KR20150011439A - Floating marine structure and its temperature controlling method - Google Patents

Abstract

In the present invention, disclosed are a floating marine structure which can control a control temperature of a coffer dam depending on sailing conditions controlled at sub-zero temperatures and a type of an operation by lowering the control temperature of the coffer dam and reducing a boil-off rate (BOR) at low costs, and a method for controlling the temperature thereof. The floating marine structure of the present invention comprises: a coffer dam installed among a plurality of LNG storage tanks, arranging the multiple LNG storage tanks in several rows in at least one of the longitudinal direction and the width direction of a hull, and controlled at sub-zero temperatures; and a heating unit installed in the coffer dam and heating the coffer dam. The coffer dam reduces a BOR generated by heat-exchanging between LNG stored in the coffer dam and the multiple LNG storage tanks as controlled at sub-zero temperatures, and the sub-zero temperatures are changed to above-zero temperatures by heating the heating unit.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a floating structure and a temperature control method,

The present invention relates to a floating structure and a method of controlling the temperature of the LNG storage tank. More particularly, the present invention relates to a floating structure capable of reducing the BOR (Boil-off Ratio) by reducing the heat transfer between the cofferdams and the LNG stored in the LNG storage tank Structures and temperature control methods.

In general, natural gas is transported in the form of gas through land or sea gas pipelines, or stored in a LNG carrier in the form of liquefied natural gas (hereinafter referred to as "LNG"), Lt; / RTI >

Such LNG is obtained by cooling natural gas to a cryogenic temperature, for example, approximately -163 DEG C, and its volume is reduced to about 1/600 of that of natural gas in a gaseous state, so that it is suitable for long distance transportation through the sea.

These LNGs are transported through LNG transporting vessels, transported through the sea, unloaded to landfill sites, carried on LNG RV (LNG Regasification Vessel), transported through the sea, reached to land requirements, recharged and unloaded as natural gas LNG carriers and LNG RVs are equipped with LNG storage tanks (also called "cargo holds") that can withstand the extreme temperatures of LNG.

In addition, demand for marine structures such as LNG FPSO (Floating, Production, Storage and Offloading) and LNG FSRU (Floating Storage and Regasification Unit) is gradually increasing, and LNG transport or LNG storage Tanks are included.

Here, the LNG FPSO is a marine structure used to directly liquefy natural gas produced from the sea and store it in a storage tank, and to transfer the LNG stored in the storage tank to the LNG transport if necessary.

LNG FSRU is an offshore structure that stores LNG unloaded from an LNG carrier in offshore water and stores it in a storage tank, and then supplies LNG to the demanding customers on demand.

These LNG storage tanks are divided into independent tank type and membrane type depending on whether the insulation for storing the LNG at a cryogenic temperature directly acts on the load of the cargo, The tank is divided into the MOSS type and the IHI-SPB type, and the membrane type storage tank is divided into the GT NO 96 type and the TGZ Mark III type.

Among the conventional LNG storage tanks, GT NO 96, which is a membrane type, has a primary barrier and a secondary barrier made of Invar steel (36% Ni) having a thickness of 0.5 to 0.7 mm, The primary sealing wall is located on the LNG side and the secondary sealing wall is located on the inner surface side of the hull so as to double-wrap the LNG.

A primary heat insulating wall is provided in a space between the primary sealing wall and the secondary sealing wall, and a secondary heat insulating wall is provided in a space between the secondary sealing wall and the inner hull. The primary heat insulating wall and the secondary insulating wall The walls minimize the transfer of heat from the outside of the LNG storage tank to the LNG.

Meanwhile, since the LNG stored in the LNG storage tank is stored at about -163 ° C, which is the vaporization temperature at normal pressure, when heat is transferred to the LNG, the LNG is vaporized and a boil off gas (hereinafter referred to as BOG) is generated.

In the case of membrane type LNG storage tanks, when cold LNG storage tanks are installed continuously, the temperature of the steel between them suddenly drops and brittle fracture can occur.

To prevent this, a space called a cofferdam is placed between the LNG storage tanks to prevent the low temperature damage of the LNG.

However, even if the coffer dam is installed, the temperature of the steel of the copper dam bulkhead contacting with the LNG cargo due to cryogenic LNG may fall below -60 ° C. Normal steel is damaged at low temperature brittleness when exposed to -60 ° C.

As a countermeasure, Copper Dam can be made of cryogenic material such as stainless steel or aluminum, but if the cryogenic material is used, the price of ship will increase sharply.

Therefore, when the copper dam and the LNG storage tank are installed, the temperature of the copper dam is controlled at 5 ° C. and the bulkhead of the copper dam is made of a relatively inexpensive steel which can withstand room temperature.

In the case of conventional LNG carriers, when the temperature of the cofferdams is less than 5 ℃, the heating system operates and always keeps 5 ℃ or more. Conventional LNG carriers are equipped with a glycol heating system or an electric heating system.

Therefore, conventional LNG carriers are always designed and operated at at least 5 ° C for the cofferdams, and BOR is also generated at these temperature conditions.

Korea Public Registration Bulletin 2011-0058086 (Samsung Heavy Industries Co., Ltd.) 2011. 06. 01.

Currently, the LNG carrier market is sensitive to the BOR level at the contracting stage. For example, in the past, 0.15% BOR was a contract condition, but in recent years, 0.125%, 0.10% or 0.095% BOR has been proposed as a contract condition.

However, currently membrane type tanks are equipped with insulation walls in the cargo hold. Since the LNG cargo hold insulation wall must be capable of withstanding the load transferred from the LNG cargo to the cargo hold in addition to the insulation performance, there is a lot of research, design change, and cost increase when the insulation of the existing LNG cargo hold is changed to improve the insulation performance .

In fact, even if there is an LNG hold wall insulation wall satisfying 0.13% BOR, there is much research, time, and cost to reduce the BOR by 4% when 0.125% comes to the BOR requirement of the shipowner.

Also, even if there is an LNG cargo hold insulation wall that guarantees 0.103% BOR, if the shipowner presents a BOR of 0.10%, it is impossible to apply this LNG cargo hold and the LNG carrier can not be ordered. Currently, 1% of the market is able to compete in favor of shipbuilding if the BOR declines, which is the current LNG carrier market.

On the other hand, the development of the existing BOR reduction technology is to improve the performance of the LNG cargo hold insulation wall. At present, a small amount of BOR is required in the market, so the most discussed method is to increase the thickness of the LNG cargo hold.

However, increasing the thickness of the LNG hold reduces the volume of LNG storage. Alternatively, the size of the vessel increases to maintain the same hold volume.

Further, as the thickness of the cargo hold increases, the structure of the cargo hold is weaker, so research should be conducted to reinforce it.

Accordingly, it is an object of the present invention to reduce the BOR by reducing the control temperature of the cofferdams, and to reduce the BOR by controlling the cofferdam control temperature, which is controlled by the subzero temperature, And a method of controlling the temperature.

According to an aspect of the present invention, there is provided a coffer dam provided between a plurality of LNG storage tanks, wherein the plurality of LNG storage tanks are arranged in multiple rows in at least one of a longitudinal direction and a width direction of the hull, And a heating unit provided in the cofferdams for heating the cofferdams, wherein the cofferdams are controlled at a sub-zero temperature so that the BOR generated by the heat transfer between the COP dam and the LNG stored in the plurality of LNG storage tanks Wherein the temperature of the freezing structure is changed to the temperature of the heating furnace image of the heating unit.

The cofferdams comprising: a pair of bulkheads spaced apart from each other between the plurality of LNG storage tanks; And a space portion provided by the pair of bulkheads and the inner wall of the hull, and the sub-temperature can be changed to the image temperature by heating the pair of bulkheads with the heating portion.

When the bulkhead of the copper dam is made of a material that can withstand temperatures of -30 to 0 占 폚, the copper dam can be thermally changed in a range of -30 to 70 占 폚.

When the bulkhead of the copper dam is made of low-temperature steel capable of withstanding up to -55 占 폚, the copper dam can be thermally changed in the range of -55 to 70 占 폚.

When the fuel consumption of the floating structure is large, the temperature of the cofferdam is increased to increase the generation of boil-off gas (BOG) and used as fuel. When the fuel consumption of the offshore structure is small, The generation of the BOG can be reduced.

The temperature of the coffer dam can be controlled by an image by heating the coffer dam by the heating unit so that an operator can enter the inside of the coffer dam.

The temperature of the sub-subzero of the cofferdam can be changed to the temperature of the image by the high-temperature dry air supplied to the inside of the cofferdam.

When the internal pressure of the LNG storage tank is higher than the set pressure of the LNG storage tank and the internal pressure of the LNG storage tank is lower than the set pressure of the LNG storage tank, .

The floating structure may be any one selected from LNG FPSO, LNG FSRU, LNG transport, LNG RV and FLNG.

According to another aspect of the present invention, there is provided a method of controlling a COP dam disposed between a plurality of LNG storage tanks at a sub-zero temperature to increase the BOR generated by heat transfer between the COP dam and the LNG stored in the plurality of LNG storage tanks, off rate of the hull is lowered while the temperature of the sub-sea is changed by the heating of the hitting part provided on the hull to maintain the temperature of the image.

According to another aspect of the present invention, there is provided a method of controlling a COP dam, Controlling the coffer dam to a temperature of an image so that an operator enters the coffer dam controlled at a subzero temperature; And controlling the cofferdams to a sub-zero temperature when the operator exits the coffer dam.

The copper dam can be controlled in a temperature range of -55 to 70 캜.

Embodiments of the present invention can reduce the BOR (Boil-off Rate) generated by the heat transfer between the COP dam and the LNG stored in the plurality of LNG storage tanks by controlling the temperature of the copper damper at a low temperature, The control temperature is raised to increase the BOG and when the BOG is generated in a large amount, the control temperature can be lowered to adjust the BOG to be less. In order to inspect the inside of the copper dam, the operator enters the inside of the copper dam If necessary, the cofferdams can be controlled to the temperature of the image to enable the operator to enter the cofferdams.

1 is a side view schematically showing a state in which a coffer dam is installed in a floating type floating structure according to a first embodiment of the present invention.
2 is a sectional view taken along the line II-II in Fig.
3 is a sectional view taken along the line III-III in Fig.
FIG. 4 is a plan sectional view showing a state in which a coffer dam is provided between two rows of LNG storage tanks in the floating structure shown in FIG. 1. FIG.
5 is a sectional view taken along the line IV-IV in Fig.
6 is a table showing the steel grade specified by the IGC.
7 is a table showing a calculation result of the BOR generated by the temperature control of the copper dam in the first embodiment of the present invention.
8 is a view schematically showing a state in which a heating unit is provided in a floating structure in the first embodiment of the present invention.
9 is a view schematically showing a state in which a thermal insulating material is provided in a copper dam in a thermal insulation system of a floating structure according to a second embodiment of the present invention.
10 is a perspective view schematically showing a state in which a heat insulating material is provided in an area " A " in Fig.
11 is a perspective view schematically showing a state in which a heat insulating material is provided in a region " B " in Fig.
Fig. 12 is a view schematically showing a heat insulating material damage preventing member provided to prevent the heat insulating material from being damaged in the " C " area in Fig.
13 is a table showing calculation results of BOR generated by controlling the temperature of the copper dam by the heat insulating material shown in FIG.
FIG. 14 is a view schematically showing a state in which a bulkhead of a copper dam in a floating structure according to a third embodiment of the present invention is connected to an inner hull without extending to an outer hull.
Fig. 15 is a modified embodiment of Fig. 14 in which a copper dam is provided in place of the bulkhead shown in Fig. 14 and a heat insulating material is provided in the copper dam.
FIG. 16 is a table showing the calculation results of the BOR generated by manufacturing the bulkhead shown in FIG. 13 with a cryogenic material and controlling the temperature of the copper dam.
17 is a view schematically showing a gas supply unit in a floating type floating structure according to a fourth embodiment of the present invention.
18 is a table showing calculation results of the BOR generated by controlling the temperature of the coffer dam shown in FIG.
19 is a view schematically showing control of the temperature of the cofferdams according to the pressure change of the LNG storage tank in the floating structure according to the fifth embodiment of the present invention.
20 is a view schematically showing a state in which a heat insulating material is provided in a trunk deck space and a side passage in a thermal insulation system of a floating marine structure according to a sixth embodiment of the present invention.
21 is a table showing calculation results of the BOR generated by controlling the temperature of the inner hull adjacent to the trunk deck space and the side passages shown in Fig.
22 is a view schematically showing a state in which a thermal insulating material is provided in a ballast tank in a thermal insulation system of a floating structure according to a seventh embodiment of the present invention.
23 is a table showing the calculation result of the BOR generated by controlling the temperature of the inner hull in contact with the ballast tank.

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. Like reference symbols in the drawings denote like elements.

In this specification, the floating floating structure refers to a concept including all kinds of ships and various structures that are floated on the sea while having a storage tank for storing LNG, LNG FPSO (Floating, Production, Storage and Offloading) Floating Storage and Regulation Unit (FSRU), LNG carrier, and LNG RV (LNG Regasification Vessel).

1 is a side view schematically showing a state in which a copper dam is installed on a floating type floating structure according to a first embodiment of the present invention, FIG. 2 is a sectional view taken along line II-II in FIG. 1, FIG. 4 is a plan sectional view showing a state in which a coffer dam is provided between two rows of LNG storage tanks in the floating structure shown in FIG. 1, and FIG. 5 is a cross- FIG. 6 is a table showing the steel grade specified by the IGC, and FIG. 7 is a table showing the steel grade of the BOR generated by the temperature control of the copper dam in the first embodiment of the present invention. FIG. 8 is a view schematically showing a state in which a heating unit is provided in a floating structure in the first embodiment of the present invention. FIG.

The present embodiment controls the cofferdams 10 at a sub-zero temperature to reduce the boil-off rate (BOR) generated by the heat transfer from the coffer dam 10 to the interior of the LNG storage tank T.

As shown in these drawings, the floating marine structure 1 according to the present embodiment is provided between a plurality of LNG storage tanks T provided in one or more rows in the longitudinal direction of the hull, And a controlled coffer dam (10).

The cofferdam 10 is provided in a plurality of LNG storage tanks T provided in one or more rows in the longitudinal direction of the hull and is arranged in multiple rows in the longitudinal direction of the hull as shown in Figs. May be provided between the plurality of LNG storage tanks T or may be provided between the LNG storage tanks T arranged in two rows in the width direction and the longitudinal direction of the hull as shown in Figs. .

In this embodiment, the cofferdams 10 are controlled to a sub-zero temperature to reduce the Boolean-off rate (BOR).

Specifically, conventionally, the temperature of the cofferdams is always maintained at 5 ° C or higher, which is a reason why when the temperature of the cofferdams is controlled to be lower than 5 ° C, the bulkhead of the copper dam using the steel grade A specified by IGC (11) is lower than 0 ° C and there is a risk of brittle fracture.

As described above, when the temperature of the cofferdams is maintained at 5 ° C or higher, the BOR occurs due to the heat transfer due to the temperature difference between the cofferdams and the LNG stored in the LNG storage tank T. For example, , The BOR of 0.1282 is calculated as shown in the table of Fig.

However, when the temperature of the cofferdams 10 is controlled to a sub-zero temperature as in the present embodiment, the temperature difference between the LNG and the cofferdams 10 becomes small, and the heat transfer between the LNG and the cofferdams 10 is reduced , Which leads to a decrease in BOR.

7, when the temperature of the bulkhead 11 of the copper dam 10 is controlled to -25 캜, the temperature of the copper dam 10 can be maintained at -20.8 캜. In this case, BOR is 0.1236, which is reduced by 3.5% compared with the conventional BOR.

7, when the temperature of the bulkhead 11 of the copper dam 10 is controlled to -50 deg. C, the temperature of the copper dam 10 can be maintained at -46.5 deg. C, and in this case, the BOR Is 0.1192, which is 7.0% less than the conventional BOR. For reference, the numerical values of BOR mentioned above are the result of numerical analysis.

However, if the temperature of the cofferdam 10 is maintained at a subzero temperature, it is expected that the bulkhead 11 should be made of a material specified by the IGC or a low-temperature steel (LT), thereby increasing the cost. However, The increase is less than the benefit generated when the BOR is reduced, so the BOR can be efficiently reduced at a relatively low cost.

Also, the loss of LNG vaporized by the BOG can be prevented by the reduction of BOR, which can sufficiently offset the above-mentioned increase in cost.

As shown in Fig. 1, the coffer dam 10 in this embodiment includes a pair of bulkheads 10, which are spaced apart from each other between a plurality of LNG storage tanks T, And a space portion 12 provided by a pair of bulkheads 11 and an inner hull IH so that the temperature of the pair of bulkheads 11 is controlled at a subzero temperature, 10) can be controlled at a sub-zero temperature.

In this embodiment, the temperature of the copper dam 10 may be adjusted by, for example, adjusting the set temperature at which the heating system of the copper dam 10 operates or by installing the heat insulating material 120 (see FIG. 9) Gas can be injected into the coffer dam 10 and adjusted to a subzero temperature.

Specifically, when designing an LNG carrier, the LNG carrier should be designed to be free from problems even when the outside air temperature is -18 ° C and the seawater temperature is 0 ° C according to USCG conditions. If the cofferdams 10 are not heated under these external temperature conditions, the cofferdam 10 falls down to -60 캜 by the cooling of the LNG stored in the LNG storage tank T.

Therefore, conventionally, the temperature of the space portion 12 of the copper dam 10 is controlled at 5 ° C and the temperature of the bulkhead 11 is kept at 0 ° C or more by heating the copper dam 10.

However, in the present embodiment, unlike the conventional LNG carrier, the temperature of the cofferdam 10 can be adjusted to a sub-zero temperature by allowing the heating device to operate at a sub-zero temperature proposed in the present embodiment.

The coffer dam 10 may be controlled to a subzero temperature by providing a heat insulating material 120 (see FIG. 9) inside the coffer dam 10, and the heat insulating material 120 may be controlled in detail in the second embodiment Explain.

In the present embodiment, the above-described method of controlling the temperature of the copper dam 10 to a subzero temperature may be used independently or may be used as another method, so that the scope of the present invention is limited to the application of any one of the methods It does not.

Since the bulkhead 11 of the copper dam 10 is controlled to a subzero temperature, the bulkhead 11 is manufactured by the steel grades B, D, E, AH, DH, and EH specified by the IGC .

Particularly, when the bulkhead 11 of the coffer dam 10 is controlled at -30 to -20 占 폚, the bulkhead 11 can be manufactured with a steel grade E or EH specified by the IGC, Is controlled at -60 to -30 占 폚, the bulkhead 11 can be manufactured with a low temperature steel (LT).

In the present embodiment, when the bulkhead 11 is made of a low-temperature steel, the low-temperature steel is a low temperature carbon steel, a low temperature alloy steel, a nickel steel, an aluminum steel, an austenitic stainless steel Steel, or a combination of at least one of the above groups.

1 and 3, when the cofferdam 10 is arranged in one row in the width direction of the hull, the space portion 12 includes a pair of longitudinally spaced bulkheads 11 can form the front wall 7a and the rear wall 9a and the inner hull IH can form the left and right side walls, the ceiling portion and the bottom portion.

Furthermore, in this embodiment, as shown in Fig. 4, the coffer dam 10 includes a lateral coffer dam 10a for horizontally dividing the internal space of the LNG storage tank T, And a longitudinal copper dam 10b.

In this case, in the case of the transverse cofferdam 10a, the space portion 12 of the coffer dam 10 is constructed such that a pair of bulkheads 11 spaced apart from each other in the longitudinal direction of the hull, The inner hull IH can form the front wall and the rear wall of the inner hull IH and the inner hull IH can form the front wall and the rear wall of the inner hull IH, A ceiling wall and a bottom wall can be formed.

4, a pair of bulkheads 11 spaced apart from each other in the width direction of the hull can form the right and left walls of the space portion 12, respectively. In the case of the longitudinal cofferdam 10b, And the wall in which the bulkhead 11 of the longitudinal cofferdam 10b and the bulkhead 11 of the lateral cofferdam 10a abut can form the front wall 7a and the rear wall 7b, The inner hull IH can form a ceiling wall and a bottom wall.

The space portion 12 of the present embodiment may be provided with the heat insulating material 120 of the second embodiment to be described later and the heat insulating material 120 will be described in detail in the second embodiment.

The gas supply unit serves to prevent the coffer dam 10 from being damaged due to a change in humidity or the like when the coffer dam is supplied with gas into the coffer dam.

In this embodiment, the gas supply unit may be configured in the same manner as the gas supply unit 300 (see Fig. 17) of the fourth embodiment described later, and the gas branched from the gas supply line and supplied through the gas supply line is supplied to the copper dam A discharge piping provided in the coffer dam 10 for discharging the gas filled in the inside of the coffer dam 10 to the outside of the coffer dam 10 and a discharge piping provided in the supply piping and the discharge piping Valve.

The supply pipe of the gas supply unit may be provided in a number corresponding to the coffer dam 10 and the lower end of the supply pipe may be disposed close to the bottom of the coffer dam 10. [

The discharge piping of the gas supply unit may be provided in a number corresponding to the coffer dam 10 to discharge the gas filled in each of the cofferdam 10, or may be connected to and discharged from each other.

The valve of the gas supply unit 20 may be a proportional control valve that is opened or closed by an electrical signal.

In this embodiment, the gas supplied to the gas supply line includes dry air, inert gas or N ₂ gas, which is supplied to a conventional dry air / iner Gas generator.

Meanwhile, the present embodiment may include a heating unit 30 for controlling the temperature of the copper dam 10, which has fallen to the first temperature of the sub-zero temperature, to a second sub-zero temperature higher than the first temperature.

8, the heating unit 30 includes a cool-water heating coil 31 disposed inside the coffer dam 10, and a heated cool-coil (not shown) glycol may be supplied to heat the bulkhead 11 or an electric coil may be installed inside the coffer dam 10 to heat the bulkhead 11.

In addition, the bulkhead 11 may be heated by providing a coil in which waste heat of the exhaust gas or high temperature liquid or steam can be circulated in the inside of the coffer dam 10.

In the present embodiment, when a glycol is used as an antifreeze, 45% of glycol water having a freezing point of -30 ° C can be used.

A method of heating the glycol supplied to the copper dam 10 will be briefly described with reference to FIG.

The glycol circulated by the glycol circulation pump is heated by the high temperature steam supplied from the boiler or the like in the glycol heater GH before being supplied to the copper dam 10, and the heated glycol is heated by the glycol And supplied to the heating coil 31 to heat the bulkhead 11 and then circulate.

In this embodiment, the coffer dam 10 may be provided with a temperature sensor TS capable of measuring the temperature inside the coffer dam 10. When the temperature inside the coffer dam 10 is lower than the set value, The glycol can be supplied to the glycol heating coil 31 attached to the bulkhead 11 to raise or maintain the temperature of the bulkhead 11 and the space 12.

On the other hand, when the temperature of the bulkhead 11 is controlled to -50 캜 or less, the freezing point of the antifreeze may fall below -50 캜. Therefore, the antifreeze may use glycol water or methyl alcohol. The contents described in the embodiments can be applied as they are in other embodiments described later.

9 is a view schematically showing a state in which a thermal insulating material is provided in a copper dam in a thermal insulation system for a floating marine structure according to a second embodiment of the present invention, and FIG. 10 is a view showing a state in which a heat insulating material is provided in the "A" FIG. 11 is a perspective view schematically showing a state in which a heat insulating material is provided in the "B" region in FIG. 9, FIG. 12 is a modified embodiment of the heat insulating material provided in the "C" 13 is a table showing calculation results of BOR generated by controlling the temperature of the copper dam by the heat insulating material shown in FIG.

The thermal insulation system 100 of the floating structure according to the present embodiment controls the temperature of the copper dam 10 to a subzero temperature irrespective of the spatial environment such as the polar regions and the tropical regions or the temporal environment such as the season, A heat insulating material 120 provided in the copper dam 10 is provided.

As shown in FIG. 9, the heat insulating material 120 is provided in the coffer dam 10 so that when the floating floating structure is operated in an area having a high temperature or is operated in summer, heat enters the inside of the copper dam 10 So that the temperature of the copper dam 10 can be lowered to a desired temperature even when the external temperature is high.

Specifically, when the outside temperature is high, for example, when the temperature of the outside air indicated by the IGC code is 45 ° C and the seawater temperature is 25 ° C, when the heat insulating material 120 is not installed, Likewise, the temperature of the copper dam 10 may not fall only to -15.39 占 폚, which may limit the reduction of the BOR.

However, if the heat insulating material 120 is provided in the copper dam 10 as in the present embodiment, the temperature of the copper dam 10 can be lowered to a desired temperature, for example, -25 캜 and -50 캜, BOR reduction effect can be seen.

Now, the insulation material 120 will be described in detail. In the present embodiment, the thermal insulation material 120 is formed by taking into account the ease of operation and cost, as well as the heat insulation wall used for insulation of the LNG stored in the LNG storage tank T It is possible to use a different type of the above-mentioned insulating wall.

That is, in this embodiment, the heat insulating material 120 may include at least one of a panel type heat insulating material, a foam type heat insulating material, a vacuum heat insulating or particle type heat insulating material, and a nonwoven type heat insulating material different from the above- have.

In this embodiment, the heat insulating material 120 can be applied without limitation to types and shapes. Only one of the above three types of heat insulating materials may be used in consideration of work environment, cost, and the like, or two or more heat insulating materials may be selected and used. In addition, an insulating wall for inserting LNG stored in the LNG storage tank T may be used. Here, the heat insulating wall refers to the heat insulating wall of the sealing and heat insulating unit SI.

The panel-type heat insulating material includes styrofoam, and the styrofoam can be bonded to the copper dam 10 in an attaching manner by using a low-temperature adhesive or a bolt.

The foamed type heat insulating material includes a polyurethane foam, and the polyurethane foam can be injected and bonded to the copper dam 10 in a foaming manner.

The nonwoven fabric type heat insulating material may be made of a polyester fiber material, a synthetic resin layer, or may be bonded to the copper dam 10 using a low temperature adhesive or bolt.

In the present invention, there is no limitation as to the type and installation method of the heat insulating material 120.

In this embodiment, the heat insulating material 120 may be provided in the space portion 12 of the coffer dam 10 in the region excluding the pair of bulkheads 11, as shown in Fig.

10, in the case of the lateral direction cofferdam 10a, the heat insulating material 120 is provided on the right side wall portion, the left side wall portion, the ceiling portion and the bottom portion of the space portion 12 of the coffer dam 10, respectively . The heat insulating material 120 provided in the ceiling portion and the bottom portion may be provided outside the space 12 but outside.

When the heat insulating material 120 is provided on the copper dam 10 in the region excluding the pair of the bulkheads 11 as described above, the heat outside the regions not in contact with the pair of bulkheads 11 is transferred to the copper dam 10, The cold heat of the LNG stored in the LNG storage tank T can be transferred to the space portion 12 through the pair of bulkheads 11 so that the temperature outside the hull is high The temperature of the copper dam 10 can be lowered to a desired temperature.

In this embodiment, the heat insulating material 120 is formed of a forwardmost bulkhead 11 of the transverse cofferdam 10a disposed at the forwardmost one of the plurality of transverse cofferdam 10a, And also to the aft end bulkhead 11 of the coffer dam 10a.

Specifically, FIG. 11 shows that the heat insulating material 120 is provided on the bulkhead 11 at the foremost fore end, and the fore and aft end chambers have different environments from those between the fore and aft ends.

That is, since the LNG storage tank T is in contact with only one direction and is in contact with the inner wall of the hull, it is preferable that the lowering of the temperature of the cofferdam 10 to the desired temperature is performed in the region between the fore and aft It is harder than the copper dam 10.

However, as in the present embodiment, the heat insulating material 120 is also provided in the forefoot bulkhead 11 and the aft-end bulkhead 11, thereby preventing external heat from entering the cofferdam 10, .

On the other hand, when the heat insulating material 120 is installed inside the copper dam 10, the heat insulating material 120 provided at the bottom of the copper dam 10 may be damaged by the source of the water. That is, when the operator enters the inside of the cofferdam 10, the bottom of the coffer dam 10 must be supported by the feet, and the heat insulating material 120 may be damaged at this time.

Therefore, in this embodiment, as shown in Fig. 12, a heat insulating material damage preventing member can be provided to prevent the above-described heat insulating material 120 from being damaged.

In this embodiment, the heat insulating material damage preventing member 130a is provided in a grid form as shown in FIG. 12 (a) and disposed on the heat insulating material 120, so that a load is applied to a specific portion of the heat insulating material 120 So that the heat insulating material 120 can be prevented from being damaged.

The heat insulating material damage preventing member 130b may be a separate path provided at the bottom of the copper dam 10 so that the source can be moved to a desired location. Since the area where the crew approaches mainly is the bottom edge of the bottom portion, the heat insulating material damage preventing member 130b is provided with a slight width only at the bottom edge of the copper dam 10 as shown in FIG. 12 (b) .

Fig. 13 shows a reduction effect of the BOR by the installation of the heat insulating material and the temperature control of the coffer dam.

When the coffer dam is controlled at 5 캜 as in the conventional case, the BOR becomes about 0.1282. In this case, even if the control temperature of the glycol heating system is controlled to control the temperature of the copper dam, if the glycol heating is not performed, the copper dam may only drop to -10.87 ° C even at the lowest falling temperature.

Therefore, even if the bulkhead 11 of a copper dam is manufactured with a steel grade E that can be applied to -25 ° C, the temperature of the copper dam is only dropped to -15.39 ° C, so the BOR can be reduced by only about 2.2%.

However, the BOR can be reduced by about 3.5 by installing the heat insulating material 120 so that the cofferdam 10 falls to -26.4 캜 by applying the present embodiment and controlling the temperature to -20.8 캜 by glycol heating.

The contents of the first embodiment described above can be applied to the present embodiment as it is.

14 is a view schematically showing a state in which the bulkhead of the copper dam in the floating structure according to the third embodiment of the present invention is connected to the inner hull only without extending to the outer hull, and Fig. 14 in which a copper dam is provided in place of the head and a heat insulating material is provided in the copper dam. Fig. 16 is a view showing a modification of the BOR generated by making the bulkhead shown in Fig. 13 as a cryogenic material and controlling the temperature of the copper dam. Fig.

The insulation system 200 of the floating structure according to the present embodiment is provided between the plurality of LNG storage tanks T so that the plurality of LNG storage tanks T can be connected to at least one of the longitudinal direction and the width direction of the ship. A bulkhead 210 connected to the inner hull IH without being extended to the outer hull EH and a bulkhead 210 connected to the inner hull IH and the outer hull EH, And a space portion 12 provided by the bulkhead 210 at the fore and aft ends of the forward and aft end chambers 210 and 210, And a heating unit 30 for heating the bulkhead 210 provided at the forefront and aft end of the bow.

14, the bulkhead 210 may be arranged in multiple rows in the longitudinal direction of the hull, or may be arranged in multiple rows in the width direction of the hull.

In this embodiment, since the sealing and heat insulating unit SI and the heat insulating material 120 are not provided in the region where the bulkhead 210 and the LNG storage tank T are in contact with each other, the bulkhead 210 can be cryogenic The temperature may drop.

Therefore, in the present embodiment, the bulkhead 210 can be made of a cryogenic material including stainless steel or aluminum, and can be used as a seal for sealing and insulating the LNG storage tank T, May be welded directly to the bulkhead 210.

Further, a pair of the bulkheads 210 of this embodiment are provided at the forefront of the bow and at the rear end of the stern, so that the space 12 can be provided at the frontmost and the forefront of the bow. The bulkhead 210 of the space portion 12 may be provided with a heat insulating material 120 and a heating portion 30. To prevent the bulkhead 210 from being damaged by the space portion 12, Gas can be supplied.

On the other hand, the bulkhead 210 of the present embodiment does not extend to the outer hull EH, unlike the prior art, as shown in Fig. This is because when the bulkhead 210 is connected to the outer hull EH, external heat may be transmitted through the bulkhead 210 to increase the BOR and the external hull EH is in contact with the bulkhead 210 And the brittle fracture can be caused by the cold heat transmitted from the bulkhead 210.

The strength member 220 serves to structurally reinforce the hull by connecting the inner hull IH and the outer hull EH at an intermediate position of the LNG storage tank T as shown in Fig.

The strength member 220 of this embodiment is provided not to be continuous with the bulkhead 210 as shown in FIG. 14, so that the cold heat transmitted through the bulkhead 210 is provided at both ends of the bulkhead 210 It can be seen that the heat transfer from the outside is also reduced since the bulkhead 210 is not in direct contact with the outer hull EH.

The strength member 220 of this embodiment can be provided at any position on the position surface that is not continuous with the bulkhead 210, and the number of the strength member 220 is not limited.

Further, the strength member 220 is not exposed to a cryogenic temperature, so it may be made of steel of grade A as well.

The heat insulating material 120 of the second embodiment may be applied to the heat insulating material 120 as it is. However, there is a difference in that the LNG storage tank (T) is provided at the forwardmost position and the aft endmost position, not between the LNG storage tanks (T).

The gas supply unit and the heating unit 30 may be applied to the first embodiment as it is. However, this embodiment differs from the first embodiment in that it is applied to the space portion 12 provided at the fore and aft ends of the bow.

The present embodiment is characterized in that the bulkhead 210 is provided between the LNG storage tanks T and not the cofferdams 10 to directly control the temperature of the bulkhead 210 disposed between the LNG storage tanks T The bulkhead 210 described above is controlled to about -130 DEG C due to the direct contact of the LNG.

However, the bulkhead 210 disposed at the foremost part of the forward and the forefront of the athlete can be freely adjusted in temperature by the heating part 30, and the temperature of the bulkhead 210 disposed between the LNG storage tanks T The temperature of the bulkhead 210 can be controlled by regulating the heat insulating wall of the sealing and adiabatic unit SI or by heating both ends of the bulkhead 210 with an electric coil.

15, two or more of the bulkheads 210 may be provided, or two or more of the bulkheads 210 may be disposed apart from each other, and the inner hull IH ) And the outer hull (EH).

On the other hand, in this embodiment, as shown in Figs. 14 and 15, the sealing and heat insulating unit SI may not be provided in the region where the bulkhead 11 and the LNG storage tank T are in contact with each other. In this case, When the bulkhead 11 is made of a cryogenic material and the temperature of the copper dam 10 is controlled to a subzero temperature, a BOR as shown in Fig. 16 can be obtained.

14, if the sealing and heat insulating unit SI are not provided in the area where the bulkhead 11 and the LNG storage tank T are in contact with each other, the cold heat of the LNG stored in the LNG storage tank T The temperature of the copper dam 10 can be sufficiently transferred to the copper dam 10 to drop to -125 占 폚, as shown in Fig. At this time, it can be seen that the BOR is 0.1061, which is 17.2% lower than when the coffer dam 10 is controlled at 5 ° C.

In this case, the bulkhead 11 of the copper dam 10 is made of a cryogenic material including stainless steel or aluminum rather than a general material, and is sealed and sealed in contact with the bulkhead 11, Can be coupled to the bulkhead 11 in a welded manner.

FIG. 17 is a view schematically showing a gas supply unit in a floating structure according to a fourth embodiment of the present invention, and FIG. 18 is a diagram showing the calculation result of the BOR generated by controlling the temperature of the coffer dam shown in FIG. Table.

The floating structure 300 according to the present embodiment is provided between a plurality of LNG storage tanks T so that the plurality of LNG storage tanks T can be divided into a plurality of LNG storage tanks T in the longitudinal direction and / A gas supply unit 320 for supplying a gas to the coffer dam 10 and a gas supply unit 320 provided in the coffer dam 10 so that an operator can control the internal space of the cofferdam 10 A heating part 30 for heating the copper dam 10 so as to be able to enter the copper dam 10 and a heat insulating material 120 provided for the copper dam 10.

The present embodiment is different from the first embodiment in that it has a gas supply unit 320 for supplying gas into the inside of the copper dam 10 so as to easily find a cold spot formed in the bulkhead 11 of the copper dam 10 This is different from the first and second embodiments described above. The cofferdam 10, the heating unit 30, and the heat insulating material 120 described in the first and second embodiments described above can be applied as they are in the present embodiment.

In the floating structure of the present embodiment, the operator must periodically enter the coffer dam 10 to examine whether the bulkhead 11 of the coffer dam 10 has a cold spot. That is, it is necessary to check whether a cold part of the temperature has occurred in a specific part of the bulkhead 11 of the copper dam 10, and it is known that the bulkhead 11 is stuck and visually inspected.

However, when the temperature of the copper dam 10 is kept at a low temperature and the inside of the copper dam 10 is filled with ordinary air, the entire bulkhead 11 of the copper dam 10 becomes hot, I can not find a cold spot.

In this embodiment, the coffer dam 10 is filled with a gas such as dry air, and the temperature of the bulkhead 11 of the coffer dam 10 is controlled to be higher than the dew point of the dry air So that the cold spot can be easily found by putting the cast in only the bulkhead 11 lower than the dew point of the dry air.

For example, when the dew point temperature of the dry air generated in the LNG carrier is -40 ° C, the temperature of the bulkhead 11 of the coffer dam 10 is controlled to -35 ° C, , The cold head can be easily found at the position of the castle because the bulkhead 11 of the copper dam 10, which is lower than -40 ° C, is hot.

The technical means for supplying dry air having a low dew point temperature to the inside of the cofferdam 10 described above is the same as the description of the first embodiment in which the trunk deck space (TS, see Fig. 21) It can be applied as it is to the passage SP (see Fig. 21).

When the temperature of the bulkhead 11 of the copper dam 10 is controlled to -35 캜, as shown in the table of Fig. 18, the BOR can be reduced by about 4.9% as compared with the control at 5 캜. In this case, the bulkhead 11 can be made of low-temperature steel LT.

17, the gas supply unit 320 includes a gas supply unit (not shown) provided in the coffer dam 10 to supply a gas supplied through the gas supply line AL to the inside of the copper dam 10 A gas discharge pipe 322 provided in the coffer dam 10 for discharging the inner gas of the coffer dam 10 to the outside of the coffer dam 10 and a gas discharge pipe 322 for discharging the inner gas of the cofferdam 10 to the outside of the coffer dam 10, Closing valve 323 provided in the second chamber 322.

In this embodiment, the dry air supplied to the gas supply line (AL) can be supplied from a dry air generator installed in a conventional LNG carrier, so that no additional cost is incurred for this facility.

In this embodiment, the dry air supplied to the copper dam 10 may have a dew point temperature of -45 to -35 占 폚, and the temperature of the bulkhead 11 of the copper dam 10 may be set to be lower than the dew point temperature of the dry air by 1 ~ 10 ° C. In this case, since the temperature of the bulkhead 11 is controlled to about -30 캜, there is an advantage that the BOR can be reduced.

When personnel enter the copper dam 10 due to reasons such as inspection and maintenance, it is possible to prevent the low temperature and perform work by wearing clothes such as winter clothes. On the other hand, the above-mentioned gas is injected into the coffer dam 10 continuously and vented, thereby increasing the temperature of the cofferdams.

19 is a view schematically showing control of the temperature of the cofferdams according to the pressure change of the LNG storage tank in the floating structure according to the fifth embodiment of the present invention.

The insulation system 400 of the floating structure according to the present embodiment is provided between the plurality of LNG storage tanks T so that the plurality of LNG storage tanks T can be installed in at least one of the longitudinal direction and the width direction of the ship And a heating unit 30 provided in the coffer dam 10 to heat the coffer dam 10. The temperature of the coffer dam 10 is set to a subzero temperature of the coffer dam 10, Is different from the first embodiment in that it controls the temperature of the cofferdam 10 in accordance with the change of the internal pressure of the LNG storage tank T and is controlled by the temperature of the heating furnace image of the heating unit 30 And the remaining contents of the first embodiment can be directly applied to this embodiment.

That is, in this embodiment, in order to lower the BOR, the temperature of the cofferdams 10 is maintained at a sub-zero temperature, and when the BOG is too small according to the voyage condition, 10) to increase the BOR so as to generate more BOG, and if the BOG is too much generated due to the voyage conditions and the BOG treatment is difficult, the temperature of the cofferdams 10 is lowered to make the BOR smaller BOG can be generated a little more.

The control temperature may be set manually in consideration of the voyage conditions, etc., or may be automatically controlled by receiving a pressure signal from the LNG storage tank T. That is, when the pressure of the LNG storage tank T is high, since the BOG is excessively generated, control is performed so as to lower the set value of the control temperature. When the pressure is low, BOG is slightly generated. .

In this embodiment, in order to lower the BOR, the temperature of the copper dam 10 is maintained at a subzero temperature, and the temperature of the copper dam 10 is set to a specific temperature (for example, , The temperature of the image), which is different from the first embodiment described above.

Specifically, it is necessary for the operator to enter the inside of the cofferdam 10 to check whether or not a cold spot or the like is generated in the cofferdam 10 during the operation.

At this time, if the cofferdam 10 is maintained at a subzero temperature, a worker entering the coffer dam 10 may be exposed to a low temperature and become dangerous. Therefore, the setting value of the control temperature is raised, The temperature of the copper dam 10 can be maintained at a specific temperature (for example, the temperature of the image) by heating the copper dam 10.

In the present embodiment, when the bulkhead 11 of the copper dam 10 is made of a material that can withstand temperatures of -30 to 0 占 폚, the temperature of the copper dam 10 can be controlled within a range of -30 to 70 占 폚. For example, when the operator does not need to enter the inside of the cofferdam 10, the control temperature of the coffer dam 10 can be controlled to about -30 ° C. in order to reduce the BOR as much as possible, 10) can be controlled to a specific temperature including the temperature of the image.

In the present embodiment, when the bulkhead 11 of the copper dam 10 is made of a low-temperature steel (LT) capable of withstanding -55 占 폚, the temperature of the copper dam 10 is controlled within a range of -55 to 70 占can do. For example, when the operator does not need to enter the inside of the cofferdam 10, the temperature of the cofferdam 10 can be controlled to about -50 ° C. in order to reduce the BOR as much as possible, and in the opposite case, ) Can be controlled to a specific temperature including the temperature of the image.

Hereinafter, a method of controlling the temperature of the copper dam to enter the inside of the copper dam 10 will be described.

First, the temperature of the cofferdam 10 is controlled to a sub-zero temperature, for example, -25 ° C. or -50 ° C. to reduce the heat transfer between the cofferdam 10 and the LNG stored in the LNG storage tank T, It is dangerous to go directly into the inside of the Copper Dam.

Therefore, the step of heating the coffer dam 10 to the temperature of the image is performed by the heating unit 30. At this time, the coffer dam 10 may be heated by a glycol heating coil 31, an electric coil, steam, or a coil through which fresh water flows, and may be heated by supplying hot air into the inside of the coffer dam 30.

Next, when the internal temperature of the cofferdam 10 reaches the image temperature, an operator enters and checks whether or not a cold spot or the like is generated in the bulkhead 11. At this time, the inside of the copper dam 10 is maintained at the temperature of the image continuously.

When the operator completes the internal inspection of the copper dam 10 and exits the copper dam 10, the heating of the copper dam 10 is stopped, and the copper dam 10 is maintained at a zero temperature again.

As described above, the present embodiment can reduce the BOR by keeping the coffer dam 10 at a sub-zero temperature when the operator does not need to enter the inside of the coffer dam 10, and in the opposite case, the coffer dam 10 ) Can be maintained at the temperature of the image so that the operator can perform the work, and the safety of the operator can be considered while reducing the BOR.

The technical means for controlling the temperature of the cofferdam 10 described above is the same as that of the sixth embodiment described later with reference to the trunk deck space TS (see FIG. 21) and the side passage SP ).

The present embodiment is different from the first embodiment in that the temperature of the coffer dam 10 can be controlled in accordance with a change in the internal pressure of the LNG storage tank T.

Specifically, in this embodiment, a pressure sensor PT capable of measuring the internal pressure of the LNG storage tank T is provided in the LNG storage tank T as shown in FIG. 19, The temperature of the copper dam 10 can be controlled on the basis of the pressure measured in the coffer dam 10.

That is, when the pressure of the LNG storage tank T is increased, BOG is generated more than the BOG required for the floating structure, so that the setting temperature of the cofferdam 10 temperature control is lowered, ) Can be lowered to reduce the BOG. When the pressure of the LNG storage tank (T) is lowered, BOG is generated less than the BOG required for the floating structure. Therefore, by raising the temperature of the cofferdam (10) by raising the setting temperature of the cofferdam BOG can be generated more.

In addition, the temperature of the copper dam 10 can be controlled with reference to the speed of the floating structure regardless of the pressure sensor PT.

Specifically, if the speed of the floating structure is high and the fuel consumption is large, the control temperature of the coffer dam 10 may be increased to generate more BOG, and the generated BOG may be used as fuel to adjust the fuel consumption amount.

For example, a floating structure that controls the bulkhead 11 of the copper dam 10 at a setting temperature of -25 占 폚 has a BOR of 0.1236. Controlling the temperature of the bulkhead 11 of the cofferdam 10 at 0 ° C increases the BOR to 0.1282 and increases 3.7% to increase the BOG when the floating structure is to increase the speed and consume more fuel. Therefore, it is possible to reduce the amount of BOG when the consumption of the BOG is increased due to the increase of the speed of the floating sea structure.

On the other hand, when the speed of the floating floating structure is low and the fuel consumption is small, the control temperature of the coffer dam 10 may be lowered to generate a small amount of BOG so that the fuel consumption can be adjusted.

On the other hand, when the bulkhead 11 of the coffer dam 10 is heated by the heating unit 30, heat is transferred by conduction and a heating time of the copper dam 10 may take a long time. It is also possible to shorten the heating time of the cofferdam 10 by supplying warm dry air.

In addition, the gas supply unit and the gas supply unit 320 described in the above embodiments can be applied as they are in this embodiment.

20 is a view schematically showing a state in which a heat insulating material is provided in a trunk deck space TS and a side passage in a thermal insulation system of a floating marine structure according to a sixth embodiment of the present invention, And the calculation result of the BOR generated by controlling the temperature of the inner hull (IH) in contact with the trunk deck space (TS) and the side passage.

The thermal insulation system 500 of the floating structure according to the present embodiment is provided in at least one of a trunk deck space and a trunk deck TD in a side passage way A heat insulating material 120 for reducing heat cutting from the trunk deck space TS or the side passages SP to the inside of the plurality of LNG storage tanks T to reduce the BOR generated by heat transfer do.

The present embodiment can lower the BOR by reducing the amount of heat penetration from the outside by lowering the temperature of the inner hull IH in contact with the trunk deck space TS and the side passages SP.

Particularly, when the navigation system is operated in the vicinity of the Arctic route or in the winter, the temperature of the inner hull (IH) in contact with the trunk deck space (TS) and the side passageway (SP) The BOR can be reduced.

The temperature of the inner hull IH in contact with the trunk deck space TS and the side passages SP is lowered by the heat insulating material 120 even in the case of sailing to a place where the temperature is high, Can be kept at a low temperature, and the BOR can be reduced.

Particularly, since the side passage (SP) in contact with the trunk deck (TD) and the trunk deck (TD) is directly exposed to the external solar heat, the heat insulating material 210 is provided in this portion, Can be reduced more effectively.

As shown in the table of FIG. 21, when the temperature of the inner hull (IH) in contact with the trunk deck space (TS) and the side passage (SP) is not controlled as a result of numerical analysis of the actual LNG carriers, The temperature of the inner hull (IH) is about 35.3 ° C, and the BOR is calculated as 0.1346.

However, when the temperature of the inner hull IH in contact with the trunk deck space TS and the side passages SP is controlled to 0 占 폚 by applying the present embodiment, as shown in the table of Fig. 21, the BOR is 0.1296 Which is about 3.7% lower than that of the conventional method. It can be seen that the BOR can be reduced by using the low-cost heat insulating material 120 and the BOR reduction effect on the price is large.

As another example, when the temperature of the inner hull (IH) in contact with the trunk deck space (TS) and the side passage (SP) is controlled to -25 ° C by applying the present embodiment, it is confirmed that the BOR is reduced by about 5.9% there was. It can also be seen that the use of the low-cost insulating material 120 has a large BOR reduction effect on the price.

20, the heat insulating material 120 includes an inner ceiling portion of the trunk deck TD, a ceiling portion and a side wall portion of the side passage SP contacting the trunk deck TD, a side passage portion contacting the ballast tank BT, (SP).

The heat insulating material 20 is not limited to the position of the trunk deck TD and may be provided on the bottom or the outer side of the trunk deck TD and may be provided in the trunk deck space TS and the side passage SP Or may be provided continuously or intermittently.

In this embodiment, the heat insulating material 120 of the above-described embodiment can be applied as it is. In other words, the heat insulating material 120 of the present embodiment may be a heat insulating wall of a sealing and heat insulating unit SI for sealing and insulating the LNG storage tank T, a panel type heat insulating material different from the heat insulating wall, , A vacuum insulating or particle type insulating material, and a nonwoven type insulating material. Further, the present invention is not limited to the kind, shape and installation method of the heat insulating material.

The present embodiment may have a heating portion 30 for heating the inner hull IH to heat the cofferdam 10 or to maintain the inner hull IH at a desired temperature. The configuration of the heating unit 30 may include a coiled heating coil 31 of the above-described embodiment, an electric coil, a coil through which liquid such as steam or fresh water flows, and the like.

In this embodiment, the material and temperature of the inner hull IH in contact with the trunk deck space TS and the side passages SP can be selectively adjusted according to the value of the required BOR.

Specifically, in this embodiment, the inner hull IH can be controlled at a temperature of -55 to 30 占 폚. When the temperature of the inner hull IH is controlled at 0 캜, as shown in the table of Fig. 21, 0.1296 in which the BOR is reduced by 3.7% is obtained compared with the conventional example in which the inner hull IH is controlled at 35.3 캜 , And the inner hull (IH) can also use the steel grade A.

If the temperature of the inner hull IH is controlled to -25 캜, as shown in the table of Fig. 21, 0.1266 in which the BOR is reduced by 5.9% can be obtained and the inner hull IH can be used with the steel grade E or EH . Further, when the temperature of the inner hull IH is controlled to -30 캜 or lower, the inner hull IH can be manufactured as a low temperature steel LT.

In the present embodiment, the contents of the cofferdam 10, the gas supply unit 320, and the gas supply unit of the above-described embodiments can be applied as they are.

FIG. 22 is a view schematically showing a state in which a thermal insulating material is provided in a ballast tank in a thermal insulation system for a floating marine structure according to a seventh embodiment of the present invention, and FIG. 23 is a graph showing the temperature of the inner hull IH contacting the ballast tank Table 1 shows the calculation results of the BOR generated by the control.

The insulation system 600 of the floating structure according to the present embodiment is provided with a thermal insulation material 600 provided in the ballast tank BT to reduce the BOR by reducing the heat transfer from the ballast tank BT to the inside of the LNG storage tank T 120).

The present embodiment can lower the BOR by reducing the amount of heat penetration from the outside by lowering the temperature of the inner hull IH in contact with the LNG storage tank T in the ballast tank BT.

The BOR can be reduced by lowering the temperature of the inner hull (IH) in contact with the LNG storage tank (T) in the ballast tank (BT) by the heat insulating material (120) when traveling at a high temperature or in the summer.

When the temperature of the inner hull (IH) in contact with the LNG storage tank (T) is not controlled in the ballast tank (BT) as a result of numerical analysis of the actual LNG carrier by the numerical analysis, , The temperature of this part is 27.2 ~ 36.13 ℃, and the BOR is calculated as 0.1346.

However, when the temperature of the inner hull IH in contact with the LNG storage tank T in the ballast tank BT is controlled to 0 캜 by applying the present embodiment, as shown in the table of Fig. 23, the BOR is 0.1242 Which is about 7.7%. That is, since the BOR can be reduced by taking the cost of the low-cost insulating material 120, it can be seen that the BOR reduction effect is large.

As another example, when the temperature of the inner hull (IH) in contact with the LNG storage tank (T) in the ballast tank (BT) is controlled to 5 ° C, the BOR is reduced to about 0.1262 by about 6.2%. It can also be seen that the use of the low-cost insulating material 120 has a large BOR reduction effect on the price.

The heat insulating material 120 may be provided on the inner side of the outer hull EH and on the ballast tank BT barrier in the region where the ballast tank BT and the site passage are in contact with each other as shown in Fig.

In this embodiment, the heat insulating material 120 of the above-described embodiment can be applied as it is. In other words, the heat insulating material 120 of the present embodiment may be a heat insulating wall of the sealing and heat insulating unit SI for sealing and insulating the LNG storage tank T, or a panel type heat insulating material of a type different from that of the heat insulating wall, A heat insulating material, a vacuum insulating or particle type insulating material, and a nonwoven type insulating material. Furthermore, the present invention is not limited to the kind, form and installation method of the heat insulating material.

The present embodiment may have a heating unit 30 for heating the inner hull IH to heat the cofferdam 10 or maintain the inner hull IH in contact with the ballast tank BT at a desired temperature. The configuration of the heating unit 30 may include a clear heating coil 31 of the above-described embodiment, an electric coil, steam or a fluid coil through which clean water flows.

In this embodiment, the material and temperature of the inner hull (IH) in contact with the ballast tank (BT) can be selectively adjusted according to the required BOR value.

Specifically, in this embodiment, the inner hull IH in contact with the ballast tank BT can be controlled at a temperature of -55 to 30 占 폚. When the temperature of the inner hull IH is controlled to 0 캜, as shown in the table of Fig. 23, the BOR is reduced by 7.7% from the previous embodiment in which the inner hull IH is controlled at 27.1 to 36.1 캜, And the inner hull (IH) can also be made of steel grade A.

When the temperature of the inner hull IH is controlled to 5 캜, 0.1262 in which the BOR is reduced by 6.2% can be obtained as shown in the table of Fig. 23, and the inner hull IH can use the steel grade A .

In the present embodiment, the contents of the cofferdam 10 and the gas supply unit 320 of the above-described embodiments can be applied as they are. However, the gas supply unit 320 can not be applied to the ballast tank BT when the ballast water is filled, so that it can be applied only to the coffer dam 10.

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 or scope of the invention. Accordingly, such modifications or variations are intended to fall within the scope of the appended claims.

1,200,300,400: Floating structures
100,500,600: Insulation system of floating structure
10: copper dam 30: heating part
120: Insulation 220: Strength member
320:

Claims (13)

A coffer dam disposed between a plurality of LNG storage tanks installed in one or more rows in the longitudinal direction of the hull; And
And a heating unit provided in the coffer dam to heat the coffer dam,
Wherein the cofferdams are controlled at a sub-zero temperature to reduce a boil-off rate (BOR) generated by heat transfer from the cofferdams to the inside of the plurality of LNG storage tanks, wherein the sub- And the temperature is changed to a specific temperature including the temperature. The method according to claim 1,
Wherein the cofferd dam comprises:
A pair of bulkheads spaced apart from each other between the plurality of LNG storage tanks; And
And a space portion provided by the pair of bulkheads and the inner wall of the hull,
Wherein the temperature of the sub-tank is lowered to a specific temperature including a temperature of the image by heating the pair of bulkheads with the heating unit. The method according to claim 1,
Wherein when the bulkhead of the copper dam is made of a material capable of withstanding from -30 to 0 占 폚, the copper dam is thermally deformed in a range of -30 to 70 占 폚. The method according to claim 1,
Wherein when the bulkhead of the copper dam is made of low temperature steel capable of withstanding up to -55 占 폚, the copper dam is thermally changed in a range of -55 to 70 占 폚. The method according to claim 1,
When the fuel consumption of the floating offshore structure is large, the temperature of the cofferdams is increased to increase the generation of boil-off gas (BOG)
Wherein when the fuel consumption of the offshore structure is small, the temperature of the cofferdams is lowered to reduce the occurrence of the BOG. The method according to claim 1,
Wherein the coffer dam is heated by the heating unit so that an operator can enter the inside of the coffer dam, and the temperature of the coffer dam is controlled to a specific temperature including an image. The method according to claim 1,
Wherein the freezing temperature of the cofferdam is changed to a specific temperature including the temperature of the image by the hot dry air supplied to the inside of the copper dam. The method according to claim 1,
When the internal pressure of the LNG storage tank is higher than the set pressure of the LNG storage tank, the set temperature of the cofferdam is lowered,
Wherein the set temperature of the coffer dam is increased when the internal pressure of the LNG storage tank is less than the set pressure of the LNG storage tank. The method according to claim 1,
Wherein the heating unit heats at least one of a trunk deck space controlled to a subzero temperature and a side passage way tangled with a trunk deck to control the trunk deck space and the side passage And the temperature of the floating structure is changed to a specific temperature including the temperature. The method according to claim 1,
Wherein the floating structure is any one selected from the group consisting of LNG FPSO, LNG FSRU, LNG carrier, and LNG RV. (BOR) generated by heat transfer from the cofferdams to the inside of the plurality of LNG storage tanks is reduced by controlling the cofferdams provided between the plurality of LNG storage tanks to a sub-zero temperature, Wherein the temperature is changed by heating of the heating part provided on the hull, and the temperature is maintained at a specific temperature including the temperature of the image. Controlling the cofferdams to a sub-zero temperature to reduce the BOR;
Controlling the coffer dam to a specific temperature including the temperature of the image so that the operator enters the cofferdam controlled by the subzero temperature; And
And controlling the cofferdams to a specific temperature of sub-zero when the operator exits the cofferdams. The method of claim 12,
Wherein the coffer dam is controlled in a temperature range of -55 to 70 占 폚.

Images