A method for constructing a fuel tank in a single-hull configuration

Abstract

This invention relates to a method for constructing a fuel tank in a single-hull configuration, comprising the following steps: constructing the fuel tank assembly into double-bottom sections, bulkhead sections, side sections, and deck sections; arranging assembly jigs at the assembly site; hoisting and assembling the fuel tank sections according to the assembly sequence; forming a complete compartment after the fuel tank assembly is completed, and conducting a tightness test by inflating the compartment; after the tightness test, opening process holes in the bulkhead on the side; performing sandblasting and painting work on the interior of the fuel tank; constructing the fuel tank containment system; after the fuel tank containment system is completed, sealing the process holes in the bulkhead, and then hoisting and mounting the entire fuel tank. This invention's method for constructing a fuel tank in a single-hull configuration addresses the characteristics of a single-hull fuel tank, solving the problem of high precision requirements and the susceptibility to deformation in this configuration, thus ensuring the construction precision and integrity of the fuel tank in this single-hull configuration.

Description

Technical Field

[0001] This invention relates to the field of shipbuilding, and more specifically to a method for constructing a fuel tank in a single-hull configuration. Background Technology

[0002] The LNG dual-fuel power conversion project for operating large container ships involves modifying the original fuel system and heavy fuel oil engines to a dual-fuel mode. The ship can now use both LNG and low-sulfur fuel oil. After the conversion, the ship's carbon dioxide and particulate matter emissions will be reduced by more than 90%, significantly reducing the environmental impact of large ships and fully meeting the IMO's sulfur emission limits. The fuel tank is constructed in sections with a single-hull structure, and the containment system is installed in a compact manner. The construction space for the containment system is limited, requiring full-tank tightness testing and hoisting under single-hull conditions. The overall lifting weight is heavy, and the precision requirements for the entire tank are high. The construction difficulty far exceeds that of fuel tanks on other ship types, and there is currently no experience to draw upon for constructing fuel tanks in a single-hull configuration.

[0003] Existing technology CN112591033A discloses a precision control process for converting a ship into a single-hull fuel tank. The specific steps are as follows: Step 1: Using measuring equipment, the Mark 3 type liquid cargo tank is first segmented; Step 2: The single-hull structure after the first segmentation is segmented a second time; Step 3: During the second segmentation, the segmentation status is adjusted in real time; Step 4: Corrective measures are taken to address problems that may arise during segmentation in steps 1 to 3. While it discloses a method for segmenting and correcting the liquid cargo tank as a whole, it does not disclose the specific construction method of the fuel tank. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention provides a method for constructing a fuel tank in a single-hull state. This method addresses the characteristics of a single-hull fuel tank, solving the problem of high precision requirements and the susceptibility to deformation in this state, thus ensuring the construction precision and integrity of the fuel tank in a single-hull state.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A method for constructing a fuel tank in a single-hull configuration, the method comprising the following steps:

[0007] S1, the fuel tank section is constructed by dividing it into double bottom sections, transverse bulkhead sections, side sections, and deck sections;

[0008] S2, Arrange the main group jig in the main group area;

[0009] S3, the assembly of the fuel tank sections according to the overall assembly sequence;

[0010] S4. After the fuel tank section is assembled, a complete compartment is formed. The compartment is then filled with air for a tightness test.

[0011] S5, After the fuel tank tightness test is completed, a bulkhead process hole is opened on the side of the hull;

[0012] S6, to carry out sandblasting and painting work inside the fuel tank;

[0013] S7, Construction of the fuel tank containment system;

[0014] After the S8 fuel tank containment system is completed, the process holes in the bulkhead are sealed, and the fuel tank is hoisted and installed as a whole.

[0015] As a preferred technical solution, in step S1, the fuel tank section is divided into three double bottom sections, four side sections, six transverse bulkhead sections, and three deck sections.

[0016] As a preferred technical solution, in step S2, the bottom of the fuel tank includes longitudinal girder and ribs, the bilge includes platform plate and T-shaped ribs, the bottom longitudinal girder and ribs of the ship are provided with several relief holes, and the bilge support is set at the intersection of the platform plate and the T-shaped ribs.

[0017] As a preferred technical solution, in step S3, the assembly sequence of the fuel tank is as follows: double bottom section, two side sections, six transverse bulkhead sections, two more side sections, and deck section; when positioning the transverse bulkhead sections, the transverse bulkhead sections welded to the side bilges are positioned first; when assembling the deck sections, the deck sections with liquid dome bases and the hull centerline are positioned first, and then the remaining deck sections are hoisted.

[0018] As a preferred technical solution, in step S3, after each segment is positioned, the flatness of the fuel tank wall is measured. The flatness requirement simultaneously meets the requirements that the overall deformation does not exceed the overall size / 800 and the deformation within a local 3m range does not exceed 4mm.

[0019] As a preferred technical solution, in step S4, the fuel tank is constructed as a single-shell structure. Before the test of the tank, finite element calculations are performed on the fuel tank filling test state. The fuel tank filling test is conducted using a pressure of 0.015-0.02 MPa.

[0020] As a preferred technical solution, in step S5, the height of the process hole in the bulkhead is matched with the height of the scaffolding platform of the enclosure system.

[0021] As a preferred technical solution, in step S6, the scaffolding of the enclosure system is surrounded by three-ring cloth before sandblasting and coating.

[0022] As a preferred technical solution, in step S7, resin is applied to the outside of the cabin during the construction of the enclosure system, and then the coated insulation box is transported to the cabin for installation.

[0023] As a preferred technical solution, in step S8, the fuel tank is hoisted using a floating crane, and the fuel tank is hoisted vertically.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] (1) The fuel tank is constructed in a single-hull state, which breaks through the limitations of the fuel tank construction state, which is conducive to the early construction of the fuel tank and reduces the dock conversion cycle;

[0026] (2) By adopting a precision control scheme that integrates design and construction, the flatness of the fuel tank and the squareness of the large tank are controllable, creating favorable conditions for the construction of the enclosure system.

[0027] (3) Through the implementation of the whole-tank sand flushing process, the phosphate primer coating at the section joint is of very good quality and almost no repair is needed, which helps to reduce the use of special paint and reduce paint costs.

[0028] (4) The development of the external enclosure system resin coating platform has expanded the work area inside the tank to the outside, making the installation efficiency of the enclosure system more efficient and providing a strong guarantee for shortening the installation cycle of the fuel tank enclosure system.

[0029] (5) The fuel tank was constructed in a single-hull state with complete integrity and the hoisting accuracy was guaranteed to meet the requirements. Attached Figure Description

[0030] Figure 1 This is a perspective view of the fuel tank in a method for constructing a fuel tank in a single-hull state according to the present invention.

[0031] Figure 2 This is a side view of the overall assembly frame arrangement in a construction method of a fuel tank in a single-hull state according to the present invention;

[0032] Figure 3 This is a general assembly jig layout diagram in a method for constructing a fuel tank in a single-hull state according to the present invention;

[0033] Figure 4 This is a schematic diagram showing the location of the process holes in the fuel tank wall in a method for constructing a fuel tank in a single-hull state according to the present invention.

[0034] Figure 5 This is a scaffolding layout diagram of the enclosure system in a method for constructing a fuel tank in a single-hull state according to the present invention;

[0035] Figure 6 This is a schematic diagram of the overall hoisting of the fuel tank in a construction method of a fuel tank in a single-hull state according to the present invention.

[0036] In the diagram: 1. Fuel tank; 2. Double bottom section; 3. Side section; 4. Stern transverse bulkhead section; 5. Bow transverse bulkhead section; 6. Deck section; 7. Containment system scaffolding; 8. Bulkhead process openings; 9. Assembly dock pier; 10. Assembly support; 11. Floating crane; 12. Lifting sling; 13. Platform plate; 14. Ribs. Detailed Implementation

[0037] The technical solution of the present invention will be further described below with reference to specific embodiments:

[0038] like Figure 1-6 As shown, a method for constructing a fuel tank 1 in a single-hull configuration includes the following steps:

[0039] S1. Based on the equipment and facilities of the sectional construction site and the principle of being conducive to precision control, the fuel tank 1 section is divided into three double-bottom sections 2, four side sections 3, three stern transverse bulkhead sections 4, three bow transverse bulkhead sections 5, and three deck sections 6. The three double-bottom sections 2 are located in the lower part of the fuel tank 1 section, the three deck sections 6 are located in the upper part of the fuel tank 1 section, the four side sections 3 are distributed in pairs on both sides of the fuel tank 1 section, the three stern transverse bulkhead sections 4 are located in the stern of the fuel tank 1 section, and the three bow transverse bulkhead sections 5 are located in the bow of the fuel tank 1 section.

[0040] S2, Arrange a reasonable assembly frame in the assembly site. The bottom of the fuel tank 1 includes longitudinal girder and rib plate. The side bilge includes platform plate 13 and T-shaped rib 14. The bottom longitudinal girder and rib plate of the ship are provided with several lightening holes. The bilge support is set at the intersection of platform plate 13 and T-shaped rib 14. Place the assembly dock 9 and support in place.

[0041] S3. The assembly of fuel tank section 1 will proceed according to the following sequence: three double-bottom sections 2, two side sections 3, three stern transverse bulkhead sections 4, three bow transverse bulkhead sections 5, two more side sections 3, and deck section 6. When positioning the transverse bulkhead sections, those welded to the bilge sections will be positioned first. During the assembly of deck section 6, the section with the liquid dome base and hull centerline will be positioned first, followed by the hoisting of the remaining deck sections 6. Before assembling deck section 6, the containment system scaffolding 7 should be hoisted into fuel tank 1. Simultaneously, after each section is positioned, the flatness of the fuel tank 1 bulkhead surface should be measured. The flatness requirements must simultaneously meet the following conditions: overall deformation not exceeding one-thousandth of the overall dimensions and local deformation within a 3m range not exceeding 4mm.

[0042] S4. After the assembly of fuel tank 1 is completed, a single-shell structure is formed in the compartment. The compartment is filled with air for a tightness test. The Patran software is used to perform finite element calculations on the fuel tank 1 filling test state to prevent the internal pressure from squeezing the fuel tank wall during the filling process and causing the fuel tank deformation to exceed the allowable value. The fuel tank 1 filling test is carried out with a pressure of 0.015-0.02 MPa.

[0043] S5. After the tightness test of fuel tank 1 is completed, a bulkhead process hole 8 is opened on the side of the hull. The height of the bulkhead process hole 8 is matched with the height of the enclosure system scaffolding platform 7. The bulkhead process hole 8 is a temporary passage for personnel and materials to enter and exit during the construction of the enclosure system inside the fuel tank. The size of the bulkhead process hole should meet the needs of the equipment used for the installation of the enclosure system. The enclosure system scaffolding platform 7 has multiple layers, and the bulkhead process hole 8 is at the same height as one of the layers of the enclosure system scaffolding platform 7.

[0044] S6. Use three-ring cloth to surround the scaffolding 7 of the internal enclosure system of fuel tank 1 for protection, and then carry out the sandblasting and painting work inside fuel tank 1.

[0045] S7, Construction of the containment system inside fuel tank 1; The resin coating platform for the containment system is erected outside fuel tank 1 according to the erection drawing. During the construction of the containment system, the resin coating of the insulation box is carried out on the resin coating platform, and then the coated insulation box is transported to the tank for installation.

[0046] S8. After the construction of the containment system of fuel tank 1 is completed, the process opening 8 of the bulkhead is sealed. The fuel tank 1 is then hoisted onto the ship by the floating crane 11. During the hoisting of the fuel tank 1, vertical hoisting is ensured.

[0047] This embodiment is merely a further explanation of the present invention and is not intended to limit the present invention. Those skilled in the art can make non-inventive modifications to this embodiment as needed after reading this specification, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A method for constructing a fuel tank in a single-hull configuration, characterized in that, The method includes the following steps: S1, the fuel tank section is constructed by dividing it into double bottom sections, transverse bulkhead sections, side sections, and deck sections; S2, Arrange the main group jig in the main group area; S3. The fuel tank sections are assembled and hoisted according to the overall assembly sequence. The assembly sequence of the fuel tanks is as follows: double bottom section, two side sections, six transverse bulkhead sections, two more side sections, and deck sections. When positioning the transverse bulkhead sections, the sections welded to the side bilges are positioned first. When assembling the deck sections, the deck sections with liquid dome bases and the hull centerline are positioned first, and then the remaining deck sections are hoisted. S4. After the fuel tank section is assembled, a complete compartment is formed. The compartment is then filled with air for a tightness test. S5, After the fuel tank tightness test is completed, a bulkhead process hole is opened on the side of the hull; S6, to carry out sandblasting and painting work inside the fuel tank; S7, Construction of the fuel tank containment system; After the S8 fuel tank containment system is completed, the process holes in the bulkhead are sealed, and the fuel tank is hoisted and installed as a whole.

2. The method for constructing a fuel tank in a single-hull state according to claim 1, characterized in that, In step S1, the fuel tank section is divided into three double bottom sections, four side sections, six transverse bulkhead sections and three deck sections. The six transverse bulkhead sections are further divided into three stern transverse bulkhead sections and three bow transverse bulkhead sections.

3. The method for constructing a fuel tank in a single-hull state according to claim 1, characterized in that, In step S2, the bottom of the fuel tank includes longitudinal girder and ribs, and the side bilge includes platform plate and T-shaped ribs. The bottom longitudinal girder and ribs of the ship are provided with several relief holes, and the side bilge is supported at the intersection of the platform plate and the T-shaped ribs.

4. The method for constructing a fuel tank in a single-hull state according to claim 1, characterized in that, In step S3, after each segment is positioned, the flatness of the fuel tank wall is measured. The flatness requirement is that the overall deformation does not exceed one-thousandth of the overall size and the deformation within a local 3m range does not exceed 4mm.

5. A method for constructing a fuel tank in a single-hull configuration according to claim 1, characterized in that, In step S4, the fuel tank is constructed as a single-shell structure. Before the tank test, finite element calculations are performed on the fuel tank filling test state. The fuel tank filling test is conducted using a pressure of 0.015-0.02 MPa.

6. The method for constructing a fuel tank in a single-hull state according to claim 1, characterized in that, In step S5, the height of the bulkhead process opening is matched with the height of the enclosure system scaffolding platform.

7. The method for constructing a fuel tank in a single-hull state according to claim 1, characterized in that, In step S6, the scaffolding of the enclosure system is surrounded by three-ring fabric before sandblasting and coating.

8. The method for constructing a fuel tank in a single-hull configuration according to claim 1, characterized in that, In step S7, during the construction of the enclosure system, resin is applied to the outside of the cabin, and then the coated insulation box is transported to the cabin for installation.

9. The method for constructing a fuel tank in a single-hull configuration according to claim 1, characterized in that, In step S8, the fuel tank is lifted using a floating crane, ensuring vertical lifting during the process.

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