A fastening method for an alkaline water electrolysis hydrogen production electrolyzer

Abstract

The invention discloses a fastening method for an alkaline water electrolysis hydrogen production electrolyzer, belonging to the technical field of alkaline water electrolysis hydrogen production systems. Specifically, the internal structure of the electrolyzer is assembled, and an upper pressure plate is covered on its top. Immediately, several tie rods are passed through the connection holes of the two pressure plates, and a tension bolt stretcher is connected to the end of the tie rod passing through the pressure plate. The tension bolt stretcher is pre-tightened to clamp the electrolyzer to prevent the displacement of each component of the electrolyzer. Then, the remaining electrolyzer tie rods are passed through, and the tension bolt stretcher is symmetrically pre-tightened. The hydraulic pump station is pressurized at intervals of 5-10 MPa. After the pressure plate is pressed tightly by pressurization, the position of the pressure plate is locked, the tension bolt stretcher is depressurized, and after the pressure plate is unlocked, the tension bolt stretcher is pressurized again, and this is carried out in sequence until the cold tightening is completed; after the electrolyzer is vacuum-treated and externally heated with a gradient temperature rise, the pressure plate is thermally tightened to complete the fastening of the electrolyzer pressure plate. The invention enhances the fastening effect and sealing performance of the electrolyzer.

Description

Technical Field

[0001] The present invention relates to a fastening method for an alkaline water electrolysis hydrogen production electrolyzer, belonging to the technical field of alkaline water electrolysis hydrogen production systems. Background Art

[0002] The alkaline water electrolysis hydrogen production electrolyzer is the core equipment of the alkaline water electrolysis hydrogen production system. The performance of the electrolyzer has a direct relationship with the hydrogen production efficiency of the entire hydrogen production system; the manufacturing cost of the electrolyzer accounts for a large proportion of the total equipment manufacturing cost, and the higher the hydrogen production amount per unit time of the equipment, the higher the proportion of the electrolyzer in the total equipment manufacturing cost.

[0003] The internal structural forms of electrolyzers vary, but generally include bipolar plates, electrode frames, anode electrodes, cathode electrodes, diaphragms, gaskets, etc. Some electrolyzers are also specially provided with current collectors, and externally there are end pressing plates, bolt and nut fasteners, etc., as Figure 2 shown.

[0004] After the installation of each component of the electrolyzer is completed, a certain number of tension bolt stretchers are required to tighten it. The tightening process is generally cold tightening followed by hot tightening. During the tightening process, deformation and misalignment of components need to be avoided to ensure the sealing performance of the electrolyzer.

[0005] The existing method is to perform hot tightening under normal pressure of the electrolyzer. A large amount of air accumulates inside, and steam cannot be effectively conducted during the hot tightening process, resulting in uneven heating during the heating process of the electrolyzer; at the same time, it is not conducive to accurately controlling the heating temperature value and temperature gradient, resulting in an error between the set temperature value and the actual value, and uneven heating rate, resulting in deformation and misalignment of the internal components of the electrolyzer due to uneven temperature, thus affecting the sealing effect of the electrolyzer. Summary of the Invention

[0006] In order to solve the above existing problems, the present invention discloses a fastening method for an alkaline water electrolysis hydrogen production electrolyzer, and its specific technical solution is as follows:

[0007] A fastening method for an alkaline water electrolysis hydrogen production electrolyzer includes the following steps:

[0008] Step 1: The outside of the electrolyzer is an insulating sleeve, the two ends of the electrolyzer are encapsulated with end covers, the internal structure of the electrolyzer is assembled, and an end pressing plate is covered on its top. Immediately, 4 tie rods distributed in a cross shape pass through the connection holes of the two end pressing plates, and a tension bolt stretcher is connected to the end of the tie rod passing through the end pressing plate to seal the electrolyzer. The tension bolt stretchers are all connected to a distributor through hydraulic pipes, the distributor is connected with a hydraulic pump, and the hydraulic pump is connected with a hydraulic pumping station;

[0009] Step 2: Preloading: Tighten the bolt tensioner by cold tightening until the hydraulic pump pressure is above the minimum bolt load to clamp the electrolytic cell to prevent the components of the electrolytic cell from moving, and then insert the remaining electrolytic cell tie rods;

[0010] Step 3: Cold Tightening and Fastening: Cold tighten all bolt tensioners until the hydraulic pump pressure is above the minimum bolt load. During cold tightening, the bolt tensioners are preloaded symmetrically, and the fastening sequence is in a cross form, that is, diagonally paired distribution. The hydraulic pump station raises the pressure at intervals of 5 - 10 MPa until the pressure is raised above the calculated minimum bolt load;

[0011] Step 4: Lock the collar in the bolt tensioner with the nut, relieve the pressure of the bolt tensioner. After the bolt tensioner is completely depressurized, fix the bolt tensioner to the tie rod, unlock the collar and nut in the bolt tensioner, and then raise the pressure of the bolt tensioner until the pressure of the bolt tensioner is raised above the calculated minimum bolt load;

[0012] Step 5: Repeat Step 4 until the tie rod is pulled to the predetermined position or the bolt tensioner reaches the predetermined pressure;

[0013] Step 6: Lock the collar in the bolt tensioner with the nut, relieve the pressure of the bolt tensioner, and connect the bolt tensioner to the tie rod beside it;

[0014] Step 7: Repeat Steps 3 - 5 to complete the cold tightening and fastening of all tie rods;

[0015] Step 8: Thermal Tightening and Fastening: Evacuate the electrolytic cell to 0.1 - 10 kPa. Under vacuum conditions, gradually thermally tighten by gradually increasing the steam temperature in a stepped manner. At each thermal tightening temperature gradient, perform a thermal tightening and fastening. The thermal tightening and fastening method is the same as cold tightening. Raise the temperature gradient by one more step and repeat the thermal tightening and fastening again until the temperature rises to the specified temperature and perform the last thermal tightening and fastening;

[0016] Step 9: After the thermal tightening is completed and the electrolytic cell is cooled, tighten the bolt tensioner again;

[0017] Step 10: Complete the fastening of the end plate of the electrolytic cell.

[0018] Further, a number of connection holes are provided on the end plate. Among all the connection holes, tie rods are inserted into every other connection hole, and there is a tie rod at the symmetric point of each tie rod along the center of the end plate.

[0019] Further, the heating rate during thermal tightening is 0 - 10 °C / min, keep warm and constant temperature for 1 - 10 h, detect the temperature uniformity of each area, and the allowable tolerance is ±2 °C.

[0020] Further, the hydraulic pump pressure value in Step 2 is 30 - 50 MPa.

[0021] Further, the pressure value of the hydraulic pump in step 3 is 50 - 70 Mpa; the pressure value of the hydraulic pump during the thermal tightening in step 8 is 50 - 70 Mpa.

[0022] Further, in step 8, it is finally thermally tightened to 100 - 150 °C.

[0023] Further, the pressure value of the hydraulic pump for re - tightening the tension bolt stretcher in step 9 is 30 - 50 Mpa.

[0024] Further, nuts and disc springs are respectively sleeved at both ends of the pull rod, and the disc spring is located between the nut and the end pressing plate.

[0025] Further, it also includes step 11: airtightness test: inert gas is pressurized into the electrolytic cell, and within 60 minutes of pressure holding, it is detected that there is no air leakage at all seals and joints. After pressure holding for 24 hours, the average hourly leakage rate does not exceed 0.5%.

[0026] Further, after the electrolytic cell is turned over and placed horizontally, an airtightness test is carried out again, and the test process is as in step 11.

[0027] The nut in the stretcher of the present invention is usually a hexagonal nut.

[0028] The beneficial effects of the present invention are:

[0029] The present invention eliminates the risk that the steam cannot heat due to local air entrapment during the thermal tightening of the electrolytic cell.

[0030] The present invention can accurately control the stepped heating temperature of the steam, enhancing the tightening effect and airtightness of the electrolytic cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is the flow chart of the present invention,

[0032] Figure 2 is the explosion schematic diagram of the electrolytic cell of the present invention,

[0033] Figure 3 is the side view schematic diagram of the electrolytic cell of the present invention,

[0034] List of reference numerals: 1 - end pressing plate, 2 - electrolytic cell, 3 - pull rod, 4 - disc spring, 5 - nut, 6 - hydraulic pump. EMBODIMENTS

[0035] The following further clarifies the present invention in conjunction with the drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and not to limit the scope of the present invention.

[0036] Combined with the attached Figure 2-3As can be seen, several component names related to this patent are simply noted in the figure, which are in sequence: end pressing plate 1, electrolytic cell 2, tie rod 3, disc spring 4, nut 5, and hydraulic pump 6. The structure of the electrolytic cell of this patent and the construction parts of the method of this patent are visually introduced through the attached drawings. Combining Figure 2 , the method of this patent is constructed on the outer side of the pressing plate cover and is used to tightly press the end cover plate of the electrolytic cell to ensure the stability of the internal space of the electrolytic cell. Combining Figure 1 As can be seen, a disc spring 4 is sleeved on the tie rod outside the end pressing plate 1, and the nut 5 is threadedly connected to the tie rod 3. The disc spring 4 is located between the nut 5 and the end pressing plate 1.

[0037] The specific implementation method of the present invention is as follows:

[0038] A fastening method for an alkaline water electrolysis hydrogen production electrolytic cell includes the following steps:

[0039] Step 1: The outside of the electrolytic cell is an insulating sleeve. The two ends of the electrolytic cell are encapsulated with end cover plates. The internal structure of the electrolytic cell is assembled. An end pressing plate is covered on its top. Immediately, 4 tie rods distributed in a cross shape pass through the connection holes of the two end pressing plates, and a tension bolt stretcher is connected to the end of the tie rod passing through the end pressing plate to seal the electrolytic cell. The tension bolt stretchers are all connected to a distributor through hydraulic pipes. The distributor is connected with a hydraulic pump, and the hydraulic pump is connected to a hydraulic pump station; nuts and disc springs are respectively sleeved at both ends of the tie rod, and the disc spring is located between the nut and the end pressing plate.

[0040] Step 2: Pre-tightening: The tension bolt stretcher is cold-tightened until the pressure value of the hydraulic pump is 30 - 50 MPa to clamp the electrolytic cell to prevent the positions of the components of the electrolytic cell from shifting, and then the remaining electrolytic cell tie rods are inserted.

[0041] Step 3: Cold-tightening and fastening: All tension bolt stretchers are cold-tightened until the pressure of the hydraulic pump is above the minimum bolt load. During cold-tightening, the tension bolt stretchers are symmetrically pre-tightened, and the fastening sequence is in a cross form, that is, diagonally paired distribution. The hydraulic pump station is pressurized at intervals of 5 - 10 MPa until the pressure value of the hydraulic pump rises to 50 - 70 Mpa.

[0042] Step 4: Lock the dial in the tension bolt stretcher with the nut, relieve the pressure of the tension bolt stretcher. After the tension bolt stretcher is completely depressurized, then fix the tension bolt stretcher to the tie rod, unlock the dial in the tension bolt stretcher from the nut, and then pressurize the tension bolt stretcher until the tension bolt stretcher is pressurized above the calculated minimum bolt load.

[0043] Step 5: Repeat Step 4 until the tie rod is pulled to the predetermined position or the tension bolt stretcher reaches the predetermined pressure.

[0044] Step 6: Lock the dial ring inside the tension bolt stretcher with the nut, relieve the pressure of the tension bolt stretcher, and connect the tension bolt stretcher to the tie rod beside it;

[0045] Step 7: Repeat Steps 3 - 5 to complete the cold tightening of all tie rods;

[0046] Step 8: Thermal tightening: Evacuate the electrolytic cell to 0.1 - 10 kPa. Under vacuum conditions, gradually perform thermal tightening by gradually increasing the steam temperature in a stepped manner. The heating rate for thermal tightening is 0 - 10 °C / min, keep warm and constant temperature for 1 - 10 h, and detect the temperature uniformity in each zone with a tolerance of ±2 °C. At each thermal tightening temperature gradient, perform thermal tightening once. The method of thermal tightening is the same as that of cold tightening. Then increase the temperature gradient by one more step and repeat the thermal tightening again until the temperature rises to the specified temperature and perform the last thermal tightening to reach the set end plate spacing; during the thermal tightening process, the pressure value of the hydraulic pump is 50 - 70 Mpa.

[0047] Step 9: After the thermal tightening is completed and the electrolytic cell cools down, tighten the tension bolt stretcher again to 30 - 50 MPa;

[0048] Step 10: Complete the tightening of the end plates of the electrolytic cell.

[0049] Step 11: Air tightness test: Pressurize the electrolytic cell with an inert gas. During the 60 - minute pressure holding period, detect that there is no air leakage at all seals and connections. Keep the pressure for 24 h, and the average hourly leakage rate does not exceed 0.5%.

[0050] After the electrolytic cell is flipped and placed horizontally, perform an air tightness test again. The test process is as described in Step 11. Example

[0051] See Figure 1 , the process of the method of the present invention is as follows:

[0052] (1) Place the electrolytic cell vertically. After the internal assembly of the electrolytic cell is completed and the end plate is covered on the top of the electrolytic cell, immediately insert 4 tension bolts symmetrically and cold tighten them to a hydraulic pump pressure of 35 MPa (above the minimum bolt load) to clamp the electrolytic cell to prevent the displacement of each component of the electrolytic cell, and then insert the remaining tie rods of the electrolytic cell.

[0053] (2) Cold tighten all tie rods to a hydraulic pump pressure of 65 MPa (above the minimum bolt load). When cold tightening, the tension bolts are symmetrically pre-tightened, and the tightening sequence is in a cross form. The hydraulic pump station raises the pressure at intervals of 5 MPa until the pressure rises above the calculated minimum bolt load;

[0054] (3) Evacuate the electrolytic cell to 0.1 Pa. Under vacuum conditions, gradually perform thermal tightening by gradually increasing the temperature of the steam in a stepped manner. The method of thermal tightening is the same as that of cold tightening. When the set distance between the end pressing plates is reached, heat to 115 °C, and the pressure of the hydraulic pump of the tensioner is 68 MPa (above the minimum bolt load);

[0055] (4) The heating rate during thermal tightening is 5 °C / min. Keep warm and constant temperature for 1 h, and detect the temperature uniformity in each area. The allowable tolerance is ±2 °C;

[0056] (5) After the thermal tightening is completed and the electrolytic cell is cooled, tighten the tensioning bolts again for 40 MPa cold tightening (above the minimum bolt load) to control the compression amount of the disc spring;

[0057] (6) After the electrolytic cell is tightened, conduct a nitrogen medium airtightness test. There is no air leakage at all seals and joints within 30 min; keep the pressure for 24 h, and the average hourly leakage rate does not exceed 0.5%;

[0058] After the electrolytic cell is turned over and placed horizontally, conduct an airtightness test again. The method and qualified standard are the same as the above requirements. Example

[0059] (1) Place the electrolytic cell vertically. After the internal assembly of the electrolytic cell is completed, immediately cover the upper end pressing plate on the top of the electrolytic cell, then symmetrically insert 4 tensioning bolts and cold tighten them to the pressure of the hydraulic pump of 40 MPa (above the minimum bolt load) to clamp the electrolytic cell to prevent the positions of all components of the electrolytic cell from shifting, and then insert the remaining electrolytic cell tie rods.

[0060] (2) Cold tighten all tie rods to the pressure of the hydraulic pump of 60 MPa (above the minimum bolt load). During cold tightening, symmetrically pre-tighten the tensioning bolts, and the tightening sequence is in the form of a cross. The hydraulic pump station increases the pressure at intervals of 10 MPa until the pressure rises above the calculated minimum bolt load;

[0061] (3) Evacuate the electrolytic cell to 10 Pa. Under vacuum conditions, gradually perform thermal tightening by gradually increasing the temperature of the steam in a stepped manner. The method of thermal tightening is the same as that of cold tightening. When the set distance between the end pressing plates is reached, heat to 135 °C, and the pressure of the hydraulic pump of the tensioner is 70 MPa (above the minimum bolt load);

[0062] (4) The heating rate during thermal tightening is 1 °C / min. Keep warm and constant temperature for 1 h, and detect the temperature uniformity in each area. The allowable tolerance is ±2 °C;

[0063] (5) After the thermal tightening is completed and the electrolytic cell is cooled, tighten the tensioning bolts again for 40 MPa cold tightening (above the minimum bolt load) to control the compression amount of the disc spring;

[0064] After the electrolyzer is fastened, conduct a nitrogen medium airtightness test. There shall be no air leakage at all seals and joints within 60 minutes; maintain the pressure for 24 hours, and the average hourly leakage rate shall not exceed 0.5%.

[0065] After the electrolyzer is turned over and placed horizontally, conduct another airtightness test. The method and acceptance criteria are the same as the above requirements.

[0066] For the electrolyzers completed in the above Examples 1 and 2, their application status is good and their service life is significantly improved.

[0067] The technical means disclosed in the solution of the present invention are not limited to the technical means disclosed by the above technical means, but also include technical solutions composed of any combination of the above technical features.

[0068] Taking the above ideal embodiments of the present invention as inspiration, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A fastening method for an alkaline water electrolysis hydrogen production electrolyzer, characterized in that, It includes the following steps: Step 1: The outside of the electrolytic cell is an insulating sleeve. The two ends of the electrolytic cell are encapsulated with end covers. Assemble the internal structure of the electrolytic cell. Cover the upper pressure plate on its top. Immediately pass 4 tie rods distributed in a cross shape through the connection holes of the two end plates, and connect a tension bolt stretcher to the end of the tie rod passing through the end plate. Seal the electrolytic cell. The tension bolt stretchers are all connected to the distributor through hydraulic pipes. The distributor is connected with a hydraulic pump, and the hydraulic pump is connected to the hydraulic pumping station; Step 2: Pre-tightening: Cold-tighten the tension bolt stretcher until the pressure of the hydraulic pump reaches above the minimum bolt load, clamp the electrolytic cell to prevent the components of the electrolytic cell from moving, and then pass the remaining tie rods; Step 3: Cold-tightening and fastening: Cold-tighten all the tension bolt stretchers until the pressure of the hydraulic pump reaches above the minimum bolt load. During cold-tightening, the tension bolt stretchers are symmetrically pre-tightened, and the tightening sequence is carried out in a cross form, that is, in a diagonal pair distribution. The hydraulic pumping station raises the pressure at intervals of 5-10 MPa until the pressure rises above the calculated minimum bolt load; Step 4: Lock the detent ring and nut inside the tension bolt stretcher, relieve the pressure of the tension bolt stretcher. After the tension bolt stretcher is completely depressurized, then fix the tension bolt stretcher to the tie rod, unlock the detent ring and nut inside the tension bolt stretcher, and then raise the pressure of the tension bolt stretcher until the pressure of the tension bolt stretcher rises above the calculated minimum bolt load; Step 5: Repeat Step 4 until the tie rod is pulled to the predetermined position or the tension bolt stretcher reaches the predetermined pressure; Step 6: Lock the detent ring and nut inside the tension bolt stretcher, relieve the pressure of the tension bolt stretcher, and connect the tension bolt stretcher to the tie rod beside it; Step 7: Repeat Steps 3-5 to complete the cold-tightening and fastening of all tie rods; Step 8: Thermal tightening: Evacuate the electrolytic cell to 0.1-10 kPa. Under vacuum conditions, gradually heat-tighten by gradually increasing the steam temperature in a stepwise manner. At each heat-tightening temperature gradient, perform a thermal tightening. The thermal tightening method is the same as the cold-tightening. Raise the temperature by one more gradient and repeat the thermal tightening again until the temperature rises to the specified temperature and perform the last thermal tightening; Step 9: After the thermal tightening is completed and the electrolytic cell cools down, tighten the tension bolt stretcher again; Step 10: Complete the fastening of the end plate of the electrolytic cell.

2. The fastening method of the alkaline water electrolysis hydrogen production electrolyzer according to claim 1, characterized in that, A number of connection holes are provided on the end plate. A tie rod is inserted into every other connection hole among all the connection holes. There is a tie rod at the symmetric point of each tie rod along the center of the end plate.

3. The fastening method of the alkaline water electrolysis hydrogen production electrolyzer according to claim 1, characterized in that, The heating rate during thermal tightening is 0-10 °C / min, keep warm and constant temperature for 1-10 h, detect the temperature uniformity of each area, and the allowable tolerance is ±2 °C.

4. The fastening method of the alkaline water electrolysis hydrogen production electrolyzer according to claim 3, characterized in that, The pressure value of the hydraulic pump in Step 2 is 30-50 MPa.

5. The fastening method of the alkaline water electrolysis hydrogen production electrolyzer according to claim 1, characterized in that, The pressure value of the hydraulic pump in Step 3 is 50-70 Mpa; the pressure value of the hydraulic pump during the thermal tightening in Step 8 is 50-70 Mpa.

6. The fastening method of the alkaline water electrolysis hydrogen production electrolyzer according to claim 1, characterized in that, In Step 8, finally heat-tighten to 100-150 °C.

7. The fastening method of the alkaline water electrolysis hydrogen production electrolyzer according to claim 1, characterized in that, The pressure value of the hydraulic pump for tightening the tension bolt stretcher again in Step 9 is 30-50 Mpa.

8. The fastening method of the alkaline water electrolysis hydrogen production electrolyzer according to claim 1, characterized in that, Nuts and disc springs are respectively sleeved at both ends of the tie rod, and the disc spring is located between the nut and the end plate.

9. The fastening method of the alkaline water electrolysis hydrogen production electrolyzer according to claim 1, characterized in that, It also includes Step 11: airtightness test: inert gas is pressurized into the electrolytic cell, and within 60 minutes of maintaining the pressure, it is detected that there is no air leakage at all seals and joints. After maintaining the pressure for 24 hours, the average hourly leakage rate does not exceed 0.5%.

10. The fastening method of the alkaline water electrolysis hydrogen production electrolyzer according to claim 9, characterized in that, After the electrolytic cell is turned over and placed horizontally, conduct an airtightness test again, and the test process is as in Step 11.

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