Corrosion inhibitor self-protection type hydrogen embrittlement-resistant pipe cleaner for hydrogen-doped pipeline

Abstract

The utility model relates to a self-protection type hydrogen embrittlement-resistant pipe cleaner for a hydrogen-doped pipeline through a corrosion inhibitor. The corrosion inhibitor self-protection type hydrogen embrittlement-resistant pipe cleaner for the hydrogen-doped pipeline is low in cost, long in service life and good in hydrogen embrittlement resistance. The corrosion inhibitor self-protection type hydrogen embrittlement resisting pipe cleaner for the hydrogen-doped pipeline comprises a guiding pipe cleaner, a pre-filming pipe cleaner and a driving pipe cleaner. A first supporting disc sleeves the periphery of the pre-filming pipe cleaner, the pre-filming pipe cleaner comprises a head part, a cavity part and a tail part, the first supporting disc sleeves one end of the cavity part, the head part is arranged on the surface of the first supporting disc and is connected with the cavity part, a first etchant channel and a second etchant channel are arranged in the head part, one end of the first etchant channel is communicated with the cavity part, and the other end of the first etchant channel is communicated with the tail part. One end of the second etchant channel is communicated with the first etchant channel, the other end of the second etchant channel is communicated with the outside, and a nozzle is arranged at a port of the second etchant channel; the other end of the cavity part is fixedly connected with the tail part, and a third etching agent channel is arranged in the tail part.

Description

Technical Field

[0001] This utility model relates to a pipeline cleaning device, and more particularly to a hydrogen embrittlement resistant pipeline cleaning device for use in hydrogen-containing pipelines, which is self-protected by a corrosion inhibitor. Background Technology

[0002] In China, most industrial gas and petroleum products are transported through safe and reliable pipelines. To ensure transportation efficiency and prevent pipelines from being blocked or corroded by impurities, regular pipeline cleaning using a pipeline pig is an essential task.

[0003] Traditional pipeline pigs (such as polyurethane cup pigs and straight plate pigs) perform well in pure natural gas pipelines, but they face serious hydrogen embrittlement problems in hydrogen-blended environments, specifically manifested as follows:

[0004] 1. Degradation of carbon steel components (such as guide frames and support wheels): Hydrogen atoms penetrate into the metal grain boundaries, leading to brittle fracture and a 50%-80% decrease in fatigue life (ASTM F1624 standard test).

[0005] 2. Elastomer seals (such as polyurethane cups): Hydrogen causes swelling and hardening, reducing sealing performance and increasing wear rate by 3-5 times (NACE TM0198-2018 data).

[0006] 3. Welded joints: The risk of hydrogen-induced cracking (HIC) is significantly increased, especially in high-stress areas (such as pig skeleton connections).

[0007] 4. Increased hydrogen pollution: The reducing properties of hydrogen promote the conversion of Fe3O4 to Fe2O3 in the pipeline, producing more loose corrosion products. The cleaning frequency needs to be increased by 2-3 times compared to pure natural gas pipelines (DNV-RP-F112 specification).

[0008] 5. Hydrogen safety management requirements: Residual hydrogen mixed with air can easily form explosive gases (explosion limits 4%-75%), and pipeline cleaning is a key means to eliminate hydrogen accumulation. Utility Model Content

[0009] To solve the above-mentioned technical problems, this utility model provides a low-cost, long-life, and hydrogen embrittlement-resistant pipeline corrosion inhibitor self-protective anti-hydrogen embrittlement pig for hydrogen-doped pipelines.

[0010] This utility model discloses a self-protective anti-hydrogen embrittlement pig for hydrogen-doped pipelines, comprising a guiding pig, a pre-filming pig, and a driving pig. The pre-filming pig is surrounded by a first support disc for support. The pre-filming pig includes a head, a hollow cavity, and a tail. The first support disc is fitted onto one end of the cavity. The head is disposed on the surface of the first support disc and connected to the cavity. The head contains a first etching channel and a second etching channel. One end of the first etching channel communicates with the cavity, and the other end communicates with the outside. One end of the second etching channel communicates with the first etching channel, and the other end communicates with the outside and has a nozzle at its port. The other end of the cavity is fixedly connected to the tail. The tail contains a third etching channel, one end of which communicates with the cavity, and the other end communicates with the outside.

[0011] This utility model discloses a self-protective anti-hydrogen embrittlement pipeline cleaning device with a corrosion inhibitor for hydrogen-doped pipelines, wherein multiple first and second corrosion inhibitor channels are provided and correspond one-to-one.

[0012] This utility model discloses a self-protective anti-hydrogen embrittlement pig for hydrogen-doped pipelines, wherein the pre-filming pig is further fitted with a second support disc on its outer periphery, and the second support disc is fitted at the other end of the cavity.

[0013] This utility model discloses a self-protective anti-hydrogen embrittlement pipeline cleaning device with a corrosion inhibitor for hydrogen-doped pipelines, wherein both the first support disc and the second support disc are provided with a rubber cup.

[0014] This utility model discloses a self-protective anti-hydrogen embrittlement pig for hydrogen-doped pipelines, wherein the guiding pig is a foam pig.

[0015] This utility model discloses a self-protective anti-hydrogen embrittlement pig for hydrogen-doped pipelines, wherein the driving pig is also a foam pig.

[0016] The difference between this utility model and the prior art is that the anti-hydrogen embrittlement pig in this utility model adopts a combination of three pigs. The guiding pig and the driving pig adopt foam pigs, and the pre-filming pig adopts a pig that can store and spray corrosion inhibitors by combining the head cavity and the tail. The driving pig is driven by gas, which in turn drives the pre-filming pig to form a pressure difference. The pressure difference is used to spray the corrosion inhibitor from the head of the pre-filming pig onto the top wall of the pipeline. The corrosion inhibitor in the cavity is discharged into the pipeline by the siphon effect and the pressure difference, so as to perform a long-term pre-filming on the pipeline and form a protective layer on the surface of the pre-filming pig for self-protection through the atomized corrosion inhibitor.

[0017] This utility model discloses a self-protective anti-hydrogen embrittlement pipeline cleaning device with a corrosion inhibitor for hydrogen-doped pipelines, which includes at least the following beneficial effects:

[0018] (1) It can pre-film the inner top wall of the pipeline to ensure that the pre-filming is more sufficient; the corrosion inhibitor is atomized through the nozzle, and the atomized corrosion inhibitor falls onto the surface of the pig to effectively protect the pig and prevent a series of hydrogen embrittlement problems, thereby extending its service life.

[0019] (2) The multi-pipe and multi-nozzle configuration can increase the spray range and ensure that the corrosion inhibitor fully covers the inner wall of the pipe. On the other hand, it can increase the spray volume and ensure that enough corrosion inhibitor falls on the surface of the pre-filming pig, thus enhancing the self-protection effect.

[0020] (3) This anti-hydrogen embrittlement pig is compatible with existing pipeline pigging systems, with relatively low retrofit costs. At the same time, the corrosion inhibitor can be recycled and reused, reducing operation and maintenance costs.

[0021] The present invention will be further described below with reference to the accompanying drawings. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural diagram of the pre-filming pig in this utility model;

[0023] Figure 2 This is a front view of the pre-filming pig in this utility model;

[0024] Figure 3 This is a sectional view of the main view of the pre-filming pig in this utility model;

[0025] Figure 4 This is a right view of the pre-filming pig in this utility model;

[0026] Figure 5 This is a left view of the pre-filming pig in this utility model;

[0027] Figure 6 This is a schematic diagram of a self-protective anti-hydrogen embrittlement pipeline cleaning device for hydrogen-doped pipelines, which is installed in the pipeline according to the present invention.

[0028] Figure label:

[0029] 01-Guided pig; 11-Foam pig; 02-Pre-film pig; 21-Head; 211-First etchant channel; 212-Second etchant channel; 213-Nozzle; 22-Cavity; 23-Tail; 231-Third etchant channel; 24-First support disc; 25-Second support disc; 26-Cup; 03-Drive pig; 04-Pipeline. Detailed Implementation

[0030] like Figure 1 , 2As shown in Figures 3 and 6, this utility model discloses a self-protective anti-hydrogen embrittlement pipeline cleaning device for hydrogen-doped pipelines, comprising a guiding cleaning device 01, a pre-filming cleaning device 02, and a driving cleaning device 03. The pre-filming cleaning device 02 is surrounded by a first support disc 24 for support. The pre-filming cleaning device 02 includes a head 21, a hollow cavity 22, and a tail 23. The first support disc 24 is fitted onto one end of the cavity 22. The head 21 is disposed on the surface of the first support disc 24 and connected to the cavity 22. A first etchant is disposed inside the head 21. The first etching channel 211 is connected to the cavity 22 at one end and to the outside at the other end. The second etching channel 212 is connected to the first etching channel 211 at one end and to the outside at the other end, and a nozzle 213 is provided at the port. The other end of the cavity 22 is fixedly connected to the tail 23. A third etching channel 231 is provided in the tail 23. One end of the third etching channel 231 is connected to the cavity 22 and the other end is connected to the outside.

[0031] The hydrogen embrittlement-resistant pig of this utility model is composed of three pigs. The front guide pig 01 is used to guide and remove impurities on the inner wall of the pipeline 04 and accumulated in the pipeline 04. At the same time, it works with the pre-filming pig 02 in the pipeline 04 to form a corrosion inhibitor slug.

[0032] The middle pre-filming pig 02 is used to pre-film the inner wall of the pipeline 04 and deeply remove impurities accumulated on the inner wall and inside the pipeline 04. The rear drive pig 03 is used to push the pre-filming pig 02 and the guide pig 01 to move, and works with the guide pig 01 to provide initial protection for the pre-filming pig 02 and further remove impurities inside the pipeline 04.

[0033] The first support disc 24 serves two purposes: supporting the pre-filming pig 02 and connecting it to the head 21. The first support disc 24 is bolted or welded to the right end of the cavity 22 of the pre-filming pig 02. The first support disc 24 has through holes evenly arranged circumferentially, and the head 21 of the pre-filming pig 02 also has corresponding through holes. Bolts are used to firmly fix the head 21 to the right surface of the first support disc 24 through these through holes, thus sealing the head 21 to the right end of the cylindrical cavity 22. The tail 23 is then firmly fixed to the left end of the cavity 22 by bolts or welding, sealing it to the cavity 22 as well. Therefore, the head 21, cavity 22, and tail 23 together constitute the overall structure of the pre-filming pig 02.

[0034] The cavity 22 is used to store corrosion inhibitor. The left end of the first corrosion inhibitor channel 211 is connected to the cavity 22 and the port is flush with the bottom end of the cavity 22. The right end extends downward through the head 21 and connects to the outside. The corrosion inhibitor in the cavity 22 is guided to the pipe 04 through the first corrosion inhibitor channel 211 by using the siphon effect, ensuring that the corrosion inhibitor in the cavity 22 can flow out into the pipe 04 through the first corrosion inhibitor channel 211.

[0035] Since pipeline 04 carries hydrogen-blended natural gas, the characteristics of hydrogen atoms can cause serious hydrogen embrittlement problems for the pig. For example, hydrogen atoms can penetrate into the metal grain boundaries, leading to brittle fracture and reduced fatigue life of the pig; elastomeric seals (such as polyurethane cup 26) can swell and harden, reducing sealing performance and accelerating wear rate; and cracks can appear at welded joints inside the pig or pipeline 04, especially in high-stress areas (such as the pig skeleton connection). The lower end of the second corrosion channel 212 is connected to the first corrosion channel 211, and the upper end obliquely extends upward through the head 21 to connect with the outside. A nozzle 213 for spraying corrosion inhibitor is installed at the upper end port. The corrosion inhibitor is atomized through the nozzle 213. On the one hand, it can pre-film the inner top wall of the pipeline 04 to ensure a more thorough pre-filming. On the other hand, the corrosion inhibitor is atomized through the nozzle 213 and falls onto the surface of the pig, effectively protecting the pig and preventing a series of hydrogen embrittlement problems. In addition, this anti-hydrogen embrittlement pig is compatible with the existing pipeline 04 pig launching and receiving system. It does not require infrastructure modification and can directly replace traditional pig operations, saving costs and improving economic efficiency.

[0036] The third etchant channel 231 is used to inject the etchant inhibitor into the cavity 22 and balance the air pressure in the cavity 22. It is preferably L-shaped, with one end extending upward through the tail 23 and the side wall of the cavity 22 to communicate with the outside, and the other end extending to the right through the tail 23 to communicate with the cavity 22, ensuring that the etchant inhibitor in the cavity 22 will not flow out from the third etchant channel 231 and maintaining the maximum volume of the cavity 22.

[0037] In operation, the guiding pig 01 is first placed into the receiving and launching tube, and then a certain amount of corrosion inhibitor is injected into the receiving and launching tube. Next, a certain amount of corrosion inhibitor is injected into the cavity 22 of the pre-filming pig 02 through the third corrosion inhibitor channel 231, and the pre-filming pig 02 is placed into the receiving and launching tube. Finally, the driving pig 03 is placed in. A corrosion inhibitor sluice with a certain degree of sealing is formed between the pre-filming pig 02 and the guiding pig 01. The guiding pig 01 and the driving pig 03 provide initial protection for the pre-filming pig 02, reducing the impact of hydrogen-containing natural gas on its hydrogen embrittlement. The anti-hydrogen embrittlement pig is introduced into the normally supplied gas pipeline 04 through the receiving and launching system. The gas pressure behind the anti-hydrogen embrittlement pig is greater than that in front of it. Under the action of the pressure difference between the front and rear, the anti-hydrogen embrittlement pig can move from back to front. During the movement, the gas propels the pig 03, which in turn propels the pre-filming pig 02 forward within the pipeline 04. As the pre-filming pig 02 advances, it continuously squeezes the corrosion inhibitor slug at the bottom of the pipeline 04, causing its liquid level to rise until it flows into the first corrosion channel 211 and then into the second corrosion channel 212. The liquid is then atomized and sprayed upward through the nozzle 213 to pre-film the top wall of the pipeline 04. Simultaneously, due to pits or weld beads on the inner wall of the pipeline 04, some of the gas driving the rear end of the pig 03 flows into its front end through the gap. At this time, the gas flows into the cavity 22 from the third corrosion channel 231, creating a downward pressure on the corrosion inhibitor in the cavity 22. On the one hand, this downward pressure can force the corrosion inhibitor in the cavity 22 out to the first corrosion channel 211 and flow through the second corrosion channel 212 before being sprayed out through the nozzle 213. On the other hand, this downward pressure can prevent the corrosion inhibitor flowing into the first corrosion channel 211 from the pipeline 04 from flowing back into the cavity 22. The corrosion inhibitor at the bottom of pipeline 04 and the corrosion inhibitor in the cavity 22 of the pre-filming pig 02 are atomized and sprayed out through nozzle 213. Some of them fall onto the surface of the pre-filming pig 02, forming a self-protective protective layer. Of course, when the pre-filming pig pushes forward to squeeze the corrosion inhibitor slug, the guide pig is also moving forward. However, the moving speed of the guide pig is smaller than that of the pre-filming pig and the driving pig, so that the corrosion inhibitor liquid level in the slug can rise when the pre-filming pig squeezes the corrosion inhibitor slug.

[0038] Initially, the corrosion inhibitor levels in the pre-filming pig 02 cavity 22 and the corrosion inhibitor levels in the pipeline 04 are roughly equal, indicating a state of equilibrium. As the pre-filming process proceeds, the corrosion inhibitor levels in the pipeline 04 gradually decrease, causing a siphon effect. Under the influence of gravity and air pressure, the corrosion inhibitor in the pre-filming pig 02 cavity 22 flows out from the first corrosion inhibitor channel 211 into the pipeline 04 until all the corrosion inhibitor in the cavity 22 has flowed out or has reached equilibrium with the corrosion inhibitor in the pipeline 04 again.

[0039] After pre-filming is completed, the anti-hydrogen embrittlement pig pushes out the impurities in pipeline 04. The anti-hydrogen embrittlement pig can then be removed through the pig launch and receiver system. This allows pre-filming to be performed without cutting off the gas supply to pipeline 04, and provides effective protection for the pig, thereby extending its service life.

[0040] like Figure 1 , 3 As shown in Figures 4 and 5, multiple first etchant channels 211 and two etchant channels 212 are provided, and they correspond one-to-one.

[0041] To enhance the pre-filming effect on pipeline 04, multiple first etchant channels 211 and second etchant channels 212 can be set according to actual conditions. Here, three are used as an example for detailed explanation. The left end of each of the three first etchant channels 211 is connected to the cavity 22, and the right end is connected downward through the head 21 to the outside. Utilizing the siphon effect, the corrosion inhibitor in the cavity 22 is discharged through these first etchant channels 211, ensuring that the corrosion inhibitor is sufficient during the long-distance pre-filming process of the anti-hydrogen embrittlement pig, thereby improving its endurance and pre-filming efficiency.

[0042] Each first etchant channel 211 is connected to a second etchant channel 212, and each second etchant channel 212 has a nozzle 213 connected to its right port. During pre-filming, the corrosion inhibitor flows from the first etchant channel 211 into its corresponding second etchant channel 212, and then is sprayed onto the top of the pipe wall through the nozzle 213. The multiple pipes 04 and multiple nozzles 213 are arranged to increase the spraying range and ensure that the corrosion inhibitor fully covers the inner wall of the pipe 04. On the other hand, it can increase the spray volume and ensure that enough corrosion inhibitor falls on the outer surface of the pre-filming pig 02, thereby enhancing the self-protection effect.

[0043] like Figure 1 As shown, a second support disc 25 is also fitted around the outer periphery of the pre-filming pig 02, and the second support disc 25 is fitted onto the other end of the cavity 22. Both the first support disc 24 and the second support disc 25 are provided with a cup 26.

[0044] The first support disc 24 and the second support disc 25 are respectively fitted onto the left and right ends of the pre-filming pig 02. The two support discs provide rigid support, ensuring that the pre-filming pig 02 maintains its original shape and does not tilt excessively during the pre-filming process. Each support disc is bolted with a rubber cup 26, which provides soft support to the pre-filming pig 02, improving the sealing and flowability between the pre-filming pig 02 and the inner wall of the pipeline 04. Furthermore, the rubber cup 26 is replaceable, thereby extending the service life of the pre-filming pig 02 and facilitating the pre-filming requirements of pipelines 04 with different diameters.

[0045] like Figure 6 As shown, the guide pig 01 is a foam pig 11. The drive pig 03 is also a foam pig 11.

[0046] Both the guide pig 01 and the drive pig 03 adopt the simple structure of the foam pig 11. This configuration can not only provide initial protection for the pre-filming pig 02, but also simplify the structure and save costs.

[0047] It should be noted that the terms "center", "upper", "lower", "front", "rear", "left", "right", "middle", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0048] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0049] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Various modifications and improvements made to the technical solutions of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.

Claims

1. A self-protective anti-hydrogen embrittlement pipeline cleaning device with a corrosion inhibitor for hydrogen-doped pipelines, characterized in that: The system includes a guide pig, a pre-filming pig, and a drive pig. The pre-filming pig is surrounded by a first support disc for support. The pre-filming pig includes a head, a hollow cavity, and a tail. The first support disc is fitted onto one end of the cavity. The head is disposed on the surface of the first support disc and connected to the cavity. The head contains a first etching channel and a second etching channel. One end of the first etching channel communicates with the cavity, and the other end communicates with the outside. One end of the second etching channel communicates with the first etching channel, and the other end communicates with the outside and has a nozzle at its port. The other end of the cavity is fixedly connected to the tail. The tail contains a third etching channel, one end of which communicates with the cavity, and the other end communicates with the outside.

2. The self-protective anti-hydrogen embrittlement pipeline cleaning device with corrosion inhibitor for hydrogen-doped pipelines according to claim 1, characterized in that: The first and second etchant channels are each provided in multiple quantities and correspond one-to-one.

3. The self-protective anti-hydrogen embrittlement pipeline cleaning device with corrosion inhibitor for hydrogen-doped pipelines according to claim 2, characterized in that: The pre-filming pig is also fitted with a second support disc on its outer periphery, which is fitted at the other end of the cavity.

4. A self-protective anti-hydrogen embrittlement pipeline cleaning device with corrosion inhibitor for hydrogen-doped pipelines according to claim 3, characterized in that: Both the first and second support discs are provided with leather cups.

5. A self-protective anti-hydrogen embrittlement pipeline cleaning device with corrosion inhibitor for hydrogen-doped pipelines according to claim 4, characterized in that: The guiding pig is a foam pig.

6. A self-protective anti-hydrogen embrittlement pipeline cleaning device with corrosion inhibitor for hydrogen-doped pipelines according to claim 5, characterized in that: The driving pig is also a foam pig.

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