A method for expanding the methanol fuel tank of a bulk carrier

Abstract

A method for expanding the methanol fuel tank of a bulk carrier is disclosed. A methanol fuel tank is located between the engine room and the first cargo hold adjacent to the engine room. The top bulkhead of the methanol fuel tank forms the hull deck, and an isolation compartment surrounds the methanol fuel tank. The inner bulkheads of the side ballast tanks on both sides of the hull extend upwards to the deck, serving as isolation compartments on either side of the methanol fuel tank. A common bulkhead connects the side ballast tanks and the methanol fuel tank. The interior of the methanol fuel tank uses a channel-shaped bulkhead, separating at least two fuel tanks. Compared to conventional designs, this eliminates the need for upper and lower bulkheads within the tank, saving significant space. Compared to conventional designs, the methanol tank capacity can be increased by approximately 20% without changing the cargo hold capacity. This effectively reduces the length occupied by the cargo hold area, increases cargo hold capacity, and significantly reduces the impact on the longitudinal bending moment of the hull beams, optimizing the structural design and empty ship weight.

Description

Technical Field

[0001] This invention belongs to the field of shipbuilding and design, and specifically relates to a method for expanding the capacity of methanol fuel tanks on bulk carriers. Background Technology

[0002] With carbon emission restrictions in place, global green methanol production is on the rise. As a marine fuel, methanol can reduce sulfur oxides (SOx) emissions by approximately 99%, nitrogen oxides by 80%, and carbon dioxide emissions by up to 25%. Green methanol has broad development feasibility as a marine fuel globally, with 122 of the world's top 100 ports offering methanol refueling. According to forecasts from relevant organizations, between 2025 and 2050, methanol will compete with low-sulfur fuel oil in terms of price and will play a "significant role" in the global marine fuel mix. Drewry predicts that half of the ships ordered after 2025 will use dual-fuel engines, a large portion of which will choose methanol.

[0003] Methanol fuel can be stored in a liquid state at normal temperature and pressure, making it economically viable and therefore highly favored. Figure 1 As shown, the problem with the arrangement of methanol fuel tanks in current methanol-fueled ship designs lies in:

[0004] (1) Methanol is a low flash point fuel and has a larger volume ratio coefficient than conventional fuels. The required volume of methanol fuel tank is large, and the space in the engine room is limited. If it is placed in the engine room, it cannot meet the range requirements.

[0005] (2) According to the specifications, an isolation compartment should be arranged around the integral methanol fuel tank. The methanol fuel tank should be arranged between the engine room and the cargo hold area. If it is arranged in the middle of the cargo hold, in order to ensure the continuity of the longitudinal components, the installation of the methanol fuel tank will result in serious damage to the cargo hold.

[0006] (3) The methanol fuel tank is located in the middle of the cargo hold area, with no change in the hull shape at the midship section, which is conducive to the layout and has little impact on the overall longitudinal bending moment of the hull beams. However, the fuel tank is far from the end user, and the fuel supply pipeline is longer, which is not the best solution. At the same time, the layout of the day-use cabinets, methanol fuel tank PV valves, etc., has an adverse impact on deck loading and unloading. Summary of the Invention

[0007] To address the aforementioned problems, this invention provides a method for expanding the capacity of methanol fuel tanks on bulk carriers. The aim is to modify and install methanol fuel tanks on conventional bulk carriers, thereby increasing fuel tank capacity and reducing cargo hold capacity loss. The technical solution adopted is as follows:

[0008] A method for expanding the methanol fuel tank of a bulk carrier is provided. The carrier is a conventional bulk carrier. A methanol fuel tank is provided between the engine room and the first cargo hold adjacent to the engine room. The top bulkhead of the methanol fuel tank is the hull deck. An isolation compartment is provided outside the methanol fuel tank to enclose it. The side ballast tank and the methanol fuel tank are connected by a common bulkhead.

[0009] Ballast tanks are provided on both sides of the hull. The inner bulkheads of the ballast tanks extend upward to the deck, adjacent to the methanol fuel tank, serving as isolation compartments on both sides of the methanol fuel tank.

[0010] The methanol fuel tank is equipped with continuous trough-shaped bulkheads that divide the methanol fuel tank into two compartments. The front end of the trough-shaped bulkheads has a front wall block that is reinforced to it, and the rear end of the trough-shaped bulkheads has a rear wall block that is reinforced to it. The front wall block is located between the methanol fuel tank and the front isolation compartment, and the rear wall block is located between the methanol fuel tank and the rear isolation compartment.

[0011] The deck above the methanol fuel tank is equipped with day storage cabinets and a preparation room. The trough-shaped bulkhead eliminates the upper bulkhead at the top and the lower bulkhead at the bottom. The top of the trough-shaped bulkhead extends upward to the deck, and the web of the trough-shaped bulkhead penetrates the deck upward to serve as a common bulkhead for the day storage cabinets and the preparation room.

[0012] The top isolation compartment of the methanol fuel tank is located above the deck, and the day cabinets and preparation room are located inside the top isolation compartment. A row of condenser pipes is suspended inside the methanol fuel tank and on the top bulkhead.

[0013] Furthermore, in the aforementioned method for expanding the methanol fuel tank of a bulk carrier, the methanol fuel tank is located between two side ballast tanks and shares the same inner bulkhead with the side ballast tanks.

[0014] Furthermore, in the aforementioned method for expanding the methanol fuel tank of a bulk carrier, the top isolation compartment is set along the direction above the deck, and the highest point of the top isolation compartment does not exceed 4m.

[0015] Furthermore, in the aforementioned method for expanding the methanol fuel tank of a bulk carrier, the pipe tunnel at the bottom of the methanol fuel tank serves as a bottom-isolated empty compartment.

[0016] Furthermore, in the aforementioned method for expanding the methanol fuel tank of a bulk carrier, the length of the trough-shaped bulkhead along the length of the methanol fuel tank is C2, where 12m≤C2≤19m.

[0017] Furthermore, in the aforementioned method for expanding the methanol fuel tank of a bulk carrier, the bottom end of the trough-shaped bulkhead extends downward and is welded to the bottom bulkhead of the methanol fuel tank.

[0018] In the above methanol fuel tank capacity expansion method based on a bulk carrier, further, the distance between the top cofferdam and the superstructure is not less than 2m.

[0019] In the above methanol fuel tank capacity expansion method based on a bulk carrier, further, a filling station is provided near the methanol fuel tank, and the filling pipeline of the filling station is arranged above the deck and covered and protected by a hatch coaming.

[0020] In the above methanol fuel tank capacity expansion method based on a bulk carrier, further, the preparation room is connected to the main engine through a fuel supply pipeline, and the fuel supply pipeline is located in the top cofferdam.

[0021] In the above methanol fuel tank capacity expansion method based on a bulk carrier, further, the distance from the top of the top cofferdam to the deck is equal to the distance from the top of the top cofferdam to the daily service tank and the preparation room, and the top cofferdam is generally in a convex shape.

[0022] The present invention designs the methanol fuel tank based on the original ship, which can be used for the construction of new ships and also for the modification of existing ships. By modifying the internal structure of the methanol fuel tank and placing the daily service tank and the preparation room above the methanol fuel tank, and arranging a cofferdam outside the daily service tank and the preparation room, the space occupied by the cofferdam is saved and the space utilization rate is increased. The methanol fuel tank, daily service tank and preparation room can share one PV valve, and the PV valve can be arranged nearby at positions such as the top of the fuel tank, which saves the arrangement of two additional PV valves.

[0023] Corrugated bulkheads are adopted inside the methanol fuel tank to divide into at least two fuel tanks. Compared with the conventional design, the upper and lower bilge keels in the cabin are eliminated, which can save a lot of space for the methanol tank. Compared with the conventional design, under the condition that the cargo hold capacity remains unchanged, the capacity of the methanol tank can be increased by about 20%, which effectively reduces the occupied length of the cargo hold area, increases the cargo hold capacity, and greatly reduces the impact on the total longitudinal bending moment of the hull girder at the same time, optimizing the structural design and the lightweight of the empty ship.

[0024] The fuel filling pipeline from the filling station to the fuel tank is arranged on the open deck and under the hatch coaming. The hatch coaming functions to protect the double-wall pipe and prevent possible mechanical damage to the double-wall pipe during cargo loading and unloading. A single-wall pipe can be used for the filling pipeline to reduce the cost. Description of Drawings

[0025] Figure 1 is a structural schematic diagram of a bulk carrier with a methanol fuel tank in the prior art;

[0026] Figure 2 is a structural schematic diagram of the present invention;

[0027] Figure 3 is a top-view structural schematic diagram of the methanol fuel tank of the present invention;

[0028] Figure 4 This is a side view schematic diagram of the bulk carrier structure of the present invention;

[0029] Figure 5 This is a comparison of typical cross-sectional views before and after the expansion of this patent.

[0030] Among them: 1-side ballast tank, 2-pipe tunnel, 3-methanol fuel tank, 4-top side tank, 5-trough-shaped bulkhead, 6-web of the trough-shaped bulkhead, 7-upper bulkhead pier, 8-lower bulkhead pier, 9-day supply cabinet, 10-preparation room, 11-top isolation empty compartment, 12-condenser pipe, 13-ordinary bulkhead, 14-forward bulkhead pier, 15-stern bulkhead pier, 16-refueling station, 17-refueling pipeline, 18-fuel supply pipeline. Detailed Implementation

[0031] The invention will be further described with reference to the accompanying drawings.

[0032] A method for expanding the methanol fuel tank of a bulk carrier involves installing a methanol fuel tank 3 between the engine room and the first cargo hold adjacent to the engine room in a conventional bulk carrier. The top bulkhead of the methanol fuel tank is the ship's deck, and an isolation compartment is provided outside the methanol fuel tank to enclose it. The advantages are that it ensures the longitudinal structural continuity of the entire cargo hold area, with changes only occurring at the last methanol fuel tank, thus guaranteeing structural strength and safety. The methanol fuel tank's location close to the fuel usage terminal in the engine room reduces the need for double-walled fuel supply pipelines, saving pipeline costs.

[0033] The ship has side ballast tanks 1 on both sides of the hull, eliminating the original top side tanks 4 of bulk carriers (such as...). Figure 1 As shown, the inner bulkhead of the side ballast tank extends upwards to the deck, forming a complete side ballast tank from top to bottom. The side ballast tank is adjacent to the methanol fuel tank, which is located between the two side ballast tanks and shares the same inner bulkhead. The side ballast tank serves as an isolation compartment on both sides of the methanol fuel tank. A forward isolation compartment is located at the front of the methanol fuel tank, and a rear isolation compartment is located at the rear.

[0034] The methanol fuel tank is equipped with continuous trough-shaped bulkheads 5, which divide the methanol fuel tank into two compartments, eliminating the need for the original ordinary bulkheads 13 (e.g., Figure 1shown), which ensures safe gas supply, and the adoption of the longitudinal corrugated bulkhead design can increase the utilization rate of the fuel tank and reduce fuel residue. The front end of the corrugated bulkhead plate is provided with a front wall墩 14 reinforced in alignment therewith, and the rear end of the corrugated bulkhead plate is provided with a rear wall墩 15 reinforced in alignment therewith. The front wall墩 is located between the methanol fuel tank and the front isolation compartment, the rear wall墩 is located between the methanol fuel tank and the rear isolation compartment, resulting in zero loss of methanol tank volume. The front wall墩 and the rear wall墩 function to reinforce the corrugated bulkhead plate in alignment, reduce stress concentration, they are arranged between the two bulkheads of the methanol tank isolation compartment, and the inclination angle satisfies 90°<A1<120°. As Figure 3 shown, the length of the corrugated bulkhead plate 5 along the length direction of the methanol fuel tank is C2, and considering the economy of corrugated bulkhead structure design, 12m≤C2≤19m.

[0035] A daily tank 9 and a preparation room 10 are arranged on the deck above the methanol fuel tank. The corrugated bulkhead plate eliminates the upper wall墩 7 at the top end and the lower wall墩 8 at the bottom end. The top end of the corrugated bulkhead plate extends upward to the deck, and the web plate 6 of the corrugated bulkhead plate penetrates the deck upward to form a reinforcing structure aligned with the longitudinal corrugated bulkhead, which serves as a common bulkhead for the daily tank and the preparation room. The bottom end of the corrugated bulkhead plate extends downward and is welded with the bottom bulkhead plate of the methanol fuel tank. By placing the methanol fuel daily tank and the fuel preparation room above the methanol fuel tank, since no isolation is required between the daily tank, the preparation room and the fuel tank, the adjacent arrangement can save isolation space and increase space utilization, only a top isolation compartment needs to be arranged outside the daily tank and the preparation room, which can save the space of the isolation compartment in the tank.

[0036] The top isolation compartment of the methanol fuel tank is located above the deck, the daily tank and the preparation room are located in the top isolation compartment 11. The top isolation compartment is arranged along the extension of the deck, the daily tank and the preparation room, and is overall in a convex shape. The distance from the top isolation compartment to the superstructure is not less than 2m, and the highest point of the top isolation compartment does not exceed 4m. The top isolation compartment can completely enclose the daily tank and the preparation room, the distance between the top of the top isolation compartment and the deck is equal to the distance between the top of the top isolation compartment and the daily tank as well as the preparation piece, which is greater than 1.2m. In order not to block the sight of the superstructure, the height of the part protruding above the deck shall not exceed 4m. This arrangement enables the methanol fuel tank, the daily tank and the preparation room to share one PV valve, and the PV valve can be arranged nearby at positions such as the top of the fuel tank, saving the arrangement of 2 sets of PV valves.

[0037] The pipe tunnel 2 at the bottom of the methanol fuel tank serves as the bottom isolation compartment.

[0038] A row of condensation pipes 12 is suspended on the top bulkhead plate inside the methanol fuel tank, which can be refrigerated through the power supply system. When the volatilized methanol meets the condensation pipes, it becomes liquid and drips back into the tank, ensuring the safety inside the tank.

[0039] As Figure 4As shown, a refueling station 16 is located near the methanol fuel tank. The refueling pipeline 17 of the refueling station is located above the deck and protected by the hatch coaming. The preparation room is connected to the main engine via a fuel supply pipeline 18, which is located in the top isolation compartment. The refueling station (13) should be located as close as possible to the fuel tank and within the midship section of the hull for easy berthing and ship-to-ship refueling. The fuel refueling pipeline (14), from the refueling station to the fuel tank, is located on the open deck and under the hatch coaming. The hatch coaming protects the double-walled pipe from mechanical damage during loading and unloading. This allows the refueling pipeline to use a single-walled pipe instead of a double-walled pipe, reducing costs. The fuel supply pipeline (15), from the fuel preparation room (10) to the main engine, is located in the isolation compartment and uses a double-walled pipe.

[0040] like Figure 5 As shown in the figure, the shaded area represents the increased volume, and the increase in volume per unit length is:

[0041] ΔV=(A+B)*M3+(A+C)*M2+2*C*M1+0.5*(D+E)*F+0.5*(D+M4)*G

[0042] in:

[0043] A represents the vertical distance from the inflection point of the straight section of the isolated empty compartment in the front half of the expanded cabin to the deck.

[0044] B is the height of the deck from the intersection of the inclined section of the expanded front half-cabin isolated empty compartment and the vertical inner shell.

[0045] C represents the height of the straight deck section of the expanded forward half of the cabin from the isolated empty cabin;

[0046] D represents the depth of the trough-shaped bulkhead;

[0047] E is the horizontal distance between the upper bulkhead and the deck addition point before expansion;

[0048] F represents the height of the upper wall pier before expansion;

[0049] G represents the height of the lower wall pier before expansion;

[0050] M1 is the length of the straight deck section before expansion;

[0051] M2 is the horizontal distance between the straight section of the isolated empty compartment and the inclined end point of the deck before expansion;

[0052] M3 is the horizontal distance between the end point of the inclined section of the pre-expansion isolation cabin and the vertical inner shell.

[0053] M4 is the horizontal distance between the lower wall pier and the inner shell before expansion;

[0054] ΔV1=(A+B)*M3 is the increased methanol tank capacity due to the removal of the upper wall pier;

[0055] ΔV2=(A+C)*M2+2*C*M1 is the increased methanol tank capacity due to the removal of the internal isolation compartment;

[0056] ΔV3 = 0.5*(D+E)*F is the increased methanol tank capacity due to the removal of the upper wall pier inside the tank;

[0057] ΔV4=0.5*(D+M4)*G is the increased methanol tank capacity due to the removal of the lower wall pier inside the tank;

[0058] This solution expands the methanol fuel tank, increasing the volume per unit length by approximately 20% compared to conventional designs, thus reducing cargo hold volume loss.

[0059] This invention designs a methanol fuel tank based on the existing ship's design, applicable to both ship construction and retrofitting of existing vessels. The internal structure of the methanol fuel tank is modified by placing the day-use cabinets and preparation room above the fuel tank, with an isolated compartment outside these areas, saving isolation space and increasing space utilization. The methanol fuel tank, day-use cabinets, and preparation room can share a single PV valve, which can be conveniently located near the fuel tank roof, saving the need for two separate PV valve sets.

[0060] The methanol fuel tank utilizes a trough-shaped bulkhead, dividing the space into at least two fuel tanks. Compared to conventional designs, this eliminates the need for upper and lower bulkheads within the ship's hold, saving significant space in the methanol tank. Compared to conventional designs, the methanol tank capacity can be increased by approximately 20% without altering the cargo hold area's capacity. This effectively reduces the length occupied by the cargo hold area, increases cargo hold capacity, and significantly reduces the impact on the overall longitudinal bending moment of the hull beams, optimizing the structural design and the empty ship's weight.

[0061] The fuel refueling pipeline from the refueling station to the fuel tank is arranged on the open deck and under the hatch coaming. The hatch coaming serves to protect the double-walled pipe and prevent mechanical damage that may be caused to the double-walled pipe during loading and unloading. The refueling pipeline can use single-walled pipe to reduce costs.

Claims

1. A method for expanding the methanol fuel tank of a bulk carrier, characterized in that, There are conventional bulk carriers, and a methanol fuel tank (3) is provided between the engine room of the bulk carrier and the first cargo hold adjacent to the engine room. The top bulkhead of the methanol fuel tank is the hull deck, and an isolation compartment is provided outside the methanol fuel tank to enclose the methanol fuel tank. Side ballast tanks (1) are provided on both sides of the hull. The top side tanks (4) on both sides of the hull are eliminated. The inner bulkhead of the side ballast tank is extended upward to the deck and adjacent to the methanol fuel tank, serving as an isolation compartment on the left and right sides of the methanol fuel tank. The side ballast tank and the methanol fuel tank are connected by a common bulkhead. The methanol fuel tank is provided with a continuous trough-shaped bulkhead (5) inside, which divides the methanol fuel tank into two compartments. The front end of the trough-shaped bulkhead has a front wall block (14) that is aligned and reinforced therewith, and the rear end of the trough-shaped bulkhead has a rear wall block (15) that is aligned and reinforced therewith. The front wall block is located between the methanol fuel tank and the front isolation compartment, and the rear wall block is located between the methanol fuel tank and the rear isolation compartment. The methanol fuel tank is equipped with a day cabinet (9) and a preparation room (10) on the deck above it. The trough-shaped bulkhead has the top upper block and bottom lower block eliminated. The top of the trough-shaped bulkhead extends upward to the deck. The web of the trough-shaped bulkhead penetrates the deck upward and serves as the common bulkhead for the day cabinet and the preparation room. The top isolation compartment (11) of the methanol fuel tank is located above the deck, the day cabinet and the preparation room are located in the top isolation compartment, and a row of condenser pipes (12) are suspended inside the methanol fuel tank and on the top bulkhead.

2. The method for expanding the methanol fuel tank of a bulk carrier according to claim 1, characterized in that, The methanol fuel tank is located between the two side ballast tanks and shares the same inner bulkhead with the side ballast tanks.

3. The method for expanding the methanol fuel tank of a bulk carrier according to claim 1, characterized in that, The top isolation compartment is positioned along the direction above the deck, and the highest point of the top isolation compartment does not exceed 4m.

4. The method for expanding the methanol fuel tank of a bulk carrier according to claim 1, characterized in that, The pipe tunnel (2) at the bottom of the methanol fuel tank serves as a bottom isolation chamber.

5. The method for expanding the methanol fuel tank of a bulk carrier according to claim 1, characterized in that, The length of the trough-shaped bulkhead along the length of the methanol fuel tank is C2, where 12m ≤ C2 ≤ 19m.

6. The method for expanding the methanol fuel tank of a bulk carrier according to claim 1, characterized in that, The bottom end of the trough-shaped bulkhead extends downward and is welded to the bottom bulkhead of the methanol fuel tank.

7. The method for expanding the methanol fuel tank of a bulk carrier according to claim 1, characterized in that, The distance between the top isolation cabin and the upper building shall not be less than 2m.

8. The method for expanding the methanol fuel tank of a bulk carrier according to claim 1, characterized in that, A refueling station (16) is located near the methanol fuel tank. The refueling pipeline (17) of the refueling station is located above the deck and is protected by the hatch coaming.

9. A method for expanding the methanol fuel tank of a bulk carrier according to claim 1, characterized in that, The preparation room is connected to the main engine via a fuel supply line (18) located in the top isolation compartment.

10. A method for expanding the methanol fuel tank of a bulk carrier according to claim 1, characterized in that, The distance from the top of the top isolation compartment to the deck is equal to the distance from the top of the top isolation compartment to the day cabinet and the preparation room.

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