High-pressure fluid storage container with oxidation resistance / hydrogen embrittlement resistance through surface treatment

Abstract

To provide a high-pressure fluid storage container which is surface-treated to have oxidation resistance / hydrogen embrittlement resistance, thereby enhancing sealability and enabling long-term use.SOLUTION: A high-pressure fluid storage container comprises: a container body, which has a storage space for storing high-pressure fluid inside, and a plug coupling portion formed at least on one of the two end portions thereof; and an end plug which is coupled to the plug coupling portion, and has a fluid passage hole formed internally to allow the flow of fluid therethrough. A surface-treated embrittlement-resistant layer is formed in an area where at least the plug coupling portion and the end plug come into contact with each other, in order to prevent oxidation and hydrogen embrittlement.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a high-pressure fluid storage container, and more particularly, to a high-pressure fluid storage container having oxidation resistance / hydrogen embrittlement resistance by surface treatment.

Background Art

[0002] Conventionally, fossil fuels, which have been utilized as the main energy source, have come to be concerned about depletion over time, and due to environmental pollution problems, human interest is gradually shifting to other alternative energy sources.

[0003] Among such alternative energy sources, hydrogen fuel has attracted attention. Hydrogen is not only extremely abundant but also has no concerns about environmental pollution and has very high potential.

[0004] In particular, automobiles using hydrogen fuel are being studied as an alternative to automobiles using existing internal combustion engines, and currently, the results are emerging.

[0005] Therefore, various studies are actively being conducted on storage containers that can be installed in automobiles, charging stations, etc. and safely store high-pressure hydrogen gas.

[0006] Generally, for hydrogen storage containers, a method is widely applied in which a pipe with a hollow formed inside is prepared and pressurized while being rotated by a spinning process to form the overall shape.

[0007] However, such hydrogen storage containers have a problem in that since they are continuously exposed to a high-pressure hydrogen gas environment, a hydrogen embrittlement phenomenon occurs in which hydrogen penetrates into the steel material inside and deteriorates the physical properties.

[0008] This not only greatly reduces the airtightness of the hydrogen storage container but also acts as a cause for shortening the lifespan.

[0009] Therefore, a method for solving such problems is required.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0011] The present invention has been made to solve the above-described problems of the prior art, and an object thereof is to provide a high-pressure fluid storage container that is surface-treated to have oxidation resistance / hydrogen embrittlement resistance, has improved airtightness, and can be used for a long time.

[0012] The problems of the present invention are not limited to the technical problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

Means for Solving the Problems

[0013] The high-pressure fluid storage container with oxidation resistance / hydrogen embrittlement resistance by surface treatment according to the present invention for achieving the above object includes a container body in which storage holes for storing high-pressure fluid are formed therein, and a plug coupling portion is formed at at least one of both ends, and an end plug coupled to the plug coupling portion and having a fluid passage hole through which fluid flows formed therein. At least in a region where the plug coupling portion and the end plug contact each other, a embrittlement-resistant treatment layer surface-treated to prevent oxidation and hydrogen embrittlement is formed.

[0014] At this time, the embrittlement-resistant treatment layer may be formed on both the plug coupling portion and the end plug.

[0015] Further, the container body and the end plug may be formed of a steel material containing chromium (Cr).

[0016] Further, the embrittlement-resistant treatment layer may be formed by the following steps: (a) loading the plug joint portion and the end plug into the chamber; (b) injecting air into the chamber and performing primary heating on the plug joint portion and the end plug in an atmospheric environment; (c) discharging the air in the chamber; and (d) injecting hydrogen into the chamber and performing secondary heating on the plug joint portion and the end plug in a hydrogen atmosphere.

[0017] At this time, in step (b), the plug joint portion and the end plug may be heated to a temperature of 600°C to 900°C in an atmospheric environment.

[0018] Furthermore, in step (d), the partial pressure of water vapor may be controlled to 10 -8 ~10 -1 MPa and heated to a temperature of 1000°C to 1200°C in a hydrogen atmosphere.

[0019] On the other hand, the present invention may further include an airtight formation unit provided in a ring-shaped seal groove formed between the end face of the container body and the opposing face of the end plug that contacts the end face of the container body to seal the interior of the storage space.

[0020] Also, the airtight formation unit may include a seal jacket formed of an elastic material and configured to be fitted into the seal groove, with an insertion space having an opening on one side formed inside; and a compression spring formed of a metal material and inserted into the insertion space, which provides elastic pressing forces on both sides centered on the opening of the insertion space to bring the seal jacket into close contact with the end face of the container body and the opposing face of the end plug.

Advantages of the Invention

[0021] In order to solve the above problems, the high-pressure fluid storage container with oxidation resistance / hydrogen embrittlement resistance by surface treatment of the present invention has a embrittlement resistance treatment layer formed by surface treatment in at least the region where the plug joint portion of the container body and the end plug are in contact with each other. Therefore, there is an advantage that oxidation of the material and penetration of hydrogen molecules into the material can be prevented, and airtightness can be improved.

[0022] In addition, the high-pressure fluid storage container according to the present invention can prevent oxidation of the material and embrittlement by hydrogen, so there is an advantage that it can be used for a long period of time.

[0023] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 8

Figure 9

[0025] In this specification, when a certain component (or region, layer, part, etc.) is referred to as being "on", "connected (joined) to", or "coupled to" another component, this means that it may be directly disposed / connected (joined) / or coupled on the other component, or a third component may be disposed between them.

[0026] The same reference numerals denote the same components. Also, in the drawings, the thickness, ratio, and dimensions of the components are exaggerated for an effective explanation of the technical content.

[0027] "And / or" includes all one or more combinations that can define the related configurations.

[0028] Terms such as first, second, third, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are only used to distinguish one component from another. For example, without departing from the scope of the present invention, the first component can be named the second component, and similarly, the second component can be named the first component. Singular expressions include plural expressions unless the context clearly gives a different meaning.

[0029] Also, terms such as "below", "underneath", "above", "on", "over" are used to explain the relative relationship of the configurations shown in the drawings. These terms are relative concepts and are explained based on the directions shown in the drawings.

[0030] Unless otherwise defined, all terms (including technical and scientific terms) used in this specification shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Also, terms defined in commonly used dictionaries shall be interpreted to have a meaning consistent with the meaning in the context of the relevant art, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined in this specification.

[0031] Terms such as "comprising" or "having" are used to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and do not preclude the presence or possibility of addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0032] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0033] FIG. 1 is a view showing a high-pressure fluid storage container 10 having oxidation resistance / hydrogen embrittlement resistance by surface treatment according to the first embodiment of the present invention.

[0034] As shown in FIG. 1, the high-pressure fluid storage container 10 according to the first embodiment of the present invention includes a container body 20 and an end plug 30.

[0035] The container body 20 has a storage space formed therein for storing a high-pressure fluid, and may have various lengths and shapes depending on the place and application to which it is applied.

[0036] Also, in this embodiment, the high-pressure fluid filled in the storage space is assumed to be hydrogen, but the high-pressure fluid applicable to the high-pressure fluid storage container 10 according to the present invention is not limited to hydrogen only.

[0037] The end plug 30 may be coupled to at least one of both ends of the container body 20.

[0038] That is, the end plug 30 may be provided only at one end of the container body 20 according to the form of the container body 20, or may be provided at both ends of the container body 20.

[0039] For this purpose, a plug coupling portion 20a for coupling with the end plug 30 may be formed at either one of both ends of the container body 20.

[0040] Also, a fluid passage hole 31 through which fluid flows may be formed inside the end plug 30. The fluid passage hole 31 forms a gas flow path in a state of being docked to a filling facility or a gas extraction facility outside the high-pressure fluid storage container 10.

[0041] On the other hand, in the present embodiment, the container body 20 and the end plug 30 may be formed of a steel material containing chromium (Cr), but the materials of the container body 20 and the end plug 30 are not limited thereto.

[0042] FIG. 2 is a cross-sectional view of one end of the high-pressure fluid storage container 10 having oxidation resistance / hydrogen embrittlement resistance by surface treatment according to the first embodiment of the present invention.

[0043] As shown in FIG. 2, in the high-pressure fluid storage container 10 of the present embodiment, a embrittlement resistance treatment layer C that is surface-treated to prevent oxidation and hydrogen embrittlement may be formed in at least a region where the plug coupling portion 20a and the end plug 30 are in contact with each other.

[0044] Such an embrittlement resistance treatment layer C serves to prevent oxidation of the materials constituting the container body 20 and the end plug 30 and the penetration phenomenon of hydrogen molecules into the materials.

[0045] Thereby, the embrittlement resistance treatment layer C can improve the airtightness of the high-pressure fluid storage container 10 of the present embodiment and enable long-term use.

[0046] Alternatively, the embrittlement-resistant treatment layer C may be formed on only one of the plug coupling portion 20a of the container body 20 or the end plug 30, or may be formed on both the plug coupling portion 20a of the container body 20 and the end plug 30.

[0047] In this embodiment, the embrittlement-resistant treatment layer C is illustrated as being formed on both the plug coupling portion 20a and the end plug 30.

[0048] On the other hand, the method of forming such an embrittlement-resistant treatment layer C is as follows.

[0049] FIG. 3 is a diagram showing the overall process of forming the embrittlement-resistant treatment layer C of the high-pressure fluid storage container 10 having oxidation resistance / hydrogen embrittlement resistance by surface treatment according to the first embodiment of the present invention.

[0050] As shown in FIG. 3, the process of forming the embrittlement-resistant treatment layer C may include steps (a) to (d).

[0051] Step (a) is a step of loading the plug coupling portion 20a of the container body 20 and the end plug 30 into the chamber.

[0052] At this time, when the entire container body 20 is surface-treated, the entire container body 20 may be loaded into the chamber. However, when only the plug coupling portion 20a of the container body 20 is surface-treated, only the plug coupling portion 20a is exposed in the chamber, and a pretreatment may be performed to prevent the processing gas supplied in the subsequent steps from diffusing to other parts of the container body 20.

[0053] Step (b) is a step of injecting air into the chamber and performing primary heating on the plug coupling portion 20a and the end plug 30 in an atmospheric environment.

[0054] In this embodiment, step (b) can be performed by heating the plug coupling portion 20a and the end plug 30 to a temperature of 600°C to 900°C in an atmospheric environment to form an oxide film.

[0055] This is because when heating is performed at a temperature lower than 600°C, the oxide film formed on the surfaces of the plug joint portion 20a and the end plug 30 does not have a sufficient thickness.

[0056] Also, when heating is performed at a temperature exceeding 900°C, an excessive oxide film is generated in this step, making it difficult to generate a brittle fracture resistant film in step (d) described later.

[0057] Next, step (c) is a step of discharging the air inside the chamber.

[0058] This is for step (d) described later and is a step of completely exhausting the air contained inside the chamber to the outside.

[0059] Step (d) is a step of injecting hydrogen into the chamber and performing secondary heating on the plug joint portion 20a and the end plug 30 in a hydrogen atmosphere.

[0060] In the present embodiment, step (d) can be performed in such a manner that the water vapor partial pressure is controlled to be 10 -8 ~10 -1 MPa in a hydrogen atmosphere, and the plug joint portion 20a and the end plug 30 are heated to a temperature of 1000°C to 1200°C to form a brittle fracture resistant film.

[0061] This is because when heating is performed at a temperature lower than 1000°C, the brittle fracture resistant film formed on the surfaces of the plug joint portion 20a and the end plug 30 does not have a sufficient thickness.

[0062] Also, when heating is performed at a temperature exceeding 1200°C, the brittle fracture resistant film becomes thick in this step, so there is a possibility that the adhesiveness of the entire brittle fracture resistant treatment layer C decreases.

[0063] As described above, in the high-pressure fluid storage container 10 according to the present invention, since the embrittlement-resistant treatment layer C that has been surface-treated is formed in at least the region where the plug coupling portion 20a of the container body 20 and the end plug 30 are in contact with each other, it is possible to prevent oxidation of the material and the penetration of hydrogen molecules into the material, improve airtightness, and has the advantage of being able to be used for a long period of time.

[0064] On the other hand, the high-pressure fluid storage container 10 of the present embodiment may further include an airtight formation unit provided in a ring-shaped seal groove formed between the end face of the container body 20 and the opposing face of the end plug 30 that contacts the end face of the container body 20, for sealing the inside of the storage space.

[0065] FIG. 4 is a diagram showing the state of the airtight formation unit 100 provided between the container body 20 and the end plug 30 in the high-pressure fluid storage container according to the first embodiment of the present invention.

[0066] As shown in FIG. 4, an airtight formation unit 100 for sealing the storage space is provided between the container body 20 and the end plug 30.

[0067] Such an airtight formation unit 100 is provided in a ring-shaped seal groove 32 formed between the end face of the container body 20 and the opposing face of the end plug 30 that contacts the end face of the container body 20, and serves to seal the inside of the storage space.

[0068] Further, the airtight formation unit 100 may specifically include a seal jacket 110 and a compression spring 120. Details of such each detailed configuration will be described later.

[0069] Furthermore, in the present embodiment, the seal groove 32 has a shape recessed on the side of the end plug 30, but this is merely an example, and the seal groove 32 may have a shape recessed on the side of the container body 20, or may have a shape recessed on both sides of the end plug 30 and the container body 20, needless to say.

[0070] FIG. 5 is a diagram showing the structure of the airtight formation unit 100 applied to the high-pressure fluid storage container 10 according to the first embodiment of the present invention.

[0071] As shown in FIG. 5, the seal jacket 110 is formed of an elastic material and is formed to be fitted into the seal groove 32, and has a shape in which an insertion space 111 with one side open is formed inside.

[0072] At this time, the seal jacket 110 can be disposed in the seal groove 32 such that the opening of the insertion space 111 faces the storage space on the high-pressure fluid leakage path.

[0073] Also, in the present embodiment, the seal jacket 110 may include a pair of close contact seal portions 113 and a connecting portion 112.

[0074] A pair of close contact seal portions 113 are provided so as to respectively contact the end face of the container body 20 or the opposing face of the end plug 30.

[0075] The connecting portion 112 connects one side of such a pair of close contact seal portions 113 to each other, and forms the insertion space 111 together with the pair of close contact seal portions 113.

[0076] That is, the seal jacket 110 has an insertion space 111 formed inside, and the insertion space 111 has a shape in which an opening is formed in a partial region.

[0077] More specifically, in the present embodiment, a lip 113a protruding in a shape curved outward may be formed on the outer surface of the connecting portion 112.

[0078] Such a lip 113 can be elastically deformed in a state of contacting the end face of the container body 20 or the opposing face of the end plug 30 to enhance airtightness.

[0079] Further, in the present embodiment, the connecting portion 112 may be formed with a detachment preventing projection 113b that extends toward the other connecting portion 112 on the opposite side and shields a part of the opening of the insertion space 11.

[0080] Such a detachment preventing projection 113b can prevent the compression spring 120 inserted into the insertion space 111 from coming off through the opening.

[0081] The compression spring 120 is formed of a metal material and inserted into the insertion space 111, and applies elastic pressure to both sides centered on the opening of the insertion space 111. Thereby, the compression spring 120 can play a role of bringing the seal jacket 110 into close contact with the end face of the container body 20 and the opposing face of the end plug 30.

[0082] Further, in the present embodiment, the compression spring 120 has a shape including an elastic imparting portion 121 and a pair of pressing portions 122.

[0083] Among these, the elastic imparting portion 121 is curved and serves to generate an elastic force.

[0084] Further, the pressing portion 122 extends from both sides of such an elastic imparting portion 121 by a predetermined length, and in a state of being inserted into the insertion space 111, serves to bring the pair of close contact seal portions 113 into close contact with the end face of the container body 20 or the opposing face of the end plug 30, respectively.

[0085] That is, in the present embodiment, the compression spring 120 is characterized in that it is curved at a predetermined location to generate an elastic force and has a cross section formed in an open curve shape.

[0086] Thereby, the present invention can provide a sealing force superior to that of conventional sealing means such as an O-ring.

[0087] Hereinafter, other embodiments of the present invention will be described. At this time, in each of the embodiments described below, redundant descriptions of the same components as those in the aforementioned first embodiment will be omitted. Further, for components not shown in the drawings in the following embodiments, the same reference numerals as those in the first embodiment will be given.

[0088] FIG. 6 is a view showing the state of the seal jacket 110 in the high-pressure fluid storage container 10 according to the second embodiment of the present invention.

[0089] In the second embodiment of the present invention shown in FIG. 6, the seal jacket 110 includes a connecting portion 112 and an adhering seal portion 113, and is formed to have substantially the same overall shape as that in the aforementioned first embodiment.

[0090] However, the seal jacket 110 of the present embodiment is characterized by further including a gap sealing portion 114 formed on one side of the connecting portion 112.

[0091] The gap sealing portion 114 is formed in a volume-expanded shape on one side of the connecting portion 112 so as to be able to fill a gap G (see FIG. 8) formed at the connecting portion between the container body 20 and the end plug 30, and can prevent the leakage phenomenon of the high-pressure fluid through the gap G.

[0092] In the present embodiment, the gap sealing portion 114 is exemplified as having a cross-sectional arc shape, but the shape of the gap sealing portion 114 can of course be changed without limitation.

[0093] FIG. 7 is a view showing the state of the seal jacket 110 in the high-pressure fluid storage container 10 according to the third embodiment of the present invention.

[0094] Also in the third embodiment of the present invention shown in FIG. 7, the seal jacket 110 includes a connecting portion 112 and an adhering seal portion 113, and is formed to have substantially the same overall shape as that in the aforementioned first embodiment.

[0095] However, the seal jacket 110 of the present embodiment is characterized in that it further includes an auxiliary concave groove 115 that is recessed from the inside of the insertion space 111 toward the connecting portion 112.

[0096] This auxiliary concave groove 115 serves to allow for easier expansion when the pair of close contact seal portions 113 are elastically deformed outward by the compression spring 120.

[0097] Also, in the present embodiment, the inner surface of the auxiliary concave groove 115 is entirely formed as a curved surface so as not to be easily damaged, but the shape of the auxiliary concave groove 115 can also be deformed in various ways.

[0098] FIG. 8 is a diagram showing the inside of the seal groove 32 and the state of the seal jacket 110 in the high-pressure fluid storage container 10 according to the fourth embodiment of the present invention.

[0099] Also in the fourth embodiment of the present invention shown in FIG. 8, the seal jacket 110 includes a connecting portion 112 and a close contact seal portion 113, and is formed to have substantially the same overall shape as the above-described embodiments.

[0100] However, in the present embodiment, a fluid blocking protrusion 21 that protrudes a predetermined length toward the internal space of the seal groove 32 is formed on the container body 20.

[0101] Also, in the present embodiment, the seal jacket 110 has a shape in which a protrusion insertion groove 116 into which the fluid blocking protrusion 21 can be inserted is formed, being recessed in a shape corresponding to the fluid blocking protrusion 21 with reference to the state in which the seal jacket 110 is inserted into the seal groove 32.

[0102] Thereby, in the state where the seal jacket 110 is inserted into the seal groove 32 in the present embodiment, the fluid blocking protrusion 21 is inserted into the protrusion insertion groove 116 of the seal jacket 110, so that the flow of high-pressure fluid into the gap G between the container body 20 and the end plug 30 inside the accommodation space of the high-pressure fluid storage container 10 can be physically blocked.

[0103] FIG. 9 is a view showing the inside of the seal groove 32 in the high-pressure fluid storage container 10 according to the fifth embodiment of the present invention.

[0104] In the fifth embodiment of the present invention shown in FIG. 9, a plurality of close-contact protrusions 22 and 33 protruding toward the internal space of the seal groove 32 are sequentially arranged on each of the end face of the container body 20 and the opposing face of the end plug 30.

[0105] These close-contact protrusions 22 and 33 can strongly press the outer surface of the close-contact seal portion 113 in a state where the seal jacket 110 is inserted into the seal groove 32, thereby maximizing the sealing effect.

[0106] Although the preferred embodiments according to the present invention have been described above, it is obvious to those having ordinary knowledge in the art that the present invention can be embodied in other specific forms without departing from the spirit and scope thereof. Therefore, the above-described embodiments are regarded as illustrative rather than restrictive, and thus the present invention is not limited to the above description and may be modified within the scope of the appended claims and their equivalents.

Description of Reference Numerals

[0107] 10 High-pressure fluid storage container 20 Container body 20a Plug coupling portion 21 Fluid blocking protrusion 22, 33 Close-contact protrusions 30 End plug 31 Fluid passage hole 32 Seal groove 100 Airtight formation unit 110 Seal jacket 111 Insertion space 112 Connection portion 113 Close-contact seal portion 113a Lip 113b Separation prevention protrusion 114 Gap sealing part 115 Auxiliary concave groove 116 Protrusion insertion groove 120 Pressing spring 121 Elasticity imparting part 122 Pressing part C Brittleness resistance treatment layer

Claims

1. A container body having a storage space for storing a high-pressure fluid formed therein, and a plug coupling portion formed at at least one of both ends; An end plug coupled to the plug coupling portion and having a fluid passage hole formed therein through which fluid flows; comprising: At least in a region where the plug coupling portion and the end plug are in contact with each other, a brittle fracture resistant treatment layer surface-treated to prevent oxidation and hydrogen embrittlement is formed. A high-pressure fluid storage container characterized by the above.

2. The brittle fracture resistant treatment layer is formed on both the plug coupling portion and the end plug. The high-pressure fluid storage container according to Claim 1.

3. The container body and the end plug are formed of a steel material containing chromium (Cr). The high-pressure fluid storage container according to Claim 2.

4. The brittle fracture resistant treatment layer is formed by the steps of: (a) loading the plug coupling portion and the end plug into a chamber; (b) injecting air into the chamber and performing primary heating on the plug coupling portion and the end plug in an atmospheric environment; (c) discharging the air in the chamber; (d) injecting hydrogen into the chamber and performing secondary heating on the plug coupling portion and the end plug in a hydrogen atmosphere. The high-pressure fluid storage container according to Claim 3.

5. In step (b), the plug coupling portion and the end plug are heated to a temperature of 600°C to 900°C in an atmospheric environment. The high-pressure fluid storage container according to Claim 4.

6. In step (d), Under a hydrogen atmosphere, control the water vapor partial pressure to 10 －８ ~10 －１ MPa and heat to a temperature of 1000 °C to 1200 °C The high-pressure fluid storage container according to Claim 4.

7. Further comprising an airtight formation unit provided in a ring-shaped seal groove formed between an end face of the container body and a facing surface of the end plug that contacts the end face of the container body, for sealing the inside of the storage space. The high-pressure fluid storage container according to Claim 1.

8. The airtight formation unit includes: A seal jacket formed of an elastic material and configured to be fitted into the seal groove, having an insertion space with one side open inside; A compression spring formed of a metal material and inserted into the insertion space, providing elastic pressing force on both sides around the opening of the insertion space to bring the seal jacket into close contact with the end face of the container body and the facing surface of the end plug. The high-pressure fluid storage container according to Claim 7.

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