A design method for adding a methanol fuel tank in the cargo hold area

Abstract

A design method for adding a methanol fuel tank in a cargo hold area, wherein topside tanks are provided on both sides of the top of the hull cargo hold, and ballast tanks are provided on both sides of the bottom of the hull cargo hold. First, a single-hull ship is changed into a double-hull ship, the deck danger zone is divided, the number of internal corrugated bulkheads is calculated, the type of corrugated bulkheads is set, the lower wall pier and the upper wall pier of the corrugated bulkhead are set, the capacity C of the methanol fuel tank and the length of the methanol fuel tank are determined, the front and rear isolation empty tanks are set, and the danger zone is inspected. The present invention divides the methanol tank into multiple tanks, and the tank is a clean tank, which is convenient for washing the cargo hold. After washing, other oil products or chemicals can be loaded, and the dangerous area is inspected. The present invention divides the methanol tank into multiple tanks, and the tank is a clean tank, which is convenient for washing the cargo hold. After washing, other oil products or chemicals can be loaded, and the dangerous area is inspected. The ballast water tank can also be used as an isolation empty tank. When the methanol tank is not used as a methanol tank, the ballast water tank can be used normally. The conventional design method can be expanded to minimize the occupation of the cargo hold capacity while ensuring that the loading capacity of the methanol tank remains unchanged.

Description

Technical Field

[0001] The invention belongs to the field of ship construction and design, and in particular relates to a design method for adding a methanol fuel tank in a cargo hold area. Background Art

[0002] Green methanol is currently attracting much attention in the shipping industry.

[0003] Mass energy density and volume energy density are important indicators for examining the suitability of alternative fuels for shipping, while another important indicator is the storage environment conditions. Methanol fuel can be stored in liquid form at room temperature and pressure, and has good economic efficiency, so it is very popular. At the same time, methanol fuel has the characteristics of low flash point, easy evaporation, low boiling point (64.7℃), and toxicity. Its use as a marine fuel needs to comply with MSC.1 / Circ.1621 and IGF Code. According to the requirements of the regulations, an isolated empty tank should be arranged around the integral methanol fuel tank, and the inorganic zinc silicate coating is used in the methanol tank of the mature product on the market. The special coating process requirements are very strict, and large-sized components should not be arranged in the tank. Therefore, the space for the isolated empty tank around the methanol fuel tank must not only meet the minimum distance required by the regulations, but also consider the space requirements for structural layout. All of the above reasons lead to a larger space required for the layout of the methanol fuel tank, which is about 2.44 compared to the volume ratio coefficient of MGO fuel and about 1.4 compared to the volume ratio coefficient of LNG fuel. Therefore, in order to meet the requirements of greater endurance, the methanol fuel tank is usually arranged in the cargo hold area.

[0004] The problem is:

[0005] (1) There is currently no guidance on how to design methanol tanks.

[0006] (2) For newly designed ships and converted ships, the installation of methanol tanks in the cargo hold area will result in a loss of part of the cargo hold capacity, resulting in a reduction in loading capacity. According to the requirements of the specification, an isolated empty tank should be arranged around the integral methanol fuel tank. The methanol fuel tank is arranged between the engine room and the cargo hold area. Due to the thinning of the stern line and the large deformation, the conventional arrangement scheme (such as Figure 2 There is a lot of waste of space (as shown), and in order to ensure the endurance requirement, it can only expand in the direction of the ship's length, resulting in the distribution of cargo becoming smaller along the length of the ship, the sagging bending moment of the hull beam increases sharply when the cargo is concentrated, the structure is strengthened, and the empty ship weight increases.

[0007] (3) Ships usually have a single tank, which is less flexible and cannot be used in case of leakage.

[0008] (4) Regarding hazardous areas, the interior of the methanol fuel tank is a Class 0 hazardous area, and its diffusion area is a Class 1 hazardous area. Summary of the invention

[0009] To solve the above problems, the present invention provides a design method for adding a methanol fuel tank in the cargo hold area, and the technical solution adopted is as follows:

[0010] A design method for adding a methanol fuel tank in the cargo hold area, with wing tanks provided on both sides at the top of the ship's cargo hold and ballast tanks (4) provided on both sides at the bottom of the ship's cargo hold. The specific steps for establishing the methanol fuel tank are as follows:

[0011] S1: Convert a single-hull ship into a double-hull ship

[0012] Add an inner hull at a distance A from the ship's outer hull to form a side tank, which serves as an isolation empty tank for the methanol fuel tank. A first opening is provided on the bulkhead plate of the wing tank inside the side tank, and a second opening is provided on the bulkhead plate of the ballast tank inside the side tank.

[0013] Isolation empty tanks are provided in front of and behind the methanol fuel tank.

[0014] S2: Division of the deck dangerous area

[0015] An isolation empty tank is provided below the deck in the cargo hold area. The isolation empty tank is located above the methanol fuel tank. The area inside the isolation empty tank is a Class 1 dangerous area, the area inside the methanol fuel tank is a Class 0 dangerous area, the area above the deck in the cargo hold area is a safe area. A PV valve is provided above the methanol fuel tank. The area within a cylinder and sphere with a radius of 6 meters with the PV valve outlet upward is a Class 1 dangerous area, and the area within a cylinder and sphere with a radius of 4 meters outside the Class 1 dangerous area is a Class 2 dangerous area.

[0016] S3: Calculate the number of internal corrugated bulkheads

[0017] The distance between the intersection points of the inner hulls on both sides of the methanol fuel tank and the deck is D. When 0 < D < 20m, the number of longitudinally divided corrugated bulkheads is 0. When 20 < D < 30m, the number of longitudinally divided corrugated bulkheads is 1. When 30 ≤ D < 60m, the number of longitudinally divided corrugated bulkheads is 2.

[0018] One corrugated bulkhead divides the methanol fuel tank into two methanol tanks.

[0019] S4: Set the type of corrugated bulkhead

[0020] The length of the methanol tank is L1. When L1 < 16m, the corrugated bulkhead is set as a horizontal groove. When L1 ≥ 16m, the corrugated bulkhead is set as a vertical groove.

[0021] S5: Set the lower wall pier of the corrugated bulkhead

[0022] The corrugated bulkhead is provided with an upper wall pier and a lower wall pier.

[0023] When there is a vertical groove, the height of the lower wall pier is consistent with the highest point of the internal fold angle of the cabin, and the height does not exceed one-third of the height of the corrugated bulkhead. There is a spacing M between the inclined plate of the lower wall pier and the longitudinal girder at the bottom of the cabin, where 300 < M < 1000 mm, or M is equal to the spacing between the bottom longitudinal stiffeners.

[0024] When there is a horizontal groove, the upper wall pier and the lower wall pier are respectively arranged in the isolation cabins in front of and behind the methanol fuel tank.

[0025] S6: Set the upper wall pier of the corrugated bulkhead

[0026] The height of the upper wall pier is less than that of the lower wall pier, and the height of the upper wall pier is not greater than one-fourth of the height of the corrugated bulkhead.

[0027] S7: Determine the volume C of the methanol fuel tank and the length of the methanol fuel tank

[0028] C = {(mileage / speed / day + reserve) * (methanol consumption of generator / day + methanol consumption of main engine / day) + methanol consumption of boiler} / methanol density * fuel fullness.

[0029] Among them: reserve = methanol consumption for 3 days.

[0030] Methanol density = 0.79 t / m³.

[0031] Fuel fullness = According to the IGF low flash point fuel fullness is 95% - 2% = 93%.

[0032] Length of methanol fuel tank = volume C of the tank / cross-sectional area of the methanol tank.

[0033] S8: Set the front and rear isolation void spaces

[0034] After the volume and length of the methanol fuel tank are determined, isolation void spaces are respectively set at the front bulkhead and the rear bulkhead to separate the methanol fuel tank from the cargo hold through the isolation void spaces;

[0035] S9: Inspect the hazardous area.

[0036] For the above design method of adding a methanol fuel tank in the cargo hold area, further, 600 mm < A < 2000 mm, and the sizes of the first opening and the second opening are 600 * 800 mm.

[0037] For the above design method of adding a methanol fuel tank in the cargo hold area, further, in step S2, the distance between the bottom plate of the isolation void space and the lower surface of the deck is B, and the bottom plate of the isolation void space is parallel to the baseline.

[0038] For the above design method of adding a methanol fuel tank in the cargo hold area, further, in step S2, if the cargo hold area is a Class 0 hazardous area, no isolation void space needs to be set below the deck of the cargo hold area.

[0039] The above-mentioned design method for adding a methanol fuel tank in the cargo hold area, further, in step S3, the number of longitudinally divided bulkheads is not greater than 2.

[0040] The above-mentioned design method of adding a methanol fuel tank in the cargo hold area further provides an isolation space at the bottom of the methanol fuel tank.

[0041] The above-mentioned design method of adding a methanol fuel tank in the cargo hold area further isolates the empty tanks at a distance of 600mm-2000mm.

[0042] The above-mentioned design method of adding a methanol fuel tank in the cargo hold area further comprises a daily cabinet and a fuel storage tank being arranged above the methanol fuel tank, and an isolation air tank being arranged around the daily cabinet and the fuel storage tank.

[0043] The above-mentioned design method of adding a methanol fuel tank in the cargo hold area further has the methanol fuel preparation room being located outside the engine room and being insulated with the Class A machinery space using A-60.

[0044] The above-mentioned design method of adding a methanol fuel tank in the cargo hold area, further, the methanol fuel tank is located below the open deck, and the methanol fuel tank needs to be provided with an independent passage directly leading to the deck.

[0045] The present invention arranges a grooved bulkhead in the cargo hold area to divide the methanol tank into multiple tanks. The interior of the tank is a clean tank (without any components), which is convenient for cleaning the cargo hold. Other oil products or chemicals can be loaded after cleaning, and the tank has strong versatility and flexibility.

[0046] The longitudinal components are kept continuous, and the ballast water tank can also be used as an isolation empty tank. When the methanol tank is not used as a methanol tank, the ballast water tank can be used normally.

[0047] This design method can expand the conventional design method and reduce the cargo hold capacity as much as possible while ensuring that the methanol tank loading capacity remains unchanged.

[0048] Make full use of existing structures, and the design scheme is applicable to modified ships and existing shipbuilding designs, providing design guidance. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a cross-section diagram of a single-hull ship converted into a double-hull ship (vertical groove);

[0050] Figure 2 It is a cross-section diagram of a single-hull ship converted to a double-hull ship (horizontal groove);

[0051] Figure 3 It is a schematic diagram of the division of dangerous areas;

[0052] Figure 4It is a schematic cross-sectional view of a methanol tank installed in the midship of a VLCC

[0053] Figure 5 It is a schematic cross-sectional view of a methanol tank installed in the midship of a container ship

[0054] Among them, 1 - outer hull plate, 2 - inner shell, 3 - wing tank, 4 - ballast tank, 5 - first opening, 6 - lower bulkhead pier, 7 - upper bulkhead pier, 8 - second opening. Specific implementation method

[0055] The present invention will be further described in conjunction with the accompanying drawings.

[0056] As Figure 1 、 2 shown, a design method for adding a methanol fuel tank in the cargo hold area. Wing tanks 3 are provided on both sides at the top of the hull cargo hold, and ballast tanks 4 are provided on both sides at the bottom of the hull cargo hold. The specific steps for establishing the methanol fuel tank are as follows:

[0057] S1: Convert a single-hull ship into a double-hull ship

[0058] A new inner shell 2 is added at a distance of 1A from the outer hull plate to form a side tank. The side tank serves as an isolation empty tank for the methanol fuel tank. A first opening 5 is provided on the bulkhead plate of the wing tank inside the side tank to connect the wing tank 3 and the ballast tank 4. 600mm < A < 2000mm, the first opening is 600 * 800mm, and a second opening 8 is provided on the bulkhead plate of the ballast tank inside the side tank.

[0059] Isolation empty tanks are provided in front of and behind the methanol fuel tank.

[0060] If it is a double-hull ship, directly skip step S1.

[0061] S2: Deck hazard area division

[0062] An isolation empty tank is provided below the deck in the cargo hold area. The isolation empty tank is located above the methanol fuel tank. The inside of the isolation empty tank is a Class 1 hazardous area, the inside of the methanol fuel tank is a Class 0 hazardous area, the area above the deck in the cargo hold area is a safe area. A PV valve is provided above the methanol fuel tank. The area within a cylinder and a sphere with an upward outlet of the PV valve and a radius of 6 meters is a Class 1 hazardous area, and the area within a cylinder and a sphere with an outer radius of 4 meters outside the Class 1 hazardous area is a Class 2 hazardous area.

[0063] For ships where the cargo hold area is not a Class 0 dangerous area, an isolating empty space is usually provided under the deck. That is, an isolating empty space bulkhead is set parallel to the baseline at a distance of B below the deck. In this way, the fuel tank is a Class 0 dangerous area, the isolating compartment is a Class 1 dangerous area, and the deck surface remains a safe area. A PV valve is installed near the upper part of the methanol fuel tank for pressure regulation. The area within a 6-meter radius cylinder and a 6-meter radius sphere above the outlet of the PV valve is a Class 1 dangerous area (R = 6m), and the area within a 4-meter radius cylinder and a 4-meter radius sphere outside the Class 1 dangerous area is a Class 2 dangerous area (R = 4m). If the cargo hold area is a Class 0 dangerous area, there is no need to set up a separate isolating empty space.

[0064] S3: Calculate the number of internal corrugated bulkheads

[0065] The distance between the intersections of the inner hull and the deck on both sides of the methanol fuel tank is D. When 0 < D < 20m, there is no need to set up longitudinal dividing bulkheads, and the number of longitudinally divided corrugated bulkheads is 0. When 20 < D < 30m, the number of longitudinally divided corrugated bulkheads is 1. When 30 ≤ D < 60m, the number of longitudinally divided corrugated bulkheads is 2.

[0066] One corrugated bulkhead divides the methanol fuel tank into two methanol tanks.

[0067] S4: Set the type of corrugated bulkhead

[0068] The length of the methanol tank is L1. When L1 < 16m, the corrugated bulkhead is set as a horizontal groove. When L1 ≥ 16m, the corrugated bulkhead is set as a vertical groove.

[0069] S5: Set the lower wall pier of the corrugated bulkhead

[0070] The corrugated bulkhead is provided with an upper wall pier and a lower wall pier.

[0071] In the case of a vertical groove, the height of the lower wall pier is the same as the highest point of the internal fold angle and does not exceed one-third of the height of the corrugated bulkhead. There is a spacing M between the inclined plate of the lower wall pier and the bottom longitudinal girder, where 300 < M < 1000mm, or M is equal to the spacing of the bottom longitudinal stiffeners.

[0072] In the case of a horizontal groove, the upper wall pier and the lower wall pier are respectively arranged in the isolating compartments in front of and behind the methanol fuel tank.

[0073] S6: Set the upper wall pier of the corrugated bulkhead

[0074] The height of the upper wall pier is less than the height of the lower wall pier, and the height of the upper wall pier does not exceed one-fourth of the height of the corrugated bulkhead. Generally, the height of the upper wall pier 7 is less than the height of the lower wall pier 6 and does not exceed one-fourth of the height of the corrugated bulkhead. The upper wall pier of the horizontal groove is generally arranged in the isolating compartment of the methanol tank and can be set according to the size of the isolating compartment.

[0075] For compartments where the bottom and the side cannot be used as isolating empty spaces, add isolating empty spaces. Such as Figure 2 As shown, for cabins with other functions, it is necessary to add isolated empty compartments. If a cross intersection area appears, it needs to be set at a longitudinal spacing.

[0076] Usually, the methanol fuel tank is arranged in the cargo hold area before the front bulkhead of the engine room and behind the collision bulkhead, and is connected to other cargo holds and away from the safety area. For ease of use, the length of the pipeline between the center of the methanol tank and the engine room area is not more than 100m.

[0077] S7: Determine the capacity C and length of the methanol fuel tank

[0078] C = {(mileage / speed / day + reserve amount)*(generator methanol consumption / day + main engine methanol consumption / day)+boiler methanol consumption} / methanol density*fuel fullness.

[0079] Among them: Reserve quantity = 3 days' methanol consumption.

[0080] Methanol density = 0.79t / m3.

[0081] Fuel fullness = According to IGF low flash point fuel fullness is 95% - 2% = 93%.

[0082] Methanol fuel tank length = tank capacity C / methanol tank cross-sectional area.

[0083] S8: Set up front and rear isolation cabins

[0084] After the capacity and length of the methanol fuel tank are determined, isolated void compartments are set at the front bulkhead and the rear bulkhead respectively, and the methanol fuel tank is separated from the cargo hold by the isolated void compartments.

[0085] The layout of the daily cabinet is the same as that of the fuel storage tank, and isolated empty tanks are arranged around it (excluding the methanol fuel storage tank and the fuel preparation room).

[0086] Layout of the methanol fuel preparation room. The methanol fuel preparation room should be located outside the engine room and be insulated with A-60 between the engine room and other Class A machinery spaces. If the methanol fuel tank is arranged below the open deck, an independent direct access to the deck is required.

[0087] S9: Check the danger zone.

[0088] For ships whose cargo hold areas are not in Category 0 hazardous areas, hazardous area inspections are required, such as Figure 3As shown, the methanol fuel tank is a Class 0 hazardous area; the cofferdam including the top side tank 3, the bottom side tank 4, etc. is a Class 1 hazardous area, and the ballast tanks and the like adjacent to it longitudinally are still safe areas; the upper and lower piers are all Class 1 hazardous areas, and the width of the bottom tunnel 8 is within the boundary of the lower pier tank, ensuring that the bottom tunnel 8 and the methanol fuel tank are neither adjacent nor intersecting. The bottom tunnel is a safe area to ensure that the ballast piping system and the like are not affected by the spread of the hazardous area; the longitudinal cofferdam 9 is a Class 1 hazardous area, and the hazardous area type of the cargo holds adjacent to the front and rear of the methanol fuel tank is not affected by the methanol fuel tank, but is only related to the cargo type; the daily cabinet is a Class 0 hazardous area, and the surrounding cofferdam is a Class 1 hazardous area; the fuel preparation room is a Class 1 hazardous area.

[0089] The present invention can also be used for VLCC conversion ships and container conversion ships (such as Figure 4 , 5 shown).

[0090] Setting a grooved bulkhead in the cargo hold area can divide the methanol tank into multiple tanks. The interior of the tank is a clean tank (without any components), which is convenient for cleaning the cargo hold. Other oil products or chemicals can be loaded after cleaning, which has strong versatility and flexibility.

[0091] The longitudinal components are kept continuous, and the ballast water tank can also be used as an isolation empty tank. When the methanol tank is not used as a methanol tank, the ballast water tank can be used normally.

[0092] This design method can expand the conventional design method and reduce the cargo hold capacity as much as possible while ensuring that the methanol tank loading capacity remains unchanged.

[0093] Make full use of existing structures, and the design scheme is applicable to modified ships and existing shipbuilding designs, providing design guidance.

Claims

1. A design method for adding a methanol fuel tank in a cargo hold area, characterized in that: On both sides of the top of the hull cargo hold, wing tanks (3) are provided, and on both sides of the bottom of the hull cargo hold, ballast tanks (4) are provided. The specific steps for establishing a methanol fuel tank are as follows: S1: Convert a single-hull ship into a double-hull ship An inner hull (2) is newly added at a distance of A from the outer hull plate (1) of the ship to form a side tank, and the side tank serves as an isolation void space for the methanol fuel tank. A first opening (5) is provided on the bulkhead plate of the wing tank inside the side tank, and a second opening (8) is provided on the bulkhead plate of the ballast tank inside the side tank; Isolation void spaces are provided in front of and behind the methanol fuel tank; S2: Division of deck hazardous areas An isolation void space is provided below the deck in the cargo hold area. The isolation void space is located above the methanol fuel tank. The inside of the isolation void space is a Class 1 hazardous area, the inside of the methanol fuel tank is a Class 0 hazardous area, the area above the deck in the cargo hold area is a safe area. A PV valve is provided above the methanol fuel tank. The area within a cylinder and a sphere with an upward outlet of the PV valve and a radius of 6 m is a Class 1 hazardous area, and the area within a cylinder and a sphere with an outer radius of 4 m outside the Class 1 hazardous area is a Class 2 hazardous area; S3: Calculate the number of internal corrugated bulkheads The distance between the intersection points of the inner hulls on both sides of the methanol fuel tank and the deck is D. When 0 < D < 20 m, the number of longitudinally divided corrugated bulkheads is 0. When 20 < D < 30 m, the number of longitudinally divided corrugated bulkheads is 1. When 30 ≤ D < 60 m, the number of longitudinally divided corrugated bulkheads is 2; One corrugated bulkhead divides the methanol fuel tank into two methanol tanks; S4: Set the type of corrugated bulkhead The length of the methanol tank is L1. When L1 < 16 m, the corrugated bulkhead is set as a horizontal groove. When L1 ≥ 16 m, the corrugated bulkhead is set as a vertical groove; S5: Set the lower wall pier of the corrugated bulkhead The corrugated bulkhead is provided with an upper wall pier (7) and a lower wall pier (6), In the case of a vertical groove, the height of the lower wall pier is consistent with the highest point of the internal fold angle in the tank, and the height does not exceed one-third of the height of the corrugated bulkhead; there is a spacing M between the inclined plate of the lower wall pier and the bottom longitudinal girder, 300 < M < 1000 mm, or M is equal to the spacing of the bottom longitudinal stiffeners; In the case of a horizontal groove, the upper wall pier and the lower wall pier are respectively arranged in the isolation compartments in front of and behind the methanol fuel tank; S6: Set the upper wall pier of the corrugated bulkhead The height of the upper wall pier is less than the height of the lower wall pier, and the height of the upper wall pier is not greater than one-fourth of the height of the corrugated bulkhead; S7: Determine the tank capacity C of the methanol fuel tank and the length of the methanol fuel tank C = {(mileage / speed / day + reserve) * (methanol consumption of generator / day + methanol consumption of main engine / day) + methanol consumption of boiler} / methanol density * fuel fullness; Among them: reserve = methanol consumption for 3 days; Methanol density = 0.79 t / m3; Fuel fullness = According to the IGF low flash point fuel fullness is 95% - 2% = 93%; Length of methanol fuel tank = tank capacity C / cross-sectional area of methanol tank; S8: Set the front and rear isolation void spaces After the tank capacity and length of the methanol fuel tank are determined, isolation void spaces are respectively provided at the front bulkhead and the rear bulkhead, and the methanol fuel tank is separated from the cargo hold through the isolation void spaces; S9: Inspect the hazardous areas.

2. The design method for adding a methanol fuel tank in the cargo hold area according to claim 1, characterized in that: 600 mm < A < 2000 mm, and the sizes of the first opening and the second opening are 600 * 800 mm.

3. The design method for adding a methanol fuel tank in a cargo hold area according to claim 1, characterized in that: In step S2, the distance between the bottom plate of the cofferdam and the lower surface of the deck is B, and the bottom plate of the cofferdam is parallel to the baseline.

4. The design method for adding a methanol fuel tank in a cargo hold area according to claim 1, characterized in that: In step S2, if the cargo hold area is a Class 0 hazardous area, there is no need to set up an isolated empty compartment under the deck of the cargo hold area.

5. The design method for adding a methanol fuel tank in a cargo hold area according to claim 1, characterized in that: In step S3, the number of longitudinally divided bulkheads is no more than 2.

6. The design method for adding a methanol fuel tank in a cargo hold area according to claim 1, characterized in that: An isolation chamber is also provided at the bottom of the methanol fuel tank.

7. The design method for adding a methanol fuel tank in a cargo hold area according to claim 1, characterized in that: The spacing between the isolation compartments is 600mm-2000mm.

8. The design method for adding a methanol fuel tank in a cargo hold area according to claim 1, characterized in that: Daily cabinets and fuel storage tanks are arranged above the methanol fuel tank, and isolated air tanks are arranged around the daily cabinets and the fuel storage tanks.

9. The design method for adding a methanol fuel tank in a cargo hold area according to claim 1, characterized in that: The methanol fuel preparation room is located outside the engine room and is insulated with A-60 from the Class A machinery space.

10. The design method for adding a methanol fuel tank in a cargo hold area according to claim 1, characterized in that: The methanol fuel tank is located below the open deck and an independent passage leading directly to the deck must be provided for the methanol fuel tank.

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