Energy flow modeling analysis method for hydrogen production system of alkaline electrolysis water

Abstract

The application provides an energy flow modeling analysis method of an alkaline water electrolysis hydrogen production system, which comprises the following steps: for the stack component, based on an electrochemical reaction mechanism equation and an Ohm's law, defining a reversible voltage and an activation overvoltage as a voltage source in an electrolysis cell unit, defining an Ohm's resistance according to an Ohm's overvoltage, connecting different circuit elements to obtain an electrochemical energy flow model of the stack; establishing a heat transfer energy flow model of a gas-liquid separator, the stack component, a mixer and a heat exchanger, connecting nodes with the same temperature, and establishing a system overall heat transfer energy flow model; taking an ambient temperature and a cold fluid inlet temperature as boundary conditions, and according to the electrochemical energy flow model of the stack component, the system overall heat transfer energy flow model and corresponding constraint conditions, combining system operation parameters and system structure parameters to solve the model, and obtaining an alkaline water electrolysis hydrogen production system operation analysis result. The energy flow modeling analysis method of the alkaline water electrolysis hydrogen production system provided by the application realizes the cross-scale unified modeling and analysis of the alkaline water electrolysis hydrogen production system by establishing the heat transfer energy flow model of the external system and the electrochemical energy flow model of the internal process of the stack.

Description

Technical Field

[0001] This invention relates to the field of water electrolysis for hydrogen production technology, and in particular to an energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system. Background Technology

[0002] Hydrogen energy, as a green, low-carbon, and widely applicable secondary energy source, plays a crucial role in assisting renewable energy consumption, achieving large-scale peak shaving in the power grid, and cross-seasonal and cross-regional energy storage, while promoting low-carbon development in industries, construction, and transportation. Compared to hydrogen production through fossil fuel chemical reactions, hydrogen production via water electrolysis not only has no carbon emissions but can also be combined with renewable energy power generation to help absorb renewable energy, and is currently receiving widespread attention and importance. Electrolysis converts electrical energy into the chemical energy of hydrogen gas. Electrolysis can provide flexible regulation methods for new power systems. Among these methods, alkaline water electrolysis is a mature, simple, and low-cost technology, and is currently the main method for hydrogen production via water electrolysis. Alkaline electrolysis can achieve minute-level response to input power, providing peak shaving and frequency regulation services to the power grid, improving the safety, reliability, and flexibility of the power system, and is of great significance for power grid regulation.

[0003] However, the system's energy efficiency is significantly affected by parameters such as the stack temperature. In addition, the system has many operating parameters that span multiple temporal and spatial scales, making its overall and cross-scale modeling complex. The electrical and thermal mathematical properties are quite different, resulting in the overall system model exhibiting high-dimensional, nonlinear, and implicit characteristics, making overall solution and analysis difficult. Summary of the Invention

[0004] This invention provides an energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system, which solves the difficulties in modeling, solving and analyzing alkaline water electrolysis hydrogen production systems in the prior art, and realizes cross-scale unified modeling and analysis of alkaline water electrolysis hydrogen production systems.

[0005] This invention provides an energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system, comprising the following steps: For the fuel cell stack components in the alkaline water electrolysis hydrogen production system, based on the electrochemical reaction mechanism equation and Ohm's law, taking the electrolysis chamber as a unit, defining the reversible voltage and activation overvoltage as voltage sources, defining the Ohm resistance according to the Ohm overvoltage, connecting different circuit elements to obtain the electrochemical energy flow model of the fuel cell stack, and obtaining the constraint conditions of the electrochemical energy flow model of the fuel cell stack components according to Kirchhoff's laws; for the alkaline water electrolysis hydrogen production system, establishing heat transfer energy flow models for the gas-liquid separator, fuel cell stack components, mixer, and heat exchanger. By connecting nodes with the same temperature, a system-wide heat transfer energy flow model is established. The constraints of this model are obtained based on Kirchhoff's laws. The nodes include the gas-liquid separator, the fuel cell stack components, the mixer, and the inlet and outlet of the heat exchanger. Using ambient temperature and the cold fluid inlet temperature as boundary conditions, the model is solved based on the electrochemical energy flow model and corresponding constraints of the fuel cell stack components and the system-wide heat transfer energy flow model and corresponding constraints, combined with system operating parameters and system structural parameters. This yields the operational analysis results of the alkaline water electrolysis hydrogen production system.

[0006] According to the energy flow modeling and analysis method of an alkaline water electrolysis hydrogen production system provided by the present invention, the reversible voltage is expressed as:

[0007]

[0008] in, This represents the reversible voltage. Indicates standard reversible voltage. Represents the state constant of a gas. Indicates temperature. Denotes Faraday's constant. Indicates system operating pressure. Indicates the partial pressure of water vapor. Indicates water activity in the range of 0-150 degrees Celsius;

[0009] The activation overvoltage is expressed as:

[0010]

[0011]

[0012] in, Indicates cathode activation overvoltage. Indicates the anodic activation overvoltage. Indicates the cathode transfer coefficient. Indicates the anode transfer coefficient. Indicates current density, This represents the exchange current density at the cathode. This represents the exchange current density at the anode. Indicates the bubble coverage rate on the electrode surface;

[0013] The ohmic overvoltage is expressed as:

[0014]

[0015] in, This indicates the ohmic overvoltage. Indicates cathode resistance. Indicates the anode resistance. Indicates the resistance of the electrolyte. Indicates the diaphragm resistance. This indicates the given current in the electrolysis chamber.

[0016] According to the energy flow modeling and analysis method of an alkaline water electrolysis hydrogen production system provided by the present invention, the heat transfer energy flow model of the fuel cell stack components is expressed as follows:

[0017]

[0018]

[0019]

[0020]

[0021] in, This indicates the heat generated during the electrolysis process. Indicates the number of electrolysis chambers. Indicates the cell voltage. Indicates the thermal neutral voltage. This indicates the given current in the electrolysis chamber. It represents the thermodynamic potential during the electrolysis process. This indicates the temperature of the fuel cell stack after it has been heated by the heat generated during the electrolysis process. Indicates the inlet temperature of the fuel cell stack. Indicates the electrolyte mass flow rate. Indicates the specific heat capacity of the electrolyte. This represents the thermal resistance during the heat dissipation process between the fuel cell stack and the environment. Indicates the temperature of the makeup water. This indicates the amount of heat dissipated from the fuel cell stack to the environment. This represents the product of the heat transfer coefficient between the fuel cell stack and the environment, and the heat transfer area. This represents the thermodynamic potential of the heat dissipation process between the fuel cell stack and the environment. This indicates the outlet temperature of the fuel cell stack.

[0022] According to the energy flow modeling and analysis method of the alkaline water electrolysis hydrogen production system provided by the present invention, the heat transfer energy flow model of the hydrogen separator in the gas-liquid separator is expressed as follows:

[0023]

[0024]

[0025] in, This represents the thermodynamic potential corresponding to the mixing process of a stream of fluid flowing into the hydrogen-side gas-liquid separator. This indicates the temperature of the mixture after the water supply, the water from the oxygen separator, and the original electrolyte from the hydrogen separator have been mixed. Indicates the temperature of the makeup water. Indicates the electrolyte mass flow rate. Indicates the specific heat capacity of the electrolyte. This indicates the mass flow rate of water consumed in the production of hydrogen on the hydrogen side. Indicates the outlet temperature of the fuel cell stack. This indicates the outlet temperature of the oxygen separator. This indicates the mass flow rate of hydrogen produced. This indicates the specific heat capacity of hydrogen. This indicates the thermal resistance between the hydrogen separator and the environment. This indicates the amount of heat dissipated between the hydrogen separator and the environment. This represents the product of the heat transfer coefficient between the gas-liquid separator and the environment and the heat transfer area.

[0026] According to the energy flow modeling and analysis method of the alkaline water electrolysis hydrogen production system provided by the present invention, the heat transfer energy flow model of the oxygen separator in the gas-liquid separator is expressed as follows:

[0027]

[0028]

[0029] in, This indicates the thermal resistance between the oxygen separator and the environment. Indicates the outlet temperature of the fuel cell stack. Indicates the temperature of the makeup water. This indicates the amount of heat dissipated between the oxygen separator and the environment. This represents the product of the heat transfer coefficient and the heat transfer area between the gas-liquid separator and the environment. This represents the thermodynamic potential of the oxygen separator dissipating heat from the environment. This indicates the outlet temperature of the oxygen separator. Indicates the electrolyte mass flow rate. Indicates the specific heat capacity of the electrolyte. This indicates the mass flow rate of oxygen produced. This indicates the specific heat capacity of oxygen. This indicates the mass flow rate of water consumed in the production of hydrogen on the hydrogen side.

[0030] According to the energy flow modeling and analysis method of an alkaline water electrolysis hydrogen production system provided by the present invention, the heat transfer energy flow model of the mixer is expressed as follows:

[0031]

[0032] in, This represents the mixed thermodynamic potential. This indicates the temperature at which the electrolyte at the outlet of the hydrogen separator and the electrolyte at the outlet of the oxygen separator are mixed. This indicates the outlet temperature of the hydrogen separator. This indicates the outlet temperature of the oxygen separator. Indicates the electrolyte mass flow rate. This indicates the specific heat capacity of the electrolyte.

[0033] According to the energy flow modeling and analysis method of the alkaline water electrolysis hydrogen production system provided by the present invention, the heat transfer energy flow model of the heat exchanger is expressed as follows:

[0034]

[0035]

[0036]

[0037] in, This represents the thermodynamic potential that characterizes the temperature change of a hot fluid. This indicates the temperature at which the electrolyte at the outlet of the hydrogen separator and the electrolyte at the outlet of the oxygen separator are mixed. Indicates the inlet temperature of the fuel cell stack. Indicates heat exchange. Indicates the electrolyte mass flow rate. Indicates the specific heat capacity of the electrolyte. This represents the thermodynamic potential characterizing the temperature change of a cold fluid. Indicates the cooling water outlet temperature. Indicates the cooling water inlet temperature. This indicates the mass flow rate of the cold fluid. This indicates the specific heat capacity of a cold fluid. This indicates the thermal resistance of the heat exchanger. Indicates the heat capacity flow of cold fluid. Indicates the electrolyte heat capacity flow. Indicates the number of heat transfer units for the hot fluid. This indicates the number of heat transfer units for the cold fluid.

[0038] According to the present invention, an energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system is provided. The method involves solving the model using system operating parameters and system structural parameters to obtain operational analysis results for the alkaline water electrolysis hydrogen production system. This includes: obtaining the node temperature and working fluid flow rate during system operation by combining the cooling water flow rate, electrolyte flow rate, pressure, and current from the system operating parameters, and the system structural parameters; and / or, obtaining system operational analysis results showing changes in heat exchanger heat transfer, stack temperature, and cell voltage as the cooling water flow rate changes; and / or, obtaining system operational analysis results showing changes in stack inlet and outlet temperatures and cell voltage as the electrolyte flow rate increases by combining the cooling water flow rate, electrolyte flow rate, pressure, and current from the system operating parameters, and the system structural parameters; and / or, obtaining curves showing the variation of hydrogen production rate and voltage efficiency with current density by combining the pressure and different stack temperatures from the system operating parameters, and the system structural parameters; and / or, obtaining the stack polarization curve by combining the stack temperature and pressure from the system operating parameters, and the system structural parameters.

[0039] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the energy flow modeling and analysis method of the alkaline water electrolysis hydrogen production system as described above.

[0040] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements an energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system as described above.

[0041] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the energy flow modeling and analysis method for the alkaline water electrolysis hydrogen production system as described above.

[0042] The energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system provided by this invention, based on the electrochemical reaction mechanism equation and Ohm's law, defines the reversible voltage and activation overvoltage as voltage sources for the fuel cell components in the alkaline water electrolysis hydrogen production system, taking the electrolysis chamber as a unit. It defines the Ohm resistance based on the Ohm overvoltage, connects different circuit elements to obtain the electrochemical energy flow model of the fuel cell stack, and obtains the constraints of the electrochemical energy flow model of the fuel cell components according to Kirchhoff's laws. For the alkaline water electrolysis hydrogen production system, it establishes heat transfer energy flow models for the gas-liquid separator, fuel cell components, mixer, and heat exchanger, and connects nodes with the same temperature to establish the overall heat transfer energy flow model of the system. The constraints of the overall heat transfer energy flow model of the system are obtained based on Kirchhoff's laws. The nodes include the inlet and outlet of the gas-liquid separator, fuel cell stack components, mixer, and heat exchanger. The ambient temperature and the cold fluid inlet temperature are used as boundary conditions. Based on the electrochemical energy flow model and corresponding constraints of the fuel cell stack components and the overall heat transfer energy flow model and corresponding constraints of the system, the model is solved by combining the system operating parameters and system structural parameters. The operational analysis results of the alkaline water electrolysis hydrogen production system are obtained. By establishing the heat transfer energy flow model of the external system and the electrochemical energy flow model of the internal process of the fuel cell stack, cross-scale unified modeling and analysis of the alkaline water electrolysis hydrogen production system is realized. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0044] Figure 1 This is a flowchart illustrating the energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system provided by the present invention.

[0045] Figure 2 This is a schematic diagram of the alkaline water electrolysis hydrogen production system processing flow in the energy flow modeling and analysis method provided by the present invention.

[0046] Figure 3 This is the equivalent circuit model of the electrolysis chamber in the energy flow modeling and analysis method of the alkaline water electrolysis hydrogen production system provided by the present invention.

[0047] Figure 4 This is a schematic diagram of the heat transfer energy flow model of the alkaline water electrolysis hydrogen production system in the energy flow modeling and analysis method provided by the present invention.

[0048] Figure 5This is one of the schematic diagrams of system operation analysis results in the energy flow modeling and analysis method for the alkaline water electrolysis hydrogen production system provided by the present invention.

[0049] Figure 6 This is the second schematic diagram of the system operation analysis results in the energy flow modeling and analysis method for the alkaline water electrolysis hydrogen production system provided by this invention.

[0050] Figure 7 This is the third schematic diagram of the system operation analysis results in the energy flow modeling and analysis method for the alkaline water electrolysis hydrogen production system provided by this invention.

[0051] Figure 8 This is the fourth schematic diagram of the system operation analysis results in the energy flow modeling and analysis method for the alkaline water electrolysis hydrogen production system provided by this invention.

[0052] Figure 9 This is the fifth schematic diagram of the system operation analysis results in the energy flow modeling and analysis method for the alkaline water electrolysis hydrogen production system provided by this invention.

[0053] Figure 10 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0055] Figure 1 This is a schematic flowchart of the energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system provided by the present invention. Figure 1 As shown, the method includes:

[0056] Step S1: For the fuel cell stack components in the alkaline water electrolysis hydrogen production system, based on the electrochemical reaction mechanism equation and Ohm's law, taking the electrolysis chamber as a unit, the reversible voltage and activation overvoltage are defined as voltage sources, the Ohm resistance is defined according to the Ohm overvoltage, and different circuit elements are connected to obtain the electrochemical energy flow model of the fuel cell stack. The constraints of the electrochemical energy flow model of the fuel cell stack components are obtained according to Kirchhoff's law.

[0057] In an alkaline electrolyte environment, under the influence of direct current, water on the cathode side gains electrons and undergoes a hydrogen evolution reduction reaction to generate hydrogen gas and hydroxide ions. Under the influence of the electric field and the concentration difference between the hydrogen and oxygen sides, the hydroxide ions pass through the membrane and lose electrons on the anode side to undergo an oxygen evolution oxidation reaction to generate oxygen gas and water.

[0058] When obtaining the internal electrochemical characteristics of the fuel cell stack, for an alkaline water electrolysis hydrogen production system, under a given stack structure, the voltage of a single electrolysis cell is calculated based on the Nernst equation. It is a reversible voltage The sum of overvoltages, including ohmic overvoltages caused by the resistance within the electrolytic cell. Activation overvoltage caused by the limitation of anodic and cathodic reaction kinetics Cathode concentration overvoltage The sum of these voltages, concentration overvoltages, typically generated at higher current densities, are usually negligible. Combining these voltages, the electrochemical model is represented as a circuit using Ohm's law, describing the electrochemical processes within the electrolysis process.

[0059] Step S2: For the alkaline water electrolysis hydrogen production system, establish a heat transfer energy flow model for the gas-liquid separator, fuel cell stack components, mixer, and heat exchanger; connect nodes with the same temperature to establish an overall system heat transfer energy flow model; and obtain the constraints of the overall system heat transfer energy flow model according to Kirchhoff's laws; wherein, the nodes include the inlet and outlet of the gas-liquid separator, the fuel cell stack components, the mixer, and the heat exchanger.

[0060] Based on thermodynamics and heat transfer theory, this study investigates the balance between heat generation and dissipation (lumped heat capacity method) and constructs a thermal model of the electrolytic cell, which can be used to observe the temperature change process inside the electrolytic cell over time. In recent years, the heat flow method has been extended to the steady-state and dynamic process analysis of different heat transfer and storage stages in thermodynamic systems. Furthermore, the overall constraints of the thermodynamic system are divided into linear topological constraints and nonlinear element constraints, clarifying the overall transport and conversion laws of heat within the thermodynamic system.

[0061] The following assumptions are made in the modeling of the heat transfer energy flow of the electric stack in this invention: (1) the outlet temperature of the electric stack is the average temperature of the electric stack; (2) gas cross-contamination and electro-osmosis of the diaphragm are not considered; (3) the amount of water replenished is the amount of water consumed by the chemical reaction under ideal conditions.

[0062] The following assumptions are made in the modeling of the heat transfer energy flow of the gas-liquid separator and other components in this invention: (1) all gases are ideal gases; (2) the gas-liquid separation efficiency is 1; (3) heat loss in the pipeline is ignored; (4) the specific heat capacity of the water added or consumed is equal to that of the electrolyte. Each component of the system is modeled separately, and the above models are connected according to the node temperature to construct the overall heat flow model of the system.

[0063] Step S3: Using the ambient temperature and the cold fluid inlet temperature as boundary conditions, the model is solved based on the electrochemical energy flow model of the fuel cell stack components and the corresponding constraints, the overall heat transfer energy flow model of the system and the corresponding constraints, combined with the system operating parameters and system structural parameters, to obtain the operational analysis results of the alkaline water electrolysis hydrogen production system.

[0064] Overall modeling and analysis of alkaline electrolysis systems are crucial for improving their energy efficiency. However, due to the multi-order, multi-parameter characteristics of the external thermal model and internal electrochemical model of alkaline electrolysis systems, the overall system analysis is complex. This invention achieves unified cross-scale modeling and analysis of the system by establishing a heat transfer energy flow model of the external system and an electrochemical energy flow model of the internal processes of the fuel cell stack.

[0065] Figure 2 This is a schematic diagram of the alkaline water electrolysis hydrogen production system process in the energy flow modeling and analysis method provided by this invention. (See diagram for example.) Figure 2 As shown, the alkaline water electrolysis hydrogen production system mainly includes a fuel cell stack, a hydrogen separator, an oxygen separator, an electrolyte pump, a heat exchanger, and a mixer. It also includes a purification device and an electrical system. This invention primarily establishes a steady-state heat transfer energy flow model for the fuel cell stack, the gas-liquid separator (including the hydrogen separator and the oxygen separator), the heat exchanger, and the mixer.

[0066] The internal and external characteristics and performance analysis of alkaline water electrolysis for hydrogen production are all based on steady-state variable operating conditions. The selection of each value is replaceable. By performing steady-state variable operating condition calculations on the above model, considering the influence of Faraday efficiency on the hydrogen production rate, and using voltage efficiency as the evaluation standard for system performance, the Simulink software is used to solve the problem, but not limited to any programming solver or power system simulation solver. Under given boundary conditions and operating parameters, the variation law of the internal and external characteristics of the system is obtained.

[0067] This invention, based on thermoelectric analogy, reveals the constitutive relationships of basic components in a thermal system from the perspectives of driving forces and impedance of heat transport. It combines the system's topology to describe the overall heat transport law within the system, revealing the overall physical constraints of heat transfer and conversion processes. From the perspective of dissipation and conservation, it defines impedance and potential difference-like electrical component models reflecting the energy dissipation and conservation characteristics of the electrolysis process. It proposes an equivalent modeling method for alkaline electrolysis systems isomorphic to circuit networks and reveals the overall characteristics of heat transfer and conversion during electrolysis, helping to reduce the difficulty of solving the problem and better couple it with power electronic devices.

[0068] The energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system provided by this invention, based on the electrochemical reaction mechanism equation and Ohm's law, defines the reversible voltage and activation overvoltage as voltage sources for the fuel cell components in the alkaline water electrolysis hydrogen production system, taking the electrolysis chamber as a unit. It defines the Ohm resistance based on the Ohm overvoltage, connects different circuit elements to obtain the electrochemical energy flow model of the fuel cell stack, and obtains the constraints of the electrochemical energy flow model of the fuel cell components according to Kirchhoff's laws. For the alkaline water electrolysis hydrogen production system, it establishes heat transfer energy flow models for the gas-liquid separator, fuel cell components, mixer, and heat exchanger, and connects nodes with the same temperature to establish the overall heat transfer energy flow model of the system. The constraints of the overall heat transfer energy flow model of the system are obtained based on Kirchhoff's laws. The nodes include the inlet and outlet of the gas-liquid separator, fuel cell stack components, mixer, and heat exchanger. The ambient temperature and the cold fluid inlet temperature are used as boundary conditions. Based on the electrochemical energy flow model and corresponding constraints of the fuel cell stack components and the overall heat transfer energy flow model and corresponding constraints of the system, the model is solved by combining the system operating parameters and system structural parameters. The operational analysis results of the alkaline water electrolysis hydrogen production system are obtained. By establishing the heat transfer energy flow model of the external system and the electrochemical energy flow model of the internal process of the fuel cell stack, cross-scale unified modeling and analysis of the alkaline water electrolysis hydrogen production system is realized.

[0069] According to the energy flow modeling and analysis method of an alkaline water electrolysis hydrogen production system provided by the present invention, the reversible voltage is expressed as:

[0070]

[0071] in, This represents the reversible voltage. Indicates standard reversible voltage. Represents the state constant of a gas. Indicates temperature. Denotes Faraday's constant. Indicates system operating pressure. Indicates the partial pressure of water vapor. Indicates water activity in the range of 0-150 degrees Celsius;

[0072] The activation overvoltage is expressed as:

[0073]

[0074]

[0075] in, Indicates cathode activation overvoltage. Indicates the anodic activation overvoltage. Indicates the cathode transfer coefficient. Indicates the anode transfer coefficient. Indicates current density, This represents the exchange current density at the cathode. This represents the exchange current density at the anode. Indicates the bubble coverage rate on the electrode surface;

[0076] The ohmic overvoltage is expressed as:

[0077]

[0078] in, This indicates the ohmic overvoltage. Indicates cathode resistance. Indicates the anode resistance. Indicates the resistance of the electrolyte. Indicates the diaphragm resistance. This indicates the given current in the electrolysis chamber.

[0079] Figure 3 This is the equivalent circuit model of the electrolysis chamber in the energy flow modeling and analysis method for the alkaline water electrolysis hydrogen production system provided by this invention. For example... Figure 3 As shown, the equivalent circuit model of the electrolysis chamber mainly consists of a current source, an ohmic resistor, an activation voltage source, and a reversible voltage source, describing the electrochemical processes within the electrolysis process. The main modeling methods for the electrochemical model are as follows:

[0080] The reversible voltage is the minimum voltage required for a chemical reaction to occur. It is affected by factors such as temperature, pressure, and water activity. Under non-standard conditions, it can be expressed according to the Nernst equation as:

[0081]

[0082] in, This represents the reversible voltage. This represents the standard reversible voltage, which can be expressed as a function of temperature T. Represents the state constant of a gas. Indicates temperature. Denotes Faraday's constant. Indicates system operating pressure. The partial pressure of water vapor can be expressed by an empirical formula relating the molar concentration of the alkali solution (m) and the average temperature of the fuel cell stack. It indicates water activity in the range of 0-150 degrees Celsius.

[0083] The activation overvoltage is related to the activation energy of an electrochemical reaction; it is the voltage consumed to break the equilibrium state and drive the reaction forward. Since bubbles generated during electrolysis affect the effective surface area of ​​the electrodes, the exchange current density is corrected, and the activation overvoltage is affected by the bubbles. and The calculation formula is:

[0084]

[0085]

[0086] in, Indicates cathode activation overvoltage. Indicates the anodic activation overvoltage. Indicates the cathode transfer coefficient. Indicates the anode transfer coefficient. Indicates current density, This represents the exchange current density at the cathode. This represents the exchange current density at the anode. Indicates the bubble coverage rate on the electrode surface;

[0087]

[0088]

[0089] Considering the effect of pressure on exchange current density, the formulas for calculating the exchange current density of the anode and cathode when using nickel as the electrode are:

[0090]

[0091]

[0092] in, Indicates reference pressure. Indicates the reference temperature.

[0093]

[0094] in, This represents the limiting current density, with a value of 300 kA / m. 2 . Indicates temperature The partial pressure of water vapor at that time.

[0095] The ohmic overvoltage is expressed as:

[0096]

[0097] in, This indicates the ohmic overvoltage. Indicates cathode resistance. Indicates the anode resistance. Indicates the resistance of the electrolyte. Indicates the diaphragm resistance. This indicates the given current in the electrolysis chamber.

[0098] Ohm resistor Represented as:

[0099]

[0100]

[0101] in, , , , These represent the thickness and area of ​​the anode and cathode, respectively; , This indicates the conductivity of the anode and cathode.

[0102] The formula for calculating the resistance of the electrolyte is:

[0103]

[0104] in, The electrolyte conductivity, , These represent the distances from the anode and cathode to the diaphragm, respectively. The bubbles generated during electrolysis reduce the conductivity of the electrolyte; the corrected formula for calculating electrolyte resistance is:

[0105]

[0106] Diaphragm resistor It is mainly related to its porosity, tortuosity, and cross-sectional area, as well as the electrolyte conductivity. For non-organic membranes based on Zirfon, the calculation formula is:

[0107]

[0108] in, This refers to the diaphragm thickness; For membrane porosity; Indicates the curvature of the diaphragm; This is the cross-sectional area of ​​the diaphragm.

[0109] The energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system provided by this invention realizes the model construction of reversible voltage, activation overvoltage, and ohmic overvoltage of the electrolysis chamber in the fuel cell stack.

[0110] According to the energy flow modeling and analysis method of an alkaline water electrolysis hydrogen production system provided by the present invention, the heat transfer energy flow model of the fuel cell stack components is expressed as follows:

[0111]

[0112]

[0113]

[0114]

[0115] in, This indicates the heat generated during the electrolysis process. Indicates the number of electrolysis chambers. Indicates the cell voltage. Indicates the thermal neutral voltage. This indicates the given current in the electrolysis chamber. It represents the thermodynamic potential during the electrolysis process. This indicates the temperature of the fuel cell stack after it has been heated by the heat generated during the electrolysis process. Indicates the inlet temperature of the fuel cell stack. Indicates the electrolyte mass flow rate. Indicates the specific heat capacity of the electrolyte. This represents the thermal resistance during the heat dissipation process between the fuel cell stack and the environment. Indicates the temperature of the makeup water. This indicates the amount of heat dissipated from the fuel cell stack to the environment. This represents the product of the heat transfer coefficient between the fuel cell stack and the environment, and the heat transfer area. This represents the thermodynamic potential of the heat dissipation process between the fuel cell stack and the environment. This indicates the outlet temperature of the fuel cell stack.

[0116] During electrolysis, heat is generated when the voltage exceeds the thermal neutral voltage. In the heat flow method, the temperature change of the fluid is described by a thermodynamic potential. The formulas for calculating the heat generation and the thermodynamic potential are as follows:

[0117]

[0118]

[0119] in, The value can be set to 1.48V.

[0120] The formulas for calculating the thermal resistance and thermodynamic potential of the heat dissipation process between the fuel cell stack and the environment are as follows:

[0121]

[0122]

[0123] The energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system provided by this invention realizes the construction of a heat transfer energy flow model for fuel cell stack components.

[0124] According to the energy flow modeling and analysis method of the alkaline water electrolysis hydrogen production system provided by the present invention, the heat transfer energy flow model of the hydrogen separator in the gas-liquid separator is expressed as follows:

[0125]

[0126]

[0127] in, This represents the thermodynamic potential corresponding to the mixing process of a stream of fluid flowing into the hydrogen-side gas-liquid separator. This indicates the temperature of the mixture after the water supply, the water from the oxygen separator, and the original electrolyte from the hydrogen separator have been mixed. Indicates the temperature of the makeup water. Indicates the electrolyte mass flow rate. Indicates the specific heat capacity of the electrolyte. This indicates the mass flow rate of water consumed in the production of hydrogen on the hydrogen side. Indicates the outlet temperature of the fuel cell stack. This indicates the outlet temperature of the oxygen separator. This indicates the mass flow rate of hydrogen produced. This indicates the specific heat capacity of hydrogen. This indicates the thermal resistance between the hydrogen separator and the environment. This indicates the amount of heat dissipated between the hydrogen separator and the environment. This represents the product of the heat transfer coefficient between the gas-liquid separator and the environment and the heat transfer area.

[0128] The temperature changes before and after fluid mixing are described. Makeup water temperature. Consistent with ambient temperature.

[0129] The energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system provided by this invention realizes the construction of a heat transfer energy flow model for the hydrogen separator in a gas-liquid separator.

[0130] According to the energy flow modeling and analysis method of the alkaline water electrolysis hydrogen production system provided by the present invention, the heat transfer energy flow model of the oxygen separator in the gas-liquid separator is expressed as follows:

[0131]

[0132]

[0133] in, This indicates the thermal resistance between the oxygen separator and the environment. Indicates the outlet temperature of the fuel cell stack. Indicates the temperature of the makeup water. This indicates the amount of heat dissipated between the oxygen separator and the environment. This represents the product of the heat transfer coefficient and the heat transfer area between the gas-liquid separator and the environment. This represents the thermodynamic potential of the oxygen separator dissipating heat from the environment. This indicates the outlet temperature of the oxygen separator. Indicates the electrolyte mass flow rate. Indicates the specific heat capacity of the electrolyte. This indicates the mass flow rate of oxygen produced. This indicates the specific heat capacity of oxygen. This indicates the mass flow rate of water consumed in the production of hydrogen on the hydrogen side.

[0134] The energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system provided by this invention realizes the construction of a heat transfer energy flow model for the oxygen separator in a gas-liquid separator.

[0135] According to the energy flow modeling and analysis method of an alkaline water electrolysis hydrogen production system provided by the present invention, the heat transfer energy flow model of the mixer is expressed as follows:

[0136]

[0137] in, This represents the mixed thermodynamic potential. This indicates the temperature at which the electrolyte at the outlet of the hydrogen separator and the electrolyte at the outlet of the oxygen separator are mixed. This indicates the outlet temperature of the hydrogen separator. This indicates the outlet temperature of the oxygen separator. Indicates the electrolyte mass flow rate. This indicates the specific heat capacity of the electrolyte.

[0138] Electrolytes from the hydrogen gas-liquid separator and the oxygen gas-liquid separator enter a mixer and mix to form a single electrolyte stream. After passing through a pump, the stream enters a heat exchanger for heat exchange; the pump's effect on the electrolyte temperature is negligible. The mixing process can be controlled by the mixing thermodynamic potential. describe.

[0139] The energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system provided by this invention realizes the construction of a heat transfer energy flow model for the mixer.

[0140] According to the energy flow modeling and analysis method of the alkaline water electrolysis hydrogen production system provided by the present invention, the heat transfer energy flow model of the heat exchanger is expressed as follows:

[0141]

[0142]

[0143]

[0144] in, This represents the thermodynamic potential that characterizes the temperature change of a hot fluid. This indicates the temperature at which the electrolyte at the outlet of the hydrogen separator and the electrolyte at the outlet of the oxygen separator are mixed. Indicates the inlet temperature of the fuel cell stack. Indicates heat exchange. Indicates the electrolyte mass flow rate. Indicates the specific heat capacity of the electrolyte. This represents the thermodynamic potential characterizing the temperature change of a cold fluid. Indicates the cooling water outlet temperature. Indicates the cooling water inlet temperature. This indicates the mass flow rate of the cold fluid. This indicates the specific heat capacity of a cold fluid. This indicates the thermal resistance of the heat exchanger. Indicates the heat capacity flow of cold fluid. Indicates the electrolyte heat capacity flow. Indicates the number of heat transfer units for the hot fluid. This indicates the number of heat transfer units for the cold fluid.

[0145] The mixed electrolyte enters the heat exchanger to exchange heat with the cooling water, where the thermodynamic potentials characterizing the temperature changes of the hot and cold fluids are respectively... , . This is the outlet temperature of the heat exchanger's hot fluid, and also the inlet temperature of the fuel cell's electrolyte.

[0146] Cold fluid heat capacity flow Represented as:

[0147]

[0148] In the formula The mass flow rate of the cold fluid. is the specific heat capacity of the cold fluid.

[0149]

[0150] Number of heat transfer units of the hot fluid Represented as:

[0151]

[0152] Number of heat transfer units for cold fluid Represented as:

[0153]

[0154] in, The correction factor is 1 for counter-current heat exchangers. The ambient temperature is used to calculate the intercooler fluid temperature. It is the product of the heat transfer coefficient and the heat transfer area of ​​the heat exchanger.

[0155] The energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system provided by this invention realizes the construction of a heat transfer energy flow model for the heat exchanger.

[0156] Figure 4 This is a schematic diagram of the heat transfer energy flow model of the alkaline water electrolysis hydrogen production system in the energy flow modeling and analysis method provided by this invention. It mainly consists of heat transfer energy flow models of various components such as the gas-liquid separator, fuel cell stack, heat exchanger, and mixer, connecting nodes with the same temperature together.

[0157] According to the energy flow modeling and analysis method of an alkaline water electrolysis hydrogen production system provided by the present invention, the method involves solving the model by combining system operating parameters and system structural parameters to obtain the operational analysis results of the alkaline water electrolysis hydrogen production system, including:

[0158] By combining the cooling water flow rate, electrolyte flow rate, pressure, and current in the system operating parameters, as well as the system structural parameters, the node temperature and working fluid flow rate during system operation are obtained.

[0159] And / or,

[0160] By combining the cooling water flow rate, pressure, and current in the system operating parameters, as well as the system structural parameters, the system operation analysis results are obtained, which show the changes in heat exchanger heat transfer, stack temperature, and cell voltage as the cooling water flow rate changes.

[0161] And / or,

[0162] By combining the system operating parameters such as cooling water flow rate, electrolyte flow rate, pressure, and current, as well as the system structural parameters, the system operation analysis results of the changes in stack inlet and outlet temperatures and cell voltage as the electrolyte flow rate increases are obtained.

[0163] And / or,

[0164] By combining the pressure and different stack temperatures in the system operating parameters, as well as the system structural parameters, we obtained the curves of hydrogen production rate and voltage efficiency as a function of current density.

[0165] And / or,

[0166] By combining the stack temperature and pressure from the system operating parameters with the system structural parameters, the polarization curve of the stack is obtained.

[0167] Examples of system structure parameters and system operating parameters are shown in Table 1.

[0168] Table 1

[0169]

[0170] When solving the model by combining system operating parameters and system structural parameters to obtain the operational analysis results of the alkaline water electrolysis hydrogen production system, the node temperature and working fluid flow rate during system operation can be obtained by combining the cooling water flow rate, electrolyte flow rate, pressure and current in the system operating parameters, as well as the system structural parameters.

[0171] Figure 5 This is one of the schematic diagrams of system operation analysis results in the energy flow modeling and analysis method for the alkaline water electrolysis hydrogen production system provided by the present invention. Figure 5 The diagram shows the node temperatures and working fluid flow rates in the system when the fuel cell stack operates at a cooling water flow rate of 0.3 kg / s, an electrolyte flow rate of 1.42 kg / s, a current of 3000 A, and a pressure of 16 bar. The heat transfer energy flow model and the internal equivalent circuit model of the alkaline electrolysis system have the same mathematical form, allowing for cross-scale coupling solutions. The system's equivalent circuit has only one branch, and its constraints are fully given in the system modeling. In the calculations, the reference temperature and reference pressure are 25 °C and 1 bar, respectively, and the heat exchanger... Set to 4000W / K. Other parameters are shown in Table 1.

[0172] When solving the model by combining system operating parameters and system structural parameters to obtain the operational analysis results of the alkaline water electrolysis hydrogen production system, the system operating parameters such as cooling water flow rate, pressure, and current, as well as the system structural parameters, can be combined to obtain the system operational analysis results of changes in heat exchanger heat transfer, stack temperature, and cell voltage as the cooling water flow rate changes.

[0173] Figure 6 This is the second schematic diagram of the system operation analysis results in the energy flow modeling and analysis method for the alkaline water electrolysis hydrogen production system provided by this invention. Figure 6 The results are shown when the cooling water flow rate is 0.3-0.7 kg / s, the pressure is 16 bar, and the current is 3000 A. As the cooling water flow rate increases, the heat exchanger's heat transfer capacity increases, and the fuel cell inlet temperature (heat exchanger hot fluid outlet temperature) gradually decreases. As the fuel cell temperature decreases, the cell voltage increases.

[0174] When solving the model by combining system operating parameters and system structural parameters to obtain the operational analysis results of the alkaline water electrolysis hydrogen production system, the system operating parameters such as cooling water flow rate, electrolyte flow rate, pressure, and current, as well as the system structural parameters, can be combined to obtain the system operational analysis results of the changes in stack inlet and outlet temperatures and cell voltage as the electrolyte flow rate increases.

[0175] Figure 7 This is the third schematic diagram of the system operation analysis results in the energy flow modeling and analysis method for the alkaline water electrolysis hydrogen production system provided by this invention. Figure 7The results are shown when the cooling water flow rate is 0.3 kg / s, the electrolyte flow rate is 0.6-1.4 kg / s, the pressure is 16 bar, and the current is 3000 A. As the electrolyte flow rate increases, the inlet temperature of the fuel cell stack increases significantly, while the outlet temperature decreases. The cell voltage increases slightly. This is because the heat generation of the fuel cell stack remains almost constant, but the temperature difference between the inlet and outlet of the fuel cell stack decreases as the electrolyte flow rate increases.

[0176] When solving the model by combining the system operating parameters and system structural parameters to obtain the operational analysis results of the alkaline water electrolysis hydrogen production system, the hydrogen production rate and voltage efficiency as a function of current density can also be obtained by combining the pressure and different stack temperatures in the system operating parameters and the system structural parameters.

[0177] Figure 8 This is the fourth schematic diagram of the system operation analysis results in the energy flow modeling and analysis method for the alkaline water electrolysis hydrogen production system provided by this invention. Figure 8 The curves showing the changes in hydrogen production rate and voltage efficiency with current density when the fuel cell stack is running at temperatures of 65°C, 75°C, and 85°C and a pressure of 16 bar are presented.

[0178] The system mass conservation and efficiency calculations are shown below:

[0179] During electrolysis, hydrogen is produced at the cathode and oxygen at the anode. According to Faraday's law of electrolysis, the molar rate and mass flow rate of hydrogen production are calculated as follows:

[0180]

[0181]

[0182] in, Indicates the molar rate of hydrogen production. Indicates Faraday efficiency. This indicates the number of electrons transferred in the reaction, which is 2. This indicates the mass flow rate of hydrogen production. This indicates the molar mass of hydrogen gas.

[0183]

[0184]

[0185]

[0186] Based on the chemical reaction equation for water electrolysis, the mass balance of each component is expressed as:

[0187]

[0188] The rate at which water is consumed in moles. Indicates the molar rate of oxygen production

[0189] Voltage efficiency is used as the evaluation criterion for system performance, and it is defined as the reversible voltage divided by the cell voltage:

[0190]

[0191] The results show that increasing temperature increases voltage efficiency, while increasing current density gradually decreases voltage efficiency, due to the increased overpotential caused by the increased current density. However, the hydrogen production rate increases with increasing current density. This is because the hydrogen production rate is positively correlated with current density, but increasing temperature slightly reduces Faraday efficiency; therefore, the hydrogen production rate at 65℃ is higher than that at 75℃ and 85℃.

[0192] When solving the model by combining the system operating parameters and system structural parameters to obtain the operational analysis results of the alkaline water electrolysis hydrogen production system, the stack polarization curve can also be obtained by combining the stack temperature and pressure in the system operating parameters and the system structural parameters.

[0193] Figure 9 This is the fifth schematic diagram of the system operation analysis results in the energy flow modeling and analysis method for the alkaline water electrolysis hydrogen production system provided by this invention. Figure 9 The figure shows the polarization curves of the fuel cell stack obtained by solving the electrochemical equivalent circuit model under operating conditions of 70°C and 10 bar. The shaded areas in the figure correspond to ohmic overvoltage, anode activation overvoltage, cathode activation overvoltage, and reversible voltage, respectively. The results show that the proportion of ohmic overvoltage gradually increases with increasing current density. Therefore, the fuel cell stack design should minimize ohmic resistance to improve voltage efficiency.

[0194] The energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system provided by this invention establishes an energy flow model for the alkaline water electrolysis hydrogen production system and integrates it with the equivalent circuit model of the fuel cell stack. It studies the heat and mass transfer process of the alkaline electrolysis system under different operating conditions. Taking heat flow as the core, it establishes a thermodynamic system energy flow model consistent with the power system model architecture by constraining analysis of different components such as the fuel cell stack, gas-liquid separator, heat exchanger, and mixer under steady-state processes, reflecting the resistance, capacitance, and delay characteristics in the heat transfer process.

[0195] Figure 10 A schematic diagram of the physical structure of an electronic device, such as... Figure 10The electronic device may include a processor 810, a communication interface 820, a memory 830, and a communication bus 840. The processor 810, communication interface 820, and memory 830 communicate with each other via the communication bus 840. The processor 810 can call logical instructions in the memory 830 to execute an energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system. This method includes: for the fuel cell stack components in the alkaline water electrolysis hydrogen production system, based on the electrochemical reaction mechanism equation and Ohm's law, defining reversible voltage and activation overvoltage as voltage sources, defining Ohm's resistance according to Ohm's overvoltage, connecting different circuit elements to obtain an electrochemical energy flow model of the fuel cell stack, and obtaining the constraints of the electrochemical energy flow model of the fuel cell stack components according to Kirchhoff's laws; for the alkaline water electrolysis hydrogen production system, establishing a gas-liquid separator, fuel cell stack components, mixer, and heat exchanger. A heat transfer energy flow model of the device is established by connecting nodes with the same temperature to form a system-wide heat transfer energy flow model. The constraints of this model are obtained based on Kirchhoff's laws. The nodes include the gas-liquid separator, the fuel cell stack components, the mixer, and the inlet and outlet of the heat exchanger. Using ambient temperature and the cold fluid inlet temperature as boundary conditions, the model is solved based on the electrochemical energy flow model and corresponding constraints of the fuel cell stack components and the system-wide heat transfer energy flow model and corresponding constraints, combined with system operating parameters and system structural parameters. This yields the operational analysis results of the alkaline water electrolysis hydrogen production system.

[0196] Furthermore, the logical instructions in the aforementioned memory 830 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0197] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the energy flow modeling and analysis method for the alkaline water electrolysis hydrogen production system provided by the above methods. The method includes: for the fuel cell stack components in the alkaline water electrolysis hydrogen production system, based on the electrochemical reaction mechanism equation and Ohm's law, defining the reversible voltage and activation overvoltage as voltage sources in the electrolysis chamber, defining the Ohm resistance according to the Ohm overvoltage, connecting different circuit elements to obtain the electrochemical energy flow model of the fuel cell stack, and obtaining the constraint conditions of the electrochemical energy flow model of the fuel cell stack components according to Kirchhoff's laws. For the alkaline water electrolysis hydrogen production system, a heat transfer energy flow model is established for the gas-liquid separator, fuel cell stack components, mixer, and heat exchanger. Nodes with the same temperature are connected to establish an overall system heat transfer energy flow model. The constraints of the overall system heat transfer energy flow model are obtained according to Kirchhoff's laws. The nodes include the inlet and outlet of the gas-liquid separator, fuel cell stack components, mixer, and heat exchanger. Using ambient temperature and cold fluid inlet temperature as boundary conditions, the model is solved based on the electrochemical energy flow model and corresponding constraints of the fuel cell stack components and the overall system heat transfer energy flow model and corresponding constraints, combined with system operating parameters and system structural parameters, to obtain the operational analysis results of the alkaline water electrolysis hydrogen production system.

[0198] Furthermore, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, this computer program implements an energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system provided by the methods described above. This method includes: for the fuel cell stack components in the alkaline water electrolysis hydrogen production system, based on the electrochemical reaction mechanism equation and Ohm's law, defining reversible voltage and activation overvoltage as voltage sources, taking the electrolysis chamber as a unit, defining an ohmic resistance according to the ohmic overvoltage, connecting different circuit elements to obtain an electrochemical energy flow model of the fuel cell stack, and obtaining the constraint conditions of the electrochemical energy flow model of the fuel cell stack components according to Kirchhoff's laws; for the alkaline water electrolysis hydrogen production system, A heat transfer energy flow model is established for the gas-liquid separator, fuel cell stack components, mixer, and heat exchanger. Nodes with the same temperature are connected to establish an overall system heat transfer energy flow model. The constraints of the overall system heat transfer energy flow model are obtained according to Kirchhoff's laws. The nodes include the inlet and outlet of the gas-liquid separator, fuel cell stack components, mixer, and heat exchanger. Using ambient temperature and cold fluid inlet temperature as boundary conditions, the model is solved based on the electrochemical energy flow model and corresponding constraints of the fuel cell stack components and the overall system heat transfer energy flow model and corresponding constraints, combined with system operating parameters and system structural parameters. The operational analysis results of the alkaline water electrolysis hydrogen production system are then obtained.

[0199] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0200] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0201] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for energy flow modeling and analysis of an alkaline water electrolysis hydrogen production system, characterized in that, include: For the fuel cell stack components in an alkaline water electrolysis hydrogen production system, based on the electrochemical reaction mechanism equation and Ohm's law, taking the electrolysis chamber as a unit, the reversible voltage and activation overvoltage are defined as voltage sources, the Ohm resistance is defined according to the Ohm overvoltage, and different circuit elements are connected to obtain the electrochemical energy flow model of the fuel cell stack. The constraints of the electrochemical energy flow model of the fuel cell stack components are obtained according to Kirchhoff's laws. For the alkaline water electrolysis hydrogen production system, a heat transfer energy flow model is established for the gas-liquid separator, the fuel cell stack components, the mixer, and the heat exchanger. Nodes with the same temperature are connected to establish an overall system heat transfer energy flow model. The constraints of the overall system heat transfer energy flow model are obtained according to Kirchhoff's laws. The nodes include the inlet and outlet of the gas-liquid separator, the fuel cell stack components, the mixer, and the heat exchanger. Using ambient temperature and cold fluid inlet temperature as boundary conditions, the model is solved based on the electrochemical energy flow model and corresponding constraints of the stack components, the overall heat transfer energy flow model and corresponding constraints of the system, combined with system operating parameters and system structural parameters, to obtain the operational analysis results of the alkaline water electrolysis hydrogen production system. The heat transfer energy flow model of the hydrogen separator in the gas-liquid separator is expressed as follows: ； ； in, This represents the thermodynamic potential corresponding to the mixing process of a stream of fluid flowing into the hydrogen-side gas-liquid separator. This indicates the temperature of the mixture after the water supply, the water from the oxygen separator, and the original electrolyte from the hydrogen separator have been mixed. Indicates the temperature of the makeup water. This indicates the electrolyte mass flow rate. Indicates the specific heat capacity of the electrolyte. This indicates the mass flow rate of water consumed in the production of hydrogen on the hydrogen side. Indicates the outlet temperature of the fuel cell stack. This indicates the outlet temperature of the oxygen separator. This indicates the mass flow rate of hydrogen produced. This indicates the specific heat capacity of hydrogen. This indicates the thermal resistance between the hydrogen separator and the environment. This indicates the amount of heat dissipated between the hydrogen separator and the environment. This represents the product of the heat transfer coefficient between the gas-liquid separator and the environment and the heat transfer area.

2. The energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system according to claim 1, characterized in that, The reversible voltage is expressed as: ； in, This represents the reversible voltage. Indicates standard reversible voltage. Represents the state constant of a gas. Indicates temperature. Denotes Faraday's constant. Indicates system operating pressure. Indicates the partial pressure of water vapor. Indicates water activity in the range of 0-150 degrees Celsius; The activation overvoltage is expressed as: ； ； in, Indicates cathode activation overvoltage. Indicates the anodic activation overvoltage. Indicates the cathode transfer coefficient. Indicates the anode transfer coefficient. Indicates current density, This represents the exchange current density at the cathode. This represents the exchange current density at the anode. Indicates the bubble coverage rate on the electrode surface; The ohmic overvoltage is expressed as: ； in, This indicates the ohmic overvoltage. Indicates cathode resistance. Indicates the anode resistance. Indicates the resistance of the electrolyte. Indicates the diaphragm resistance. This indicates the given current in the electrolysis chamber.

3. The energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system according to claim 1, characterized in that, The heat transfer energy flow model of the fuel cell stack component is expressed as follows: ； ； ； ； in, This indicates the heat generated during the electrolysis process. Indicates the number of electrolysis chambers. Indicates the cell voltage. Indicates the thermal neutral voltage. This indicates the given current in the electrolysis chamber. It represents the thermodynamic potential during the electrolysis process. This indicates the temperature of the fuel cell stack after it has been heated by the heat generated during electrolysis. Indicates the inlet temperature of the fuel cell stack. This indicates the electrolyte mass flow rate. Indicates the specific heat capacity of the electrolyte. This represents the thermal resistance during the heat dissipation process between the fuel cell stack and the environment. Indicates the temperature of the makeup water. This indicates the amount of heat dissipated from the fuel cell stack to the environment. This represents the product of the heat transfer coefficient between the fuel cell stack and the environment, and the heat transfer area. This represents the thermodynamic potential of the heat dissipation process between the fuel cell stack and the environment. This indicates the outlet temperature of the fuel cell stack.

4. The energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system according to claim 1, characterized in that, The heat transfer energy flow model of the oxygen separator in the gas-liquid separator is expressed as follows: ； ； in, This indicates the thermal resistance between the oxygen separator and the environment. Indicates the outlet temperature of the fuel cell stack. Indicates the temperature of the makeup water. This indicates the amount of heat dissipated between the oxygen separator and the environment. This represents the product of the heat transfer coefficient and the heat transfer area between the gas-liquid separator and the environment. This represents the thermodynamic potential of the oxygen separator dissipating heat from the environment. This indicates the outlet temperature of the oxygen separator. This indicates the electrolyte mass flow rate. Indicates the specific heat capacity of the electrolyte. This indicates the mass flow rate of oxygen produced. This indicates the specific heat capacity of oxygen. This indicates the mass flow rate of water consumed in the production of hydrogen on the hydrogen side.

5. The energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system according to claim 1, characterized in that, The heat transfer energy flow model of the mixer is expressed as follows: ； in, This represents the mixed thermodynamic potential. This indicates the temperature at which the electrolyte at the outlet of the hydrogen separator and the electrolyte at the outlet of the oxygen separator are mixed. This indicates the outlet temperature of the hydrogen separator. This indicates the outlet temperature of the oxygen separator. This indicates the electrolyte mass flow rate. This indicates the specific heat capacity of the electrolyte.

6. The energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system according to claim 1, characterized in that, The heat transfer energy flow model of the heat exchanger is expressed as follows: ； ； ； in, This represents the thermodynamic potential that characterizes the temperature change of a hot fluid. This indicates the temperature at which the electrolyte at the outlet of the hydrogen separator and the electrolyte at the outlet of the oxygen separator are mixed. Indicates the inlet temperature of the fuel cell stack. Indicates heat exchange. This indicates the electrolyte mass flow rate. Indicates the specific heat capacity of the electrolyte. This represents the thermodynamic potential characterizing the temperature change of a cold fluid. Indicates the cooling water outlet temperature. Indicates the cooling water inlet temperature. This indicates the mass flow rate of the cold fluid. This indicates the specific heat capacity of a cold fluid. This indicates the thermal resistance of the heat exchanger. Indicates the heat capacity flow of cold fluid. Indicates the electrolyte heat capacity flow. Indicates the number of heat transfer units for the hot fluid. This indicates the number of heat transfer units for the cold fluid.

7. The energy flow modeling and analysis method for an alkaline water electrolysis hydrogen production system according to claim 1, characterized in that, The model is solved by combining system operating parameters and system structural parameters to obtain the operational analysis results of the alkaline water electrolysis hydrogen production system, including: By combining the cooling water flow rate, electrolyte flow rate, pressure, and current in the system operating parameters, as well as the system structural parameters, the node temperature and working fluid flow rate during system operation are obtained. And / or, By combining the cooling water flow rate, pressure, and current in the system operating parameters, as well as the system structural parameters, the system operation analysis results are obtained, which show the changes in heat exchanger heat transfer, stack temperature, and cell voltage as the cooling water flow rate changes. And / or, By combining the system operating parameters such as cooling water flow rate, electrolyte flow rate, pressure, and current, as well as the system structural parameters, the system operation analysis results of the changes in stack inlet and outlet temperatures and cell voltage as the electrolyte flow rate increases are obtained. And / or, By combining the pressure and different stack temperatures in the system operating parameters, as well as the system structural parameters, we obtained the curves of hydrogen production rate and voltage efficiency as a function of current density. And / or, By combining the stack temperature and pressure from the system operating parameters with the system structural parameters, the polarization curve of the stack is obtained.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the energy flow modeling and analysis method for the alkaline water electrolysis hydrogen production system as described in any one of claims 1 to 7.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the energy flow modeling and analysis method for the alkaline water electrolysis hydrogen production system as described in any one of claims 1 to 7.

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