A construction method for open-air methanol tanks of oil tankers based on four-quadrant modular assembly

Abstract

This invention discloses a method for constructing an open-air methanol tanker on an oil tanker based on a four-quadrant segmented assembly. The steps include: S1, segmented four-quadrant division; S2, synchronous prefabrication of panels; S3, parallel segmented molding; S4, overall assembly of the tank; S5, integrated completion testing and pre-assembly; S6, special coating application to the tank; and S7, assembly and deployment of the entire module onto the ship. This invention achieves standardized parallel production of segments through symmetrical four-quadrant segmentation. The assembly forms a complete enclosed tank, and all testing, pre-assembly, and special coating processes are completed on the ground, significantly reducing the dry dock operation cycle and improving construction accuracy and safety.

Description

Technical Field

[0001] This invention relates to the field of shipbuilding technology, specifically to a method for constructing an open-air methanol tank for an oil tanker based on a four-quadrant modular assembly. Background Technology

[0002] With the increasing requirements for low-carbon emission reduction in ships, methanol dual-fuel tankers are gradually becoming more common. Current methanol tank construction processes generally divide the methanol tank into several irregularly shaped planar sections with significant differences in size and weight, which are then assembled section by section in the dry dock. This traditional process has many drawbacks: First, it cannot achieve parallel assembly line operations. The differences in shape and weight of each section are significant, the jigs cannot be standardized and reused, and the distribution of construction teams, lifting, and welding equipment is uneven, which easily leads to bottlenecks in single-section processes and prolongs the overall construction cycle. Second, the dockside operation cycle is long. Many processes such as compartment tightness testing, strength testing, equipment and pipeline installation, and special coating of compartments must be carried out in the dock or wharf stage, with multiple trades working at the same time, resulting in low construction efficiency. Third, quality control is difficult. After the sections are assembled in the dock, they form a closed and narrow compartment. Problems such as pressure test leaks, welding deformation, and coating defects can only be reworked in a small space, which is difficult and costly to repair. Fourth, the operating safety conditions are poor. High-risk operations such as pressure testing, sandblasting, and painting are carried out in high-altitude and closed compartments in the dock. Multiple operations interfere with each other, resulting in great pressure on safety control. While existing technologies include some related processes such as modular assembly and pre-assembly outside the dock, they employ a method of splitting along the bow and stern along the ship's length and layering along the cabin height, which cannot fundamentally solve the pain points of existing processes.

[0003] Therefore, it is necessary to provide a construction method for open methanol tankers on oil tankers based on four-quadrant segmented assembly to solve the above-mentioned technical problems. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a construction method for open-air methanol tanks on oil tankers based on four-quadrant segmented assembly. This method achieves standardized parallel production of segments through symmetrical four-quadrant segmentation, and the assembly forms a complete enclosed tank. All testing, pre-assembly, and special coating processes are completed on the ground, significantly reducing the dry dock operation cycle and improving construction accuracy and safety.

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

[0006] A method for constructing an open methanol tanker for oil tankers based on a four-quadrant modular assembly includes the following steps:

[0007] S1. Segmented Four-Quadrant Division: The open rectangular methanol fuel tank of the oil tanker is divided into four independent segments with similar structure, external dimensions and self-weight by making a cross-shaped division along the centerline of the length direction and the centerline of the width direction: the left aft segment, the right aft segment, the left front segment, and the right front segment.

[0008] S2. Synchronous Prefabrication of Panels: Prefabricate the four sets of panel frames corresponding to each segment, namely the bottom panel frame, side panel frame, front or rear panel frame, and top panel frame, respectively, at the group or middle assembly site. During the panel prefabrication stage, the pre-outfitting of piping systems, outfitting components, and cables is completed simultaneously.

[0009] S3. Segmented Parallel Forming: Standardized segmented construction special jigs are set up. Using the side panel frame as the assembly benchmark, the bottom panel frame, front or rear panel frame, and top panel frame are hoisted in sequence for assembly and welding. The four segments are constructed simultaneously in a completely parallel operation mode.

[0010] S4. Overall assembly of the compartment: A special assembly jig is set up at the assembly site. The sections that are placed on the side are turned over and adjusted to the normal position. The four sections are hoisted in sequence, precisely positioned, and welded together to form a complete and independent methanol tank body with a closed structure.

[0011] S5. Integrated Completion Test and Pre-installation: Conduct chamber tightness test and chamber strength test in sequence on the closed and complete methanol tank at the main assembly site, and simultaneously complete the remaining installation work of equipment, pipelines, cables and outfitting components inside the tank;

[0012] S6. Special coating construction for the cabin: Sandblasting and polishing the interior of the methanol cabin to complete the special coating construction, coating inspection and repair of coating defects;

[0013] S7: Overall module assembly: A large gantry crane is used to hoist the completed methanol tank module to the pre-set installation area on the tanker deck in the dry dock. After positioning, it is welded and fixed to the main hull deck structure, completing the connection of pipelines, cables and outfitting components between the tank and the main hull.

[0014] Preferably, the four segments in step S1 are symmetrical structures, and the segment construction jigs for the four segments use the same set of standardized tooling, eliminating the need for custom-made irregular jigs.

[0015] Preferably, in step S3, the prefabrication, assembly and welding processes of the sheet are carried out simultaneously in the four segments, and each segment is equipped with an equal number of construction teams, lifting equipment and welding equipment to achieve balanced assembly line operation.

[0016] Preferably, after the methanol tank is assembled in step S4, the sides, top, and bottom are completely sealed, and the airtightness and strength of the entire tank can be tested independently at the assembly site.

[0017] Preferably, in step S5, the tightness test, strength test, equipment pre-assembly, and pipeline and electrical outfitting are all completed at the general assembly site. After the methanol tank is hoisted onto the ship as a whole, only structural docking and pipeline and electrical connection are performed to form a plug-and-play functional module.

[0018] Preferably, the sandblasting and special coating operations in step S6 are carried out in an open area of ​​the general group, and the work is reported and repaired in a unified manner after completion, so as to avoid the complex and cross-operation environment of various trades in the dock stage.

[0019] Preferably, the methanol tank is an open-air, independent methanol fuel tank located in the deck area of ​​an oil tanker.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. Achieve standardized, balanced, and parallel production to improve construction efficiency: The four-quadrant division scheme with a cross-shaped centerline is adopted, and the structure, size, weight, and height of the four segments are highly uniform. The segment jigs are standardized and universal, eliminating the need for customized non-standard tooling. The four segments can be prefabricated and assembled simultaneously, and manpower, lifting, and welding equipment are evenly distributed to form a stable assembly line operation mode, significantly shortening the total construction period of the segments.

[0022] 2. Improve the construction precision of the hull and reduce the difficulty of quality control: When assembling and welding individual four-quadrant sections on a special jig, the flatness, verticality and overall dimensional accuracy of the wall panels can be controlled; after assembly, a complete closed hull is formed, and leaks, coating damage and outfitting errors can be rectified in an open ground area, avoiding the high-difficulty rework in the small compartments after boarding, thus reducing the difficulty of quality control.

[0023] 3. Significantly shorten the dry dock construction cycle and release the core capacity of the dry dock: This invention transfers all key processes such as tightness test, strength test, pre-installation of all equipment in the cabin, and special sandblasting and coating of the cabin to the ground site of the general assembly. After the methanol tank is hoisted onto the ship, only the hull structure welding and pipeline and cable connection need to be completed, which greatly reduces the amount of cross-operations in the dry dock, compresses the critical path cycle of the dry dock, and improves the overall capacity of the shipyard.

[0024] 4. Optimize the construction environment and improve the level of work safety: High-risk processes such as pressure testing, sandblasting, and special coating are all transferred to the open assembly area, where ventilation, fire protection, and protection conditions are better than in the small and enclosed space of the dock; the high-altitude cross-operations in the dock are reduced, and the difficulty of on-site safety management is greatly reduced. Attached Figure Description

[0025] Figure 1 These are three views illustrating the four-quadrant symmetrical segmentation of the methanol tank according to the present invention.

[0026] Figure 2 This is a schematic diagram of the structure of the four sets of plate frame panels in this invention.

[0027] Figure 3 This is a schematic diagram of the four independent segments in this invention.

[0028] Figure 4 This is a schematic diagram of the structure of the methanol tank that is completely sealed after the four sections are assembled together in this invention.

[0029] Figure 5 This is a flowchart of the overall construction process of the present invention.

[0030] Among them, 1-left rear section, 2-right rear section, 3-left front section, 4-right front section, 5-front or rear panel frame, 6-side panel frame, 7-top panel frame, 8-bottom panel frame. Detailed Implementation

[0031] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and not for limiting the scope of the invention. After reading this invention, any modifications of the invention in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0032] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixed connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0033] In this invention, terms such as "upper," "lower," "bottom," and "top" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are merely relational terms determined for the convenience of describing the structural relationship of the various components or elements of this invention, and do not specifically refer to any component or element in this invention, and should not be construed as limiting this invention.

[0034] like Figures 1 to 5 As shown, this embodiment takes the construction of an open rectangular methanol fuel tank on the deck of a 114,200 DWT methanol dual-fuel tanker as an example.

[0035] S1. Segmented four-quadrant division: such as Figure 1 As shown, the rectangular open-air methanol tank is divided into four independent sections with similar dimensions and weights by cross-shaped divisions along the centerlines of its length and width: left rear section 1, right rear section 2, left front section 3, and right front section 4. The four sections can share the same standardized construction jig, eliminating the need for separately designed irregular tooling.

[0036] S2. Synchronous Prefabrication of Panels: Four types of panel prefabrication are carried out simultaneously at the small or medium assembly site: front or rear panel frame 5, side panel frame 6, top panel frame 7, and bottom panel frame 8. During the panel prefabrication stage, the pre-outfitting of piping systems, outfitting components, and cable trays on them is completed simultaneously, realizing the pre-outfitting process; the structural forms of each panel frame are standardized, and the work process is unified during batch prefabrication.

[0037] S3. Segmented Parallel Construction: A standardized segmented jig is erected, and the four segments are constructed simultaneously in a completely parallel operation mode. Specifically, the left rear segment 1 and right rear segment 2 are assembled from the rear panel frame, side panel frame, top panel frame, and bottom panel frame; the left front segment 3 and right front segment 4 are assembled from the front panel frame, side panel frame, top panel frame, and bottom panel frame. Using the side panel frame 6 as the assembly benchmark, the bottom panel frame 8, front or rear panel frame 5, and top panel frame 7 are hoisted sequentially for positioning, assembly, and welding, thus forming the left rear segment 1, right rear segment 2, left front segment 3, and right front segment 4 respectively. Construction teams, lifting equipment, and welding resources are evenly allocated, eliminating bottlenecks in the segmented construction process.

[0038] S4. Overall Assembly of the Chamber: A dedicated methanol tank assembly frame is set up at the assembly site, and the following assembly procedures are performed: The left rear section 1, which is in a side position, is turned over and adjusted to a normal position using a gantry crane, and then hoisted into place on the assembly frame. Anti-tipping devices are installed for temporary fixation. Using the same turning and hoisting process, the right rear section 2, left front section 3, and right front section 4 are hoisted to the assembly frame in sequence. The four sections are then finely adjusted, positioned, and welded together to finally form a complete and independent methanol tank body that is closed on all six sides and structurally sealed.

[0039] S5. Integrated Completion Test and Pre-assembly: After the assembly is completed to form a closed cabin, integrated completion work is carried out at the ground assembly site: the cabin hydrostatic strength test and airtightness test are carried out in sequence; leaks and welding defects found during the test are rectified directly in an open area; the remaining piping, cables and outfitting components are installed simultaneously.

[0040] S6. Special coating construction for the cabin: The inner wall of the methanol cabin is sandblasted and polished to meet the technical requirements for methanol cabin coating construction. After the coating is cured, the coating is inspected. If any defects are found, they are all repaired at the general assembly site to avoid the complex cross-operation environment of various trades during the dock phase.

[0041] S7. Assembly of the complete module: Remove all temporary tooling and auxiliary components outside the tank body, and use a large gantry crane to hoist the completed methanol tank module to the pre-set installation area on the tanker deck in the dry dock; after positioning and calibration, weld and fix it to the main hull structure of the deck, and complete the connection of pipelines, cables and outfitting components between the methanol tank module and the main hull.

[0042] The foregoing description illustrates and describes preferred embodiments of the present invention. As previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A method for constructing an open-air methanol tanker for an oil tanker based on a four-quadrant modular assembly, characterized in that, Includes the following steps: S1. Segmentation into four quadrants: The open rectangular methanol fuel tank of the oil tanker is divided into four independent segments with similar structure, external dimensions and self-weight: left rear segment (1), right rear segment (2), left front segment (3), and right front segment (4) by making a cross-shaped division along the centerline of the length direction and the centerline of the width direction. S2. Synchronous prefabrication of panels: Prefabricate the front or rear panel frame (5), side panel frame (6), top panel frame (7), and bottom panel frame (8) of each segment at the group or middle assembly site. Simultaneously complete the pre-outfitting of piping system, outfitting parts, and cables during the panel prefabrication stage. S3. Segmented Parallel Forming: Standardized segmented construction special jigs are set up. Using the side panel frame as the assembly benchmark, the bottom panel frame, front or rear panel frame, and top panel frame are hoisted in sequence for assembly and welding. The four segments are constructed simultaneously in a completely parallel operation mode. S4. Overall assembly of the compartment: A special assembly jig is set up at the assembly site. The sections that are placed on the side are turned over and adjusted to the normal position. The four sections are hoisted in sequence, precisely positioned, and welded together to form a complete and independent methanol tank body with a closed structure. S5. Integrated Completion Test and Pre-installation: Conduct chamber tightness test and chamber strength test in sequence on the closed and complete methanol tank at the main assembly site, and simultaneously complete the remaining installation work of equipment, pipelines, cables and outfitting components inside the tank; S6. Special coating construction for the cabin: Sandblasting and polishing the interior of the methanol cabin to complete the special coating construction, coating inspection and repair of coating defects; S7: Overall module assembly: A large gantry crane is used to hoist the completed methanol tank module to the pre-set installation area on the tanker deck in the dry dock. After positioning, it is welded and fixed to the main hull deck structure, completing the connection of pipelines, cables and outfitting components between the tank and the main hull.

2. The method for constructing an open-air methanol tanker for an oil tanker based on a four-quadrant segmented assembly, as described in claim 1, is characterized in that: In step S1, the four segments are symmetrical structures, and the same set of standardized tooling is used for the segment construction jigs of the four segments, so there is no need to customize irregular jigs separately.

3. The method for constructing an open-air methanol tanker for an oil tanker based on a four-quadrant modular assembly as described in claim 1, characterized in that: In step S3, the prefabrication, assembly and welding processes of the sheet are carried out simultaneously in the four sections. Each section is equipped with an equal number of construction teams, lifting equipment and welding equipment to achieve balanced assembly line operation.

4. The method for constructing an open-air methanol tanker for an oil tanker based on a four-quadrant segmented assembly as described in claim 1, characterized in that: After the assembly in step S4 is completed, the methanol tank is completely sealed on all sides, top and bottom, and the airtightness and strength of the entire tank can be tested independently at the assembly site.

5. The method for constructing an open-air methanol tanker for an oil tanker based on a four-quadrant segmented assembly, as described in claim 1, is characterized in that: In step S5, the tightness test, strength test, equipment pre-assembly, and pipeline and electrical outfitting are all completed at the general assembly site. After the methanol tank is hoisted onto the ship as a whole, only the structural docking and pipeline and electrical connection are carried out to form a plug-and-play functional module.

6. The method for constructing an open-air methanol tanker for an oil tanker based on a four-quadrant modular assembly as described in claim 1, characterized in that: In step S6, sandblasting and special coating operations are carried out in an open area of ​​the main group, and inspection and repair are carried out in a unified manner after the operation is completed.

7. The method for constructing an open-air methanol tank for an oil tanker based on a four-quadrant modular assembly as described in claim 1, characterized in that: The methanol tank is an open-air, independent methanol fuel tank located in the deck area of ​​an oil tanker.

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