Fastening method of alkaline hydrogen production electrolytic cell

Abstract

The invention belongs to the technical field of electrolytic bath equipment, and discloses a fastening method of an alkaline hydrogen production electrolytic bath, which comprises the following steps: after assembling a part structure of the electrolytic bath, stretching and pre-tightening the top of a draw-in bolt at intervals by a hydraulic stretcher to prevent each part of the electrolytic bath from moving; and after pre-tightening is completed, the electrolytic bath is subjected to cold tightening and hot tightening for many times, and the electrolytic bath is tightened. And in the pre-tightening, cold tightening and hot tightening processes, a pump station of the hydraulic tensioner is boosted according to a difference value of 3-8 MPa / time, the tension bolt is stretched and fastened, parts of the electrolytic cell are pressed, gaps are eliminated as much as possible, and the sealing gasket is extruded to deform, so that the sealing effect of the electrolytic cell is improved. According to the technical scheme, the fastening effect on the large alkaline hydrogen production electrolytic cell is enhanced, and the long-term use state of the electrolytic cell is more stable.

Description

Technical Field

[0001] The invention belongs to the technical field of electrolytic cell equipment and relates to a fastening method of an alkaline hydrogen production electrolytic cell. Background Art

[0002] With the rapid development of the hydrogen energy industry, alkaline water electrolysis is increasingly being used in various renewable energy hydrogen production scenarios due to its advantages of low energy consumption and low cost. In alkaline water electrolysis hydrogen production systems, the alkaline electrolyzer is the core device, capable of electrolyzing water to produce hydrogen and oxygen.

[0003] Alkaline hydrogen production electrolyzers come in a variety of structural forms, with circular pressurized electrolyzers typically comprising end pressure plates, end plates, plates, cathode mesh, anode mesh, diaphragms, sealing washers, disc springs, tension bolts, nuts, and other components. This type of electrolyzer is composed of a number of stacked electrolysis chambers, each containing a cathode chamber and an anode chamber. A diaphragm prevents the gases generated by the two chambers from communicating with each other. Electrode plates separate the electrolysis chambers, and sealing washers insulate and seal adjacent plates. Once multiple electrolysis chambers are assembled, the end pressure plates on the outside of the end plates are tightened with tension bolts and nuts to secure the entire electrolyzer.

[0004] The tightening effect of a large electrolytic cell affects its sealing performance. Generally, a combination of cold tightening and hot tightening is used to tighten the electrolytic cell. During hot tightening, water vapor is generally introduced into the water inlet of the electrolytic cell for heating. During the heating process, the temperature at the gas outlet is relatively high, while the temperature at the water inlet is relatively low, resulting in uneven heating of the cell body. During cold tightening, local cooling is further insufficient, resulting in insufficient compression force on the electrolytic cell and insufficient deformation of the sealing gasket, thus affecting the sealing effect of the electrolytic cell. If the seal is not good, when hydrogen is produced by electrolysis of water, the hydrogen produced at the cathode and the oxygen produced at the anode will intercommunicate with each other, and the mixture of hydrogen and oxygen will pose a risk of explosion. Summary of the Invention

[0005] The purpose of the present invention is to provide a fastening method for an alkaline hydrogen production electrolyzer, which solves the problem in the prior art that when fastening large circular pressurized alkaline hydrogen production electrolyzers, the sealing effect is poor due to uneven heating of the cell body and insufficient pressing force on the electrolyzer, resulting in an explosion risk in the hydrogen production process.

[0006] The technical solution adopted by the present invention is a method for fastening an alkaline hydrogen production electrolyzer, comprising the following steps: Step 1: After the electrolyzer is assembled, the tension bolts are pre-tightened at intervals using a hydraulic tensioner to compress the distance between the lower and upper pressure plates to the theoretical distance; Step 2: First, perform the first intermittent cold tightening of the tensioning bolts by the hydraulic tensioner, then heat the electrolytic cell to the specified temperature, and then perform the first intermittent hot tightening of the tensioning bolts by the hydraulic tensioner; Step 3: After the temperature of the electrolytic cell drops to room temperature, repeat step 2 to perform the second intermittent cold tightening and the second intermittent hot tightening; Step 4: After the temperature of the electrolytic cell drops to room temperature again, the tension bolts are subjected to a third intermittent cold tightening by means of a hydraulic tensioner; Step 5: After the third cold tightening, the electrolytic cell is tested for air tightness. Tightening is considered completed after passing the air tightness test.

[0007] The present invention is also characterized in that: In step 2, when performing the first intermittent cold tightening, the pressure applied by the hydraulic pump station to the hydraulic tensioner is gradually increased to 35~45MPa; when performing the first intermittent hot tightening, the pressure applied by the hydraulic pump station to the hydraulic tensioner is gradually increased to 35~45MPa again.

[0008] In step 3, when performing the second intermittent cold tightening, the pressure applied by the hydraulic pump station to the hydraulic tensioner is gradually increased to 45~55MPa; when performing the second intermittent hot tightening, the pressure applied by the hydraulic pump station to the hydraulic tensioner is gradually increased to 55~65MPa.

[0009] In step 4, when performing the third intermittent cold tightening, the pressure applied by the hydraulic pump station to the hydraulic tensioner is gradually increased to 55~65MPa.

[0010] The present invention is also characterized in that step 1 includes the following subdivision steps: Step 1.1: Install a hydraulic tensioner at the end of each tensioning bolt where it passes through the upper pressure plate. Connect the hydraulic tensioner to the distributor of the hydraulic pump station via a hydraulic pipe. Start the hydraulic pump station to tension the tensioning bolts at intervals and tighten the corresponding nuts. Step 1.2: Replace and install the hydraulic tensioner to the end of the remaining tensioning bolt, then start the hydraulic pump station to stretch the tensioning bolt and tighten the corresponding nut to complete the pre-tightening; Step 1.3: After completing one pre-tightening, the hydraulic pump station increases the pressure once, and repeats steps 1.1 and 1.2 until the distance between the lower end pressure plate and the upper end pressure plate is compressed to the theoretical distance.

[0011] The first intermittent cold tightening and the first intermittent hot tightening in step 2 are the same as the intermittent pre-tightening method. The second cold tightening in step 3 and the third cold tightening in step 4 are the same as the first cold tightening method, and the second hot tightening in step 3 is the same as the first hot tightening method.

[0012] In steps 1 to 4, the hydraulic pump station increases the pressure by a difference of 3~8MPa / time. Each time the pressure is increased, if the pressure does not exceed 3~8MPa and the working stroke of the hydraulic tensioner has been reached, first lock the hydraulic tensioner's dial ring and the corresponding nut, then release the pressure of the hydraulic tensioner. After the pressure relief is completed, continue to pressurize until the pressure rise value reaches 3~8MPa.

[0013] In steps 1 to 4, the tensile force applied to the tightening bolt by the hydraulic tensioner does not exceed the calculated load value of the bolt.

[0014] During the first heat tightening process in step 2 and the second heat tightening process in step 3, an electric steam generator is used to heat the electrolytic cell. The heating method is to heat the entire electrolytic cell to 90±2°C and then keep it warm for 1-2 hours. During the heating process, blind flanges are installed at the water inlet and outlet of the electrolytic cell except for the steam inlet and outlet, and the heating conditions of each area of the cell are checked to ensure uniform heating.

[0015] The present invention is also characterized in that the method of the airtightness test in step 5 is: Inert gas is introduced into the electrolytic cell for air tightness test. The test pressure is 2.0MPa and the pressure is maintained for 30 minutes. After checking that there is no leakage at all connections, it is left to stand for 24 hours. The average hourly pressure relief rate does not exceed 0.5% to be qualified.

[0016] The present invention is also characterized in that the fastening method of the alkaline hydrogen production electrolyzer further includes, if the airtightness test in step 5 fails, then proceeding to step 6, which includes the following sub-steps: Step 6.1: Measure the distance between the lower and upper pressure plates; Step 6.2: Continue to perform interval tensioning and tightening on the tensioning bolts using the hydraulic tensioner. The hydraulic pump station continues to increase the pressure applied to the hydraulic tensioner by 3-8 MPa. Then, perform an air tightness test on the electrolytic cell again. If the air tightness test is qualified, the tightening is considered completed. If the air tightness test still fails, proceed to step 6.3. Step 6.3: Repeat step 6.1. If the measured spacing value changes by ≤3mm compared to the last measured value, disassemble the electrolytic cell and reassemble it, then repeat steps 1-5 to re-tighten it. If the spacing value changes by more than 3mm compared to the last measured value, repeat step 6.2.

[0017] The beneficial effects of the present invention are: The present invention uses a hydraulic tensioner for compression at intervals, ensuring uniform force on each bolt and reducing the risk of uneven load. This eliminates gaps between electrolytic cell components while simultaneously compressing them to prevent them from moving. Furthermore, it maintains the greatest possible balance of pressure across the various components. This intermittent compression also reduces the number of hydraulic tensioner heads required, saving installation costs.

[0018] The present invention simulates the operating conditions of an electrolytic cell under normal operating conditions by combining multiple cold and hot tightening cycles, further reducing the residual gaps between the various components of the electrolytic cell and causing the sealing gasket therein to deform, thereby improving the sealing effect of the electrolytic cell and completing the tightening of the electrolytic cell. During the repeated heating and cooling process, the relative positions of the various components of the electrolytic cell and any local uneliminated gaps can be fine-tuned, making it easier to eliminate residual gaps during the stretching and tightening of the tension bolts. Furthermore, the pressure on each part of the various components of the electrolytic cell is more balanced, and the deformation of the sealing gasket is more uniform, further improving the sealing effect of the electrolytic cell.

[0019] The heating temperature of the electrolytic cell of the present invention is uniform, which can make the sealing gasket fully deform and ensure good sealing effect of the electrolytic cell.

[0020] The present invention enhances the fastening effect of a large alkaline hydrogen production electrolytic cell through the above-mentioned solution, making the long-term use state of the electrolytic cell more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the assembly of the alkaline hydrogen production electrolyzer of the present invention; Figure 2 It is a schematic flow chart of the fastening method of the present invention.

[0022] In the figure: 1. tensioning bolt; 2. butterfly spring; 3. nut; 4. hydraulic tensioner; 5. lower end pressure plate; 6. tank body; 601. lower end plate; 602. upper end plate; 7. upper end pressure plate. DETAILED DESCRIPTION

[0023] The fastening method of the alkaline hydrogen production electrolytic cell proposed in the present invention is implemented on a large circular pressurized electrolytic cell, which is in a vertical state during the assembly and fastening process. Figure 1 shown.

[0024] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Example 1: like Figure 2 As shown, the fastening method of the alkaline hydrogen production electrolyzer includes the following steps: Step 1: After the electrolytic cell is assembled, the tension bolts 1 are pre-tightened at intervals by the hydraulic tensioner 4 to compress the distance between the lower pressure plate 5 and the upper pressure plate 7 to the theoretical distance; Step 2: First, the tension bolt 1 is subjected to a first interval cold tightening by the hydraulic tensioner 4, and then the electrolytic cell is heated to a specified temperature, and then the tension bolt 1 is subjected to a first interval hot tightening by the hydraulic tensioner 4; Step 3: After the temperature of the electrolytic cell drops to room temperature, repeat step 2 to perform the second intermittent cold tightening and the second intermittent hot tightening; Step 4: After the temperature of the electrolytic cell drops to room temperature again, the tension bolt 1 is subjected to a third intermittent cold tightening by the hydraulic tensioner 4; Step 5: After the third cold tightening, the electrolytic cell is tested for air tightness. Tightening is considered completed after passing the air tightness test.

[0026] In step 1 of this embodiment, the theoretical distance between the lower pressing plate 5 and the upper pressing plate 7 is determined according to the dimensions of the electrolytic cell design drawing.

[0027] Since there will be certain gaps between the components of the electrolytic cell during assembly, the purpose of pre-tightening in step 1 is to eliminate the gaps. After the gaps are completely eliminated, pressure is formally applied for cold tightening and hot tightening.

[0028] The fastening method of this embodiment is applicable to the electrolytic cell, in which the number of bolt holes on the lower pressure plate 5 and the upper pressure plate 7 is N, N is an even number greater than or equal to 1, and the N bolt holes are evenly distributed along the circumferential direction of the lower pressure plate 5 or the upper pressure plate 7.

[0029] In this embodiment, the assembly process of the electrolytic cell is as follows: first, the lower end pressure plate 5 is placed at the bottom, and then the cell body 6 composed of multiple electrolysis chambers and plates and other components is assembled from bottom to top above the lower end pressure plate 5, and the lower end plate 601 in the cell body 6 is located above the lower end pressure plate 5; then the tightening bolts 1 are installed, and a tightening bolt 1 is inserted into each bolt hole of the lower end pressure plate 5, and the lower ends of all the tightening bolts 1 are installed with corresponding disc springs 2 and nuts 3; then the upper end pressure plate 7 is hoisted above the upper end plate 602, so that it is aligned with the lower end pressure plate 5 and slowly and steadily placed on the upper end plate 602 of the cell body 6; in a symmetrical and cross-cross manner, the tightening bolts 1 are lifted up one by one using a hoisting tool with threaded holes and inserted into the corresponding bolt holes of the upper end pressure plate 7, and the corresponding disc springs 2 and nuts 3 are installed on the upper ends of the tightening bolts 1 to ensure that each tightening bolt 1 passes vertically through the lower end pressure plate 5 and the upper end pressure plate 7.

[0030] Among them, the lifting tool with a threaded hole is a lifting tool in which the threaded hole is opened on a component that can be raised and lowered. After being connected with the tensioning bolt 1 through the threaded hole, the tensioning bolt 1 can be lifted up and passed through the threaded hole of the upper pressure plate 7 as the component rises, so as to facilitate installation.

[0031] In this embodiment, the disc spring 2 is installed between the lower pressure plate 5 or the upper pressure plate 7 and the nut 3, and the disc spring 2 is installed through a guide. The guide is to facilitate the installation of the disc spring and prevent it from deflecting when subjected to force. Because the disc spring is like a disk, a cylindrical retaining structure is required in the middle of the disk to be placed inside the disc spring.

[0032] The guide piece consists of an integrally formed annular piece and a liner. The annular piece is located at one end of the liner. The outer diameter of the annular piece is larger than the outer wall diameter of the liner. During installation, the annular piece is clamped between the disc spring 2 and the nut 3. The liner is located inside the annular shape of the disc spring 2, guiding the disc spring 2 and making the deformation of the disc spring 2 uniform. At the same time, it also makes the electrolytic cell more evenly stressed during the tightening process, thereby improving the sealing effect of the electrolytic cell.

[0033] In this embodiment, insulating pads are provided in the bolt holes of the lower pressure plate 5 and the upper pressure plate 7, and the tensioning bolt 1 is installed by passing through the insulating pads in the bolt holes. The insulating pads play an insulating role between the upper and lower pressure plates.

[0034] The working principle of this embodiment is as follows: After the component structure of the electrolytic cell is assembled, there will be a certain gap between the components of the electrolytic cell. The hydraulic stretcher 4 is used to stretch and pre-tighten the top of the tensioning bolt 1 in an interval manner to press the components of the electrolytic cell and eliminate the gap as much as possible to prevent the components of the electrolytic cell from moving; at the same time, the pressure on each part of the components of the electrolytic cell is kept as balanced as possible, and the number of pulling heads of the hydraulic stretcher 4 can be reduced.

[0035] After pre-tightening is complete, the electrolytic cell is repeatedly cold-tightened and hot-tightened multiple times to further reduce the remaining gaps between the various components of the electrolytic cell, squeeze the sealing gasket to cause deformation, and improve the sealing effect of the electrolytic cell. During the repeated heating and cooling process, the relative positions of the various components of the electrolytic cell and any local gaps that have not been eliminated can be fine-tuned, making it easier to eliminate residual gaps during the tensioning and tightening process of the tensioning bolts. The pressure on each part of the electrolytic cell components is also more balanced, and the deformation of the sealing gasket is more uniform, further improving the sealing effect of the electrolytic cell.

[0036] The present invention enhances the fastening effect of a large alkaline hydrogen production electrolytic cell through the above-mentioned solution, making the long-term use state of the electrolytic cell more stable.

[0037] Example 2: The fastening method of the alkaline hydrogen production electrolyzer, based on Example 1, further includes: In step 2, when performing the first intermittent cold tightening, the pressure applied by the hydraulic pump station to the hydraulic stretcher 4 is gradually increased to 35~45MPa; when performing the first intermittent hot tightening, the pressure applied by the hydraulic pump station to the hydraulic stretcher 4 is gradually increased to 35~45MPa again.

[0038] In step 3, when performing the second intermittent cold tightening, the pressure applied by the hydraulic pump station to the hydraulic stretcher 4 is gradually increased to 45~55MPa; when performing the second intermittent hot tightening, the pressure applied by the hydraulic pump station to the hydraulic stretcher 4 is gradually increased to 55~65MPa.

[0039] In step 4, when performing the third intermittent cold tightening, the pressure applied by the hydraulic pump station to the hydraulic stretcher 4 is gradually increased to 55-65 MPa.

[0040] The working principle of this embodiment is the same as that of embodiment 1 and will not be described in detail.

[0041] Example 3: The method for fastening an alkaline hydrogen production electrolyzer is based on Example 1, wherein step 1 includes the following subdivision steps: Step 1.1: Install a hydraulic tensioner 4 at the end of each tension bolt 1 that passes through the upper pressure plate 7, as shown in the following example: Figure 2 As shown, the hydraulic tensioner 4 is connected to the distributor of the hydraulic pump station through a hydraulic pipe; the hydraulic pump station is started to perform interval stretching on the tensioning bolts 1 and tighten the corresponding nuts 3; Step 1.2: Replace and install the hydraulic tensioner 4 to the end of the remaining tensioning bolt 1, then start the hydraulic pump station to stretch the tensioning bolt 1 and tighten the corresponding nut 3 to complete the pre-tightening; Step 1.3: After completing the preload, increase the pressure in the hydraulic pump station. Repeat steps 1.1 and 1.2 until the gap between the lower and upper pressure plates 5 and 7 is compressed to the theoretical distance. This completes the preload. After preloading to the theoretical distance, the longitudinal gaps between the components of the electrolytic cell approach zero.

[0042] In step 2 of this embodiment, the first intermittent cold tightening and the first intermittent hot tightening are both the same as the intermittent pre-tightening.

[0043] The second cold tightening method in step 3 and the third cold tightening method in step 4 are the same as the first cold tightening method, and the second hot tightening method in step 3 is the same as the first hot tightening method.

[0044] In steps 1 to 4 of this embodiment, the hydraulic pump station increases the pressure by a difference of 3 to 8 MPa per time. Each time the pressure is increased, if the pressure does not exceed 3 to 8 MPa and the working stroke of the hydraulic tensioner 4 has been reached, the pull ring of the hydraulic tensioner 4 is first locked with the corresponding nut 3, and then the hydraulic tensioner 4 is depressurized. After the pressure is released, the pressure is continued until the pressure rise value reaches 3 to 8 MPa.

[0045] In this embodiment, each time the hydraulic pump station increases pressure, it is necessary to stretch and tighten all the tension bolts 1 before increasing pressure again.

[0046] In steps 1 to 4 of this embodiment, the tensile force applied to the tensioning bolt 1 by the hydraulic tensioner 4 does not exceed the calculated load value of the bolt.

[0047] In this embodiment, the model of the hydraulic pump station used is EP-150.

[0048] The working principle of this embodiment is the same as that of embodiment 1 and will not be described in detail.

[0049] Example 4: The tightening method for an alkaline hydrogen production electrolyzer is based on Example 1, wherein an electric steam generator is used to heat the electrolyzer during both the first heat tightening in step 2 and the second heat tightening in step 3. The heating method is to heat the entire electrolyzer to 90±2°C and then maintain the temperature for 1-2 hours. During the heating process, blind flanges are installed at the water inlet and outlet of the electrolyzer, excluding the steam inlet and outlet. The heating status of each area of the cell body 6 is checked to ensure uniform heating.

[0050] In this embodiment, the model of the electric steam generator used is LDR0.08-0.7.

[0051] The working principle of this embodiment is the same as that of embodiment 1 and will not be described in detail.

[0052] Example 5: The fastening method of the alkaline hydrogen production electrolyzer is based on Example 1, wherein the method for the airtightness test in step 5 is: Inert gas is introduced into the electrolytic cell for air tightness test. The test pressure is 2.0MPa and the pressure is maintained for 30 minutes. After checking that there is no leakage at all connections, it is left to stand for 24 hours. The average hourly pressure relief rate does not exceed 0.5% to be qualified.

[0053] The working principle of this embodiment is the same as that of embodiment 1 and will not be described in detail.

[0054] Example 6: The fastening method of the alkaline hydrogen production electrolyzer, based on Example 5, further includes: If the airtightness test in step 5 fails, proceed to step 6, which includes the following sub-steps: Step 6.1: Measure the distance between the lower pressing plate 5 and the upper pressing plate 7; Step 6.2: Continue to perform interval tensioning and tightening on the tensioning bolt 1 using the hydraulic tensioner 4. The hydraulic pump station continues to increase the pressure applied to the hydraulic tensioner 4 by 3-8 MPa. Then, perform an air tightness test on the electrolytic cell again. If the air tightness test is qualified, the tightening is considered completed. If the air tightness test still fails, proceed to step 6.3. Step 6.3: Repeat step 6.1. If the measured spacing value changes by ≤3mm compared to the last measured value, disassemble the electrolytic cell and repeat steps 1-5 to reassemble and tighten. If the spacing value changes by more than 3mm compared to the last measured value, repeat step 6.2.

[0055] In step 6.3 of this embodiment, if the measured spacing value changes by ≤3mm compared to the value measured last time, it means that the deformation of the sealing gasket has almost reached its limit. Further pressurization will not effectively increase the sealing effect and may even damage the sealing gasket and other components, so it has to be disassembled and reinstalled.

[0056] The working principle of this embodiment is the same as that of embodiment 1 and will not be described in detail.

Claims

1. A method for fastening an alkaline hydrogen production electrolyzer, characterized in that: The following steps are involved: Step 1: After the electrolytic cell is assembled, the tension bolts (1) are pre-tightened at intervals by a hydraulic tensioner (4) to compress the distance between the lower end pressure plate (5) and the upper end pressure plate (7) to a theoretical distance; Step 2: First, the tension bolt (1) is subjected to a first interval cold tightening by the hydraulic tensioner (4), and then the electrolytic cell is heated to a specified temperature, and then the tension bolt (1) is subjected to a first interval hot tightening by the hydraulic tensioner (4); Step 3: After the temperature of the electrolytic cell drops to room temperature, repeat step 2 to perform the second intermittent cold tightening and the second intermittent hot tightening; Step 4: After the temperature of the electrolytic cell is lowered to room temperature again, the tension bolt (1) is subjected to a third intermittent cold tightening by the hydraulic tensioner (4); Step 5: After the third cold tightening, the electrolytic cell is tested for air tightness. Tightening is considered completed after passing the air tightness test.

2. The method for fastening an alkaline hydrogen production electrolyzer according to claim 1, characterized in that: In step 2, when performing the first interval cold tightening, the pressure applied by the hydraulic pump station to the hydraulic stretcher (4) is gradually increased to 35-45 MPa; when performing the first interval hot tightening, the pressure applied by the hydraulic pump station to the hydraulic stretcher (4) is again gradually increased to 35-45 MPa; In step 3, when performing the second interval cold tightening, the pressure applied by the hydraulic pump station to the hydraulic stretcher (4) is gradually increased to 45-55 MPa; when performing the second interval hot tightening, the pressure applied by the hydraulic pump station to the hydraulic stretcher (4) is gradually increased to 55-65 MPa; In step 4, when performing the third interval cold tightening, the pressure applied by the hydraulic pump station to the hydraulic stretcher (4) is gradually increased to 55~65MPa.

3. The fastening method of the alkaline hydrogen production electrolyzer according to claim 1, characterized in that: Step 1 includes the following sub-steps: Step 1.1: Install a hydraulic tensioner (4) at the end of each tensioning bolt (1) passing through the upper end pressure plate (7), and connect the hydraulic tensioner (4) to the distributor of the hydraulic pump station through a hydraulic pipe; start the hydraulic pump station, stretch the tensioning bolts (1) at intervals, and tighten the corresponding nuts (3); Step 1.2: Replace and install the hydraulic tensioner (4) to the end of the remaining tensioning bolt (1), then start the hydraulic pump station to stretch the tensioning bolt (1) and tighten the corresponding nut (3) to complete the pre-tightening; Step 1.3: After completing one pre-tightening, the hydraulic pump station increases the pressure once, and repeats steps 1.1 and 1.2 until the distance between the lower end pressure plate (5) and the upper end pressure plate (7) is compressed to the theoretical distance.

4. The method for fastening an alkaline hydrogen production electrolyzer according to claim 3, characterized in that: The first interval cold tightening and the first interval hot tightening in step 2 are the same as the interval pre-tightening method; The second cold tightening method in step 3 and the third cold tightening method in step 4 are the same as the first cold tightening method, and the second hot tightening method in step 3 is the same as the first hot tightening method.

5. The fastening method of the alkaline hydrogen production electrolyzer according to claim 4, characterized in that: In steps 1 to 4, the hydraulic pump station increases the pressure by a difference of 3 to 8 MPa per time; Each time the pressure is increased, if the pressure does not exceed 3~8MPa and has reached the working stroke of the hydraulic tensioner (4), the dial ring of the hydraulic tensioner (4) and the corresponding nut (3) are first locked, and then the hydraulic tensioner (4) is depressurized. After the depressurization is completed, the pressure is continued until the pressure rise value reaches 3~8MPa.

6. The method for fastening an alkaline hydrogen production electrolyzer according to claim 4, characterized in that: In steps 1 to 4, the tensile force applied to the tensioning bolt (1) by the hydraulic tensioner (4) does not exceed the calculated load value of the bolt.

7. The method for fastening an alkaline hydrogen production electrolyzer according to claim 4, characterized in that: During the first heat tightening process in step 2 and the second heat tightening process in step 3, an electric steam generator is used to heat the electrolytic cell. The heating method is to heat the entire electrolytic cell to 90±2°C and then keep it warm for 1~2 hours. During the heating process, blind flanges are installed at the water inlet and outlet of the electrolytic cell except for the steam inlet and outlet, and the heating conditions of each area of the cell body (6) are checked to ensure that it is heated evenly.

8. The method for fastening an alkaline hydrogen production electrolyzer according to claim 1, characterized in that: The method for the air tightness test in step 5 is: Inert gas is introduced into the electrolytic cell for air tightness test. The test pressure is 2.0MPa and the pressure is maintained for 30 minutes. After checking that there is no leakage at all connections, it is left to stand for 24 hours. The average hourly pressure relief rate does not exceed 0.5% to be qualified.

9. The method for fastening an alkaline hydrogen production electrolyzer according to claim 8, characterized in that: The method further includes: if the airtightness test in step 5 fails, proceeding to step 6, which includes the following sub-steps: Step 6.1: Measure the distance between the lower pressure plate (5) and the upper pressure plate (7); Step 6.2: Continue to perform interval tensioning and tightening on the tensioning bolt (1) through the hydraulic tensioner (4), and continue to increase the pressure applied by the hydraulic pump station to the hydraulic tensioner (4) by 3~8MPa, and then perform an air tightness test on the electrolytic cell again. After the air tightness test is qualified, it is considered that the tightening is completed. If the air tightness test is still unqualified, proceed to step 6.3; Step 6.3: Repeat step 6.

1. If the measured spacing value changes by ≤3mm compared to the last measured value, disassemble the electrolytic cell and reassemble it, then repeat steps 1-5 to re-tighten it. If the spacing value changes by more than 3mm compared to the last measured value, repeat step 6.2.

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