KR20100134838A - Apparatus for heating cofferdam and floating marine structure having the apparatus - Google Patents

Abstract

PURPOSE: A cofferdam heating apparatus, which is configured as a single integrated system where a pipe extended from a heater installed inside a lateral cofferdam is arranged inside a longitudinal cofferdam, and a floating marine structure having the same are provided. CONSTITUTION: A cofferdam heating apparatus for providing heat to the inside of a lateral cofferdam(20) and a longitudinal cofferdam(30) arranged between storage tanks(10) in a floating marine structure comprises a heat transfer unit, a pump, and a heat exchanger. The heat transfer unit is arranged inside the lateral cofferdam and the longitudinal cofferdam and transfers the heat provided from an external heat source to the inside of the lateral cofferdam and the longitudinal cofferdam. The pump circulates heat exchange media flowing through the heat transfer unit. The heat exchanger heats the heat exchange media which are cooled by passing through the inside of the longitudinal cofferdam and the lateral cofferdam.

Description

Cofferdam heater and floating offshore structure with cofferdam heater {APPARATUS FOR HEATING COFFERDAM AND FLOATING MARINE STRUCTURE HAVING THE APPARATUS}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cofferdam heating device provided in a floating offshore structure that can be used suspended at sea. When a directional cofferdam is provided, it is related with the cofferdam heating apparatus formed by arrange | positioning the piping extended from the heating apparatus provided in the width direction cofferdam inside the longitudinal cofferdam.

Natural gas is transported in gaseous form through onshore or offshore gas piping, or liquefied in the form of liquefied natural gas (LNG) or liquefied petroleum gas (LPG), followed by LNG carriers or LPG. It is transported to a remote consumer while stored in a transport. Liquefied natural gas is obtained by cooling natural gas to cryogenic temperature (approximately -163 ℃), and its volume is reduced to about 1/600 than natural gas in gas state, so it is very suitable for long distance transportation through sea.

LNG transporter for loading and unloading LNG to land requirements by operating the sea with LNG The vessel includes a storage tank (commonly referred to as a "cargo hold") capable of withstanding cryogenic temperatures of liquefied natural gas.

Recently, there is a growing demand for floating offshore structures such as LNG Floating, Production, Storage and Offloading (FPSO) or LNG Floating Storage and Regasification Units (FSRUs). Includes a storage tank installed.

LNG FPSOs are floating offshore structures that are used to liquefy the produced natural gas directly from the sea and store it in storage tanks and, if necessary, to transport LNG stored in the storage tanks to LNG carriers. In addition, LNG FSRU is a floating offshore structure that stores LNG unloaded from LNG carriers in a storage tank at sea far from the land, and then vaporizes LNG as needed to supply land demand.

As described above, a storage tank for storing LNG in a cryogenic state is installed in an offshore structure such as an LNG carrier, an LNG RV, an LNG FPSO, or an LNG FSRU that transports or stores a liquid cargo such as LNG.

These storage tanks can be classified into Independent Type and Membrane Type, depending on whether the load directly affects the insulation. Membrane type storage tanks are generally divided into GT NO 96 type and TGZ Mark III type, and standalone storage tanks are divided into MOSS type and IHI-SPB type.

The GT and TGZ tank structures described above are described in U.S. Patent Nos. 6,035,795, 6,378,722, 5,586,513, and U.S. Patent Publication Nos. 2003-0000949 and the like, and Korean Patent Publication Nos. 10-2000-0011347 and 10-2000- 0011346 and the like. In addition, the structure of the stand-alone storage tank is described in Korean Patent Nos. 10-15063 and 10-305513.

In general, a membrane tank is used as a storage tank for storing LNG, and FIG. 1 shows an example of a conventional membrane tank used for storing liquefied gas.

As shown in FIG. 1, the conventional membrane type liquefied gas storage tank 10 for storing liquefied gas such as LNG includes an inner wall surface 2 or a cofferdam partition 5 of the hull 1 (see FIG. 2). ), The secondary heat insulating wall 13, the secondary sealing wall 14, the primary heat insulating wall 15, and the primary sealing wall 16 are sequentially stacked. A ballast tank 3 is provided inside the hull 1 to stably maintain the draft of the floating offshore structure.

As shown in FIG. 2, the liquefied gas storage tanks 10 disposed inside the hull 1 are separated by a widthwise cofferdam 20 extending in the width direction of the hull. The cofferdam is a grid-shaped structure in which a void space is provided therein, and partitions the internal space of the floating marine structure so that a membrane-type storage tank can be installed in each compartment. Such cofferdams are conventionally used to partition between a plurality of storage tanks arranged in a row along the longitudinal direction of a floating offshore structure.

Although the inner wall surface 2 and the cofferdam partition wall 5 are not in direct contact with the LNG, the LNG contained in the liquefied gas storage tank 10 is in a cryogenic state of approximately -163 ° C. 2) and the temperature of the iron plate constituting the cofferdam bulkhead 5 is extremely low and brittleness becomes weak. Therefore, the inner wall surface 2 and the cofferdam partition 5 should be made of low temperature steel that is resistant to low temperatures.

In addition, the cofferdam 20 located between the storage tanks 10 is a closed space, so that heat is not supplied from the outside so that the internal temperature may drop to about -60 ° C. Therefore, it is necessary to heat the inner space of the cofferdam 20 and the cofferdam partition 5 to maintain a predetermined temperature or more.

The present invention for solving these problems, when the widthwise cofferdam and the longitudinal cofferdam is installed in order to arrange the liquefied gas storage tank in two rows in the floating offshore structure, it is installed inside the widthwise cofferdam It is an object of the present invention to provide a cofferdam heating device comprising a system by arranging a pipe extending from the heating device in the longitudinal cofferdam.

According to an aspect of the present invention for achieving the above object, a plurality of liquefied gas storage tanks are arranged in two rows by a longitudinal cofferdam installed in the longitudinal direction and the widthwise cofferdam installed in the width direction In the structure, a cofferdam heating device for supplying heat to the longitudinal cofferdam and the widthwise cofferdam disposed between the storage tanks, the inside of the widthwise cofferdam and the longitudinal cofferdam A cofferdam heating apparatus is provided that includes heat transfer means arranged to transfer heat supplied from an external heat source together into the widthwise cofferdam and the longitudinal cofferdam.

The cofferdam heating device further includes a pump for circulating a heat exchange medium flowing through the heat transfer means, and a heat exchanger for heating the cooled heat exchange medium while passing through the widthwise cofferdam and the longitudinal cofferdam. It is preferable to include.

The heat transfer means is a pipe arranged inside both the widthwise cofferdam and the longitudinal cofferdam, and preferably a heat exchange medium flows through the inside of the pipe.

The pipe is preferably arranged to sequentially cycle the interior of the widthwise cofferdam and the longitudinal cofferdam.

The pipe preferably forms one or more closed circuits.

The pipe constitutes an open circuit, wherein it is preferable to use seawater outside the floating offshore structure as the heat exchange medium.

It is preferable to use any one selected from antifreeze, fresh water and sea water as the heat exchange medium.

According to still another aspect of the present invention, there is provided a floating offshore structure that is used floating on the sea, comprising: a plurality of liquefied gas storage tanks arranged in two rows inside the floating offshore structure to receive liquefied gas; A widthwise cofferdam and a longitudinal cofferdam disposed along the width direction and the longitudinal direction of the floating offshore structure so as to be formed between the liquefied gas storage tanks arranged in two rows; A cofferdam heating device capable of supplying heat to the widthwise cofferdam and the longitudinal cofferdam; The cofferdam heating device includes: the cofferdam heating device arranged in the widthwise cofferdam and the longitudinal cofferdam to transfer heat supplied from an external heat source to the inside of the cofferdam and the longitudinal cofferdam; A floating offshore structure is provided, comprising a heat transfer means for.

The cofferdam heating device further includes a pump for circulating a heat exchange medium flowing through the heat transfer means, and a heat exchanger for heating the cooled heat exchange medium while passing through the widthwise cofferdam and the longitudinal cofferdam. It is preferable to include.

The floating offshore structure is preferably any one selected from among LNG FPSO, LNG FSRU, LNG transport ship, and LNG RV, which are used while suspended in the sea while having a storage tank for storing liquefied gas.

According to another aspect of the present invention, in the floating offshore structure in which a plurality of liquefied gas storage tanks are arranged in two rows by a longitudinal cofferdam installed in the longitudinal direction and the widthwise cofferdam installed in the width direction, the storage A cofferdam heating method for supplying heat to the longitudinal cofferdam and the width cofferdam disposed between tanks, the method comprising: a heat transfer means arranged inside the width cofferdam and the longitudinal cofferdam; Thereby, a cofferdam heating method is provided, which transfers heat supplied from an external heat source to both the widthwise cofferdam and the longitudinal cofferdam and heats it.

The heat transfer means is preferably a cofferdam heating method, characterized in that for supplying heat sequentially into the widthwise cofferdam and the longitudinal cofferdam.

According to the present invention as described above, in the case where the widthwise cofferdam and the longitudinal cofferdam are installed to arrange the liquefied gas storage tanks in two rows in the floating offshore structure, the heating device is installed inside the widthwise cofferdam A cofferdam heating device consisting of a system can be provided by arranging a pipe extending from the inside of the longitudinal cofferdam.

Hereinafter, a cofferdam heating apparatus and method according to a preferred embodiment of the present invention will be described in detail with reference to the drawings.

3 is a plan view of a floating offshore structure for explaining the cofferdam heating apparatus according to the present invention. And FIG. 4 is a sectional front view of the floating offshore structure for explaining the cofferdam heating apparatus according to the present invention, Figure 5 is a side of the floating offshore structure for explaining the cofferdam heating apparatus according to the present invention A cross section is shown.

In the present specification, a floating offshore structure is a concept including both a vessel and various structures used while floating on the sea while having a storage tank for storing liquefied gas such as LNG or LPG. In addition to production, storage and offloading, LNG includes both floating storage and regasification units (FSRUs), LNG carriers and LNG regasification vessels (RVs).

Conventionally, only a structure in which storage tanks installed inside such floating offshore structures are arranged in one row along the longitudinal direction of the hull is known, but a two-row arrangement structure of storage tanks has been developed to reduce the impact due to sloshing. have.

Sloshing refers to a phenomenon in which a liquid substance contained in a storage tank, that is, LNG, flows when a vessel moves in various sea conditions, and the wall surface of the storage tank is severely impacted by sloshing. This sloshing phenomenon occurs more severely during partial loading.

Since the sloshing phenomenon inevitably occurs during the operation of the ship, it is necessary to design the storage tank structure to have sufficient strength to withstand the load due to the sloshing.

As described above in the background, since the LNG contained in the liquefied gas storage tank is a cryogenic state of about -163 ° C., the temperature of the iron plate forming the storage tank may decrease due to the cold air of LNG, and thus the strength of the storage tank may be weakened. Therefore, there is a high risk of damage due to the impact force due to the sloshing phenomenon.

In addition, the cofferdam is located between the storage tank is a closed space so that the heat is not supplied from the outside, the internal temperature may drop to about -60 ℃. Therefore, it is necessary to heat the inside of the cofferdam to maintain a certain temperature or more.

As shown in FIG. 3, in the case of the floating offshore structure in which the storage tanks are arranged in two rows, the width cofferdam 20 installed along the width direction of the hull between the storage tanks 10 arranged in two rows. In addition to the longitudinal cofferdam 30 is installed in the center of the hull along the longitudinal direction is installed inside the floating offshore structure.

In the case where two rows of liquefied gas storage tanks are arranged in this way, a longitudinal cofferdam partition wall 7 is provided around the longitudinal coffer dam 30, and a widthwise cofferdam partition wall around the longitudinal cofferdam 20 ( 5) is installed. Thus, as seen in FIG. 3, each storage tank 10 can be partitioned by a pair of transverse cofferdam bulkheads 5 facing the pair of longitudinal cofferdam bulkheads 7, and these On the surfaces of the longitudinal cofferdam bulkhead 7 and the widthwise cofferdam bulkhead 5, as shown in FIG. 1, the secondary heat insulating wall 13, the secondary sealing wall 14, and the primary heat insulating wall 15 are shown. And the primary sealing wall 16 are sequentially stacked to form the storage tank 10.

Although not shown, the space between the longitudinal cofferdam bulkheads 7, ie the longitudinal cofferdam 30, can be used as part of the central ballast tank.

In addition, when two rows of liquefied gas storage tanks are disposed, a cofferdam heating device may be installed in the longitudinal cofferdam 30 and the cofferdam 20 in the width direction. According to the present invention, these longitudinal cofferdams and cofferdam heating devices provided in the widthwise cofferdams are connected by one pipe as described later.

3 to 5, the cofferdam heating device 40 according to the present invention is arranged inside the widthwise cofferdam 20 and the longitudinal cofferdam 30, and the widthwise cofferdam ( 20) and heat transfer means for transferring heat supplied from a heat source outside the longitudinal cofferdam 30 to the interior of the width cofferdam 20 and the longitudinal cofferdam 30.

As the heat transfer means, a pipe 41 arranged inside the widthwise cofferdam 20 and the longitudinal cofferdam 30 can be used. According to the present invention, the pipe 41 is not only arranged inside the widthwise cofferdam 20 or only inside the longitudinal cofferdam 30, but the inside and the length of the widthwise cofferdam 20. Arranged over both interiors of the directional cofferdam 30.

Heat exchange medium may flow inside the pipe 41. In addition, the cofferdam heating device 40 according to the present invention includes a pump 42 for circulating a heat exchange medium flowing in the pipe 31, a widthwise cofferdam 20 and a longitudinal cofferdam 30. It may further include a heat exchanger 43 for heating the cooled heat exchange medium while passing through the interior.

The pipe 41 of the cofferdam heating device 40 according to the present invention may form a closed loop, and the pump 42 and the heat exchanger 43 may be installed outside the cofferdams 20 and 30. .

The heat exchange medium heats the interior of the cofferdams 20, 30 by passing heat to the air or ballast water around the pipes 41 while passing through the pipes 41 arranged inside the cofferdams 20, 30. Can be.

4 and 5, the heat exchange medium heated in the heat exchanger 43 starts in the longitudinal cofferdam 30 and sequentially circulates the left and right sides of the cofferdam 20 in a sequential manner. The pipe 41 is arranged so that it can be transferred back into the longitudinal cofferdam 30, circulate inside the longitudinal cofferdam 30, and then return to the heat exchanger 43 through the pump 42. .

This arrangement of the pipes 41 is merely an example and does not limit the present invention. That is, the arrangement of the pipe 41 may be modified such that the heat exchange medium heated by the heat exchanger 43 circulates inside the longitudinal cofferdam 30 and then circulates inside the width cofferdam 20.

4 and 5 also show that the pipe 41 passes through the upper portion of the longitudinal cofferdam 30 as it passes between the widthwise cofferdam 20 and the longitudinal cofferdam 30. The pipe 41 may be arranged to pass through the middle or bottom portion of the longitudinal cofferdam 30.

The cofferdam heating device according to the invention may consist of one or more closed loops. If the pipe 41 has a plurality of closed loops, one closed loop may become inoperable or another closed if only one closed loop cannot deliver sufficient heat to the interior of the cofferdam 20, 30. It is desirable to use a loop to heat the interior of the cofferdams 20 and 30.

According to the present invention, in a cooling apparatus installed in a floating offshore structure, which needs to be cooled during operation, a coolant heated by itself while cooling the cooling apparatus is used as a heat exchange medium. By supplying the inside of the cofferdams 20 and 30 through the pipe 41, the heat can be supplied to the inside of the cofferdams 20 and 30.

The refrigerant cooled while passing through the interior of the cofferdams 20 and 30, i.e., the heat exchange medium, is returned to the urine cooling device installed in the floating offshore structure and needs to be cooled during operation. Supply the cold heat to itself and it can be heated. That is, as a refrigerant for cooling the cooling unit, in which cooling is essential, such as an engine, a boiler, a turbine, a generator, and the like, a heat exchange medium cooled in the cofferdam may be utilized. In this case, the pipe 41 is configured to extend to the urine cooling device.

Alternatively, the heat exchanger 43 may transfer the coolant of the heat exchange medium to the coolant in the coolant circuit by heat-exchanging the coolant flowing in the coolant circuit of the cooler device and the heat exchange medium flowing in the pipe 41.

As an example of the urine cooling apparatus installed in a floating offshore structure, Engines, such as a propulsion engine and a generator engine; With a boiler; Gas turbines; Generator; Conditioners such as an air conditioner and an atmospheric conditioner; Compressors such as an air compressor; Condenser such as Cargo pump turbine vacuum condenser; Cooler such as Stern tube lubricating oil cooler, Main engine jacket fresh water cooler, Main lubricating oil cooler, Main engine scavenger air cooler, Cargo pump turbine lubricating oil cooler, Generator engine and generator engine lubricating oil cooler; Preheaters, such as a main engine jacket cooling water preheater, Generator engine high temperature and jacket, and Generator engine jacket preheater; Provision refrigerant plant; Shaft bearing; Air ejector etc. can be mentioned. In addition, all devices installed in a floating offshore structure and requiring cooling during operation can be utilized as a urine cooling device.

In addition, the pipe of the longitudinal cofferdam heating apparatus according to the present invention may be arranged in the form of an open loop, as the heat exchange medium circulating in the pipe 41 may be used antifreeze, fresh water, seawater and the like.

When seawater is supplied through a pipe arranged in the form of an open loop, the suctioned seawater is supplied to the urine cooling device to receive heat from the urine cooling device, and then the heated hot seawater is piped through the pipe 41. It is supplied to the inside of dam 20,30. While moving inside the copper dams 20 and 30, the hot sea water dissipates heat and cools itself. The cooled seawater is discharged to the outside of the floating offshore structure.

In both cases where the pipes are arranged in the form of a closed loop or an open loop as described above, in the cofferdam heating apparatus of the present invention, the temperature of the heat exchange medium such as seawater heated by the urine cooling apparatus is changed to the cofferdam 20. 30) When not sufficient to heat the interior, a heater may be provided to further heat this heat exchange medium.

In the cofferdam heating apparatus of the present invention, when the temperature of the heat exchange medium cooled inside the cofferdams 20 and 30 is too high to be suitable for use in the urine cooling apparatus, or in terms of environmental pollution, it is suspended. When not suitable for evacuation of the offshore structure, a cooler may be provided to further cool this heat exchange medium.

On the other hand, the arrangement of the pipe 41 arranged in the cofferdam (20, 30) may be changed depending on the design other than those shown in Figs.

In addition, the cofferdam heating apparatus of the present invention configured and operated as described above may be installed when manufacturing a floating offshore structure, such as a ship or an offshore plant, and in addition to the floating offshore structure being manufactured and used. It may be installed. Even when added to the floating marine structure in use, the cofferdam heating device of the present invention can be configured by utilizing the existing cooling apparatus such as an engine, a boiler, a gas turbine, a generator, and the like. It is possible to quickly install the cofferdam heating apparatus of the present invention.

In addition, although the pump 42 and the heat exchanger 43 are shown in FIG. 5 as being located on the deck, they can be installed inside the hull of the engine room, and the present invention is not limited by the installation position.

As described above, the present invention has been described with reference to the illustrated drawings, but the present invention is not limited to the above-described embodiments and drawings, and has a general knowledge in the technical field to which the present invention belongs within the claims. Of course, various modifications and variations can be made by them.

1 is a view showing an example of a conventional membrane type LNG storage tank,

2 is a plan view showing a schematic structure of a conventional LNG carrier;

3 is a plan view of a floating offshore structure for explaining the cofferdam heating apparatus according to the present invention, and

4 and 5 are a front and partial side cross-sectional view of the floating offshore structure for explaining the cofferdam heating apparatus according to the present invention.

Description of the Related Art

1: hull 2: inner wall surface

3: ballast tank 5: width cofferdam bulkhead

7: longitudinal cofferdam bulkhead 10: storage tank

13: secondary insulation wall 14: secondary sealing wall

15: primary insulation wall 16: primary sealing wall

20: widthwise cofferdam 30: longitudinal cofferdam

40: cofferdam heating device 41: pipe

42: pump 43: heat exchanger

Claims (13)

In a floating offshore structure in which a plurality of liquefied gas storage tanks are arranged in two rows by a longitudinal cofferdam installed in a longitudinal direction and a width coperdam installed in a width direction, the longitudinal direction disposed between the storage tanks. A cofferdam heating device for supplying heat into a cofferdam and the widthwise cofferdam, And heat transfer means arranged in the widthwise cofferdam and the longitudinal cofferdam to transfer heat supplied from an external heat source together into the widthwise cofferdam and the longitudinal cofferdam. Copper dam heater. The method according to claim 1, And a pump for circulating the heat exchange medium flowing through the heat transfer means, and a heat exchanger for heating the cooled heat exchange medium while passing through the widthwise cofferdam and the longitudinal cofferdam. Dam heater. The method according to claim 1, And the heat transfer means is a pipe arranged inside both of the widthwise cofferdam and the longitudinal cofferdam, and the heat exchange medium flows through the inside of the pipe. The method according to claim 3, And the pipe is arranged to sequentially cycle the interior of the widthwise cofferdam and the longitudinal cofferdam. The method according to claim 3, And the pipe constitutes one or more closed circuits. The method according to claim 3, The pipe dam heating apparatus, characterized in that the pipe constitutes an open circuit. The method according to claim 6, A cofferdam heater, characterized in that seawater outside the floating offshore structure is used as the heat exchange medium. The method according to claim 3, The copper dam heating apparatus, characterized in that any one selected from antifreeze, fresh water and sea water is used as the heat exchange medium. Floating offshore structures used to float on the sea, A plurality of liquefied gas storage tanks arranged in two rows in the floating offshore structure to receive liquefied gas; A widthwise cofferdam and a longitudinal cofferdam disposed along the width direction and the longitudinal direction of the floating offshore structure so as to be formed between the liquefied gas storage tanks arranged in two rows; A cofferdam heating device capable of supplying heat to the widthwise cofferdam and the longitudinal cofferdam; Including; The cofferdam heating device includes heat transfer means for transferring heat supplied from an external heat source inside the widthwise cofferdam and the longitudinal cofferdam into the widthwise cofferdam and the longitudinal cofferdam. Floating offshore structure comprising a. The method according to claim 9, The cofferdam heating device further includes a pump for circulating a heat exchange medium flowing through the heat transfer means, and a heat exchanger for heating the cooled heat exchange medium while passing through the widthwise cofferdam and the longitudinal cofferdam. Floating offshore structure comprising a. The method according to claim 9, The floating offshore structure is a floating offshore structure, characterized in that any one selected from the LNG FPSO, LNG FSRU, LNG transport ship, and LNG RV used in the floating while having a storage tank for storing liquefied gas . In a floating offshore structure in which a plurality of liquefied gas storage tanks are arranged in two rows by a longitudinal cofferdam installed in a longitudinal direction and a width coperdam installed in a width direction, the longitudinal direction disposed between the storage tanks. A cofferdam heating method for supplying heat to a cofferdam and the widthwise cofferdam, The heat transfer means arranged inside the widthwise cofferdam and the longitudinal cofferdam transfers heat supplied from an external heat source to both the widthwise cofferdam and the longitudinal cofferdam and heats it. Copper dam heating method, characterized in that. The method according to claim 12, And the heat transfer means sequentially supplies heat to the widthwise cofferdam and the longitudinal cofferdam.

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