System for desalinating seawater by utilizing recovered waste heat and oxygen of distributed electricity-heat-hydrogen cogeneration system

Abstract

The invention discloses a system for desalinating seawater by utilizing recovered waste heat and oxygen of a distributed electricity-heat-hydrogen cogeneration system. The system comprises a proton exchange membrane electrolytic cell, a 1 # heat exchanger, a 1 # circulating water pump, a hydrogen fuel cell stack, a 2 # heat exchanger, a 2 # circulating water pump, an expansion valve, a filter, a liquid storage tank, a 2 # three-way valve, a condenser, a 1 # three-way valve, a compressor, a hot water storage tank, seawater desalination equipment, an ejector, a water suction pump and a fresh water storage tank. The waste heat recovery subsystem is used for recovering low-temperature waste heat of the distributed electricity-heat-hydrogen cogeneration system in a centralized manner, and a heat source is provided for seawater desalination equipment. The energy comprehensive utilization efficiency of the distributed electricity, heat and hydrogen cogeneration system can be remarkably improved; the low-temperature waste heat is used for seawater desalination, so that the energy consumption and cost of seawater desalination are remarkably reduced; according to the distributed electricity, heat and hydrogen co-production system, electricity-hydrogen-water poly-generation output is achieved, and meanwhile emission of strong brine is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of comprehensive utilization of renewable energy and seawater desalination, and specifically relates to a system for coupling waste heat recovery from a distributed electric, thermal and hydrogen cogeneration system with seawater desalination. Background Art

[0002] Traditional seawater desalination technologies (such as reverse osmosis and multi-effect distillation) have the limitations of high energy consumption and high costs. Distributed electric, thermal and hydrogen cogeneration systems can improve energy efficiency and reduce carbon emissions by integrating renewable energy sources such as wind and light, and combining the synergistic utilization of electricity, heat and hydrogen. Its core is to achieve the conversion between electricity and hydrogen through devices such as electrolyzers and hydrogen fuel cell stacks, and to recover the waste heat during the reaction process. This system can significantly improve the energy efficiency and economy of seawater desalination by recovering waste heat. In recent years, domestic and foreign research institutions and enterprises have conducted research on the "hydrogen-heat-water" cogeneration technology, especially in the field of waste heat recovery coupled with seawater desalination, and have obtained a number of patents.

[0003] Seawater desalination technologies are mainly divided into two categories: thermal and membrane methods. Thermal methods include technologies such as multi-stage flash (MSF), multi-effect evaporation (MED), and low-temperature multi-effect evaporation (LT-MED), while membrane methods mainly include technologies such as reverse osmosis (RO) and electrodialysis (ED). Among them, LT-MED technology has become the preferred technology for waste heat-driven seawater desalination because it requires a low heat source temperature (usually <70°C) and can flexibly match industrial waste heat. Although the cost and energy consumption of these technologies have been greatly reduced through technological advances, these technologies all rely on the consumption of large amounts of fossil energy, which makes the cost of seawater desalination high, and also emits a large amount of CO2 and causes environmental pollution problems. Therefore, clean energy must be used to replace traditional fossil energy.

[0004] Regarding the coupling technology of electric thermal hydrogen cogeneration and seawater desalination, the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences has proposed an innovative system for alkaline water electrolysis to produce hydrogen using negative pressure seawater desalination technology. This system integrates waste heat with low-temperature seawater desalination technology, reducing equipment costs and energy consumption. Huaneng Group has developed a device for combining photovoltaic dynamic electrolysis hydrogen production and seawater desalination. They proposed using photovoltaic power generation for electrolysis hydrogen production and using waste heat for multi-effect distillation seawater desalination to achieve the coupling of renewable energy and seawater desalination. Their device optimizes energy distribution and reduces overall energy consumption through modular design. Patent (CN118724134A) recovers waste heat and waste pressure from alkaline electrolyzers for seawater desalination. Patent (CN220543961U) proposes a waste heat recovery system based on hydrogen fuel cell cogeneration, but they did not consider using the recovered waste heat for seawater desalination to quickly consume the recovered heat energy. The above literature only focuses on the waste heat recovery and utilization of a single hydrogen production electrolyzer or hydrogen fuel cell. There is no report on the waste heat recovery of the entire distributed electric, thermal and hydrogen cogeneration system for seawater desalination. The waste heat (50-100°C) and by-product oxygen of the distributed electric, thermal and hydrogen cogeneration system are not fully utilized, resulting in low comprehensive energy utilization efficiency and heat energy waste in the system.

[0005] Regarding waste heat-driven low-temperature multi-effect distillation (LT-MED) technology, several companies have developed efficient LT-MED systems for waste heat temperatures ranging from 80 to 150°C. Zhuhai Gesheng Technology Co., Ltd. utilizes industrial waste heat or low-grade heat sources from nuclear power plants, combined with a multi-effect evaporation process, to increase water production efficiency by over 20%. This process has been applied in the Bohai New Area's "Green Power to Green Water" project. Changzhou Xinxiang Kerwei Co., Ltd. has developed a new control system that dynamically adjusts the evaporator pressure and temperature to increase the equipment's water production efficiency by 10-15%, making it suitable for distributed cogeneration systems. The LT-MED technology used in the above literature relies on an external vacuum pump to maintain negative pressure. The equipment is complex and energy-intensive, and the evaporation efficiency is not optimized using the byproduct (oxygen) of hydrogen production in the electrolyzer.

[0006] Therefore, there is a need for a system that utilizes the waste heat and oxygen recovered from the distributed electric, thermal and hydrogen cogeneration system to desalinate seawater, so as to improve the comprehensive energy utilization efficiency of the distributed electric, thermal and hydrogen cogeneration technology and promote the commercial application of this technology. Summary of the Invention

[0007] In order to solve at least one technical problem existing in the above background technology, the present invention provides a system for desalinating seawater by recovering waste heat and oxygen from a distributed electric, thermal and hydrogen cogeneration system.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] A system for desalinating seawater by recycling waste heat and oxygen from a distributed electric heat and hydrogen cogeneration system, the system comprising a proton exchange membrane electrolyzer, a 1# heat exchanger, a 1# circulating water pump, a hydrogen fuel cell stack, a 2# heat exchanger, a 2# circulating water pump, an expansion valve, a filter, a liquid storage tank, a 2# three-way valve, a condenser, a 1# three-way valve, a compressor, a hot water storage tank, seawater desalination equipment, an ejector, a water pump, and a fresh water storage tank; the proton exchange membrane electrolyzer is connected to the 1# heat exchanger and the 1# circulating water pump; the hydrogen fuel cell stack is connected to the 2# heat exchanger and the 2# circulating water pump; the condenser, the 1# three-way valve, the 2# three-way valve, the liquid storage tank, the filter, the expansion valve, the 1# heat exchanger and the 2# heat exchanger, the compressor The hot water storage tank is connected to the condenser and the seawater desalination equipment, and external cold water flows into the condenser and comes out as hot water, which is stored in the hot water storage tank. The hot water in the hot water storage tank is used as a low-grade heat source to drive the seawater desalination equipment. At the upper part of the seawater desalination equipment, high-pressure oxygen generated by electrolysis in the proton exchange membrane electrolyzer flows through the ejector to obtain a negative pressure environment, so that the seawater can boil and evaporate to obtain water vapor at a lower temperature; the water pump extracts seawater / brackish water / industrial wastewater to feed the seawater desalination equipment, and after evaporation, it is extracted as high-concentration brine, which can be used to prepare industrial salt; the obtained water vapor is condensed to obtain fresh water, which is stored in the fresh water storage tank.

[0010] Furthermore, the condenser, 1# three-way valve, 2# three-way valve, liquid storage tank, filter, expansion valve, 1# heat exchanger and 2# heat exchanger, compressor, condenser, and hot water storage tank together constitute a waste heat recovery subsystem; the refrigerant used in the waste heat recovery subsystem can be a high-performance refrigerant, or water can be used directly.

[0011] Furthermore, the proton exchange membrane electrolyzer, the hydrogen fuel cell stack and the waste heat recovery subsystem together constitute the distributed electric, thermal and hydrogen cogeneration system.

[0012] Furthermore, the 1# three-way valve and the 2# three-way valve each retain an interface for expanding the application scenarios of waste heat recovery (such as heating).

[0013] Furthermore, the product water of the hydrogen fuel cell stack can be used as a source of fresh water and stored in a fresh water storage tank, thereby facilitating the recycling of fresh water resources.

[0014] Furthermore, the fresh water in the fresh water storage tank can be used as raw material and cooling water for the proton exchange membrane electrolyzer, as well as cooling water for the hydrogen fuel cell stack.

[0015] The present invention also provides a system for desalinating seawater by recycling waste heat and oxygen from a distributed electric thermal hydrogen cogeneration system, and the method is applied to the distributed electric thermal hydrogen cogeneration system coupled with the seawater desalination system as described above; the method comprises: in the distributed electric thermal hydrogen cogeneration system, the heating equipment mainly comprises a proton exchange membrane electrolyzer and a hydrogen fuel cell stack; the proton exchange membrane electrolyzer generates a large amount of heat during the process of hydrogen production by electrolysis, and the 1# circulating water pump pumps cooling water into the proton exchange membrane electrolyzer, and the cooling water takes away the excess heat inside the electrolyzer to maintain the optimal operating temperature; the cooling water at the outlet of the electrolyzer flows into the 1# heat exchanger, and its cooling system is coupled with the waste heat recovery subsystem through the heat exchanger; a high-performance refrigerant is used as the working medium in the waste heat recovery system, and the low-temperature liquid refrigerant in the liquid storage tank flows into the heat exchanger through the filter and the expansion valve, and performs heat exchange with the hot fluid coming out of the electrolyzer, and the hot cold water is used as the working medium. The cooling water becomes cold water again, and the cooling water flows into the proton exchange membrane electrolyzer driven by the 1# circulating water pump, thereby realizing circulating cooling; at the same time, the low-temperature liquid refrigerant becomes a high-temperature, low-pressure gas, and becomes a high-temperature, high-pressure gas after being compressed by the compressor; through the three-way valve, one way enters the water tank condenser and releases heat in the water tank condenser, the refrigerant becomes a low-temperature liquid and flows into the liquid storage tank, thereby realizing the recycling of the refrigerant; the externally supplied cold water absorbs heat through the condenser and becomes hot water, which is stored in the hot water storage tank; the hot water in the hot water storage tank is used as a heat source to heat the seawater desalination equipment to treat high-salt water such as seawater / industrial wastewater and prepare fresh water; the oxygen generated by the proton exchange membrane electrolyzer flows through the ejector and is ejected, so that a negative pressure environment is formed on the upper part of the seawater desalination equipment, so that the seawater can boil and evaporate at a lower temperature to obtain water vapor, and the water vapor is condensed to obtain fresh water, which is stored in the fresh water storage tank.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The low-grade waste heat of the distributed electric-heat-hydrogen cogeneration system is recovered and utilized, significantly optimizing the system's overall energy efficiency. The combined system's electric-to-hydrogen conversion process (hydrogen production electrolyzer) can achieve an electric-to-heat utilization efficiency of over 85%, while the hydrogen-to-electric conversion process (hydrogen fuel cell stacks) can achieve an electric-to-heat utilization efficiency of over 90%.

[0018] (2) Reduced energy consumption and cost of seawater desalination. This technology uses low-grade waste heat generated during electricity and hydrogen production to desalinate seawater instead of using fossil energy. This not only improves energy utilization efficiency but also reduces energy consumption and cost of seawater desalination.

[0019] (3) Modular design: The modular design of this technology supports small-scale, distributed deployment and is suitable for scenarios such as islands and coastal industrial areas.

[0020] (4) It has the advantage of resource recycling. The distributed electric heat and hydrogen cogeneration system realizes the output of electricity, hydrogen and water, while reducing the discharge of concentrated brine. The obtained fresh water can be used as raw material and cooling water for proton exchange membrane electrolyzers; the product water of hydrogen fuel cell stacks can also be used as a source of fresh water and stored in fresh water storage tanks, realizing the recycling of water resources. At the same time, the by-products after seawater desalination can be used to prepare industrial salt, forming a closed-loop industrial chain.

[0021] (5) The oxygen flow produced as a byproduct of hydrogen production by electrolysis of water is used to replace the mechanical vacuum pump to achieve a negative pressure environment in the evaporation chamber, so that seawater can boil and evaporate to obtain water vapor at a lower temperature, further reducing the cost and energy consumption of seawater desalination. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] One or more embodiments are exemplarily described by corresponding drawings, and these exemplifications do not constitute limitations on the embodiments. Unless otherwise stated, the drawings in the drawings do not constitute proportional limitations.

[0023] Figure 1 Schematic diagram of a system for desalinating seawater by recycling waste heat and oxygen using a distributed electric, thermal and hydrogen cogeneration system according to an embodiment of the present invention.

[0024] In the figure: 1. Proton exchange membrane electrolyzer; 2. 1# heat exchanger; 3. 1# circulating water pump; 4. Hydrogen fuel cell stack; 5. 2# heat exchanger; 6. 2# circulating water pump; 7. Expansion valve; 8. Filter; 9. Liquid storage tank; 10. 2# three-way valve; 11. Condenser; 12. 1# three-way valve; 13. Compressor; 14. Hot water storage tank; 15. Seawater desalination equipment; 16. Ejector; 17. Water pump; 18. Fresh water storage tank. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0026] Existing thermal desalination technologies include multi-stage flash (MSF), multi-effect evaporation (MED), and low-temperature multi-effect evaporation (LT-MED). LT-MED requires a low heat source temperature (typically <70°C) and can flexibly accommodate industrial waste heat, making it the preferred technology for waste heat-driven desalination. While technological advances have significantly reduced the cost and energy consumption of these technologies, they all rely on large amounts of fossil fuels, resulting in high desalination costs, significant CO2 emissions, and environmental pollution. Energy consumption and cost are key issues in desalination. Consequently, multi-stage heat recovery from industrial waste heat has been designed for desalination. These methods enable large-scale desalination with minimal electricity, significantly reducing energy consumption and costs. Currently, industrial waste heat sources include thermal power plants, nuclear power plants, and chemical plants, and these technologies have been adopted globally. However, these waste heat sources are high-temperature. Low-temperature waste heat, below 100°C, has received relatively little attention and remains largely unutilized. In addition, in the LT-MED technology, the seawater desalination equipment 15 needs to be placed in a negative pressure environment. Common methods are to use a vacuum pump or ejector 16 to pump air and reduce the pressure, which consumes a large amount of electricity.

[0027] At the same time, distributed cogeneration systems have become a hot topic in the field of integrated energy systems because they integrate renewable energy sources such as wind and solar power, combining the synergistic utilization of electricity, heat, and hydrogen to improve energy efficiency and reduce carbon emissions. However, it should be noted that the conversion of electricity and hydrogen generates a significant amount of waste heat. On the one hand, core equipment (such as hydrogen electrolyzers and hydrogen fuel cell stacks) requires cooling during operation, typically by introducing cooling water to remove the waste heat to maintain optimal operating temperatures. On the other hand, this waste heat is low-temperature, below 100°C, and is not effectively utilized. Although there have been some reports on waste heat recovery from individual hydrogen electrolyzers or hydrogen fuel cells, there are fewer reports on waste heat recovery from entire distributed cogeneration systems for seawater desalination. In the future, when distributed cogeneration systems are scaled up and widely used, the total amount of low-temperature waste heat they generate will be considerable. Recycling this low-temperature waste heat will further improve the overall energy efficiency of distributed cogeneration systems and significantly promote the commercial application and promotion of this technology. It should also be noted that the large amount of high-pressure oxygen generated by the distributed electric, thermal and hydrogen cogeneration system during production is discharged before it is fully utilized, which also causes a large amount of energy loss.

[0028] In response to the above problems, the present invention proposes a system for desalinating seawater by recovering waste heat and oxygen from a distributed electric, thermal and hydrogen cogeneration system.

[0029] The present invention is described in detail below with reference to specific embodiments.

[0030] The present invention provides a system and method for desalinating seawater by recycling waste heat and oxygen from a distributed electric, thermal and hydrogen cogeneration system. Figure 1 As shown, the system includes a proton exchange membrane electrolyzer 1, a 1# heat exchanger 2, a 1# circulating water pump 3, a hydrogen fuel cell stack 4, a 2# heat exchanger 5, a 2# circulating water pump 6, an expansion valve 7, a filter 8, a liquid storage tank 9, a 2# three-way valve 10, a condenser 11, a 1# three-way valve 12, a compressor 13, a hot water storage tank 14, a seawater desalination device 15, an ejector 16, a water pump 17, and a fresh water storage tank 18; the proton exchange membrane electrolyzer 1 is connected to the 1# heat exchanger 2 and the 1# circulating water pump 3; the hydrogen fuel cell stack 4 is connected to the 2# heat exchanger 5 and the 2# circulating water pump 6; the condenser 11, the 1# three-way valve 12, the 2# three-way valve 10, the liquid storage tank 9, the filter 8, the expansion valve 7, the 1# heat exchanger 2 and the 2# heat exchanger 5, the compressor 13 is connected; the hot water storage tank 14 is connected to the condenser 11 and the seawater desalination equipment 15, and external cold water flows into the condenser 11, and hot water comes out. The hot water is stored in the hot water storage tank 14, and the hot water in the hot water storage tank 14 is used as a low-grade heat source to drive the seawater desalination equipment 15; at the upper part of the seawater desalination equipment 15, the high-pressure oxygen generated by electrolysis in the proton exchange membrane electrolyzer 1 flows through the ejector 16 to realize a negative pressure environment, so that the seawater can boil and evaporate to obtain water vapor at a lower temperature; the water pump 17 extracts seawater / brackish water / industrial wastewater to feed the seawater desalination equipment 15, and after evaporation, it is extracted as high-concentration brine, which can be used to prepare industrial salt; the obtained water vapor is condensed to obtain fresh water, which is stored in the fresh water storage tank 18.

[0031] Among them, the proton exchange membrane electrolyzer 1 is used to produce hydrogen, producing hydrogen and high-pressure oxygen, and the hydrogen is stored as an energy material; part of the obtained oxygen is used as the raw material of the hydrogen fuel cell stack 4, and part is sent to the ejector 16 to create a negative pressure environment for the seawater desalination equipment 15; the hydrogen production process generates a large amount of low-temperature waste heat, which is recovered by the waste heat recovery subsystem (1# heat exchanger 2), and the recovered heat energy is collected in the condenser 11 to heat the supplied cold water, and the generated hot water is stored in the hot water storage tank 14; the hydrogen fuel cell stack 4 is used to generate electricity, consumes hydrogen and oxygen, and generates electricity and water. The water can be stored in the fresh water storage tank 18. During the power generation process A large amount of low-temperature waste heat is also generated, which is recovered by the waste heat recovery subsystem (2# heat exchanger 5). The recovered heat energy is collected in the condenser 11 to heat the supplied cold water, and the generated hot water is stored in the hot water storage tank 14; the hot water storage tank 14 provides a heat source for the seawater desalination equipment 15; the seawater desalination equipment 15 is used to desalinate the seawater / industrial wastewater / brackish water pumped in by the water pump 17 to produce fresh water. The raw water in the seawater desalination equipment 15 is evaporated and then extracted as high-concentration brine, which can be used to prepare industrial salt; the obtained fresh water is stored in the fresh water storage tank 18, most of which is used for fresh water supply, and a small part can be used to provide raw water to the proton exchange membrane electrolyzer 1.

[0032] Furthermore, the condenser 11, 1# three-way valve 12, 2# three-way valve 10, liquid storage tank 9, filter 8, expansion valve 7, 1# heat exchanger 2 and 2# heat exchanger 5, compressor 13, and hot water storage tank 14 together constitute a waste heat recovery subsystem; the refrigerant used in the waste heat recovery subsystem can be a high-performance refrigerant, or water can be used directly.

[0033] Furthermore, the proton exchange membrane electrolyzer 1, the hydrogen fuel cell stack 4 and the waste heat recovery subsystem together constitute a distributed electric, thermal and hydrogen cogeneration system.

[0034] Furthermore, both the 1# three-way valve 12 and the 2# three-way valve 10 retain an interface for expanding the application scenarios of waste heat recovery (such as heating).

[0035] Furthermore, the product water of the hydrogen fuel cell stack 4 can be used as one of the sources of fresh water and stored in the fresh water storage tank 18 to facilitate the recycling of fresh water resources.

[0036] It should be noted that, according to usage requirements, the system can be expanded as follows:

[0037] (1) The hot water storage tank 14 can not only absorb waste heat during the normal operation of the distributed electric heat and hydrogen cogeneration system, but also reversely supply heat and domestic hot water. When the system is started, it heats the interior of the proton exchange membrane electrolyzer 1 and the hydrogen fuel cell stack 4, thereby improving the response speed of the entire system.

[0038] (2) The type of hot water storage tank 14 is not limited, and the type of heat storage medium is not limited;

[0039] (3) The desalination technology used by the desalination equipment 15 is not limited, and multiple-effect evaporation, multi-stage flash evaporation, etc. are all acceptable;

[0040] (4) The raw water used by the seawater desalination equipment 15 is not limited to seawater, industrial wastewater, and brackish water, and any other water source that can be used for purification in this system is also acceptable;

[0041] (5) Both the 1# three-way valve 12 and the 2# three-way valve 10 retain an interface for expanding the application scenarios of waste heat recovery (such as heating);

[0042] (6) The produced fresh water is stored in the fresh water storage tank 18. Its use is not limited and it can be used as raw water for electrolytic hydrogen production, cooling water or other production and living water.

[0043] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made based on the essence of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A system for desalinating seawater by recycling waste heat and oxygen from a distributed electric, thermal and hydrogen cogeneration system, characterized in that: The system comprises a proton exchange membrane electrolyzer (1), a No. 1 heat exchanger (2), a No. 1 circulating water pump (3), a hydrogen fuel cell stack (4), a No. 2 heat exchanger (5), a No. 2 circulating water pump (6), an expansion valve (7), a filter (8), a liquid storage tank (9), a No. 2 three-way valve (10), a condenser (11), a No. 1 three-way valve (12), a compressor (13), a hot water storage tank (14), a seawater desalination device (15), an ejector (16), a water pump (17), and a fresh water storage tank (18); The condenser (11), the 1# three-way valve (12), the 2# three-way valve (10), the liquid storage tank (9), the filter (8), the expansion valve (7), the 1# heat exchanger (2), the 2# heat exchanger (5), the compressor (13) and the hot water storage tank (14) together constitute a waste heat recovery subsystem; the working fluid used in the waste heat recovery subsystem is either a refrigerant or water; The proton exchange membrane electrolyzer (1), the hydrogen fuel cell stack (4) and the waste heat recovery subsystem together constitute a distributed electric, thermal and hydrogen cogeneration system.

2. The system for desalinating seawater by recycling waste heat and oxygen from a distributed electric, thermal and hydrogen cogeneration system according to claim 1, characterized in that: The proton exchange membrane electrolyzer (1) is used to produce hydrogen, hydrogen and oxygen, and the hydrogen is stored as an energy material; part of the obtained oxygen is used as a raw material for the hydrogen fuel cell stack (4), and part is sent to the ejector (16) to create a negative pressure environment for the seawater desalination equipment (15).

3. The system for desalinating seawater by recycling waste heat and oxygen from a distributed electric, thermal and hydrogen cogeneration system according to claim 1, characterized in that: The hydrogen fuel cell stack (4) is used for power generation, consumes hydrogen and oxygen, and produces electricity and water, and the water is centrally stored in a fresh water storage tank (18).

4. The system for desalinating seawater by recycling waste heat and oxygen from a distributed electric, thermal and hydrogen cogeneration system according to claim 1 is characterized in that: The hot water in the hot water storage tank (14) provides a heat source for the seawater desalination equipment (15).

5. The system for desalinating seawater by recycling waste heat and oxygen from a distributed electric, thermal and hydrogen cogeneration system according to claim 1 is characterized in that: The seawater desalination equipment (15) is used to desalinate water pumped in by the water pump (17) to produce fresh water. After the raw water in the seawater desalination equipment (15) evaporates, it is extracted as high-concentration brine; the obtained fresh water is stored in a fresh water storage tank (18) and is used for fresh water supply and to provide raw water to the proton exchange membrane electrolyzer (1).

6. The system for desalinating seawater by recycling waste heat and oxygen from a distributed electric, thermal and hydrogen cogeneration system according to claim 1 is characterized in that: The proton exchange membrane electrolyzer (1) generates a large amount of low-temperature waste heat during the hydrogen production process. The waste heat is recovered by the 1# heat exchanger (2). The recovered heat energy is collected in the condenser (11) to heat the supplied cold water, and the generated hot water is stored in the hot water storage tank (14).

7. The system for desalinating seawater by recycling waste heat and oxygen from a distributed electric, thermal and hydrogen cogeneration system according to claim 1, characterized in that: The hydrogen fuel cell stack (4) generates a large amount of low-temperature waste heat during the power generation process. The waste heat is recovered by the 2# heat exchanger (5). The recovered heat energy is collected in the condenser (11) to heat the supplied cold water, and the generated hot water is stored in the hot water storage tank (14).

8. The system for desalinating seawater by recycling waste heat and oxygen from a distributed electric, thermal and hydrogen cogeneration system according to claim 1, characterized in that: The product water of the hydrogen fuel cell stack (4) is used as a fresh water source and is stored in a fresh water storage tank (18).

9. The system for desalinating seawater by recycling waste heat and oxygen from a distributed electric, thermal and hydrogen cogeneration system according to claim 1, characterized in that: The fresh water in the fresh water storage tank (18) is used as raw material and cooling water for the proton exchange membrane electrolyzer (1) and cooling water for the hydrogen fuel cell stack (4).

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