Energy self-consistent method for water electrolysis hydrogen production factory

Abstract

The invention provides an energy self-consistent method for a water electrolysis hydrogen production factory. The energy self-consistent method for the water electrolysis hydrogen production factory comprises the steps that high-temperature electrolyte in an electrolytic bath flows to a gas-liquid separator through a pipeline; the high-temperature electrolyte in the gas-liquid separator flows to the cascade energy storage tank; the cooled electrolyte flows to the electrolytic bath through a circulating pump; wherein gas in the gas-liquid separator flows into the gas diaphragm valve, and finally the gas respectively flows to the hydrogen purification equipment and the oxygen aftertreatment device through the gas diaphragm valve; and the first step heat storage tank is moved to a place needing heat from the water electrolysis hydrogen production side through the movable energy storage vehicle. Waste heat on the two sides of the system is more reasonably allocated through the movable energy storage vehicle, the energy utilization rate is increased, and the technical problem that in the prior art, an energy self-consistent system of an efficient heat utilization water electrolysis hydrogen production factory is lacked is solved.

Description

Technical fields:

[0001] This invention relates to the field of water electrolysis for hydrogen production technology, and in particular to an energy self-sufficiency method for a water electrolysis hydrogen production plant. Background technology:

[0002] Currently, global warming and the related climate crisis have attracted worldwide attention. Cleaner energy carriers should replace traditional fossil fuels to achieve carbon neutrality. Hydrogen-based energy systems are a promising alternative. Hydrogen has wide applications in internal combustion engines, steam turbines, and fuel cells because it can be easily converted into mechanical, thermal, and electrical energy, thus potentially becoming an excellent energy carrier. Hydrogen can also be used in many currently available internal combustion engines with relatively low-cost modifications. Alkaline water electrolysis can produce hydrogen simply, efficiently, and at low cost. High-purity hydrogen is obtained through this process. Utilizing hydrogen as an alternative to existing fuels and resources, combined with environmentally friendly and alternative production technologies, has the potential to significantly advance the pursuit of a sustainable energy future. This versatile energy carrier can be utilized without releasing harmful air pollutants or causing greenhouse gas emissions. However, since the conversion efficiency of hydrogen production through water electrolysis is only 60% to 75%, a considerable portion is converted into thermal energy. To maintain a stable temperature in the electrolyzer, the electrolyte is usually cooled and then recycled back to the electrolyzer. In the compressor station, low-pressure hydrogen needs to be compressed to high pressure, which also generates a lot of heat. In order to reduce the temperature of hydrogen and utilize this heat, it has become a hot issue of concern. Therefore, the recovery and utilization of these two waste heats have been extensively studied.

[0003] There is an urgent need for an energy self-sufficiency method for water electrolysis hydrogen production plants, which would help solve the technical problem of the lack of an energy self-sufficiency system for high-efficiency heat utilization water electrolysis hydrogen production plants in the existing technology. Summary of the Invention:

[0004] In one embodiment, the present invention provides an energy self-sufficiency method for a water electrolysis hydrogen production plant. By using a mobile energy storage vehicle, the waste heat on both sides of the system can be more rationally distributed, thereby improving energy utilization efficiency. This helps to solve the technical problem of the lack of an energy self-sufficiency system for a water electrolysis hydrogen production plant with high-efficiency heat utilization in the prior art.

[0005] The energy self-sufficiency method of the water electrolysis hydrogen production plant includes:

[0006] The high-temperature electrolyte in the electrolytic cell flows to the gas-liquid separator through pipelines;

[0007] The high-temperature electrolyte in the gas-liquid separator flows to the cascade energy storage tank.

[0008] The cooled electrolyte flows to the electrolytic cell via a circulation pump;

[0009] In the gas-liquid separator, the gas flows into the gas diaphragm valve, and finally the gas flows through the gas diaphragm valve to the hydrogen purification equipment and the oxygen post-treatment device respectively.

[0010] The first-stage heat storage tank is moved from the hydrogen production side of water electrolysis to the site where the heat is needed using a mobile energy storage vehicle.

[0011] In one embodiment, the high-temperature hydrogen cooling unit of the compressor station receives municipal water from the high-temperature hydrogen heat exchanger. Part of the water flowing out of the high-temperature hydrogen heat exchanger flows to the cooling tower, and the other part flows to the first water tank. The water in the first water tank flows into the second stage energy storage tank. The high-temperature water flowing out of the stage energy storage tank flows to the second water tank, the third water tank, and the fourth water tank, respectively, and finally the water flows back to the first water tank.

[0012] In one embodiment, the hot water in the fourth water tank is circulated by the fourth water pump into the second evaporator, and the cooled water flows back into the fourth water tank. The liquid in the compression heat pump flows into the compressor after exchanging heat with the high-temperature water in the second evaporator. The compressed gas flows into the second cooler, which cools the gas into liquid and then returns it to the second evaporator through the second throttle valve.

[0013] In one embodiment, the absorption refrigeration unit receives hot water from the third water tank via a circulating third water pump into the generator, and the cooled water flows back into the third water tank. The refrigerant in the absorption refrigeration cycle exchanges heat with the high-temperature water in the generator and then flows into the cooler. The refrigerant flowing out of the cooler flows into the second throttle valve, and the refrigerant after passing through the second throttle valve flows into the first evaporator, thus forming a complete absorption refrigeration cycle process.

[0014] In one embodiment, the organic Rankine cycle power generation unit receives hot water from the second water tank via a first circulating water pump into a heat exchanger, and the cooled water flows into the second water tank. The circulating agent from the organic Rankine cycle power generation side exchanges heat with the high-temperature water in the heat exchanger and then flows into the steam turbine. The circulating agent flowing out of the steam turbine flows into the first cooler, and the circulating agent flows back into the heat exchanger via a second circulating water pump.

[0015] In one embodiment, after the electrolyte in the electrolytic cell of the hydrogen electrolysis unit is energized, the electrolyte is electrolyzed to generate hydrogen and oxygen. Since the electricity cannot be fully used for the electrochemical reaction, the temperature of the electrolyte rises. The gas-liquid mixture enters the gas-liquid separator together. The high-temperature liquid flowing out after the gas-liquid separator provides heat to the cascade heat storage tank. When the temperature controller detects that the temperature at the outlet of the cascade heat storage tank exceeds 75°C, the cooler is activated to cool the electrolyte.

[0016] In one embodiment, the hydrogen production plant needs to compress low-pressure hydrogen into high-pressure hydrogen. During the compression process, a large amount of heat is generated. In order to utilize this heat, municipal water at around 20°C can be flowed into the heat exchanger to cool the high-temperature hydrogen. The water coming out of the heat exchanger will reach around 35°C. A portion of the water flowing out of the heat exchanger is then directed to a cooling tower to achieve the purpose of circulating cooling.

[0017] In one embodiment, another portion flows into the first water tank to utilize this heat. The water flowing out of the first water tank passes through a stepped heat storage tank, and the water temperature will be further increased. This high-temperature water is then sent to the compression heat pump unit, the absorption refrigeration unit, and the organic Rankine cycle power generation unit to drive the normal operation of the unit. The high-temperature water that has been utilized will return to the first water tank, and so on in a continuous cycle.

[0018] In one embodiment, in the compression heat pump unit, the circulating agent absorbs heat and vaporizes into a high-temperature gas in the second evaporator, which is then compressed into a high-temperature, high-pressure gas by the compressor, and the cooler supplies this heat to the heat user.

[0019] In one embodiment, in the absorption refrigeration unit, the refrigerant absorbs heat in the generator and vaporizes into a high-temperature gas. After passing through the second cooler and the second throttle valve, it transforms into a low-temperature, low-pressure liquid. This low-temperature, low-pressure liquid flows to the first evaporator, which supplies this cooling capacity to the user. The liquid flowing out of the first evaporator is absorbed by the absorber. The concentrated solution in the absorber is sent to the generator by a circulating pump, and the dilute solution in the generator enters the absorber. This process is repeated to achieve a refrigeration cycle. In the organic Rankine cycle power generation, the circulating refrigerant absorbs heat in the heat exchanger and vaporizes into a high-temperature gas. The high-temperature gas drives the steam turbine, which in turn drives the generator to provide power to the user. Attached image description:

[0020] Figure 1 This is a schematic diagram of an energy self-sufficiency system for a water electrolysis hydrogen production plant according to one embodiment of the present invention. Specific implementation examples:

[0021] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Various embodiments and features of this application are described herein with reference to the accompanying drawings.

[0023] These and other features of this application will become apparent from the following description of preferred forms of embodiments given as non-limiting examples, with reference to the accompanying drawings.

[0024] It should also be understood that although this application has been described with reference to some specific examples, those skilled in the art can certainly implement many other equivalent forms of this application, which have the features described in the claims and are therefore all within the scope of protection defined herein.

[0025] The above and other aspects, features and advantages of this application will become more apparent when taken in conjunction with the accompanying drawings and in view of the following detailed description.

[0026] Specific embodiments of this application are described below with reference to the accompanying drawings; however, it should be understood that the claimed embodiments are merely examples of this application, which can be implemented in various ways. Well-known and / or repeated functions and structures are not described in detail to ascertain the true intent based on the user's historical operations, and to avoid unnecessary or redundant details that would obscure this application. Therefore, the specific structural and functional details claimed herein are not intended to be limiting, but merely serve as the basis and representative basis for the claims to teach those skilled in the art to use this application in various ways with substantially any suitable detailed structure.

[0027] This specification may use the phrases “in one embodiment,” “in another embodiment,” “in yet another embodiment,” or “in other embodiments,” all of which may refer to one or more of the same or different embodiments according to this application.

[0028] Currently, the waste heat from biomass power generation coupled with alkaline water electrolysis to produce hydrogen mainly consists of the heat from the alkaline solution in the electrolyzer and the waste heat from the high-temperature hydrogen in the compressor station. The recovery and utilization of these two components of waste heat has been extensively studied. This patent designs a heat recovery system to collect the heat from the alkaline solution and the high-temperature hydrogen, thereby reducing dependence on fossil fuel energy resources and mitigating the environmental degradation caused by fossil fuel combustion, ultimately leading to a significant reduction in global carbon dioxide emissions and other air pollutants. Since the temperature of the alkaline solution in the electrolyzer cannot exceed 95℃, the most common method in factories is to cool the alkaline solution down using cooling water through a heat exchanger, which results in a waste of heat. To utilize this heat, this patent designs a mobile cascade phase change energy storage tank. After the alkaline solution passes through this tank, its temperature reaches the required 60 to 70℃, and this heat can be stored. The tank can then be transported by a mobile energy storage vehicle to a factory within 50km for use. A compression heat pump is used to raise the temperature of the heat transfer fluid passing through the tank to a suitable level, achieving adsorbent regeneration and providing a continuous supply of adsorbent for the hydrogen production plant. This heat can also be used in an absorption chiller to provide a cooling source for the hydrogen production plant, or in an organic Rankine cycle power generation system to provide power to the plant, ultimately achieving combined cooling, heating, and power (CCHP) for the hydrogen production plant. Since the water supply temperature in the pipeline network is around 20℃, which is too low, the cooling water after cooling the high-temperature hydrogen at the compressor station can be transported through pipelines to the inlet of the cascade energy storage tank to act as a heat transfer medium, thereby increasing the initial temperature of the heat transfer medium entering the cascade energy storage tank. This patent utilizes a movable cascade phase change energy storage tank to recover and utilize the waste heat from alkaline water electrolysis, and constructs a refrigeration and heat pump system for recovering waste heat. This achieves the goal of maintaining the normal operation of the electrolyzer and reducing dependence on fossil fuel energy resources, ultimately realizing energy self-sufficiency for the hydrogen production plant.

[0029] Figure 1 This is a schematic diagram of an energy self-sufficient system for a water electrolysis hydrogen production plant according to one embodiment of the present invention. Figure 1 As shown, in one embodiment, an energy self-sufficiency system for a water electrolysis hydrogen production plant includes:

[0030] One side of the water electrolysis hydrogen production process includes:

[0031] One electrolytic cell 1;

[0032] A hydrogen purification device 4 is connected to the electrolytic cell 1 via a pipeline;

[0033] An oxygen post-processing device 5 is connected to the electrolytic cell 1 via a pipeline;

[0034] First-stage energy storage tank 6-Ⅰ;

[0035] One energy storage side includes:

[0036] A second-stage energy storage tank 6-II is used to transfer the stored energy of the second-stage energy storage tank 6-I to the second-stage energy storage tank 6-I via a mobile energy storage vehicle 10;

[0037] A first water tank 12 is connected to a cascade energy storage tank 6-II via a pipeline;

[0038] A water and high-temperature hydrogen heat exchanger 11 is used for heat exchange with the first water tank 12.

[0039] In one embodiment, the energy storage side further includes:

[0040] A second water tank 12-I is connected to the first water tank 12;

[0041] First water pump 9-II,

[0042] A heat exchanger 15 introduces water into the second water tank 12-I through a pipeline, and after circulating heat exchange, it flows back to the second water tank 12-I.

[0043] A steam turbine 16 utilizes the high-temperature hot water from a heat exchanger 15;

[0044] A first cooler 8-Ⅳ is connected to the steam turbine 16;

[0045] A second water pump 9-Ⅲ is connected to heat exchanger 15 to return water in the pipeline to heat exchanger 15.

[0046] In one embodiment, the energy storage side further includes:

[0047] A third water tank 12-II is connected to the first water tank 12;

[0048] A third water pump 9-Ⅳ is connected to a third water tank 12-Ⅱ;

[0049] A generator 14 is connected at one end to the third water pump 9-Ⅳ and at the other end to the third water tank 12-Ⅱ;

[0050] An absorber 19 is connected at one end to a generator 14 and at the other end to a generator 14, and is connected in series with a fourth water pump 9-V;

[0051] A first evaporator 13-II is connected to the absorber 19;

[0052] A second cooler 8-Ⅲ is connected in series between absorber 19 and generator 14.

[0053] In one embodiment, the energy storage side further includes:

[0054] A fourth water tank 12-Ⅲ is connected to the first water tank 12;

[0055] A fourth water pump 9-VI is connected to a fourth water tank 12-Ⅲ;

[0056] A second evaporator 13-I, one end of which is connected to a fourth water pump 9-VI;

[0057] A compressor 17 is connected to a second cooler 8-II;

[0058] A second cooler 8-II is connected to the compressor 17. The second cooler 8-II is connected to the second evaporator 13-I. The other end of the second evaporator 13-I is connected to the fourth water tank 12-III.

[0059] In one embodiment, the cascade energy storage tank 6-II is connected to the fourth water tank 12-III.

[0060] In one embodiment, one end of the third water tank 12-II is connected between the cascade energy storage tank 6-II and the fourth water tank 12-III, and the other end of the third water tank 12-II is connected between the first water tank 12 and the fourth water tank 12-III.

[0061] In one embodiment, one end of the second water tank 12-I is connected between the cascade energy storage tank 6-II and the fourth water tank 12-III.

[0062] In one embodiment, the cascade energy storage tank 6-Ⅰ is fed back to the electrolytic cell 1 via a pipeline through the fifth water pump 9-Ⅰ;

[0063] Among them, the pipeline is connected in series with the temperature controller 7.

[0064] In one embodiment, a first throttle valve 18-Ⅲ is also connected between the generator 14 and the absorber 19 via a pipeline;

[0065] A second throttle valve 18-I is connected in series between the second cooler 8-II and the second evaporator 13-I.

[0066] In one embodiment, the water electrolysis hydrogen production side further includes:

[0067] Two gas-liquid separators, 2-Ⅰ and 2-Ⅱ, are connected in series between the electrolytic cell 1 and the hydrogen purification equipment 4, and the oxygen post-treatment device 5, respectively.

[0068] In one embodiment, the present invention also provides an energy self-sufficiency method for a water electrolysis hydrogen production plant, the energy self-sufficiency method for the water electrolysis hydrogen production plant comprising:

[0069] The high-temperature electrolyte in electrolytic cell 1 flows to gas-liquid separator 2 through pipeline;

[0070] The high-temperature electrolyte in the gas-liquid separator 2 flows to the cascade energy storage tank 6-II;

[0071] The cooled electrolyte flows to electrolytic cell 1 via a circulating pump;

[0072] Among them, the gas in the gas-liquid separator 2 flows into the gas diaphragm valve, and finally the gas flows through the gas diaphragm valve to the hydrogen purification device 4 and the oxygen post-treatment device 5 respectively.

[0073] The first-stage heat storage tank 6-Ⅰ is moved from the hydrogen production side of water electrolysis to the site where the heat is required by the mobile energy storage vehicle 10.

[0074] In one embodiment, the high-temperature hydrogen cooling unit of the compressor station receives municipal water from the high-temperature hydrogen heat exchanger 11. Part of the water flowing out of the high-temperature hydrogen heat exchanger 11 flows to the cooling tower, and the other part flows to the first water tank 12. The water in the first water tank 12 flows into the second stage energy storage tank 6-II. The high-temperature water flowing out of the stage energy storage tank 6-II flows to the second water tank 12-I, the third water tank 12-II, and the fourth water tank 12-III, respectively, and finally the water flows back to the first water tank 12.

[0075] In one embodiment, the hot water in the fourth water tank 12-Ⅲ is circulated by the fourth water pump 9-Ⅵ and flows into the second evaporator 13-Ⅰ. The cooled water flows back into the fourth water tank 12-Ⅲ. The liquid in the compression heat pump exchanges heat with the high-temperature water in the second evaporator 13-Ⅰ and flows into the compressor 17. The compressed gas flows into the second cooler 8-Ⅱ. After the second cooler 8-Ⅱ cools the gas into liquid, it returns to the second evaporator 13-Ⅰ through the second throttle valve 18-Ⅰ.

[0076] In one embodiment, the absorption refrigeration unit receives hot water from the third water tank 12-II via a circulating third water pump 9-Ⅳ into the generator 14, and the cooled water flows back into the third water tank 12-II. The refrigerant in the absorption refrigeration cycle exchanges heat with the high-temperature water in the generator 14 and then flows into the cooler 8-Ⅲ. The refrigerant flowing out of the cooler 8-Ⅲ flows into the second throttle valve 18-Ⅱ, and the refrigerant after passing through the second throttle valve 18-Ⅱ flows into the first evaporator 13-Ⅱ, thus constituting a complete absorption refrigeration cycle process.

[0077] In one embodiment, the organic Rankine cycle power generation unit receives hot water from the second water tank 12-I via a circulating first water pump 9-II into a heat exchanger 15, and the cooled water flows into the second water tank 12-I. The circulating agent on the organic Rankine cycle power generation side exchanges heat with the high-temperature water in the heat exchanger 15 and then flows into the steam turbine 16. The circulating agent flowing out of the steam turbine 16 flows into the first cooler 8-IV, and the circulating agent flows back into the heat exchanger 15 via a circulating second water pump 9-III.

[0078] In one embodiment, after the electrolyte in the electrolyzer 1 of the hydrogen electrolysis unit is energized, the electrolyte is electrolyzed to generate hydrogen and oxygen. Since the electricity cannot be fully used for the electrochemical reaction, the temperature of the electrolyte rises. The gas-liquid mixture enters the gas-liquid separator 2 together. The high-temperature liquid flowing out after passing through the gas-liquid separator 2 provides heat to the cascade heat storage tank. When the temperature controller 7 detects that the temperature at the outlet of the cascade heat storage tank exceeds 75°C, the cooler 8-I is activated to cool the electrolyte.

[0079] In one embodiment, the hydrogen production plant needs to compress low-pressure hydrogen into high-pressure hydrogen. During the compression process, a large amount of heat is generated. In order to utilize this heat, municipal water at around 20°C can be flowed into heat exchanger 11 to cool the high-temperature hydrogen. The water coming out of heat exchanger 11 will reach around 35°C. A portion of the water flowing out of heat exchanger 11 is then directed to a cooling tower to achieve the purpose of circulating cooling.

[0080] In one embodiment, another portion flows into the first water tank 12 to utilize this heat. The water flowing out of the first water tank 12 will have its temperature further increased after passing through the stepped heat storage tank. This high-temperature water will be sent to the compression heat pump unit, the absorption refrigeration unit, and the organic Rankine cycle power generation unit to drive the normal operation of the unit. The high-temperature water that has been utilized will return to the first water tank (12) and so on.

[0081] In one embodiment, the circulating agent in the compression heat pump unit absorbs heat and vaporizes into a high-temperature gas in the second evaporator 13-I, which is then compressed into a high-temperature and high-pressure gas by the compressor 17, and the second cooler 8-II supplies this heat to the heat user.

[0082] In one embodiment, in the absorption refrigeration unit, the refrigerant absorbs heat in the generator 14 and vaporizes into a high-temperature gas. After passing through the second cooler 8-Ⅲ and the second throttle valve 18-Ⅱ, it is transformed into a low-temperature, low-pressure liquid. This low-temperature, low-pressure liquid flows to the first evaporator 13-Ⅱ, which supplies this cooling capacity to the users. The liquid flowing out of the first evaporator 13-Ⅱ is absorbed by the absorber 19. The concentrated solution in the absorber 19 is sent to the generator 14 by the circulation pump 9-Ⅴ, and the dilute solution in the generator 14 enters the absorber 19. This process is repeated to achieve a refrigeration cycle. In the organic Rankine cycle power generation, the circulating refrigerant absorbs heat in the heat exchanger 15 and vaporizes into a high-temperature gas. The high-temperature gas drives the steam turbine 16 to operate, and the steam turbine 16 drives the generator to operate, providing power to the users.

[0083] This patent relates to an energy-self-sufficient system for a hydrogen production plant, comprising a water electrolysis hydrogen production unit, a heat storage / release unit, a compressor station cooling high-temperature hydrogen unit, a compression heat pump unit, an absorption refrigeration unit, and an organic Rankine cycle power generation unit. The water electrolysis hydrogen production unit primarily involves electrolyzing alkaline solutions to produce hydrogen and oxygen. The heat storage / release unit stores heat through cascaded energy storage tanks and then transports this heat to the required site using mobile energy storage vehicles. The compression heat pump unit, absorption refrigeration unit, and organic Rankine cycle power generation unit are used to recover waste heat from the electrolyte and heat generated by the high-temperature hydrogen in the compressor station, and respectively provide heat, cooling, and electricity to the outside world.

[0084] The electrolyzer 1, gas-liquid separator 2, cascade energy storage tank 6, temperature controller 7, cooler 8, and circulation pump 9 are connected by electrolyte to form a water electrolysis hydrogen production unit. The high-temperature electrolyte in the electrolyzer 1 flows to the gas-liquid separator 2 through pipelines, and the high-temperature electrolyte in the gas-liquid separator 2 flows to the cascade energy storage tank 6. The cooled electrolyte flows back to the electrolyzer 1 through the circulation pump 9. The gas in the gas-liquid separator 2 flows into the gas diaphragm valve 3, and finally the gas flows through the gas diaphragm valve 3 to the hydrogen purification device 4 and the oxygen post-treatment device 5, respectively.

[0085] The heat storage / release unit uses a mobile energy storage vehicle to move the cascade heat storage tank 6 from the water electrolysis hydrogen production side to the site where heat is needed; the compressor station cooling high-temperature hydrogen unit receives municipal water from the heat exchanger 11, and part of the water flowing out of the heat exchanger 11 flows to the cooling tower, while the other part flows to the water tank 12. The water in the water tank 12 flows into the cascade energy storage tank 6-II, and the high-temperature water flowing out of the cascade energy storage tank 6-II flows to the water tanks 12-I, 12-II, and 12-III respectively. Finally, the water in these three water tanks flows back to 12.

[0086] The compression heat pump unit receives hot water from water tank 12-Ⅲ via circulating water pump 9-Ⅵ into evaporator 13-Ⅰ, and the cooled water flows back into water tank 12-Ⅲ. The liquid in the compression heat pump exchanges heat with high-temperature water in evaporator 13-Ⅰ and then flows into compressor 17. The compressed gas flows into cooler 8-Ⅱ, and after cooler 8-Ⅱ cools the gas into liquid, it returns to evaporator 13-Ⅰ via throttling valve 18-Ⅰ.

[0087] In the absorption refrigeration unit, hot water from water tank 12-II flows into generator 14 via circulating water pump 9-Ⅳ, and the cooled water flows back into water tank 12-II. In the absorption refrigeration cycle, the refrigerant exchanges heat with the high-temperature water in generator 14 and then flows into condenser 8-Ⅲ. The refrigerant flowing out of condenser 8-Ⅲ flows into expansion valve 18-Ⅱ, and the refrigerant after passing through expansion valve 18-Ⅱ flows into evaporator 13-Ⅱ, thus forming a complete absorption refrigeration cycle process.

[0088] In the organic Rankine cycle power generation unit, hot water from water tank 12-I flows into heat exchanger 15 via circulating water pump 9-II, and the cooled water flows into water tank 12-I. The circulating agent on the organic Rankine cycle power generation side exchanges heat with high-temperature water in heat exchanger 15 and then flows into steam turbine 16. The circulating agent flowing out of steam turbine 16 flows into cooler 8-IV, and the circulating agent flows back into heat exchanger 15 via circulating water pump 9-III.

[0089] The energy self-sufficiency scheme of the water electrolysis hydrogen production plant of the present invention will be further explained below:

[0090] When the electrolyte in electrolyzer 1 of the hydrogen electrolysis unit is energized, it is electrolyzed to produce hydrogen and oxygen. Since the electrical energy cannot be fully used for the electrochemical reaction, some of the electrical energy will inevitably be converted into heat energy, causing the electrolyte temperature to rise. The gas-liquid mixture will then enter the gas-liquid separator 2. The high-temperature liquid flowing out after the gas-liquid separator 2 provides heat to the cascade heat storage tank. When the temperature controller 7 detects that the temperature at the outlet of the cascade heat storage tank exceeds 75°C, the cooler 8-I is activated to cool the electrolyte. This also indicates that the cascade heat storage tank has reached its maximum heat storage capacity and can be replaced with a new cascade heat storage tank for heat storage. When replacing the heat storage device, in order not to affect the normal operation of electrolyzer 1, the cooling required by the electrolyte is provided by the cooler 8-I. Subsequently, the replacement cascade heat storage tank is transported by a mobile energy storage vehicle to the required site to achieve the purpose of heating, cooling and power supply.

[0091] Hydrogen production plants need to compress low-pressure hydrogen into high-pressure hydrogen. During the compression process, a large amount of heat is generated. To utilize this heat, municipal water at around 20°C can be fed into heat exchanger 11 to cool the high-temperature hydrogen. The water coming out of heat exchanger 11 will reach around 35°C. Part of the water flowing out of heat exchanger 11 flows to cooling tower for circulation cooling, while the other part flows into water tank 12 to utilize this heat. The water flowing out of water tank 12 passes through a stepped heat storage tank, and the water temperature will rise further. This high-temperature water is then sent to the compression heat pump unit, absorption refrigeration unit, and organic Rankine cycle power generation unit to drive the normal operation of the units. The utilized high-temperature water will return to water tank 12, and this cycle will continue.

[0092] In the compression heat pump unit, the refrigerant absorbs heat and vaporizes into a high-temperature gas in the evaporator 13-I. This gas is then compressed into a high-temperature, high-pressure gas by the compressor 17, and the condenser 8-II supplies this heat to the heat user. In the absorption refrigeration unit, the refrigerant absorbs heat and vaporizes into a high-temperature gas in the generator 14. After passing through the condenser 8-III and the expansion valve 18-II, it transforms into a low-temperature, low-pressure liquid. This low-temperature, low-pressure liquid flows to the evaporator 13-II, which supplies this cooling capacity to the cold user. The liquid flowing out of the evaporator 13-II is absorbed by the absorber 19. The concentrated solution in the absorber 19 is sent to the generator 14 by the circulating pump 9-V, and the dilute solution in the generator 14 enters the absorber 19. This process is repeated to achieve a refrigeration cycle. In the organic Rankine cycle power generation unit, the refrigerant absorbs heat and vaporizes into a high-temperature gas in the heat exchanger 15. This high-temperature gas drives the steam turbine 16, which in turn drives the generator to provide power to the user.

[0093] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of the present invention.

Claims

1. A method for energy self-sufficiency in a water electrolysis hydrogen production plant, characterized in that, The energy self-sufficiency method of the water electrolysis hydrogen production plant includes: The high-temperature electrolyte in the electrolytic cell (1) flows to the gas-liquid separator (2) through the pipeline; The high-temperature electrolyte in the gas-liquid separator (2) flows to the cascade energy storage tank (6-Ⅱ); The cooled electrolyte flows to the electrolytic cell (1) via a circulation pump; Among them, the gas in the gas-liquid separator (2) flows into the gas diaphragm valve, and finally the gas flows through the gas diaphragm valve to the hydrogen purification device (4) and the oxygen post-treatment device (5) respectively; The first-stage heat storage tank (6-Ⅰ) is moved from the hydrogen production side of water electrolysis to the site where heat is required by a mobile energy storage vehicle (10).

2. The energy self-sufficiency method for a water electrolysis hydrogen production plant according to claim 1, characterized in that, The high-temperature hydrogen unit of the compressor station receives municipal water from the high-temperature hydrogen heat exchanger (11). Part of the water flowing out of the high-temperature hydrogen heat exchanger (11) flows to the cooling tower, and the other part flows to the first water tank (12). The water in the first water tank (12) flows into the second stage energy storage tank (6-II). The high-temperature water flowing out of the stage energy storage tank (6-II) flows to the second water tank (12-I), the third water tank (12-II), and the fourth water tank (12-III), respectively. Finally, the water flows back to the first water tank (12).

3. The energy self-sufficiency method for a water electrolysis hydrogen production plant according to claim 2, characterized in that, The compression heat pump unit circulates hot water from the fourth water tank (12-Ⅲ) through the fourth water pump (9-Ⅵ) into the second evaporator (13-Ⅰ), and the cooled water flows back into the fourth water tank (12-Ⅲ). The liquid in the compression heat pump exchanges heat with the high-temperature water in the second evaporator (13-Ⅰ) and then flows into the compressor (17). The compressed gas flows into the second cooler (8-Ⅱ), and after the second cooler (8-Ⅱ) cools the gas into liquid, it returns to the second evaporator (13-Ⅰ) through the second throttle valve (18-Ⅰ).

4. The energy self-sufficiency method for a water electrolysis hydrogen production plant according to claim 3, characterized in that, The absorption refrigeration unit receives hot water from the third water tank (12-II) via a circulating third water pump (9-Ⅳ) into the generator (14), and the cooled water flows back into the third water tank (12-II). The refrigerant in the absorption refrigeration cycle exchanges heat with the high-temperature water in the generator (14) and then flows into the cooler (8-Ⅲ). The refrigerant flowing out of the cooler (8-Ⅲ) flows into the second throttle valve (18-Ⅱ), and the refrigerant after passing through the second throttle valve (18-Ⅱ) flows into the first evaporator (13-Ⅱ), thus forming a complete absorption refrigeration cycle.

5. The energy self-sufficiency method for a water electrolysis hydrogen production plant according to claim 4, characterized in that, The organic Rankine cycle power generation unit receives hot water from the second water tank (12-I) via a first circulating water pump (9-II) into a heat exchanger (15), and the cooled water flows into the second water tank (12-I). The circulating agent on the organic Rankine cycle power generation side exchanges heat with the high-temperature water in the heat exchanger (15) and then flows into the steam turbine (16). The circulating agent flowing out of the steam turbine (16) flows into the first cooler (8-IV), and the circulating agent flows back into the heat exchanger (15) via a second circulating water pump (9-III).

6. The energy self-sufficiency method for a water electrolysis hydrogen production plant according to claim 5, characterized in that, When the electrolyte in the electrolytic cell (1) of the electrolytic hydrogen production unit is energized, it is electrolyzed to generate hydrogen and oxygen. Since the electricity cannot be fully used for the electrochemical reaction, the temperature of the electrolyte rises. The gas-liquid mixture will enter the gas-liquid separator (2). The high-temperature liquid flowing out after passing through the gas-liquid separator (2) provides heat to the cascade heat storage tank. When the temperature controller 7 detects that the temperature at the outlet of the cascade heat storage tank exceeds 75°C, the cooler (8-Ⅰ) is started to cool the electrolyte.

7. The energy self-sufficiency method for a water electrolysis hydrogen production plant according to claim 6, characterized in that, Hydrogen production plants need to compress low-pressure hydrogen into high-pressure hydrogen. During the compression process, a large amount of heat is generated. In order to utilize this heat, municipal water at around 20°C can be flowed into the heat exchanger (11) to cool the high-temperature hydrogen. The water coming out of the heat exchanger (11) will reach around 35°C. A portion of the water flowing out of the heat exchanger (11) will flow to the cooling tower to achieve the purpose of circulating cooling.

8. The energy self-sufficiency method for a water electrolysis hydrogen production plant according to claim 7, characterized in that, Another portion flows into the first water tank (12) to utilize this heat. The water flowing out of the first water tank (12) will have its temperature further increased after passing through the stepped heat storage tank. This high-temperature water will be sent to the compression heat pump unit, the absorption refrigeration unit and the organic Rankine cycle power generation unit to drive the normal operation of the unit. The high-temperature water that has been utilized will return to the first water tank (12) and repeat in this way.

9. The energy self-sufficiency method for a water electrolysis hydrogen production plant according to claim 8, characterized in that, In the compression heat pump unit, the circulating agent absorbs heat and vaporizes into high-temperature gas in the second evaporator (13-Ⅰ), which is then compressed into high-temperature and high-pressure gas by the compressor (17), and the second cooler (8-Ⅱ) supplies this heat to the heat user.

10. The energy self-sufficiency method for a water electrolysis hydrogen production plant according to claim 9, characterized in that, In the absorption refrigeration unit, the refrigerant absorbs heat and vaporizes into a high-temperature gas in the generator (14). After passing through the second cooler (8-Ⅲ) and the second throttle valve (18-Ⅱ), it is transformed into a low-temperature, low-pressure liquid. This low-temperature, low-pressure liquid flows to the first evaporator (13-Ⅱ), which supplies this cooling capacity to the users. The liquid flowing out of the first evaporator (13-Ⅱ) is absorbed by the absorber (19). The concentrated solution in the absorber (19) is sent into the generator (14) by the circulation pump 9-Ⅴ. The dilute solution in the generator (14) enters the absorber (19). This process is repeated to achieve a refrigeration cycle. In the organic Rankine cycle power generation, the circulating agent absorbs heat and vaporizes into a high-temperature gas in the heat exchanger (15). The high-temperature gas drives the steam turbine (16) to operate, and the steam turbine (16) drives the generator to operate, providing power to the users.

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