Electrolytic bath pressure difference control device and method in alkaline electrolytic hydrogen production system

Abstract

The invention provides an electrolytic bath pressure difference control device and method in an alkaline electrolytic hydrogen production system, and the device comprises a first pressure difference measurement part which detects the inlet pressure difference between the oxygen side and the hydrogen side of an electrolytic bath; the second pressure difference measuring part is used for detecting the outlet pressure difference between the oxygen side and the hydrogen side of the electrolytic bath; the first regulating valve is arranged at a hydrogen side inlet or an oxygen side inlet of the electrolytic cell; the second regulating valve is arranged at a hydrogen side outlet or an oxygen side outlet of the electrolytic bath; the controller receives the inlet pressure difference and the outlet pressure difference and adjusts the first adjusting valve and / or the second adjusting valve according to the inlet pressure difference and the outlet pressure difference, so that the inlet pressure value of the oxygen side is larger than or equal to the inlet pressure value of the hydrogen side, and the inlet pressure difference of the oxygen side and the hydrogen side is kept within a first set range. The outlet pressure value of the oxygen side is larger than or equal to the outlet pressure value of the hydrogen side, and the outlet pressure difference of the oxygen side and the hydrogen side is kept within a second set range. According to the scheme, the precision of pressure control of the electrolytic cell is improved.

Description

Technical Field

[0001] This application relates to the field of water electrolysis for hydrogen production technology, specifically to a device and method for controlling the differential pressure of an electrolyzer in an alkaline water electrolysis hydrogen production system. Background Technology

[0002] In alkaline water electrolysis hydrogen production systems, to achieve the goal of pressure balance on the oxygen side of the electrolyzer, the liquid level balance of the gas-liquid separator is typically controlled. As disclosed in patent document CN 202211660852.4, the real-time pressure and pressure difference at the hydrogen and oxygen outlets of the electrolyzer are obtained. Then, based on the pressure and pressure difference on the hydrogen and oxygen sides, the changing trend of hydrogen content in the oxygen within the electrolyzer is obtained, and the pressure on the hydrogen and / or oxygen sides is adjusted accordingly.

[0003] In the aforementioned prior art documents, the first pressure regulating valve and the second pressure regulating valve are respectively installed at the oxygen-side outlet and the hydrogen-side outlet of the electrolyzer. Hydrogen-side pressure gauges and oxygen-side pressure gauges are respectively installed on the oxygen-side and hydrogen-side of the electrolyzer. The first pressure regulating valve is used to regulate the oxygen-side pressure, and the second pressure regulating valve is used to regulate the hydrogen-side pressure. The hydrogen-side pressure gauge collects the pressure on the hydrogen-side of the electrolyzer, and the oxygen-side pressure gauge collects the pressure on the oxygen-side of the electrolyzer. A differential pressure transmitter collects the pressure difference between the hydrogen-side and oxygen-side of the electrolyzer. A controller receives the pressure difference collected by the differential pressure transmitter, the hydrogen-side pressure collected by the hydrogen-side pressure gauge, and the oxygen-side pressure collected by the oxygen-side pressure gauge. Based on the pressure and pressure difference on the hydrogen-side and oxygen-side of the electrolyzer, the controller obtains the changing trend of the hydrogen content in the oxygen within the electrolyzer, and controls the first pressure regulating valve and / or the second pressure regulating valve to regulate the pressure on the hydrogen-side and / or oxygen-side. In practical applications, the pipe diameter, length, and materials of the pipelines from the electrolyzer to the gas-liquid separator on both the hydrogen and oxygen sides are fixed, while the fluid properties on both sides fluctuate with the load. Under different loads, the pressure drop on the hydrogen and oxygen sides of the pipelines from the electrolyzer outlet to the gas-liquid separator varies. The electrolyzer consists of several individual electrolytic cells, and the different gas production rates (twice that of the oxygen side) in the anion oxygen side chambers of each individual cell lead to different pressure drops on the hydrogen and oxygen sides. Furthermore, inconsistencies may exist between the individual cells due to design and manufacturing deviations, all of which can cause different pressure drops on the hydrogen and oxygen side chambers. Relying solely on pressure gauges at the hydrogen and oxygen outlets of the electrolyzer to measure pressure and differential pressure to obtain the trend of hydrogen content changes in the oxygen within the electrolyzer will introduce errors, making it inaccurate to use this as a reference for adjusting the system's regulating valves. Summary of the Invention

[0004] The technical problem this application aims to solve is that the existing method of adjusting the pressure values ​​on both the hydrogen and oxygen sides of the electrolyzer based solely on the outlet pressure and differential pressure value of the electrolyzer has errors. Therefore, this application provides an electrolyzer differential pressure control device and method in an alkaline electrolysis hydrogen production system.

[0005] In a first aspect, the technical solution of this application provides a differential pressure control device for an electrolyzer in an alkaline electrolysis hydrogen production system, comprising:

[0006] The first differential pressure measuring component is used to detect the inlet pressure difference between the oxygen side and the hydrogen side of the electrolyzer;

[0007] The second differential pressure measuring component is used to detect the outlet pressure difference between the oxygen side and the hydrogen side of the electrolyzer;

[0008] The first regulating valve is located at the hydrogen-side inlet or the oxygen-side inlet of the electrolytic cell;

[0009] The second regulating valve is located at the hydrogen-side outlet or the oxygen-side outlet of the electrolyzer.

[0010] The controller receives the inlet pressure difference sent by the first differential pressure measuring component and the outlet pressure difference sent by the second differential pressure measuring component, and adjusts the first regulating valve and / or the second regulating valve according to the inlet pressure difference and the outlet pressure difference, so that:

[0011] The inlet pressure value of the oxygen side is greater than or equal to the inlet pressure value of the hydrogen side, and the inlet pressure difference between the oxygen side and the hydrogen side is maintained within a first set range.

[0012] The outlet pressure value of the oxygen side is greater than or equal to the outlet pressure value of the hydrogen side, and the outlet pressure difference between the oxygen side and the hydrogen side is maintained within a second set range.

[0013] The differential pressure control device for the electrolyzer in some of the alkaline electrolysis hydrogen production systems also includes:

[0014] The third regulating valve is respectively located at the hydrogen-side inlet and the oxygen-side inlet of the electrolytic cell, along with the first regulating valve.

[0015] The fourth regulating valve, along with the second regulating valve, is respectively located at the hydrogen-side outlet and the oxygen-side outlet of the electrolytic cell;

[0016] The controller adjusts at least one of the first regulating valve, the second regulating valve, the third regulating valve, and the fourth regulating valve according to the inlet pressure difference and the outlet pressure difference, so that:

[0017] The inlet pressure value of the oxygen side is greater than or equal to the inlet pressure value of the hydrogen side, and the inlet pressure difference between the oxygen side and the hydrogen side is maintained within a first set range.

[0018] The outlet pressure value of the oxygen side is greater than or equal to the outlet pressure value of the hydrogen side, and the outlet pressure difference between the oxygen side and the hydrogen side is maintained within a second set range.

[0019] In some solutions, the differential pressure control device for the electrolyzer in the alkaline electrolysis hydrogen production system includes a differential pressure transmitter as the first differential pressure measuring component. The two ends of the differential pressure transmitter are respectively connected to the oxygen-side inlet and the hydrogen-side inlet of the electrolyzer. The differential pressure transmitter measures the inlet pressure difference.

[0020] In some solutions, the differential pressure control device for the electrolyzer in an alkaline electrolysis hydrogen production system includes a first differential pressure measuring component comprising a pair of pressure sensors and a calculation unit;

[0021] The pair of pressure sensors are respectively installed at the oxygen-side inlet and the hydrogen-side inlet of the electrolytic cell, and are used to detect the oxygen-side inlet pressure value and the hydrogen-side inlet pressure value of the electrolytic cell.

[0022] The calculation unit receives the oxygen-side inlet pressure value and the hydrogen-side inlet pressure value and calculates the inlet pressure difference.

[0023] In some solutions, the differential pressure control device for the electrolyzer in the alkaline electrolysis hydrogen production system has the first regulating valve and the third regulating valve both located upstream of the first differential pressure measuring component, between the first differential pressure measuring component and the circulating pump.

[0024] In some schemes, the differential pressure control device for the electrolyzer in the alkaline electrolysis hydrogen production system includes a second regulating valve located between the second differential pressure measuring component and the oxygen-side gas-liquid separator.

[0025] The fourth regulating valve is located between the second differential pressure measuring component and the hydrogen-side gas-liquid separator.

[0026] The differential pressure control device for the electrolyzer in some of the alkaline electrolysis hydrogen production systems also includes:

[0027] A pressure regulating valve is provided at the outlet of the oxygen-side gas-liquid separator connected to the oxygen-side outlet of the electrolyzer, and at the outlet of the hydrogen-side gas-liquid separator connected to the hydrogen-side outlet of the electrolyzer.

[0028] Secondly, the technical solution of this application provides a method for controlling the differential pressure of an electrolyzer in an alkaline electrolysis hydrogen production system, including:

[0029] The inlet pressure difference between the oxygen side and the hydrogen side of the electrolyzer is obtained. If the inlet pressure difference is not within a first set range, the inlet pressure value of the oxygen side or the hydrogen side is adjusted until the inlet pressure difference is maintained within the first set range.

[0030] The outlet pressure difference between the oxygen side and the hydrogen side of the electrolyzer is obtained. If the outlet pressure difference is not within a second set range, the outlet pressure value of the oxygen side or the hydrogen side is adjusted until the outlet pressure difference is maintained within the second set range.

[0031] In some solutions, the electrolyzer pressure differential control method in the alkaline electrolysis hydrogen production system has the following settings: the first setting range is 0-100 Pa, and the inlet pressure value of the oxygen side is greater than or equal to the inlet pressure value of the hydrogen side; the second setting range is 0-200 Pa, and the outlet pressure value of the oxygen side is greater than or equal to the outlet pressure value of the hydrogen side.

[0032] In some solutions for alkaline electrolytic hydrogen production systems, the differential pressure control method for the electrolyzer involves the following: If a first or third regulating valve is installed at the oxygen inlet side of the electrolyzer, increasing the opening of the first or third regulating valve increases the oxygen pressure value of the electrolyzer; decreasing the opening of the first or third regulating valve decreases the oxygen pressure value of the electrolyzer. Similarly, if a second or fourth regulating valve is installed at the oxygen outlet side of the electrolyzer, increasing the opening of the second or fourth regulating valve decreases the oxygen pressure value of the electrolyzer; decreasing the opening of the second or fourth regulating valve increases the oxygen pressure value of the electrolyzer.

[0033] If a first or third regulating valve is provided on the hydrogen inlet side of the electrolyzer, then increasing the opening of the first or third regulating valve will cause the hydrogen-side pressure of the electrolyzer to increase; decreasing the opening of the first or third regulating valve will cause the hydrogen-side pressure of the electrolyzer to decrease. If a second or fourth regulating valve is provided on the hydrogen outlet side of the electrolyzer, then increasing the opening of the second or fourth regulating valve will cause the hydrogen-side pressure of the electrolyzer to decrease; decreasing the opening of the second or fourth regulating valve will cause the hydrogen-side pressure of the electrolyzer to increase.

[0034] The technical solution provided in this application has at least the following technical effects compared with the prior art:

[0035] The electrolytic cell differential pressure control device and method in the alkaline electrolytic hydrogen production system provided in this application include a first differential pressure measuring component for measuring the inlet pressure difference at the oxygen-side outlet and the hydrogen-side inlet of the electrolytic cell, and a second differential pressure measuring component for measuring the outlet pressure difference at the oxygen-side outlet and the hydrogen-side outlet of the electrolytic cell. The first and second regulating valves can be used to regulate the inlet and outlet flow rates on the oxygen and / or hydrogen sides, thereby adjusting the pressure difference on the oxygen or hydrogen sides. The controller controls the first and / or second regulating valves based on the relationship between the inlet pressure difference and a first set range, and the relationship between the outlet pressure difference and a second set range. The solution proposed in this application, in addition to relying on the pressure detection results of the oxygen and hydrogen side outlets of the electrolyzer, also needs to refer to the pressure detection results of the oxygen and hydrogen side inlets of the electrolyzer. When controlling the first regulating valve and the second regulating valve, the relationship between the pressure difference between the oxygen and hydrogen side inlets and the pressure difference between the oxygen and hydrogen side outlets is ensured. This eliminates the influence of the flow of the pipeline medium between the oxygen and hydrogen sides and the gas-liquid separator, as well as the influence of the gas pressure inside the oxygen and hydrogen sides, thereby improving the accuracy of the electrolyzer pressure control. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the differential pressure control device of the electrolyzer in an alkaline electrolysis hydrogen production system according to an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of the differential pressure control device of the electrolyzer in an alkaline electrolysis hydrogen production system according to an embodiment of the present invention;

[0038] Figure 3a and Figure 3b These are pressure control strategy curves for the oxygen and hydrogen sides under different load conditions in practical applications.

[0039] Figure 4 This is a flowchart of a method for controlling the differential pressure of an electrolyzer in an alkaline electrolysis hydrogen production system according to one embodiment of this application. Detailed Implementation

[0040] The specific embodiments of this application will be further described below with reference to the accompanying drawings.

[0041] It is readily understood that, based on the technical solution of this application, various structural and implementation methods can be interchanged by those skilled in the art without altering the essential spirit of this application. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this application and should not be considered as the entirety of this application or as limitations or restrictions on the technical solution of the application.

[0042] The directional terms such as up, down, left, right, front, back, front, back, top, and bottom mentioned or possibly used in this specification are defined relative to the structures shown in the accompanying drawings. They are relative concepts and may therefore vary depending on their location and usage. Therefore, these or other directional terms should not be interpreted as restrictive.

[0043] like Figure 1 As shown, in an alkaline water electrolysis hydrogen production system, to achieve the goal of pressure balance on the oxygen side of the electrolyzer, the liquid level balance of the gas-liquid separator is usually controlled. Therefore, the alkaline water electrolysis hydrogen production system includes an electrolyzer 10 (the anode side corresponds to the oxygen side, and the cathode side corresponds to the hydrogen side), an oxygen-side gas-liquid separator 20, a hydrogen-side gas-liquid separator 30, and a circulating pump 40. A pressure balancing pipe is connected between the oxygen-side gas-liquid separator 20 and the hydrogen-side gas-liquid separator 30. The electrolyzer differential pressure control device in the alkaline electrolysis hydrogen production system provided in this application includes:

[0044] The first differential pressure measuring component dp1 is used to detect the inlet pressure difference between the oxygen side and the hydrogen side of the electrolyzer, that is, to detect the pressure difference between points A0 and B0; the second differential pressure measuring component dp2 is used to detect the outlet pressure difference between the oxygen side and the hydrogen side of the electrolyzer, that is, to detect the pressure difference between points A1 and B1; the first regulating valve 11 is installed at the hydrogen side inlet or the oxygen side inlet of the electrolyzer. Figure 1 The first regulating valve 11 is located at the oxygen inlet, and the second regulating valve 12 is located at the hydrogen outlet or oxygen outlet of the electrolyzer (located at the oxygen outlet in the figure); or, respectively located at the hydrogen inlet (A0) and hydrogen outlet (A1) of the electrolyzer; the controller, which can be a control module with a processor chip, receives the inlet pressure difference sent by the first differential pressure measuring component dp1 and the outlet pressure difference sent by the second differential pressure measuring component dp2, and adjusts the first regulating valve 11 and the second regulating valve 12 according to the inlet pressure difference and the outlet pressure difference, so that the inlet pressure value of the oxygen side is greater than or equal to the inlet pressure value of the hydrogen side, and the inlet pressure difference between the oxygen side and the hydrogen side is maintained within a first set range; the outlet pressure value of the oxygen side is greater than or equal to the outlet pressure value of the hydrogen side, and the outlet pressure difference between the oxygen side and the hydrogen side is maintained within a second set range. The first regulating valve 11 and the second regulating valve 12 can be implemented using flow regulating valves.

[0045] The solution provided in this application includes a first differential pressure measuring component dp1 for measuring the inlet pressure difference at the oxygen-side outlet and the hydrogen-side inlet of the electrolyzer 10, and a second differential pressure measuring component dp2 for measuring the outlet pressure difference at the oxygen-side outlet and the hydrogen-side outlet of the electrolyzer 10. The first regulating valve 11 and the second regulating valve 12 can be used to regulate the inlet and outlet flow rates on the oxygen and / or hydrogen sides, thereby adjusting the pressure difference on the oxygen or hydrogen sides. The controller controls the first regulating valve 11 and / or the second regulating valve 12 based on the relationship between the inlet pressure difference and a first set range, and the relationship between the outlet pressure difference and a second set range. The above scheme, in addition to relying on the pressure detection results of the oxygen and hydrogen side outlets of the electrolyzer, also needs to refer to the pressure detection results of the oxygen and hydrogen side inlets of the electrolyzer. When controlling the first regulating valve 11 and the second regulating valve 12, it is necessary to simultaneously ensure the relationship between the pressure difference between the oxygen and hydrogen side inlets and the pressure difference between the oxygen and hydrogen side outlets. This eliminates the influence of the flow of the pipeline medium between the oxygen and hydrogen sides and the gas-liquid separator, as well as the influence of the gas pressure inside the oxygen and hydrogen sides, thereby improving the accuracy of the electrolyzer pressure control.

[0046] More preferably, such as Figure 2 As shown, it also includes:

[0047] A third regulating valve 111 is respectively disposed at the hydrogen-side inlet and the oxygen-side inlet of the electrolytic cell 10, as shown in the figure. The first regulating valve 11 is disposed at the oxygen-side inlet, and the third regulating valve 111 is disposed at the hydrogen-side inlet. A fourth regulating valve 121 is respectively disposed at the hydrogen-side outlet and the oxygen-side outlet of the electrolytic cell 10, as shown in the figure. The second regulating valve 12 is disposed at the oxygen-side outlet, and the fourth regulating valve 121 is disposed at the hydrogen-side outlet. The controller adjusts at least one of the first regulating valve 11, the second regulating valve 12, the third regulating valve 111, and the fourth regulating valve 121 according to the inlet pressure difference and the outlet pressure difference, such that: the inlet pressure value of the oxygen side is greater than or equal to the inlet pressure value of the hydrogen side, and the inlet pressure difference between the oxygen side and the hydrogen side is maintained within a first set range; the outlet pressure value of the oxygen side is greater than or equal to the outlet pressure value of the hydrogen side, and the outlet pressure difference between the oxygen side and the hydrogen side is maintained within a second set range.

[0048] In the specific adjustment process, adjusting the inlet regulating valve may affect the outlet pressure difference. For example, adjusting the first regulating valve 11 and the third regulating valve 111 changes the inlet pressure difference and may also affect the outlet pressure difference. In this case, it may be necessary to adjust the second regulating valve 12 or the fourth regulating valve 121. After adjusting the second regulating valve 12 or the fourth regulating valve 121, the inlet pressure difference may change again. In this case, the first regulating valve 11 and the third regulating valve 111 should be adjusted again. The above adjustment process may need to be repeated multiple times until the inlet and outlet pressure differences meet the requirements. By setting four regulating valves, the situation where the opening of a certain regulating valve cannot be further adjusted after it is adjusted to the limit value (such as the maximum value) can be avoided. At this time, the inlet and outlet pressure differences can be adjusted by changing the opening of other regulating valves, thereby further ensuring the accuracy of the electrolyzer pressure control.

[0049] like Figure 3a and Figure 3b As shown, the pressure control strategies for maintaining pressure balance (1.8 MPa) in the separator gas space under different load conditions are presented in the existing scheme, including the pressure control strategies on the oxygen and hydrogen sides of the electrolyzer. Figure 3a The local resistance coefficients of the hydrogen side and oxygen side of the electrolyzer and the pipeline were set to 4.0, and the pressure difference between the hydrogen and oxygen sides under different loads ranged from 1936 to 29000 Pa. Figure 3bThe local resistance coefficients for the hydrogen and oxygen sides of the electrolyzer and its pipelines were set to 2.0, and the pressure difference between the hydrogen and oxygen sides ranged from 888 to 16012 Pa under different loads. Based on the simulation results and the set conditions, it was found that the higher the load, the greater the pressure difference between the hydrogen and oxygen sides, and the smaller the local resistance coefficient, the smaller the pressure difference between the hydrogen and oxygen sides. If only the output pressure of the electrolyzer is controlled to meet the requirements, as shown in the figure, although the gas space pressure of the gas-liquid separator is controlled at the same value, the pressure difference between the hydrogen and oxygen side chambers still varies with the load. However, using the above-mentioned scheme of this application, a first differential pressure measuring component dp1 is installed at the oxygen side outlet and hydrogen side inlet of the electrolyzer 10 to measure the inlet pressure difference, and a second differential pressure measuring component dp2 is installed at the oxygen side outlet and hydrogen side outlet of the electrolyzer 10 to measure the outlet pressure difference. The first regulating valve 11 and the third regulating valve 111 can be used to regulate the inlet flow rate of the oxygen side and / or the oxygen side, thereby adjusting the pressure difference at the inlet of the oxygen side or the hydrogen side; the second regulating valve 12 and the fourth regulating valve 121 can be used to regulate the outlet pressure of the oxygen side and / or the oxygen side, thereby adjusting the pressure difference at the outlet of the oxygen side or the hydrogen side. The controller adjusts the first regulating valve 11, the third regulating valve 111, the second regulating valve 12, and the fourth regulating valve 121 according to the relationship between the inlet pressure difference and the first set range, and the relationship between the outlet pressure difference and the second set range, thereby eliminating the influence of the pipeline medium flow between the oxygen side and the hydrogen side and the gas-liquid separator, the influence of the gas pressure in the oxygen side and the hydrogen side, etc., and improving the accuracy of the electrolyzer pressure control.

[0050] In some solutions for alkaline electrolytic hydrogen production systems, the differential pressure control device for the electrolyzer uses a differential pressure transmitter as the first differential pressure measuring component dp1, as shown in the figure. The two ends of the differential pressure transmitter dp1 are connected to the oxygen-side inlet and the hydrogen-side inlet of the electrolyzer 10, respectively. The differential pressure transmitter measures the inlet pressure difference. Since the differential pressure transmitter measures the pressure difference across its two ends, this solution allows for the direct measurement of the inlet pressure difference using a single component.

[0051] As another implementation, in some solutions, the differential pressure control device of the electrolyzer in the alkaline electrolysis hydrogen production system includes a first differential pressure measuring component dp1 that may include a pair of pressure sensors and a calculation unit. The pair of pressure sensors are respectively located at the oxygen-side inlet and the hydrogen-side inlet of the electrolyzer 10, and are used to detect the oxygen-side inlet pressure and the hydrogen-side inlet pressure of the electrolyzer 10. The calculation unit receives the oxygen-side inlet pressure and the hydrogen-side inlet pressure and calculates the inlet pressure difference. Through this application, the inlet pressure difference can be measured using two pressure sensors, and the pressure values ​​of the oxygen-side inlet and the hydrogen-side inlet can also be measured for pressure monitoring of the oxygen-side inlet and the hydrogen-side inlet.

[0052] Preferably, in some schemes, such as Figure 2 As shown, in the differential pressure control device of the electrolyzer in the alkaline electrolysis hydrogen production system, both the first regulating valve 11 and the third regulating valve 111 are located upstream of the first differential pressure measuring component, between the first differential pressure measuring component dp1 and the circulating pump 40. Thus, the first differential pressure measuring component dp1 can directly measure the pressure difference between the oxygen-side inlet and the hydrogen-side inlet, eliminating the influence of power fluctuations in the circulating pump 40 and the flow fluctuations of the medium in the pipeline between the circulating pump 40 and the oxygen-side or hydrogen-side inlet, resulting in more accurate measurement results. Based on the same principle, the second regulating valve 12 is preferably located between the second differential pressure measuring component dp2 and the oxygen-side gas-liquid separator 20; the fourth regulating valve 121 is located between the second differential pressure measuring component dp2 and the hydrogen-side gas-liquid separator 30. That is, the second differential pressure measuring component dp2 is directly connected to the oxygen-side outlet and the hydrogen-side outlet, without any other potentially influencing components in between.

[0053] Furthermore, as shown in the figure, the electrolytic cell differential pressure control device in the alkaline electrolysis hydrogen production system also includes pressure regulating valves, an oxygen-side gas-liquid separator outlet connected to the oxygen-side outlet of the electrolytic cell, and a hydrogen-side gas-liquid separator outlet connected to the hydrogen-side outlet of the electrolytic cell, as shown in the figure as a first pressure regulating valve 13 and a second pressure regulating valve 14. The pressure regulating valves adjust the liquid levels of the two gas-liquid separators to meet the requirements, thereby ensuring that the pressure difference between the oxygen-side outlet and the hydrogen-side outlet meets the requirements.

[0054] In some solutions, such as Figure 4 As shown, the technical solution of this application provides a method for controlling the differential pressure of an electrolyzer in an alkaline electrolysis hydrogen production system, including:

[0055] S10: Obtain the inlet pressure difference between the oxygen side and the hydrogen side of the electrolyzer.

[0056] Combination Figure 1 and Figure 2 As shown, the present application adds a first differential pressure measuring component dp1 at the inlet of the electrolyzer 10 based on the current technology. Therefore, the inlet pressure difference between the oxygen side and the hydrogen side of the electrolyzer can be directly obtained.

[0057] S20: If the inlet pressure difference is not within the first set range, adjust the inlet pressure value of the oxygen side or the hydrogen side until the inlet pressure difference is maintained within the first set range.

[0058] In this application, a first regulating valve 11 is added to the oxygen-side inlet of the electrolyzer, a third regulating valve 111 is added to the hydrogen-side inlet, a second regulating valve 12 is added to the oxygen-side outlet of the electrolyzer, and a fourth regulating valve 121 is added to the hydrogen-side outlet. The inlet pressure difference between the oxygen-side and hydrogen-side inlets of the electrolyzer is controlled by adjusting the opening degrees of the first regulating valve 11, the second regulating valve 12, the third regulating valve 111, and the fourth regulating valve 121. The process of adjusting these valves is a coordinated adjustment process.

[0059] S30: Obtain the outlet pressure difference between the oxygen and hydrogen sides of the electrolyzer.

[0060] In this application, a second differential pressure measuring component dp2 is installed at the outlet of the electrolyzer 10, so the outlet pressure difference between the oxygen side and the hydrogen side of the electrolyzer can be directly obtained.

[0061] S40: If the outlet pressure difference is not within the second set range, adjust the outlet pressure value of the oxygen side or the hydrogen side until the outlet pressure difference is maintained within the second set range.

[0062] The pressure difference between the oxygen side outlet and the hydrogen side outlet of the electrolyzer is controlled by adjusting the opening of the first regulating valve 11, the second regulating valve 12, the third regulating valve 111 and the fourth regulating valve 121.

[0063] According to the above-described scheme of this application, when the first differential pressure measuring component dp1 between the oxygen side inlet and the hydrogen side inlet of the electrolyzer shows that the hydrogen side pressure is high, the first regulating valve 11 at the oxygen side inlet is increased or the second regulating valve 12 at the oxygen side outlet is decreased to increase the oxygen side pressure and reduce the pressure difference between the hydrogen side and the oxygen side inlet; or, the third regulating valve 111 at the hydrogen side inlet is decreased or the fourth regulating valve 121 at the hydrogen side outlet is increased to decrease the hydrogen side pressure and reduce the pressure difference between the hydrogen side and the oxygen side inlet.

[0064] When the first differential pressure measuring component dp1 between the oxygen-side inlet and the hydrogen-side inlet of the electrolyzer indicates that the hydrogen-side pressure is low, the second regulating valve 12 at the oxygen-side outlet is increased, or the first regulating valve 11 at the oxygen-side inlet is decreased, to reduce the oxygen-side pressure and decrease the pressure difference between the hydrogen-side and oxygen-side inlets. Alternatively, the third regulating valve 111 at the hydrogen-side inlet is increased, or the fourth regulating valve 121 at the hydrogen-side outlet is decreased, to increase the hydrogen-side pressure and decrease the pressure difference between the hydrogen-side and oxygen-side inlets.

[0065] Combination Figure 2As shown, when the opening of the first regulating valve 11 is increased, the oxygen-side pressure value of the electrolytic cell changes in the direction of increasing; when the opening of the first regulating valve is decreased, the oxygen-side pressure value of the electrolytic cell changes in the direction of decreasing; when the opening of the second regulating valve 12 is increased, the oxygen-side pressure value of the electrolytic cell changes in the direction of decreasing; when the opening of the second regulating valve 12 is decreased, the oxygen-side pressure value of the electrolytic cell changes in the direction of increasing.

[0066] When the opening of the third regulating valve 111 is increased, the hydrogen-side pressure value of the electrolyzer changes in the direction of increasing; when the opening of the third regulating valve 111 is decreased, the hydrogen-side pressure value of the electrolyzer changes in the direction of decreasing; when the opening of the fourth regulating valve 121 is increased, the hydrogen-side pressure value of the electrolyzer changes in the direction of decreasing; when the opening of the fourth regulating valve 121 is decreased, the hydrogen-side pressure value of the electrolyzer changes in the direction of increasing. Therefore, in specific implementations, depending on the actual application scenario, there are multiple adjustment methods to adjust each valve when changing the inlet pressure difference or outlet pressure difference between the hydrogen and oxygen sides. Preferably, if the inlet pressure difference does not meet the requirements, the first regulating valve 11 and the third regulating valve 111 are adjusted first; if the outlet pressure difference does not meet the requirements, the second regulating valve 12 and the fourth regulating valve 121 are adjusted first. The above adjustment process may require multiple adjustments until both the inlet pressure difference and the outlet pressure difference meet the requirements.

[0067] Preferably, in some solutions of the alkaline electrolytic hydrogen production system, the electrolyzer pressure difference control method measures the liquid level of the oxygen-side gas-liquid separator connected to the oxygen-side outlet of the electrolyzer and the liquid level of the hydrogen-side gas-liquid separator connected to the hydrogen-side outlet of the electrolyzer using a differential pressure transmitter; obtains the liquid level difference between the oxygen-side and hydrogen-side gas-liquid separators; and controls the liquid level difference to a set value, thus maintaining the outlet pressure difference within a second set range. In the above solutions, the first set range is preferably 0-100 Pa, more preferably 0-50 Pa, and the inlet pressure value of the oxygen side is greater than or equal to the inlet pressure value of the hydrogen side; the second set range is 0-200 Pa, more preferably 0-100 Pa, and the outlet pressure value of the oxygen side is greater than or equal to the outlet pressure value of the hydrogen side. The above-mentioned solution of this application accurately measures the pressure difference between the hydrogen and oxygen sides at the inlet and outlet of the electrolyzer under different loads by installing differential pressure measuring components at the inlet and outlet of the electrolyzer. By installing regulating valves at the inlet and outlet of the electrolyzer, the pressure on the hydrogen and oxygen sides at the inlet and outlet of the electrolyzer is balanced, thereby reducing the safety risk of hydrogen in oxygen, expanding the system operating load, reducing the oxygen concentration in hydrogen, improving hydrogen quality, significantly enhancing the compatibility with fluctuating new energy sources, and improving the system's safety, stability, and economy.

[0068] As needed, the above technical solutions can be combined to achieve the best technical effect.

[0069] The above are merely the principles and preferred embodiments of this application. It should be noted that, for those skilled in the art, several other modifications can be made based on the principles of this application, and these modifications should also be considered within the scope of protection of this application.

Claims

1. A differential pressure control device for an electrolyzer in an alkaline electrolysis hydrogen production system, characterized in that, include: The first differential pressure measuring component is used to detect the inlet pressure difference between the oxygen side and the hydrogen side of the electrolyzer; The second differential pressure measuring component is used to detect the outlet pressure difference between the oxygen side and the hydrogen side of the electrolyzer; The first regulating valve is located at the hydrogen-side inlet or the oxygen-side inlet of the electrolytic cell; The second regulating valve is located at the hydrogen-side outlet or the oxygen-side outlet of the electrolyzer. The controller receives the inlet pressure difference sent by the first differential pressure measuring component and the outlet pressure difference sent by the second differential pressure measuring component, and adjusts the first regulating valve and / or the second regulating valve according to the inlet pressure difference and the outlet pressure difference, so that: The inlet pressure value of the oxygen side is greater than or equal to the inlet pressure value of the hydrogen side, and the inlet pressure difference between the oxygen side and the hydrogen side is maintained within a first set range. The outlet pressure value of the oxygen side is greater than or equal to the outlet pressure value of the hydrogen side, and the outlet pressure difference between the oxygen side and the hydrogen side is maintained within a second set range.

2. The differential pressure control device for the electrolyzer in the alkaline electrolysis hydrogen production system according to claim 1, characterized in that, Also includes: The third regulating valve is respectively located at the hydrogen-side inlet and the oxygen-side inlet of the electrolytic cell, along with the first regulating valve. The fourth regulating valve, along with the second regulating valve, is respectively located at the hydrogen-side outlet and the oxygen-side outlet of the electrolytic cell; The controller adjusts at least one of the first regulating valve, the second regulating valve, the third regulating valve, and the fourth regulating valve according to the inlet pressure difference and the outlet pressure difference, so that: The inlet pressure value of the oxygen side is greater than or equal to the inlet pressure value of the hydrogen side, and the inlet pressure difference between the oxygen side and the hydrogen side is maintained within a first set range. The outlet pressure value of the oxygen side is greater than or equal to the outlet pressure value of the hydrogen side, and the outlet pressure difference between the oxygen side and the hydrogen side is maintained within a second set range.

3. The differential pressure control device for the electrolyzer in the alkaline electrolysis hydrogen production system according to claim 1 or 2, characterized in that: The first differential pressure measuring component is a differential pressure transmitter, and the two ends of the differential pressure transmitter are respectively connected to the oxygen-side inlet and the hydrogen-side inlet of the electrolytic cell; the differential pressure transmitter measures the inlet pressure difference.

4. The electrolytic cell differential pressure control device in the alkaline electrolysis hydrogen production system according to claim 1 or 2, characterized in that: The first differential pressure measuring component includes a pair of pressure sensors and a computing unit; The pair of pressure sensors are respectively installed at the oxygen-side inlet and the hydrogen-side inlet of the electrolytic cell, and are used to detect the oxygen-side inlet pressure value and the hydrogen-side inlet pressure value of the electrolytic cell. The calculation unit receives the oxygen-side inlet pressure value and the hydrogen-side inlet pressure value and calculates the inlet pressure difference.

5. The differential pressure control device for the electrolyzer in the alkaline electrolysis hydrogen production system according to claim 2, characterized in that: Both the first regulating valve and the third regulating valve are located upstream of the first differential pressure measuring component, between the first differential pressure measuring component and the circulating pump.

6. The differential pressure control device for the electrolyzer in the alkaline electrolysis hydrogen production system according to claim 5, characterized in that: The second regulating valve is located between the second differential pressure measuring component and the oxygen-side gas-liquid separator; The fourth regulating valve is located between the second differential pressure measuring component and the hydrogen-side gas-liquid separator.

7. The differential pressure control device for the electrolyzer in the alkaline electrolysis hydrogen production system according to claim 1 or 2, characterized in that, Also includes: A pressure regulating valve is provided at the outlet of the oxygen-side gas-liquid separator connected to the oxygen-side outlet of the electrolyzer, and at the outlet of the hydrogen-side gas-liquid separator connected to the hydrogen-side outlet of the electrolyzer.

8. A method for controlling the differential pressure of an electrolyzer in an alkaline electrolysis hydrogen production system, characterized in that, include: The inlet pressure difference between the oxygen side and the hydrogen side of the electrolyzer is obtained. If the inlet pressure difference is not within a first set range, the inlet pressure value of the oxygen side or the hydrogen side is adjusted until the inlet pressure difference is maintained within the first set range. The outlet pressure difference between the oxygen side and the hydrogen side of the electrolyzer is obtained. If the outlet pressure difference is not within a second set range, the outlet pressure value of the oxygen side or the hydrogen side is adjusted until the outlet pressure difference is maintained within the second set range.

9. The method for controlling the differential pressure of the electrolyzer in the alkaline electrolysis hydrogen production system according to claim 8, characterized in that: The first setting range is 0-100 Pa, and the inlet pressure value of the oxygen side is greater than or equal to the inlet pressure value of the hydrogen side; the second setting range is 0-200 Pa, and the outlet pressure value of the oxygen side is greater than or equal to the outlet pressure value of the hydrogen side.

10. The method for controlling the differential pressure of the electrolyzer in an alkaline electrolysis hydrogen production system according to claim 8 or 9, characterized in that: If a first or third regulating valve is provided on the oxygen inlet side of the electrolyzer, then increasing the opening of the first or third regulating valve will cause the oxygen-side pressure of the electrolyzer to increase; decreasing the opening of the first or third regulating valve will cause the oxygen-side pressure of the electrolyzer to decrease. If a second or fourth regulating valve is provided on the oxygen outlet side of the electrolyzer, then increasing the opening of the second or fourth regulating valve will cause the oxygen-side pressure of the electrolyzer to decrease; decreasing the opening of the second or fourth regulating valve will cause the oxygen-side pressure of the electrolyzer to increase. If a first or third regulating valve is provided on the hydrogen inlet side of the electrolyzer, then increasing the opening of the first or third regulating valve will cause the hydrogen-side pressure of the electrolyzer to increase; decreasing the opening of the first or third regulating valve will cause the hydrogen-side pressure of the electrolyzer to decrease. If a second or fourth regulating valve is provided on the hydrogen outlet side of the electrolyzer, then increasing the opening of the second or fourth regulating valve will cause the hydrogen-side pressure of the electrolyzer to decrease; decreasing the opening of the second or fourth regulating valve will cause the hydrogen-side pressure of the electrolyzer to increase.

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