Alkaline water electrolysis hydrogen production control method and system

Abstract

The invention discloses an alkaline water electrolysis hydrogen production control method and system, and relates to the technical field of electrolysis, and the method comprises the following steps: obtaining an alkaline liquid circulation flow demand; according to the flow range of the alkali liquor circulating pump in each circulating branch, a plurality of flow control strategies meeting the alkali liquor circulating flow requirement are determined; determining corresponding power according to the flow of each alkali liquor circulating pump in the flow control strategy; determining a power demand corresponding to each flow control strategy; optimizing a flow control strategy by taking the minimum power demand as a target; and controlling a circulation branch by using the optimized flow control strategy. According to the method, after the multiple flow control strategies are obtained, the corresponding target function is established, the target function is optimized with the minimum power requirement as the target, the flow control strategy with the minimum power and meeting the alkali liquor circulation flow requirement is obtained, and the total power of the alkali liquor circulation pump in the alkali liquor circulation process can be effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrolysis, in particular to a control method and system for hydrogen production by alkaline electrolysis of water. BACKGROUND

[0002] Hydrogen is an important industrial raw material, and its preparation methods mainly include three types: petroleum preparation, industrial by-product preparation, and water electrolysis. The first two are relatively traditional preparation methods, which consume non-renewable resources, while water electrolysis for hydrogen production completely utilizes renewable resources, has the advantages of environmental friendliness and sustainable development.

[0003] In water electrolysis for hydrogen production, the most commonly used method is to electrolyze alkaline solution. By applying a voltage to the alkaline solution and performing gas-liquid separation on the mixture of alkaline solution and hydrogen and oxygen, hydrogen can be prepared with high efficiency. In the preparation process, not only is the consumed alkaline solution replenished into the electrolytic tank, but also the alkaline solution is circulated and heat exchanged to reduce the temperature during circulation to ensure that the electrolytic tank can work normally and efficiently. For example, CN111826670A discloses a combined alkaline solution circulation device, an alkaline water electrolysis hydrogen production system, and a control method. It uses multiple parallel alkaline solution circulation branches to start different branches to meet the circulation demand when the circulation power demand is different.

[0004] However, although the above patent controls the operating state of each branch according to the circulation flow demand, it only considers the matching of the demand flow and the actual flow, and does not consider the power influence of the alkaline solution circulating pump. Since electrolysis is a high-energy-consuming industry, low-energy-consumption production has always been the goal of the industry development. The above patent does not consider the power of the alkaline solution circulating pump, so it is not conducive to reducing the energy consumption in the entire production process. SUMMARY

[0005] The embodiments of the present application provide a control method and system for hydrogen production by alkaline electrolysis of water to solve the problem of high energy consumption caused by not considering the power of the alkaline solution circulating pump in the prior art.

[0006] In one aspect, the embodiments of the present application provide a control method for hydrogen production by alkaline electrolysis of water, comprising:

[0007] obtaining an alkaline solution circulation flow demand;

[0008] determining a plurality of flow control strategies that meet the alkaline solution circulation flow demand according to the flow range of the alkaline solution circulating pump in each circulation branch;

[0009] determining the corresponding power of each alkaline solution circulating pump in the flow control strategy;

[0010] determining the power demand corresponding to each flow control strategy;

[0011] Optimize the flow control strategy with the minimum power demand as the target;

[0012] Control the circulation branch by using the optimized flow control strategy.

[0013] In another aspect, the embodiment of the present application also provides a hydrogen production control system by alkaline electrolysis of water, comprising:

[0014] The data processing unit is configured to obtain the caustic solution circulation flow demand, determine a plurality of flow control strategies meeting the caustic solution circulation flow demand according to the flow range of the caustic solution circulation pump in each circulation branch, determine the power of each caustic solution circulation pump according to the flow in the flow control strategy, determine the power demand corresponding to each flow control strategy, and optimize the flow control strategy with the minimum power demand as the target.

[0015] The caustic solution circulation pump is configured to control the circulation branch by using the optimized flow control strategy.

[0016] The hydrogen production control method and system by alkaline electrolysis of water in the present application have the following advantages:

[0017] After obtaining the plurality of flow control strategies, the corresponding objective functions are established, and the objective functions are optimized with the minimum power demand as the target to obtain the flow control strategy with the minimum power and meeting the caustic solution circulation flow demand, which can effectively reduce the total power of the caustic solution circulation pump in the caustic solution circulation process. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0019] Figure 1 A flow chart of the hydrogen production control method by alkaline electrolysis of water provided by the embodiment of the present application. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0021] Figure 1A flow chart of a hydrogen production control method by alkaline electrolysis of water is provided for the embodiments of the present application. The embodiments of the present application provide a hydrogen production control method by alkaline electrolysis of water, comprising:

[0022] S100, obtaining an alkaline solution circulation flow demand.

[0023] Exemplarily, while the alkaline solution participates in electrolysis in the electrolytic cell, it also needs to be heat-exchanged with the heat exchange system by using the alkaline solution circulating pump, so that the heat generated by the alkaline solution in the electrolysis process is taken away by the heat exchange system, achieving the purpose of cooling the alkaline solution. The alkaline solution after temperature reduction will continue to return to the electrolytic cell to continue to participate in electrolysis.

[0024] The alkaline solution circulation flow demand in the embodiments of the present application is to ensure the flow rate of the alkaline solution when circulating in the electrolytic cell at a certain temperature. The temperature can be the maximum temperature allowed for stable and efficient operation of the electrolytic cell, or a temperature set by the operator. Of course, the temperature set by the operator cannot be higher than the maximum temperature allowed for the electrolytic cell. When the actual flow rate reaches the flow demand, the temperature of the alkaline solution in the electrolytic cell can be maintained at the required temperature or below and remain relatively stable. Therefore, when determining the appropriate flow demand, the current temperature, target temperature, and temperature rise speed of the alkaline solution in the electrolytic cell need to be determined first, and then the corresponding flow demand is determined according to these data. It should be understood that the determined flow demand can not be a constant value. For example, when the current temperature exceeds the target temperature, the alkaline solution needs to be rapidly cooled at a larger flow rate. When the current temperature of the alkaline solution is reduced to the target temperature or below, the alkaline solution is maintained at a smaller flow rate.

[0025] S110, determining a plurality of flow control strategies satisfying the alkaline solution circulation flow demand according to the flow range of the alkaline solution circulating pump in each circulation branch.

[0026] Exemplarily, each circulation branch has an alkaline solution circulating pump, and the plurality of alkaline solution circulating pumps have different flow ranges. The flow range of the i th alkaline solution circulating pump is: imin ≤F i ≤F imax Therefore, the flow control strategy composed of the flow rates of the plurality of alkaline solution circulating pumps can be expressed as:

[0027] F=[F1,F2,...F i ,...F N ]

[0028] s.t:

[0029] F imin ≤F i ≤F imax

[0030] Wherein, N is the total number of lye circulating pumps.

[0031] The above flow control strategy forms a sequence of target flow of multiple lye circulating pumps, under each flow control strategy, the lye circulating flow demand should be met, that is:

[0032]

[0033] Wherein, F need represents the lye circulating flow demand.

[0034] S120, according to the flow of each lye circulating pump in the flow control strategy, the corresponding power is determined.

[0035] Exemplarily, the flow of the lye circulating pump is determined by the input power, and the flow and power are in a positive proportional relationship, that is, the greater the power, the greater the flow, and there is a one-to-one correspondence between the power and the flow. Therefore, after the flow control strategy is determined, the flow of each lye circulating pump is also known, and the corresponding power can be uniquely determined according to the corresponding relationship between the flow and the power.

[0036] Because the lye circulating pumps in the embodiments of the present application have different flow ranges, the models of the lye circulating pumps are also different, and different models of lye circulating pumps have different power and flow corresponding relationships. In order to ensure that the accurate power can be determined according to the flow, the present application further calibrates each lye circulating pump before determining the power of each lye circulating pump, in order to determine the relationship between the power and the flow of the lye circulating pump. In the calibration process, the lye circulating pump can be input with multiple different powers in advance, and then the output flow is detected. After measuring multiple power-flow data, a method such as least squares method can be used to fit the power-flow data to obtain the corresponding curve. The curve is the relationship curve of power and flow.

[0037] S130, determine the power demand corresponding to each flow control strategy.

[0038] Exemplarily, after determining the power of each lye circulating pump in a flow control strategy, the sum of the powers of all lye circulating pumps can obtain the power demand of each flow control strategy:

[0039]

[0040] Wherein, P jneed is the power demand of the jth flow control strategy, P ij is the power of the ith lye circulating pump in the jth flow control strategy.

[0041] S140, optimize the flow control strategy with the minimum power demand as the target.

[0042] Exemplarily, after determining the power requirement of each flow control strategy at S130, a target function in the present application can be determined, which aims to minimize the power requirement of each flow control strategy:

[0043] G = min(P 1need ,P 2need ,...,P jneed ,...,P Mneed )

[0044] Wherein, M is the total number of flow control strategies.

[0045] In the embodiments of the present application, when optimizing the flow control strategy aiming to minimize the power requirement, the power requirement and the sum of power variation are combined to form a combined target function, and the flow control strategy is optimized aiming to minimize the combined target function.

[0046] After using the target function aiming to minimize the power requirement, there may be some caustic soda circulating pumps that need to change greatly on the basis of the current power, i.e. increase or decrease a large power amplitude, in order to reach the target power in the flow control strategy, in order to achieve the required target flow. This control mode exists the behavior of sudden acceleration or sudden deceleration of the caustic soda circulating pump, and unnecessary energy needs to be consumed in the process of such sharp change in speed. Therefore, in order to reduce this part of energy consumption, the sum of power variation and power requirement are combined to form a combined target function, and then the flow control strategy is optimized based on the combined target function:

[0047] G' = min(P 1need +δ1,P 2need +δ2,...,P jneed +δ j ,...,P Mneed +δ M )

[0048] Wherein, δ j represents the sum of power variation of the jth flow control strategy:

[0049]

[0050] Wherein, P nij represents the current power of the ith caustic soda circulating pump in the jth flow control strategy, and P tij represents the target power of the ith caustic soda circulating pump in the jth flow control strategy.

[0051] Obviously, before the sum of power requirements and power variation amounts is combined, the difference between the target power and the current power in each flow control strategy is also determined, and the sum of power differences of multiple flow control strategies is taken as the sum of power variation amounts.

[0052] In the optimization process, a genetic simulated annealing algorithm can be used to optimize the flow control strategy. Specifically, the genetic simulated annealing algorithm includes coding operation, initialization, fitness function, selection operation, crossover operation and mutation operation in turn.

[0053] After the flow control strategy is optimized, a flow control strategy that meets the caustic soda circulation flow requirement and has the minimum sum of power requirements and power variation amounts can be obtained, which is the optimal control strategy for the alkaline electrolysis water hydrogen production system under the current state. It should be understood that since the caustic soda circulation flow requirement can not be a fixed value, when this situation occurs, the generated optimal flow control strategy should also be a plurality of flow sequences sorted over time.

[0054] S150, controlling the circulation branch by using the optimized flow control strategy.

[0055] Exemplarily, after the above optimal flow control strategy is obtained, each corresponding caustic soda circulation pump can be controlled by using the optimal control strategy, so that each caustic soda circulation pump works according to the optimal control strategy, achieving the best caustic soda circulation control purpose.

[0056] In the embodiments of the present application, the output flow of each caustic soda circulation pump can also be monitored to determine whether the real-time flow of the caustic soda circulation pump is the same as the flow in the optimal control strategy. If not, the power of the caustic soda circulation pump needs to be adjusted in time to make its flow meet the requirements of the optimal control strategy.

[0057] The embodiments of the present application also provide an alkaline electrolysis water hydrogen production control system, which comprises:

[0058] The data processing unit is configured to obtain a caustic soda circulation flow requirement, determine a plurality of flow control strategies meeting the caustic soda circulation flow requirement according to the flow range of the caustic soda circulation pump in each circulation branch, determine the corresponding power of each caustic soda circulation pump in the flow control strategy, determine the power requirement corresponding to each flow control strategy, and optimize the flow control strategy with the minimum power requirement as the target.

[0059] The caustic soda circulation pump is configured to control the circulation branch by using the optimized flow control strategy.

[0060] While the preferred embodiments of the application have been described, additional variations and modifications can be made to these embodiments by those skilled in the art once they have the benefit of the present disclosure without departing from the spirit and scope of the application. Accordingly, it is intended that such additions and modifications be included within the scope of the application. It is the following claims, including any amendments thereto, which define the scope of the application.

[0061] Obviously, numerous modifications and variations of the present application are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A method for controlling hydrogen production by alkaline water electrolysis, characterized in that: include: Obtain alkali solution circulation flow demand; Determining a plurality of flow control strategies that meet the alkali solution circulation flow demand according to the flow range of the alkali solution circulation pump in each circulation branch; Determining the corresponding power according to the flow rate of each alkali solution circulation pump in the flow control strategy; determining a power requirement corresponding to each of the flow control strategies; Optimizing the flow control strategy with the goal of minimizing the power demand; The circulation branch is controlled using the optimized flow control strategy.

2. A method for controlling hydrogen production by alkaline water electrolysis according to claim 1, characterized in that: Before determining the power of each of the alkali liquid circulation pumps, each of the alkali liquid circulation pumps is calibrated to determine the relationship between the power and flow rate of the alkali liquid circulation pump.

3. The method for controlling hydrogen production by alkaline water electrolysis according to claim 1, wherein: When optimizing the flow control strategy with the goal of minimizing the power demand, the power demand and the sum of the power variation are combined to form a combined objective function, and the flow control strategy is optimized with the goal of minimizing the combined objective function.

4. A method for controlling hydrogen production by alkaline water electrolysis according to claim 1 or 3, characterized in that: The flow control strategy is optimized using a genetic simulated annealing algorithm.

5. A method for controlling hydrogen production by alkaline water electrolysis according to claim 4, characterized in that: The genetic simulated annealing algorithm includes encoding operation, initialization, fitness function, selection operation, crossover operation and mutation operation which are performed in sequence.

6. The method for controlling hydrogen production by alkaline water electrolysis according to claim 3, wherein: Before combining the power demand and the sum of the power variations, the difference between the target power and the current power in each flow control strategy is determined, and the sum of the power differences of the multiple flow control strategies is used as the sum of the power variations.

7. An alkaline water electrolysis hydrogen production control system, characterized in that: include: a data processing unit, configured to obtain a caustic soda circulation flow demand, determine a plurality of flow control strategies that meet the caustic soda circulation flow demand based on a flow range of a caustic soda circulation pump in each circulation branch, determine a corresponding power based on the flow rate of each caustic soda circulation pump in the flow control strategy, determine a power demand corresponding to each of the flow control strategies, and optimize the flow control strategies with the goal of minimizing the power demand; The alkali solution circulation pump is used to control the circulation branch using the optimized flow control strategy.

8. The alkaline water electrolysis hydrogen production control system according to claim 7, characterized in that: Each of the circulation branches is provided with an alkali solution circulation pump, and the multiple alkali solution circulation pumps have different flow ranges.

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