KR102690232B1 - Floating marine structure for LNG tank repair - Google Patents

Abstract

A floating offshore structure dedicated to LNG fuel tank maintenance is launched. A floating offshore structure dedicated to LNG fuel tank maintenance according to an embodiment of the present invention includes a structure main body disposed adjacent to a ship requiring maintenance of an LNG fuel tank; An inert gas storage tank that is mounted on the structure body and stores inert gas to replace the LNG gas in the LNG fuel tank with inert gas (unalive gas); And a gas main supply pipe connected to the inert gas storage tank and supplying the inert gas in the inert gas storage tank to the LNG fuel tank.

Description

Floating marine structure for LNG tank repair}

The present invention relates to a floating marine structure dedicated to LNG fuel tank maintenance. More specifically, it is a dedicated facility for maintenance of LNG fuel tanks, so that ships requiring maintenance of LNG fuel tanks can dock ( This is about a floating offshore structure dedicated to LNG fuel tank maintenance that can be used by docking.

Liquefied gas refers to gas made into liquid by cooling or compressing it. In general, when the temperature of a gas is lowered below its critical temperature, it condenses and becomes a liquid, or changes into a state that can become a liquid when compressed (this is called a vapor state), and the gas that becomes liquid in this way is called a liquefied gas.

Liquefied gases include liquefied petroleum gas and liquefied natural gas (LNG). Among these, liquefied natural gas (LNG) is low in price and can be transported by sea, and has low carbon dioxide emissions, so it is considered an energy source for preventing global warming.

Accordingly, demand for production, transportation, and storage facilities (ships) of liquefied natural gas (hereinafter referred to as LNG) is increasing globally. In particular, as environmental issues emerge, the number of ships using LNG as fuel is increasing.

Meanwhile, LNG fuel tanks equipped on ships that use LNG as fuel require periodic maintenance because they handle LNG in a cryogenic state. Here, maintenance may include cleaning work and repair work such as cracking (leak).

To maintain an LNG fuel tank, maintenance devices such as a compressor, heater, and nitrogen generator are required, and these maintenance devices must be installed on the ship.

However, considering that maintenance of LNG fuel tanks is usually performed every 3 to 4 years, as mentioned above, a maintenance device with a large number of devices (or units) and a huge structure is always installed on the ship. Transportation is bound to be inefficient, and considering that existing large LNG ships are equipped with maintenance devices and are bound to be somewhat unreasonable in terms of space utilization, etc., there is a need for technological development to improve this.

Korea Intellectual Property Office Application No. 10-2013-0112209 Korea Intellectual Property Office Application No. 10-2014-0074388

Therefore, the technical problem to be achieved by the present invention is that it is a dedicated facility for maintenance of LNG fuel tanks, so ships requiring maintenance of LNG fuel tanks can dock and use it, and as a result, individual ships can be used as before. The aim is to provide a floating offshore structure dedicated to LNG fuel tank maintenance that eliminates the need to mount a maintenance device, thereby eliminating various losses caused by the installation of a maintenance device.

According to one aspect of the present invention, a structure main body disposed adjacent to a ship requiring maintenance of an LNG fuel tank; An inert gas storage tank mounted on the structure body and storing the inert gas in order to replace the LNG gas in the LNG fuel tank with an inert gas (unalive gas); And a gas main supply pipe connected to the inert gas storage tank and supplying the inert gas in the inert gas storage tank to the LNG fuel tank may be provided.

It is mounted on the structure main body adjacent to the inert gas storage tank and may further include an atmospheric heat exchanger for heating the inert gas.

a gas bypass pipe provided via the atmospheric heat exchanger and both ends of which are connected to different positions of the gas main supply pipe; And it may further include a gas branch pipe provided to branch from the gas main supply pipe and forming a path different from the gas main supply pipe.

It may further include a blower provided in the gas branch pipe.

A first electromagnetic valve provided to be able to be turned on/off in the main gas supply pipe between the inert gas storage tank and the gas bypass pipe; second and third electromagnetic valves that can be turned on/off at both end areas of the gas bypass pipe; a fourth solenoid valve that can be turned on/off in the gas main supply pipe between the gas bypass pipes; A fifth electromagnetic valve provided in the gas branch pipe to be capable of being turned on/off; And the inert gas is liquid nitrogen (LN2), and the liquid nitrogen (LN2) is supplied as is to the LNG fuel tank in a predetermined cool down mode or through the atmospheric heat exchanger. After heating to make gaseous nitrogen, the operation of the first to fifth solenoid valves is selectively turned on/off based on a predetermined warm up mode in which the gaseous nitrogen is supplied to the LNG fuel tank. off) Controllers may be further included.

It may further include a docking arm provided on the structure main body and docked with the ship for connection with a ship approaching the structure main body.

According to the present invention, since it is a dedicated facility for maintenance of LNG fuel tanks, ships requiring maintenance of LNG fuel tanks can dock and use it, and as a result, maintenance devices are installed on individual ships as before. Since there is no need to mount a maintenance device, various losses caused by the mount can be eliminated.

Figure 1 is a diagram showing the use state of a floating offshore structure dedicated to LNG fuel tank maintenance according to the first embodiment of the present invention.
Figure 2 is an enlarged view of the floating offshore structure dedicated to LNG fuel tank maintenance shown in Figure 2.
Figure 3 is a plan view of the structure of Figure 2.
Figure 4 is a control block diagram for the floating offshore structure dedicated to LNG fuel tank maintenance of Figure 1.
Figure 5 is a diagram showing the use state of a floating offshore structure dedicated to LNG fuel tank maintenance according to the second embodiment of the present invention.
Figure 6 is a diagram showing the use state of a floating offshore structure dedicated to LNG fuel tank maintenance according to the third embodiment of the present invention.

In order to fully understand the present invention, its operational advantages, and the objectives achieved by practicing the present invention, reference should be made to the accompanying drawings illustrating preferred embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, the present invention will be described in detail by explaining preferred embodiments of the present invention with reference to the accompanying drawings. The same reference numerals in each drawing indicate the same member.

Figure 1 is a diagram showing the use state of a floating offshore structure dedicated to LNG fuel tank maintenance according to the first embodiment of the present invention, and Figure 2 is an enlarged view of the floating offshore structure dedicated to LNG fuel tank maintenance shown in Figure 2. , FIG. 3 is a plan structural diagram of FIG. 2, and FIG. 4 is a control block diagram of the floating offshore structure dedicated to LNG fuel tank maintenance of FIG. 1.

Referring to these drawings, the floating offshore structure 100 according to this embodiment is a dedicated facility for maintenance of the LNG fuel tank 20 mounted on the ship 10 propelled by LNG.

As shown in FIG. 1, after the ship 10 requiring maintenance of the LNG fuel tank 20 is docked, that is, connected to the floating marine structure 100 according to this embodiment, the LNG of the ship 10 Maintenance for the fuel tank 20 may be performed. Here, maintenance may include cleaning work and repair work such as cracking (leak).

When the floating offshore structure 100 as in this embodiment is applied, the ship 10 requiring maintenance of the LNG fuel tank 20 can dock and use it, so individual ships 10 can be used as before. Since there is no need to install a maintenance device, various losses caused by the installation of a maintenance device can be eliminated.

Here, various losses refer to everything such as space utilization and maintenance due to device aging.

Looking at this in more detail, if there is no need to mount a maintenance device on each individual ship 10 as before, the operating efficiency of the ship 10 can be increased due to weight reduction. Therefore, fuel consumption is reduced.

In addition, since the maintenance device is not mounted on the ship 10, various and complicated pipes for implementing the maintenance device can be simplified, which is very advantageous in securing space on the ship 10 and reducing CAPEX ( Capital expenditures) can be reduced.

As briefly mentioned earlier, it is known that maintenance of the LNG fuel tank 20 in the LNG ship 10 is usually performed every 3 to 4 years. This means that maintenance of the LNG fuel tank 20 only needs to be performed once every 3 to 4 years, but it is quite difficult to always carry a maintenance device to be used once every 3 to 4 years on the ship 10. It is bound to be inefficient.

Therefore, as in the present embodiment, a dedicated floating marine structure 100 for maintenance of the LNG fuel tank 20 is applied, and the ship 10 that requires maintenance of the LNG fuel tank 20 is used in this embodiment. After approaching and docking the floating marine structure 100 of the example, if maintenance of the LNG fuel tank 20 is performed, various problems or losses described above can be eliminated.

For reference, the floating marine structure 100 applied to this embodiment may be a series of facilities or structures (or structures) that are anchored while floating on the sea.

In this case, the ship 10 of FIG. 1, which requires maintenance of the LNG fuel tank 20, moves to and docks with the floating offshore structure 100 applied to this embodiment, and then the main of the LNG fuel tank 20 You can proceed with tinance.

However, the floating offshore structure 100 applied to the present embodiment does not necessarily have to be a series of facilities floating and anchored in the sea, which will be further explained with reference to the drawings in the embodiment below.

Meanwhile, looking at the floating marine structure 100 according to this embodiment in more detail, the floating marine structure 100 according to this embodiment is provided with a structure main body 110, and the structure main body 110 On the top, an inert gas storage tank (120), various pipes (131, 132, 133), an atmospheric heat exchanger (160), a blower (170), etc. are mounted at each location.

The structure main body 110 is the external structure of the floating marine structure 100 according to this embodiment. The form can be freely applied. Accordingly, the scope of the present invention is not limited to the shape of the drawings.

A power device 115 is provided on one side of the structure main body 110. The power device 115 supplies power to devices that require power among components or devices mounted on the structure body 110.

If the floating marine structure 100 according to this embodiment is a normal ship, the power device 115 may be responsible for the power for propulsion of the ship.

The structure main body 110 is placed adjacent to the ship 10 requiring maintenance of the LNG fuel tank 20 as shown in FIG. 1 and then connected. In reality, since inert gas must be supplied during maintenance of the LNG fuel tank 20, the structure main body 110 and the corresponding vessel 10 should not be arbitrarily separated.

Therefore, the ship 10 that requires maintenance of the LNG fuel tank 20 must be docked, that is, connected to the structure main body 110 of the floating offshore structure 100 according to this embodiment. For this, the structure main body A docking arm (180) is provided at (110).

This docking arm 180 is provided on the structure main body 110 and is used as a part for docking the ship 10 to connect with the ship 10 approaching the structure main body 110.

In this embodiment, a plurality of docking arms 180 are applied and have a link-type structure capable of arbitrary rotation as shown in FIG. 2. Therefore, efficient and stable docking with a neighboring vessel 10 is possible.

However, the scope of the present invention is not limited to these matters. In other words, since the docking arm 180 shown in the drawing is only an example, the scope of the present invention is not limited to the number or shape of the docking arm 180 shown in the drawing.

The inert gas storage tank 120 is mounted on the structure main body 110 and forms a place where inert gas is stored to replace the LNG gas in the LNG fuel tank 20 with inert gas.

Inert gas is a general term for gases that are difficult to cause chemical reactions with other substances. It is used to prevent the risk of explosive gases or vapors such as LNG.

In this embodiment, the inert gas is liquid nitrogen (LN2), and this inert gas is supplied into the LNG fuel tank 20 to block air so that combustible gas, steam, and oxygen do not have the opportunity to come into contact and cause a chemical reaction. Turn it off. Therefore, workers can enter the LNG fuel tank 20 and perform various types of maintenance.

For reference, liquid nitrogen (LN2) is liquefied nitrogen and exists as a liquid at -196°C under atmospheric pressure. The critical temperature is -147.21℃ and the critical pressure is 33.5atm. Nitrogen is a two-atomic molecule, a gaseous element that accounts for 80% of the volume of air. Industrially, it can be obtained by fractionation liquefaction of air, and chemically, it can be fractionated by heating a mixture of ammonium chloride and sodium nitrite to 70°C. Obtained by distillation.

An atmospheric heat exchanger 160 is provided around the inert gas storage tank 120. The atmospheric heat exchanger 160 is mounted on the structure main body 110 adjacent to the inert gas storage tank 120, and serves to heat the inert gas to convert it into gaseous nitrogen.

The various pipes 131, 132, and 133 provided in the structure main body 110 may include a gas main supply pipe 131, a gas bypass pipe 132, and a gas branch pipe 133, as shown in detail in FIG. 3.

The gas main supply pipe 131 is connected to the inert gas storage tank 120 and serves to supply the inert gas in the inert gas storage tank 120 to the LNG fuel tank 20.

Although not shown in detail in the drawing, a spray nozzle (not shown) is installed at the end of the gas main supply pipe 131 to supply the inert gas, that is, liquid nitrogen (LN2), in the inert gas storage tank 120 through the gas main supply pipe 131. ) can be provided.

The gas bypass pipe 132 is provided via the atmospheric heat exchanger 160, and both ends are connected to different positions of the gas main supply pipe 131. When the fourth solenoid valve 144 is closed, liquid nitrogen (LN2) is bypassed through the gas bypass pipe 132 and heated to a gaseous state.

The gas branch pipe 133 is provided to branch from the gas main supply pipe 131, but forms a different path from the gas main supply pipe 131.

A blower 170 is provided in this gas branch pipe 133. The blower 170 serves to inject, for example, gaseous nitrogen into the LNG fuel tank 20 through the gas branch pipe 133. That is, when the fourth solenoid valve 144 is closed and the fifth solenoid valve 145 is opened, liquid nitrogen (LN2) can be heated into gaseous nitrogen by the atmospheric heat exchanger 160, and gaseous nitrogen in this state is blown ( 170) can be sprayed.

Meanwhile, a plurality of electromagnetic valves 141 to 145 are provided at each location in these pipes 131, 132, and 133. In addition, the floating marine structure 100 according to this embodiment is equipped with a controller 150 to control a plurality of electromagnetic valves 141 to 145.

The first electromagnetic valve 141 is a valve that can be turned on/off in the gas main supply pipe 131 between the inert gas storage tank 120 and the gas bypass pipe 132. The second and third solenoid valves 142 and 143 are valves that can be turned on/off at both end areas of the gas bypass pipe 132. The fourth solenoid valve 144 is a valve that can be turned on/off in the gas main supply pipe 131 between the gas bypass pipes 132. And, the fifth solenoid valve 145 is a valve 145 provided in the gas branch pipe 133 to be able to turn on/off.

Meanwhile, the controller 150 heats the liquid nitrogen (LN2) in a predetermined cool down mode that supplies the liquid nitrogen (LN2) to the LNG fuel tank 20 as is or through the atmospheric heat exchanger 160. After converting the gaseous nitrogen into gaseous nitrogen, the operation of the first to fifth solenoid valves 141 to 145 is selectively turned on/off based on a predetermined warm up mode to supply the gaseous nitrogen to the LNG fuel tank 20. Control on/off.

Cool down mode uses liquid nitrogen (LN2) in the inert gas storage tank (120) in the LNG fuel tank (20) subject to maintenance or after repairs have been completed without going through the standby heat exchanger (160). This refers to the mode of supplying the desired LNG fuel to the inside of the fuel tank (20).

In addition, the warm up mode is a mode to warm the inside of the LNG fuel tank 20 because the LNG fuel tank 20 subject to maintenance is very cold. In this case, the inert gas storage tank 120 ) refers to a mode in which the liquid nitrogen (LN2) in the tank passes through the atmospheric heat exchanger (160) to become warm gaseous nitrogen, and then this gaseous nitrogen is supplied to the inside of the LNG fuel tank (20).

The controller 150 that performs this role may include a central processing unit (151, CPU), memory (152, MEMORY), and a support circuit (153, SUPPORT CIRCUIT).

In this embodiment, the central processing unit 151 selectively turns on/off the operation of the first to fifth solenoid valves 141 to 145 based on cool down mode or warm up mode. It may be one of a variety of computer processors that can be applied industrially to control on/off.

Memory 152 (MEMORY) is connected to the central processing unit 151. Memory 152 is a computer-readable recording medium that can be installed locally or remotely, for example, in a readily available storage medium such as random access memory (RAM), ROM, floppy disk, hard disk, or any other digital storage form. It may be at least one memory.

The support circuit 153 (SUPPORT CIRCUIT) is combined with the central processing unit 151 to support typical operations of the processor. This support circuit 153 may include a cache, power supply, clock circuit, input/output circuit, subsystem, etc.

In this embodiment, the controller 150 operates in a predetermined cool down mode in which liquid nitrogen (LN2) is supplied directly to the LNG fuel tank 20 or liquid nitrogen (LN2) is supplied through the atmospheric heat exchanger 160. The operation of the first to fifth solenoid valves 141 to 145 is selectively performed based on a predetermined warm up mode in which gaseous nitrogen is supplied to the LNG fuel tank 20 after heating the gaseous nitrogen. On/off control is performed, and this series of control processes can be stored in the memory 152. Typically, software routines may be stored in memory 152. Software routines may also be stored or executed by other central processing units (not shown).

Although the process according to the present invention has been described as being executed by software routines, it is also possible that at least part of the process according to the present invention is performed by hardware. As such, the processes of the present invention may be implemented as software running on a computer system, as hardware such as an integrated circuit, or as a combination of software and hardware.

Hereinafter, the operation of the floating offshore structure 100 according to this embodiment will be described.

As shown in FIG. 1, the ship 100 approaches and docks with the floating offshore structure 100 according to this embodiment.

Afterwards, for maintenance of the LNG fuel tank 20, the inside of the LNG fuel tank 20 is first emptied. That is, the LNG gas in the LNG fuel tank 20 is replaced with a stable inert gas.

When replacing an inert gas, cool down mode or warm up mode can be used, or all of these modes can be used. In this case, the first to fifth solenoid valves (151) are operated by the controller (150). You can proceed for on/off control of ~155).

When the inert gas replacement work is completed, there is no explosive gas such as LNG gas inside the LNG fuel tank 20, so workers can enter the LNG fuel tank 20 and perform maintenance. At this time, all parts where cracks and leaks occur in the LNG fuel tank 20 can be repaired, including cleaning of the LNG fuel tank 20.

When maintenance is completed, the above-mentioned cool down mode can be performed again to create an atmosphere so that the LNG fuel tank 20 can receive LNG fuel.

According to this embodiment, which operates with the structure described above, since it is a dedicated facility for maintenance of the LNG fuel tank 20, the ship 10 requiring maintenance of the LNG fuel tank 20 docks ( It can be used by docking, and as a result, there is no need to mount a maintenance device on each individual ship 10 as before, thereby eliminating the occurrence of various losses due to the installation of a maintenance device.

Figure 5 is a use state diagram of a floating offshore structure dedicated to LNG fuel tank maintenance according to the second embodiment of the present invention, and Figure 6 is a floating offshore structure dedicated to LNG fuel tank maintenance according to the third embodiment of the present invention. It is also the state of use of the structure.

In the embodiment of FIG. 5, the floating offshore structure 200 dedicated to LNG fuel tank maintenance is applied to a repair shipyard or a few small-scale facilities on the coast. At this time, the structure main body 210 may be a fixed structure fixed to the land.

In the case of FIG. 5, as in the first embodiment described above, the ship 10 of FIG. 1, which requires maintenance of the LNG fuel tank 20, moves to the floating offshore structure 100 applied to this embodiment and docks therewith. , maintenance of the LNG fuel tank 20 can be performed.

In the embodiment of FIG. 6, the floating marine structure 300 dedicated to LNG fuel tank maintenance may be an ordinary ship, especially a ship dedicated to maintenance, and the above-described devices on the structure main body 310, That is, devices such as an inert gas storage tank 120 are mounted.

In the case of FIG. 6, the floating marine structure 300 as a ship approaches the ship 10 that requires maintenance of the LNG fuel tank 20, docks with each other, and then proceeds with maintenance of the LNG fuel tank 20. You can. No matter what embodiment is applied, the effect of the present invention can be provided.

As such, the present invention is not limited to the described embodiments, and it is obvious to those skilled in the art that various modifications and changes can be made without departing from the spirit and scope of the present invention. Therefore, it should be said that such modifications or variations fall within the scope of the claims of the present invention.

10: Ship 20: LNG fuel tank
100: floating offshore structure 110: structure body
115: power device 120: inert gas storage tank
131: gas main supply pipe 132: gas bypass pipe
133: gas branch pipe 141: first solenoid valve
142: second solenoid valve 143: third solenoid valve
144: fourth solenoid valve 145: fifth solenoid valve
150: Controller 160: Standby heat exchanger
170: blower 180: docking arm

Claims (6)

A structural body placed adjacent to a ship requiring maintenance of an LNG fuel tank;
An inert gas storage tank mounted on the structure body and storing the inert gas in order to replace the LNG gas in the LNG fuel tank with an inert gas (unalive gas);
A gas main supply pipe connected to the inert gas storage tank and supplying the inert gas in the inert gas storage tank to the LNG fuel tank;
an atmospheric heat exchanger mounted on the structure body adjacent to the inert gas storage tank and heating the inert gas;
a gas bypass pipe provided via the atmospheric heat exchanger and both ends of which are connected to different positions of the gas main supply pipe; and
A floating marine structure dedicated to LNG fuel tank maintenance, including a gas branch pipe branched from the gas main supply pipe and forming a different path from the gas main supply pipe. delete delete According to paragraph 1,
A floating marine structure dedicated to LNG fuel tank maintenance further including a blower provided in the gas branch pipe. According to paragraph 1,
A first electromagnetic valve provided to be turned on/off in the main gas supply pipe between the inert gas storage tank and the gas bypass pipe;
second and third electromagnetic valves that can be turned on/off at both end areas of the gas bypass pipe;
a fourth solenoid valve that can be turned on/off in the gas main supply pipe between the gas bypass pipes;
A fifth electromagnetic valve provided in the gas branch pipe to be capable of being turned on/off; and
The inert gas is liquid nitrogen (LN2), and the liquid nitrogen (LN2) is heated through a predetermined cool down mode in which the liquid nitrogen (LN2) is supplied as is to the LNG fuel tank or through the atmospheric heat exchanger. After converting the gaseous nitrogen into gaseous nitrogen, the operation of the first to fifth solenoid valves is selectively turned on/off based on a predetermined warm up mode for supplying the gaseous nitrogen to the LNG fuel tank. ) A floating offshore structure dedicated to LNG fuel tank maintenance that further includes a controller to control it. According to paragraph 1,
A floating marine structure dedicated to LNG fuel tank maintenance, which is provided on the structure main body and further includes a docking arm for docking with the ship for connection to a neighboring ship approaching the structure main body.

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