JP6688947B1 - Pressure vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure vessel which does not require a total annealing at a construction site. SOLUTION: In a pressure vessel in which an upper limit value of a base material thickness that does not require heat treatment after welding in a welded portion is defined by a law and an outer shell is formed by butt welding of a plurality of plate materials, a plurality of plate materials are The plate member 11, the second plate member 12, and the third plate member 13 are provided. The first plate member 11 has a nozzle mounting plate member 15A in which the nozzles 20 and 21 are integrally provided, and the second plate member 12 and the third plate member 13 are provided. Has a higher tensile strength than the first plate member 11, the plate thickness of the first plate member 11 is larger than the upper limit value, the plate thickness of the third plate member 13 is not more than the upper limit value, and the first plate member 11 is the second plate member. It is characterized in that it is attached to the third plate member 13 via 12. [Selection diagram] Fig. 3

Description

  The present invention relates to a pressure vessel in which high pressure gas is stored.

  In the High Pressure Gas Safety Act and the Gas Business Act, when manufacturing a pressure vessel such as a gas holder (gas tank) using a plate material that exceeds the base material thickness specified by law, in order to remove the internal stress generated in the welded part, It stipulates that the heat treatment after welding should be performed by an appropriate method. With a large pressure vessel where plate materials are assembled at the construction site, the entire pressure vessel cannot be put into the annealing furnace at the construction site. Therefore, it is necessary to anneal the entire pressure vessel at the construction site according to each law. However, in the annealing of the entire pressure vessel at the construction site, there are many points to be noted such as deformation of the pressure vessel due to heating, uniformization of temperature, control of heating / cooling rate, and the construction cost increases. Therefore, normally, the pressure vessel is manufactured using a plate material having a plate thickness that does not require annealing of the welded part (a plate thickness equal to or less than the base material thickness defined by law).

  A pressure vessel described in Patent Document 1 has been proposed as a pressure vessel that does not require total annealing. The outer shell of the pressure vessel is formed by welding a nozzle mounting plate member integrally provided with a nozzle and a plate member having no opening. The plate thickness of the plate material having no opening is equal to or less than the upper limit value of the base material thickness specified by law. In addition, the peripheral edge of the nozzle mounting plate material is tapered, and the plate thickness of the end surface of the nozzle mounting plate material is also set to the upper limit value or less. This eliminates the need for annealing the welded portion between the nozzle mounting plate and the plate having no opening.

Japanese Patent No. 5719759

  Other forms of pressure vessels that do not require total annealing at the construction site are being explored.

  The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a pressure vessel that does not require total annealing at a construction site.

In order to solve the above problems, the present invention proposes the following means.
The pressure vessel according to the present invention, the upper limit of the base material thickness that does not require heat treatment after welding in the welded portion is specified by law, in a pressure vessel in which the outer shell is formed by butt welding of a plurality of plate materials, the plurality of The plate member includes a first plate member, a second plate member, and a third plate member, the first plate member has a nozzle mounting plate member integrally provided with a nozzle, and the second plate member and the third plate member are The tensile strength is greater than that of the first plate member, the plate thickness of the first plate member is greater than the upper limit value, the plate thickness of the third plate member is less than or equal to the upper limit value, and the first plate member is the second plate member. It is characterized in that it is attached to the third plate member via the above.

For parts that require heat treatment after welding by law, heat treatment after welding is performed using an annealing furnace, while welding of plate materials that do not require heat treatment after welding is performed at the construction site. The pressure vessel can be manufactured without performing the entire annealing of the pressure vessel in the field. In addition, by using a plate material having a higher strength than the first plate material and a plate thickness not more than the legal upper limit value as the third plate material, the storage tank capacity of the pressure vessel can be increased.
Moreover, the strength of the nozzle can be secured by using the first plate member having a plate thickness larger than the legal upper limit value as the nozzle mounting plate member on which the nozzle is provided.
Furthermore, by using a plate material having a lower tensile strength than the second plate material and the third plate material as the first plate material, the first plate material can be manufactured at low cost.

  Further, in the pressure vessel according to the present invention, in the second plate member, a plate thickness at a first end surface facing the first plate member is equal to a plate thickness of the first plate member, Among them, the plate thickness at the second end face facing the third plate member is equal to the plate thickness of the third plate member, and the plate thickness of the second plate member gradually decreases toward the second end face. You may have a peripheral part.

Further, in the pressure vessel according to the present invention, the first plate member is formed of 610 N / mm ² class high-strength steel having a plate thickness of 50 mm, and the second plate member is a first end face facing the first plate member. The plate thickness is 50 mm, and the second end face facing the third plate member has a plate thickness of 38 mm at 780 N / mm. It is formed from ^second grade high-strength steel, and the third plate member has a plate thickness of 38 mm at 780 N / mm. ^It may be formed from ^second grade high strength steel.

  According to the present invention, it is possible to provide a pressure vessel that does not require total annealing at a construction site.

It is a front view of the gas holder which concerns on one Embodiment of this invention. It is a bottom view of the gas holder which concerns on one Embodiment of this invention. It is a longitudinal cross-sectional view of the bottom side of the gas holder according to an embodiment of the present invention. It is a top view of the gas holder which concerns on one Embodiment of this invention. It is an expanded sectional view showing a welding portion of the 2nd plate material and the 3rd plate material of a gas holder concerning one embodiment of the present invention.

  Hereinafter, a gas holder (pressure vessel) 1 according to an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, a plurality of columns 31 are arranged on the outer peripheral portion of the gas holder 1 so as to surround the gas holder 1. The gas holder 1 is fixed on the gland 33 via a plurality of columns 31. A tie rod brace 32 is attached in an X shape between the columns 31. The weight of the gas holder 1 is supported by the support column 31, and the tie rod brace 32 resists the horizontal force acting on the gas holder 1 during an earthquake.

The gas holder 1 is a spherical shell having a diameter of about 14 m. The storage tank capacity of the gas holder 1 is about 1500 m ³ . The outer shell of the gas holder 1 is formed by butt-welding the end surfaces of a plurality of curved plate materials (having a certain curvature). In the present embodiment, the plurality of plate members includes a first plate member 11, a second plate member 12, and a third plate member 13.

The first plate member 11 is formed of 610 N / mm ² grade high-strength steel having a tensile strength of 610 N / mm ² or more. The first plate member 11 has a substantially rectangular shape in a plan view. The plate thickness of the first plate member 11 is 50 mm, that is, the plate thickness exceeds a legal upper limit value described later.

The second plate member 12 is formed of 780 N / mm ² class high-strength steel having a tensile strength of 780 N / mm ² or more. That is, the tensile strength of the second plate member 12 is larger than the tensile strength of the first plate member 11. The second plate member 12 has a substantially trapezoidal shape in which the length of the first end face facing the first plate member 11 is shorter than the length of the second end face 12b facing the third plate member 13 in plan view. The plate thickness of the second plate member 12 is set to 50 mm, that is, a plate thickness exceeding the legal upper limit value described below, excluding the peripheral edge portion 12a described below.

The third plate member 13 is formed of 780 N / mm ² class high-strength steel having a tensile strength of 780 N / mm ² or more. That is, the tensile strength of the third plate member 13 is larger than the tensile strength of the first plate member 11. The third plate member 13 has a substantially rectangular shape in a plan view. The plate thickness of the third plate member 13 is 38 mm, that is, the plate thickness is not more than the legal upper limit value described later.

  As shown in FIG. 1, the first plate member 11 forms a bottom portion 10A and a top portion 10B of the gas holder 1. The third plate member 13 forms a side portion 10C arranged at the central portion of the gas holder 1 in the vertical direction. The second plate member 12 is arranged between the first plate member 11 (bottom part 10A and top part 10B) and the third plate member 13 (side part 10C). That is, the first plate member 11 (bottom portion 10A and top portion 10B) is attached to the third plate member 13 (side portion 10C) via the second plate member 12.

  As shown in FIG. 2, the bottom portion 10A is composed of three first plate members 11. In the bottom portion 10A, the three first plate members 11 are arranged such that their long sides are adjacent to each other. The bottom portion 10A has a substantially square shape in a plan view. The end faces of the first plate member 11 in the longitudinal direction are joined (butt welding). Of the first plate material 11 of the bottom portion 10A, the first plate material 11 arranged at the center becomes the first nozzle mounting plate material 15A in which the nozzles 20 and 21 are provided.

  The nozzle 20 is provided at the center of the first nozzle mounting plate member 15A. The nozzle 20 is a manhole for workers to enter and leave. The pair of nozzles 21 are provided on the first nozzle mounting plate member 15A with the nozzle 20 interposed therebetween. The nozzle 21 is a supply / discharge nozzle for supplying / discharging high-pressure gas.

The nozzles 20 and 21 are formed by forging 610 N / mm ² grade high-strength steel having a tensile strength of 610 N / mm ² or more. That is, the tensile strength of the nozzles 20 and 21 is the same as the tensile strength of the first plate member 11.

  As shown in FIG. 3, the nozzles 20 and 21 are joined to the first nozzle mounting plate member 15A while protruding outward from the outer surface of the first nozzle mounting plate member 15A. The nozzles 20 and 21 and the first nozzle mounting plate member 15A are welded and integrated in a factory.

  The second plate member 12 is arranged so as to surround the bottom portion 10A. As shown in FIG. 2, in the present embodiment, the four second plate members 12 are arranged so as to respectively adjoin each side of the substantially square-shaped bottom portion 10A in plan view. The lower end faces of the four second plate members 12 (first end faces facing the first plate member 11) are joined (butt welded) to the outer end faces of the first plate member 11 forming the bottom portion 10A. Further, the end faces of the second plate member 12 that are adjacent to each other in the circumferential direction of the gas holder 1 are also joined (butt welding).

  The first annealed portion 17A is formed by joining the three first plate members 11 and the four second plate members 12 as described above. 17 A of 1st annealing parts are put into an annealing furnace and heat-processed (annealing process). As a result, the stress of all welded portions formed in the first annealed portion 17A is removed.

  As shown in FIG. 4, the top portion 10B is also composed of the three first plate members 11. In the top portion 10B, the three first plate members 11 are arranged such that their long sides are adjacent to each other. The top portion 10B has a substantially square shape in a plan view. The end faces of the first plate member 11 in the longitudinal direction are joined (butt welding). Of the first plate material 11 of the top portion 10B, the first plate material 11 arranged at the center becomes the second nozzle mounting plate material 15B in which the nozzles 20 and 22 are provided.

  The nozzle 20 is provided at the center of the second nozzle mounting plate member 15B. The plurality of nozzles 22 are provided on the second nozzle mounting plate member 15B so as to surround the nozzles 20. The nozzle 22 is a safety valve nozzle.

The nozzles 20 and 22 are formed by forging 610 N / mm ² grade high-strength steel having a tensile strength of 610 N / mm ² or more. That is, the tensile strength of the nozzles 20 and 22 is equivalent to the tensile strength of the first plate member 11.

  The nozzles 20 and 22 are joined to the second nozzle mounting plate member 15B while protruding outward from the outer surface of the second nozzle mounting plate member 15B. The nozzles 20 and 22 and the second nozzle mounting plate material 15B are welded and integrated in a factory.

  Also in the top portion 10B, the second plate member 12 is arranged so as to surround the top portion 10B. In the present embodiment, the four second plate members 12 are arranged so as to respectively adjoin each side of the substantially square-shaped top portion 10B in plan view. The upper end surfaces (first end surfaces facing the first plate material 11) of the four second plate materials 12 are joined (butt welded) to the outer end surfaces of the first plate material 11 forming the top portion 10B. Further, the end faces of the second plate member 12 that are adjacent to each other in the circumferential direction of the gas holder 1 are also joined (butt welding).

  The second annealed portion 17B is formed by joining the three first plate members 11 and the four second plate members 12 as described above. The 2nd annealing part 17B is put into an annealing furnace and heat-processed (annealing process). As a result, the stress of all welded portions formed in the second annealed portion 17B is removed.

  As shown in FIG. 1, the side portion 10C includes a plurality of third plate members 13. In the present embodiment, 16 third plate members 13 are arranged so as to be adjacent to each other in the circumferential direction of the gas holder 1.

  The end surfaces of the third plate member 13 that are adjacent to each other in the circumferential direction of the gas holder 1 are joined (butt welded) to each other. Further, the lower end surface of the third plate material 13 is joined (butt welded) to the upper end surface (the second end surface 12b facing the third plate material 13) of the second plate material 12 forming the first annealed portion 17A. The upper end surface of the third plate material 13 is joined (butt welding) to the lower end surface of the second plate material 12 (the second end surface 12b facing the third plate material 13) forming the second annealed portion 17B. The welding of the second plate material and the third plate material 13 and the welding of the third plate materials are performed at the construction site.

  In order to perform the butt welding of the second plate member 12 and the third plate member 13, the plate thickness at the second end surface 12b of the second plate member 12 is set to 38 mm (that is, equivalent to the plate thickness of the third plate member 13). More specifically, as shown in FIGS. 3 and 5, the second plate member 12 has a tapered peripheral edge portion 12a whose plate thickness gradually decreases toward the end face 12b. The outer surface of the peripheral portion 12a (the surface in contact with the atmosphere) is inclined toward the inner side in the radial direction of the gas holder 1 toward the end surface 12b.

  As shown in FIG. 5, grooves are formed on both surfaces of the end portions of the second plate member 12 and the third plate member 13. When the end faces of the second plate member 12 and the third plate member 13 and the end faces of the third plate member 13 are butt-welded at a construction site, the end portions of the second plate member 12 and the third plate member 13 are heated to 150 ° C. with a gas burner or the like. After preheating as described above, double-sided multilayer welding is performed by covered arc welding or the like to form the welded portion 16.

  Here, the relationship between the necessity of heat treatment after welding and the plate thickness of the plate material forming the gas holder 1 will be described. Article 29 of the Regulations for Specified Equipment Inspection stipulated under the High Pressure Gas Safety Act states that "the welds of specified equipment must be heat-treated after welding by an appropriate method to relieve stress. , This is not the case when it is recognized that it is not necessary to perform stress relief. ” In the "Spherical Gas Holder Guide JGA Finger-104-13; Japan Gas Association", the necessity of heat treatment after welding is stipulated as follows.

In the material of the base material type P number 1 group number 1, 2 or 3 (carbon steel having a tensile strength of 490 N / mm ² grade, carbon steel having a tensile strength of 590 N / mm ² grade) Indicates whether post-weld heat treatment is required according to the regulations of Table 1.

Material whose base material classification is P number 11A-2 or 11B (high-strength steel with a specified minimum tensile strength exceeding 620 N / mm ² and 720 N / mm ² or less, a specified minimum tensile strength exceeding 720 N / mm ² In the case of high-strength steel of 790 N / mm ² or less), the necessity of post-weld heat treatment is specified according to the rules in Table 2.

  That is, when the plate thickness of the plate material is 32 mm or less, or when the plate thickness of the plate material is more than 32 mm and 38 mm or less and preheating is performed at a predetermined temperature, it is necessary to perform heat treatment after welding. There is no. However, even if the plate thickness and the preheating conditions are satisfied, it is necessary to perform heat treatment after welding on the plate member to which the nozzle and the like are attached.

  From the above, the legal upper limit value of the plate thickness (base material thickness) that does not require heat treatment after welding (hereinafter, also simply referred to as “statutory upper limit value”) is 38 mm on condition that preheating is performed at a predetermined temperature. I understand. In other words, when assembling the gas holder 1 by welding a plate material having a plate thickness of 38 mm or less at the welded portion, heat treatment after welding (entire annealing of the gas holder 1) at the construction site is unnecessary.

  In the present embodiment, of the first plate member 11, the first nozzle mounting plate member 15A to which the nozzles 20 and 21 are mounted and the second nozzle mounting plate member 15B to which the nozzles 20 and 22 are mounted are welded regardless of the plate thickness. It is necessary to perform the heat treatment of. Further, regarding the welded portion between the first plate materials 11, the welded portion between the first plate material 11 and the second plate material 12, and the welded portion between the second plate materials 12, the first plate material 11 and / or the second plate material in the welded portion Since the plate thickness of No. 12 exceeds the legal upper limit value, it is necessary to perform heat treatment after welding. Therefore, in the present embodiment, the first nozzle mounting plate material 15A, the second nozzle mounting plate material 15B, and the first annealed portion 17A and the second annealed portion 17B including the above-mentioned welded parts are annealed at the factory. The used heat treatment (annealing treatment) after welding is performed.

  On the other hand, regarding the welded portion between the second plate material 12 and the third plate material 13 and the welding between the third plate materials 13, the plate thickness of the second plate material 12 and / or the third plate material 13 at the welded portion is equal to or less than the legal upper limit value. Therefore, heat treatment after welding is unnecessary. Therefore, at the construction site, the butt welding between the second plate material 12 of the first annealed portion 17A and the second annealed portion 17B and the third plate material 13 and the butt welding between the third plate materials 13 are performed.

  The gas holder 1 according to the present embodiment has an outer shell formed by butt welding of a plurality of plate materials. The plurality of plate members includes a first plate member 11, a second plate member 12, and a third plate member 13. The first plate member 11 has nozzle mounting plate members 15A and 15B in which the nozzles 20, 21, and 22 are integrally provided. The second plate member 12 and the third plate member 13 have greater tensile strength than the first plate member 11. The plate thickness of the first plate member 11 is larger than the legal upper limit value, and the plate thickness of the third plate member 13 is equal to or smaller than the legal upper limit value. The first plate member 11 is attached to the third plate member 13 via the second plate member 12.

While the heat treatment after welding is performed using an annealing furnace for the portion where heat treatment after welding is required by the regulations (that is, all the welded portions configured in the first annealed portion 17A and the second annealed portion 17B) The welding of plate materials that do not require heat treatment after welding (that is, the welding of the second plate material 12 and the third plate material 13 and the welding of the third plate material 13 to each other) is performed at the construction site. As a result, the gas holder 1 can be manufactured without performing the entire annealing of the gas holder 1 at the construction site. Further, as the third plate member 13, by using a plate member having a higher strength than the first plate member 11 and having a plate thickness equal to or less than the legal upper limit value, the storage tank capacity of the gas holder 1 can be increased.
Further, the strength of the nozzles 20, 21, 22 is ensured by using the first plate member 11 having a plate thickness larger than the legal upper limit value as the nozzle mounting plate members 15A, 15B provided with the nozzles 20, 21, 22. You can
Furthermore, by using a plate material having a lower tensile strength than the second plate material 12 and the third plate material 13 as the first plate material 11, the first plate material 11 can be manufactured at low cost.

The plate thickness of the first end face of the second plate member 12 facing the first plate member 11 is equal to the plate thickness of the first plate member 11, and faces the third plate member 13 of the second plate member 12. The plate thickness of the second end surface 12b is equal to the plate thickness of the third plate member 13. The second plate member 12 has a peripheral edge portion 12a whose plate thickness gradually decreases toward the end surface 12b.
Thereby, the second plate member can be welded to each of the first plate member and the third plate member having different plate thicknesses.

  The present invention is not limited to the above-described embodiment described with reference to the drawings, and various modifications can be considered within the technical scope thereof.

  For example, in the above-described embodiment, the plurality of plate members includes the first plate member 11, the second plate member 12, and the third plate member 13. However, the present invention is not limited to this, and between the second plate member 12 and the third plate member 13, a fourth plate member having different tensile strength and plate thickness from other plate members may be provided.

  Further, the plate thicknesses and tensile strengths of the first plate member 11, the second plate member 12, and the third plate member 13 are merely examples, and may be appropriately changed depending on the design of the gas holder 1. Although the gas holder 1 is a spherical shell, the gas holder 1 may have another shape such as a cylinder. Further, the shapes of the first plate member 11, the second plate member 12, and the third plate member 13 are not limited to rectangular or trapezoidal shapes, and may be circular, for example.

  In addition, it is possible to appropriately replace the constituent elements in the above-described embodiments with known constituent elements within the scope of the present invention, and it is also possible to appropriately combine the modified examples.

  DESCRIPTION OF SYMBOLS 1 ... Gas holder (pressure container) 10A ... Bottom part 10B ... Top part 10C ... Side part 11 ... 1st plate material 12 ... 2nd plate material 12a ... Peripheral part 12b ... End surface (2nd end surface) 13 ... 3rd plate material 15A, 15B ... Nozzle Mounting plate material 16 ... Welded portion 17A ... First annealed portion 17B ... Second annealed portion 20, 21, 22 ... Nozzle

Claims (3)

The upper limit of the base material thickness that does not require heat treatment after welding in the welded portion is specified by law, and in a pressure vessel in which an outer shell is formed by butt welding of a plurality of plate materials,
The plurality of plate members includes a first plate member, a second plate member, and a third plate member,
The first plate member has a nozzle mounting plate member integrally provided with a nozzle,
The second plate member and the third plate member have greater tensile strength than the first plate member,
The plate thickness of the first plate member is larger than the upper limit value,
The plate thickness of the third plate material is equal to or less than the upper limit value,
The pressure vessel, wherein the first plate member is attached to the third plate member via the second plate member. Of the second plate member, the plate thickness at the first end face facing the first plate member is equal to the plate thickness of the first plate member,
Of the second plate member, the plate thickness at the second end face facing the third plate member is equal to the plate thickness of the third plate member,
The pressure vessel according to claim 1, wherein the second plate member has a peripheral edge portion whose plate thickness gradually decreases toward the second end face. The first plate member is formed of 610 N / mm ² class high-strength steel having a plate thickness of 50 mm,
The second plate member has a plate thickness of 50 mm at a first end surface facing the first plate member and a plate thickness of 38 mm at a second end surface facing the third plate member is 780 N / mm ² class high-strength steel. Formed,
The pressure vessel according to claim 1 or 2, wherein the third plate member is formed from 780 N / mm ² class high-strength steel having a plate thickness of 38 mm.

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