Hydrogen conveying pipe and manufacturing method thereof

Abstract

The invention discloses a hydrogen conveying pipe and a manufacturing method thereof, and the hydrogen conveying pipe comprises an inner pipe which is a stainless steel pipe with a welding seam; at least one groove is formed in the outer wall of the body, the groove comprises a strip-shaped groove and / or an annular groove, the depth of the groove is 0.3-0.5 mm, and the width of the cross section of the groove is smaller than or equal to 2 mm; the outer pipe is a carbon steel pipe, and the inner wall of the outer pipe is compounded with the outer wall of the inner pipe, so that the groove forms a gas channel between the inner pipe wall and the outer pipe wall; the outer pipe is provided with an outlet, and the outlet is communicated with the gas channel and the outside. The hydrogen conveying pipe is designed into a composite pipe form, and the grooves are formed in the outer wall of the inner pipe, so that a gas channel is formed between the inner pipe and the outer pipe, on one hand, the strength of the inner pipe is enhanced, on the other hand, hydrogen permeating the inner pipe wall is exhausted, and pipeline damage is prevented. The pipe diameter of the hydrogen long-distance pipeline is increased to 1422 mm from the maximum 610 mm, the hydrogen transportation amount is greatly increased, the use amount of stainless steel is limited, and the cost of the pipeline is saved to a great extent.

Description

Technical Field

[0001] The present invention relates to the technical field of gas storage and transportation, and particularly relates to a hydrogen transportation pipe and a manufacturing method thereof. Background Art

[0002] As a kind of new energy, hydrogen energy, as a clean energy, has attracted much attention in the industrial circle. When hydrogen is used in various technological processes, it mostly needs to be transported through pipelines. When transporting through pipelines, seamless steel pipes are required. As a high-pressure fluid of small molecules, if a carbon steel pipe with a weld is used for hydrogen, it is prone to hydrogen corrosion damage, resulting in hydrogen leakage and potential safety hazards. Although stainless steel has a better effect on dealing with hydrogen corrosion, on the one hand, its cost is expensive, and on the other hand, its yield strength is not high, and it is prone to burst under high pressure, also having potential safety hazards.

[0003] However, in the prior art, the types of seamless steel pipes that can be rolled are limited, and their nominal diameter ≤ 610 mm. Moreover, to avoid hydrogen corrosion, seamless steel pipes can only select steels with X52 and lower strength (the higher the strength, the greater the probability of hydrogen corrosion). This makes the maximum pressure that can be borne inside the pipe not exceed 6 MPa, and it is necessary to further increase the wall thickness, which results in limited hydrogen transportation volume. Therefore, how to increase the hydrogen transportation volume has become a problem to be solved in this field. Summary of the Invention

[0004] The purpose of the present invention is to increase the flow rate of the hydrogen transportation pipeline while ensuring safety.

[0005] To achieve the above purpose, the present invention provides a hydrogen transportation pipe, comprising: An inner pipe, which is a stainless steel pipe with a weld; at least one groove is provided on its outer wall, and the groove includes a strip-shaped groove and / or an annular groove; An outer pipe, which is a carbon steel pipe; its inner wall is compounded with the outer wall of the inner pipe, so that the groove forms a gas channel between the inner and outer pipe walls; an outlet is provided on the outer pipe, and the outlet communicates the gas channel with the outside.

[0006] Preferably, the strip-shaped groove is consistent with the axial direction of the hydrogen transportation pipe and penetrates the axial direction of the hydrogen transportation pipe.

[0007] Preferably, 4 to 8 strip-shaped grooves are provided, and the strip-shaped grooves are evenly distributed in the circumferential direction.

[0008] Preferably, a plurality of annular grooves are provided, which are evenly distributed in the axial direction, and the distance between adjacent annular grooves is 1 to 3 m.

[0009] Preferably, the annular groove is perpendicular to the axial direction of the hydrogen transportation pipe.

[0010] Preferably, the strip-shaped groove is a spiral groove.

[0011] Preferably, the spiral groove includes a left spiral groove and a right spiral groove.

[0012] Preferably, the depth of the groove is 0.3 - 0.5 mm, and the cross-sectional width ≤ 2 mm.

[0013] The present invention also discloses a manufacturing method of the above hydrogen transportation pipe, which includes the following steps: S1, manufacturing the inner pipe and the outer pipe; S2, after inserting the tube expander into the inner pipe, rolling the groove on the inner pipe to prevent damage to the inner pipe during the rolling process; S3, opening the outlet on the outer pipe; S4, the tube expander still remains in the inner pipe, and the inner pipe is sleeved in the outer pipe and continues to expand, so as to composite the inner pipe and the outer pipe.

[0014] The beneficial effects of the present invention include: by designing the hydrogen transportation pipe in the form of a composite pipe and setting grooves on the outer wall of the inner pipe, a gas channel is formed between the inner and outer pipes. On the one hand, the strength of the inner pipe is enhanced, and on the other hand, the hydrogen permeating through the inner pipe wall is discharged to prevent pipeline damage. This enables the diameter of the long-distance hydrogen transportation pipeline to be increased from the previous maximum of 610 mm to 1422 mm, and the maximum pressure that can be withstood is also increased from 6 MPa to more than 10 MPa. While ensuring the safety of pipeline transportation, the hydrogen transportation volume is greatly improved, and the amount of stainless steel used is limited, saving the cost of the pipeline to a large extent. Description of the Drawings

[0015] Figure 1 It is a partial schematic diagram of Embodiment 1 of the hydrogen transportation pipe of the present invention; Figure 2 It is a cross-sectional view of Embodiment 1 of the hydrogen transportation pipe of the present invention; Figure 3 It is a wall surface diagram of the inner pipe wall of Embodiment 1 of the hydrogen transportation pipe of the present invention; Figure 4 It is a wall surface diagram of the inner pipe wall of Embodiment 2 of the hydrogen transportation pipe of the present invention; Reference numerals: 1 - inner pipe; 11 - strip-shaped groove; 12 - annular groove; 13 - left spiral groove; 14 - right spiral groove; 2 - outer pipe; 21 - outlet. Detailed Embodiments

[0016] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0017] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "inner", "outer", "top", "bottom", etc. is based on Figure 1 the orientation or positional relationship shown, and is only for the convenience of describing the present invention 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 invention.

[0018] In addition, the terms "first" and "second" are only used for descriptive purposes, and do not refer to the limitation of time sequence, quantity, or importance. It cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features, but only for distinguishing one technical feature in the present technical solution from another. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more, unless otherwise clearly and specifically defined. Similarly, the limiting terms similar to "a" appearing herein do not refer to the limitation of quantity, but describe technical features that have not appeared previously. Similarly, unless it is a noun modified by a specific quantity quantifier, it should be regarded as including both the singular form and the plural form herein. In this technical solution, it may include a single one of such technical features or a plural number of such technical features. Similarly, the modifying terms such as "about" and "approximately" appearing before a numeral usually include the present number, and their specific meanings should be understood in combination with the context.

[0019] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0020] Unless clearly indicated as mutually exclusive, each aspect or embodiment defined herein can be combined with any other one or more aspects or one or more embodiments. In particular, any feature indicated as preferred or advantageous can be combined with any other feature indicated as preferred or advantageous.

[0021] The present invention discloses a hydrogen transport pipe, as Figures 1 to 4 shown. The hydrogen transport pipe is a metal composite pipe formed by compounding an inner pipe 1 and an outer pipe 2. The inner pipe 1 is a stainless steel pipe with a relatively low yield strength. The outer pipe 2 provides comprehensive support for the wall of the inner pipe 1 to prevent the inner pipe 1 from being damaged under high pressure.

[0022] At least one groove is provided on the outer wall of the inner pipe 1. The groove includes a strip-shaped groove 11 and / or an annular groove 12. Since small molecule gases such as hydrogen or helium have small particles themselves, and the pressure in the transport pipe often exceeds 10 MPa, this results in part of the hydrogen being likely to penetrate the pipe wall in the form of hydrogen atoms under high pressure. If the gas is allowed to be discharged from the pipe wall to the atmosphere, on the one hand, it will cause waste of the gas, and on the other hand, if the outer pipe 2 of the hydrogen transport pipe is not stainless steel and the ordinary carbon steel has relatively large internal voids, hydrogen atoms are likely to combine inside the carbon steel, thereby causing hydrogen corrosion to the carbon steel and generating bubbles, thus causing damage to the outer pipe 2 and posing a safety hazard. Therefore, at least one groove can be pressed on the outer wall of the inner pipe 1, and the groove forms a gas channel between the inner and outer pipe walls. The gas pressure in the gas channel is close to normal pressure. The outer pipe 2 is provided with an outlet 21, and the gas channel is connected to the outside through the outlet 21. Because there will be a tiny gap between the inner and outer pipes no matter how they are compounded, as long as the pressure is normal or close to normal, the gas in the transport pipe will enter the gas channel after passing through the wall of the inner pipe 1, without worrying about the gas continuing to pass through the wall of the outer pipe 1.

[0023] The groove can have different arrangement forms. In some embodiments, the groove simultaneously includes a plurality of strip-shaped grooves 11 and a plurality of annular grooves 12. The strip-shaped grooves 11 are axially opened and are consistent with the axial direction of the hydrogen transport pipe and penetrate the axial direction of the hydrogen transport pipe. The annular grooves 12 are circumferentially opened, that is, completely perpendicular to the axial direction of the hydrogen transport pipe. The groove in this form is relatively easy to press.

[0024] In some embodiments, the strip-shaped grooves 11 penetrate the length direction of the hydrogen transport pipe and are evenly distributed in the circumferential direction, and the annular grooves 12 are evenly distributed in the axial direction, so that the gas channels are evenly distributed between the inner and outer pipe walls, thereby making the gas flow more stable in the gas channels.

[0025] In some embodiments, 4 to 8 strip-shaped grooves 11 are provided, and the spacing between adjacent annular grooves 12 is 1 to 3 m, both of which control the density of the gas channel arrangement. If the arrangement of the gas channels is too sparse, the resistance for the gas to enter the gas channels from between the inner and outer pipe walls in some areas will increase; if the arrangement of the gas channels is too dense, the pressing process will be more complex and time-consuming.

[0026] In some embodiments, the strip-shaped groove 11 is a spiral groove. Further, the spiral groove includes a left spiral groove 13 and a right spiral groove 14. Among them, the left spiral groove 13 means that when the axis is vertical, the visible part of the spiral groove rises from right to left, which is called a left spiral; otherwise, it is the right spiral groove 14. Further, the pitches of the left spiral groove 13 and the right spiral groove 14 are equal; this can also make the gas channels more evenly distributed between the inner and outer pipe walls. In this form, it is even not necessary to press the strip-shaped groove 11 in the axial direction. Just rotate the inner pipe 1 while pressing the spiral groove, which is more convenient.

[0027] In some embodiments, the depths of both the strip-shaped groove 11 and the annular groove 12 are 0.3 to 0.5 mm. If the depth is too shallow, it may be less than the error generated during the roll-pressing of the groove, resulting in blockage of some areas of the gas channel, thereby affecting the discharge of the gas passing through the inner pipe wall; if the groove is too deep, the mechanical properties of the inner pipe 1 will be damaged relatively greatly, and the inner pipe 1 may be damaged.

[0028] Since the gas passing through the inner pipe 1 wall is discharged from the gas channel and will not continue to pass through the outer pipe 2, there is no need to consider the risk of hydrogen corrosion of the outer pipe 2. The outer pipe 2 can be a carbon steel pipe. The carbon steel pipe is cheap per unit mass and has a high yield strength, which is obviously more suitable than using a double-layer stainless steel pipe. According to the existing technology, the maximum nominal diameter of the carbon steel pipe can reach 1422 mm, which can meet the transportation of a large amount of hydrogen.

[0029] The present invention also discloses a manufacturing method of the hydrogen transportation pipe, which includes the following steps: S1, manufacturing the inner pipe and the outer pipe; S2, after inserting the expanding tool into the inner pipe, rolling the groove on the inner pipe to prevent damage to the inner pipe during the rolling process; S3, opening the outlet on the outer pipe; S4, the expanding tool still remains in the inner pipe, and the inner pipe is sleeved outside the outer pipe and continues to expand, so as to compound the inner pipe and the outer pipe.

[0030] For the design scheme of the groove, reference can be made to the following embodiments.

[0031] Embodiment 1

[0032] AsFigures 1 to 3 As shown, the grooves on the outer wall of the inner tube of the hydrogen transport pipe include several strip-shaped grooves 11 and several annular grooves 12. The strip-shaped grooves 11 are axially formed, consistent with the axial direction of the hydrogen transport pipe, and penetrate the axial direction of the hydrogen transport pipe; the strip-shaped grooves 11 penetrate the length direction of the hydrogen transport pipe and are evenly distributed in the circumferential direction, with 4 to 8 grooves formed. The annular grooves 12 are circumferentially formed, completely perpendicular to the axial direction of the hydrogen transport pipe, and are evenly distributed in the axial direction. The distance between adjacent annular grooves 12 is 1 to 3 m. The several strip-shaped grooves 11 and several annular grooves 12 together form a gas channel between the inner and outer tubes; the outer tube 2 is provided with an outlet 21, and the gas channel communicates with the outside through the outlet 21.

[0033] Example 2

[0034] As Figure 4 shown, the grooves on the outer wall of the inner tube of the hydrogen transport pipe only include spiral grooves, and the spiral grooves include a left spiral groove 13 and a right spiral groove 14. The left spiral groove 13 and the right spiral groove 14 have equal pitches and together form a gas channel between the inner and outer tubes; the outer tube 2 is provided with an outlet 21, and the gas channel communicates with the outside through the outlet 21.

[0035] In summary, the present invention designs the hydrogen transport pipe in the form of a composite pipe and sets grooves on the outer wall of the inner tube 1, so as to form a gas channel between the inner and outer tubes. On the one hand, the strength of the inner tube is enhanced, and on the other hand, the hydrogen that penetrates the inner tube wall is discharged to prevent pipeline damage. This enables the diameter of the long-distance hydrogen pipeline to be increased from the previous maximum of 610 mm to 1422 mm, and the maximum pressure that can be withstood is also increased from 6 MPa to above 10 MPa. While ensuring the safety of pipeline transportation, the hydrogen transportation volume is greatly increased, and the amount of stainless steel used is limited, saving the cost of the pipeline to a great extent.

[0036] Although the content of the present invention has been introduced in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the present invention. After those skilled in the art have read the above content, various modifications and substitutions to the present invention will be obvious. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims

1. A hydrogen transport pipe, characterized in that, Comprising: An inner tube, which is a stainless steel tube with a weld seam; at least one groove is provided on its outer wall, and the groove includes a strip-shaped groove and / or an annular groove; An outer tube, which is a carbon steel tube; its inner wall is compounded with the outer wall of the inner tube, so that the groove forms a gas channel between the inner and outer tube walls; the outer tube is provided with an outlet, and the outlet communicates the gas channel with the outside.

2. The hydrogen transport pipe according to claim 1, characterized in that, The strip-shaped groove is consistent with the axial direction of the hydrogen transport tube and penetrates the axial direction of the hydrogen transport tube.

3. The hydrogen transport pipe according to claim 2, characterized in that, 4 to 8 of the strip-shaped grooves are opened, and the strip-shaped grooves are evenly distributed in the circumferential direction.

4. The hydrogen transport pipe according to claim 1, wherein A number of the annular grooves are opened and evenly distributed in the axial direction, and the distance between adjacent annular grooves is 1 to 3 m.

5. The hydrogen transport pipe according to claim 1, characterized in that, The annular groove is perpendicular to the axial direction of the hydrogen transport tube.

6. The hydrogen transport pipe according to claim 1, characterized in that, The strip-shaped groove is a spiral groove.

7. The hydrogen transport pipe according to claim 6, wherein, The spiral groove includes a left spiral groove and a right spiral groove.

8. The hydrogen transportation pipe according to claim 1, characterized in that, The depth of the groove is 0.3 to 0.5 mm, and the cross-sectional width ≤ 2 mm.

9. The manufacturing method of the hydrogen transport tube according to any one of claims 1 to 8, which comprises the following steps: S1, manufacturing the inner tube and the outer tube; S2, after inserting the expanding tool into the inner tube, rolling the groove on the inner tube to prevent damage to the inner tube during the rolling process; S3, opening the outlet on the outer tube; S4, the expanding tool still remains in the inner tube, and the inner tube is sleeved in the outer tube and continues to expand, so as to compound the inner tube with the outer tube.

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