Marine main engine replacement method

Abstract

The invention provides a marine main engine replacement method, and belongs to the technical field of ship building and repairing. In the floating state of a ship, according to the real ship environment and the parameters such as the size and tonnage of a main engine, a first process hole is additionally formed in the front wall of an engine room, the space of the cabin is utilized to the limit, and a longitudinal crane crossing the engine room and a cargo hold is installed to serve as a channel for the main engine to enter and exit from the engine room; a main engine is split into several main parts, and new and old main engines enter and exit from a cabin by means of crane hoisting, so that replacement operation of the main engines is completed. The marine main engine replacement method has the advantages of being low in cost, short in period, safe and reliable in process, free of original system disassembly and assembly risks and few in additional project.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ship repair, in particular to a ship main engine replacement method. BACKGROUND

[0002] With the acceleration of the decarbonization process of the shipping industry, the new ship market gradually turns to dual-fuel engines. Large dual-fuel container ships are one of the high-value-added ship types and market mainstream ship types. Dual-fuel ships refer to the mode of operation that can arbitrarily select clean energy fuels (such as LNG, methanol, ammonia, etc.) or traditional fuels. Retrofitting existing ships is an important step towards more environmentally friendly and more economical, and dual-fuel retrofitting of existing ships is the focus of competition for shipbuilding companies around the world. After the ship is completed, it can reduce greenhouse gas emissions every year. Dual-fuel retrofitting of ships has great market potential, and ship main engine replacement is a topic that cannot be avoided in dual-fuel retrofitting projects.

[0003] The conventional ship main engine replacement adopts a scheme of temporarily lifting the living area away, entering the cabin from the top, or a scheme of entering the cabin through a slide hole opened in the front wall of the engine room. Among them, the top cabin entry scheme needs to completely remove the living area, the living area has large tonnage, high requirements for lifting equipment and bearing site, and there are huge amount of pipes and circuits in the living area, and there are risks in the later original system disassembly and debugging; the slide hole cabin entry scheme needs to suspend the engine room counter-top at the upper part of the main engine, and the construction has safety risks, the engine room bottom unit machine, pipe and electric disassembly has large engineering quantity, and there are risks in the later original system disassembly and debugging. Although the conventional scheme has advantages such as mature scheme, many successful cases, etc., there are many restricting factors, many hardware limitation conditions, high construction difficulty, long cycle, etc. SUMMARY

[0004] In view of the deficiencies in the prior art, the present application provides a safe and efficient ship main engine replacement method for replacing the dual-fuel main engine and the old main engine. In the floating state of the ship, according to the parameters such as the real ship environment and the main engine size and tonnage, a temporary process hole is opened in the front wall of the engine room, the cabin space is maximally utilized, and a temporary large-tonnage crane is installed; the new and old main engines are lifted in and out of the engine room by the crane, thereby completing the replacement of the main engine.

[0005] The present application achieves the above technical purpose by the following technical means.

[0006] A ship main engine replacement method, characterized in that it comprises the following steps: (1) Measuring the old main engine top net height data of the real ship: scanning the original ship engine room by 3D, lofting the new main engine, confirming the new main engine top net height data, and ensuring that the space meets the space requirement of the main engine entering and leaving the engine room at the engine room front wall as a transfer channel; (2) Determine the new main engine factory scheme: intervene in the supply stage of the main engine parts in advance, and confirm the disassembly and shipment state of the new main engine to the ship factory with the ship owner and the main engine manufacturer; (3) Longitudinal crane design: according to the disassembly scheme, lifting point setting, size, weight, minimum lifting height, distance of barge transportation and space of the ship engine room of the old and new main engine, the size, bearing capacity, fastening and installation method of the longitudinal crane are designed; (4) Opening process holes, removing internal parts of the main engine barge transportation channel: according to the size and tonnage of the new and old main engine, the size of the longitudinal crane and the equipment, pipelines, supports of the engine room front wall, a first process hole is opened in the engine room front wall, and a second process hole is started on the deck at the top of the ship cargo hold; the pipelines, cables, supports of the engine room deck counter top part are removed, the deck counter top height is lowered, and the equipment, pipelines, fittings in the main engine barge transportation channel are removed to prepare for the installation of the longitudinal crane; (5) Installation of longitudinal and transverse cranes: the longitudinal crane is installed along the front and rear center axis of the ship and symmetrically on the channel of the ship cargo hold and engine room, and the transverse crane and hoisting equipment are installed at the first process hole; (6) Old main engine removal: after removing the pipelines and circuits connected to the old main engine, the old main engine is disassembled in batches and lifted out of the engine room by the longitudinal crane, enters the cargo hold through the first process hole, and is lifted out of the warehouse by the transverse crane; (7) New main engine lifting: the new main engine is shipped to the shipyard according to the state of step (2), lifted to the engine room in batches by the transverse crane and longitudinal crane, and assembled; (8) After the new main engine is assembled, the new equipment, pipelines, circuits, supports, fittings related to the new main engine are installed in the engine room, and the first and second process holes are repaired.

[0007] Further, the new main engine is a dual-fuel main engine, and in step (2), the determined new main engine delivery scheme is to deliver the main engine into four parts of the main frame, the crankshaft, the frame box and the top structure to the shipyard.

[0008] Further, in the process of step (3) longitudinal crane design, finite element analysis is used to establish a database model, simulate the crane walking process, and confirm the stability and reliability of the crane girder by calculating the structural strength of the girder through finite element analysis. At the same time, the safety and reliability of the ship structure are confirmed through mechanical transmission calculation.

[0009] Further, in step (3) longitudinal crane design, the following technical requirements are met: The lifting height of the hook reaches more than 17.4m from the baseline; It has 2 independently movable main hooks, and the lifting tonnage of the main hook is more than 60T; the double-hook tandem lifting tonnage of a single crane is 120T; if the old main engine parts cannot be disassembled, the lifting tonnage of the main hook needs to be increased to 75T; It has a 5° climbing ability.

[0010] Further, the longitudinal row car's row car frame is fixed at the rib plate of the cabin bottom, and the longitudinal row car's row car frame is also connected with the rib plate of the cabin longitudinal wall through the transverse support frame.

[0011] Further, the longitudinal row car's beam is provided with a limit sensor and a limit plate.

[0012] Further, during the process of removing the old main engine and hoisting the new main engine, the ship body is kept balanced by adjusting the ballast water, and the forward and backward inclination angle of the ship is controlled to be not more than 5°.

[0013] Further, in the process of removing the old main engine in step (6), the old main engine is disassembled into four parts of the bedplate, the crankshaft, the frame box and the top structure.

[0014] In order to safely and efficiently complete the main engine replacement project, the traditional main engine replacement is broken in the dual-fuel modification, and in the floating state of the ship, according to the parameters of the actual ship environment, the main engine size and tonnage, etc., the space in the cabin is limitedly utilized, a temporary large-tonnage row car is designed and installed by opening a temporary process hole in the front wall of the cabin, and the in-out operation of the new and old main engines is completed by using the double-table 120T row car of the longitudinal row car, so that the replacement of the main engine is completed, and the modification scheme is optimized.

[0015] The main engine replacement method has the advantages of low cost, short period, safe and reliable process, no original system disassembly risk and few additional projects. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a schematic diagram of the main engine in-out passage of the "Messenkai" ship main engine replacement embodiment.

[0017] Figure 2 It is a schematic diagram of the hole opening in the front wall of the cabin in the "Messenkai" ship main engine replacement embodiment.

[0018] Figure 3 It is a schematic diagram of the longitudinal row car frame fastening support structure in the "Messenkai" ship main engine replacement embodiment.

[0019] Figure 4 It is a schematic diagram of the longitudinal row car finite element analysis in the "Messenkai" ship main engine replacement embodiment.

[0020] Figure 5 It is a schematic diagram of the hole opening in the front wall of the cabin in the "Messenkai" ship main engine replacement embodiment.

[0021] Figure 6 It is a schematic diagram of the process of disassembling and removing the old main engine from the cabin in the "Messenkai" ship main engine replacement embodiment.

[0022] REFERENCE SIGNS: 1 - old main engine, 2 - engine room, 3 - engine room front wall plate, 4 - cargo hold, 5 - longitudinal travelling crane, 6 - travelling crane frame, 7 - transverse travelling crane, 8 - process hole. DETAILED DESCRIPTION

[0023] The application will be further described below in conjunction with the drawings and specific examples, but the scope of protection of the application is not limited thereto.

[0024] The ship main engine replacement method of the application will be specifically described by taking the LNG dual-fuel retrofitting of the "Messen Kai" container ship of the American Messen Ship Company as an example. The ship has a length of 217 meters, a type width of 32.2 meters, a type depth of 19.4 meters, a draft of 11 meters, a weight of 29400 tons, and a total of 2600 containers. In the retrofitting project, the shipyard is responsible for the LNG dual-fuel retrofitting design work and completes the main engine and the corresponding system modification and installation.

[0025] (1) Measuring the old main engine top clearance data on the actual ship: first, the old main engine top clearance data is measured on the actual ship, the original ship engine room is 3D scanned, the new main engine is lofted, the new main engine top clearance data is confirmed, the engine room front wall middle area is surveyed on the actual ship, this area has few pipeline units and less disassembly and assembly engineering. The conditions of hoisting space and access are comprehensively confirmed, the first process hole is opened in the engine room front wall, the area where the engine room front wall is located and the cargo hold are used as the access area of the main engine into and out of the engine room, the second process hole is opened in the deck on the top of the cargo hold as the access of the main engine into and out of the cargo hold, as shown in Figure 1 . The main engine into and out of the cargo hold is transported by the longitudinal travelling crane arranged on the center axis of the engine room and the cargo hold, which is used for the main engine into and out of the engine room, and the transverse travelling crane arranged on the deck, which is used for the main engine into and out of the mother ship, as shown in Figure 2 .

[0026] (2) Determine the new main engine factory scheme: the main engine replacement method of the application is the extreme utilization of the ship cabin space. The safe and efficient entry of the main engine parts into the cabin is the key. Before the main engine replacement, the new main engine factory scheme needs to be determined with the ship owner and the main engine manufacturer. The main engine is divided into four parts: the frame, the crankshaft, the frame box and the top structure, which are shipped to the shipyard by ship. The new main engine factory scheme and the weight of the four parts are shown in Table 1.

[0027] Table 1 New main engine factory scheme and weight of four parts Component name Old host component weight New host component weight Bedplate 148t 93t Crankshaft 165t 165t Frame box 208t 116t Top structure 286t 141t (3) Longitudinal crane design: the double-fuel main engine components have the characteristics of large size and heavy tonnage; at the same time, the original ship engine room is distributed with various pipeline and circuit units, and the limitation of engine room space has great operational limitations on the implementation of the main engine replacement project. According to the survey of the actual ship, there is a 4-meter clear space on the top of the engine room equipment. Combined with the premise of the small space and limited hoisting space of the engine room, according to the tonnage and size of the four main components of the engine, a longitudinal crane with large tonnage and small size is designed according to the space, including the size, bearing capacity and fastening installation method of the longitudinal crane. The special design of the crane needs to consider the tonnage of the new and old engine components, the lifting point setting of the engine components, the minimum height requirement of lifting, the distance of transportation and other parameters.

[0028] The longitudinal crane finally determines to adopt two 120T cranes, and the design technical parameter requirements of the crane are as follows: ① The lifting height of the hook needs to reach more than 17.4m from the baseline; ② Two cranes are adopted, and each crane has two independently movable main hooks, and the lifting tonnage of the main hook is more than 60T; the lifting tonnage of the double-hook of a single crane is 120T; ③ In the case that the old main engine components cannot be disassembled, the lifting tonnage of the main hook needs to be increased to 75T; ④ Considering the horizontal state of the ship under the floating state, the crane is required to have a climbing ability of 5°.

[0029] At the same time, the crane walking stop and limit switch are arranged on the walking beam of the crane.

[0030] In order to facilitate the safe walking of the crane between the engine room and the cargo hold, the stability of the crane frame and the beam needs to be fully evaluated. In the present application, the crane frame of the longitudinal crane is fixed at the rib plate at the bottom of the cabin, and the crane frame of the longitudinal crane is also connected with the rib plate at the longitudinal wall of the cabin through the transverse support frame, so as to improve the stability and reliability of the crane frame of the longitudinal crane, as shown in Figure 3 According to the design of the walking beam, the database model is established by using finite element analysis, the walking process of the crane is simulated, the structural strength is calculated by the finite element analysis of the beam strength, so as to confirm the stability and reliability of the crane beam, as shown in Figure 4 At the same time, the safety and reliability of the ship structure are confirmed by mechanical transmission calculation.

[0031] (4) Opening process holes and removing internal components of main engine transportation channel: according to the design of the main engine access channel, the channel needs to be free of any obstruction during the transportation of the main engine components. The crane walks between the engine room and the cargo hold, and due to the structural characteristics of the ship, there is an integral bulkhead plate at the front end of the engine room. A first process hole is opened through the front wall plate of the engine room, as shown in Figure 5The first process hole needs to comprehensively consider the size and tonnage of the new and old main engine, the size of the special crane, the equipment, pipelines, supports, etc. of the front wall of the engine room. At the same time, the pipelines, cables, supports, etc. on the reverse top of the engine room deck are removed to reduce the height of the deck reverse top and prepare for the installation of the crane. The second process hole is started on the deck at the top of the cargo hold of the ship, and the related equipment, pipelines, fittings, etc. in the main engine barge transportation channel need to be removed. The newly added equipment, pipelines, circuits, supports, fittings, etc. of the engine room are not installed before the new main engine is installed in place to avoid affecting the barge transportation channel.

[0032] (5) Install longitudinal and transverse cranes: install the longitudinal crane along the front and rear center axis of the ship and symmetrically on the channel of the cargo hold and the engine room of the ship, and install the transverse crane and hoisting equipment on the deck at the second process hole.

[0033] (7) Remove the old main engine: after removing the pipelines and circuits connected to the old main engine, the old main engine is disassembled in the engine room and is hoisted out of the engine room in batches through the longitudinal crane, enters the cargo hold through the first process hole, and is hoisted out of the hold through the transverse crane, as shown in Figure 6

[0034] The tonnage of the old main engine parts is much larger than that of the new main engine. In order to achieve safety and economy in engineering construction, the old main engine parts are disassembled in the engine room according to the lifting capacity of the crane, and are taken out of the cabin in 8 batches, with the single lifting tonnage controlled within 150T, and the double 120T crane is used for joint lifting.

[0035] (8) Hoist the new main engine: according to the shipyard state of step (2), the new main engine is hoisted into the engine room in batches through the transverse crane and the longitudinal crane, and is assembled; (9) After the assembly of the new main engine is completed, the newly added equipment, pipelines, circuits, supports, fittings related to the new main engine are installed in the engine room, and the first process hole and the second process hole are repaired.

[0036] The inclination of the bow of the ship will cause the climbing angle of the crane, causing difficulty in movement. During the above operation process, the ballast scheme of the ship is adjusted, and the ballast water is adjusted to ensure that the main engine parts enter and exit the engine room as much as possible, so that the inclination angle of the bow of the ship does not exceed 5°.

[0037] The advantages of the main engine replacement method described in the present application compared with the top cabin entry scheme and the slide entry scheme are shown in Table 2. It has the advantages of low cost, short cycle, safe and reliable process, no risk of disassembly of the original system, and less additional engineering.

[0038] Table 2 Comparison table of effects of three schemes Top cabin entry scheme Slide cabin entry scheme The present invention Cost High Low Low Safety quality Original system disassembly and debugging risk Construction safety risk Process safety is reliable; there is no original system disassembly risk Replacement cycle Cycle is very long Cycle is relatively long Cycle is short Incidental engineering Auxiliary machine cabin and other limited modification engineering Only the main engine cabin can be completed Multiple functions, auxiliary shafting, machine cabin structure and other modifications Industry effect Low Low The first scheme provides valuable experience ​The above embodiments are preferred embodiments of the present application, but the present application is not limited to the above embodiments, and any obvious improvement, replacement or modification made by those skilled in the art without departing from the spirit of the present application shall fall within the protection scope of the present application.

Claims

1. A method of replacing a marine main engine, characterized by, The method comprises the following steps: (1) measuring the old main engine top clearance data: through 3D scanning of the original ship engine room, lofting the new main engine, confirming the new main engine top clearance data, and ensuring that the space meets the space requirement of the main engine entering and leaving the engine room as a barge transportation channel at the front wall of the engine room; (2) determining the new main engine delivery scheme: intervening in the supply stage of the main engine components in advance, and confirming the disassembled and shipped state of the new main engine with the ship owner and the main engine manufacturer; (3) longitudinal crane design: according to the disassembly scheme, lifting point setting, size, weight, minimum lifting height, barge transportation distance of the old and new main engines, and the space of the ship engine room, the size, bearing capacity, fastening and installation method of the longitudinal crane are designed; (4) opening process holes, removing internal parts of the main engine barge transportation channel: according to the size and tonnage of the new and old main engines, the size of the longitudinal crane, and the equipment, pipelines and supports at the front wall of the engine room, a first process hole is opened at the front wall of the engine room, and a second process hole is opened on the deck at the top of the ship cargo hold; the pipelines, cables and supports on the deck counter top are removed, the deck counter top height is lowered, the equipment, pipelines and fittings in the main engine barge transportation channel are removed, and the longitudinal crane is installed; (5) installing longitudinal and transverse cranes: the longitudinal crane is installed along the front and rear center axis of the ship and symmetrically on the channel of the ship cargo hold and engine room, and the transverse crane and hoisting equipment are installed on the deck at the second process hole; (6) removing the old main engine: after removing the pipelines and circuits connected to the old main engine, the old main engine is disassembled in the engine room and hoisted out of the engine room in batches through the longitudinal crane, enters the cargo hold through the first process hole, and is hoisted out of the hold through the transverse crane; (7) hoisting the new main engine: the new main engine is hoisted to the engine room in batches through the transverse crane and the longitudinal crane according to the shipyard state of step (2), and is assembled; (8) after the new main engine is assembled, the new equipment, pipelines, circuits, supports and fittings related to the new main engine are installed in the engine room, and the first and second process holes are repaired.

2. The marine engine replacement method according to claim 1, characterized by, The new main engine is a dual-fuel main engine, and in step (2), the determined new main engine delivery scheme is to deliver the main engine into four parts of the main frame, the crankshaft, the frame box and the top structure to the shipyard.

3. The marine engine replacement method according to claim 1, characterized by, In the process of step (3) longitudinal crane design, finite element analysis is used to establish a database model, simulate the crane walking process, and confirm the stability and reliability of the crane girder by calculating the structural strength through finite element analysis of the girder strength; at the same time, the safety and reliability of the ship structure are confirmed through mechanical transmission calculation.

4. The marine engine replacement method according to claim 1, characterized by, In step (3) longitudinal crane design, the following technical requirements are met: The lifting height of the hook reaches more than 17.4m from the baseline; It has 2 independently movable main hooks, and the lifting tonnage of the main hook is more than 60T; the lifting tonnage of the double-hook combined lifting of a single crane is 120T; if the old main engine parts cannot be disassembled, the lifting tonnage of the main hook needs to be increased to 75T; It has a 5° climbing ability.

5. The marine engine replacement method according to claim 1, characterized by, The longitudinal crane frame is fixed at the rib plate at the bottom of the cabin, and the longitudinal crane frame is also connected with the rib plate at the longitudinal wall of the cabin through the transverse support frame.

6. The marine engine replacement method according to claim 1, wherein, The longitudinal crane girder is provided with a limit switch and a limit plate.

7. The marine engine replacement method according to claim 1, wherein, During the process of old engine dismounting and new engine hoisting, the ship is kept balance by adjusting ballast water, and the fore-and-aft inclination angle is controlled not to exceed 5°.

8. The marine engine replacement method according to claim 1, characterized by, During the process of old engine dismounting in step (6), the old engine is dismounted into four parts, i.e. the engine bed, the crankshaft, the frame box and the top structure.

Images