JP2024080852A - Dry ice transport ship - Google Patents

Abstract

[Problem] To provide a dry ice transport ship having a structure suitable for transporting dry ice. [Solution] The ship is equipped with a tank (7) provided in a cargo hold (3), the tank (7) having an opening (9) that can be opened to the upper deck of the ship's hull and a main body (8), and the main body (8) is provided with a bend structure (16). [Selected Figure] Figure 2

Description

The present invention relates to a dry ice transport ship.

In recent years, attention has been focused on the adverse effects of large-scale carbon dioxide (CO2) emissions on the global environment, and efforts to capture and store CO2, or CCUS (Carbon dioxide Capture Utilization and Storage), are gaining momentum.

When there are no suitable CO2 reservoirs near the CO2 emission source, or when there are reservoirs that do not have sufficient storage potential, the CO2 will be transported by pipeline or ship. Pipelines are considered advantageous for short-distance transport, while ship transport is advantageous for long-distance transport. For ship transport, liquefied CO2 carriers that transport CO2 in a liquefied state are considered the most promising.

However, while liquefied CO2 transport ships have been built and operated in Europe and Japan up until now, these existing ships are all small for food use and are unsuitable for CCUS, which requires large-scale transportation.

In addition, CO2 does not liquefy simply by being cooled; pressure is required to liquefy it, so a pressure tank is essential to keep it in a liquefied state. However, due to the structure of the pressure tank, the plate thickness must be increased to increase the pressure and volume. However, since there is a limit to how much the plate thickness can be increased, there is naturally a limit to how large the tank volume can be, i.e., how large the tank can be.

Therefore, it is possible to transport CO2 in a solid state, i.e., in the form of solid carbon dioxide (dry ice). Dry ice is the trade name for solid carbon dioxide. It is also called solid carbonic acid or solid carbonate. Based on its shape, dry ice can be classified into powdered "snow," small granular "pellets," and chunky "blocks." The present invention is not limited to these shape classifications. It is sufficient if the shape is suitable for loading and unloading onto a ship.

As an example of prior art that can be applied to dry ice transport ships, natural gas hydrate transport ships are known (see Patent Documents 1 to 3 below).

Natural gas hydrate is a substance made up of water molecules and natural gas molecules, and is a clathrate hydrate in which natural gas molecules are trapped inside the three-dimensional network structure formed by the water molecules. In particular, artificially produced natural gas hydrate is called "NGH: Natural Gas Hydrate" to distinguish it from "methane hydrate," which exists as a natural resource on the seabed.

Clathrate hydrates are not limited to natural gas hydrates. For example, CO2 hydrate, in which CO2 molecules are trapped inside the three-dimensional network structure formed by water molecules, is also a clathrate hydrate. CO2 hydrate has the advantage that it can be stored at atmospheric pressure, just like dry ice, so there are almost no restrictions on the thickness or volume of the tank. However, the amount of gas per unit volume is small (some research results suggest it is 0.282 g/cm3), and its transport efficiency is significantly inferior to that of dry ice, which has a density of 1.57 g/cm3 at -80°C.

JP 2005-029163 A JP 2005-255075 A JP 2013-010412 A

However, when applying the prior art described in the above Patent Documents 1 to 3, the temperature of natural gas hydrate is -20°C, while the temperature of dry ice is much lower, at -78.5°C (sublimation temperature), so there is a problem that the cargo hold structure of a natural gas hydrate transport ship cannot be applied directly to a dry ice transport ship. This is because the thermal contraction of structural materials such as walls and floors is greater than that of natural gas hydrate.

Therefore, the present invention aims to provide a dry ice transport ship with a structure suitable for transporting dry ice.

The dry ice transport ship of the present invention is characterized in that it has a tank installed in a cargo hold, the tank has an opening that can be opened to the upper deck of the hull, a main body, and a bend structure part installed in the main body.

The present invention provides a dry ice transport ship with a structure suitable for transporting dry ice.

1 is a conceptual overall external view of a dry ice transport ship 1. FIG. 2 is a cross-sectional view (cross-section AA in FIG. 1) of the dry ice transport ship 1 and an enlarged view of a main part. 1 is a conceptual diagram of an anchor portion 14, a key portion 15 and a bend structure portion 16. FIG. This is a diagram showing Table N6.3 of Part N of the Rules for Steel Ships / Liquefied Gas Bulk Carriers. FIG. 1 is a conceptual diagram showing an example of dry ice filling. FIG. 1 is a conceptual diagram showing an example of dry ice dispensing.

Hereinafter, an embodiment of a dry ice transport ship according to the present invention will be described with reference to the drawings.
Fig. 1 is a conceptual overall external view of a dry ice transport ship 1. The dry ice transport ship 1 has a cargo hold 3 in its hull 2. In the figure, three cargo holds 3 are provided, but this is merely one example. The number of cargo holds 3 may be one, two, or four or more.

FIG. 2(a) is a cross-sectional view of the dry ice transport ship 1 (cross-sectional view taken along line AA in FIG. 1), and FIG. 2(b) is an enlarged view of a main portion of the same cross-section (part A in FIG. 2(a)).
As shown in FIG. 2( a ), the cargo hold 3 is configured by providing a tank 7 in a space surrounded by a hull upper deck 4 (hereinafter simply referred to as the upper deck 4 ), a hull outer plating 5 , and an inner wall 6 .

Furthermore, the tank 7 has a main body 8 and an opening 9, and the opening 9 of the tank 7 can be opened to the upper deck 4. Specifically, in the illustrated example, the opening 9 can be opened to the upper deck 4 by removing the cover 10 that covers the opening 9 in a sealed state, and in this open state, dry ice can be filled into the tank 7 and removed from the tank 7. Specific examples of filling and removing will be described later.

As shown in Figure 2 (b), an elastic member 11 such as rubber is interposed between the opening 9 of the tank 7 and the upper deck 4. This elastic member 11 ensures that the tank 7 is airtight while ensuring the connection between the upper deck 4 and the tank 7, and also allows the tank 7 to have the freedom to adapt even if the tank 7 undergoes thermal contraction and expansion, causing the positional relationship between the opening 9 and the upper deck 4 to change.
Both ends of the elastic member 11 are attached to the opening 9 of the tank 7 and the upper deck 4 by restraining devices 11a, 11b such as bolts.

In addition, the cover part 10 and the opening 9 of the tank 7 are not in direct contact with each other, but for example, a hatch coaming 12 of a predetermined height H is interposed between the edge of the cover part 10 and the upper deck 4. This hatch coaming 12 prevents contact between the cover part 10 and the opening 9 of the tank 7, while ensuring and maintaining the airtight state of the tank 7 when the opening 9 of the tank 7 is closed with the cover part 10.

A heat insulating material 13 is attached to the outside (outer surface side) of the main body 8 of the tank 7. In addition, a number of anchor parts 14 are attached to the outside of the main body 8, and a key part 15 is attached to the outside bottom part of the main body 8. For the heat insulating material 13, for example, a method can be used in which polyurethane foam is used as the main heat insulating material, and waterproof plywood or stainless steel plate is attached as the finishing heat insulating material.

Figure 3(a) is a conceptual diagram of the anchor part 14. The anchor part 14 is composed of a hull side part 14a and a paired tank side part 14b, and has the flexibility to follow any displacement of the positional relationship between the main body part 8 of the tank 7 and the inner wall 6 due to thermal contraction and expansion of the tank 7, while absorbing the displacement of the main body part 8 of the tank 7 caused by the rocking of the hull 2 through collision between the hull side part 14a and the tank side part 14b.

Figure 3(b) is a conceptual diagram of the key section 15. The key section 15 also consists of a hull side section 15a and multiple tank side sections 15b (for convenience of illustration, the drawing shows two, left and right or front and rear) arranged to sandwich the hull side section 15a, and prevents the main body section 8 of the tank 7 from rocking forward, backward, left and right when the hull 2 rocks.

In addition, the main body 8 of the tank 7 has a bent structure that is curved almost entirely.
3(c) is a conceptual diagram of the bend structure 16. In this figure, the portion surrounded by a dashed line is the bend structure 16, which is essentially a portion formed with a curve (bend) with as few corners as possible. The displacement of the vent structure 16 relieves stress concentration caused by thermal contraction of the main body 8 of the tank 7.

The materials for the parts to be kept cold (mainly the tanks 7, but also the parts that come into direct contact with the dry ice, such as the cover parts 10, elastic members 11, and hatch coamings 12, as well as the hull and other parts that may affect the cold keeping of the dry ice even if they do not come into direct contact with the dry ice) are selected in accordance with Table N6.3 of the Rules for Steel Ships, Part N, Liquefied Gas Bulk Carriers, in order to withstand the temperature of dry ice (-78.5°C).

Figure 4 shows Table N6.3 of Part N of the Rules for Steel Ships, Liquefied Gas Bulk Carriers. As shown in this figure, materials suitable for the temperature of dry ice (-78.5°C) are preferably those shown in the column for minimum design temperature of -90°C.

Next, a specific example of loading and dispensing dry ice will be described.
Fig. 5 is a conceptual diagram showing an example of dry ice filling. In this diagram, a filling facility 18 equipped with a land conveyor 17 at the top is provided at the port facility, and dry ice is transported by this land conveyor 17 from a dry ice storage facility (not shown).

A transport mechanism 23 consisting of, for example, a first conveyor 19, a second conveyor 20, a chute 21, and a third conveyor 22 is provided downstream of the land conveyor 17, and this transport mechanism 23 enables the dry ice carried by the land conveyor 17 to be transported to the cargo hold 3 of the dry ice transport ship 1 and filled into the tanks 7.

Figure 6 is a conceptual diagram showing an example of dry ice delivery. In this diagram, a pair of parallel guide rails 24 are installed on the upper deck 4 of the dry ice transport ship 1, extending in the fore-and-aft direction of the ship. Furthermore, a gantry 25 is suspended across the pair of guide rails 24 in the ship's width direction, and this gantry 25 can move on the pair of guide rails 24 to position itself above all of the cargo holds 3.

A packet elevator 26 is attached to the gantry 25. This packet elevator 26 can be transformed into a first state in which it is roughly parallel and horizontal to the guide rails 24, and a second state in which it is inserted into the cargo hold 3. It is usually in the first state, but can be transformed into the second state when the dry ice is dispensed.

A gantry conveyor 27 is attached to the gantry 25, and an unloading conveyor 28 is provided along one or both of the pair of guide rails 24, and a shuttle conveyor 29 is provided adjacent to the end of the unloading conveyor 28 and can be extended outside the dry ice transport ship 1.

The dry ice loaded in any cargo hold 3 is transported in sequence via the packet elevator 26, the gantry conveyor 27, the unloading conveyor 28, and the shuttle conveyor 29, and is then dispensed to an overboard storage facility (not shown).

The dry ice transport ship 1 of this embodiment can provide the following effects.
(1) Since substantially the entire body 8 of the tank 7 has a bent structure, stress concentration due to thermal contraction of the body 8 of the tank 7 can be alleviated.
(2) Since an elastic material 11 such as rubber is interposed between the tank 7 and the upper deck 4, the tank 7 can be kept airtight while being given the freedom to follow any thermal contraction or expansion of the tank 7.
(3) The anchor portions 14 are provided on the outside of the tanks 7, so that the displacement of the main body 8 of the tanks 7 caused by the rocking of the hull 2 can be absorbed by the anchor portions 14.
(4) The key portion 15 is provided on the outer bottom of the tank 7, and this key portion 15 can prevent the main body 8 of the tank 7 from rocking back and forth and side to side as the hull 2 rocks.

3 Cargo hold 7 Tank 8 Main body 9 Opening 16 Bend structure

The dry ice transport ship of the present invention is characterized in that it comprises a tank installed in a cargo hold and having an opening that can be opened onto the upper deck of the hull and a main body portion, a cover portion that covers the opening of the tank in an openable and closable manner, an elastic member that is interposed between the tank and the upper deck of the hull and ensures a connection between the upper deck of the hull and the opening of the tank, and a hatch coaming that is interposed between the cover portion and the upper deck of the hull and ensures that the tank is sealed when the opening is closed by the cover portion .

Claims (4)

Equipped with tanks installed in the cargo hold,
The tank has an opening that can be opened to the upper deck of the hull and a main body,
A dry ice transport ship characterized in that a bend structure portion is provided in the main body portion. The dry ice transport ship according to claim 1, further characterized in that an elastic member is interposed between the tank and the upper deck of the ship. The dry ice transport ship described in claim 1 further characterized in that an anchor part is provided on the outside of the tank. 2. The dry ice transport ship according to claim 1, further comprising a key portion provided on the outer bottom of said tank.

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