High-pressure hydrogen storage tank and its production process

Abstract

This application relates to the technical field of hydrogen storage, and particularly relates to a high-pressure hydrogen storage tank and its production process. The high-pressure hydrogen storage tank includes an inner tank and an outer tank. The inner tank and the outer tank are in interference fit. The outer tank is provided with a leakage inspection port that penetrates through the outer tank and is used to monitor the leakage of the medium in the inner tank. Through the setting of the outer tank and the use of interference fit, the inner tank and the outer tank can form a better whole, thereby reducing the thickness of the tank body and reducing the production difficulty. At the same time, when the inner tank that is prone to hydrogen embrittlement leaks, there is also the outer tank to block it, and the leakage of the inner tank can be detected through the leakage inspection port. In this way, adjustments can be made in a timely manner. This application has the advantages of reducing the production difficulty and being able to avoid the occurrence of leakage incidents.

Description

Technical Field

[0001] This application relates to the technical field of hydrogen storage, and particularly relates to a high-pressure hydrogen storage tank and its production process. Background Art

[0002] Cylindrical autoclaves, vulcanizing cylinders, liquefied petroleum gas storage tanks, reaction kettles, liquid ammonia storage tanks, high-pressure oxygen chambers, liquefied gas storage tanks, etc. widely used in industrial production departments such as chemical industry, oil refining, petrochemical industry, light industry, pharmaceutical industry, and food industry, including relatively large industrial boiler steam drums and shell-and-tube heat exchanger shells, etc., have a wall thickness of about 6 - 40 mm, and the internal pressure is mostly between 0.3 - 3.0 MPa. Due to the relatively thin wall of these medium- and low-pressure pressure vessel equipment, modern domestic and foreign ones are directly formed by rolling and welding with corresponding steel plates, and the manufacturing is relatively simple and easy.

[0003] However, in the field of hydrogen storage, due to the relatively large internal pressure, usually between 20 - 70 MPa, and in addition, the problem of hydrogen embrittlement will occur during long-term use, resulting in the wall thickness of the hydrogen storage tank reaching about 200 mm, far exceeding the current national pressure vessel material standards. This makes the production of hydrogen storage tanks very difficult, and it is difficult to guarantee the welding quality.

[0004] Among them, the corrosion of the tank body caused by hydrogen embrittlement will cause fatigue and cracks in the metal material. Especially in the case of poor welding quality, leakage accidents are likely to occur, leading to poisoning and explosion accidents. Therefore, the existing treatment method is to conduct regular inspections. This method is not only cumbersome, but these inspections still cannot completely avoid the occurrence of leakage accidents.

[0005] Therefore, it is necessary to design a hydrogen storage tank with low production difficulty and capable of avoiding leakage.

[0006] In order to reduce the production difficulty and avoid the occurrence of leakage events, this application provides a high-pressure hydrogen storage tank in the Summary of the Invention.

[0007] In the first aspect, this application provides a high-pressure hydrogen storage tank, adopting the following technical solution:

[0008] A high-pressure hydrogen storage tank includes an inner tank and an outer tank. The inner tank and the outer tank are in interference fit, and the outer tank is provided with a leakage inspection port penetrating through the outer tank.

[0009] With such a setting, through the setting of the outer tank and the interference fit method, the inner tank and the outer tank can form a better whole, thereby reducing the thickness of the inner wall and reducing the production difficulty. At the same time, when leakage occurs in the inner tank that is prone to hydrogen embrittlement, there is still the outer tank to block it, and the leakage situation of the inner tank can be detected through the leakage inspection port. In this way, adjustments can be made in a timely manner.

[0010] In one embodiment, the interference amount between the inner tank and the outer tank is 1‰ - 2‰.

[0011] With such a setting, on the one hand, the ovality and straightness of the inner and outer tanks can be appropriately adjusted by the interference method, improving the manufacturing accuracy of the container. On the second hand, the inner and outer tanks are closely fitted, improving heat transfer and reducing the temperature difference and temperature stress between the inner tank and the outer tank. On the third hand, the overall collapse strength of the hydrogen storage tank is improved. On the fourth hand, it is possible to avoid problems such as the interference stress reaching the yield strength of the steel due to excessive interference amount, and the occurrence of reheat cracks caused by excessive heating temperature and heating time due to excessive interference amount.

[0012] In one embodiment, the allowable stress of the inner tank is less than that of the outer tank, and the wall thickness of the inner tank is greater than that of the outer tank.

[0013] With such a setting, the inner tank serves as the contact layer, and its life affects the overall service life. Therefore, its thickness needs to be greater than that of the outer tank. At the same time, the outer tank does not come into contact with the medium, providing more room for material selection. When using a material with a greater allowable stress, it can strengthen the allowable stress of the inner tank. In this way, on the premise of meeting the usage requirements, the overall wall thickness of the tank can be reduced, with the overall wall thickness reduced by one - quarter to half, or even more.

[0014] In one embodiment, the material of the inner tank is low - temperature steel 16MDR, and the material of the outer tank is high - strength low - temperature steel 07MnNiMoVDR.

[0015] With such a setting, low - temperature steel 16MDR is a commonly used material for high - pressure hydrogen storage tanks. When using a double - layer structure and the outer tank is made of high - strength low - temperature steel 07MnNiMoVDR, compared with a single - layer low - temperature steel 16MDR, the overall thickness can be reduced by only one - quarter, and the thickness of the low - temperature steel 16MDR of the inner tank can be less than half of the original.

[0016] In one embodiment, the thickness calculation formulas for the inner tank and the outer tank are as follows: where δ1 is the thickness of the inner tank, δ2 is the thickness of the outer tank, p c is the design pressure, D i is the inner diameter of the inner tank, is the allowable stress of the inner tank, is the allowable stress of the outer tank, and Φ is the welding joint coefficient.

[0017] With such a setting, through the above formula, the most reasonable wall thicknesses of the inner tank and the outer tank can be calculated by the method of prediction and verification, ensuring a smaller wall thickness while having a larger combined allowable stress.

[0018] In one embodiment: the inner tank includes an inner cylindrical body and inner hemispherical heads welded to both ends of the inner cylindrical body, and the outer tank includes an outer cylindrical body and outer hemispherical heads welded to both ends of the outer cylindrical body.

[0019] With such a setting, the welded setting of the heads enables the inner and outer tanks to be processed by means of sleeving, making the processing convenient and enabling simple and stable control of the interference amount.

[0020] In one embodiment: the welding positions between the inner cylindrical body and the inner hemispherical heads are staggered from the welding positions between the outer cylindrical body and the outer hemispherical heads, and the weld positions of the inner cylindrical body are staggered from the weld positions of the outer cylindrical body.

[0021] With such a setting, all the welds on the inner cylindrical body and the outer cylindrical body are staggered. In this way, under the double-layer structure, a better pressure-bearing and self-protection effect can be formed, improving the service life of the inner tank.

[0022] In one embodiment: the welding positions of the two inner cylindrical bodies and the inner hemispherical heads are located between the welding positions of the two outer cylindrical bodies and the outer hemispherical heads.

[0023] With such a setting, the outer tank can better play a role in bearing pressure and self-protection for the inner tank.

[0024] Second, the present application provides a production process for a high-pressure hydrogen storage tank, adopting the following technical solutions:

[0025] A production process for a high-pressure hydrogen storage tank includes the following steps:

[0026] S1. Calculate parameters and calculate the wall thicknesses of the inner tank and the outer tank;

[0027] S2. Forming: Calculate the wall thicknesses of the inner tank and the outer tank, then bend the plates with corresponding thicknesses and weld both ends to respectively form an inner cylindrical body and an outer cylindrical body, and then complete the welding of the inner hemispherical heads at both ends of the inner cylindrical body and the welding of the outer hemispherical head at one end of the outer cylindrical body;

[0028] S2. Sleeving: After heating and expanding the outer cylindrical body, insert the unheated inner cylindrical body into the outer cylindrical body, where the insertion of the inner cylindrical body is completed by the self-weight of the inner cylindrical body;

[0029] S3. Heads: After heating and expanding the un-welded outer hemispherical head, sleeve it onto the inner hemispherical head at the exposed end of the inner cylindrical body;

[0030] S4. Welding: After cooling, complete the welding between the outer hemispherical head and the outer cylindrical body.

[0031] With such a setting, on the one hand, the method of using a heating outer sleeve is adopted to achieve an interference fit after sleeving. At the same time, during this process, forced pressing-in is not used, and it can be completed under its own weight, which can effectively reduce or even avoid the generation of axial scratches during the sleeving process and ensure the quality of the inner tank and the outer tank. Brief Description of the Drawings

[0032] Figure 1 is a schematic structural diagram of this embodiment;

[0033] Figure 2 is a partial enlarged view of this embodiment, showing the installation structure of the leakage inspection port.

[0034] In the figure, 100, inner tank; 200, outer tank; 300, inner hemispherical head; 400, outer hemispherical head; 500, manhole; 600, gas inlet and outlet; 700, vent port; 800, drain port; 900, leakage inspection port. Detailed Description of the Embodiment

[0035] The following further describes the present application in detail with reference to the drawings.

[0036] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0037] A high-pressure hydrogen storage tank, as Figure 1 shown, includes an inner tank 100 and an outer tank 200. The inner tank 100 includes an inner cylinder body and inner hemispherical heads 300 welded to both ends of the inner cylinder body. The outer tank 200 includes an outer cylinder body and outer hemispherical heads 400 welded to both ends of the outer cylinder body.

[0038] The welding positions between the inner cylinder body and the inner hemispherical heads 300 and the welding positions between the outer cylinder body and the outer hemispherical heads 400 are arranged staggeredly, and the welding positions between the two inner cylinder bodies and the inner hemispherical heads 300 are located between the welding positions between the two outer cylinder bodies and the outer hemispherical heads 400.

[0039] The weld positions of the inner cylinder body and the weld positions of the outer cylinder body are arranged staggeredly. Here, the weld positions refer to the welding positions during the forming process of the inner cylinder body, that is, the welds formed by welding both ends after bending the steel plate into a cylindrical shape.

[0040] Among them, an interference fit is provided between the inner tank 100 and the outer tank 200, that is, an interference fit is provided between the inner cylinder body and the outer cylinder body, and between the inner hemispherical heads 300 and the outer hemispherical heads 400, and the interference amount is controlled to be 1‰ - 2‰.

[0041] Five nozzle flanges are welded on the hydrogen storage tank, and a manhole 500, a gas inlet / outlet 600, a vent 700, a drain 800 and a leak inspection port 900 are respectively arranged corresponding to the nozzle flanges. The manhole 500 is arranged on one of the outer hemispherical heads 400. The gas inlet / outlet 600, the vent 700 and the leak inspection port 900 are all arranged on the top of the outer tank 200, and the drain 800 is arranged at the bottom of the outer tank 200.

[0042] Among them, the manhole 500, the gas inlet / outlet 600, the vent 700 and the drain 800 all penetrate through the inner tank 100 and the outer tank 200 and are communicated with the inside of the inner tank 100. The nozzle flanges corresponding to the manhole 500, the gas inlet / outlet 600, the vent 700 and the drain 800 are welded to the inner tank 100 and the outer tank 200 at the same time. Refer to Figure 2 , the nozzle flange corresponding to the leak inspection port 900 is only welded to the outer tank 200, that is, the leak inspection port 900 is arranged to penetrate only through the outer tank 200.

[0043] The wall thickness of the inner tank 100 is greater than that of the outer tank 200, and the allowable stress of the inner tank 100 is less than that of the outer tank 200. In this embodiment, the material of the inner tank 100 is low-temperature steel 16MDR, and the material of the outer tank 200 is high-strength low-temperature steel 07MnNiMoVDR.

[0044] In this embodiment, the total thickness calculation formula of the inner tank 100 and the outer tank 200 is:

[0045]

[0046] In the formula, δ1—the thickness of the inner tank;

[0047] δ2—the thickness of the outer tank.

[0048] p c —Design pressure;

[0049] D i —Inner diameter of the inner tank;

[0050] Φ—Weld joint coefficient;

[0051] —Allowable stress of the inner tank;

[0052] —Allowable stress of the outer tank.

[0053] The production process of the high-pressure hydrogen storage tank includes the following steps:

[0054] S1. Forming: Calculate the wall thicknesses of the inner tank 100 and the outer tank 200 through formulas. When the calculated wall thickness is not an integer, round it up and add 1. For example, when the calculated wall thickness of the inner tank 100 is 89.1 mm and that of the outer tank 200 is 48.8 mm, the final wall thicknesses of the inner tank 100 and the outer tank 200 are set to 90 mm and 49 mm respectively.

[0055] Bend the plates with corresponding thicknesses and then weld the two ends to form the inner cylinder and the outer cylinder respectively. Then, weld the inner hemispherical heads 300 at both ends of the inner cylinder, and weld the outer hemispherical head 400 at one end of the outer cylinder. Among them, the connecting pipe flange corresponding to the leakage inspection port 900 is also welded to the outer tank 200 in this step.

[0056] S2. Sleeving: After heating and expanding the outer cylinder, insert the unheated inner cylinder into the outer cylinder. Among them, the insertion of the inner cylinder is completed by the self-weight of the inner cylinder, and it is not allowed to use external force to forcibly insert it.

[0057] S3. Head fitting: After heating and expanding the unwelded outer hemispherical head 400, fit it onto the inner hemispherical head 300 at the exposed end of the inner cylinder.

[0058] S4. Welding: After cooling, complete the welding between the outer hemispherical head 400 and the outer cylinder. In this step, simultaneously complete the welding of the connecting pipe flanges corresponding to the manhole 500, the gas inlet and outlet 600, the vent port 700, and the drain port 800.

[0059] The embodiments of this specific implementation manner are all preferred embodiments of this application, and do not limit the protection scope of this application accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A high-pressure hydrogen storage tank, characterized in that: It includes an inner tank (100) and an outer tank (200). There is an interference fit between the inner tank (100) and the outer tank (200). A leakage inspection port (900) is provided on the outer tank (200) and penetrates through the outer tank (200) for monitoring the leakage of the medium in the inner tank (100). The thickness calculation formulas for the inner tank (100) and the outer tank (200) are as follows: ; where is the thickness of the inner tank, is the thickness of the outer tank, is the design pressure, is the inner diameter of the inner tank, is the allowable stress of the inner tank, is the allowable stress of the outer tank, is the welding joint coefficient; The production process of the high-pressure hydrogen storage tank includes the following steps: S1. Calculate parameters and calculate the wall thicknesses of the inner tank (100) and the outer tank (200). S2. Forming: Calculate the wall thicknesses of the inner tank (100) and the outer tank (200), then bend the plates with corresponding thicknesses and weld the two ends to respectively form an inner cylinder and an outer cylinder. Then, weld the inner hemispherical heads (300) at both ends of the inner cylinder, and weld the outer hemispherical head (400) at one end of the outer cylinder. S2. Sleeving: After heating and expanding the outer cylinder, sleeving the unheated inner cylinder into the outer cylinder. Among them, the sleeving of the inner cylinder is completed by the self-weight of the inner cylinder. S3. Head: After heating and expanding the un-welded outer hemispherical head (400), sleeving it onto the inner hemispherical head (300) at the exposed end of the inner cylinder. S4. Welding: After cooling, complete the welding between the outer hemispherical head (400) and the outer cylinder.

2. The high-pressure hydrogen storage tank according to claim 1, wherein: The interference amount between the inner tank (100) and the outer tank (200) is 1‰ - 2‰.

3. The high-pressure hydrogen storage tank according to claim 1, characterized in that: The allowable stress of the inner tank (100) is less than that of the outer tank (200), and the wall thickness of the inner tank (100) is greater than that of the outer tank (200).

4. The high-pressure hydrogen storage tank according to claim 3, characterized in that: The material of the inner tank (100) is low-temperature steel 16MDR, and the material of the outer tank (200) is high-strength low-temperature steel 07MnNiMoVDR.

5. The high-pressure hydrogen storage tank according to claim 1, characterized in that: The inner tank (100) includes an inner cylinder and inner hemispherical heads (300) welded at both ends of the inner cylinder. The outer tank (200) includes an outer cylinder and outer hemispherical heads (400) welded at both ends of the outer cylinder.

6. The high-pressure hydrogen storage tank according to claim 5, characterized in that: The welding positions between the inner cylinder and the inner hemispherical heads (300) are arranged staggeredly from the welding positions between the outer cylinder and the outer hemispherical heads (400), and the weld positions of the inner cylinder are arranged staggeredly from the weld positions of the outer cylinder.

7. The high-pressure hydrogen storage tank according to claim 6, wherein: The welding positions of the two inner cylinders and the inner hemispherical heads (300) are located between the welding positions of the two outer cylinders and the outer hemispherical heads (400).

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