KR20140017800A - Unloading system for carbon dioxide carrier - Google Patents

Abstract

Disclosed is an unloading system for a carbon dioxide carrier. The unloading system for a carbon dioxide carrier of the present invention relates to an unloading system of a carrier which liquefies and carries carbon dioxide, including: a plurality of pressurizing tanks prepared on a cargo tank of a hull for storing liquefied carbon dioxide; liquid cargo pipes which are prepared on each pressurizing tanks, and which are connected to the ship deck, from the bottom and through the top of the pressurizing tanks; and an unloading pump which is prepared on the ship deck, and which is connected to the liquid cargo pipes to pump up the carbon dioxide provided by using pressure differences.

Description

Unloading System For Carbon Dioxide Carrier

The present invention relates to an unloading system of a carbon dioxide carrier, and more particularly, a liquid cargo pipe connected to the deck of the hull from the bottom of the pressurized tank to the hull deck in each pressurized tank to be unloaded, A carbon dioxide carrier unloading system capable of controlling the pressure in the tank by returning a portion of gaseous carbon dioxide to the pressurized tank through the return pipe.

Carbon dioxide, released in large quantities as the use of fossil fuels increases, is designated as one of the greenhouse gases causing global warming. Although the global warming index of carbon dioxide is lower than that of other greenhouse gases, it is classified as an important greenhouse gas because it accounts for about 80% of the total greenhouse gas emissions and can regulate emissions. Therefore, various international agreements regulate countries to reduce greenhouse gas emissions to prevent global warming. The Kyoto Protocol, adopted in 1997 and officially entered into force in 2005, is one example. Accordingly, carbon dioxide treatment technology has been proposed to reduce the amount of carbon dioxide, and new business models such as storing carbon dioxide in storage and selling carbon dioxide emission rights sold to other countries are emerging.

Reduction treatment steps for the emission of carbon dioxide are largely carried out through four steps: recovery, separation, concentration, transport and storage of carbon dioxide.

By recovering the exhaust gas including carbon dioxide generated in the industrial site, only carbon dioxide is separated and concentrated at a high concentration. This separation and concentration technique is performed through an absorption process, an adsorption process, or a membrane separation process.

On the other hand, the triple point of the carbon dioxide is known as -56.3 ℃, 0.517 MPa, and the carbon dioxide separated and concentrated through the above process can be stored in a tank in a limited space by cooling and compressing the phase change to a liquid state. The liquefaction of the carbon dioxide can be made by using a variety of known means such as expansion, multistage cooling, mixed cooling method widely used for the liquefaction of natural gas.

In addition, the transport of liquefied carbon dioxide is known to be economical to use a ship rather than a pipe when the transport distance is more than 1000 km. Therefore, ships are suitable as a means of transporting carbon dioxide between countries, and a ship for transporting carbon dioxide should have a tank facility capable of maintaining the liquefied state of carbon dioxide cooled at high pressure and low temperature.

Conventional vessels capable of transporting high-pressure and low-temperature liquefied gas include a ship for transporting compressed natural gas (ExxonMobil, US2005 / 037245). A transport tank for transporting natural gas at about 1.7 MPa, -115 ° C in a liquefied state is presented.

In a similar art, there are LPG carriers that carry pressurized LPG. One type of LPG carrier that is widely used is similar to the condition of a carbon dioxide transport tank because it is equipped with a low temperature, high pressure pressure tank.

In recent years, a cargo ship is often designed and manufactured as a dedicated ship that carries only a specific cargo from the design stage.After transporting a specific cargo from an import source to an import destination, it is collinear when moving from the import destination to the import destination. We need a way to do it. In particular, LNG, LPG carriers or oil shuttle tankers equipped with low-pressure and high-pressure tanks can be used as carbon dioxide carriers under similar conditions to generate profits.

FIG. 1 schematically illustrates a system for unloading a liquid cargo carrier according to an example of the prior art (ExxonMobil No. 10-0569621).

1, the LNG stored in the liquid state is pumped from the tank 16 via the line 20 by an underwater pump 18 when the transport is firmly anchored and the transport line 13 is properly connected, And is transmitted to the booster pump 21. After the booster pump 21 significantly increases the pressure of the LNG, the LNG is delivered to the vaporizer 25 via line 22. The vaporizer 25 vaporizes the LNG and returns it to the natural gas, which is then transported through the transport line 13.

When a plurality of tanks 16 are provided in the liquid cargo carrier S, the submersible pump 18 is provided inside each tank 16.

In such a conventional system, the pipe is installed in a sealed space under the deck, even if the tank 16 and the pipe are welded together, the submersible pump 18 is provided in the lower part of the deck and a valve is provided at the inlet of the pump, so that pipes, in particular, leaks are possible. Since the large valve is disposed under the deck, there may be a problem in that there is a high flammability in case of leakage, and a gas having a low temperature asphyxiation risk is accumulated in the sealed space.

In addition, at the initial stage of unloading, the compressed gas is stored at high pressure in the tank, so the discharge speed is high due to the pressure difference. It slows down and some of the liquid cargo cannot be discharged. This is an important issue related to the transport efficiency of ships.

In particular, when unloading proceeds in a tank storing liquefied carbon dioxide, when the pressure inside the tank falls, it becomes impossible to maintain a liquid state such that the carbon dioxide is solidified and becomes dry ice or evaporated under a pressure condition below the triple point. If the liquid carbon dioxide is solidified, it is also pointed out that dry ice grows in the pipe or tank, which can cause the blockage of the pipe and damage to various equipment.

The present invention is to solve the conventional problems as described above, by providing a liquid cargo pipe connected to the deck of the hull from the bottom of the pressurized tank to the hull deck in each pressurized tank to be unloaded, By returning some of the gaseous carbon dioxide to the pressurized tank through the return piping, it is possible to control the pressure in the tank, preventing the risk of safety accidents that may occur when spilled from the enclosed space, and the pressure in the tank as the unloading proceeds. This is to solve the problem of lowering the discharge rate.

According to an aspect of the present invention, in a cargo ship unloading system for liquefying and transporting carbon dioxide,

A plurality of pressurized tanks provided in a cargo tank of the hull to store the liquefied carbon dioxide;

A liquid cargo pipe provided in the plurality of pressurized tanks and connected to the deck of the hull through an upper part from an inside of the plurality of pressurized tanks; And

The unloading system of the carbon dioxide carrier is provided on the deck and connected to the liquid cargo pipe, including a pump for unloading the pump by receiving the carbon dioxide by the pressure difference.

A loading and unloading system of a carbon dioxide carrier is provided on the deck and connected to the liquid cargo pipe, and includes a liquid header in which the liquefied carbon dioxide is unloaded from the plurality of pressurized tanks, and provided on the deck and the liquid cargo. Further comprising a buffer tank for temporarily storing the carbon dioxide supplied to the unloading pump in the pipe, the liquefied carbon dioxide may be delivered by the pressure difference from the pressurized tank to the unloading pump and the buffer tank. .

The loading and unloading system of the carbon dioxide carrier ship is connected to the return pipe, at least a portion of the carbon dioxide in the gaseous state from the buffer tank to the pressurized tank, a compressor provided in the return pipe and compresses the carbon dioxide, and the return pipe Further comprising a gas header for injecting the carbon dioxide into the pressurized tank, it is possible to control the pressure in the pressurized tank while injecting the carbon dioxide into the pressurized tank.

The unloading system of the carbon dioxide carrier ship includes a liquid pipe for discharging a part of the carbon dioxide in a liquid state from the buffer tank to guide the inlet of the compressor, a liquid pipe pump provided at the liquid pipe to pump the carbon dioxide, and a liquid pipe. A vaporizer may further include a vaporizer provided to vaporize the carbon dioxide pumped from the liquid pipe pump.

The unloading system of the carbon dioxide carrier may further include a liquid cargo piping valve provided at an upper end of the liquid cargo piping and opening and closing the liquid cargo piping, wherein the liquid cargo piping valve may be disposed on the deck.

In the unloading system of the carbon dioxide carrier, the liquid header, the liquid cargo piping valve and the buffer tank may be disposed above the deck, and the unloading pump may be disposed below the deck.

According to another aspect of the present invention, in a cargo ship unloading system for liquefying and transporting carbon dioxide,

The unloading system includes a plurality of pressurized tanks in which liquefied carbon dioxide is stored in the carrier, and one side is provided inside the pressurized tank and the other side is connected to an upper end of the deck to liquefy the pressurized tank. It includes a liquid cargo pipe for releasing the carbon dioxide to lead to the unloading process, the liquid cargo pipe is provided with a carbon dioxide carrier unloading system, characterized in that it does not include a joint at the bottom of the deck.

The pressure in the pressurized tank may be controlled by injecting some of the carbon dioxide discharged from the pressurized tanks through the liquid cargo pipe into the pressurized tanks in a gas state.

According to another aspect of the present invention, there is provided a carbon dioxide carrier equipped with the above-mentioned unloading system of the carbon dioxide carrier.

According to another aspect of the present invention, in the offloading method of the offshore facility for liquefying and transporting carbon dioxide,

The liquefied carbon dioxide is stored in a plurality of pressurized tanks, and the stored carbon dioxide is unloaded through a pump by a pressure difference through a pipe connected in the plurality of pressurized tanks. A suction line is disposed above the deck, and discharges at least a portion of the carbon dioxide transferred to the pump to guide and inject the gas into the plurality of pressurized tanks in a gaseous state to control the pressure in the pressurized tank while unloading the carbon dioxide. There is provided a method for unloading a carbon dioxide carrier.

The unloading system of the carbon dioxide carrier of the present invention is provided with a liquid cargo pipe connected to the deck of the hull from the bottom of the pressurized tank to the deck of the hull in each pressurized tank to be unloaded, the gas state through the return pipe By returning some of the carbon dioxide to the pressurized tank, it is possible to control the pressure in the tank, preventing the risk of a safety accident that may occur when spilled from the enclosed space. You can solve the problem of slowing down.

Figure 1 schematically shows an example of the unloading system of a conventional liquid cargo carrier.
Figure 2 schematically shows the concept of the unloading system of the carbon dioxide carrier in accordance with an embodiment of the present invention.
FIG. 3 schematically illustrates the concept of adding return piping to the system of FIG. 2.
4 schematically illustrates the concept of adding liquid piping to the system of FIG. 3.
Figure 5 schematically shows an embodiment in which the liquid cargo piping valve disposed on the deck in the present invention is provided.
FIG. 6 schematically illustrates an embodiment in which the liquid header, the liquid cargo piping valve and the buffer tank are disposed above the deck and the unloading pump is disposed below the deck in the present invention.

In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the accompanying drawings.

Figure 2 schematically shows the concept of the unloading system of the carbon dioxide carrier in accordance with an embodiment of the present invention.

As illustrated in FIG. 2, the unloading system of a carbon dioxide carrier according to an embodiment of the present invention is a unloading system of a carrier ship for liquefying and transporting carbon dioxide, and the liquefied carbon dioxide stored in a cargo tank of the hull S is stored. The liquid cargo is provided in each of the plurality of pressurized tanks 100 and the plurality of pressurized tanks 100 and connected to the deck (D) of the hull through the upper part from the inside of the plurality of pressurized tanks 100. The pipe 110 and the deck (D) is provided and connected to the liquid cargo pipe 110, and includes a unloading pump 300 for receiving and pumping the carbon dioxide by the pressure difference.

The present embodiment is provided on the deck (D) and connected to the liquid cargo pipe 110, the liquid header 120 and the deck (unloaded) of the liquefied carbon dioxide from the plurality of pressurized tank 100, and the deck ( D) is provided in the liquid cargo pipe 110, and further includes a buffer tank 200 is temporarily stored in the carbon dioxide supplied to the unloading pump 300, the liquefied carbon dioxide for unloading from the pressurized tank 100 It can be delivered by the pressure difference to the pump and the buffer tank.

Pressurized tank 100 is a facility in which the liquid cargo in the tank can be discharged by the pressure difference with the outside of the tank or the buffer tank 200 is set to a high pressure inside the tank. Since the pressurized tank 100 stores high pressure and low temperature liquefied carbon dioxide, the pressurized tank 100 should have durability and heat insulation against such pressure and temperature, and can be equipped with a temperature control facility.

Liquefied carbon dioxide stored in the pressurized tank 100 may be between -55 to -20 ℃, 5.5 to 20 bar, considering the triple point (-56.3 ℃, 0.517 MPa) of carbon dioxide.

In the conventional liquid cargo carrier, the pipes were separated into two types, one for the storage connected to the upper part of the pressurized tank and one for the unloading to the lower part. The unloading pipe connected to the lower part of the pressurized tank is disposed in a sealed space under the deck (D) of the hull, so that it is difficult to detect when an outflow occurs at the connection portion of the tank and the pipe, Hazardous gases may be filled, resulting in suffocation and flammability. However, the present embodiment may be such that the role of these two pipes to be made in one liquid cargo pipe 110.

The liquid cargo pipe 110 of this embodiment is provided in each of the plurality of pressurized tanks 100, and is directed toward the deck D from the bottom of the pressurized tank 100 through the top of the tank. Therefore, even if an outflow occurs in the liquid cargo pipe 110, it stays inside the pressurized tank 100, or can be easily found because it flows out on the deck (D), and the risk of a safety accident is also reduced because it is not an enclosed space.

The liquid cargo pipe 110 and the liquid header 120 may be connected by a flange.

In this embodiment, at least a portion of carbon dioxide in a gaseous state from the buffer tank 200 is returned to the pressurized tank 100, and a compressor 220 provided in the return pipe 210 to compress the carbon dioxide. And a gas header 230 connected to the return pipe 210 to inject carbon dioxide into the pressurized tank 100, while injecting carbon dioxide into the pressurized tank 100, the pressure in the pressurized tank 100. Can be controlled.

The concept of this embodiment is schematically illustrated in FIG. 3.

The liquid header 120 is connected to a plurality of liquid cargo pipes 110 provided in each of the plurality of pressurized tanks 100, thereby collecting liquefied carbon dioxide from each liquid cargo pipe 110 at the time of unloading and then unloading the liquid header 120. Guide to the steps.

As the unloading proceeds, the pressure in the tank drops while liquefied carbon dioxide is discharged in the pressurized tank 100. When the pressure in the tank falls, the pressure difference with the outside is reduced and the discharge rate is slow, this embodiment provided a return pipe 210 to prevent this phenomenon.

By returning a part of the phase change gas carbon dioxide from the carbon dioxide induced in the buffer tank 200 to the pressurized tank 100 to compensate for the reduced pressure of the pressurized tank 100. Pressure reduction in the tank not only affects the rate of discharge, but can also cause a phase change of liquid carbon dioxide. Due to the pressure change in the tank, the solidified carbon dioxide may block the pipe connected to the tank or cause a failure of the equipment such as a pump. The present embodiment can solve the problem by providing the return pipe 210 and the gas header 230. have.

The pressure in the pressurized tank 100 is monitored and the carbon dioxide is compressed in the compressor 220 and injected into the pressurized tank 100 in consideration of the required degree of pressurization. A control unit for the operation of the compressor 220 may be added.

The gas header 230 is provided with a plurality of outlets connected to the plurality of pressurized tanks 100 so that natural gas may be injected into the upper portions of the pressurized tanks 100.

This embodiment is a liquid pipe 240 for discharging a part of the carbon dioxide in the liquid state from the buffer tank 200 to the inlet of the compressor 220, and a liquid pipe pump provided in the liquid pipe 240 to pump carbon dioxide ( And a vaporizer 242 provided in the liquid pipe 240 and vaporizing the carbon dioxide pumped from the liquid pipe pump 241.

The concept of this embodiment is schematically shown in FIG.

When only the carbon dioxide in the gaseous state in the buffer tank 200 cannot achieve the pressurizing effect required for the pressurized tank 100, a portion of the liquefied carbon dioxide induced in the buffer tank 200 is vaporized and introduced into the compressor 220. After that, it may be injected into the pressurized tank 100 along the return pipe 210 and the gas header 230.

Although not shown in the drawing, if necessary, the carbon dioxide may be supplied from the carbon dioxide tank outside the system and injected into the pressurized tank 100 through the compressor 220 to adjust the pressure in the pressurized tank 100.

The embodiment further includes a liquid cargo piping valve 111 provided at the upper end of the liquid cargo piping 110 to open and close the liquid cargo piping 110, the liquid cargo piping valve 111 is the top of the deck (D) Can be placed in.

By extending the liquid cargo piping 110 to the top of the deck (D), and by placing the liquid cargo piping valve 111 on the top of the deck (D), relatively large spills are placed in an open place that is not sealed Safety can be secured. The liquid cargo piping valve 111 may be provided at a portion connecting the liquid cargo piping 110 and the liquid header 120.

The concept of this embodiment is schematically illustrated in FIG.

In another embodiment of the present invention, the liquid header 120, the liquid cargo piping valve 111 and the buffer tank 200 is disposed above the deck (D), the unloading pump 300 of the deck (D) It may be disposed at the bottom.

Another embodiment of this invention is schematically illustrated in FIG. 6. As can be seen in Figure 6, by placing most of the liquid cargo pipe 110, which is likely to leak, on the top of the deck (D) rather than a closed space, even if the leakage can be lowered the risk of safety accidents.

As can be seen in the above embodiments, the unloading pump 300 may be disposed above the deck (D), may be disposed below the deck. However, even when the unloading pump 300 is disposed under the deck (D), the suction line of the pump that is likely to leak is placed on the upper deck (D), so that there may be a case where the discharge from the closed space Prevent safety accidents.

According to another aspect of the present invention, in a cargo ship unloading system for liquefying and transporting carbon dioxide,

The unloading system includes a plurality of pressurized tanks 100 in which liquefied carbon dioxide is stored inside the carrier, and one side is provided inside the pressurized tank 100 and the other side is connected to the upper end of the deck D to pressurize. It includes a liquid cargo pipe 110 to discharge the liquefied carbon dioxide from the type tank 100 to the unloading process, the liquid cargo pipe 110 is characterized in that it does not include a joint at the bottom of the deck (D) An unloading system of a carbon dioxide carrier is provided.

The pressure in the pressurized tank 100 may be controlled by injecting some of the carbon dioxide discharged from the pressurized tank 100 through the liquid cargo pipe 110 into the pressurized tank 100 in a gaseous state. It is characterized by.

According to another aspect of the present invention, there is provided a carbon dioxide carrier equipped with the above-mentioned unloading system of the carbon dioxide carrier.

According to another aspect of the present invention, in the offloading method of the offshore facility for liquefying and transporting carbon dioxide,

The liquefied carbon dioxide is stored in the plurality of pressurized tanks 100, and the stored carbon dioxide is unloaded through a pump by transferring the pressure through a pipe connected in the plurality of pressurized tanks 100, The suction line of the pump is disposed above the deck (D), and discharges at least a portion of the carbon dioxide transported to the pump to guide and inject the plurality of pressurized tanks 100 in a gaseous state to inject pressure in the pressurized tanks 100. There is provided a method for unloading a carbon dioxide carrier, which can unload carbon dioxide while controlling.

As described above, the unloading system of the carbon dioxide carrier of the present embodiment, the pressurized liquid cargo pipe 110 connected to the deck (D) of the hull (S) via the upper portion from the lower portion of the pressurized tank 100, respectively. By providing the tank 100 and unloading, the unloading pipe may be disposed below the tank in the conventional system to reduce the risk of a safety accident that may occur when liquefied carbon dioxide is leaked into the enclosed space. By installing the liquid cargo pipe 110 inside the pressurized tank 100, a heat insulation effect can be obtained without any extra cost around the pipe. Compared with the unloading pipe disposed in the lower part of the conventional tank, the pipe length can be shortened, thereby reducing the installation and maintenance cost of the system.

By providing various pipes and pumps on the upper part of the deck D, it is easy to check and repair the equipment.

In addition, the present embodiment includes a pipe and a gas header 230 to vaporize some of the carbon dioxide gas or liquefied carbon dioxide in the system to lead to the pressurized tank 100, thereby providing the pressurized tank 100 during unloading. As the pressure drop in the pressurized tank 100 rapidly decreases due to a sudden drop in pressure, a problem of blocking a pipe or a valve or damaging the equipment may be solved as the carbon dioxide in the tank is solidified by a phase change, and the pressure of the pressurized tank 100 is maintained. Thus, carbon dioxide in the tank can be discharged quickly without lowering the discharge rate.

Although this embodiment describes liquefied carbon dioxide, the system of this embodiment can be applied to other liquefied gas transportation systems.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Accordingly, such modifications or variations are intended to fall within the scope of the appended claims.

S: hull
D: Deck
100: Pressurized tank
110: liquid cargo piping
111: liquid cargo piping valve
120: liquid header
200: buffer tank
210: return piping
220: compressor
230: gas header
240: liquid piping
241: liquid piping pump
242: carburetor
300: unloading pump

Claims (10)

In the unloading system of a carrier ship liquefying and transporting carbon dioxide,
A plurality of pressurized tanks provided in a cargo tank of the hull to store the liquefied carbon dioxide;
A liquid cargo pipe provided in the plurality of pressurized tanks and connected to the deck of the hull through an upper part from an inside of the plurality of pressurized tanks; And
And a unloading pump connected to the liquid cargo pipe and connected to the liquid cargo pipe to receive and pump the carbon dioxide by a pressure difference. The method of claim 1,
A liquid header provided on the deck and connected to the liquid cargo pipe and unloading the liquefied carbon dioxide from the plurality of pressurized tanks; And
Further comprising a buffer tank provided in the deck and the carbon dioxide is temporarily stored in the liquid cargo pipe supplied to the unloading pump,
The liquefied carbon dioxide is unloaded from the pressurized tank to the unloading pump and the buffer tank by the pressure difference, characterized in that the unloading system of the carbon dioxide carrier. 3. The method of claim 2,
A return pipe leading at least a portion of the carbon dioxide in a gaseous state from the buffer tank to the pressurized tank;
A compressor provided in the return pipe and configured to compress the carbon dioxide; And
A gas header connected to the return pipe to inject the carbon dioxide into the pressurized tank;
And discharging the carbon dioxide into the pressurized tank while controlling the pressure in the pressurized tank. The method of claim 3, wherein
A liquid pipe which discharges a portion of the carbon dioxide in a liquid state from the buffer tank and leads to the inlet of the compressor;
A liquid pipe pump provided in the liquid pipe to pump the carbon dioxide; And
And a vaporizer provided in the liquid pipe and vaporizing the carbon dioxide pumped by the liquid pipe pump. The method of claim 1,
Further provided with an upper end of the liquid cargo pipe and a liquid cargo pipe valve for opening and closing the liquid cargo pipe,
The liquid cargo piping valve is a carbon dioxide carrier ship system, characterized in that disposed on top of the deck. 6. The method of claim 5,
The liquid header, the liquid cargo piping valve and the buffer tank is disposed on top of the deck, the unloading pump is disposed on the lower portion of the deck carbon dioxide carrier unloading system. In the unloading system of a carrier ship liquefying and transporting carbon dioxide,
The unloading system includes a plurality of pressurized tanks in which liquefied carbon dioxide is stored in the carrier, and one side is provided inside the pressurized tank and the other side is connected to an upper end of the deck to liquefy the pressurized tank. And a liquid cargo pipe for discharging the carbon dioxide to be introduced into the unloading process, wherein the liquid cargo pipe does not include a joint at the bottom of the deck. 8. The method of claim 7,
Unloading the carbon dioxide carrier ship, characterized in that the pressure in the pressurized tank can be controlled by injecting some of the carbon dioxide discharged from the pressurized tank through the liquid cargo pipe into the pressurized tank in a gas state. system. A carbon dioxide carrier provided with the unloading system of the carbon dioxide carrier according to any one of claims 1 to 8. In the unloading method of the transport ship which liquefies and transports carbon dioxide,
The liquefied carbon dioxide is stored in a plurality of pressurized tanks, and the stored carbon dioxide is unloaded through a pump by a pressure difference through a pipe connected in the plurality of pressurized tanks. A suction line is disposed above the deck, and discharges at least a portion of the carbon dioxide transferred to the pump to guide and inject the gas into the plurality of pressurized tanks in a gaseous state to control the pressure in the pressurized tank while unloading the carbon dioxide. How to unload a carbon dioxide carrier, characterized in that.

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