Connecting structure for hydrogen storage well shaft casing and coating method

Abstract

The invention belongs to the technical field of hydrogen energy development equipment, and particularly relates to a connecting structure for a hydrogen storage well shaft casing and a coating method. The connecting structure for the hydrogen storage well shaft casing pipe comprises a first connecting end and a second connecting end, the first connecting end comprises a first main body, a first main sealing face and a first auxiliary sealing face, and the second connecting end comprises a second main body, a second main sealing face and a second auxiliary sealing face. After the first connecting end and the second connecting end are connected, the contact interference magnitude of the first main sealing face and the second main sealing face is larger than the contact interference magnitude of the first auxiliary sealing face and the second auxiliary sealing face. The connecting structure for the hydrogen storage well shaft sleeve has the advantages of being good in sealing effect, low in screwing torque and the like, and has good application prospects in the technical field.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen energy development equipment, and in particular relates to a connection structure for a wellbore casing of a hydrogen storage well and a coating coating method. Background Art

[0002] Hydrogen has received widespread attention as a clean energy source. At present, the most mature hydrogen storage technology is high-pressure gaseous hydrogen storage. Among them, underground high-pressure gaseous hydrogen storage wells are the dominant technology for high-pressure gaseous hydrogen storage due to their advantages such as small footprint, large capacity and high safety.

[0003] However, due to the small size of hydrogen molecules, they are very easy to leak, and the sealing problem of the casing connection of the hydrogen storage well is the key to the safe and efficient operation of the hydrogen storage well. The connection structure of the casing used in the existing technology for hydrogen storage wells has the problem of low sealing reliability for small molecular gases such as hydrogen that are easy to escape, which has a certain degree of restriction on the development of high-pressure gaseous hydrogen storage technology. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a connection structure and a coating coating method for a wellbore casing of a hydrogen storage well.

[0005] According to a first aspect of the present invention, a connection structure for a wellbore casing of a hydrogen storage well is provided.

[0006] The connection structure for the casing of the hydrogen storage well comprises:

[0007] A first connecting end includes a first body, a first main sealing surface and a first auxiliary sealing surface disposed outside a lower end of the first body; and

[0008] The second connecting end includes a second body, a second main sealing surface and a second auxiliary sealing surface arranged on the inner side of the lower end of the second body,

[0009] Among them, the connection structure for the hydrogen storage well casing is constructed so that when the first connecting end is connected to the second connecting end, the contact interference between the first main sealing surface and the second main sealing surface is greater than the contact interference between the first auxiliary sealing surface and the second auxiliary sealing surface.

[0010] As an extension of the above technical solution, the present invention also provides the following embodiments:

[0011] A first transition section is provided on the outer surface of the first body at a position between the first main sealing surface and the first auxiliary sealing surface, and a second transition section corresponding to the first transition section is provided on the inner surface of the second body at a position between the second main sealing surface and the second auxiliary sealing surface.

[0012] An angle α formed by the first transition section and the inner surface of the first main body is greater than an angle β formed by the second transition section and the innermost surface of the second main body.

[0013] A first thread is arranged on the outer surface of the first body, a second thread is arranged on the inner surface of the second body, and the first connection end and the second connection end are threadedly connected by combining the first thread and the second thread.

[0014] The thread crest of the first thread is configured to be parallel to the axis of the first connecting end.

[0015] The thread crest of the second thread is configured to be parallel to the axis of the second connecting end.

[0016] A solid lubricating coating is provided on the outer surface of the first connecting end.

[0017] A solid lubricating coating is provided on the inner surface of the second connecting end.

[0018] The fixed lubricating coating is formed by coating with a solid lubricating material.

[0019] The solid lubricating material is nano-scale molybdenum disulfide.

[0020] It includes a third connection end, which has the same structure as the second connection end, is fixedly arranged below the second connection end and is in a mirror-symmetrical state with the second connection end.

[0021] According to a second aspect of the present invention, a coating application method is provided.

[0022] The coating application method comprises the following steps:

[0023] 1) performing a phosphating process pretreatment on the first connecting end and the second connecting end of the connecting structure for the wellbore casing of the hydrogen storage well as described above;

[0024] 2) spraying a solid lubricating material onto the first connecting end and the second connecting end;

[0025] 3) Performing a solid lubricating material curing treatment on the first connection end and the second connection end after spraying.

[0026] The advantages of the present invention compared to the prior art are:

[0027] (1) The dual-stage structure combining the main sealing surface and the auxiliary sealing surface can provide better sealing effect and effectively prevent hydrogen leakage;

[0028] (2) The main sealing surface and the auxiliary sealing surface adopt a differentiated interference fit design, which not only improves the sealing performance of the sealing structure, but also controls the screwing torque within a reasonable range, reducing the difficulty of connection;

[0029] (3) By differentially designing the angle values ​​of α and β, the length of the contact slip zone in the transition section is effectively shortened, the contact friction is reduced, and thus the make-up torque is reduced;

[0030] (4) By setting the thread tops of the first thread and the second thread to be parallel to the axial direction, the width and contact area of ​​the contact friction surface of the thread are reduced during the connection process, thereby reducing the contact friction and facilitating the make-up operation for the staff;

[0031] (5) By providing a solid lubricating coating on the first connecting end and the second connecting end, the smoothness during the screwing process is ensured and the occurrence of sticking is reduced. At the same time, the use of grease products is avoided, thereby achieving the purpose of preventing the hydrogen stored in the sleeve from being contaminated. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the longitudinal cross-section structure of the connection structure for the casing of a hydrogen storage well according to the present invention;

[0033] Figure 2 for Figure 1 A schematic diagram of the enlarged structure of the portion in the middle rectangular dotted frame;

[0034] Figure 3 for Figure 2 Schematic diagram of the separation of the two parts of the structure;

[0035] Figure 4 Schematic diagram for comparing different thread tooth structures.

[0036] All drawings in this application are schematic diagrams for illustrating structures and principles, and are not necessarily drawn according to actual sizes and proportions.

[0037] The specific meanings of the reference numerals in the figures are as follows:

[0038] 1. First connection end; 11. First body; 12. First main sealing surface; 13. First auxiliary sealing surface; 14. First thread; 15. First transition section; 2. Second connection end; 21. Second body; 22. Second main sealing surface; 23. Second auxiliary sealing surface; 24. Second thread; 25. Second transition section; 3. Third connection end; 100. Connection structure for casing of hydrogen storage well. DETAILED DESCRIPTION

[0039] The embodiments of the present invention will be described in more detail below with reference to the accompanying drawings.

[0040] According to a first aspect of the present invention, a connection structure 100 for a casing of a hydrogen storage well (hereinafter referred to as “connection structure 100 ”) is provided.

[0041] Figure 1 It is a structural schematic diagram of the longitudinal section of the connection structure 100 according to the present invention. As shown in the figure, the connection structure 100 includes a first connection end 1 and a second connection end 2 constructed in a cylindrical shape. The first connection end 1 includes a first body 11, and a first main sealing surface 12 and a first auxiliary sealing surface 13 arranged on the outer side of the lower end of the first body 11 in order from top to bottom. The second connection end 2 includes a second body 21, and a second main sealing surface 22 and a second auxiliary sealing surface 23 arranged on the inner side of the lower end of the second body 21 in order from top to bottom. The connection structure 100 is also constructed so that when the first connection end 1 and the second connection end 2 are connected, the first main sealing surface 12 and the second main sealing surface 22 can achieve an interference fit, and the first auxiliary sealing surface 13 and the second auxiliary sealing surface 23 can also achieve an interference fit. In addition, the contact interference amount of the first main sealing surface 12 and the second main sealing surface 22 is greater than the contact interference amount of the first auxiliary sealing surface 13 and the second auxiliary sealing surface 23.

[0042] During the specific operation, the worker connects the first connection end 1 and the second connection end 2. When the connection operation is carried out to a certain extent, the first main sealing surface 12 and the second main sealing surface 22 first begin to contact, and as the connection continues, while the first main sealing surface 12 and the second main sealing surface 22 maintain contact, the first auxiliary sealing surface 13 and the second auxiliary sealing surface 23 also begin to contact, and this trend continues until the connection is completed.

[0043] Through this design, the connection structure 100 includes a double sealing surface with primary and secondary differentiated characteristics. Thus, on the one hand, the connection structure 100 has a double sealing guarantee, and on the other hand, the design of the sealing surface with primary and secondary differentiated characteristics can avoid the occurrence of a situation where the sealing performance is reduced due to over-positioning of the main sealing surface. The above technical features enable the connection structure 100 to have excellent sealing performance and can effectively prevent hydrogen leakage.

[0044] In a preferred embodiment of the present invention, the interference fit between the first main sealing surface 12 and the second main sealing surface 22 is greater than the interference fit between the first auxiliary sealing surface 13 and the second auxiliary sealing surface 23 in the range of 0.1 to 0.6 mm.

[0045] like Figure 1 and Figure 2As shown, in one embodiment of the present invention, a first transition section 15 is provided at a position between the first main sealing surface 12 and the first auxiliary sealing surface 13 on the outer surface of the first body 11. A second transition section 25 corresponding to the first transition section 15 is provided at a position between the second main sealing surface 22 and the second auxiliary sealing surface 23 on the inner surface of the second body 21. In this case, during the specific operation, when the connection between the first connection end 1 and the second connection end 2 is carried out to a certain extent, the first transition section 15 and the second transition section 25 first come into contact. Afterwards, as the connection continues, the first main sealing surface 12 and the second main sealing surface 22 come into contact, at which time, the contact interference between the first transition section 15 and the second transition section 25 reaches the maximum. Afterwards, as the connection continues, the first auxiliary sealing surface 13 and the second auxiliary sealing surface 23 come into contact, at which time, the first main sealing surface 12 and the second main sealing surface 22 still maintain contact, but the first transition section 15 and the second transition section 25 begin to separate, and this trend continues until the connection between the first connection end 1 and the second connection end 2 is terminated. This design can effectively reduce the difficulty of connecting the first connection end 1 and the second connection end 2, and can also effectively reduce the pressure of the closed space formed between the first transition section 15 and the second transition section 25 after the connection is completed, which is conducive to the staff to smoothly complete the connection operation.

[0046] Furthermore, if Figure 3 As shown, in one embodiment of the present invention, the angle α formed by the first transition section 15 and the inner surface of the first body 11 is greater than the angle β formed by the second transition section 25 and the innermost surface of the second body 21. Through this design, the length of the contact sliding zone between the first transition section 15 and the second transition section 25 can be reduced, thereby reducing the contact friction and the make-up torque.

[0047] Preferably, the angle difference between α and β is in the range of 2-5°.

[0048] like Figure 1As shown, in one embodiment of the present invention, a first thread 14 is provided on the outer surface of the first body 11 at a position above the first main sealing surface 12 and the first auxiliary sealing surface 13, and a second thread 24 is provided on the inner surface of the second body 21 at a position above the second main sealing surface 22 and the second auxiliary sealing surface 23. The first connection end 1 and the second connection end 2 are threadedly connected by combining the first thread 14 and the second thread 24. Through this design, the connection between the first connection end 1 and the second connection end 2 can be conveniently, quickly and stably achieved. In addition, the threaded connection also has the characteristic of being able to gradually apply the tightening force, which can play a positive role in giving full play to the sealing effect between the first main sealing surface 12, the first auxiliary sealing surface 13, the second main sealing surface 22 and the second auxiliary sealing surface 23, and reducing the possibility of damage between the first connection end 1 and the second connection end 2 due to high-intensity collision.

[0049] In one embodiment of the present invention, the thread top of the first thread 14 is configured to be parallel to the axis of the first connection end 1. With this design, when the thread parameters such as pitch, pitch diameter, and tooth height are the same, the contact area of ​​the thread top can be reduced compared to the prior art, thereby helping to reduce the contact friction during the make-up and facilitating the connection operation of the staff. Specifically, Figure 4 As shown, when the first thread 14 is constructed in the manner of this embodiment, the thread tooth top BD is parallel to the axial direction of the first connection end 1, and the thread tooth top BD is also the contact friction surface. When the first thread 14 is constructed in the manner of the prior art, its thread tooth top AC is parallel to the conical tooth of the thread bottom surface FG, and the contact friction surface is AC. By translating AC to BE, it can be seen that ∠BED (δ) is smaller than ∠BDE (γ), so the sides corresponding to the respective angles also have the same size relationship, that is, AC is greater than BE, that is, AC is greater than BD, and BD is a narrower contact friction surface than AC. Therefore, by constructing the first thread 14 as the structure in this embodiment, the technical effect of reducing contact friction can be achieved.

[0050] In one embodiment of the present invention, the thread top of the second thread 24 is configured to be parallel to the axis of the second connection end 2. With this design, when the thread parameters such as pitch, pitch diameter, and tooth height are the same, the contact area of ​​the thread top can be reduced, thereby facilitating the contact friction during the make-up and facilitating the connection operation of the staff. The specific reasons are the same as those in the previous embodiment and will not be repeated here.

[0051] In one embodiment of the present invention, a solid lubricating coating is provided on part or all of the outer surface of the first connection end 1. The use of a solid lubricating coating has the following advantages: first, the solid lubricating coating has good film-forming ability, can form a firm physical adsorption film with the thread surface, sealing surface and other parts, has the function of protecting the surface, and prevents the bonding damage of the contact surface that slides relatively during the buckle and other connection operations; second, the solid lubricating coating has a low shear strength, a small friction coefficient of the friction pair, low power loss, small temperature rise, and its shear strength is less affected by temperature changes; third, it has good physical thermal stability, chemical thermal stability and aging stability, does not produce corrosion and other harmful effects, and is conducive to long-term use; fourth, the solid lubricating coating has a high load-bearing capacity and can withstand multiple connection operations without failure; fifth, it avoids the use of grease lubricants, thereby avoiding the pollution of the hydrogen stored in the casing.

[0052] Preferably, according to different application scenarios, in order to save solid lubricating coatings while making the use of solid lubricating coatings more targeted and to give full play to the lubricating effect of solid lubricating coatings, solid lubricating coatings are provided on the first main sealing surface 12 and / or the first auxiliary sealing surface 13 and / or the first thread 14 and / or the first transition section 15 on the outer surface of the first connecting end 1.

[0053] In one embodiment of the present invention, the thickness of the solid lubricating coating disposed on the outer surface of the first connecting end 1 is evenly distributed.

[0054] Preferably, the thickness of the solid lubricating coating provided on the first main sealing surface 12 and / or the first auxiliary sealing surface 13 and / or the first thread 14 and / or the first transition section 15 on the outer surface of the first connecting end 1 is evenly distributed.

[0055] In one embodiment of the present invention, the thickness of the solid lubricating coating is in the range of 10 to 50 μm.

[0056] Preferably, the thickness of the solid lubricating coating provided on the first main sealing surface 12 and / or the first auxiliary sealing surface 13 and / or the first thread 14 and / or the first transition section 15 on the outer surface of the first connecting end 1 is in the range of 10 to 50 μm.

[0057] In one embodiment of the present invention, a solid lubricating coating is provided on part or all of the inner surface of the second connecting end 2. This embodiment is also an application of the solid lubricating coating, which can produce the technical effects that the solid lubricating coating can produce as described above, and will not be repeated here.

[0058] Preferably, according to different application scenarios, in order to save solid lubricating coatings while making the use of solid lubricating coatings more targeted and to give full play to the lubricating effect of solid lubricating coatings, solid lubricating coatings are provided on the second main sealing surface 22 and / or the second auxiliary sealing surface 23 and / or the second thread 24 and / or the second transition section 25 on the inner surface of the second connecting end 2.

[0059] In one embodiment of the present invention, the thickness of the solid lubricating coating disposed on the inner surface of the second connecting end 2 is evenly distributed.

[0060] Preferably, the thickness of the solid lubricating coating provided on the second primary sealing surface 22 and / or the second auxiliary sealing surface 23 and / or the second thread 24 and / or the second transition section 25 on the inner surface of the second connecting end 2 is evenly distributed.

[0061] In one embodiment of the present invention, the thickness of the solid lubricating coating is in the range of 10 to 50 μm.

[0062] Preferably, the thickness of the solid lubricating coating provided on the second primary sealing surface 22 and / or the second auxiliary sealing surface 23 and / or the second thread 24 and / or the second transition section 25 on the outer surface of the second connecting end 2 is in the range of 10 to 50 μm.

[0063] In one embodiment of the present invention, the solid lubricating coating is coated with a solid lubricating material. The solid lubricating material contains a lubricating component, so the surface of the solid lubricating coating is smooth, which can provide good protection for the joint during storage and use, and is smoother when screwing, which can greatly reduce the occurrence of sticking.

[0064] Preferably, the solid lubricating material is nano-scale molybdenum disulfide. The use of nano-scale molybdenum disulfide has many advantages: first, nano-scale molybdenum disulfide particles can be strongly adsorbed on the metal surface. Due to their small size, they can fill the micro-pits on the metal surface and form a "repairing layer" on the metal surface that is flatter and smoother than the original surface, thereby reducing friction and wear; second, molybdenum disulfide itself is an excellent solid lubricant, and its molecular structure is a hexagonal layered structure that can withstand higher contact pressure and higher friction speed. As the particle size of molybdenum disulfide becomes smaller, its adhesion and coverage on the surface of the friction material are significantly improved, and its anti-wear and friction-reducing properties are also doubled; finally, the friction under higher contact pressure causes the molybdenum disulfide particles to stay in the metal contact area for a shorter time. The external load does not have enough time to flatten the molybdenum disulfide particles, and they are not adsorbed by the metal surface. The nano-scale molybdenum disulfide particles have left the contact area. At this time, the nano-particles can play a role similar to a miniature "ball bearing" and can form a rolling bearing effect, thereby effectively reducing friction and wear.

[0065] like Figure 1 As shown, in one embodiment of the present invention, the connection structure 100 includes a third connection end 3. The third connection end 3 is constructed in the same structure as the second connection end 2, is fixedly arranged below the second connection end 2 and is in a mirror-symmetrical state with the second connection end 2. Through this design, the second connection end 2 and the third connection end 3 are combined into a connection end portion, both ends of which can be connected to the casing having the structure of the first connection end 1. Since multiple casings generally need to be connected underground, this design can more conveniently meet the actual connection requirements, and since the second connection end 2 and the third connection end 3 are fixedly connected, the connection end portion has good sealing performance.

[0066] Preferably, the fixed arrangement between the second connection end 2 and the third connection end 3 means that the two are integrally formed during manufacture. This design is conducive to further improving the sealing performance of the connection end and reducing the probability of hydrogen leakage.

[0067] Further preferably, the second connection end 2 and the third connection end 3 are respectively arranged at the upper and lower ends of a sleeve.

[0068] In summary, the connection structure 100 according to the present invention can effectively prevent leakage of hydrogen in the hydrogen storage well, improve the operational stability and safety of the hydrogen storage well, and has the advantages of simple structure, easy installation and high reliability.

[0069] According to a second aspect of the present invention, a coating application method is provided.

[0070] The coating application method comprises the following steps:

[0071] 1) performing a phosphating process pretreatment on the first connection end 1 and the second connection end 2 in the connection structure 100 as described above;

[0072] 2) Perform coating in a clean and dry environment, spray the solid lubricant on the first connection end 1 and the second connection end 2 by atomization, and the solid lubricant needs to completely cover the threaded portion and / or the sealing surface and / or the transition portion;

[0073] 3) The first connection end 1 and the second connection end 2 that have been sprayed are subjected to a solid lubricant curing treatment.

[0074] Step 1) can improve the adhesion of the solid lubricant, and step 3) can optimize the adhesion of the solid lubricant.

[0075] In one embodiment of the present invention, with respect to an embodiment of a connection structure 100 including a third connection end 3, improvements are made to step 1), step 2) and step 3), and the specific improvements are as follows: step 1) also includes pre-treatment of the third connection end 3 with a phosphating process, step 2) also includes atomizing spraying of a solid lubricant material on the third connection end 3, and step 3) also includes curing treatment of the solid lubricant material on the sprayed third connection end 3.

[0076] In addition, the coating coating method according to the present invention can also achieve other technical effects that can be achieved by the solid lubricating coating as described above, which will not be repeated here.

[0077] In the present application, the connection structure 100 may be a structure disposed on the sleeve, or may be a separate connection component.

[0078] In this application, "interference contact" refers to the radial distance between a surface of a component and the contact surface of another component in an assembly. Generally, when the interference contact is a positive value, it means that there is interference contact between the components, and when the interference contact is a negative value, it means that there is a gap between the components. The larger the interference contact, the larger the radial distance of the interference contact between the two components.

[0079] In this application, the specific meanings of the terms "upper", "lower", "inner", "outer", "middle", "side" and the like when indicating directions are as follows: Figure 1 The drawing state of the connection structure 100 is for reference.

[0080] Finally, it should be noted that although the present invention has been described in detail with reference to the preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A connection structure for a hydrogen storage well casing, comprising: A first connecting end (1) comprises a first main body (11), a first main sealing surface (12) and a first auxiliary sealing surface (13) arranged on the outer side of the lower end of the first main body (11); and The second connecting end (2) comprises a second main body (21), a second main sealing surface (22) and a second auxiliary sealing surface (23) arranged on the inner side of the lower end of the second main body (21), The connection structure for the casing of the hydrogen storage well is constructed so that when the first connection end (1) and the second connection end (2) are connected, the contact interference between the first main sealing surface (12) and the second main sealing surface (22) is greater than the contact interference between the first auxiliary sealing surface (13) and the second auxiliary sealing surface (23).

2. The connection structure for the casing of a hydrogen storage well according to claim 1, characterized in that: A first transition section (15) is provided on the outer surface of the first body (11) at a position between the first main sealing surface (12) and the first auxiliary sealing surface (13), and a second transition section (25) corresponding to the first transition section (15) is provided on the inner surface of the second body (21) at a position between the second main sealing surface (22) and the second auxiliary sealing surface (23).

3. The connection structure for the casing of a hydrogen storage well according to claim 2, characterized in that: An angle α formed by the first transition section (15) and the inner surface of the first main body (11) is greater than an angle β formed by the second transition section (25) and the innermost surface of the second main body (21).

4. The connection structure for the casing of a hydrogen storage well according to claim 3, characterized in that: A first thread (14) is provided on the outer surface of the first body (11), and a second thread (24) is provided on the inner surface of the second body (21); the first connecting end (1) and the second connecting end (2) are threadedly connected by combining the first thread (14) and the second thread (24).

5. The connection structure for the casing of a hydrogen storage well according to claim 4, characterized in that: The thread crest of the first thread (14) is configured to be parallel to the axis of the first connecting end (1).

6. The connection structure for the casing of a hydrogen storage well according to claim 5, characterized in that: The thread crest of the second thread (24) is configured to be parallel to the axis of the second connecting end (2).

7. The connection structure for the casing of a hydrogen storage well according to any one of claims 1 to 6, characterized in that: A solid lubricating coating is provided on the outer surface of the first connecting end (1).

8. The connection structure for the casing of a hydrogen storage well according to claim 7, characterized in that: A solid lubricating coating is provided on the inner surface of the second connecting end (2).

9. The connection structure for the casing of a hydrogen storage well according to claim 8, characterized in that: The fixed lubricating coating is formed by coating with a solid lubricating material.

10. The connection structure for the casing of a hydrogen storage well according to claim 9, characterized in that: The solid lubricating material is nano-scale molybdenum disulfide.

11. The connection structure for the casing of a hydrogen storage well according to any one of claims 1 to 6, characterized in that: It comprises a third connection end (3), the third connection end (3) having the same structure as the second connection end (2), being fixedly arranged below the second connection end (2) and being in a mirror-symmetrical state with the second connection end (2).

12. A coating application method comprising the following steps: 1) Pre-treating the first connecting end (1) and the second connecting end (2) of the connecting structure for the casing of a hydrogen storage well according to any one of claims 7 to 11 by a phosphating process; 2) spraying a solid lubricating material onto the first connecting end (1) and the second connecting end (2); 3) performing a solid lubricating material curing treatment on the first connection end (1) and the second connection end (2) that have been sprayed.

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