A controllable low-energy-consuming lye generation device and control method for hydrogen production from seawater

Abstract

The present invention discloses a controllable low-energy-consuming lye generation device and control method for hydrogen production from seawater. The device includes: a cylindrical metal inner tank, which contains lye inside, and has a second interface at the bottom, and is connected to a lye electrolytic cell through a lye circulation pipeline; a semi-region of the inner tank side wall is attached with a selective permeable membrane, which sucks pure water into the inner tank by using the osmotic pressure difference between the lye and the external seawater to achieve seawater desalination; a liquid level sensor is installed at the top of the inner tank, and the lye concentration is calculated by detecting the liquid level height; a rotary outer shell is sleeved outside the inner tank, and the contact area between the selective permeable membrane and the seawater is adjusted by its own rotation, so as to adjust the seawater desalination rate; wherein the rotation of the rotary outer shell is controlled by a power and transmission mechanism. The present invention allows users to dynamically adjust the seawater desalination rate according to the water consumption rate of the electrolytic hydrogen production equipment, maintain the lye in the electrolytic hydrogen production equipment at the concentration with the optimal conductivity, and realize the improvement of the efficiency of the seawater hydrogen production equipment.

Description

Technical Field

[0001] The present invention belongs to the technical field of seawater direct electrolysis for hydrogen production in the new energy field, and particularly relates to a controllable low-energy-consuming lye generation device and a control method for seawater hydrogen production. Background Art

[0002] The basic principle of electrolytic hydrogen production is that under the action of direct current in an electrolytic cell, water is decomposed into hydrogen (H 2 ) and oxygen (O 2 ). Specifically, a voltage is applied between the cathode and anode of the electrolytic cell, causing water electrolysis to produce hydrogen and oxygen. Hydrogen is evolved at the cathode and oxygen is evolved at the anode.

[0003] Electrolytic hydrogen production using an alkaline solution electrolytic cell has significant advantages compared to other electrolytic hydrogen production methods (such as proton exchange membrane electrolysis and solid oxide electrolysis, etc.). First, the cost of the alkaline solution electrolytic cell is relatively low, the equipment structure is relatively simple, and it is easy to maintain. Second, the operating temperature of the alkaline solution electrolytic cell is relatively low, generally between 70°C and 80°C, which means that more economical materials can be used to manufacture the equipment, reducing the overall cost. In addition, the alkaline solution electrolytic cell is also relatively flexible in operation and can adjust the current density according to requirements to regulate the hydrogen production rate.

[0004] However, electrolytic hydrogen production using an alkaline solution electrolytic cell has limitations in the field of seawater hydrogen production. The salt content in seawater will affect the concentration of the alkaline solution in the electrolytic cell, thereby affecting the electrolysis efficiency. In addition, the salt content in seawater may also cause scaling inside the electrolytic cell, further reducing the electrolysis efficiency and increasing the maintenance cost. Existing seawater desalination methods mostly use thermal or reverse osmosis technologies, which are energy-consuming and not easy to integrate into the electrolytic hydrogen production system. Therefore, it is particularly important to develop a device that can efficiently and energy-savingly extract fresh water from seawater and can automatically adjust the lye concentration during the electrolytic hydrogen production process. Summary of the Invention

[0005] The purpose of the present invention is to provide a controllable low-energy-consuming lye generation device and a control method for seawater hydrogen production in view of the deficiencies of the prior art. The present invention solves the problem of unstable lye concentration caused by different water consumption when the seawater hydrogen production equipment operates at different powers, and improves the overall operating efficiency of the seawater hydrogen production equipment.

[0006] The purpose of the present invention is achieved through the following technical solutions: In the first aspect of the embodiments of the present invention, a controllable low-energy-consuming lye generation device for seawater hydrogen production is provided, including:

[0007] A cylindrical metal inner container, with an overall shape of a hollow cylinder, contains alkali solution inside; half of the side wall of the cylindrical metal inner container adopts a hollow grid structure, a first interface and a transmission installation part are arranged at the top of the cylindrical metal inner container, and two second interfaces are arranged at the bottom of the cylindrical metal inner container;

[0008] A selective permeable membrane is attached to the surface of the hollow grid structure;

[0009] A rotary outer shell, with an overall shape of a hollow semi-cylinder, is sleeved outside the cylindrical metal inner container;

[0010] A liquid level sensor is installed at the first interface;

[0011] Two alkali solution circulation pipelines, one end of which is connected to the second interface, and the other end is communicated with the alkali solution electrolysis tank of the electrolytic hydrogen production equipment; and

[0012] A power and transmission mechanism is installed on the transmission installation part, and the power and transmission mechanism is used to control and drive the rotary outer shell to rotate.

[0013] Further, the cylindrical metal inner container is made of a corrosion-resistant material, and the alkali solution contained inside is a concentrated potassium hydroxide solution with a mass percentage concentration of 30%.

[0014] Further, the selective permeable membrane is made of a hydrophobic porous polytetrafluoroethylene-based membrane and is used as a gaseous water exchange channel. The external seawater and the alkali solution in the cylindrical metal inner container are separated by a hydrophobic porous polytetrafluoroethylene-based membrane. The transmembrane water vapor pressure difference between the external seawater and the alkali solution in the cylindrical metal inner container is used to drive the transfer of water molecules, so that the seawater spontaneously vaporizes, and the water vapor freely diffuses through the selective permeable membrane into the cylindrical metal inner container and re-liquefies, supplementing the water consumed by the electrolytic hydrogen production equipment and realizing the regeneration of the alkali solution in the cylindrical metal inner container.

[0015] Further, the rotary outer shell is made of a corrosion-resistant material, and the rotary outer shell is driven to rotate by the power and transmission mechanism to change the effective exchange and migration area of the alkali solution in the cylindrical metal inner container and the external seawater through the selective permeable membrane, so as to control the regeneration speed of the alkali solution in the cylindrical metal inner container.

[0016] Further, the liquid level sensor measures and records the liquid level height of the alkali solution in the cylindrical metal inner container at the current moment in real time by adopting the ultrasonic ranging principle, and outputs a corresponding 4-20mA analog electrical signal for the control of the power and transmission mechanism.

[0017] Further, the diameters of the two alkali solution circulation pipelines are the same; the alkali solution circulation pipelines are made of materials that are resistant to strong alkali corrosion inside and seawater corrosion outside.

[0018] Furthermore, the power and transmission mechanism adopts a combined structure of an inverter and a stepper motor. The processor in the inverter samples the 4 - 20 mA analog electrical signal output by the liquid level sensor, and controls the inverter to drive the stepper motor to drive the rotary outer shell to rotate according to the change in the liquid level height of the alkali solution in the cylindrical metal inner tank at the current moment.

[0019] Furthermore, the control method of the stepper motor specifically includes:

[0020] By rotating forward or backward by a specified angle θ, driving the rotary outer shell to rotate by the specified angle θ, so as to change the contact area between the selective permeable membrane and the external seawater, control the speed of pure water in the seawater permeating into the cylindrical metal inner tank, and realize the control of the concentration of the alkali solution in the cylindrical metal inner tank; the control law of this stepper motor is expressed as:

[0021] ;

[0022] wherein, the value range of θ is [0, π], k p is the proportional coefficient, k i is the integral coefficient, s is the Laplace operator, and Δh is the change in the liquid level height of the alkali solution.

[0023] The second aspect of the embodiment of the present invention provides a control method for the above - mentioned controllable low - energy - consumption alkali solution generating device for hydrogen production from seawater, including the following steps:

[0024] (1) Use the liquid level sensor to measure the liquid level height h of the alkali solution in the cylindrical metal inner tank at the current moment k ;

[0025] (2) Subtract the liquid level height value h k measured at the previous moment from the liquid level height h at the current moment k-1 , to obtain the change in liquid level height Δh;

[0026] (3) Input the change in liquid level height Δh into the PI controller, and calculate the rotation angle θ of the stepper motor in the power and transmission mechanism according to the control law of the stepper motor;

[0027] (4) The inverter in the power and transmission mechanism drives the stepper motor to rotate by the specified angle θ according to the above calculation result, and the stepper motor drives the rotary outer shell to rotate by the specified angle θ, so as to adjust the effective exchange and migration area on both sides of the selective permeable membrane and control the regeneration speed of the alkali solution in the cylindrical metal inner tank.

[0028] The beneficial effects of the present invention are as follows: The present invention designs a controllable passive lye regeneration device for seawater hydrogen production equipment. By changing the contact area between the hydrophobic porous polytetrafluoroethylene-based membrane attached to the surface of the device and seawater, the rate of gaseous water migration from seawater into the controllable passive lye regeneration device is controlled, thereby achieving the control of the lye concentration in the seawater hydrogen production equipment, enabling the lye to maintain the concentration corresponding to good conductivity, and further improving the seawater hydrogen production efficiency; by adding the device of the present invention to the seawater hydrogen production equipment, not only is there no additional energy consumption, but also the existing mature electrolytic hydrogen production equipment can be directly used in the field of seawater hydrogen production, which not only improves the working efficiency of the seawater hydrogen production equipment itself, but also reduces the waste of resources for the re-research of equipment in the field of seawater hydrogen production; the present invention allows users to dynamically adjust the rate of seawater desalination according to the water consumption rate of the electrolytic hydrogen production equipment, maintain the lye in the electrolytic hydrogen production equipment at the concentration with the optimal conductivity, and achieve the improvement of the efficiency of the seawater hydrogen production equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of the controllable low-energy consumption lye generation device for seawater hydrogen production of the present invention;

[0030] Figure 2 It is a schematic control flow diagram of the controllable low-energy consumption lye generation device for seawater hydrogen production of the present invention.

[0031] In the figure, cylindrical metal inner tank 1, hollow grid structure 11, first interface 12, transmission installation part 13, second interface 14, selective permeable membrane 2, rotary outer shell 3. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present invention as detailed in the appended claims.

[0033] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "the", and "said" used in the present invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0034] It should be understood that although the terms first, second, third, etc. may be used in the present invention to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of the present invention, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to a determination".

[0035] The present invention will be described in detail below with reference to the accompanying drawings. Without conflict, the features in the following embodiments and implementation manners may be combined with each other.

[0036] The controllable low-energy-consuming lye generation device for seawater hydrogen production of the present invention can achieve passive lye regeneration without energy consumption, as Figure 1 shown, specifically including a cylindrical metal inner tank 1, a selective permeable membrane 2, a rotary outer shell 3, a liquid level sensor, two lye circulation pipes, and a power and transmission mechanism. Among them, the overall shape of the cylindrical metal inner tank 1 is a hollow cylinder, and lye is contained therein; half of the side wall of the cylindrical metal inner tank 1 adopts a hollow grid structure 11, the top of the cylindrical metal inner tank 1 is provided with a first interface 12 and a transmission installation part 13, and the bottom of the cylindrical metal inner tank 1 is provided with two second interfaces 14. The selective permeable membrane 2 is attached to the surface of the hollow grid structure 11. The overall shape of the rotary outer shell 3 is a hollow semi-cylinder, which is sleeved outside the cylindrical metal inner tank 1. The liquid level sensor is installed at the first interface 12. The whole device is directly immersed in seawater, and the lye circulation pipe is connected to the electrolytic hydrogen production equipment, that is, one end of the lye circulation pipe is connected to the second interface 14, and the other end is connected to the lye electrolysis tank of the electrolytic hydrogen production equipment. The power and transmission mechanism is installed on the transmission installation part 13, and the power and transmission mechanism is used to control and drive the rotary outer shell 3 to rotate.

[0037] Furthermore, the cylindrical metal inner tank 1 is made of a corrosion-resistant material, and the lye contained therein is a concentrated potassium hydroxide solution with a mass percentage concentration of 30%.

[0038] Furthermore, the selective permeable membrane 2 is made of a hydrophobic porous polytetrafluoroethylene-based membrane and is used as a gaseous water exchange channel. The external seawater and the lye in the cylindrical metal inner tank 1 are separated by the hydrophobic porous polytetrafluoroethylene-based membrane. The transmembrane water vapor pressure difference between the external seawater and the lye in the cylindrical metal inner tank 1 is used to drive the transfer of water molecules, so that seawater spontaneously vaporizes, and water vapor freely diffuses through the selective permeable membrane 2 into the cylindrical metal inner tank 1 and re-liquefies, replenishing the water consumed by the electrolytic hydrogen production equipment, thereby realizing the regeneration of the lye in the cylindrical metal inner tank 1.

[0039] Further, the rotary outer shell 3 is made of corrosion-resistant material and is driven to rotate by a power and transmission mechanism, so as to change the effective exchange and migration area of the lye in the cylindrical metal inner container 1 and the external seawater through the selective permeable membrane 2, thereby realizing the control of the regeneration speed of the lye in the cylindrical metal inner container 1.

[0040] Further, the liquid level sensor is a high-precision liquid level sensor, which adopts the ultrasonic ranging principle to measure and record the liquid level height of the lye in the cylindrical metal inner container 1 at the current moment in real time, and outputs a corresponding 4-20 mA analog electrical signal for the control of the power and transmission mechanism.

[0041] Further, the two lye circulation pipes have the same diameter; the lye circulation pipes are made of materials that are resistant to strong alkali corrosion inside and seawater corrosion outside.

[0042] Further, the power and transmission mechanism adopts a combined structure of an inverter and a stepping motor. The processor in the inverter samples the 4-20 mA analog electrical signal output by the liquid level sensor, and controls the inverter to drive the stepping motor to drive the rotary outer shell 3 to rotate a certain angle θ according to the change amount Δh of the liquid level height of the lye in the cylindrical metal inner container 1 at the current moment.

[0043] Further, the control method of the stepping motor specifically includes: driving the rotary outer shell 3 to rotate a specified angle θ by rotating forward or backward by a specified angle θ to change the contact area between the selective permeable membrane 2 and the external seawater, controlling the speed of pure water in the seawater to penetrate into the cylindrical metal inner container 1, and realizing the control of the lye concentration in the cylindrical metal inner container 1; correspondingly, the control law of the stepping motor is expressed as:

[0044]

[0045] wherein, the value range of θ is [0, π], k p is the proportional coefficient, k i is the integral coefficient, s is the Laplace operator, and Δh is the change amount of the liquid level height of the lye.

[0046] It is worth mentioning that the embodiment of the present invention also provides a control method for the controllable low-energy-consuming lye generating device for hydrogen production from seawater described in the above embodiment, as Figure 2 shown, which specifically includes the following steps:

[0047] (1) Measuring the liquid level height h of the lye in the cylindrical metal inner container 1 at the current moment by using the liquid level sensor k .

[0048] (2) Subtracting the liquid level height value h k measured at the previous moment from the liquid level height h k-1, the change in liquid level height Δh is obtained.

[0049] (3) Input the change in liquid level height Δh into the PI controller, and calculate the rotation angle θ of the stepper motor in the power and transmission mechanism according to the control law of the stepper motor.

[0050] (4) The inverter in the power and transmission mechanism drives the stepper motor to rotate by a specified angle θ according to the above calculation results. The stepper motor drives the rotary housing 3 to rotate by a specified angle θ to adjust the effective exchange and migration area on both sides of the selective permeable membrane 2, and control the regeneration rate of the lye in the cylindrical metal inner tank 1.

[0051] In summary, the present invention controls the rate of gaseous water migration in seawater into the controllable passive lye regeneration device by changing the contact area between the hydrophobic porous polytetrafluoroethylene-based membrane attached to the surface of the device, thereby realizing the controllability of the lye concentration in the seawater hydrogen production equipment, enabling the lye to maintain the concentration corresponding to good conductivity, and further improving the seawater hydrogen production efficiency; the present invention allows users to dynamically adjust the seawater desalination rate according to the water consumption rate of the electrolytic hydrogen production equipment, maintain the lye in the electrolytic hydrogen production equipment at the concentration with the optimal conductivity, and realize the improvement of the efficiency of the seawater hydrogen production equipment.

[0052] 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 foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A controllable low-energy alkali solution production device for seawater hydrogen production, characterized in that: include: A cylindrical metal liner (1) is in the form of a hollow cylinder, and contains alkali solution; half of the side wall of the cylindrical metal liner (1) adopts a hollow grid structure (11); the top of the cylindrical metal liner (1) is provided with a first interface (12) and a transmission mounting portion (13); and the bottom of the cylindrical metal liner (1) is provided with two second interfaces (14); A selectively permeable membrane (2) is attached to the surface of the hollow grid structure (11); The rotating outer shell (3) is in the shape of a hollow semi-cylinder and is sleeved on the outside of the cylindrical metal liner (1); A liquid level sensor installed at the first interface (12); two alkali solution circulation pipes, one end of which is connected to the second interface (14), and the other end of which is connected to the alkali solution electrolytic cell of the electrolytic hydrogen production equipment; and A power and transmission mechanism is mounted on the transmission mounting portion (13), and the power and transmission mechanism is used to control and drive the rotating housing (3) to rotate; The liquid level sensor uses the ultrasonic distance measurement principle to measure and record the liquid level of the alkali solution in the cylindrical metal liner (1) at the current moment in real time, and outputs a corresponding 4-20mA analog electrical signal for controlling the power and transmission mechanism; The power and transmission mechanism adopts a combined structure of an inverter and a stepper motor. The processor in the inverter samples the 4-20mA analog signal output by the liquid level sensor, and controls the inverter to drive the stepper motor to drive the rotating housing (3) to rotate according to the change in the liquid level of the alkali solution in the cylindrical metal liner (1) at the current moment. The control method of the stepper motor specifically includes: By rotating the rotating housing (3) at a specified angle θ in a forward or reverse direction, the rotating housing (3) is driven to rotate at a specified angle θ, thereby changing the contact area between the selective permeable membrane (2) and the external seawater, controlling the speed at which pure water in the seawater penetrates into the cylindrical metal inner liner (1), and realizing control of the concentration of the alkali solution in the cylindrical metal inner liner (1); the control law of the stepper motor is expressed as: Among them, the value range of θ is [0,π], k p is the proportionality coefficient, k i is the integral coefficient, s is the Laplace operator, and Δh is the change in the liquid level of the alkali solution.

2. The controllable low-energy alkali solution generating device for producing hydrogen from seawater according to claim 1, characterized in that: The cylindrical metal inner container (1) is made of corrosion-resistant material, and the alkali solution contained therein is a concentrated potassium hydroxide solution with a mass percentage concentration of 30%.

3. The controllable low-energy alkali solution generating device for producing hydrogen from seawater according to claim 1, characterized in that: The selective permeable membrane (2) is made of a hydrophobic porous polytetrafluoroethylene-based membrane and is used as a gaseous water exchange channel. The external seawater and the alkaline solution in the cylindrical metal inner liner (1) are separated by a hydrophobic porous polytetrafluoroethylene-based membrane. The transmembrane water vapor pressure difference between the external seawater and the alkaline solution in the cylindrical metal inner liner (1) is used to drive the transfer of water molecules, so that the seawater is spontaneously vaporized. The water vapor freely diffuses into the cylindrical metal inner liner (1) through the selective permeable membrane (2) and is reliquefied, thereby replenishing the water consumed by the electrolytic hydrogen production equipment and realizing the regeneration of the alkaline solution in the cylindrical metal inner liner (1).

4. The controllable low-energy alkali solution generating device for producing hydrogen from seawater according to claim 1, characterized in that: The rotating outer shell (3) is made of corrosion-resistant material and is driven to rotate by a power and transmission mechanism to change the effective exchange migration area between the alkali solution in the cylindrical metal liner (1) and the external seawater through the selective permeability diaphragm (2), thereby achieving control of the regeneration speed of the alkali solution in the cylindrical metal liner (1).

5. The controllable low-energy alkali solution generating device for producing hydrogen from seawater according to claim 1, characterized in that: The two alkali solution circulation pipelines have the same diameter; the alkali solution circulation pipelines are made of a material that is resistant to strong alkali corrosion on the inside and resistant to seawater corrosion on the outside.

6. A control method for a controllable low-energy alkali solution generating device for producing hydrogen from seawater according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Using a liquid level sensor to measure the liquid level h of the alkali solution in the cylindrical metal liner (1) at the current moment k ; (2) The current liquid level h k Subtract the liquid level value h measured at the last moment k-1 , and obtain the liquid level height change Δh; (3) The liquid level height change Δh is input into the PI controller, and the rotation angle θ of the stepper motor in the power and transmission mechanism is calculated according to the control law of the stepper motor; (4) The inverter in the power and transmission mechanism drives the stepper motor to rotate a specified angle θ according to the above calculation results, and the stepper motor drives the rotating housing (3) to rotate a specified angle θ to adjust the effective exchange migration area on both sides of the selective permeable membrane (2) and control the regeneration speed of the alkali solution in the cylindrical metal liner (1).

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