Seawater electrolysis hydrogen production system

Abstract

The utility model provides a seawater electrolysis hydrogen production system, and belongs to the technical field of seawater electrolysis hydrogen production. An existing membrane distillation method is low in water production rate and is difficult to match with the rate of hydrogen production by electrolysis of water; a reverse osmosis method is long in technological process and needs to be pressurized. The device comprises a forward osmosis module, an electrolyte transfer module, an electrolysis module and a gas-liquid separation module, ions in seawater are filtered through a forward osmosis device in the forward osmosis module, water is replenished to the electrolysis module, and the electrolysis speed and the water replenishing speed are balanced by establishing the balance between the electrolysis speed and the water replenishing speed; according to the invention, marine efficient water production and continuous seawater electrolysis hydrogen production can be realized, and additional pressurization except air is not needed in the forward osmosis process, so that the hydrogen production cost is saved.

Description

Technical Field

[0001] The utility model relates to the technical field of hydrogen production by electrolyzing seawater, and in particular to a hydrogen production system by electrolyzing seawater. Background Art

[0002] At present, the technical routes for hydrogen production by electrolysis of seawater are mainly divided into direct hydrogen production by electrolysis of seawater technology and indirect hydrogen production by electrolysis of seawater technology that first desalinates and desalinates the seawater.

[0003] Since there is Na in seawater + , Cl — , Ca 2+ Mg 2+ There are as many as 92 kinds of ions, among which chloride ions are very easy to corrode the electrode during the electrolysis process, and calcium and magnesium ions are very easy to precipitate and block the active sites at the local electrode reaction. Therefore, if the direct electrolysis of seawater to produce hydrogen technology is adopted, it is necessary to develop corrosion-resistant and non-scaling electrode materials. However, the current electrode materials and electrode structures cannot meet this requirement and are still in the experimental research stage.

[0004] Indirect electrolysis of seawater for hydrogen production technology. Currently, the commonly used methods for desalinating seawater mainly use membrane distillation and reverse osmosis. Among them, membrane distillation can use various forms of energy, has low requirements for the working environment, and is the method with the highest interception rate among the currently known seawater desalination methods. However, this method involves a gas-liquid phase change process, and the water production rate is low, which is difficult to match the rate of hydrogen production by electrolysis of water, and it still has problems such as membrane component pollution and low system energy recovery rate. The process technology route of seawater reverse osmosis desalination technology is mature, and the water production rate is fast, but the process flow is long, the energy consumption is high, and it needs to be pressurized, and the cost is high. It needs to be explained here that forward osmosis refers to placing the same volume of dilute solution (such as fresh water) and concentrated solution (such as seawater or salt water) on both sides of a container, with a semipermeable membrane in the middle to block it. The solvent water in the dilute solution will pass through the semipermeable membrane to the concentrated solution side. Reverse osmosis refers to the flow of water in seawater to the fresh water side. In order to achieve this purpose, it is necessary to use a pressurizing device such as a pressurized gas cylinder to apply a pressure greater than the osmotic pressure difference to the seawater side, so that the water in the seawater flows to the fresh water side. Therefore, the reverse osmosis method has higher requirements for pipelines and membrane elements. Utility Model Content

[0005] The technical problems to be solved by the utility model are:

[0006] In order to solve the problem that the existing membrane distillation method has a low water production rate and is difficult to match the rate of hydrogen production by water electrolysis; the reverse osmosis method has a long process flow and requires pressurization.

[0007] The utility model adopts the following technical solutions to solve the above technical problems:

[0008] The utility model provides a hydrogen production system by electrolyzing seawater, comprising a forward osmosis module, an electrolyte transfer module, an electrolysis module and a gas-liquid separation module.

[0009] The forward osmosis module includes a forward osmosis device, which includes a seawater holding component, an intermediate connecting component, an osmotic membrane fixing component and an electrolyte holding component in order from top to bottom. The seawater holding component is a round cover structure, and the seawater holding component is connected to seawater through a seawater circulation pump. The intermediate connecting component includes a tubular connecting component body, and a first truncated cone and a second truncated cone are provided on the outer wall of the connecting component body. A thread is provided on the outer wall of the lower end of the connecting component body, and the thread is located below the second truncated cone. The module also includes an osmotic membrane fixing component with an osmotic membrane at the center, and the osmotic membrane fixing component is a tubular structure and is sleeved on the outer wall of the lower end of the connecting component body through a thread. The seawater holding component is connected to the first truncated cone through a thread, and the electrolyte holding component is a barrel-shaped structure with an opening at the upper end, and the second truncated cone is connected to the electrolyte holding component through a thread. The electrolyte holding component is used to hold electrolyte, and the connecting component body with the osmotic membrane fixing component extends into the electrolyte holding component. When in use, the osmotic membrane is in contact with the electrolyte;

[0010] The electrolyte containing component is connected to the electrolyte transfer module, the electrolyte transfer module is connected to the electrolysis module, and the electrolysis module is connected to the gas-liquid separation module.

[0011] Furthermore, a coarse-mesh filter is provided below the permeable membrane.

[0012] Furthermore, the electrolyte containing component is connected to the electrolysis module via two peristaltic pumps to form electrolyte circulation.

[0013] Furthermore, the pressure in the electrolyte containing component is consistent with the pressure in the electrolyte transfer module.

[0014] Furthermore, the electrolyte transfer module is connected to the electrolytic cell in the electrolysis module via a peristaltic pump.

[0015] Furthermore, the gas-liquid separation module includes a hydrogen gas-liquid separation device, an oxygen gas-liquid separation device and a gas storage device, the electrolyzer is connected to the hydrogen gas-liquid separation device and the oxygen gas-liquid separation device, respectively, and the hydrogen gas-liquid separation device and the oxygen gas-liquid separation device are connected to the hydrogen storage tank and the oxygen storage tank in the gas storage device, respectively.

[0016] Furthermore, it also includes a temperature difference power generation module, which is used to supply power to the peristaltic pump, the seawater circulation pump, the hydrogen gas-liquid separation device and the oxygen gas-liquid separation device.

[0017] Furthermore, it also includes a wind power electric control module, and the wind power electric control module is connected to the electrolysis module.

[0018] Furthermore, the wind power electronic control module includes a control circuit board and an energy storage battery, which are both directly connected to the electrolyzer. When the remote terminal predicts that the wind force will increase according to the weather forecast, the information is fed back to the control circuit board through a wireless device, so as to increase the efficiency of electrolytic hydrogen production in advance, so as to maximize the wind power absorption and stabilize the system operation.

[0019] Furthermore, the first frustum is flush with the end of the connector body.

[0020] Compared with the prior art, the beneficial effects of the utility model are:

[0021] The utility model discloses a hydrogen production system by electrolyzing seawater, comprising a forward osmosis module, an electrolyte transfer module, an electrolysis module and a gas-liquid separation module. The water in the seawater is filtered by a forward osmosis device in the forward osmosis module and water is replenished to the electrolysis module. By establishing a balance between the electrolysis speed and the water replenishment speed, efficient water production at sea and continuous hydrogen production by electrolyzing seawater can be achieved. In addition, no additional pressurizing tank is required for pressurization except for air replenishment during the forward osmosis process. Under the action of gravity, the forward osmosis effect is further improved, and the hydrogen production cost is saved.

[0022] The utility model adopts an advanced scheduling method to achieve a balance between the two modules of wind power consumption and electrolytic hydrogen production, so that the deep-sea wind power hydrogen production system has high efficiency and stability; at the same time, the temperature difference between the electrolyzer and seawater is used to generate electricity and power the pump in the system, so as to achieve efficient use of energy and make the system green and recyclable. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a structural diagram of a system for producing hydrogen by electrolyzing seawater in an embodiment of the utility model;

[0024] Figure 2 It is a three-dimensional diagram of the forward osmosis device in the embodiment of the utility model;

[0025] Figure 3 It is an exploded view of the forward osmosis device in the embodiment of the utility model.

[0026] Description of reference numerals:

[0027] 1. Forward osmosis module; 2. Electrolyte transfer module; 3. Electrolysis module; 4. Hydrogen gas-liquid separation device; 5. Oxygen gas-liquid separation device; 6. Gas storage device; 7. Wind power electronic control module; 8. Temperature difference power generation module; 9. Seawater circulation pump; 110. Seawater holding component; 120. Intermediate connecting piece; 121. Connector body; 122. First truncated cone; 123. Second truncated cone; 124. Electrolyte connection hole; 130. Osmotic membrane fixing piece; 140. Osmotic membrane; 150. Electrolyte holding component; 160. Seawater connection hole. DETAILED DESCRIPTION

[0028] In the description of the present utility model, it should be noted that the terminology nouns in the various embodiments, such as words indicating directions such as "upper", "lower", "front", "back", "left", "right", etc., are only for simplifying the description of the positional relationship based on the drawings in the specification, and do not mean that the referred elements and devices must be operated according to the specific directions and specified operations and methods and structures in the specification. Such directional nouns do not constitute limitations on the present utility model.

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0030] Specific implementation plan 1: Combine Figures 1 to 3 As shown, the utility model provides a system for producing hydrogen by electrolyzing seawater, including a forward osmosis module 1, an electrolyte transfer module 2, an electrolysis module 3 and a gas-liquid separation module.

[0031] The forward osmosis module 1 includes a forward osmosis device, which includes a seawater holding component 110, an intermediate connecting component 120, an osmotic membrane fixing component 130 and an electrolyte holding component 150 from top to bottom. The seawater holding component 110 is a round cover structure. A seawater connecting hole 160 is provided on the seawater holding component 110, which is connected to seawater through a seawater circulation pump 9 and is used to introduce non-permeated seawater into the seawater holding component 110 and lead the permeated seawater out of the seawater holding component 110. The intermediate connecting component 120 includes a tubular connecting component body 121, and a first truncated cone 122 and a second truncated cone 123 are provided on the outer wall of the connecting component body 121. The first truncated cone 122 is flush with the end of the connecting component body 121. A thread is provided on the outer wall of the lower end of the connecting component body 121, and the thread is located below the second truncated cone 123. The connecting component body 121 also includes an osmotic membrane fixing component 130 with an osmotic membrane 140 at the center. The osmotic membrane fixing component 130 is a tubular structure and is connected to the connecting component body 121 through a thread. On the outer wall of the lower end of the connector body 121, the seawater holding component 110 is connected to the first truncated cone 122 by threads, the electrolyte holding component 150 is a barrel-shaped structure with an upper end opening, and the second truncated cone 123 is connected to the electrolyte holding component 150 by threads. The electrolyte holding component 150 is used to hold electrolyte. In the forward osmosis process, the electrolyte needs to contact the osmotic membrane 140 so that an osmotic pressure difference can be formed on both sides of the osmotic membrane 140. The part of the intermediate connector 120 connected to the osmotic membrane 140 penetrates into the electrolyte holding component 150 to ensure that there is liquid on both sides of the osmotic membrane 140; it is used to pump seawater into the seawater holding component 110 through the seawater circulation pump 9. Under the action of air pressurization and osmotic pressure difference, water molecules in the seawater pass through the osmotic membrane 140 and enter one side of the drawn liquid, where the drawn liquid is the electrolyte; the intermediate connector 120 can ensure good sealing in the forward osmosis device, so that the lower electrolyte level remains unchanged, and the water replenishment is more stable;

[0032] The forward osmosis device uses the forward osmosis method. The upper end is seawater, and the lower end is an electrolyte with a higher concentration than seawater. An osmotic pressure difference is formed between seawater and the electrolyte, forcing the water in the seawater to flow into the electrolyte. In addition, due to the electrolysis reaction on the electrolysis side, water is consumed, the concentration of the electrolyte increases, and the osmotic pressure difference becomes larger, which will further promote the water molecules in the seawater to move to the electrolyte side, achieving a "water replenishment" effect.

[0033] It should be explained that the pressurization in the forward osmosis device refers to the upper and lower structures. In addition to the osmotic pressure difference between the concentrated and dilute liquids, the liquid column with a certain height also provides further pressure, and there is a tendency to move downward under the action of gravity;

[0034] The electrolyte holding component 150 is connected to the electrolyte transfer module 2 through the electrolyte connection hole 124 opened on the second truncated cone 123, the electrolyte transfer module 2 is connected to the electrolysis module 3, and the electrolysis module 3 is connected to the gas-liquid separation module; it is used for the electrolyte to enter the electrolytic cell of the electrolysis module 3 for electrolysis after entering the electrolyte transfer module 2, and discharge the gas-liquid mixture after electrolysis through the exhaust pipes connected to the anode and cathode on the gas-liquid separation module for storage.

[0035] A coarse mesh filter is provided below the permeable membrane 140 to ensure the fixation of the working position of the permeable membrane 140; the bottom of the permeable membrane 140 is flush with the bottom of the permeable membrane fixing member 130. The permeable membrane 140 can be constructed with a forward osmosis CA membrane or other permeable membranes, which not only have a high ion retention rate, but also have considerable water flux. Among them, the forward osmosis CA membrane is a forward osmosis membrane commonly used in the prior art.

[0036] The electrolyte may be one or a combination of Na2SO4, NaH2PO3, and Na2HPO3 solutions.

[0037] Specific embodiment 2: Different from the specific embodiment 1, the electrolyte holding part 150 is connected to the electrolysis module 3 through two peristaltic pumps to form an electrolyte circulation, and the pressure in the electrolyte holding part 150 is consistent with the pressure of the electrolyte transfer module 2. In this way, a stable water replenishment rate and a higher water replenishment efficiency that can be adjusted by prefabricated air pressurization in the seawater holding part 110 are achieved.

[0038] Specific implementation scheme three: Different from specific implementation scheme two, the electrolyte transfer module 2 is connected to the electrolytic cell through a peristaltic pump, which is used to continuously provide electrolyte with stable concentration into the electrolytic cell. The forward osmosis device, the electrolyte transfer module 2 and the electrolyte in the electrolytic cell are continuously circulated through two sets of peristaltic pumps to ensure that the solution concentrations among the three form a dynamic balance and maintain a stable pressure difference to achieve stable electrolysis efficiency.

[0039] Specific implementation scheme 4: Different from specific implementation scheme 3, the gas-liquid separation module includes a hydrogen gas-liquid separation device 4, an oxygen gas-liquid separation device 5 and a gas storage device 6, and the electrolyzer is connected to the hydrogen gas-liquid separation device 4 and the oxygen gas-liquid separation device 5 respectively, and the hydrogen gas-liquid separation device 4 and the oxygen gas-liquid separation device 5 are respectively connected to the hydrogen storage tank and the oxygen storage tank in the gas storage device 6 for storing the separated hydrogen and oxygen. The separated electrolyte is transported back to the electrolyte transfer module 2 to realize the dynamic circulation of the absorption liquid and the electrolyte inside the device.

[0040] The gas-liquid separator uses gravity sedimentation separation. The liquid in the gas-liquid mixture entering the separator sinks to the bottom of the separator, and the gas enters the upper space to achieve gas-liquid separation. It is the same as the condensation principle and belongs to the commonly used gas-liquid separation technology in this field.

[0041] The electrolysis module 3 comprises a flow-type electrolyzer (PEM electrolyzer) consisting of a cathode, an anode and a proton exchange membrane, wherein the exchange membrane is used to prevent direct contact between the electrodes; the electrolyte is pumped or flows through the electrolyzer, usually by an external pump or natural convection; this continuous flow enables the electrolyte to continuously contact the anode and cathode, thereby promoting the electrolysis reaction;

[0042] At the anode, water molecules undergo an oxidation reaction: 2H2O(l)→O2(g)+4H+(aq)+4e-; in this process, water molecules are oxidized into oxygen and protons;

[0043] Protons pass through the proton exchange membrane and combine with electrons at the cathode to undergo a reduction reaction: 4H+(aq)+4e-→2H2(g); in this process, protons combine with electrons at the cathode to generate hydrogen;

[0044] The reaction equation of the entire PEM electrolyzer is: 2H2O(l)→2H2(g)+O2(g).

[0045] Specific implementation scheme five: Different from specific implementation scheme four, it also includes a temperature difference power generation module 8, which is used to power the peristaltic pump, the seawater circulation pump 9, the hydrogen gas-liquid separation device 4 and the oxygen gas-liquid separation device 5. Since the electrolyzer has an average temperature difference of about 40°C with the seawater during operation, based on the Seebeck effect, a temperature difference power generation module is set to generate electricity by using the temperature difference between the electrolyzer and the seawater during operation and to power the pumps and gas-liquid separation devices used in the system, which are relatively small in power, so as to improve the energy utilization rate of the electrolysis module 3, ensure the stability of the power supply of the electrolysis module 3 and the self-sustaining of the overall system. The temperature of the PEM electrolyzer is 50-80°C, and at least 30% of the energy is dissipated. The average temperature of the seawater is 20°C, so the temperature difference between the electrolyzer and the seawater is used to generate electricity and provide energy to the pumps in the entire system to maximize the utilization of energy.

[0046] The temperature difference power generation module 8 adopts the semiconductor temperature difference power generation chip SP1848-27145. When the temperature difference is 40 to 60°C, it can provide a voltage of 1.8V to 2.4V, and can be connected in series or in parallel to increase the voltage or current.

[0047] Specific implementation scheme six: Different from specific implementation scheme five, it also includes a wind power electric control module 7, and the wind power electric control module 7 is connected to the electrolysis module 3. Through electric control modulation and advance scheduling, the fluctuating power of wind power is converted into a stable current and input into the electrolyzer. Among them, the pulsed current can not only improve the efficiency and stability of hydrogen production, but also can be modulated in a wider range to achieve more efficient wind power consumption. The wind power electric control module 7 also includes a control circuit board and an energy storage battery, and both are connected to the electrolyzer. Based on weather forecasts, when the remote terminal predicts that the wind force will increase, the information is fed back to the control circuit board through a wireless device, and the efficiency of electrolytic hydrogen production is increased in advance, so as to maximize the wind power consumption and the stable operation of the system.

[0048] Furthermore, when the hydrogen production efficiency is controlled according to wind power, it is based on a wind power prediction model, which is a commonly used prediction model in the prior art. It can be understood that the overall system consists of three parts: a wind power control part, a battery energy storage part and electrolytic hydrogen production. Through the prediction model (in hours), for example, if it is predicted that the wind power in the next hour will be very strong, it will be fed back to the battery energy storage part, and the battery's SOC state of charge (that is, the battery's power) will be adjusted to increase the power output, thereby improving the hydrogen production efficiency, so that the SOC of the battery energy storage part is at a lower level, which is convenient for collecting a larger amount of wind power at the next moment, thereby improving the wind power absorption capacity. When it is predicted that the wind power is small, the transmission power of the battery energy storage part is small, which reduces the hydrogen production efficiency, while ensuring that the SOC of the battery energy storage part is always maintained within a certain range, so that its cycle life is longer.

[0049] The wind power electric control module 7 includes two-way isolation power supply modules, power overcurrent protection and surge protection modules, power backflow prevention modules, computing and Ethernet communication modules, 40-pin GPIO connectors, 4-way relay modules, RS-485 communication modules, and 8-way PWM output modules in the hardware part; in the software part, the product runs on Raspberry Pi OS, and all industrial control functions are implemented by the web server. The back end of the web server adopts the Web microframework Flask written in Python, and the front end adopts CSS; all of them are prior arts.

[0050] Although the utility model is disclosed as above, the protection scope of the utility model is not limited thereto. Those skilled in the art of the utility model may make various changes and modifications without departing from the spirit and scope of the utility model, and these changes and modifications will fall within the protection scope of the utility model.

[0051] Working principle: turn on the seawater circulation pump 9 and the two groups of peristaltic pumps, and the seawater is input into the seawater holding component 110 in the sealed forward osmosis device with the prefabricated air pressure on the upper side of the device through the seawater circulation pump 9. Under the combined effect of the osmotic pressure difference between the drawn liquid and the seawater and the prefabricated air in the seawater holding component 110, the water molecules in the seawater pass through the osmotic membrane 140 and enter the side of the drawn liquid. The liquid in the electrolyte transfer module 2 is connected to the electrolytic cell through the peristaltic pump and the delivery pipeline, and the electrolyte with a relatively stable concentration is continuously provided to the electrolytic cell. Under the power supply of the wind power control module 7 and the temperature difference power generation module 8, the electrolyte decomposes, and the decomposed gas and liquid are separated into hydrogen, oxygen and the decomposed electrolyte through the gas-liquid separation device. The hydrogen and oxygen are stored in the gas storage device 6. The electrolyte in the electrolytic cell forms a dynamic concentration balance with the forward osmosis device and the electrolyte transfer module 2 through the pumping of the two groups of peristaltic pumps, thereby realizing stable electrolysis.

Claims

1. A system for producing hydrogen by electrolyzing seawater, characterized in that: It comprises a forward osmosis module (1), an electrolyte transfer module (2), an electrolysis module (3) and a gas-liquid separation module. The forward osmosis module (1) comprises a forward osmosis device, which comprises, from top to bottom, a seawater holding component (110), an intermediate connecting component (120), an osmotic membrane fixing component (130) and an electrolyte holding component (150), wherein the seawater holding component (110) is a round cover structure, and the seawater holding component (110) is connected to seawater via a seawater circulation pump (9), and the intermediate connecting component (120) comprises a circular tubular connecting component body (121), and a first truncated cone (122) and a second truncated cone (123) are provided on the outer wall of the connecting component body (121), and a thread is provided on the outer wall of the lower end of the connecting component body (121), and the thread is located below the second truncated cone (123), and further comprises a center A permeable membrane fixing part (130) having a permeable membrane (140) is provided at the connector body (121), the permeable membrane fixing part (130) is a circular tubular structure and is threadedly sleeved on the outer wall of the lower end of the connector body (121), the seawater holding part (110) is threadedly connected to the first truncated cone (122), the electrolyte holding part (150) is a barrel-shaped structure with an upper end opening, the second truncated cone (123) is threadedly connected to the electrolyte holding part (150), the electrolyte holding part (150) is used to hold electrolyte, the connector body (121) with the permeable membrane fixing part (130) extends into the electrolyte holding part (150), and when in use, the permeable membrane (140) is in contact with the electrolyte; The electrolyte containing component (150) is connected to the electrolyte transfer module (2), the electrolyte transfer module (2) is connected to the electrolysis module (3), and the electrolysis module (3) is connected to the gas-liquid separation module.

2. A system for producing hydrogen by electrolysis of seawater according to claim 1, characterized in that: A coarse-mesh filter is provided below the permeable membrane (140).

3. A system for producing hydrogen by electrolysis of seawater according to claim 2, characterized in that: The electrolyte containing component (150) is connected to the electrolysis module (3) via two peristaltic pumps to form electrolyte circulation.

4. A system for producing hydrogen by electrolysis of seawater according to claim 3, characterized in that: The pressure inside the electrolyte containing component (150) is consistent with the pressure of the electrolyte transfer module (2).

5. A system for producing hydrogen by electrolysis of seawater according to claim 3, characterized in that: The electrolyte transfer module (2) is connected to the electrolytic cell in the electrolysis module (3) via a peristaltic pump.

6. A system for producing hydrogen by electrolysis of seawater according to claim 5, characterized in that: The gas-liquid separation module comprises a hydrogen gas-liquid separation device (4), an oxygen gas-liquid separation device (5) and a gas storage device (6); the electrolyzer is connected to the hydrogen gas-liquid separation device (4) and the oxygen gas-liquid separation device (5), respectively; the hydrogen gas-liquid separation device (4) and the oxygen gas-liquid separation device (5) are connected to a hydrogen storage tank and an oxygen storage tank in the gas storage device (6), respectively.

7. A system for producing hydrogen by electrolysis of seawater according to claim 6, characterized in that: It also comprises a temperature difference power generation module (8), wherein the temperature difference power generation module (8) is used to supply power to a peristaltic pump, a seawater circulation pump (9), a hydrogen gas-liquid separation device (4) and an oxygen gas-liquid separation device (5).

8. A system for producing hydrogen by electrolyzing seawater according to claim 7, characterized in that: It also includes a wind power electric control module (7), and the wind power electric control module (7) is connected to the electrolysis module (3).

9. A system for producing hydrogen by electrolysis of seawater according to claim 8, characterized in that: The wind power electric control module (7) comprises a control circuit board and an energy storage battery, both of which are directly connected to the electrolyzer, and are used to feed back information to the control circuit board through a wireless device when the remote terminal predicts that the wind force will increase according to the weather forecast, so as to increase the efficiency of electrolytic hydrogen production in advance, so as to achieve maximum wind power absorption and stable operation of the system.

10. A system for producing hydrogen by electrolyzing seawater according to claim 9, characterized in that: The first truncated cone (122) is flush with the end of the connecting member body (121).

Images