Controllable low-energy-consumption alkali liquor generation device for seawater hydrogen production and control method

Abstract

The invention discloses a controllable low-energy-consumption alkali liquor generating device for seawater hydrogen production and a control method, and the device comprises a cylindrical metal liner which is internally provided with alkali liquor, is provided with a second interface at the bottom, and is communicated with an alkali liquor electrolytic bath through an alkali liquor circulating pipeline; a selective permeable diaphragm is attached to a half area of the side wall of the inner container, and pure water is sucked into the inner container by utilizing the osmotic pressure difference between alkali liquor and external seawater, so that seawater desalination is realized; a liquid level sensor is mounted at the top of the liner, and the alkali liquor concentration is calculated by detecting the liquid level height; the rotary shell is arranged outside the inner container in a sleeving manner, and the contact area between the selective permeable diaphragm and seawater is adjusted through self rotation, so that the seawater desalination rate is adjusted; wherein the rotation of the rotary housing is controlled by a power and transmission mechanism. According to the invention, a user is allowed to dynamically adjust the seawater desalination rate according to the water consumption rate of the electrolytic hydrogen production equipment, the alkali liquor in the electrolytic hydrogen production equipment is maintained at the concentration with the optimal electric conductivity, and the efficiency of the seawater hydrogen production equipment is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of direct hydrogen production by electrolysis of seawater in the field of new energy, and in particular relates to a controllable low-energy alkali solution production device and a control method for producing hydrogen from seawater. Background Art

[0002] The basic principle of hydrogen production by electrolysis is to decompose water into hydrogen (H2) and oxygen (O2) through the action of direct current in an electrolyzer. Specifically, a voltage is applied between the cathode and anode of the electrolyzer to electrolyze water to produce hydrogen and oxygen, with hydrogen being precipitated at the cathode and oxygen being precipitated at the anode.

[0003] Compared with other methods of hydrogen production by electrolysis (such as proton exchange membrane electrolysis and solid oxide electrolysis), alkaline solution electrolyzers have significant advantages. First, the cost of alkaline solution electrolyzers is low, the equipment structure is relatively simple, and it is easy to maintain. Secondly, the operating temperature of alkaline solution electrolyzers 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, alkaline solution electrolyzers are relatively flexible in operation, and the current density can be adjusted according to demand to adjust the hydrogen production rate.

[0004] However, hydrogen production by electrolysis in alkaline solution electrolyzers has limitations in the field of hydrogen production from seawater. The salt in seawater will affect the concentration of alkaline solution in the electrolyzer, which in turn affects the electrolysis efficiency. In addition, the salt in seawater may also cause scaling inside the electrolyzer, further reducing the electrolysis efficiency and increasing maintenance costs. Existing seawater desalination methods mostly use thermal or reverse osmosis technology, which has high energy consumption and is not easy to integrate into electrolytic hydrogen production systems. Therefore, it is particularly important to develop a device that can extract fresh water from seawater efficiently and energy-savingly, and can automatically adjust the concentration of alkaline solution during the electrolytic hydrogen production process. Summary of the invention

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

[0006] The objective of the present invention is achieved through the following technical solutions: In a first aspect, an embodiment of the present invention provides a controllable low-energy alkali solution production device for producing hydrogen from seawater, comprising: The cylindrical metal liner is in the shape of a hollow cylinder, and contains alkali solution; half of the side wall of the cylindrical metal liner adopts a hollow grid structure, the top of the cylindrical metal liner is provided with a first interface and a transmission mounting part, and the bottom of the cylindrical metal liner is provided with two second interfaces; A selectively permeable membrane is attached to the surface of the hollow grid structure; The rotating shell is in the shape of a hollow semi-cylinder and is sleeved on the outside of the cylindrical metal liner; A liquid level sensor, installed at the first interface; two alkali solution circulation pipes, one end of which is connected to the second interface and the other end of which is connected to the alkali solution electrolyzer of the electrolytic hydrogen production equipment; and A power and transmission mechanism is installed on the transmission installation portion, and the power and transmission mechanism is used to control and drive the rotating shell to rotate.

[0007] Furthermore, the cylindrical metal inner container 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%.

[0008] Furthermore, 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 alkaline solution in the cylindrical metal inner liner 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 is used to drive the transfer of water molecules, so that the seawater is spontaneously vaporized, and the water vapor freely diffuses into the cylindrical metal inner liner through the selective permeable membrane and reliquefies, 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.

[0009] Furthermore, the rotating shell 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 and the external seawater through the selective permeability membrane, thereby achieving control of the regeneration speed of the alkali solution in the cylindrical metal liner.

[0010] Furthermore, the liquid level sensor adopts the ultrasonic distance measurement principle to measure and record the liquid level height of the alkali solution in the cylindrical metal liner at the current moment in real time, and outputs a corresponding 4-20mA analog electrical signal for controlling the power and transmission mechanism.

[0011] Furthermore, the diameters of the two alkali solution circulation pipes are the same; the alkali solution circulation pipes are made of a material that is resistant to strong alkali corrosion on the inside and resistant to seawater corrosion on the outside.

[0012] Furthermore, the power and transmission mechanism adopts a combined structure of an inverter and a stepper motor. The processor in the inverter samples the 4-20mA analog signal output by the liquid level sensor, and controls the inverter to drive the stepper motor to drive the rotating 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.

[0013] Furthermore, the control method of the stepper motor specifically includes: By rotating the rotating housing at a specified angle θ in the forward or reverse direction, the contact area between the selective permeable membrane and the external seawater is changed, the speed at which the pure water in the seawater penetrates into the cylindrical metal liner is controlled, and the concentration of the alkali solution in the cylindrical metal liner is controlled; 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.

[0014] A second aspect of an embodiment of the present invention provides a control method for the above-mentioned controllable low-energy alkali solution production device for producing hydrogen from seawater, comprising the following steps: (1) Use the liquid level sensor to measure the liquid level h of the alkali solution in the cylindrical metal liner 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. The stepper motor drives the rotating housing to rotate a specified angle θ to adjust the effective exchange migration area on both sides of the selective permeable membrane and control the regeneration speed of the alkali solution in the cylindrical metal liner.

[0015] The beneficial effects of the present invention are as follows: the present invention designs a controllable passive alkali solution regeneration device for the seawater hydrogen production equipment, and controls the rate at which gaseous water in the seawater migrates into the controllable passive alkali solution regeneration device by changing the contact area between the hydrophobic porous polytetrafluoroethylene-based membrane attached to the surface of the device and the seawater, thereby achieving controllable alkali solution concentration in the seawater hydrogen production equipment, so that the alkali solution can be maintained at a concentration corresponding to a good conductivity, thereby improving the efficiency of hydrogen production from seawater; by adding the device described in the present invention to the seawater hydrogen production equipment, not only is there no additional energy consumption, but 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-development of equipment in the field of seawater hydrogen production; the present invention allows the user to dynamically adjust the rate of seawater desalination according to the water consumption rate of the electrolytic hydrogen production equipment, maintain the alkali solution in the electrolytic hydrogen production equipment at a concentration with the optimal conductivity, and achieve the improvement of the efficiency of the seawater hydrogen production equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of a controllable low-energy alkali solution production device for producing hydrogen from seawater according to the present invention; Figure 2 The figure is a control flow diagram of the controllable low-energy alkali solution production device for producing hydrogen from seawater according to the present invention.

[0017] In the figure, there is a cylindrical metal liner 1, a hollow grid structure 11, a first interface 12, a transmission mounting portion 13, a second interface 14, a selectively permeable membrane 2, and a rotatable housing 3. DETAILED DESCRIPTION

[0018] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the present invention as detailed in the appended claims.

[0019] 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 "the" used in the present invention and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. 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 associated listed items.

[0020] It should be understood that although the terms first, second, third, etc. may be used in the present invention to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information 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 "at the time of" or "when" or "in response to determining".

[0021] The present invention is described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the features of the following embodiments and implementations can be combined with each other.

[0022] The controllable low-energy alkali solution generation device for hydrogen production from seawater of the present invention can realize passive alkali solution regeneration without energy consumption, such as Figure 1As shown, it specifically includes a cylindrical metal liner 1, a selective permeable membrane 2, a rotating shell 3, a liquid level sensor, two alkali solution circulation pipelines and a power and transmission mechanism. Among them, the overall shape of the cylindrical metal liner 1 is a hollow cylinder, and alkali solution is contained inside; 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. The selective permeable membrane 2 is attached to the surface of the hollow grid structure 11. The overall shape of the rotating shell 3 is a hollow semi-cylinder, which is sleeved on the outside of the cylindrical metal liner 1. The liquid level sensor is installed at the first interface 12. The device as a whole is directly immersed in seawater, and the alkali solution circulation pipeline is connected to the electrolytic hydrogen production equipment, that is, one end of the alkali solution circulation pipeline is connected to the second interface 14, and the other end is connected to the alkali solution electrolyzer of the electrolytic hydrogen production equipment. The power and transmission mechanism is installed on the transmission installation portion 13 , and is used to control and drive the rotating housing 3 to rotate.

[0023] Furthermore, the cylindrical metal inner liner 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%.

[0024] 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 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, and the water vapor freely diffuses into the cylindrical metal inner liner 1 through the selective permeable membrane 2 and reliquefies, replenishing the water consumed by the electrolytic hydrogen production equipment, thereby realizing the regeneration of the alkaline solution in the cylindrical metal inner liner 1.

[0025] Furthermore, the rotating 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 permeable membrane 2, thereby achieving control of the regeneration speed of the alkali solution in the cylindrical metal liner 1.

[0026] Furthermore, the liquid level sensor is a high-precision liquid level sensor, which adopts 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 output a corresponding 4-20mA analog electrical signal for the control of the power and transmission mechanism.

[0027] Furthermore, the diameters of the two alkali solution circulation pipes are the same; the alkali solution circulation pipes are made of a material that is resistant to strong alkali corrosion on the inside and resistant to seawater corrosion on the outside.

[0028] Furthermore, the power and transmission mechanism adopts a combined structure of an inverter and a stepper motor. The processor in the inverter samples the 4-20mA 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 a certain angle θ according to the liquid level change Δh of the alkali solution in the cylindrical metal liner 1 at the current moment.

[0029] Furthermore, the control method of the stepper motor specifically includes: by rotating the specified angle θ in the forward or reverse direction, the rotating housing 3 is driven to rotate the specified angle θ, so as to change the contact area between the selective permeable membrane 2 and the external seawater, control the speed at which the pure water in the seawater penetrates into the cylindrical metal liner 1, and realize the control of the alkali solution concentration in the cylindrical metal liner 1; correspondingly, the control law of the stepper motor is expressed as:

[0030] 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.

[0031] It is worth mentioning that the embodiment of the present invention also provides a control method for the controllable low-energy alkali solution generating device for producing hydrogen from seawater as described in the above embodiment, such as Figure 2 As shown, the specific steps include:

[0032] (1) Use the liquid level sensor to measure the liquid level h of the alkali solution in the cylindrical metal liner 1 at the current moment k .

[0033] (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 change Δh.

[0034] (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.

[0035] (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. 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 alkaline solution in the cylindrical metal liner 1.

[0036] In summary, the present invention controls the rate at which gaseous water in seawater migrates into the controllable passive alkali solution regeneration device by changing the contact area between the hydrophobic porous polytetrafluoroethylene-based membrane attached to the surface of the device and seawater, thereby achieving controllable alkali solution concentration in the seawater hydrogen production device, so that the alkali solution can be maintained at a concentration corresponding to good conductivity, thereby improving the seawater hydrogen production efficiency; the present invention allows the user to dynamically adjust the seawater desalination rate according to the water consumption rate of the electrolytic hydrogen production device, maintain the alkali solution in the electrolytic hydrogen production device at a concentration with optimal conductivity, and achieve improved efficiency of the seawater hydrogen production device.

[0037] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions 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, containing alkali solution; half of the side wall of the cylindrical metal liner (1) adopts a hollow grid structure (11); a first interface (12) and a transmission mounting portion (13) are provided at the top of the cylindrical metal liner (1); and two second interfaces (14) are provided at the bottom of the cylindrical metal liner (1); A selectively permeable membrane (2) attached to the surface of the hollow grid structure (11); The rotating outer shell (3) is in the form 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.

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 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 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 liner (1) through the selective permeable membrane (2) and is re-liquefied, thereby replenishing the water consumed by the electrolytic hydrogen production equipment and achieving the regeneration of the alkaline solution in the cylindrical metal 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 housing (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 membrane (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 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.

6. 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.

7. The controllable low-energy alkali solution generating device for producing hydrogen from seawater according to claim 1, characterized in that: 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.

8. The controllable low-energy alkali solution generating device for producing hydrogen from seawater according to claim 7, characterized in that: 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 liner (1), and realizing control of the concentration of the alkali solution in the cylindrical metal 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.

9. 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 8, characterized in that: The following steps are involved: (1) Use the 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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