SOEC water electrolysis hydrogen production system based on tower type light condensation and heat collection power generation device and compressed steam refrigeration cycle system

Abstract

The invention discloses an SOEC water electrolysis hydrogen production system based on a tower type light-gathering heat-collecting power generation device and a compressed steam refrigeration cycle system. High-temperature gas at an outlet of an electrolytic bath is used for preheating air and hydrogen entering the electrolytic bath, pure water is heated to become water vapor for electrolysis, and a power generator is driven to generate power; high temperature and heat generated by the tower-type light condensation and heat collection power generation system are supplied to an electrolytic tank of the SOEC water electrolysis system for electrolytic hydrogen production; the compressed steam refrigeration cycle system preheats pure water entering an electrolytic bath of the SOEC water electrolysis system by recovering heat; the SOEC water electrolysis system, the tower-type light condensation and heat collection power generation system and the compressed steam refrigeration circulation system are fully combined, so that an electrolytic bath is always at the optimal operation temperature, the electrolysis efficiency is improved, hydrogen production, heat storage and power generation are successfully and perfectly combined, and the influence of new energy power generation power fluctuation on the whole system is reduced; therefore, the operation stability, reliability and continuity of the whole system are improved.

Description

Technical Field

[0001] This invention belongs to the field of water electrolysis for hydrogen production, specifically relating to an SOEC water electrolysis hydrogen production system based on a tower-type concentrating solar thermal power generation device and a compressed steam refrigeration cycle system. Background Technology

[0002] With my country's energy and environmental problems becoming increasingly prominent, accelerating the green and low-carbon energy transition is imperative. Hydrogen energy, with its high energy density, wide availability, and environmental friendliness, is considered the most ideal clean energy source of this century. Utilizing water electrolysis technology to produce green hydrogen without carbon emissions will play a crucial role. Among the three mainstream water electrolysis hydrogen production technologies, alkaline water electrolysis has achieved commercial application, but it suffers from low current density, poor coupling performance with new energy power generation, and high energy consumption; membrane electrolysis is costly and consumes a large amount of energy. Although high-temperature solid oxide electrolysis (SOEC) technology has not yet been industrialized, SOEC electrolyzers are high-temperature electrolyzers, operating at around 800℃, and electrolyzing high-temperature water vapor. The high operating temperature can accelerate the electrode reaction rate, significantly reducing the overpotential during electrolysis and effectively minimizing energy loss during the electrolysis process. If high-quality waste heat is fully utilized in industrial production, the efficiency of the SOEC water electrolysis hydrogen production system can reach over 85%, greatly reducing the system's energy consumption. Therefore, SOEC water electrolysis for hydrogen production is attracting increasing attention and has become a hot topic in international research and development.

[0003] Using renewable energy to produce green hydrogen enables large-scale, efficient utilization of renewable energy, fully utilizing wind and solar power curtailment, alleviating the contradiction of wind and solar power curtailment, opening up new paths for solving the problem of wind and solar power curtailment, and improving energy utilization efficiency. SOEC electrolyzers operate at very high temperatures, and can be equipped with large-scale solar collectors to provide the necessary heat energy to maintain the electrolyzer's temperature, ensuring it operates at its optimal state. However, solar energy resources are unevenly distributed and affected by natural conditions, resulting in fluctuating power generation. At night or on cloudy days, solar collectors cannot collect heat, thus requiring a good heat storage medium to store heat energy for extended periods, improving the reliability, continuity, and stability of the solar concentrating solar power generation system. Among the four traditional solar concentrating collectors, tower-type solar concentrating collectors can heat the heat storage medium to a suitable temperature, meeting the heat energy quality requirements for SOEC electrolyzer operation. Furthermore, in tower-type concentrated solar power (CSP) systems, molten salt can be used as the heat storage medium. Molten salt has low cost, stable operation, high heat storage density, and long storage time, making it suitable for large-scale medium- and high-temperature heat storage. Currently, SOEC water electrolysis systems lack effective measures to maintain the operating temperature of the SOEC electrolyzer for extended periods.

[0004] Because SOEC electrolyzers operate at very high temperatures, the outlet gas and water vapor temperatures are also very high, resulting in high-quality waste heat. However, in current SOEC water electrolysis systems, the recovery rate of this waste heat is low, leading to significant heat loss. Therefore, a reasonable and effective waste heat recovery process is needed to improve the overall system's energy utilization rate and economic efficiency. Simultaneously, in existing SOEC systems, the temperature of the gas-liquid mixture in the hydrogen gas-liquid separator is very high, causing severe liquid atomization and making gas-liquid separation difficult, thus increasing the consumption of pure water in the system.

[0005] When the oxygen content in the hydrogen at the outlet of the SOEC electrolyzer is relatively high, deoxygenation of the hydrogen is required. The catalyst in the deoxygenation tower of the hydrogen purification unit operates at a high temperature. In order to improve the deoxygenation efficiency of the deoxygenation tower, the hydrogen is usually heated by an electric heater before entering the deoxygenation tower. This process consumes a lot of electrical energy and increases the cost of the entire hydrogen production system.

[0006] In addition, hydrogen is typically dried using molecular sieves. The adsorption on the molecular sieves in the drying tower of the purification unit is physical adsorption. Once saturated, it requires a period of heating and regeneration before adsorption can resume; this process is called the desiccant regeneration process. While the drying tower is in regeneration mode, the hydrogen also needs to be heated to 200°C by an electric heater. The high-temperature hydrogen then passes through the molecular sieve to desorb moisture from it. This process also consumes a significant amount of electrical energy, reducing the system's economic efficiency.

[0007] In summary, existing SOEC water electrolysis hydrogen production systems cannot maintain optimal operating temperatures for extended periods, have low waste heat recovery rates, significant heat loss, poor performance when coupled with renewable energy generation, and consume substantial amounts of electricity and pure water, resulting in low economic efficiency. Summary of the Invention

[0008] To address the problems existing in the current SOEC water electrolysis hydrogen production technology, the present invention aims to provide an SOEC water electrolysis hydrogen production system based on a tower-type concentrating solar thermal power generation device and a compressed steam refrigeration cycle system. This system combines power generation, heat storage, and hydrogen production, improves the electrolysis efficiency of the electrolyzer, and has a high waste heat recovery and utilization rate, low power and pure water consumption, thereby improving the reliability and stability of the system operation.

[0009] To achieve the above objectives, the present invention employs the following technical solution:

[0010] A SOEC water electrolysis hydrogen production system based on a tower-type concentrated solar power generation device and a compressed steam refrigeration cycle system includes an SOEC water electrolysis system, a tower-type concentrated solar power generation system, and a compressed steam refrigeration cycle system.

[0011] The SOEC water electrolysis system electrolyzes some water vapor to obtain hydrogen and oxygen. The high-temperature gas at the anode outlet of the SOEC water electrolysis system is used to preheat the air and hydrogen entering the electrolysis cell. The high-temperature gas at the cathode outlet of the SOEC water electrolysis system is used to heat pure water into water vapor. Some of the water vapor enters the electrolysis cell for electrolysis, and some of the water vapor enters the steam turbine to drive the generator to generate electricity.

[0012] The high-temperature steam generated by the tower-type concentrated solar power generation system is supplied to the electrolyzer of the SOEC water electrolysis system for electrolysis to produce hydrogen. The heat generated is supplied to the electrolyzer to maintain the operating temperature of the electrolyzer, and the electricity generated is supplied to the electrolyzer for operation.

[0013] The compressed steam refrigeration cycle system condenses the water vapor generated by the tower concentrating solar thermal power generation system into water to recover waste heat, and uses the recovered heat to preheat the pure water entering the electrolyzer of the SOEC water electrolysis system.

[0014] Furthermore, the SOEC water electrolysis system includes an electrolyzer, the cathode outlet of which is sequentially connected to a steam superheater, a second evaporator, and a gas-liquid separator; the mixture of high-temperature steam and hydrogen at the cathode outlet of the electrolyzer passes through the steam superheater and the second evaporator for heat exchange and cooling before entering the gas-liquid separator for gas-liquid separation; the hydrogen separated by the gas-liquid separator enters a hydrogen purification device for purification; the hydrogen at the outlet of the hydrogen purification device enters a hydrogen storage tank for storage; and the water separated by the gas-liquid separator returns to the pure water tank.

[0015] The anode outlet of the electrolytic cell is connected in sequence to a gas preheater and a second steam generator. The high-temperature oxygen at the anode outlet of the electrolytic cell is cooled down by heat exchange through the gas preheater and the second steam generator and then discharged into the air.

[0016] Furthermore, it includes an air fan, which is connected to a gas preheater via a pipeline. The air outlet of the gas preheater is connected to the anode inlet of the electrolytic cell. Outside air is pressurized by the air fan and enters the gas preheater from the air inlet, where it exchanges heat with the gas at the anode outlet of the electrolytic cell. The heated air then enters the electrolytic cell from the anode inlet.

[0017] Furthermore, the hydrogen outlet of the hydrogen storage tank is connected to the hydrogen inlet of the gas preheater, the hydrogen outlet of the gas preheater is connected to the cathode inlet of the electrolyzer, and a control valve is provided in the pipeline between the hydrogen storage tank and the gas preheater.

[0018] Furthermore, the electrolyte of the electrolytic cell is yttrium-stabilized zirconium oxide, the anode is a perovskite oxide material, and the cathode is Ni / YSZ porous metal ceramic.

[0019] Furthermore, a precision filter and a circulating water pump are installed on the pipeline connecting the gas-liquid separator and the pure water tank.

[0020] Furthermore, in the aforementioned tower-type concentrating solar power generation system, the tower-type concentrating solar collector, the cold molten salt storage tank, the tower-type concentrating solar collector, the hot molten salt storage tank, and the first steam generator are sequentially connected through pipelines to form a heat generation loop. The molten salt at the outlet of the cold molten salt storage tank increases in temperature after absorbing the energy of sunlight collected by the tower-type concentrating solar collector, and the high-temperature molten salt enters the hot molten salt storage tank through pipelines. The molten salt at the outlet of the hot molten salt storage tank decreases in temperature after passing through the first steam generator, and the low-temperature molten salt enters the cold molten salt storage tank through pipelines.

[0021] The cooling tower outlet is connected to the inlet of the first steam generator via the first feedwater pump. The steam outlet of the first steam generator is connected to the first steam distributor. The outlet of the first steam distributor is divided into two branches. The first branch is connected to the steam inlet of the first turbine. The steam outlet of the first turbine is connected to the steam inlet of the cooling tower. The first turbine is connected to the first generator. The second branch of the outlet of the first steam distributor is connected to the cathode inlet of the electrolytic cell.

[0022] Furthermore, the pure water tank is divided into two branches by a water supply pump. Branch one is connected to the inlet of the first steam generator, and branch two is connected to the inlet of the condenser. The outlet of the condenser is connected to the inlet of the second steam generator, and the steam outlet of the second steam generator is connected to the steam inlet of the steam superheater. The steam outlet of the steam superheater is connected to the second steam distributor. The outlet of the second steam distributor is divided into two branches. One branch is connected to the electric heater and then connected to the cathode inlet of the electrolytic cell. The other branch is connected to the second steam turbine. The steam outlet of the second steam turbine is connected to the steam inlet of the first evaporator. The condensate outlet of the first evaporator is connected to the cold water inlet of the condenser via a second feedwater pump. The second steam turbine is connected to the second generator.

[0023] Furthermore, the compressed vapor refrigeration cycle system includes a condenser. The refrigerant outlet of the condenser is connected to the inlet of a throttle valve via a pipeline. The outlet of the throttle valve is then connected to the refrigerant inlets of the first evaporator and the second evaporator via pipelines. The refrigerant outlets of the first evaporator and the second evaporator are both connected to the refrigerant inlet of the compressor via pipelines. The refrigerant outlet of the compressor is then connected to the refrigerant inlet of the condenser. In the compressed vapor refrigeration cycle system, the refrigerant flows through the first evaporator and the second evaporator to absorb heat before entering the compressor for compression. The refrigerant at the compressor outlet releases heat through the condenser and enters the throttle valve. The refrigerant at the outlet of the throttle valve then enters the evaporator to complete the refrigeration cycle.

[0024] Furthermore, the electricity generated by the SOEC electrolysis system is supplied to the electrolytic cell, electric heater, first feed water pump, second feed water pump, makeup water pump, circulating water pump, compressor and air fan.

[0025] As can be seen from the above technical solutions, the present invention has the following advantages:

[0026] 1. The refrigerant in the first evaporator and the second evaporator cools the steam at the outlet of the second steam turbine and the gas-water mixture at the outlet of the water vapor superheater, respectively, thereby reducing the temperature of the gas-liquid mixture in the gas-liquid separator. The liquid atomization is low, which is more conducive to gas-liquid separation and reduces the water consumption in the system.

[0027] 2. The high-temperature gas at the anode outlet of the electrolytic cell is used to preheat the air and hydrogen, thus avoiding the entry of purge air and hydrogen into the electrolytic cell at low temperatures, which would affect the electrolysis reaction rate.

[0028] 3. The pure water from the pure water tank is preheated by the condenser and then turns into water vapor after exchanging heat with the high-temperature products at the outlet of the electrolytic cell. Some of the water vapor enters the electrolytic cell for electrolysis, making full use of the waste heat generated by electrolysis, reducing the system's heat loss, and improving the heat recovery and utilization rate. At the same time, the system has a high waste heat recovery and utilization rate and low power and pure water consumption.

[0029] 4. After pure water is converted into steam, some of the steam enters the steam turbine to do work and drive the generator to generate electricity, thus improving energy utilization.

[0030] 5. The tower-type concentrating solar thermal power generation system can provide heat, electricity, and high-temperature steam for the SOEC electrolyzer, ensuring its normal operation. Simultaneously, the long thermal storage time of the molten salt ensures stable operation of the SOEC electrolyzer even at night or in extreme weather conditions, keeping the electrolyzer at its optimal operating temperature. This improves the electrolysis efficiency, shortens the start-up time, enhances system stability and continuity, reduces losses caused by hydrogen production fluctuations, and ultimately improves the system's economic benefits.

[0031] 6. Tower-type concentrating solar thermal power generation systems can provide thermal energy for gas purification devices, significantly reducing the cost of gas deoxygenation and gas desiccant regeneration, and reducing electricity consumption.

[0032] 7. The system fully recovers and utilizes the heat energy generated during the operation of the electrolyzer, improving heat energy utilization efficiency. It combines a tower-type concentrating solar thermal power generation system, an SOEC water electrolysis system, and a compressed steam refrigeration cycle system. The electricity generated by the tower-type concentrating solar thermal power generation system can power electric heaters, water pumps, air fans, and compressors, while the stored heat can power the electrolyzer and hydrogen purification unit. The compressed steam refrigeration cycle system can condense water vapor into water, lowering the water temperature, and can also preheat pure water from the pure water tank. This system successfully combines power generation, heat storage, and hydrogen production, ensuring the electrolyzer is always at its optimal operating temperature, improving the electrolysis efficiency. Simultaneously, the system has a high waste heat recovery rate, low electricity and pure water consumption, and improves the reliability and stability of system operation. Attached Figure Description

[0033] Figure 1 This is a flow chart of the SOEC water electrolysis hydrogen production system based on a tower-type concentrating solar thermal power generation device and a compressed steam refrigeration cycle system according to the present invention.

[0034] In the diagram: 1-Cooling tower; 2-First steam distributor; 3-First steam generator; 4-Cold molten salt storage tank; 5-First feed water pump; 6-Pure water tank; 7-Make-up water pump; 8-Tower concentrator; 9-Second feed water pump; 10-First evaporator; 11-Throttle valve; 12-Circulating water pump; 13-Precision filter; 14-Condenser; 15-Gas-liquid separator; 16-Second evaporator; 17-Compressor; 18-Air fan; 19-Hydrogen purification device; 20-Hydrogen storage tank; 21-Control valve; 22-Second steam generator; 23-Gas preheater; 24-Steam superheater; 25-Electrolytic cell; 26-Electric heater; 27-Second steam distributor; 28-Second generator; 29-Second turbine; 30-Hot molten salt storage tank; 31-First generator; 32-First turbine; 33-Power grid. Detailed Implementation

[0035] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0036] like Figure 1 As shown, the present invention is an SOEC water electrolysis hydrogen production system based on a tower-type concentrating solar thermal power generation device and a compressed steam refrigeration cycle system. The system includes an SOEC water electrolysis system, a tower-type concentrating solar thermal power generation system, and a compressed steam refrigeration cycle system.

[0037] The SOEC water electrolysis system mainly includes a pure water tank 6, a makeup water pump 7, a second feed water pump 9, a circulating water pump 12, a precision filter 13, a gas-liquid separator 15, an air fan 18, a hydrogen purification device 19, a hydrogen storage tank 20, a control valve 21, a second steam generator 22, a gas preheater 23, a steam superheater 24, an electrolytic cell 25, an electric heater 26, a second steam distributor 27, a second generator 28, and a second steam turbine 29.

[0038] The cathode outlet of the electrolytic cell 25 is sequentially connected to a steam superheater 24, a second evaporator 16, and a gas-liquid separator 15. The mixture of high-temperature steam and hydrogen at the cathode outlet of the electrolytic cell 25 is cooled by heat exchange in the steam superheater 24 and then enters the second evaporator 16 for further cooling. The gas-liquid mixture at the outlet of the second evaporator 16 enters the gas-liquid separator 15 for gas-liquid separation. The hydrogen separated by the gas-liquid separator 15 enters a hydrogen purification device 19 for purification, and the hydrogen at the outlet of the hydrogen purification device 19 enters a hydrogen storage tank 20 for storage. The water separated by the gas-liquid separator 15 passes through a precision filter 13 to remove impurities and then returns to the pure water tank 6 via a circulating water pump 12. The hydrogen purification device 19 includes a hydrogen deoxygenation device and a hydrogen drying device. When the oxygen content in the hydrogen at the inlet of the hydrogen purification device 19 meets the standard, the hydrogen directly enters the hydrogen drying device for drying.

[0039] The anode outlet of the electrolytic cell 25 is connected in sequence to a gas preheater 23 and a second steam generator 22. The high-temperature oxygen at the anode outlet of the electrolytic cell 25 is cooled down by heat exchange through the gas preheater 23 and the second steam generator 22 and then discharged into the air.

[0040] The electrolyte in the electrolytic cell 25 is yttrium-stabilized zirconium oxide (YSZ), the anode is a perovskite oxide material, and the cathode is a Ni / YSZ porous metal ceramic.

[0041] Air blower 18 is connected to gas preheater 23 via pipeline. The air outlet of gas preheater 23 is connected to the anode inlet of electrolytic cell 25. Outside air is pressurized by air blower 18 and enters gas preheater 23 through the air inlet, exchanging heat with the gas at the anode outlet of electrolytic cell 25. The heated air then enters electrolytic cell 25 through the anode inlet. The purging air dilutes the oxygen concentration, thereby reducing corrosion of the oxygen treatment components, and also accelerates the removal of oxygen from the anode.

[0042] The hydrogen outlet of the hydrogen storage tank 20 is connected to the hydrogen inlet of the gas preheater 23. The hydrogen outlet of the gas preheater 23 is connected to the cathode inlet of the electrolytic cell 25. A control valve 21 is installed in the pipeline between the hydrogen storage tank 20 and the gas preheater 23. A small amount of hydrogen from the outlet of the hydrogen storage tank 20 enters the gas preheater 23 and exchanges heat with the gas at the anode outlet of the electrolytic cell 25. After being heated, it mixes with the high-temperature superheated steam from the outlets of the electric heater 26 and the first steam distributor 30, and then enters the cathode of the electrolytic cell 25 together. The flow rate of hydrogen from the outlet of the hydrogen storage tank 20 can be adjusted by regulating the control valve 21. The hydrogen content at the cathode inlet of the electrolytic cell 25 is generally 5%-10% of the steam content. The purpose of mixing hydrogen is to ensure a reducing atmosphere at the cathode and prevent the cathode material Ni from being oxidized.

[0043] The tower-type concentrating solar thermal power generation system mainly includes a cooling tower 1, a first steam distributor 2, a first steam generator 3, a cold molten salt storage tank 4, a first feedwater pump 5, a tower-type concentrating solar collector 8, a hot molten salt storage tank 30, a first generator 31, a first steam turbine 32, and a power grid 33. The tower-type concentrating solar thermal power generation system is used to collect heat, generate high-temperature steam, and generate electricity. The heat generated can be supplied to the electrolyzer 25 to maintain its operating temperature, and the high-temperature steam and electricity generated can be supplied to the electrolyzer 25 for hydrogen electrolysis.

[0044] The cold molten salt storage tank 4, the tower-type concentrating solar collector 8, the hot molten salt storage tank 30, and the first steam generator 3 are sequentially connected by pipelines to form a heat generation loop. The molten salt at the outlet of the cold molten salt storage tank 4 absorbs solar energy collected by the tower-type concentrating solar collector 8, causing its temperature to rise. The high-temperature molten salt then enters the hot molten salt storage tank 30 through the pipeline. The molten salt at the outlet of the hot molten salt storage tank 30 decreases in temperature after passing through the first steam generator 3, and the low-temperature molten salt then enters the cold molten salt storage tank 4 through the pipeline.

[0045] The outlet of cooling tower 1 is connected to the inlet of the first steam generator 3 via the first feedwater pump 5. The steam outlet of the first steam generator 3 is connected to the first steam distributor 2. The outlet of the first steam distributor 2 splits into two branches. The first branch is connected to the steam inlet of the first turbine 32. The steam outlet of the first turbine 32 is connected to the steam inlet of cooling tower 1. The first turbine 32 is connected to the first generator 31. The second branch of the outlet of the first steam distributor 2 is connected to the cathode inlet of the electrolytic cell 25.

[0046] The pure water tank 6 is divided into two branches by the makeup water pump 7. Branch one connects to the inlet of the first steam generator 3, and branch two connects to the inlet of the condenser 14. The outlet of the condenser 14 connects to the inlet of the second steam generator 22, and the steam outlet of the second steam generator 22 connects to the steam inlet of the steam superheater 24. The steam outlet of the steam superheater 24 connects to the second steam distributor 27. The outlet of the second steam distributor 27 splits into two branches. One branch connects to the electric heater 26 and then to the cathode inlet of the electrolytic cell 25; the other branch connects to the second steam turbine 29. The steam outlet of the second steam turbine 29 connects to the steam inlet of the first evaporator 10, and the condensate outlet of the first evaporator 10 connects to the cold water inlet of the condenser 14 via the second feed water pump 9. The second steam turbine 29 is connected to the second generator 28.

[0047] The superheated steam from the outlet of the steam superheater 24 enters the second steam distributor 27. The second steam distributor 27 divides the superheated steam from the outlet of the steam superheater 24 into two streams. One stream of superheated steam enters the electric heater 26 to be heated further to increase its temperature. The superheated steam from the outlet of the electric heater 26 mixes with the superheated steam from the outlet of the first steam distributor 2 and a small amount of hydrogen from the outlet of the gas preheater 23 and then enters the cathode of the electrolytic cell 25. The other stream of superheated steam enters the second turbine 29 to drive the second generator 28 to generate electricity. The generated electricity is fed into the power grid 33. The steam from the outlet of the second turbine 29 flows into the first evaporator 10 and is condensed into water. The water passes through the feed water pump 9 and merges with the pure water from the pure water tank 6, and then enters the condenser 14 together.

[0048] The water from the outlet of the first feedwater pump 5 merges with the pure water from the pure water tank 6 and enters the first steam generator 3. There, it exchanges heat with the high-temperature molten salt and becomes steam. The steam then enters the first steam distributor 2. The first steam distributor 2 divides the superheated steam from the outlet of the steam generator 3 into two streams. One stream mixes with the superheated steam from the outlet of the electric heater 26 and a small amount of hydrogen from the outlet of the gas preheater 23, and then enters the cathode of the electrolytic cell 25. The other stream of superheated steam enters the first turbine 32 to drive the first generator 31 to generate electricity, which is then fed into the power grid 33. The steam from the outlet of the first turbine 32 flows into the cooling tower 1 and is condensed into water. The water from the cooling tower outlet, after passing through the first feedwater pump 5, merges with the pure water from the pure water tank 6 and enters the first steam generator 3 together.

[0049] The pure water in the pure water tank 6, after passing through the makeup water pump 7, partially enters the condenser 14 for preheating. The pure water from the outlet of the condenser 14 enters the second steam generator 22, where it exchanges heat with the high-temperature oxygen from the outlet of the gas preheater 23 to become wet saturated steam. The wet saturated steam from the outlet of the second steam generator 22 then enters the steam superheater 24 to exchange heat with the mixture of high-temperature hydrogen and water vapor from the cathode outlet of the electrolytic cell 25 to become superheated steam.

[0050] The SOEC electrolysis system can electrolyze part of the water vapor to obtain hydrogen and oxygen, while another part of the high-temperature water vapor in the system can enter the second steam turbine 29 to do work, thereby driving the second generator 28 to generate electricity. The electricity generated by the first generator 31 and the second generator 28 is fed into the power grid 33. The electricity in the power grid 33 can supply the electrolytic cell 25, the electric heater 26, the first feed water pump 5, the second feed water pump 9, the makeup water pump 7, the circulating water pump 12, the compressor 17, and the air fan 18.

[0051] The heat stored in the molten salt storage tank 30 can be supplied to the electrolytic cell 25 and the hydrogen purification device 19. The heat storage medium in the tower-type concentrator 8 is molten salt. Molten salt, a melt of inorganic salt, is a heat storage medium with high thermal density, low cost, long lifespan, easy adjustment, and good heat transfer and storage performance, capable of storing heat for approximately 15 hours. The tower-type concentrator 8 has a large number of independently movable plane mirrors (heliostats) distributed over a large area of ​​the ground. The heliostats are installed around the central tower, and each heliostat rotates to two directions to track the sun.

[0052] The compressed vapor refrigeration cycle system includes a first evaporator 10, a throttle valve 11, a condenser 14, a second evaporator 16, and a compressor 17. The compressed vapor refrigeration cycle system can condense water vapor into water, lowering the water temperature, and simultaneously preheat pure water from the pure water tank 6. Meanwhile, the electricity generated by the concentrating solar thermal power generation system can power the water pump, compressor 17, air fan 18, and electric heater 26, and the stored heat can also supply the hydrogen purification unit 19.

[0053] The refrigerant outlet of condenser 14 is connected to the inlet of expansion valve 11 via a pipeline. The outlet of expansion valve 11 is then connected to the refrigerant inlets of the first evaporator 10 and the second evaporator 16 via pipelines. The refrigerant outlets of the first evaporator 10 and the second evaporator 16 are both connected to the refrigerant inlet of compressor 17 via pipelines. The refrigerant outlet of compressor 17 is then connected to the refrigerant inlet of condenser 14. In the compression vapor refrigeration cycle system, the refrigerant flows through the first evaporator 10 and the second evaporator 16 to absorb heat before entering compressor 17 for compression. The refrigerant at the outlet of compressor 17 releases heat through condenser 14 and then enters expansion valve 11. The refrigerant at the outlet of expansion valve 11 then enters the evaporator to complete the refrigeration cycle.

[0054] The refrigerant at the outlet of condenser 14 is divided into two streams after passing through throttle valve 11. One stream enters the first evaporator 10 and exchanges heat with the steam at the outlet of the second turbine 29. The other stream enters the second evaporator 16 and exchanges heat with the gas-liquid mixture at the outlet of the water vapor superheater 24. The refrigerant at the outlets of the first evaporator 10 and the second evaporator 16 merge and enter the compressor 17 for compression. The high-temperature refrigerant at the outlet of compressor 17 enters the condenser 14 and exchanges heat with pure water from the pure water tank 6, thus lowering its temperature. The refrigerant in the compressed vapor refrigeration cycle system can be any industrial refrigerant that meets the requirements of this refrigeration cycle.

[0055] Compared to existing technologies, this invention uses refrigerants in the first and second evaporators to cool the steam at the outlet of the second turbine and the gas-water mixture at the outlet of the steam superheater, respectively. This reduces the temperature of the gas-liquid mixture in the gas-liquid separator, resulting in lower liquid atomization and better gas-liquid separation, thus reducing water consumption in the system. The high-temperature gas at the anode outlet of the electrolytic cell is used to preheat air and hydrogen, preventing purge air and hydrogen from entering the electrolytic cell at low temperatures and affecting the electrolysis reaction rate. Pure water from the pure water tank is preheated by the condenser and, after heat exchange with the high-temperature products at the electrolytic cell outlet, becomes water vapor. Part of this water vapor enters the electrolytic cell for electrolysis, fully utilizing the waste heat generated during electrolysis, reducing system heat loss, and improving heat recovery efficiency. After the pure water becomes water vapor, part of it enters the turbine to drive the generator, improving energy utilization. The tower-type concentrating solar thermal power generation system can provide heat, electricity, and high-temperature water vapor for the SOEC electrolytic cell, ensuring its normal operation. Meanwhile, the long thermal storage time of molten salt ensures stable operation of the SOEC electrolyzer at night or in extreme weather conditions, shortens the start-up time of the electrolyzer, improves the stability and continuity of system operation, reduces losses caused by hydrogen production fluctuations, and improves the economic benefits of the system; the tower-type concentrating solar thermal power generation system can provide thermal energy for the gas purification unit, significantly reducing the cost of gas deoxygenation and gas desiccant regeneration, and reducing power consumption.

Claims

1. A SOEC water electrolysis hydrogen production system based on a tower-type concentrating solar thermal power generation device and a compressed steam refrigeration cycle system, characterized in that: This includes SOEC water electrolysis system, tower-type concentrated solar power generation system, and compressed steam refrigeration cycle system; The SOEC water electrolysis system electrolyzes some water vapor to obtain hydrogen and oxygen. The high-temperature gas at the anode outlet of the SOEC water electrolysis system is used to preheat the air and hydrogen entering the electrolysis cell. The high-temperature gas at the cathode outlet of the SOEC water electrolysis system is used to heat pure water into water vapor. Some of the water vapor enters the electrolysis cell for electrolysis, and some of the water vapor enters the steam turbine to drive the generator to generate electricity. The high-temperature steam generated by the tower-type concentrating solar thermal power generation system is supplied to the electrolyzer of the SOEC water electrolysis system for electrolysis to produce hydrogen. The heat generated is supplied to the electrolyzer (25) to maintain the operating temperature of the electrolyzer (25), and the electricity generated is supplied to the electrolyzer (23) for operation. The compressed steam refrigeration cycle system condenses the water vapor generated by the tower concentrating solar thermal power generation system into water to recover waste heat, and uses the recovered heat to preheat the pure water entering the electrolyzer of the SOEC water electrolysis system.

2. The SOEC water electrolysis hydrogen production system based on a tower-type concentrating solar thermal power generation device and a compressed steam refrigeration cycle system as described in claim 1, characterized in that: The SOEC water electrolysis system includes an electrolytic cell (25). The cathode outlet of the electrolytic cell (25) is connected in sequence to a steam superheater (24), a second evaporator (16), and a gas-liquid separator (15). The mixture of high-temperature steam and hydrogen at the cathode outlet of the electrolytic cell (25) passes through the steam superheater (24) and the second evaporator (16) for heat exchange and cooling before entering the gas-liquid separator (15) for gas-liquid separation. The hydrogen separated by the gas-liquid separator (15) enters the hydrogen purification device (19) for purification. The hydrogen at the outlet of the hydrogen purification device (19) enters the hydrogen storage tank (20) for storage. The water separated by the gas-liquid separator (15) returns to the pure water tank (6). The anode outlet of the electrolytic cell (25) is connected in sequence to a gas preheater (23) and a second steam generator (22). The high-temperature oxygen at the anode outlet of the electrolytic cell (25) is cooled down by heat exchange through the gas preheater (23) and the second steam generator (22) and then discharged into the air.

3. The SOEC water electrolysis hydrogen production system based on a tower-type concentrating solar thermal power generation device and a compressed steam refrigeration cycle system as described in claim 2, characterized in that: Includes an air blower (18), which is connected to a gas preheater (23) via a pipeline. The air outlet of the gas preheater (23) is connected to the anode inlet of the electrolytic cell (25). Outside air is pressurized by the air blower (18) and enters the gas preheater (23) through the air inlet. It exchanges heat with the gas at the anode outlet of the electrolytic cell (25). The heated air enters the electrolytic cell (25) through the anode inlet.

4. The SOEC water electrolysis hydrogen production system based on a tower-type concentrating solar thermal power generation device and a compressed steam refrigeration cycle system as described in claim 2, characterized in that: The hydrogen outlet of the hydrogen storage tank (20) is connected to the hydrogen inlet of the gas preheater (23), and the hydrogen outlet of the gas preheater (23) is connected to the cathode inlet of the electrolytic cell (25). A control valve (21) is provided in the pipeline between the hydrogen storage tank (20) and the gas preheater (23).

5. The SOEC water electrolysis hydrogen production system based on a tower-type concentrating solar thermal power generation device and a compressed steam refrigeration cycle system as described in any one of claims 2-4, characterized in that: The electrolyte of the electrolytic cell (25) is yttrium-stabilized zirconium oxide, the anode is a perovskite oxide material, and the cathode is Ni / YSZ porous metal ceramic.

6. The SOEC water electrolysis hydrogen production system based on a tower-type concentrating solar thermal power generation device and a compressed steam refrigeration cycle system as described in claim 5, characterized in that: A precision filter (13) and a circulating water pump (12) are installed on the pipeline connecting the gas-liquid separator (15) and the pure water tank (6).

7. The SOEC water electrolysis hydrogen production system based on a tower-type concentrating solar thermal power generation device and a compressed steam refrigeration cycle system as described in claim 2, characterized in that: The tower-type concentrating solar power generation system, including the tower concentrating solar collector (8), the cold molten salt storage tank (4), the tower concentrating solar collector (8), the hot molten salt storage tank (30), and the first steam generator (3), are connected in sequence through pipelines to form a heat generation loop. The molten salt at the outlet of the cold molten salt storage tank (4) increases in temperature after absorbing the energy of the sunlight collected by the tower concentrating solar collector (8), and the high-temperature molten salt enters the hot molten salt storage tank (30) through pipelines. The molten salt at the outlet of the hot molten salt storage tank (30) decreases in temperature after passing through the first steam generator (3), and the low-temperature molten salt enters the cold molten salt storage tank (4) through pipelines. The outlet of the cooling tower (1) is connected to the inlet of the first steam generator (3) via the first water pump (5). The steam outlet of the first steam generator (3) is connected to the first steam distributor (2). The outlet of the first steam distributor (2) is divided into two branches. The first branch is connected to the steam inlet of the first turbine (32). The steam outlet of the first turbine (32) is connected to the steam inlet of the cooling tower (1). The first turbine (32) is connected to the first generator (31). The second branch of the outlet of the first steam distributor (2) is connected to the cathode inlet of the electrolytic cell (25).

8. The SOEC water electrolysis hydrogen production system based on a tower-type concentrating solar thermal power generation device and a compressed steam refrigeration cycle system as described in claim 7, characterized in that: The pure water tank (6) is divided into two branches by the water supply pump (7). Branch 1 is connected to the inlet of the first steam generator (3), and branch 2 is connected to the inlet of the condenser (14). The outlet of the condenser (14) is connected to the inlet of the second steam generator (22). The steam outlet of the second steam generator (22) is connected to the steam inlet of the steam superheater (24). The steam outlet of the steam superheater (24) is connected to the second steam distributor (27). The outlet of the second steam distributor (27) is divided into two branches. One branch is connected to the electric heater (26) and then connected to the cathode inlet of the electrolytic cell (25). The other branch is connected to the second steam turbine (29). The steam outlet of the second steam turbine (29) is connected to the steam inlet of the first evaporator (10). The condensate outlet of the first evaporator (10) is connected to the cold water inlet of the condenser (14) via the second feed water pump (9). The second steam turbine (29) is connected to the second generator (28).

9. The SOEC water electrolysis hydrogen production system based on a tower-type concentrating solar thermal power generation device and a compressed steam refrigeration cycle system as described in claim 2, characterized in that: The compressed vapor refrigeration cycle system includes a condenser (14). The refrigerant outlet of the condenser (14) is connected to the inlet of the expansion valve (11) through a pipeline. The outlet of the expansion valve (11) is then connected to the refrigerant inlets of the first evaporator (10) and the second evaporator (16) through pipelines. The refrigerant outlets of the first evaporator (10) and the second evaporator (16) are both connected to the refrigerant inlet of the compressor (17) through pipelines. The refrigerant outlet of the compressor (17) is then connected to the refrigerant inlet of the condenser (14). The refrigerant in the compressed vapor refrigeration cycle system flows through the first evaporator (10) and the second evaporator (16) to absorb heat and then enters the compressor (17) for compression. The refrigerant at the outlet of the compressor (17) releases heat through the condenser (14) and then enters the expansion valve (11). The refrigerant at the outlet of the expansion valve (11) then enters the evaporator to complete the refrigeration cycle.

10. The SOEC water electrolysis hydrogen production system based on a tower-type concentrating solar thermal power generation device and a compressed steam refrigeration cycle system as described in claims 3, 6, 7, 8, or 9, characterized in that: The power generated by the SOEC electrolysis system is supplied to the electrolytic cell (25), electric heater (26), first feed water pump (5), second feed water pump (9), makeup water pump (7), circulating water pump (12), compressor (17) and air fan (18).

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