Method and device for optimizing starting process of proton exchange membrane water electrolysis hydrogen production system

Abstract

The invention provides a method and device for optimizing the starting process of a proton exchange membrane water electrolysis hydrogen production system, and the method comprises the steps: firstly building lumped parameter models of the system, including a voltage model of a proton exchange membrane electrolytic cell, a temperature model of a hydrogen production device, a hydrogen production power model and an electric energy consumption model; then, optimizing the hydrogen production efficiency in the starting process by adopting the Pontryagin minimum principle to obtain an optimal current change curve, inputting the optimal current change curve into the model to obtain a device temperature change curve, and making an MAP table based on the optimized electrolytic current and device temperature data; and finally, in the starting process of the hydrogen production system, the MAP table is inquired according to the current system temperature to obtain electrolytic current, the power supply is controlled to electrolyze with the current, and the hydrogen production efficiency in the starting process is effectively improved by properly prolonging the rising time of the system temperature in the starting process.

Description

Technical Field

[0001] The present invention relates to the field of water electrolysis hydrogen production system, and in particular to a method and device for optimizing the startup process of a proton exchange membrane water electrolysis hydrogen production system. Technical Background

[0002] The proton exchange membrane (PEM) water electrolysis hydrogen production system is suitable for combination with renewable energy power generation systems. It can better cope with the input of fluctuating power such as wind power / photovoltaic power. It has the advantages of high hydrogen purity, no pollution, compact structure, fast response speed and high current density. It is considered to be the most promising way to produce hydrogen by water electrolysis.

[0003] The PEM hydrogen production system has two working modes: voltage and current. Its electrolysis efficiency is mainly affected by the temperature of the electrolyzer. The higher the temperature, the higher the electrolysis efficiency at the same electrolysis rate. The optimal working temperature is 60-80°C, and the electrolyzer needs to be heated to the optimal working temperature during the startup process. Since the water electrolysis hydrogen production system contains a large amount of electrolyte, the system heat capacity is very high and the system temperature rise time is long. For high-power water electrolysis hydrogen production systems and working scenarios with low ambient temperatures, the startup time can even reach several hours. At present, the industry often uses the maximum voltage to start. Although this method has the advantages of high heat generation, fast temperature rise and short startup time, the efficiency is very low, and the electrolyzer temperature is low at the beginning of electrolysis. Electrolysis at the maximum voltage will result in high voltage and low current, which will damage the activity of the catalyst. Summary of the invention

[0004] The purpose of the present invention is to provide a method for optimizing the startup process of a proton exchange membrane water electrolysis hydrogen production system. The method adopts current mode startup, based on the lumped parameter model of the system, and adopts the Pontryagin minimum to optimize the electrolysis efficiency during the startup process, obtain the optimal current and temperature change curve, and make it into a MAP table. When the hydrogen production system is started, the MAP table is queried according to the current electrolyzer temperature to obtain the optimal electrolysis current, and the power supply is controlled to output the current. Compared with the traditional method of starting with maximum voltage, the system temperature rise time during the startup process is extended, which effectively improves the hydrogen production efficiency during the startup process.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A method for optimizing the startup process of a proton exchange membrane water electrolysis hydrogen production system, comprising:

[0007] Step 1, establishing a lumped parameter model of a proton exchange membrane water electrolysis hydrogen production system, including an electrolyzer voltage model, a system temperature model, a hydrogen production power model, and a power consumption model;

[0008] Step 2, using the Pontryagin minimum principle to optimize the electrolysis efficiency during the startup process to obtain the electrolysis current;

[0009] Step 3, updating the system temperature according to the lumped parameter model and the electrolysis current;

[0010] Step 4: Establish a MAP table corresponding to the system temperature and the electrolysis current

[0011] Step 5: query the MAP table according to the current system temperature, obtain the electrolysis current and input it into the system.

[0012] As a more optimal technical solution of the present invention, the step 1 is specifically as follows:

[0013] The temperature model is as follows:

[0014]

[0015] In the formula, T is the system temperature, C is the system heat capacity, i is the current density, and U is cell (T, i) is the electrolysis voltage, U th is the thermal neutral voltage, A is the active area of ​​the electrolytic cell, N cell is the number of monomers contained in the electrolytic cell, R is the thermal resistance between the system and the environment, T amb is the ambient temperature;

[0016] The voltage model is as follows:

[0017]

[0018] Where R is the universal gas constant, F is the Faraday constant, is the hydrogen pressure, is the oxygen pressure, α is the charge transfer coefficient, i 0 (T) is the exchange current density, r(T) is the resistance, i L (T) is the limiting current density;

[0019] The electric power consumption model is as follows:

[0020]

[0021] Where W P The electrical energy consumed;

[0022] The hydrogen production power model is as follows:

[0023]

[0024] In the formula, is the hydrogen energy produced, H LV It is the lower heating value of hydrogen.

[0025] As a more optimal technical solution of the present invention, the step 2 is specifically as follows:

[0026] Step 2.1, start the system at the maximum current density, and obtain the hydrogen production energy, power consumption and hydrogen production efficiency according to the lumped parameter model;

[0027] Step 2.2, calculate the co-state factor according to the hydrogen production energy, the electric energy consumed and the cross-sectional conditions;

[0028] Step 2.3, select the initial value of the co-state factor;

[0029] Step 2.4, select the current density that minimizes the Hamiltonian function in the feasible region;

[0030] Step 2.5, updating the co-state factor according to the co-state equation and current density;

[0031] Step 2.6: Update the system temperature according to the temperature model and the current density, and repeat steps 2.3 to 2.5 until the terminal moment is reached.

[0032] As a more optimal technical solution of the present invention, the cross-sectional condition in step 2.2 is as follows:

[0033]

[0034] As a more optimal technical solution of the present invention, the step 2.3 is specifically as follows:

[0035] Step 2.3.1. Select the current density as the limiting current density. When the system temperature reaches the desired temperature, calculate the electric energy, hydrogen energy and hydrogen production efficiency J consumed during the startup process according to the lumped parameter model. 0 ;

[0036] Step 2.3.2: Select the covariance factor λ according to the transversal condition P ,λ H The initial value of is as follows:

[0037]

[0038] Step 2.3.3. Adjust the covariance factor λ T The initial value of the power consumed during the startup, hydrogen energy and hydrogen production efficiency J are updated according to the optimization results. 1 ;

[0039] Step 2.3.4: If the updated hydrogen production efficiency J 1 Less than the calculated hydrogen production efficiency J 0 , then the updated hydrogen production efficiency J 1 Assign a value to the calculated hydrogen production efficiency J 0 , repeat steps 2.3.2 to 2.3.4.

[0040] As a more optimal technical solution of the present invention, the updating of the co-state factor according to the co-state equation in step 2.5 is as follows:

[0041]

[0042] Another object of the present invention is to provide a device for optimizing the startup process of a proton exchange membrane water electrolysis hydrogen production system, comprising:

[0043] Model building module, used to establish the lumped parameter model of the proton exchange membrane water electrolysis hydrogen production system;

[0044] The electrolysis efficiency optimization module uses the Pontryagin minimum principle to optimize the electrolysis efficiency during the startup process to obtain the electrolysis current;

[0045] A temperature calculation module, which updates the system temperature according to the lumped parameter model and the electrolysis current;

[0046] MAP table establishment module, establishes a MAP table corresponding to the system temperature and the electrolysis current

[0047] The query and control module queries the MAP table according to the current system temperature, obtains the electrolysis current and inputs it into the system.

[0048] Another object of the present invention is to provide an electronic device, comprising a processor and a memory, wherein the processor is used to execute a computer program stored in the memory to implement the above-mentioned method for optimizing the startup process of the proton exchange membrane water electrolysis hydrogen production system.

[0049] The present invention also has a computer-readable storage medium, wherein the computer-readable storage medium stores at least one instruction, and when the at least one instruction is executed by a processor, the above-mentioned proton exchange membrane water electrolysis hydrogen production system startup process optimization method is implemented.

[0050] The beneficial effects are as follows:

[0051] Compared with the traditional method of starting with maximum voltage, the optimization method proposed in the present invention has been verified to prolong the system temperature rise time during the startup process and effectively improve the hydrogen production efficiency during the startup process. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a schematic diagram of the optimization method of the present invention.

[0053] Figure 2 It is a schematic diagram of the optimization method and parameter adjustment of the present invention.

[0054] Figure 3 This is the structural diagram of the water electrolysis hydrogen production system.

[0055] Figure 4 It is a MAP diagram of temperature and current.

[0056] Figure 5 This is a simulation result diagram (efficiency) comparing the optimization method of Example 1 of the present invention and the traditional maximum voltage startup method.

[0057] Figure 6 This is a simulation result diagram (temperature) comparing the optimization method of Example 1 of the present invention and the traditional maximum voltage startup method.

[0058] Figure 7 It is a structural block diagram of the optimization device of the present invention.

[0059] Figure 8 It is a structural block diagram of the electronic device of the present invention. DETAILED DESCRIPTION

[0060] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0061] The following detailed description is an exemplary description, which is intended to provide further detailed description of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present application belongs. The terms used in the present invention are only for describing specific embodiments, and are not intended to limit exemplary embodiments according to the present invention.

[0062] like Figure 3 The structure diagram of the proton exchange membrane water electrolysis hydrogen production system is shown, including a proton exchange membrane electrolyzer, a power supply system, a temperature sensor and a control unit; the proton exchange membrane electrolyzer is the place for the water decomposition hydrogen production reaction; the power supply system is used to provide a stable DC power supply for the proton exchange membrane electrolyzer; the temperature sensor is used to monitor the temperature of the proton exchange membrane electrolyzer; the control unit is used to collect the signal of the temperature sensor and send a control signal to the power supply system. The power supply system can be a rectifier system; the control unit can be an ECU (Electronic Control Unit);

[0063] Example 1

[0064] like Figure 1 As shown, the present invention provides a method for optimizing the startup process of a proton exchange membrane water electrolysis hydrogen production system, comprising the following steps:

[0065] Step 1: Establish a lumped parameter model of the system, including a voltage model of the proton exchange membrane electrolyzer, a temperature model of the hydrogen production system, a hydrogen production power model, and an electric energy consumption model;

[0066] The temperature model is as follows:

[0067]

[0068] In the formula, T is the system temperature, C is the system heat capacity, i is the current density, and U is cell (T, i) is the electrolysis voltage, U th is the thermal neutral voltage, A is the active area of ​​the electrolytic cell, N cell is the number of monomers contained in the electrolytic cell, R is the thermal resistance between the system and the environment, T amb is the ambient temperature.

[0069] The voltage model is as follows:

[0070]

[0071] Where R is the universal gas constant, F is the Faraday constant, is the hydrogen pressure, is the oxygen pressure, α is the charge transfer coefficient, i 0 (T) is the exchange current density, r(T) is the resistance, i L (T) is the limiting current density.

[0072] The electric power consumption model is as follows:

[0073]

[0074] Where W P For the electrical energy consumed.

[0075] The hydrogen production power model is as follows:

[0076]

[0077] In the formula, is the hydrogen energy produced, H LV It is the lower heating value of hydrogen.

[0078] Step 2: Use the Pontryagin minimum principle to optimize the hydrogen production efficiency during the startup process, obtain the optimal current change curve, and input it into the model to obtain the system temperature change curve, and make a MAP table based on the optimized electrolysis current and system temperature data; finally, during the system startup process, query the MAP table according to the current system temperature to obtain the electrolysis current, and input it into the power supply system.

[0079] like Figure 2 The figure shows a flow chart of the Pontryagin minimum principle optimization method and its parameter selection. The Pontryagin minimum principle optimization method comprises the following steps:

[0080] Step 2.1: Select the performance indicator as the hydrogen production efficiency during the startup process, as shown in the following formula:

[0081]

[0082] Step 2.2: Determine the constraints as follows:

[0083]

[0084] Step 2.3: Determine the Ha density function as follows:

[0085]

[0086] Step 2.4: Select the co-state factor λ T , P , H Initial value.

[0087] Step 2.5: Under the condition of satisfying the constraints, select the current density that minimizes the Hamiltonian function, as follows:

[0088]

[0089] Step 2.6: Update the co-state factor according to the co-state equation, as follows:

[0090]

[0091]

[0092] Step 2.7: Based on the temperature model and the current density i calculated in step 5 * Update the system temperature and repeat steps 2.5, 2.6, and 2.7 until the terminal time is reached.

[0093] In the formula, J is the performance index, λ T , P , H is the co-factor, T r is the desired electrolytic cell temperature, H is the Hamiltonian function, t f The terminal moment.

[0094] The initial value of the co-state factor can be selected by the following steps:

[0095] Step 2.3.1: Select the current density as the limiting current density and calculate according to the lumped parameter model. When the system temperature reaches the desired temperature T r When the power consumed during the startup process is recorded, the power W P (t f ), the energy of hydrogen produced Hydrogen production efficiency J 0 ;

[0096] Step 2.3.2: Select the covariance factor λ according to the transversality condition P (t f ), λ H (t f ) is as follows:

[0097]

[0098] Step 2.3.3: Adjust the covariance factor λ T The initial value of the system temperature in the optimization result can be f Time reaches T r , update the power W consumed during startup according to the optimization results P (t f ), the energy of hydrogen produced Record updated hydrogen production efficiency J 1 .

[0099] Step 2.3.4: If the performance index J 1 Less than J 0 , then J 1 Assign to J 0 , repeat steps 2.3.2 to 2.3.4.

[0100] In Example 1, the system heat capacity C = 190 kJ / K, the activation area A = 125 cm 2 , the number of monomers contained in the electrolytic cell is N cell =23, thermal resistance between system and environment R = 0.022K / J, ambient temperature T amb =298.15K, terminal time t f =4000s, expected temperature T r =333K. Figure 4 The MAP diagram of temperature and current obtained by optimization is shown as follows: Figure 5 and 6 The simulation results are shown. It can be seen that compared with the traditional method of starting with maximum voltage, the optimization method proposed in the present invention increases the temperature rise time by 700s and improves the hydrogen production efficiency by 1.83%.

[0101] Example 2

[0102] like Figure 6As shown, based on the same inventive concept as the above-mentioned embodiment 1, the present invention also provides a proton exchange membrane water electrolysis hydrogen production system startup process optimization device, including a model building module, which is used to establish a lumped parameter model of the proton exchange membrane water electrolysis hydrogen production system; an electrolysis efficiency optimization module, which uses the Pontryagin minimum principle to optimize the electrolysis efficiency during the startup process to obtain the electrolysis current; a temperature calculation module, which updates the system temperature according to the lumped parameter model and the electrolysis current; a MAP table establishment module, which establishes a MAP table query and control module corresponding to the system temperature and the electrolysis current, and queries the MAP table according to the current system temperature to obtain the electrolysis current and input it into the system.

[0103] Example 3

[0104] like Figure 7 As shown, the present invention also provides an electronic device. If the module / unit integrated in the electronic device is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the above-mentioned method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. Computer-readable media may include: any entity or device capable of carrying computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory and read-only memory (ROM, Read-Only Memory).

[0105] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0106] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing device to work in a specific way, so that the instructions stored in the computer-readable memory produce a product including an instruction device, which implements the functions specified in the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0107] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0108] 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 above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for optimizing the startup process of a proton exchange membrane water electrolysis hydrogen production system, characterized in that: The steps include: Step 1, establishing a lumped parameter model of a proton exchange membrane water electrolysis hydrogen production system, including an electrolyzer voltage model, a system temperature model, a hydrogen production power model, and a power consumption model; Step 2, using the Pontryagin minimum principle to optimize the electrolysis efficiency during the startup process to obtain the electrolysis current; Step 3, updating the system temperature according to the lumped parameter model and the electrolysis current; Step 4: Establish a MAP table corresponding to the system temperature and the electrolysis current Step 5: query the MAP table according to the current system temperature, obtain the electrolysis current and input it into the system.

2. The method for optimizing the startup process of a proton exchange membrane water electrolysis hydrogen production system according to claim 1, characterized in that: The step 1 is specifically as follows: The temperature model is as follows: In the formula, T is the system temperature, C is the system heat capacity, i is the current density, U cell (T, i) is the electrolysis voltage, U th is the thermal neutral voltage, A is the active area of ​​the electrolytic cell, N cell is the number of monomers contained in the electrolytic cell, R is the thermal resistance between the system and the environment, T amb is the ambient temperature; The voltage model is as follows: Where R is the universal gas constant, F is the Faraday constant, is the hydrogen pressure, is the oxygen pressure, α is the charge transfer coefficient, i0(T) is the exchange current density, r(T) is the resistance, i L (T) is the limiting current density; The electric power consumption model is as follows: Where W P The electrical energy consumed; The hydrogen production power model is as follows: In the formula, is the hydrogen energy produced, H LV It is the lower heating value of hydrogen.

3. The method for optimizing the startup process of a proton exchange membrane water electrolysis hydrogen production system according to claim 1, characterized in that: The step 2 is specifically as follows: Step 2.1, start the system at the maximum current density, and obtain the hydrogen production energy, power consumption and hydrogen production efficiency according to the lumped parameter model; Step 2.2, calculate the co-state factor according to the hydrogen production energy, the electric energy consumed and the cross-sectional conditions; Step 2.3, select the initial value of the co-state factor; Step 2.4, select the current density that minimizes the Hamiltonian function in the feasible region; Step 2.5, updating the co-state factor according to the co-state equation and current density; Step 2.6: Update the system temperature according to the temperature model and the current density, and repeat steps 2.3 to 2.5 until the terminal moment is reached.

4. The method for optimizing the startup process of a proton exchange membrane water electrolysis hydrogen production system according to claim 3, characterized in that: The cross-sectional condition in step 2.2 is as follows:

5. The method for optimizing the startup process of a proton exchange membrane water electrolysis hydrogen production system according to claim 3, characterized in that: The step 2.3 is as follows: Step 2.3.1, select the current density as the limiting current density, and when the system temperature reaches the desired temperature, calculate the electric energy, hydrogen energy and hydrogen production efficiency J0 consumed during the startup process according to the lumped parameter model; Step 2.3.2: Select the covariance factor λ according to the transversal condition P ,λ H The initial value of is as follows: Step 2.3.

3. Adjust the covariance factor λ T The initial value of is used to update the electric energy consumed during the startup process, hydrogen energy and hydrogen production efficiency J1 according to the optimization results; Step 2.3.4: If the updated hydrogen production efficiency J1 is less than the calculated hydrogen production efficiency J0, the updated hydrogen production efficiency J1 is assigned to the calculated hydrogen production efficiency J0, and steps 2.3.2 to 2.3.4 are repeated.

6. The method for optimizing the startup process of a proton exchange membrane water electrolysis hydrogen production system according to claim 3, characterized in that: The updating of the co-state factor according to the co-state equation in step 2.5 is as follows:

7. A device for optimizing the startup process of a proton exchange membrane water electrolysis hydrogen production system, characterized in that: include Model building module, used to establish the lumped parameter model of the proton exchange membrane water electrolysis hydrogen production system; The electrolysis efficiency optimization module uses the Pontryagin minimum principle to optimize the electrolysis efficiency during the startup process to obtain the electrolysis current; A temperature calculation module, which updates the system temperature according to the lumped parameter model and the electrolysis current; A MAP table establishment module establishes a MAP table query and control module corresponding to the system temperature and the electrolysis current, queries the MAP table according to the current system temperature, obtains the electrolysis current and inputs it into the system.

8. An electronic device, characterized in that: It comprises a processor and a memory, wherein the processor is used to execute a computer program stored in the memory to implement the startup process optimization method of the proton exchange membrane water electrolysis hydrogen production system as claimed in claim 1.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores at least one instruction, and when the at least one instruction is executed by the processor, the startup process optimization method of the proton exchange membrane water electrolysis hydrogen production system as claimed in claim 1 is implemented.

Images