Anion exchange membrane water electrolysis hydrogen production system and method based on seawater

Abstract

The invention discloses a seawater-based anion exchange membrane water electrolysis hydrogen production system which comprises an anion exchange membrane electrolytic bath unit, a hydrogen gravity type separation unit, a hydrogen washing unit, a hydrogen purification unit, an oxygen gravity type separation unit, an oxygen washing unit, an oxygen-liquid separation unit, a weak alkali liquid circulation unit, a heat exchange unit, a flash evaporation unit and a seawater desalination unit, a vacuum pump unit, a seawater filtering lightering unit and a fresh water storage and supply unit. Fresh water circulation between the flash evaporation unit and the heat exchange unit can be carried out, repeated utilization of fresh water is achieved, hot weak alkali liquid needing to be cooled can be used for heating circulating fresh water, then flash evaporation is carried out on hot fresh water, generated steam serves as a heat source to heat seawater of the seawater desalination unit, low-temperature desalination is carried out on the seawater in a negative pressure environment, and the seawater desalination efficiency is improved. The prepared fresh water can be used as raw material fresh water of the anion exchange membrane electrolytic cell unit.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen production by electrolysis, and in particular, to a system and method for producing hydrogen by electrolyzing water using an anion exchange membrane based on seawater. Background Art

[0002] Hydrogen is a new energy source with zero carbon emissions and is considered an ideal fuel for addressing environmental and energy issues. Using green electricity to electrolyze water to produce hydrogen can achieve the goal of zero carbon emissions. Anion exchange membrane water electrolysis technology combines the advantages of traditional alkaline water electrolysis and proton exchange membrane (PEM) water electrolysis. It avoids the large-scale use of precious metals in the alkaline system, and the equipment cost is greatly reduced compared to PEM water electrolysis. It is a very promising hydrogen production technology.

[0003] With the large-scale development of wind power generation, randomness and volatility are no longer the main problems that restrict its grid connection. The lagging grid construction can no longer meet the rapid expansion of wind power development. In order to promote the consumption of new energy and optimize the energy structure, the development of supporting energy storage facilities is conducive to the efficient use of wind resources. Hydrogen production from offshore wind power has the advantages of huge available wind resources, no land occupation, and abundant seawater resources, making it the best choice for the development of hydrogen energy.

[0004] Therefore, how to develop an anion exchange membrane water electrolysis hydrogen production system and method based on seawater, which can not only use offshore wind power to produce hydrogen, but also produce fresh water to meet the raw fresh water demand for anion exchange membrane water electrolysis hydrogen production, help meet the application needs of distributed offshore wind power hydrogen production scenarios, and also improve the utilization efficiency of offshore wind power, has great strategic significance. Summary of the invention

[0005] According to the technical problems mentioned in the above background technology, a system and method for producing hydrogen by electrolysis of water using an anion exchange membrane based on seawater is provided. The present invention provides a system and method for producing hydrogen by electrolysis of water using an anion exchange membrane based on seawater, which can heat circulating fresh water using hot weak alkaline solution that needs to be cooled, and then flash evaporate the hot fresh water. The generated steam is used as a heat source to heat the seawater in the seawater desalination unit. The seawater is desalinated at low temperature under a negative pressure environment. The prepared fresh water can be used as raw fresh water for the anion exchange membrane electrolyzer unit, which can be applied to distributed offshore wind power hydrogen production scenarios, in order to provide technical support for the development of equipment for producing hydrogen by electrolysis of water using anion exchange membrane based on seawater that is technologically independent and controllable.

[0006] The technical means adopted by the present invention are as follows:

[0007] A hydrogen production system based on seawater anion exchange membrane water electrolysis, comprising:

[0008] Anion exchange membrane electrolyzer unit, hydrogen gravity separation unit, hydrogen purification unit, oxygen gravity separation unit, oxygen liquid separation unit, weak alkaline liquid circulation unit, heat exchange unit, flash unit, seawater desalination unit, vacuum pump unit, seawater filtration and transfer unit, fresh water storage and supply unit;

[0009] The offshore green electricity drives the anion exchange membrane electrolyzer unit to decompose fresh water into hydrogen and oxygen; hydrogen and weak alkaline liquid pass through the hydrogen gravity separation unit to achieve gas-liquid separation; oxygen and weak alkaline liquid pass through the oxygen gravity separation unit to achieve gas-liquid separation; the hot alkaline liquid of the hydrogen gravity separation unit and the oxygen gravity separation unit is cooled by the fresh water in the heat exchange unit, and then the weak alkaline liquid circulation unit provides circulation power to the anion exchange membrane electrolyzer unit; the fresh water in the heat exchange unit is heated by the hot weak alkaline liquid and enters the flash evaporation unit, and the generated water vapor enters the seawater desalination unit as a heat source for heating seawater; after heating, the seawater is distilled and desalinated under a vacuum environment, and the seawater is provided by the seawater filtration and barge unit, and the generated fresh water is stored in the seawater storage and supply unit; the flash evaporation unit and the heat exchange unit circulate fresh water;

[0010] Hydrogen and a small amount of water enter the hydrogen purification unit, where they are deoxygenated and dried to achieve high purity and low dew point of hydrogen, which is then supplied to users.

[0011] Furthermore, the present invention also includes a method for producing hydrogen by electrolyzing water using an anion exchange membrane based on seawater, comprising the following steps:

[0012] Step 1: offshore green electricity drives the anion exchange membrane electrolyzer unit to decompose fresh water into hydrogen and oxygen;

[0013] Step 2: hydrogen and weak alkaline solution are separated by passing through the hydrogen gravity separation unit; oxygen and weak alkaline solution are separated by passing through the oxygen gravity separation unit;

[0014] Step 3: The hot alkali liquid of the hydrogen gravity separation unit and the oxygen gravity separation unit is cooled by the fresh water in the heat exchange unit and then provided with circulation power by the weak alkali liquid circulation unit to the anion exchange membrane electrolyzer unit;

[0015] Step 4: the fresh water in the heat exchange unit is heated by the hot weak alkaline solution and then enters the flash unit, and the generated water vapor enters the seawater desalination unit as a heat source for heating seawater;

[0016] Step 5: The heated seawater is distilled and desalinated under a vacuum environment. The seawater is provided by a seawater filtration and transfer unit, and the generated fresh water is stored in a seawater storage and supply unit;

[0017] Step 6: The flash unit and the heat exchange unit perform fresh water circulation;

[0018] Step 7: Hydrogen and a small amount of water enter the hydrogen purification unit, where they are deoxygenated and dried to achieve high purity and low dew point of hydrogen, which is then supplied to users.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] The present invention can circulate fresh water between the flash unit and the heat exchange unit to achieve the repeated use of fresh water, and can use the hot weak alkali solution that needs to be cooled to heat the circulating fresh water, and then flash the hot fresh water, and the generated steam is used as a heat source to heat the seawater of the seawater desalination unit, and the seawater is desalinated at low temperature under a negative pressure environment. The prepared fresh water can be used as raw fresh water for the anion exchange membrane electrolyzer unit. Therefore, the present invention can not only improve the utilization rate of thermal energy and increase the water production ratio, but also be applicable to the distributed offshore wind power hydrogen production scenario, which is conducive to promoting the rapid development of offshore wind power hydrogen production. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0022] Figure 1 It is the main function flow chart of the present invention.

[0023] Figure 2 It is a process system flow chart of an implementation case of the present invention.

[0024] In the figure: 1 is the baseline, 2 is the anion exchange membrane electrolyzer unit, 3 is the hydrogen gravity separation unit, 4 is the hydrogen washing unit, 5 is the hydrogen purification unit, 6 is the oxygen gravity separation unit, 7 is the oxygen washing unit, 8 is the oxygen liquid separation unit, 9 is the weak alkali liquid circulation unit, 10 is the heat exchange unit, 11 is the flash unit, 12 is the seawater desalination unit, 13 is the vacuum pump unit, 14 is the seawater filtration and barge unit, 15 is the fresh water storage and supply unit, 21 is the anion exchange membrane electrolyzer, 31 is the hydrogen horizontal gravity separator, 41 is the hydrogen washing tower, 51 is the hydrogen purification module, 61 is the oxygen horizontal gravity separator, 71 is Oxygen washing tower, 81 is an oxygen liquid separator, 91 is a weak alkali liquid circulation pump, 92 is a weak alkali liquid filter, 101 is a heat exchanger, 102 is a fresh water circulation pump, 103 is a pressure reducing valve, 111 is a flash evaporator, 112 is a vacuum instrument, 113 is a remote control valve, 121 is a seawater desalination device, 122 is a temperature meter, 123 is a remote control valve, 124 is a salinity meter, 125 is a remote control valve, 126 is a flow meter, 131 is a vacuum pump, 132 is a vacuum instrument, 141 is a seawater pump, 142 is a multi-media filter, 143 is an activated carbon filter, 144 is a precision filter, 151 is a fresh water storage tank, and 152 is a fresh water supply pump. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0026] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0027] The present invention Figure 1It is a main functional flow chart of a system and method for producing hydrogen by electrolysis of water using an anion exchange membrane based on seawater, wherein baseline 1 is a system and method for producing hydrogen by electrolysis of water using an anion exchange membrane based on seawater; the functional realization units of the system and method for producing hydrogen by electrolysis of water using an anion exchange membrane based on seawater of the present invention mainly include: an anion exchange membrane electrolyzer unit 2, a hydrogen gravity separation unit 3, a hydrogen washing unit 4, a hydrogen purification unit 5, an oxygen gravity separation unit 6, an oxygen washing unit 7, an oxygen liquid separation unit 8, a weak alkaline liquid circulation unit 9, a heat exchange unit 10, a flash unit 11, a seawater desalination unit 12, a vacuum pump unit 13, a seawater filtration and transportation unit 14, and a fresh water storage and supply unit 15.

[0028] As a preferred embodiment, in the present application, the power interface of the anion exchange membrane electrolyzer unit 1 is connected to green electricity such as offshore wind power; the hydrogen outlet of the anion exchange membrane electrolyzer unit 1 is connected to the hydrogen gravity separation unit 3; the oxygen outlet of the anion exchange membrane electrolyzer unit 1 is connected to the oxygen gravity separation unit 6; the low-temperature weak alkaline liquid inlet of the anion exchange membrane electrolyzer unit is connected to the outlet of the weak alkaline liquid circulation unit. The fresh water in the anion exchange membrane electrolyzer unit is decomposed into hydrogen and oxygen under the action of green electricity such as offshore wind power, and the hydrogen and hot weak alkaline liquid enter the hydrogen gravity separation unit, and the oxygen and hot weak alkaline liquid enter the oxygen gravity separation unit.

[0029] The hydrogen inlet of the hydrogen gravity separation unit 2 is connected to the hydrogen outlet of the anion exchange membrane electrolyzer unit; the hydrogen outlet of the hydrogen gravity separation unit is connected to the hydrogen inlet of the hydrogen washing unit; the hot weak alkaline liquid outlet of the hydrogen gravity separation unit is connected to the heat exchange unit; the weak alkaline liquid reflux port of the hydrogen gravity separation unit is connected to the weak alkaline liquid outlet of the hydrogen washing unit.

[0030] The hydrogen inlet of the hydrogen washing unit 3 is connected to the hydrogen outlet of the hydrogen gravity separation unit; the hydrogen outlet of the hydrogen washing unit is connected to the hydrogen purification unit; the fresh water inlet of the hydrogen washing unit is connected to the fresh water storage and supply unit; the weak alkali liquid outlet of the hydrogen washing unit is connected to the weak alkali liquid reflux port of the hydrogen gravity separation unit. Main functions: washing the weak alkali in hydrogen, cooling the hydrogen, and replenishing fresh water raw materials to the anion exchange membrane electrolyzer unit.

[0031] The inlet of the hydrogen purification unit 4 is connected to the hydrogen washing unit; the outlet of the hydrogen purification unit can be connected to a hydrogen user or storage device to remove trace oxygen in the hydrogen and reduce the moisture content of the hydrogen, so that the outlet hydrogen reaches high purity and low dew point hydrogen.

[0032] The oxygen inlet of the oxygen gravity separation unit 5 is connected to the oxygen outlet of the anion exchange membrane electrolyzer unit; the oxygen outlet of the oxygen gravity separation unit is connected to the oxygen inlet of the oxygen washing unit; the hot weak alkali liquid outlet of the oxygen gravity separation unit is connected to the heat exchange unit, and the weak alkali liquid reflux port of the oxygen gravity separation unit is connected to the weak alkali liquid outlet of the oxygen washing unit. Oxygen and alkali liquid are separated, and fresh water raw material can be added to the anion exchange membrane electrolyzer unit.

[0033] The oxygen inlet of the oxygen washing unit 6 is connected to the oxygen outlet of the oxygen gravity separation unit; the oxygen outlet of the oxygen washing unit is connected to the oxygen liquid separation unit; the fresh water inlet of the oxygen washing unit is connected to the fresh water storage supply unit; the weak alkaline liquid outlet of the oxygen washing unit is connected to the weak alkaline liquid reflux port of the oxygen gravity separation unit. Main functions: washing the weak alkali in the oxygen and cooling the hydrogen.

[0034] The oxygen inlet of the oxygen-liquid separation unit 7 is connected to the oxygen outlet of the oxygen washing unit; the oxygen outlet of the oxygen-liquid separation unit is discharged to a safe area. Main functions: realize gas-liquid separation of oxygen and improve oxygen purity.

[0035] The inlet of the weak alkali liquid circulation unit 8 is connected to the weak alkali liquid outlet of the heat exchange unit; the outlet of the weak alkali liquid circulation unit is connected to the low-temperature weak alkali liquid inlet of the anion exchange membrane electrolyzer unit. Mainly realized function: providing power for weak alkali liquid circulation.

[0036] The weak alkali liquid inlet of the heat exchange unit 9 is connected to the hot weak alkali liquid outlet of the hydrogen gravity separation unit and the oxygen gravity separation unit respectively; the low-temperature weak alkali liquid outlet of the heat exchange unit is connected to the inlet of the weak alkali liquid circulation unit; the fresh water inlet of the heat exchange unit is connected to the circulating water outlet of the flash unit and the circulating fresh water outlet of the seawater desalination unit respectively; the hot fresh water outlet of the heat exchange unit is connected to the fresh water inlet of the flash unit. Main functions: Cool the hot weak alkali liquid with fresh water and increase the fresh water temperature for flash evaporation treatment.

[0037] The fresh water inlet of the flash unit 10 is connected to the hot fresh water outlet of the heat exchange unit; the vacuum outlet of the flash unit is connected to the vacuum pump unit; the circulating water outlet of the flash unit is connected to the fresh water inlet of the heat exchange unit; the steam outlet of the flash unit is connected to the seawater desalination unit. The main functions are: flash evaporation of the fresh water heated by the heat exchange unit, and transporting the steam as a heat source to the seawater desalination unit.

[0038] The steam inlet of the desalination unit 11 is connected to the steam outlet of the flash unit; the circulating fresh water outlet of the desalination unit is connected to the fresh water inlet of the heat exchange unit; the vacuum outlet of the desalination unit is connected to the vacuum pump unit; the seawater inlet of the desalination unit is connected to the seawater filtration and transfer unit; the fresh water outlet of the desalination unit is connected to the fresh water storage and supply unit. Main functions: In a negative pressure environment, steam is used as a heat source to heat seawater to achieve low-temperature seawater desalination.

[0039] The inlet of the vacuum pump unit 12 is connected to the vacuum outlet of the flash evaporation unit and the seawater desalination unit respectively; the outlet of the vacuum pump unit is led to a safe area for evacuation. The main function is to provide a vacuum environment for the flash evaporation unit and the seawater desalination unit.

[0040] The seawater inlet of the seawater filtration and transportation unit 13 is led to the seawater source; the outlet of the seawater filtration and transportation unit is connected to the seawater desalination unit. The main functions are: pre-treating the seawater and providing seawater for the seawater desalination unit.

[0041] The fresh water inlet of the fresh water storage and supply unit 14 is connected to the seawater desalination unit; the outlet of the fresh water storage and supply unit is respectively connected to the fresh water inlet and external output of the hydrogen washing unit and the oxygen washing unit. The main functions are: storing fresh water prepared by seawater desalination, providing washing water for the washing unit, and replenishing fresh water raw materials for the anion exchange membrane electrolyzer unit. Extra fresh water can be supplied externally.

[0042] As a preferred method, a method for producing hydrogen by electrolyzing water using an anion exchange membrane based on seawater comprises the following steps: offshore green electricity drives an anion exchange membrane electrolyzer unit 2 to decompose fresh water into hydrogen and oxygen; hydrogen and weak alkaline solution pass through a hydrogen gravity separation unit 3 to achieve gas-liquid separation, and then hydrogen and a small amount of alkaline solution enter a hydrogen washing unit 4 to further remove the alkaline solution, wherein the alkaline solution of the hydrogen washing unit 4 can flow back to the hydrogen gravity separation unit 3, and finally hydrogen and a small amount of water enter a hydrogen purification unit 5, and high purity and low dew point of hydrogen are achieved through deoxygenation and drying, and then the hydrogen is supplied to users; in addition, oxygen and weak alkaline solution pass through an oxygen gravity separation unit 6 to achieve gas-liquid separation, and then oxygen and a small amount of alkaline solution enter an oxygen washing unit 7 to further remove the alkaline solution, wherein the alkaline solution of the oxygen washing unit 7 can flow back to the oxygen gravity separation unit 6, and finally oxygen and a small amount of water enter an oxygen liquid separation unit 8, thereby obtaining oxygen with higher purity, and then Lead to a safe area for emptying; the hot alkali liquid of the hydrogen gravity separation unit 3 and the oxygen gravity separation unit 6 is cooled by the fresh water in the heat exchange unit 10, and the weak alkali liquid circulation unit 9 provides circulation power to the anion exchange membrane electrolyzer unit 2; the fresh water in the heat exchange unit 10 is heated by the hot weak alkali liquid and enters the flash evaporation unit 11, and the generated water vapor enters the seawater desalination unit 12 as a heat source for heating seawater, and the vacuum degree of the flash evaporation unit 11 and the seawater desalination unit 12 is maintained by the vacuum pump unit 13. After heating, the seawater is distilled and desalinated under a vacuum environment, and the seawater is provided by the seawater filtration and transportation unit 14. The generated fresh water is stored in the seawater storage and supply unit 15, and the raw fresh water can be supplemented to the anion exchange membrane electrolyzer unit 2 through the hydrogen washing unit 4 and the oxygen washing unit 7; the flash evaporation unit 11 and the heat exchange unit 10 circulate fresh water, and can be supplemented by fresh water from seawater desalination, so as to realize the repeated use of fresh water.

[0043] Figure 2This is a process system flow chart of an implementation case of the present invention. As can be seen from the figure, the anion exchange membrane electrolyzer 21 realizes the use of green electricity to electrolyze water to produce hydrogen and oxygen; the hydrogen horizontal gravity separator 31 realizes the gas-liquid separation of hydrogen and alkali liquid; the hydrogen washing tower 41 realizes the washing of a small amount of alkali liquid in hydrogen, and can replenish fresh water to the anion exchange membrane electrolyzer 21; the hydrogen purification module 51 realizes high purity and low dew point of hydrogen through deoxygenation, drying, etc.; the oxygen horizontal gravity separator 61 realizes the gas-liquid separation of oxygen and alkali liquid; the oxygen washing tower 71 realizes the washing of a small amount of alkali liquid in oxygen, and can replenish fresh water to the anion exchange membrane electrolyzer 21; the oxygen liquid separator 81 realizes the gas-liquid separation of hydrogen and water, and improves the purity of oxygen. ; The weak alkali liquid circulation unit 9 is composed of a weak alkali liquid circulation pump 9 and a weak alkali liquid filter 92, which provide power for the alkali liquid circulation and filter impurities; the heat exchange unit 10 is composed of a heat exchanger 101, a fresh water circulation pump 102, and a pressure reducing valve 103. The heat exchanger 101 realizes heat exchange between hot weak alkali liquid and fresh water, the fresh water circulation pump 102 provides power for the fresh water circulation, and the pressure reducing valve 103 enhances the flash evaporation of fresh water; the flash evaporation unit 11 is composed of a flash evaporator 111, a vacuum instrument 112, and a remote control valve 113. The flash evaporator 111 is used to flash fresh water to generate steam, and the vacuum instrument 112 adjusts the flow rate by controlling the opening of the remote control valve 113 to ensure the vacuum degree requirement of the flash evaporator 111; the desalination unit 12 is composed of a sea The desalination device 121, a temperature meter 122, a remote control valve 123, a salinity meter 124, a remote control valve 125, and a flow meter 126 are composed of the seawater desalination device 121 for realizing negative pressure low-temperature desalination of seawater. The temperature meter 122 controls the opening of the remote control valve 123 based on the seawater temperature signal in the seawater desalination device 121 to adjust the amount of seawater entering. The salinity meter 124 controls the opening and closing of the remote control valve 125 based on the seawater concentration in the seawater desalination device 121 to discharge concentrated seawater in time. The flow meter 126 is used to measure the amount of fresh water generated; the vacuum pump unit 13 is composed of a vacuum pump 131 and a vacuum meter 132. The vacuum meter 132 controls the vacuum pump by sending a vacuum degree signal in the seawater desalination device 121. 131 operating power, in order to control the vacuum degree within a reasonable range; the seawater filtration and transfer unit 14 is composed of a seawater pump 141, a multi-media filter 142, an activated carbon filter 143, and a precision filter 144. The seawater pump 141 provides seawater for the seawater desalination unit, and the multi-media filter 142, the activated carbon filter 143, and the precision filter 144 mainly pre-treat the seawater; the fresh water storage and supply unit 15 is composed of a fresh water storage tank 151 and a fresh water supply pump 152. The fresh water storage tank 151 stores the fresh water prepared by seawater desalination, and the fresh water supply pump 152 delivers washing water to the washing unit, and can replenish fresh water raw materials for the anion exchange membrane electrolyzer unit.

[0044] The present invention can circulate fresh water between the flash unit and the heat exchange unit to achieve the repeated use of fresh water, and can use the hot weak alkali solution that needs to be cooled to heat the circulating fresh water, and then flash the hot fresh water, and the generated steam is used as a heat source to heat the seawater of the seawater desalination unit, and the seawater is desalinated at low temperature under a negative pressure environment. The prepared fresh water can be used as raw fresh water for the anion exchange membrane electrolyzer unit. Therefore, the present invention can not only improve the utilization rate of thermal energy and increase the water production ratio, but also be applicable to the distributed offshore wind power hydrogen production scenario, which is conducive to promoting the rapid development of offshore wind power hydrogen production.

[0045] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages and disadvantages of the embodiments. In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments. In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hydrogen production system based on seawater anion exchange membrane water electrolysis, characterized in that: include: Anion exchange membrane electrolyzer unit (2), hydrogen gravity separation unit (3), hydrogen purification unit (5), oxygen gravity separation unit (6), oxygen liquid separation unit (8), weak alkaline liquid circulation unit (9), heat exchange unit (10), flash unit (11), seawater desalination unit (12), vacuum pump unit (13), seawater filtration and transfer unit (14), fresh water storage and supply unit (15); The offshore green electricity drives the anion exchange membrane electrolyzer unit (2) to decompose fresh water into hydrogen and oxygen; hydrogen and weak alkaline liquid pass through the hydrogen gravity separation unit (3) to achieve gas-liquid separation; oxygen and weak alkaline liquid pass through the oxygen gravity separation unit (6) to achieve gas-liquid separation; the hot alkaline liquid of the hydrogen gravity separation unit (3) and the oxygen gravity separation unit (6) is cooled by the fresh water in the heat exchange unit (10), and then the weak alkaline liquid circulation unit (9) provides circulation power to the anion exchange membrane electrolyzer unit (2); the fresh water in the heat exchange unit (10) is heated by the hot weak alkaline liquid and enters the flash evaporation unit (11), and the generated water vapor enters the seawater desalination unit (12) as a heat source for heating seawater; after heating, the seawater is distilled and desalinated under a vacuum environment, the seawater is provided by the seawater filtration and transportation unit (14), and the generated fresh water is stored in the seawater storage and supply unit (15); the flash evaporation unit (11) and the heat exchange unit (10) circulate fresh water; Hydrogen and a small amount of water enter the hydrogen purification unit (5) and are deoxygenated and dried to achieve high purity and low dew point of hydrogen, which is then supplied to users.

2. A seawater-based anion exchange membrane water electrolysis hydrogen production system according to claim 1, characterized in that: The system also has a hydrogen washing unit (4); the hydrogen after gas-liquid separation enters the hydrogen washing unit (4) to remove the alkali liquid.

3. The anion exchange membrane water electrolysis hydrogen production system based on seawater according to claim 1, characterized in that: The system also has an oxygen washing unit (7); oxygen after gas-liquid separation enters the oxygen washing unit (7) to remove alkali liquid.

4. A hydrogen production system based on seawater anion exchange membrane water electrolysis according to claim 2, characterized in that: The alkaline solution in the hydrogen washing unit (4) can flow back to the hydrogen gravity separation unit (3); at the same time, the raw fresh water of the anion exchange membrane electrolyzer unit (2) is supplemented through the hydrogen washing unit (4).

5. The anion exchange membrane water electrolysis hydrogen production system based on seawater according to claim 3, characterized in that: The alkaline solution in the oxygen washing unit (7) can flow back to the oxygen gravity separation unit (6); at the same time, the raw fresh water of the anion exchange membrane electrolyzer unit (2) is supplemented through the oxygen washing unit (7).

6. The anion exchange membrane water electrolysis hydrogen production system based on seawater according to claim 1, characterized in that: The system also has an oxygen-liquid separation unit (8); oxygen and a small amount of water enter the oxygen-liquid separation unit (8) to obtain oxygen with higher purity, which is then led to a safe area for discharge.

7. The anion exchange membrane water electrolysis hydrogen production system based on seawater according to claim 1, characterized in that: The system also has a vacuum pump unit (13); the vacuum pump unit (13) maintains the vacuum degree of the flash evaporation unit (11) and the seawater desalination unit (12).

8. A method for producing hydrogen by electrolyzing water using anion exchange membrane based on seawater, characterized in that: The following steps are involved: Step 1: offshore green electricity drives the anion exchange membrane electrolyzer unit to decompose fresh water into hydrogen and oxygen; Step 2: hydrogen and weak alkaline solution are separated by passing through the hydrogen gravity separation unit; oxygen and weak alkaline solution are separated by passing through the oxygen gravity separation unit; Step 3: The hot alkali liquid of the hydrogen gravity separation unit and the oxygen gravity separation unit is cooled by the fresh water in the heat exchange unit and then provided with circulation power by the weak alkali liquid circulation unit to the anion exchange membrane electrolyzer unit; Step 4: the fresh water in the heat exchange unit is heated by the hot weak alkaline solution and then enters the flash unit, and the generated water vapor enters the seawater desalination unit as a heat source for heating seawater; Step 5: The heated seawater is distilled and desalinated under a vacuum environment. The seawater is provided by a seawater filtration and transfer unit, and the generated fresh water is stored in a seawater storage and supply unit; Step 6: The flash unit and the heat exchange unit perform fresh water circulation; Step 7: Hydrogen and a small amount of water enter the hydrogen purification unit, where they are deoxygenated and dried to achieve high purity and low dew point of hydrogen, which is then supplied to users.

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