Optimal configuration method for multiple sets of hydrogen production electrolytic cells

Abstract

The invention discloses an optimal configuration method for multiple sets of hydrogen production electrolytic cells, which belongs to the field of electrolytic hydrogen production control and comprises the following steps: building an ALK single-cell model considering electric heating characteristics; building an ALK group operation model considering the rotation value; building a PEM model considering start-stop characteristics; based on the ALK single-tank model, the ALK group operation model and the PEM model, an electrolytic cell hydrogen production system large model in which an ALK hydrogen production system and a PEM hydrogen production system are operated in a combined mode is constructed, and dispatching operation is conducted in a value rotation mode; designing a target function for the large model of the electrolytic cell hydrogen production system; performing target optimization on the large model of the electrolytic cell hydrogen production system by adopting a sequential traversal method; and carrying out optimal configuration on the electrolytic cell hydrogen production system. According to the method, under the condition that the injection power curve of the electrolytic hydrogen production system is given, different ALK electrolytic cell grouping schemes and different matching modes of the ALK electrolytic cell and the PEM electrolytic cell are compared, and a combination mode with the excellent efficiency, the high stability and the high economical efficiency is obtained.

Description

Technical Field

[0001] The present invention relates to the field of electrolytic hydrogen production control, and in particular to an optimized configuration method for multiple sets of hydrogen production electrolyzers. Background Art

[0002] Hydrogen production by electrolyzing water is a clean and sustainable way of hydrogen production, with significant advantages of no pollution and zero emissions. It can be used as a flexible load and is highly compatible with various renewable energies, effectively solving the intermittency and unpredictability problems of renewable energy power generation. Through hydrogen production by electrolyzing water, excess renewable energy can be stored by converting it into hydrogen, which can effectively enhance the flexibility and efficiency of the power system and is an important part of the new power system. In addition, high-purity hydrogen can be directly used in various downstream industries to reduce production costs.

[0003] The currently more commonly used hydrogen production by electrolyzing water solutions mainly include alkaline electrolyzed water (the full name is Alkaline Electrolyzed Water, and the alkaline electrolyzer is abbreviated as ALK) and proton exchange membrane electrolyzed water (the English full name is Proton Exchange Membrane, and the proton exchange membrane electrolyzer is abbreviated as PEM). The alkaline electrolyzed water technology started earlier and has a higher maturity, but the hydrogen production efficiency is low and the start-stop response is slow. In contrast, the proton exchange membrane electrolyzed water technology has a higher electrolyzed water efficiency and dynamic response speed, and can quickly adjust the hydrogen production to cope with the change of injection power, but the production cost is high.

[0004] At present, most large-scale renewable energy hydrogen production projects use alkaline electrolyzers with low cost and large single-unit scale. Relevant research mainly focuses on the modeling and simulation of proton exchange membrane technology and the coupling of hydrogen production and wind-solar power generation, etc. The optimization objectives also mostly focus on simple economy.

[0005] In view of this, there is a lack of an efficient, economic and stable electrolyzed water hydrogen production optimization model in this technical field that can combine the advantages of PEM and ALK hydrogen production technologies, design and compare different ALK and PEM cooperation schemes, and consider factors such as electrolyzer rotation, electrolyzer group operation, and electrolyzer temperature decay. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an optimized configuration method for multiple sets of hydrogen production electrolyzers, considering the coordinated operation of the PEM hydrogen production system and the ALK hydrogen production system, where the ALK operates in groups; key factors such as the coordination between PEM and ALK, the rotation of ALK electrolyzers, group operation, temperature decay, start-up loss, investment cost, and operation and maintenance cost are considered in the model. Given the injection power curve of the electrolytic hydrogen production system, it is possible to compare different ALK electrolyzer grouping schemes and different cooperation methods between ALK and PEM electrolyzers, and obtain a combination method with better efficiency, higher stability, and stronger economy.

[0007] To solve the above technical problem, the technical solution adopted by the present invention is as follows:

[0008] An optimized configuration method for multiple sets of hydrogen production electrolyzers, comprising the following steps:

[0009] Step 1, build an ALK single-cell model considering electrothermal characteristics;

[0010] Step 2, build an ALK group operation model considering rotation;

[0011] Step 3, build a PEM model considering start-stop characteristics;

[0012] Step 4, based on the built ALK single-cell model, the built ALK group operation model, and the built PEM model, construct a large electrolyzer hydrogen production system model for the combined operation of the ALK hydrogen production system and the PEM hydrogen production system, and use the rotation method to schedule and operate the large electrolyzer hydrogen production system model; the ALK hydrogen production system is responsible for stable hydrogen production, and the PEM hydrogen production system is responsible for responding to input fluctuations;

[0013] Step 5, design an objective function for the large electrolyzer hydrogen production system model considering high efficiency, stability, and economy;

[0014] Step 6, use the sequential traversal method to optimize the objective of the large electrolyzer hydrogen production system model;

[0015] Step 7, optimize the configuration of the electrolyzer hydrogen production system.

[0016] A further improvement of the technical solution of the present invention lies in: in Step 1, the electrothermal characteristics include the rated production capacity of the ALK single cell, the electric power of the ALK single cell, the operating range of the ALK single cell, the rated operating temperature of the ALK single cell, the start-up time of the ALK single cell, the temperature decay characteristic of the ALK single cell, and the temperature rise characteristic of the ALK single cell; the ALK single-cell model specifically includes the following content:

[0017] 1.1, the rated production capacity of the ALK single cell: the rated hydrogen production capacity of the ALK single cell, denoted as C sg ;

[0018] 1.2, Electric power of a single ALK cell: The installed power of the electrolyzer is denoted as P sg0 ;

[0019] 1.3, Operating range of a single ALK cell: If the minimum output of a single unit is considered to be 40% of the installed power and the maximum output is 110% of the installed power, then the operating power limit of a single ALK cell is:

[0020] 0.4P sg0 < P sg < 1.1P sg0

[0021] Among them, 0.4P sg0 is the minimum output of a single ALK cell, denoted as P sgmin ; 1.1P sg0 is the maximum output of a single ALK cell, denoted as P sgmax ;

[0022] 1.4, Rated operating temperature of a single ALK cell: Considering the rated operating temperature of a single ALK cell is 85°C. When the temperature is lower than the rated operating temperature, it is called the starting state. In this state, the electrolyzer cannot produce hydrogen at full power and there is a certain hydrogen loss; the ratio of hydrogen loss to hydrogen supply power is a constant, called the loss coefficient, denoted as c;

[0023] 1.5, Starting time of a single ALK cell: Considering the full cold start time is 1 hour, starting from room temperature of 20°C;

[0024] 1.6, Temperature decay characteristic of a single ALK cell: Considering the temperature decay curve of a single ALK cell conforms to Newton's law of cooling, specifically:

[0025] T t = T env +(T 01 - T env )×e (-t / K1)

[0026] Among them, T t is the electrolyzer temperature at time t; T env is the ambient temperature, taking room temperature of 20°C in the calculation; T 01 is the initial temperature when the electrolyzer stops operating; K1 is the time constant, taking 14.3; t is the time, with the unit of hour;

[0027] 1.7, Temperature rise characteristic of a single ALK cell: Considering the temperature rise curve of a single ALK cell is:

[0028] T t = min{T 02 + t×K2, T max}

[0029] Among them, T t is the electrolytic cell temperature at time t; T 02 is the initial temperature at the start of the electrolytic cell; T max is the rated operating temperature of the electrolytic cell, 85 °C; K2 is the time constant, taken as 65; t is the time, with the unit of hour.

[0030] A further improvement in the technical solution of the present invention lies in: in step 2, the rotation includes: the number range of monomer cells within the ALK group, the upper and lower limits of the operation of the ALK group, the in-group sequential rotation method of the ALK group, the sequential rotation method of each group of the ALK group, the critical value of adding and subtracting electrolytic cells within the ALK group, the critical value of adding and subtracting the electrolytic cell group of the ALK group, the start-stop characteristics of the ALK group, and the start-up loss of the ALK group; the ALK group operation model specifically includes the following contents:

[0031] 2.1, the number range of monomer cells within the ALK group: the number of electrolytic cells within an ALK group is 1 ≤ N ALK ≤ 4;

[0032] 2.2, the upper and lower limits of the operation of the ALK group: considering the operation range of the ALK group is:

[0033]

[0034] Among them, 0.5P sg is 50% of the rated output of a single electrolytic cell, denoted as P stmin ; ∑1.1P sgmax is the sum of the maximum outputs of all electrolytic cells within the group, denoted as P stmax ;

[0035] 2.3, the in-group sequential rotation method of the ALK group: first sort the electrolytic cells within the group from left to right. When the number of working electrolytic cells within the group needs to increase, start the electrolytic cells from the right of the current last running one; when the number of working electrolytic cells within the group needs to decrease, turn off the electrolytic cells from the right of the current first running one;

[0036] 2.4, the sequential rotation method of each group of the ALK group: first sort the electrolytic cell groups from left to right. When the number of working electrolytic cell groups needs to increase, start the electrolytic cell groups from the right of the current last running one; when the number of working electrolytic cell groups needs to decrease, turn off the electrolytic cell groups from the right of the current first running one;

[0037] 2.5, the critical value of adding and subtracting electrolytic cells within the ALK group: when the power P st assigned to the electrolytic cell group is greater than the sum of the maximum powers of the currently running electrolytic cells ∑P sgmax , add open an electrolytic cell; when the power P stLess than the sum of the minimum powers ∑P of the currently operating electrolyzers sgmin When this occurs, stop the electrolyzers, and determine the number to be added or subtracted based on the surplus or deficit power and the operating range of the power of the unstarted electrolyzers;

[0038] 2.6, Critical value for adding or subtracting electrolyzer groups in the ALK group: When the power P for alkaline hydrogen production ALK is greater than the sum of the maximum powers ∑P of the currently operating electrolyzer groups stmax start additional electrolyzer groups; when the power P for alkaline hydrogen production ALK is less than the sum of the minimum powers ∑P of the currently operating electrolyzer groups stmin stop the electrolyzer groups, and determine the number of groups to be added or subtracted based on the surplus or deficit power and the operating range of the power of the unstarted electrolyzer groups;

[0039] 2.7, Start - stop characteristics of the ALK group: Consider that when the power P of the ALK group st is greater than or equal to the minimum output P of the ALK group stmin each electrolyzer in the non - operating state within the group is in a hot standby state, and there is no loss during startup; when the entire ALK group is shut down, each electrolyzer within the group is in a cold standby state, and losses are considered during startup, and the loss amount is determined based on the loss coefficient, shutdown time, and temperature before startup;

[0040] 2.8, Startup loss of the ALK group: Since it is assumed that each electrolyzer within the ALK group is in an operating or hot standby state during operation, the startup loss of the ALK electrolyzers only exists during the startup of the entire group; the startup loss of the ALK electrolyzers is related to the startup time, and the startup time is related to the temperature of the electrolyzers during startup;

[0041] Consider the startup loss of a single ALK group as:

[0042] P loss =(85 - T t-1 ) / (85 - 20)×P×c

[0043] where P loss is the startup loss of the electrolyzer group; T t-1 is the temperature of the electrolyzer group during startup; P is the electric power of the electrolyzer group after full startup; c is the loss coefficient, taking 0.12.

[0044] A further improvement of the technical solution of the present invention is that in step 2, consider that the electrolyzers in the ALK group preferably adopt the same grouping method, but when the total number of electrolyzers cannot be evenly divided by the number of electrolyzers in a single group, there will be a situation where the number of electrolyzers in one ALK group is less than that in other groups, and such a group is called an unbalanced group; the calculation method of the operating range of the unbalanced group is the same as that of the balanced group:

[0045] 0.5P sg ≤Pst ≤∑1.1P sgmax

[0046] The unbalanced group participates in the rotation operation of the ALK group with the same rotation strategy, and only the calculation method is different when considering the addition group critical value, that is, the addition electrolytic cell group critical value is the product of the number of cells in the unbalanced group and the maximum operating power of a single cell.

[0047] A further improvement of the technical solution of the present invention lies in: in step 3, the start-stop characteristics include: the monomer rated production capacity of the PEM, the monomer rated electric power of the PEM, the operating range of the PEM, the start-up time of the PEM, the start-up loss of the PEM, and the rotation mode of the PEM; in the PEM model, there are several PEM electrolytic cells, but the PEM electrolytic cell monomers independently participate in hydrogen production and do not operate in groups. Specifically, it includes the following content:

[0048] 3.1, the monomer rated production capacity of the PEM electrolytic cell: The monomer rated production capacity of the PEM electrolytic cell is denoted as C PEM ;

[0049] 3.2, the monomer rated electric power of the PEM electrolytic cell: The rated electric power of the PEM electrolytic cell is denoted as P PEM0 ;

[0050] 3.3, the operating range of the PEM electrolytic cell: Considering the actual operating power range of the PEM electrolytic cell is:

[0051] 0.1P PEM0 ≤P PEM ≤1.5P PEM0 ;

[0052] Among them, 0.1P PEM0 is denoted as P PEMmin ; 1.5P PEM0 is denoted as P PEMmax ;

[0053] 3.4, the start-up time of the PEM electrolytic cell: Considering the start-up time of the PEM electrolytic cell is 10 minutes;

[0054] 3.5, the start-up loss of the PEM electrolytic cell: Simplify the start-up loss of the PEM model to 12% of the average power during the start-up process;

[0055] 3.6, the rotation mode of the PEM electrolytic cell: The operating range of a single PEM electrolytic cell is:

[0056] 0.1P PEM0 ≤P PEM ≤1.5P PEM0

[0057] When the electric power used in the PEM electrolyzer exceeds the upper and lower limits of the operating range, addition and subtraction operations are performed on the PEM electrolyzer, and start-up losses are counted.

[0058] A further improvement of the technical solution of the present invention lies in: in step 4, it specifically includes the following steps:

[0059] 4.1. Combine the current installed capacity and grouping situation of the electrolyzer to determine the addition and subtraction group critical values of the PEM model, the ALK balanced group, the ALK unbalanced group, and the addition and subtraction cell critical values of the ALK single cell;

[0060] 4.2. Calculate the change in the injection power P1 of the large model of the electrolyzer hydrogen production system at present. First, perform addition and subtraction operations on the PEM electrolyzer in the PEM model to ensure the stable operation of the ALK group as much as possible;

[0061] 4.3. When the injection power fluctuation exceeds the adjustment ability of the PEM model, calculate the overflow power P2 that the PEM model cannot adjust and allocate it to the ALK group for adjustment; when the injection power fluctuation is less than the adjustment ability of the PEM model, calculate the missing power P3;

[0062] 4.4. Compare the overflow power P2 or the missing power P3 with the addition and subtraction group critical values of the ALK group, and perform operations to increase or decrease the ALK group;

[0063] 4.5. When it is necessary to increase the ALK group, start the electrolyzer group from the right side of the end of the current operation. When it is necessary to reduce the ALK group, shut down the electrolyzer group from the right side of the beginning of the current operation;

[0064] 4.6. When the operating power of the ALK group changes, compare the power fluctuation value within the group with the addition and subtraction cell critical values, and consider whether it is necessary to start or shut down the electrolyzer; when it is necessary to increase the electrolyzer within the ALK group, start the electrolyzer from the right side of the end of the current operation. When it is necessary to reduce the electrolyzer within the ALK group, shut down the electrolyzer from the right side of the beginning of the current operation.

[0065] A further improvement of the technical solution of the present invention lies in: in step 5, the considered indicators are the electro-hydrogen conversion efficiency, the start-stop times of the ALK, and the unit hydrogen production cost. The optimization result can not only ensure economic benefits but also achieve efficient utilization of energy and improve the service life of the alkaline hydrogen production equipment; the specific calculation methods of the various parameters in the optimization target are:

[0066] (1) High efficiency: The efficiency variable of the electrolyzer hydrogen production system is used to judge the electro-hydrogen conversion efficiency of the hydrogen production system, and the calculation formula is:

[0067] η = E Hp / E inj

[0068] Among them, E HpElectric energy for efficient hydrogen production, E inj is the electric energy injected into the electrolyzer hydrogen production system;

[0069] (2) Stability: The stability variable of the electrolyzer hydrogen production system is characterized by the average number of starts and stops per single ALK cell, K:

[0070] K = N s / N cell

[0071] where N s is the total number of starts and stops of all ALK electrolyzers throughout the year, and N cell is the number of ALK electrolyzers configured in the electrolyzer hydrogen production system;

[0072] (3) Economy: The economy of the electrolyzer hydrogen production system is characterized by the cost per unit of hydrogen production; the hydrogen production cost of the electrolyzer hydrogen production system is divided into four parts, including the initial investment cost and operation and maintenance cost of ALK and PEM in the electrolyzer hydrogen production system; the specific calculation formula is:

[0073]

[0074] where Cost is the cost per unit of hydrogen production, C inv1 , C inv2 are the initial investment costs of ALK and PEM respectively, Y1 and Y2 are the system operation lives of ALK and PEM respectively, C mat1 , C mat2 are the operation and maintenance costs of ALK and PEM respectively, and A H is the hydrogen production;

[0075] (4) Comprehensive objective function:

[0076] In the electrolyzer hydrogen production system, considering the linear combination of the three parameters of high efficiency, stability and economy, the weights are selected based on engineering experience after parameter normalization. The specific combination method is as follows:

[0077] η is given a coefficient of -2; K is given a coefficient of 3 and divided by 400 to unify the order of magnitude; Cost is given a coefficient of 9 and divided by 1000 to unify the order of magnitude; the final objective function used for the electrolyzer hydrogen production system is:

[0078]

[0079] The smaller the objective function, the better the electrolyzer hydrogen production system.

[0080] A further improvement of the technical solution of the present invention lies in: in step 6, the specific process of the sequential traversal method is as follows: use a double-layer nested loop body, the outer loop body traverses the number of electrolyzers in a single ALK group, taking an integer from 1 to 4; the inner loop body traverses the total number of ALK electrolyzers, taking an integer from 1 to the maximum number of electrolyzers according to the injection power scale;

[0081] For each loop, calculate the objective function value of the electrolyzer hydrogen production system and store the parameters corresponding to the minimum objective function up to the current loop; if the objective function of the current loop is less than the stored data, update the stored data; after the sequential traversal program runs to completion, output the minimum objective function and the corresponding parameters.

[0082] A further improvement of the technical solution of the present invention lies in: in step 7, the process of the optimal configuration specifically includes the following steps:

[0083] 7.1, input the parameters of the electrothermal characteristics of the single ALK cell model, the parameters of the rotation value of the ALK group operation model, the parameters of the start-stop characteristics of the PEM model, the 8760-hour power supply for hydrogen production, the unit investment cost of a single ALK cell, the unit investment cost of the PEM electrolyzer, the ALK operation and maintenance cost, and the PEM operation and maintenance cost;

[0084] 7.2, combine the 8760-hour power curve for hydrogen production to calculate the maximum number of ALK electrolyzers and the maximum number of PEM electrolyzers that can be installed;

[0085] 7.3, calculate the working state of the electrolyzers for 8760 hours, calculate the operating states of the ALK group and the PEM electrolyzers for each hour in a rotation manner, and the operating states of each electrolyzer in the ALK group;

[0086] 7.4, after running the annual data, count the electricity-to-hydrogen conversion efficiency, the average start-stop times of a single ALK cell, the unit hydrogen supply cost, and calculate the objective function;

[0087] 7.5, apply steps 7.3 and 7.4 to calculate all the configuration schemes of the single ALK cells and the ALK groups, and select the scheme with the minimum objective function as the recommended scheme.

[0088] Due to the adoption of the above technical solution, the technical progress achieved by the present invention is:

[0089] 1. The present invention realizes the organic combination of two electrolytic hydrogen production devices, namely alkaline hydrogen production and proton exchange membrane hydrogen production, and can give full play to the flexibility advantage of proton exchange membrane hydrogen production and the low-cost advantage of alkaline hydrogen production in an electrolytic hydrogen production system.

[0090] 2. In the planning stage, the present invention takes into account parameters such as electrolyzer grouping, complete sets, temperature changes, operating range, rotation duty, start-up losses, and commissioning costs, making it closer to the engineering reality and the electrolyzer configuration more comprehensive and reasonable.

[0091] 3. The optimization objective of the present invention adds hydrogen production efficiency and stability indicators on the basis of the commonly used economic objectives, which can not only improve the friendliness of the hydrogen production system to downstream hydrogen-consuming equipment, but also extend the service life of the hydrogen production equipment and reduce energy waste.

[0092] 4. The present invention is applicable to different requirements. The model used in the present invention can flexibly adjust the weights of various parameters in the objective function according to customer requirements to meet the optimization needs of various customers (such as attaching more importance to hydrogen production efficiency, more importance to economy, etc.).

[0093] 5. Compared with the commonly used machine learning algorithms in the power system optimization model, the model used in the present invention limits the number of adjustable variables, enabling the model to perform optimization using the sequential traversal method. Compared with the machine learning optimization algorithms commonly used for multi-variable optimization, simple sequential traversal can reduce the computational amount of the computer and prevent the model from falling into local optima from the source. BRIEF DESCRIPTION OF THE DRAWINGS

[0094] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts;

[0095] Figure 1 It is the rotation duty and addition / subtraction group logic diagram of the ALK group provided in the present invention;

[0096] Figure 2 It is the rotation duty and addition / subtraction group logic diagram of each cell in the ALK group provided in the present invention;

[0097] Figure 3 It is the power distribution logic diagram of ALK and PEM provided in the present invention;

[0098] Figure 4 It is the large model calculation flow chart of the electrolyzer hydrogen production system for the combined operation of the ALK hydrogen production system and the PEM hydrogen production system provided in the present invention;

[0099] Figure 5 It is the power supply curve graph for 8760 hours of hydrogen production in the project in the embodiment of the present invention;

[0100] Figure 6 It is the hourly curve graph of the operating power of the ALK electrolytic hydrogen production system in the embodiment of the present invention;

[0101] Figure 7 These are the schematic diagrams of the start-stop states of the corresponding electrolyzers in the embodiments of the present invention. Detailed implementation manners

[0102] It should be noted that the terms "including" and "having" and any variations thereof in the description and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0103] The present invention will be further described in detail below with reference to the drawings and embodiments:

[0104] As Figure 1-4 shown, an optimized configuration method for multiple sets of hydrogen production electrolyzers specifically includes the following content:

[0105] Step 1: Build an ALK single cell model considering electrothermal characteristics;

[0106] Parameters such as the rated production capacity of the ALK single cell, the electric power of the ALK single cell, the operating range of the ALK single cell, the rated operating temperature of the ALK single cell, the start-up time of the ALK single cell, the temperature decay characteristic of the ALK single cell, and the temperature rise characteristic of the ALK single cell are considered in the ALK single cell model. The ALK single cell model specifically includes:

[0107] (1) Rated production capacity of the ALK single cell: The rated hydrogen production capacity of the ALK single cell, denoted as C sg ;

[0108] (2) Operating power (electric power) of the ALK single cell: The installed power of the ALK single cell, denoted as P sg0 ;

[0109] (3) Operating range of the ALK single cell: If the minimum output of a single unit is considered to be 40% of the installed power and the maximum output is 110% of the installed power, then the operating power limit of the ALK single cell is:

[0110] 0.4P sg0 < P sg < 1.1P sg0

[0111] Among them, 0.4P sg0 is the minimum output of the ALK single cell, denoted as P sgmin ; 1.1P sg0 is the maximum output of the ALK single cell, denoted as P sgmax ;

[0112] (4) Rated operating temperature of the ALK single cell: Considering that the rated operating temperature of the ALK single cell is 85°C, when the temperature is lower than the rated operating temperature, it is called the start-up state. In this state, the electrolyzer cannot produce hydrogen at full power and there is a certain hydrogen loss. The ratio of hydrogen loss to hydrogen supply power is a constant, called the loss coefficient, denoted as c;

[0113] (5) Start-up time of the ALK single cell: Considering that the full cold start-up time is 1 hour (starting from room temperature of 20°C);

[0114] (6) Temperature decay characteristic of the ALK single cell: Considering that the temperature decay curve of the ALK single cell conforms to Newton's law of cooling, specifically:

[0115] T t =T env +(T 01 -T env )×e (-t / K1)

[0116] Where, T t is the electrolyzer temperature at time t; T env is the ambient temperature, taking 20°C at room temperature in the calculation; T 01 is the initial temperature when the electrolyzer stops running; K1 is the time constant. According to engineering experience, it is found that the electrolyzer drops to room temperature in about 2 - 3 days, taking 14.3; t is the time, in hours;

[0117] (7) Temperature rise characteristic of the ALK single cell: According to engineering experience, it takes about 1 hour for the alkaline electrolyzer to reach the operating temperature from room temperature. Considering that the measurement at the planning stage is mostly at the hour level, the temperature rise process can be regarded as a linear process. Therefore, consider the temperature rise curve of the ALK single cell as:

[0118] T t =min{T 02 +t×K2,T max}

[0119] Where, T t is the electrolyzer temperature at time t; T 02 is the initial temperature when the electrolyzer starts; T max is the rated operating temperature of the electrolyzer, 85°C; K2 is the time constant, taking 65; t is the time, in hours.

[0120] Step 2, establish an ALK group operation model considering rotation;

[0121] In the ALK group operation model, parameters such as the number range of monomer cells within the ALK group, the upper and lower limits of ALK group operation, the in-group sequential rotation method of the ALK group, the sequential rotation method of each ALK group, the critical value of adding or subtracting electrolytic cells within the ALK group, the critical value of adding or subtracting the electrolytic cell group of the ALK group, the start-stop characteristics of the ALK group, and the start-up loss of the ALK group are considered. The ALK group operation model specifically includes the following contents:

[0122] (1) The number range of monomer cells within the ALK group: The number of electrolytic cells within an ALK electrolytic cell group. Considering the actual project, it is temporarily stipulated that 1 ≤ N ALK ≤ 4.

[0123] (2) The upper and lower limits of ALK group operation: After the ALK electrolytic cells operate in groups, the operation range can be significantly improved. Considering the actual project, the operation range of the ALK group is as follows:

[0124]

[0125] Among them, 0.5P sg is 50% of the rated output of a single electrolytic cell, denoted as P stmin ; ∑1.1P sgmax is the sum of the maximum outputs of all electrolytic cells within the group, denoted as P stmax .

[0126] (3) The in-group sequential rotation method of the ALK group: In order to ensure that the working states of the electrolytic cells within the ALK group are as balanced as possible, the electrolytic cell rotation method is adopted in the ALK group operation model to select the working electrolytic cells.

[0127] First, sort the electrolytic cells within the group from left to right;

[0128] When the number of working electrolytic cells within the group needs to increase, start the electrolytic cells from the right of the current last operating one;

[0129] When the number of working electrolytic cells within the group needs to decrease, close the electrolytic cells from the right of the current first operating one.

[0130] The rotation method can ensure that the start-stop times of the alkaline electrolytic cells within the group are as average as possible to ensure that the operating states of the electrolytic cells are as balanced as possible.

[0131] (4) The sequential rotation method of each ALK group: In order to ensure that the working states of each ALK electrolytic cell group are as balanced as possible, the electrolytic cell group rotation method is adopted in the ALK group operation model to select the working electrolytic cell groups.

[0132] First, sort the electrolytic cell groups from left to right;

[0133] When the number of working electrolytic cell groups needs to increase, start the electrolytic cell groups from the right of the current last operating one;

[0134] When the number of working electrolyzer groups needs to be reduced, the electrolyzer groups are turned off from the first running position to the right.

[0135] (5) Critical value for adding or subtracting electrolyzers within an ALK group:

[0136] When the power P allocated to the electrolyzer group st is greater than the sum of the maximum powers ∑P of the currently running electrolyzers sgmax an electrolyzer is added;

[0137] When the power P allocated to the electrolyzer group st is less than the sum of the minimum powers ∑P of the currently running electrolyzers sgmin an electrolyzer is shut down;

[0138] The number of electrolyzers added or subtracted is determined based on the surplus or deficit power and the operating range of the power of the unactivated electrolyzers.

[0139] (6) Critical value for adding or subtracting electrolyzer groups in an ALK group:

[0140] When the power P for alkaline hydrogen production ALK is greater than the sum of the maximum powers ∑P of the currently running electrolyzer groups stmax an electrolyzer group is added;

[0141] When the power P for alkaline hydrogen production ALK is less than the sum of the minimum powers ∑P of the currently running electrolyzer groups stmin an electrolyzer group is shut down;

[0142] The number of electrolyzer groups added or subtracted is determined based on the surplus or deficit power and the operating range of the power of the unactivated electrolyzer groups.

[0143] (7) Start-stop characteristics of an ALK group:

[0144] In the ALK group operation model, considering when the power P of the ALK group st is greater than or equal to the minimum output P of the ALK group stmin each electrolyzer in the non-running state within the group is in a hot standby state, and there is no loss during startup.

[0145] When the entire ALK group is shut down, each electrolyzer within the group is in a cold standby state, and losses are considered during startup. The loss amount is determined based on the loss coefficient, shutdown time, temperature before startup, etc.

[0146] (8) Startup loss of an ALK group:

[0147] Since the ALK group operation model assumes that all electrolyzers in the ALK group are in operation or hot standby state during operation, the start-up loss of the ALK electrolyzer only exists during the start-up of the whole group. The start-up loss of the ALK electrolyzer is related to the start-up time, and the start-up time is related to the temperature of the electrolyzer at start-up. In the ALK group operation model, the start-up loss of a single ALK group is considered as:

[0148] P loss =(85 - T t-1 ) / (85 - 20) × P × c

[0149] Where, P loss is the start-up loss of the electrolyzer group, T t-1 is the temperature of the electrolyzer group at start-up, P is the electric power of the electrolyzer group after full start-up, and c is the loss coefficient, which is taken as 0.12 according to engineering experience.

[0150] (9) Unbalanced group treatment of the ALK group: It is considered that the ALK electrolyzers try to adopt the same grouping method. However, when the total number of electrolyzers cannot be divided evenly by the number of electrolyzers in a single group, there will be a situation where the number of electrolyzers in one ALK group is less than that in other groups. Such a group is called an unbalanced group.

[0151] The calculation method of the operating range of the unbalanced group is the same as that of the balanced group:

[0152]

[0153] The unbalanced group participates in the rotation operation of the ALK group by adopting the same rotation strategy. Only the calculation method is slightly different when considering the critical value of adding a group, that is, the critical value of adding an electrolyzer group is the product of the number of electrolyzers in the unbalanced group and the maximum operating power of a single electrolyzer.

[0154] Step 3: Build a PEM model considering start-stop characteristics;

[0155] In the PEM model, parameters such as the monomer rated production capacity of the PEM electrolyzer, the monomer rated electric power of the PEM electrolyzer, the operating range of the PEM electrolyzer, the start-up time of the PEM electrolyzer, and the start-up loss of the PEM electrolyzer are considered. In the PEM model, there are several PEM electrolyzers, but the PEM electrolyzer monomers participate in hydrogen production independently and do not operate in groups. Specifically, it includes the following content:

[0156] (1) Monomer rated production capacity of the PEM electrolyzer: The monomer rated production capacity (hydrogen production amount) of the PEM electrolyzer is denoted as C PEM ;

[0157] (2) Monomer rated electric power of the PEM electrolyzer: The rated electric power (installed power) of the PEM electrolyzer is denoted as P PEM0 ;

[0158] (3) The operating range of the PEM electrolyzer is relatively wide. Considering the actual engineering situation, it can operate for a long time within the range of 10% - 150% of the installed power. Therefore, the actual operating power range of the PEM electrolyzer is considered as:

[0159] 0.1P PEM0 ≤P PEM ≤1.5P PEM0 ;

[0160] Among them, 0.1P PEM0 is denoted as P PEMmin ; 1.5P PEM0 is denoted as P PEMmax ;

[0161] (4) The start-up time of the PEM electrolyzer: The PEM electrolyzer starts up relatively quickly. In the model, its start-up time is considered to be 10 minutes;

[0162] (5) The start-up loss of the PEM electrolyzer: Since the start-up time of the PEM electrolyzer is short, its start-up loss is simplified to 12% of the average power during the start-up process in the PEM model;

[0163] (6) The rotation mode of the PEM electrolyzer: Considering minimizing starts and stops as much as possible, the operating range of a single PEM electrolyzer is:

[0164] 0.1P PEM0 ≤P PEM ≤1.5P PEM0

[0165] When the electric power used for the PEM electrolyzer exceeds the upper and lower limits of the operating range, addition and subtraction operations are performed on the PEM electrolyzer, and the start-up loss is accounted for.

[0166] Step 4, based on the ALK single-cell model built in Step 1, the ALK group operation model built in Step 2, and the PEM model built in Step 3, construct a large model of the electrolytic cell hydrogen production system for the combined operation of the ALK hydrogen production system and the PEM hydrogen production system, and use the rotation mode to schedule and operate the large model of the electrolytic cell hydrogen production system;

[0167] In the electrolytic cell hydrogen production system, the alkaline electrolyzer (ALK) hydrogen production system and the proton exchange membrane electrolyzer (PEM) hydrogen production system operate in combination. Among them, the alkaline electrolyzer hydrogen production system has the advantages of low hydrogen production cost and large hydrogen production capacity, so it is mainly responsible for stable hydrogen production. The proton exchange membrane electrolyzer hydrogen production system has the advantages of fast response speed and large working range, so it is mainly responsible for responding to input fluctuations. The specific rotation mode scheduling operation includes the following steps:

[0168] (1) Combine the current installed capacity and grouping situation of the electrolytic cells to determine the addition and subtraction critical values of the PEM electrolytic cells, the balanced group of the ALK group, the unbalanced group of the ALK group, and the addition and subtraction critical values of a single ALK cell;

[0169] (2) Calculate the change in the injection power P1 of the current electrolytic cell hydrogen production system. First, perform addition and subtraction operations on the PEM electrolytic cells to ensure the stable operation of the ALK group as much as possible;

[0170] (3) When the fluctuation of the injection power exceeds the adjustment capacity of the PEM electrolytic cells, calculate the overflow power P2 that cannot be adjusted by the PEM electrolytic cells and allocate it to the alkaline electrolytic cells for adjustment; when the fluctuation of the injection power is less than the adjustment capacity of the PEM electrolytic cells, calculate the missing power P3;

[0171] (4) Compare the overflow power P2 or the missing power P3 with the addition / subtraction critical values of the alkaline electrolytic cell group and perform addition / subtraction operations on the electrolytic cell group;

[0172] (5) When adding or subtracting the ALK group, the addition and subtraction strategy follows the specified rotation method of each group in the ALK group, that is, when adding a group, start the electrolytic cell group from the end of the current operation to the right, and when subtracting a group, shut down the electrolytic cell group from the first place of the current operation to the right;

[0173] (6) When the operating power of the ALK group changes, compare the power fluctuation value within the group with the addition and subtraction electrolytic cell critical values and consider whether to start or shut down the electrolytic cells. When adding or subtracting electrolytic cells within the ALK group, the addition and subtraction strategy follows the specified rotation method within the ALK group, that is, when adding a cell, start the electrolytic cell from the end of the current operation to the right, and when subtracting a cell, shut down the electrolytic cell from the first place of the current operation to the right.

[0174] Step 5: Design an objective function that considers efficiency, stability, and economy for the large model of the electrolytic cell hydrogen production system in which the ALK hydrogen production system and the PEM hydrogen production system operate jointly constructed in Step 4;

[0175] The large model of this electrolytic cell hydrogen production system adopts an objective function that comprehensively considers efficiency, stability, and economy. The indicators are mainly the electro-hydrogen conversion efficiency, the start-stop times of the ALK, and the unit hydrogen production cost. While ensuring economic benefits, the optimization results of the electrolytic cell hydrogen production system can also achieve efficient utilization of energy and extend the service life of alkaline hydrogen production equipment. The specific calculation methods of each parameter in the optimization objective are as follows:

[0176] (1) Efficiency: The efficiency variable of the electrolytic cell hydrogen production system is used to judge the electro-hydrogen conversion efficiency of the electrolytic cell hydrogen production system, and the calculation formula is:

[0177] η = E Hp / E inj

[0178] Among them, E HpElectric energy for efficient hydrogen production, E inj is the electric energy injected into the electrolyzer hydrogen production system; (2) Stability: The stability variable of the electrolyzer hydrogen production system is characterized by the average number of starts and stops per single cell K of the alkaline electrolyzer:

[0179] K = N s / N cell

[0180] where N s is the number of starts and stops of all ALK electrolyzers throughout the year, and N cell is the number of ALK electrolyzers configured in the electrolyzer hydrogen production system; A lower number of starts and stops is beneficial for reducing startup losses, increasing hydrogen production stability, and the lifespan of the electrolyzer hydrogen production system.

[0181] (3) Economy: The economy of the electrolyzer hydrogen production system is characterized by the unit hydrogen production cost.

[0182] The hydrogen production cost of the electrolyzer hydrogen production system is divided into four parts, including the initial investment costs and operation and maintenance costs of ALK and PEM in the electrolyzer hydrogen production system; The specific calculation formula is:

[0183]

[0184] where Cost is the unit hydrogen production cost, C inv1 , C inv2 are the initial investment costs of ALK and PEM respectively, Y1 and Y2 are the system operation lifespans of ALK and PEM respectively, C mat1 , C mat2 are the operation and maintenance costs of ALK and PEM respectively, and A H is the hydrogen production;

[0185] (4) Comprehensive objective function:

[0186] In this large model of the electrolyzer hydrogen production system, the above three parameters are considered for linear combination. After parameter normalization, the weights are selected in combination with engineering experience. The specific combination method is as follows:

[0187] η is given a coefficient of -2; K is given a coefficient of 3 and divided by 400 to unify the order of magnitude; Cost is given a coefficient of 9 and divided by 1000 to unify the order of magnitude; Finally, the objective function used in this large model of the electrolyzer hydrogen production system is:

[0188]

[0189] The smaller the objective function, the better the electrolyzer hydrogen production system.

[0190] Step 6, use the sequential traversal method to perform objective optimization on the large model of the electrolyzer hydrogen production system with the combined operation of the ALK hydrogen production system and the PEM hydrogen production system constructed in Step 4;

[0191] There are only two adjustment variables in the large model of this electrolytic cell hydrogen production system, namely the total number of ALK cells and the number of cells within a single ALK group. Other input parameters are calculated based on the above two parameters and relevant technical limitations. Considering that the number of adjustable parameters in this electrolytic cell hydrogen production system is small and the adjustment range of each parameter is not large (the number of cells within a single ALK group can only take integers from 1 to 4, and the total number of ALK cells is determined according to the scale of the hydrogen production plant, usually not exceeding 1000 at most and can only take integers). Existing optimization algorithms (such as PSO) are often more suitable for complex situations with multiple variables, with a relatively large computational amount and a risk of falling into local optima. After comprehensive consideration, the sequential traversal method is adopted in the optimization process of this electrolytic cell hydrogen production system. The specific process of the sequential traversal method is as follows:

[0192] Use a double-layer nested loop. The outer loop traverses the number of cells within a single ALK group, taking integers from 1 to 4;

[0193] The inner loop traverses the total number of ALK cells, taking integers from 1 to the maximum number of cells according to the injection power scale.

[0194] For each loop, calculate the objective function value of the electrolytic cell hydrogen production system and store the parameters corresponding to the minimum objective function up to the current loop. If the objective function of the current loop is less than the stored data, update the stored data. After the sequential traversal method program runs to completion, output the minimum objective function and the corresponding parameters.

[0195] Step 7, optimize the configuration of the large model of the electrolytic cell hydrogen production system in which the ALK hydrogen production system and the PEM hydrogen production system operate jointly constructed in step 4.

[0196] In practical applications, the optimization configuration process is as follows:

[0197] 7.1, Input the parameters of the electrothermal characteristics of the ALK single-cell model, the parameters of the rotation value of the ALK group operation model, the parameters of the start-stop characteristics of the PEM model, the 8760-hour power supply for hydrogen production, the unit investment cost of the ALK single cell, the unit investment cost of the PEM electrolytic cell, the ALK operation and maintenance cost, and the PEM operation and maintenance cost;

[0198] 7.2, Combine the 8760-hour power curve for hydrogen production to calculate the maximum number of allowable installed ALK electrolytic cells and the maximum number of PEM electrolytic cells;

[0199] 7.3, Calculate the working state of the electrolytic cells for 8760 hours, calculate the operating states of the ALK group and the PEM electrolytic cells for each hour according to the rotation value method, and the operating states of each electrolytic cell within the ALK group;

[0200] 7.4, After running the full-year data, statistically analyze the electricity-to-hydrogen conversion efficiency, the average start-stop times of each ALK single cell, the hydrogen supply cost per unit, and calculate the objective function;

[0201] 7.5, Apply Steps 7.3 and 7.4 to calculate the configuration schemes of all ALK single cells and ALK groups, and select the scheme with the minimum objective function as the recommended scheme.

[0202] Example

[0203] Taking a wind-solar hydrogen production project in a certain area as an example, the multi-group electrolyzer optimization configuration method provided by the present invention is used to optimize the configuration of multi-group electrolyzers.

[0204] 1. Basic parameters:

[0205] The technical parameters of the alkaline electrolyzer equipment and proton exchange membrane electrolyzer equipment used in this project are as shown in Table 1 below:

[0206] Table 1 Comparison table of key technical parameters of electrolyzers

[0207]

[0208]

[0209] The economic parameters of the alkaline electrolyzer equipment and proton exchange membrane electrolyzer equipment used in this project are as shown in Table 2 below:

[0210] Table 2 Comparison table of key economic parameters of electrolyzers

[0211] Category ALK PEM Investment cost (yuan / kW) 1200 6000 Operation and maintenance cost (% / year) 4％ 5％ Lifespan (years) 25 25 Cost reduction for 4 to 1 5.0％ -- Cost reduction for 3 to 1 3.3％ -- Cost reduction for 2 to 1 1.7％ --

[0212] 2. System power supply curve

[0213] In this example, 290 MW of wind power and 200 MW of photovoltaic power are configured, and the hydrogen production scale is 34,000 Nm³ per hour (where 33,000 Nm³ per hour is used for direct hydrogen supply, and 0.1×10⁴ Nm³ per hour is used for hydrogen production and storage). The annual theoretical power generation of new energy is about 1.243 billion kWh, and the annual hydrogen production volume is about 210 million Nm³, which can meet the hydrogen demand for 106,000 tons of synthetic ammonia.

[0214] Through the optimal scheduling of wind-solar energy storage, the power supply curve for hydrogen production in this project is as Figure 5 shown.

[0215] 3. Calculation results

[0216] Substitute the above data into the large model of the electrolytic cell hydrogen production system for the combined operation of the ALK hydrogen production system and the PEM hydrogen production system, and optimize the hydrogen production configuration of multiple sets of electrolytic cells. The parameter selection and results obtained after optimizing the large model of the electrolytic cell hydrogen production system for the combined operation of the ALK hydrogen production system and the PEM hydrogen production system are shown in the following table. It is recommended not to configure PEM electrolytic cells, but to configure 31 ALK electrolytic cells, with 4 in a group, a total of 8 groups, and the last group is an unbalanced group with 3 electrolytic cells configured in the group. It is estimated that the project's electricity-to-hydrogen conversion efficiency can reach 99.9685%, the average number of starts and stops of the ALK cells throughout the year is 367.68 times / year, and the unit hydrogen supply cost is 788.44 yuan / ton. Due to the high cost of PEM and the increased flexibility after ALK is grouped, PEM is not recommended for the time being. As the cost of PEM decreases in the later stage, PEM will become competitive. As shown in Table 3 below:

[0217] Table 3 Optimization Results of Hydrogen Production Configuration for Multiple Sets of Electrolytic Cells

[0218] Total number of ALK cells 31 Number of cells in a single ALK group 4 Total number of PEM cells 0 Electricity-to-hydrogen conversion efficiency 99.9685％ Average start-stop times of ALK cells 367.68 times / year Unit hydrogen supply cost 788.44 yuan / ton

[0219] Among them, in multiple consecutive typical days under the optimal allocation, the hourly curve of the operating power of the ALK electrolytic hydrogen production system is as Figure 6 shown, operating between the maximum and minimum hydrogen production powers.

[0220] The start-stop status of each corresponding electrolytic cell is as Figure 7 shown. It can be seen from Figure 7 that the start-up sequence of the ALK electrolytic cell group follows the direction from the end of the number to the larger number, and the shutdown follows the direction from the first number to the larger number, balancing the operating time of each electrolytic cell to the greatest extent and reducing the impact of start-stop operations on the service life of the electrolytic cell, which has a certain feasibility.

[0221] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for optimizing the configuration of a multi-group hydrogen electrolysis cell, characterized in that, It includes the following steps: Step 1: Build an ALK single-cell model considering electrothermal characteristics; Step 2: Build an ALK stack operation model considering rotation shift; Step 3: Build a PEM model considering start-stop characteristics; Step 4: Based on the built ALK single-cell model, the built ALK stack operation model, and the built PEM model, construct a large-scale electrolyzer hydrogen production system model for the combined operation of the ALK hydrogen production system and the PEM hydrogen production system, and schedule and operate the large-scale electrolyzer hydrogen production system model in a rotation shift manner; the ALK hydrogen production system is responsible for stable hydrogen production, and the PEM hydrogen production system is responsible for responding to input fluctuations; Step 5: Design an objective function for the large-scale electrolyzer hydrogen production system model considering high efficiency, stability, and economy; Step 6: Use the sequential traversal method to optimize the objective of the large-scale electrolyzer hydrogen production system model; Step 7: Optimize the configuration of the electrolyzer hydrogen production system.

2. The optimized configuration method for a multi-group hydrogen production electrolytic cell according to claim 1, wherein In Step 1, the electrothermal characteristics include the rated production capacity of the ALK single cell, the electric power of the ALK single cell, the operating range of the ALK single cell, the rated operating temperature of the ALK single cell, the start-up time of the ALK single cell, the temperature decay characteristic of the ALK single cell, and the temperature rise characteristic of the ALK single cell; the ALK single-cell model specifically includes the following: 1.1, Rated production capacity of the ALK single cell: The rated hydrogen production capacity of the ALK single cell, denoted as C sg ; 1.2, Electric power of the ALK single cell: The installed power of the electrolyzer, denoted as P sg0 ; 1.3, Operating range of the ALK single cell: If the minimum output of a single unit is considered to be 40% of the installed power and the maximum output is 110% of the installed power, the operating power limit of the ALK single cell is: 0.4P sg0 <P sg <1.1P sg0 Among them, 0.4P sg0 is the minimum output of a single ALK cell, denoted as P sgmin ; 1.1P sg0 is the maximum output of a single ALK cell, denoted as P sgmax ; 1.4, Rated operating temperature of the ALK single cell: Considering the rated operating temperature of the ALK single cell is 85°C, when the temperature is lower than the rated operating temperature, it is called the start-up state. In this state, the electrolyzer cannot produce hydrogen at full power and there is a certain hydrogen loss; the ratio of hydrogen loss to hydrogen supply power is a constant, called the loss coefficient, denoted as c; 1.5, Start-up time of the ALK single cell: Considering the full cold start-up time is 1 hour, starting from room temperature of 20°C; 1.6, Temperature decay characteristic of the ALK single cell: Considering the temperature decay curve of the ALK single cell conforms to Newton's law of cooling, specifically: T t = T env + (T 01 - T env ) × e (-t / K1) Among them, T t is the electrolytic cell temperature at time t; T env is the ambient temperature, and the room temperature of 20°C is taken in the calculation; T 01 is the initial temperature when the electrolytic cell stops operating; K1 is the time constant, taken as 14.3; t is the time, with the unit of hour; 1.7, Temperature rise characteristic of the ALK single cell: Considering the temperature rise curve of the ALK single cell is: T t = min{T 02 + t × K2, T max} Among them, T t is the electrolytic cell temperature at time t; T 02 is the initial temperature when the electrolytic cell starts; T max is the rated operating temperature of the electrolytic cell, 85°C; K2 is the time constant, taken as 65; t is the time, with the unit of hour.

3. A method for optimizing the configuration of a multi-group hydrogen production electrolytic cell according to claim 1, characterized in that In Step 2, the rotation shift includes: the number range of single cells within the ALK stack, the upper and lower limits of the ALK stack operation, the in-group sequential rotation shift method of the ALK stack, the sequential rotation shift method of each ALK stack, the critical value of adding or subtracting electrolyzers within the ALK stack, the critical value of adding or subtracting the electrolyzer stack of the ALK stack, the start-stop characteristics of the ALK stack, and the start-up loss of the ALK stack; the ALK stack operation model specifically includes the following: 2.1, Number range of monomer cells within the ALK group: The number of electrolytic cells within one ALK group is 1 ≤ N ALK ≤ 4; 2.2, Upper and lower limits of the ALK stack operation: Considering the operating range of the ALK stack is: 0.5P sg ≤P st ≤∑1.1P sgmax Among them, 0.5P sg is 50% of the rated output of a single electrolytic cell, denoted as P stmin ; ∑1.1P sgmax is the sum of the maximum outputs of all electrolytic cells in the group, denoted as P stmax ; 2.3, In-group sequential rotation shift method of the ALK stack: First, sort the electrolyzers within the group from left to right. When the number of working electrolyzers within the group needs to increase, start the electrolyzers from the right end of the current operation; when the number of working electrolyzers within the group needs to decrease, turn off the electrolyzers from the right of the current operation starting position; 2.4, Rotation method for each group in the ALK group: First, sort the electrolyzer groups from left to right. When the number of working electrolyzer groups needs to increase, start the electrolyzer groups from the right of the last operating one; when the number of working electrolyzer groups needs to decrease, close the electrolyzer groups from the right of the first operating one; 2.5, Critical value for adding or subtracting electrolyzers within the ALK group: When the power P allocated to the electrolyzer group st is greater than the sum of the maximum powers of the currently operating electrolyzers ∑P sgmax , start additional electrolyzers; when the power P allocated to the electrolyzer group st is less than the sum of the minimum powers of the currently operating electrolyzers ∑P sgmin , shut down electrolyzers, and the number of additions or subtractions is determined based on the surplus or deficit power and the operating range of the power of the non-activated electrolyzers; 2.6, Critical values for increasing or decreasing the number of electrolyzer stacks in the ALK group: When the power P for alkaline hydrogen production ALK is greater than the sum of the maximum powers of the currently operating electrolyzer stacks ∑P stmax , start additional electrolyzer stacks; when the power P for alkaline hydrogen production ALK is less than the sum of the minimum powers of the currently operating electrolyzer stacks ∑P stmin , stop the electrolyzer stacks, and determine the number of stacks to be increased or decreased based on the surplus or deficit power and the operating range of the power of the unactivated electrolyzer stacks; 2.7, Start-stop characteristics of the ALK group: Consider when the power P of the ALK group st is greater than or equal to the minimum output P of the ALK group stmin At this time, each electrolyzer in the non-operating state within the group is in a hot standby state, and there is no loss during startup; when the entire ALK group is shut down, each electrolyzer within the group is in a cold standby state, and losses are considered during startup. The loss amount is determined based on the loss coefficient, shutdown time, and temperature before startup; 2.8, Start-up loss of the ALK group: Since it is assumed that each electrolyzer in the ALK group is in the operating or hot standby state during operation, the start-up loss of the ALK electrolyzer only exists during the start-up of the whole group; the start-up loss of the ALK electrolyzer is related to the start-up time, and the start-up time is related to the temperature of the electrolyzer at start-up; Considering the start-up loss of a single ALK group is: P loss = (85 - T t-1 ) / (85 - 20) × P × c Among them, P loss is the start-up loss of the electrolyzer unit; T t-1 is the temperature at the start-up of the electrolyzer unit; P is the electric power after the electrolyzer unit is fully started; c is the loss coefficient, taking 0.

12.

4. A method for optimizing the configuration of a multi-group hydrogen production electrolytic cell according to claim 3, characterized in that, In step 2, it is considered that the electrolyzers in the ALK group preferably adopt the same grouping method. However, when the total number of electrolyzers cannot be divided evenly by the number of electrolyzers in a single group, there will be a situation where the number of electrolyzers in one ALK group is less than that in other groups. Such a group is called an unbalanced group; the calculation method for the operating range of the unbalanced group is the same as that of the balanced group: 0.5P sg ≤P st ≤∑1.1P sgmax The unbalanced group participates in the rotation operation of the ALK group using the same rotation strategy, and only the calculation method is different when considering the critical value for adding a group, that is, the critical value for adding an electrolyzer group is the product of the number of electrolyzers in the unbalanced group and the maximum operating power of a single electrolyzer.

5. A method for optimizing the configuration of a multi-group hydrogen production electrolytic cell according to claim 1, characterized in that, In step 3, the start-stop characteristics include: the rated production capacity of a single PEM, the rated electric power of a single PEM, the operating range of the PEM, the start-up time of the PEM, the start-up loss of the PEM, and the rotation method of the PEM; in the PEM model, there are several PEM electrolyzers, but the PEM electrolyzers operate independently for hydrogen production and do not form groups. Specifically, it includes the following content: 3.1, Rated production capacity of a single cell of a PEM electrolyzer: The rated production capacity of a single cell of a PEM electrolyzer is denoted as C PEM ; 3.2, Rated electric power per unit of PEM electrolyzer: The rated electric power of the PEM electrolyzer is denoted as P PEM0 ; 3.3, Operating range of the PEM electrolyzer: Considering the actual operating power range of the PEM electrolyzer is: 0.1P PEM0 ≤P PEM ≤1.5P PEM0 ; Among them, 0.1P PEM0 is denoted as P PEMmin ; 1.5P PEM0 is denoted as P PEMmax ; 3.4, Start-up time of the PEM electrolyzer: Considering the start-up time of the PEM electrolyzer is 10 minutes; 3.5, Start-up loss of the PEM electrolyzer: Simplify the start-up loss of the PEM model to 12% of the average power during the start-up process; 3.6, Rotation method of the PEM electrolyzer: The operating range of a single PEM electrolyzer is: 0.1P PEM0 ≤P PEM ≤1.5P PEM0 When the electric power used for the PEM electrolyzer exceeds the upper and lower limits of the operating range, perform addition and subtraction operations on the PEM electrolyzer and list the start-up loss.

6. A method for optimizing the configuration of a multi-group hydrogen production electrolytic cell according to claim 1, characterized in that, In step 4, it specifically includes the following steps: 4.1, Combine the current electrolyzer installation situation and grouping situation to determine the critical values for adding and subtracting groups of the PEM model, ALK balanced groups, ALK unbalanced groups, and the critical values for adding and subtracting electrolyzers of a single ALK cell; 4.2, Calculate the change in the injection power P1 of the large model of the current electrolyzer hydrogen production system, and give priority to performing addition and subtraction operations on the PEM electrolyzers in the PEM model to ensure the stable operation of the ALK group as much as possible; 4.3, When the injection power fluctuation exceeds the adjustment ability of the PEM model, calculate the overflow power P2 that the PEM model cannot adjust and allocate it to the ALK group for adjustment; when the injection power fluctuation is less than the adjustment ability of the PEM model, calculate the missing power P3; 4.4, Compare the overflow power P2 or the missing power P3 with the critical values for adding and subtracting groups of the ALK group, and perform operations to increase or decrease the ALK group; 4.5 When it is necessary to increase the ALK group, start the electrolyzer group from the right side of the end of the current operation. When it is necessary to reduce the ALK group, shut down the electrolyzer group from the right side of the first position of the current operation; 4.6 When the operating power of the ALK group changes, compare the power fluctuation value within the group with the critical value of adding or subtracting cells, and consider whether it is necessary to start or shut down the electrolyzer; when it is necessary to add an electrolyzer within the ALK group, start the electrolyzer from the right side of the end of the current operation. When it is necessary to reduce the electrolyzer within the ALK group, shut down the electrolyzer from the right side of the first position of the current operation.

7. A method for optimizing the configuration of a multi-group hydrogen production electrolytic cell according to claim 1, characterized in that, In step 5, the considered indicators are the electro-hydrogen conversion efficiency, the number of ALK starts and stops, and the unit hydrogen production cost. The optimization results can not only ensure economic benefits but also achieve efficient utilization of energy and extend the service life of alkaline hydrogen production equipment; the specific calculation methods for each parameter in the optimization objective are as follows: (1) High efficiency: The efficiency variable of the electrolyzer hydrogen production system is used to judge the electro-hydrogen conversion efficiency of the hydrogen production system, and the calculation formula is: η = E Hp / E inj Among them, E Hp is the electrical energy for effective hydrogen production, and E inj is the electrical energy injected into the electrolyzer hydrogen production system; (2) Stability: The stability variable of the electrolyzer hydrogen production system is characterized by the average number of starts and stops per cell of ALK, K: K = N s / N cell Among them, N s is the number of starts and stops of all ALK electrolyzers throughout the year, and N cell is the number of ALK electrolyzers configured in the hydrogen production system of the electrolyzer; (3) Economy: The economy of the electrolyzer hydrogen production system is characterized by the unit hydrogen production cost; the hydrogen production cost of the electrolyzer hydrogen production system is divided into four parts, including the initial investment cost and operation and maintenance cost of ALK and PEM in the electrolyzer hydrogen production system; the specific calculation formula is: Among them, Cost is the unit hydrogen production cost, C inv1 , C inv2 are the initial investment costs of ALK and PEM respectively, Y1 and Y2 are the system operation lives of ALK and PEM respectively, C mat1 , C mat2 are the operation and maintenance costs of ALK and PEM respectively, A H is the hydrogen production; (4) Comprehensive objective function: In the electrolyzer hydrogen production system, consider the linear combination of three parameters: high efficiency, stability, and economy. After parameter normalization, the weights are selected in combination with engineering experience. The specific combination method is as follows: η is given a coefficient of -2; K is given a coefficient of 3 and divided by 400 to unify the order of magnitude; Cost is given a coefficient of 9 and divided by 1000 to unify the order of magnitude; the final objective function used by the electrolyzer hydrogen production system is: The smaller the objective function, the better the electrolyzer hydrogen production system.

8. A method for optimizing the configuration of a multi-group hydrogen production electrolytic cell according to claim 1, characterized in that, In step 6, the specific process of the sequential traversal method is as follows: Use a double-layer nested loop. The outer loop traverses the number of cells in a single ALK group, taking integers from 1 to 4; the inner loop traverses the total number of ALK cells, taking integers from 1 to the maximum number of cells according to the injection power scale; For each loop, calculate the objective function value of the electrolyzer hydrogen production system and store the parameters corresponding to the minimum objective function so far; If the objective function of the current loop is less than the stored data, update the stored data; after the sequential traversal program runs to completion, output the minimum objective function and the corresponding parameters.

9. A method for optimizing the configuration of a multi-group hydrogen production electrolytic cell according to claim 1, characterized in that In step 7, the process of the optimization configuration specifically includes the following steps: 7.1 Input the parameters of the electro-thermal characteristics of the single ALK cell model, the parameters of the rotation value of the ALK group operation model, the parameters of the start-stop characteristics of the PEM model, the 8760-hour power supply for hydrogen production, the unit investment cost of a single ALK cell, the unit investment cost of the PEM electrolyzer, the ALK operation and maintenance cost, and the PEM operation and maintenance cost; 7.2 Combine the 8760-hour power curve for hydrogen production to calculate the maximum number of ALK electrolyzers and the maximum number of PEM electrolyzers allowed to be installed; 7.3, Calculate the working status of the electrolytic cell for 8760 hours, calculate the operating status of each hour of the ALK group and the PEM electrolytic cell in a rotating shift manner, and the operating status of each electrolytic cell within the ALK group; 7.4, After running the annual data, statistically analyze the electricity-to-hydrogen conversion efficiency, the average start-stop times of each single ALK cell, the unit hydrogen supply cost, and calculate the objective function; 7.5, Apply steps 7.3 and 7.4 to calculate the configuration schemes of all single ALK cells and ALK groups, and select the scheme with the minimum objective function as the recommended scheme.

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