the high-temperature composite proton exchange membrane (22) inside the electrolyzer shell (24).

[0047] The photovoltaic panel (1) and fan (2) of the power supply unit supply power to the electrolyzer. At an operating temperature of 150-250℃, water vapor undergoes an oxidation reaction on the medium-high temperature oxygen evolution catalyst (21) on the anode side to generate oxygen and hydrogen ions. The hydrogen ions migrate to the cathode side through the medium-high temperature composite proton exchange membrane (22) and are reduced to hydrogen gas on the medium-high temperature hydrogen evolution catalyst (23) on the cathode side.

[0048] The mixture of oxygen and water vapor generated by electrolysis is discharged from the gas outlet on the anode side. When the oxygen concentration monitor detects that the concentration has reached the preset value, valve V1 is opened, and the mixture enters condenser II (15), where it exchanges heat with the cooling energy from evaporator (10), and the water vapor is condensed into liquid water. The gas-liquid mixture then enters gas-liquid separator I (12), where the separated high-purity oxygen enters the high-pressure oxygen storage tank (6), and the liquid water is filtered by filter device I (13) and then stored in distilled water collection device I (14). Similarly, the mixture of hydrogen and water vapor is discharged from the cathode side, condensed by condenser III (16), and separated by gas-liquid separator II (17). The high-purity hydrogen enters the high-pressure hydrogen storage tank (4), and the liquid water is filtered by filter device II (18) and then stored in distilled water collection device II (19).

[0049] The driven high-pressure conveyor belts I (3) and II (5) continuously transmit pressure to the piston device, compressing the hydrogen and oxygen entering the storage tank to a high-pressure state step by step. The movable pressure partition plate inside the tank moves during the compression process to achieve staged compression and separate storage.

[0050] Meanwhile, the refrigeration and heating unit operates: the compressor (7) compresses the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gas, which is then condensed and released heat in condenser I (8), and then depressurized by the throttling device (9) to form a low-temperature, low-pressure liquid refrigerant. Finally, it evaporates and absorbs heat in the evaporator (10), providing cooling capacity for condenser II (15) and condenser III (16). The heat released by condenser I (8) is recovered and used together with the solar collector (11) for heating or providing domestic hot water.

[0051] Example 2 In a typical embodiment of this invention, a method for producing hydrogen by medium- and high-temperature steam electrolysis is provided, which is implemented using the system described in Embodiment 1, and specifically includes the following steps: Step 1, Steam pressure utilization and distribution: The 150-250℃ medium-high temperature waste heat steam discharged from the power plant is sequentially fed into the high-pressure conveyor belt I (3) and high-pressure conveyor belt II (5) of the compression storage unit, which drive the piston devices of the high-pressure hydrogen storage tank (4) and high-pressure oxygen storage tank (6) for pre-compression preparation; then, the steam enters the steam equal flow splitting device (20) and is divided into two equal paths, which are fed into both sides of the medium-high temperature composite proton exchange membrane (22) in the shell of the electrolytic cell (24).

[0052] Step 2, Medium- and High-Temperature Steam Electrolysis: The photovoltaic panel (1) and fan (2) of the power supply unit are used to supply power to the hydrogen production unit, so that the internal temperature of the electrolysis cell shell (24) is maintained at 150-250℃. Under the proton conduction of the medium- and high-temperature composite proton exchange membrane (22) and the catalysis of the medium- and high-temperature oxygen evolution catalyst (21) and the medium- and high-temperature hydrogen evolution catalyst (23), water vapor undergoes an electrolysis reaction, generating oxygen on the anode side and hydrogen on the cathode side.

[0053] Step 3, Gas Concentration Monitoring and Discharge: The oxygen and hydrogen concentrations are monitored by the oxygen concentration monitor and hydrogen concentration monitor installed at the gas outlet of the electrolytic cell shell (24), respectively. When the oxygen concentration reaches the preset value, valve V1 is opened to discharge the mixture of oxygen and water vapor into the oxygen purification branch of the gas purification unit. When the hydrogen concentration reaches the preset value, valve V2 is opened to discharge the mixture of hydrogen and water vapor into the hydrogen purification branch of the gas purification unit.

[0054] Step 4, Oxygen Purification and Separation: In the oxygen purification branch, the mixture of oxygen and water vapor enters the condenser II (15), and the water vapor is condensed into liquid water by using the cooling capacity provided by the evaporator (10) of the refrigeration and heating unit; then the gas-liquid mixture enters the gas-liquid separator I (12), and the separated oxygen enters the high-pressure oxygen storage tank (6) from above. The separated liquid water is filtered and stored in sequence through the filter device I (13) and the distilled water collection device I (14).

[0055] Step 5, Hydrogen purification and separation: In the hydrogen purification branch, the mixture of hydrogen and water vapor enters the condenser III (16), and the water vapor is condensed into liquid water using the cooling capacity provided by the evaporator (10); then the gas-liquid mixture enters the gas-liquid separator II (17), the separated hydrogen enters the high-pressure hydrogen storage tank (4) from above, and the separated liquid water is filtered and stored in sequence through the filter device II (18) and the distilled water collection device II (19).

[0056] Step 6, High-pressure compression storage: Using the pressure transmitted by the high-pressure conveyor belt I (3) and high-pressure conveyor belt II (5) driven in step 1, the piston devices in the high-pressure hydrogen storage tank (4) and high-pressure oxygen storage tank (6) are driven respectively to compress the hydrogen and oxygen entering the tank to a high-pressure state step by step, and the pressure is divided and stored by the movable pressure partition plate set in the tank; when all the pressure partition plates are used up and the storage tank is full, a new high-pressure hydrogen storage tank (4) or high-pressure oxygen storage tank (6) is replaced.

[0057] Step 7, Refrigeration and Waste Heat Recovery: Start the vapor compression refrigeration system of the refrigeration and heating unit. The compressor (7) compresses the low-temperature and low-pressure gaseous refrigerant into a high-temperature and high-pressure gas. After condensing and releasing heat in condenser I (8), the gas is depressurized by the throttling device (9) to form a low-temperature and low-pressure liquid refrigerant. Finally, it evaporates and absorbs heat in the evaporator (10) to provide cooling capacity for condenser II (15) and condenser III (16) in steps 4 and 5. At the same time, the heat released by condenser I (8) is recovered and used together with the solar collector (11) for heating or providing domestic hot water.

[0058] Step 8: System self-sustaining operation: After the system is running stably, the wind-solar hybrid power generation of the power supply unit continuously supplies power to the electrolyzer and compressor; the separated distilled water can be recycled to supplement the generation of water vapor; the hydrogen and oxygen stored under high pressure can be used by the outside world or further utilized.

[0059] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A medium-high temperature steam electrolysis hydrogen production system, characterized in that, include: Hydrogen production unit, gas purification unit, compression and storage unit, refrigeration and heating unit, and power supply unit; The hydrogen production unit includes an electrolyzer shell (24), and a medium-high temperature composite proton exchange membrane (22), a medium-high temperature oxygen evolution catalyst (21), and a medium-high temperature hydrogen evolution catalyst (23) disposed in the electrolyzer shell (24); the electrolyzer shell (24) is provided with a steam inlet and a gas outlet, and the steam inlet is connected to the medium-high temperature steam of the power plant; A gas purification unit includes a condenser connected to the gas outlet of the electrolytic cell housing (24) and a gas-liquid separator connected to the outlet of the condenser; A compression storage unit includes a high-pressure gas storage tank connected to the gas outlet of a gas-liquid separator, and a high-pressure conveyor belt for transferring the pressure of high-temperature steam in a power plant to the high-pressure gas storage tank to compress the gas therein. A refrigeration and heating unit comprising a vapor compression refrigeration system, wherein the evaporator (10) of the vapor compression refrigeration system is connected to the condenser of the gas purification unit to provide cooling capacity, and the condenser I (8) of the vapor compression refrigeration system is used to release heat to the outside. The power supply unit includes a photovoltaic panel (1) and a fan (2) for supplying power to the hydrogen production unit and the cooling and heating unit. The photovoltaic panel (1) and the fan (2) are electrically connected to the hydrogen production unit and the cooling and heating unit.

2. The medium-high temperature steam electrolysis hydrogen production system according to claim 1, characterized in that: The steam inlet of the hydrogen production unit is connected to a steam equalization diversion device (20), which is used to divide the high-temperature steam input from the power plant into two paths, which are respectively introduced into both sides of the high-temperature composite proton exchange membrane (22) inside the electrolyzer shell (24); The medium-high temperature composite proton exchange membrane (22) is a CsH2PO4-SiP2O7 heterogeneous composite electrolyte membrane, and the medium-high temperature oxygen evolution catalyst (21) is IrO. x / ATO catalyst, wherein the medium- and high-temperature hydrogen evolution catalyst (23) is a Melamine-Pt / CNT catalyst.

3. The medium-high temperature steam electrolysis hydrogen production system according to claim 1, characterized in that: The gas purification unit includes an oxygen purification branch connected to the oxygen outlet of the electrolyzer and a hydrogen purification branch connected to the hydrogen outlet of the electrolyzer. The oxygen purification branch includes a valve V1, a condenser II (15), and a gas-liquid separator I (12) connected in sequence. The hydrogen purification branch includes valve V2, condenser III (16), and gas-liquid separator II (17) connected in sequence.

4. The medium-high temperature steam electrolysis hydrogen production system according to claim 3, characterized in that: The oxygen purification branch also includes a filter device I (13) and a distilled water collection device I (14) connected to the liquid outlet of the gas-liquid separator I (12); the hydrogen purification branch also includes a filter device II (18) and a distilled water collection device II (19) connected to the liquid outlet of the gas-liquid separator II (17). The gas outlet of the gas-liquid separator I (12) is connected to the high-pressure oxygen storage tank (6), and the gas outlet of the gas-liquid separator II (17) is connected to the high-pressure hydrogen storage tank (4).

5. The medium-high temperature steam electrolysis hydrogen production system according to claim 1, characterized in that: The compression storage unit includes a hydrogen compression storage subsystem and an oxygen compression storage subsystem; The hydrogen compression and storage subsystem includes a high-pressure conveyor belt I (3) and a high-pressure hydrogen storage tank (4). One end of the high-pressure conveyor belt I (3) is connected to the high-temperature steam in the power plant, and the other end is connected to the high-pressure hydrogen storage tank (4). The high-pressure conveyor belt I (3) is used to receive the pressure of the high-temperature steam in the power plant and drive the piston device in the high-pressure hydrogen storage tank (4). The oxygen compression and storage subsystem includes a high-pressure conveyor belt II (5) and a high-pressure oxygen storage tank (6). One end of the high-pressure conveyor belt II (5) is connected to the high-temperature steam in the power plant, and the other end is connected to the high-pressure oxygen storage tank (6). The high-pressure conveyor belt II (5) is used to receive the pressure of the high-temperature steam in the power plant and drive the piston device in the high-pressure oxygen storage tank (6).

6. The medium-high temperature steam electrolysis hydrogen production system according to claim 5, characterized in that: Both the high-pressure hydrogen storage tank (4) and the high-pressure oxygen storage tank (6) are equipped with multiple movable pressure partition plates for storing compressed high-pressure gas under pressure.

7. The medium-high temperature steam electrolysis hydrogen production system according to claim 1, characterized in that: The vapor compression refrigeration system of the refrigeration and heating unit also includes a compressor (7), a condenser I (8), a throttling device (9) and an evaporator (10), which are connected in sequence to form a refrigerant circulation loop; the system also includes a solar collector (11) connected to the condenser I (8) to recover the heat released therefrom and heating pipes.

8. The medium-high temperature steam electrolysis hydrogen production system according to claim 1, characterized in that: An oxygen concentration monitor and a hydrogen concentration monitor are installed at the gas outlet of the electrolytic cell shell (24). The concentration monitors are linked to the corresponding valves to open the valves and discharge the gas into the gas purification unit when the gas reaches the preset concentration.

9. The medium-high temperature steam electrolysis hydrogen production system according to claim 1, characterized in that: In the power plant, the high-temperature steam flows through high-pressure conveyor belt I (3) and high-pressure conveyor belt II (5) in sequence, then enters the steam equalization diversion device (20) and is sent into the electrolytic cell shell (24).

10. A method for producing hydrogen by medium- and high-temperature steam electrolysis, implemented using the system described in any one of claims 1-9, characterized in that, Includes the following steps: High-temperature waste heat steam from the power plant is sequentially fed into the high-pressure conveyor belt I (3) and high-pressure conveyor belt II (5) of the compression storage unit, which drive the piston devices of the high-pressure hydrogen storage tank (4) and high-pressure oxygen storage tank (6) for pre-compression preparation. Subsequently, the steam enters the steam equal flow splitting device (20) and is divided into two equal paths, which are fed into both sides of the high-temperature composite proton exchange membrane (22) inside the electrolytic cell shell (24). The photovoltaic panel (1) and fan (2) of the power supply unit are used to power the hydrogen production unit. Under the proton conduction of the medium-high temperature composite proton exchange membrane (22) and the catalysis of the medium-high temperature oxygen evolution catalyst (21) and the medium-high temperature hydrogen evolution catalyst (23), water vapor undergoes electrolysis reaction, oxygen is generated on the anode side and hydrogen is generated on the cathode side. The oxygen concentration monitor and hydrogen concentration monitor installed at the gas outlet of the electrolytic cell shell (24) monitor the oxygen and hydrogen concentrations respectively; when the oxygen concentration reaches the preset value, valve V1 is opened to discharge the mixture of oxygen and water vapor into the oxygen purification branch of the gas purification unit; when the hydrogen concentration reaches the preset value, valve V2 is opened to discharge the mixture of hydrogen and water vapor into the hydrogen purification branch of the gas purification unit. In the oxygen purification branch, the mixture of oxygen and water vapor enters the condenser II (15), and the water vapor is condensed into liquid water by using the cooling capacity provided by the evaporator (10) of the refrigeration and heating unit; then the gas-liquid mixture enters the gas-liquid separator I (12), the separated oxygen enters the high-pressure oxygen storage tank (6) from above, and the separated liquid water is filtered and stored in sequence through the filter device I (13) and the distilled water collection device I (14); In the hydrogen purification branch, the mixture of hydrogen and water vapor enters the condenser III (16), and the water vapor is condensed into liquid water using the cooling capacity provided by the evaporator (10). Then the gas-liquid mixture enters the gas-liquid separator II (17), and the separated hydrogen enters the high-pressure hydrogen storage tank (4) from above. The separated liquid water is filtered and stored in sequence through the filter device II (18) and the distilled water collection device II (19). The pressure transmitted by the high-pressure conveyor belts I (3) and II (5) driven by the boiler residual pressure drives the piston devices in the high-pressure hydrogen storage tank (4) and the high-pressure oxygen storage tank (6) respectively, compressing the hydrogen and oxygen entering the tank to a high-pressure state step by step, and storing them by pressure division through the movable pressure partition plate set in the tank; when all the pressure partition plates are used up and the storage tank is full, a new high-pressure hydrogen storage tank (4) or high-pressure oxygen storage tank (6) is replaced. The compressor (7) compresses the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gas. After being condensed and releasing heat in the condenser I (8), the gas is then depressurized by the throttling device (9) to form a low-temperature, low-pressure liquid refrigerant. Finally, the liquid refrigerant evaporates and absorbs heat in the evaporator (10) to provide cooling capacity for the condensers II (15) and III (16). The heat released by the condenser I (8) is recovered and used together with the solar collector (11) for heating or providing domestic hot water.

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