KR20210070163A - liquefied gas tank, gas treatment system and ship having the same - Google Patents

Abstract

The present invention relates to a liquefied gas storage tank, a gas treatment system and a vessel including the same. The liquefied gas storage tank forms a storage space storing liquefied gas by being surrounded by a wall including a primary protection wall of a metal material, a primary insulation wall placed outside the primary protection wall, a secondary protection wall provided outside the primary insulation wall, and a secondary insulation wall placed outside the secondary protection wall, wherein a primary insulation space including the primary insulation wall is formed between the primary and secondary protection walls, and a secondary insulation space including the secondary insulation wall is formed outside the secondary protection wall, and has a dome provided on the wall, which constitutes an upper side of the storage space, to be penetrated by a liquefied gas line for the inflow/discharge of liquefied gas. The dome includes: a dome cover penetrated by the liquefied gas line; and a dome coaming provided on the wall of the upper side of the storage space, in which the dome cover is placed and fixed, and finishing the primary and secondary insulation spaces, wherein the dome cover includes the liquefied gas line as well as a boil-off gas discharge line for the discharge of boil-off gas produced in the storage space, thereby being provided as a hybrid dome for introducing and discharging both liquefied gas and boil-off gas. Therefore, the present invention is capable of enabling efficient insulation space management.

Description

Liquefied gas storage tank, gas treatment system, and a ship including the same {liquefied gas tank, gas treatment system and ship having the same}

The present invention relates to a liquefied gas storage tank, a gas processing system, and a ship including the same.

According to recent technology development, liquefied gas such as liquefied natural gas (LNG) and liquefied petroleum gas (LPG) is widely used to replace gasoline or diesel.

LNG in ships that transport or store liquefied gas such as LNG at sea, LNG RV (Regasification Vessel), LNG FPSO (Floating, Production, Storage and Offloading), and LNG FSRU (Floating Storage and Regasification Unit) A liquefied gas storage tank (referred to as a "cargo hold") is installed for storing the liquefied gas in a cryogenic liquid state.

The liquefied gas storage tank can generate boil-off gas (BOG) by heat intrusion from the outside, and lowers the natural vaporization rate (BOR), which is the vaporization rate of boil-off gas, through an adiabatic design. This is the core technology of the design of the liquefied gas storage tank.

Accordingly, such a liquefied gas storage tank may have at least two layers of insulation space, and an Interbarrier Space (IBS) and an Insulation Space (IS) are provided in the outward direction based on the space in which the LNG is stored.

In addition, a dome is formed on the upper surface of the liquefied gas storage tank for loading/unloading of LNG, etc., and this dome includes a liquid dome for processing liquefied gas, and natural vaporization in the liquefied gas storage tank. A gas dome for the treatment of boil-off gas is provided, respectively.

At this time, a structure for securing safety by supplying inert gas or nitrogen gas to IBS and IS can be applied to the dome, and continuous research and development are made in the efficient arrangement of the dome insulation structure and nitrogen gas supply line. have.

The present invention was created to solve the problems of the prior art as described above, and an object of the present invention is to provide a dome for integrated processing of liquefied gas and boil-off gas, and to implement nitrogen flow in an adiabatic space using the dome. To provide a liquefied gas storage tank, a gas processing system, and a ship including the same.

A gas processing system according to an aspect of the present invention includes a metal primary barrier, a primary insulating wall disposed outside the primary barrier, and a secondary barrier provided outside the primary insulating wall; A storage space for accommodating liquefied gas is formed by being surrounded by a wall including a secondary thermal insulation wall disposed outside the secondary barrier, and including the primary thermal insulation wall between the primary barrier and the secondary barrier. Forming a secondary insulating space, forming a secondary insulating space including the secondary insulating wall on the outside of the secondary barrier, a liquefied gas line for the inflow and outflow of liquefied gas to the wall constituting the upper surface of the storage space It has a dome provided to pass through, the dome, the dome cover through which the liquefied gas line passes; and a dome coaming provided on the upper wall of the storage space, the dome cover being seated and fixed, and closing the primary insulating space and the secondary insulating space, the storage space with the liquefied gas line on the dome cover. It is characterized in that it is provided as a composite dome through which both liquefied gas and BOG are flown in and out by providing a BOG discharge line for discharging BOG generated inside.

Specifically, the dome cover may be provided so that a liquefied gas discharge line and a liquefied gas loading line for inflow and outflow of liquefied gas, and a boil-off gas discharge line for discharging BOG pass through.

Specifically, the dome cover is arranged such that at least a pair of the liquefied gas discharge line and the liquefied gas loading line form a triangle, and the boil-off gas discharge line is a triangle formed by the liquefied gas discharge line and the liquefied gas loading line may be disposed on the outside of

Specifically, the boil-off gas discharge line may be disposed adjacent to the liquefied gas loading line.

A ship according to an aspect of the present invention is characterized in that it has the liquefied gas storage tank.

A liquefied gas storage tank, a gas treatment system, and a ship including the same according to the present invention have a dome to process both liquefied gas and boil-off gas, and provide a line through which nitrogen flows in the dome to implement efficient insulation space management. have.

1 is a perspective view of a liquefied gas storage tank according to an embodiment of the present invention.
2 to 4 are perspective views of a dome cover of a composite dome according to an embodiment of the present invention.
5 is a plan view of a composite dome according to an embodiment of the present invention.
6 is a partial cross-sectional view of a composite dome according to an embodiment of the present invention.
7 is a partial perspective view of a composite dome according to an embodiment of the present invention.
8 is a plan view of a dome coaming of a composite dome according to an embodiment of the present invention.
9 to 11 are side views of a dome coaming of a composite dome according to an embodiment of the present invention.
12-19 are partial cross-sectional views of a dome coaming of a composite dome in accordance with an embodiment of the present invention.
20 is a conceptual diagram of a gas processing system according to an embodiment of the present invention.

The objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments taken in conjunction with the accompanying drawings. In the present specification, in adding reference numbers to the components of each drawing, it should be noted that only the same components are given the same number as possible even though they are indicated on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. For reference, although liquefied gas is described as meaning LNG in this specification, it is forced to liquefy for storage due to a lower boiling point than room temperature, and may encompass all substances (LPG, ethane, ammonia, etc.) having a calorific value. In addition, it should be noted that liquefied gas/evaporated gas in the present specification is not necessarily limited to liquid or gaseous due to the name.

The present invention includes a ship equipped with a liquefied gas storage tank and a gas treatment system to be described below. At this time, the ship may be a ship that uses at least liquefied gas as a propulsion fuel/power generation fuel, and it is a concept that includes all gas carriers, merchant ships that transport cargo or people other than gas, FSRUs, FPSOs, bunkering vessels, and offshore plants. .

1 is a perspective view of a liquefied gas storage tank according to an embodiment of the present invention, FIGS. 2 to 4 are perspective views of a dome cover of a composite dome according to an embodiment of the present invention, and FIG. 5 is an embodiment of the present invention A plan view of a composite dome according to an example. Here, FIGS. 2 and 3 correspond to a case in which the dome cover of the same composite dome is shown at different angles.

In addition, Figure 6 is a partial cross-sectional view of the composite dome according to an embodiment of the present invention, Figure 7 is a partial perspective view of the composite dome according to an embodiment of the present invention, Figure 8 is a dome of the composite dome according to an embodiment of the present invention It is a plan view of the coaming.

Also, FIGS. 9 to 11 are side views of a dome coaming of a composite dome according to an embodiment of the present invention, and FIGS. 12 to 19 are partial cross-sectional views of a dome coaming of a composite dome according to an embodiment of the present invention, and FIG. 20 is a conceptual diagram of a gas processing system according to an embodiment of the present invention.

For reference, the left and right directions of the cross-sectional structures of FIGS. 12 to 19 are for convenience of description, and it should be noted that the arrangement of each line is not limitedly interpreted due to the left and right directions in the drawings.

1 to 19 , the liquefied gas storage tank 100 according to an embodiment of the present invention is formed of a wall 110 . The wall 110 may form the storage space 11 by including the front, rear, left and right side surfaces and the lower surface and the upper surface.

At this time, the wall 110 may have a heat insulating structure to maintain the liquefied gas in a cryogenic liquid state. Specifically, as shown in FIGS. 12 to 19 , the wall 110 includes a first barrier 111 made of a metal forming a storage space 11 for accommodating liquefied gas, and the first barrier 111 . A primary insulating wall 112 disposed on the outside and made of polyurethane, etc., a secondary barrier 113 provided on the outside of the primary insulating wall 112 and made of a metal or a composite material, and a secondary barrier 113 It may include a secondary insulation wall 114 that is disposed on the outside of the hull and is made of polyurethane, etc., and is fixed to the hull.

Of course, in the present invention, the insulation structure of the wall 110 is not limited to the above structure, and any structure that does not allow leakage while being able to store liquefied gas at a low temperature may be used.

The primary barrier 111 and the secondary barrier 113 each function as a barrier for preventing leakage of liquefied gas. Therefore, the storage space 11 may be formed as a closed space by the primary barrier 111 (except for the compound dome 10 to be described later), and the secondary barrier 113 is a space closed outside the storage space 11 . can form. In addition, the hull also forms a closed space on the outside of the secondary barrier (113).

In this case, the closed space between the primary barrier 111 and the secondary barrier 113 may be referred to as the primary insulating space 12 . In addition, between the secondary barrier 113 and the hull on which the liquefied gas storage tank 100 is mounted (outside the secondary barrier 113) is referred to as a secondary insulating space (13).

The primary insulating wall 112 and the secondary insulating wall 114 may be filled in the primary insulating space 12 and the secondary insulating space 13, respectively, but the primary insulating wall 112 and the secondary insulating wall The wall 114 may have a foam structure such as an open cell for insulation, but may not have a structure that blocks gas or the like.

Therefore, the primary insulating space 12 and the secondary insulating space 13 are to be provided as spaces in which gas can flow despite the existence of the primary insulating wall 112 / secondary insulating wall 114 . can In this case, the primary insulating space 12 may be referred to as IBS, and the secondary insulating space 13 may be referred to as IS.

The primary insulating space 12 and the secondary insulating space 13 may be maintained at a preset internal pressure, and an inert gas such as nitrogen (N2) or inert gas (IG) may be used. For example, the inert gas may be injected into the primary thermal insulation space 12, etc. to increase the internal pressure of the primary thermal insulation space 12, and the inert gas may be discharged from the primary thermal insulation space 12 to the primary thermal insulation space 12. can lower the internal pressure.

In addition, by analyzing the inert gas discharged from the primary insulating space 12, if liquefied gas is mixed, it is determined that a leak has occurred in the primary barrier 111 or secondary barrier 113, and repair work is performed to solve the problem. can be solved

In addition, when the internal pressure in the primary insulating space 12 or the secondary insulating space 13 is placed above the preset pressure to such an extent that it is difficult to solve it only with the general discharge of the inert gas, 1 through the safety vent lines 24a and 24b It is also possible to urgently discharge the gas filled in the insulating space 12 / secondary insulating space (13).

The content of the internal pressure control of the insulating spaces 12 and 13 will be described in detail below with reference to FIG. 20 and the like. On the other hand, FIG. 20 is mainly for explaining the arrangement of each line, and FIG. 8 and the like are mainly for explaining the structure, and although the arrangement of FIG. 20 may be partially different from that of FIG. 8, this is variously modified according to the actual area and space. It is implied that this is possible, and the present invention may encompass all forms shown in the drawings.

Among the walls 110 constituting the liquefied gas storage tank 100, the wall 110 constituting the upper surface of the storage space 11 is provided with an opening 115 for the inflow and outflow of the liquefied gas, and the opening 115 has a dome 10 ) can be installed. At this time, the dome 10 is provided so that the liquefied gas lines 430, 431, 440, and 441 for the inflow or discharge of the liquefied gas pass through.

A protrusion 116 may be provided around the opening 115 in the upper wall 110 for installation of the dome 10 . The protrusion 116 may be bent vertically from the horizontal upper wall 110 to have a certain height upward, and the height of the protrusion 116 is a trunk deck (not shown) in which the upper surface of the dome 10 is provided on the hull. ), etc., may be made at a height that can be exposed upwards.

The protrusion 116 may be omitted. That is, the opening 115 is formed in the upper wall 110 , and the dome coaming 300 to be described later may be directly provided in the opening 115 . This may vary depending on the shape of the hull on which the liquefied gas storage tank 100 is mounted.

The dome 10 of this embodiment may be provided for the inflow and outflow of the liquefied gas stored in the liquefied gas storage tank 100 . At this time, as shown in FIG. 1 , the dome 10 may include a dome coaming 300 and a dome cover 400 .

The dome coaming 300 is provided on the upper wall 110 of the storage space 11 (the protrusion 116 when the protrusion 116 is provided), the dome cover 400 is seated and fixed, and the primary insulating space (12) and the secondary insulation space (13) is closed.

The primary insulating space 12 and the secondary insulating space 13 provided in the wall 110 may be opened upward in a state in which the dome coaming 300 is not installed. At this time, the dome coaming 300 is installed in the liquefied gas storage tank 100 while sealing the space between the primary barrier 111 and the secondary barrier 113 and the space between the secondary barrier 113 and the hull, respectively.

The dome coaming 300 may be provided in the form of a hollow polygonal column as shown in FIG. 8 . For example, the dome coaming 300 may be provided in the form of a square pillar. The dome coaming 300 may be configured to increase or decrease the internal pressure of the insulating spaces 12 and 13, respectively, on one side and the other side.

For example, the dome coaming 300 is provided such that an inert gas supply line 22 for increasing the internal pressure of the insulating space 12 and 13 by supplying an inert gas into the insulating spaces 12 and 13 on one side passes through, the other side side An inert gas discharge line for discharging the inert gas in the insulation space (12, 13) to lower the internal pressure of the insulation space (12, 13) may be penetrated.

In particular, this embodiment will be described later, but the dome 10 may be provided as a composite dome 10 that allows the discharge (and inflow) of boil-off gas as well as the inflow and outflow of liquefied gas.

In contrast to the case in which domes 10 corresponding to liquefied gas and boil-off gas are separately provided, the inert gas supply line 22 in the liquefied gas dome, and the inert gas discharge line in the boil-off gas dome, this embodiment allows both the inflow and outflow of liquefied gas/evaporated gas through one complex dome 10, so that the structure can be innovatively simplified, heat penetration into the storage space 11 can be greatly reduced, and there is a risk of liquefied gas leakage area can be minimized.

In addition, the present invention implements both the supply/discharge of inert gas to the insulating spaces 12 and 13 through one complex dome 10, but the supply of inert gas and the discharge of inert gas are performed on one side of the complex dome (10). and the other side opposite to it, it is possible to maintain a constant and stable pressure in the insulating space (12, 13).

A specific cross-sectional structure of the dome coaming 300 will be described with reference to FIGS. 12 to 19 . Referring to FIG. 12 and the like, the dome coaming 300 may include an outer wall 310 , an upper wall 320 , a support 330 , and a step removing means 340 .

The outer wall 310 is provided to have a predetermined height above the storage space 11 . The outer wall 310 may be provided parallel to the outer surface of the protrusion 116 and may be integrally fixed with the hull. It is also possible that a portion of the hull is provided to replace the outer wall 310 .

The outer wall 310 may be provided in the form of a polygonal column, and may be provided so that lines pass through each side thereof. However, as described above, the configuration for supplying the inert gas and the configuration for discharging the inert gas may be provided on opposite sides of each other.

The upper wall 320 is supported by the outer wall 310 and the dome cover 400 is seated at least in part. The upper wall 320 may be configured to be vertically fixed to the upper end of the outer wall 310 , and may be provided horizontally and parallel to the upper wall 110 .

The upper wall 320 may be provided in a shape protruding to the outside of the outer wall 310 , and the dome cover 400 may be inserted therein. In addition, the width of the upper wall 320 is provided to be at least equal to or greater than the thickness of the wall 110 , thereby sealing the primary insulating space 12 and the secondary insulating space 13 .

The support 330 extends downward from the upper wall 320 on the inner side of the outer wall 310 . The support 330 may be provided in a shape bent at an obtuse angle, and is provided to seal the secondary heat insulating space 13 by interconnecting the secondary barrier 113 and the upper wall 320 .

The support 330 may correspond to the outer wall 310 and may be provided parallel to the outer wall 310 . At this time, the support 330 includes a vertical part (not shown) parallel to the outer wall 310, and an inclined part (not shown) bent or bent toward the storage space 11 from the lower side of the vertical part. . At this time, a secondary barrier 113 may be provided between the inclined portion and the secondary heat insulating wall 114 for sealing, and the level difference between the vertical portion and the secondary heat insulating wall 114 may be resolved through the inclination of the inclined portion. can

In addition, as at least four supports 330 are provided and the corners between the supports 330 are also closed with a member having a bent or bent shape, the support 330 can form a polygonal column shape similar to the outer wall 310 . have.

Step resolution means 340 is provided at the inner end of the upper wall 320, the primary barrier 111 is connected to the inner surface. The step removing means 340 may have a U-shape in cross section, and the upper surface may be fixed by welding or the like while overlapping the inner end of the upper wall 320 .

A primary barrier 111 may be sealed on the inner surface of the step removing means 340 by welding or the like. Therefore, the outer side of the primary barrier 111 is sealed through the step removing means 340 and the upper wall 320, and the primary insulating space 12 can be formed as a closed space.

The lower surface of the step removing means 340 may not be fixed to the inner end of the upper wall 320 . This is because the height of the step removing means 340 is provided to be greater than the thickness of the upper wall 320 . However, a separate fixing member (not shown, wood or insulating block, etc.) is sandwiched between the lower surface of the lower surface of the step removing means 340 and the upper wall 320 to secure the fixing force.

The step removing means 340 is provided to resolve the step difference between the inner end of the upper wall 320 and the primary barrier 111 . That is, the inclined portion of the step removing means 340 and the support 330 is configured to seal and fix the primary barrier 111 and the secondary barrier 113 to the dome coaming 300 , respectively.

At this time, the step resolving means 340 adjusts the degree of overlap between the upper surface and the upper wall 320, and by adjusting the degree of inclination of the inclined portion of the support 330, the first barrier 111 / second barrier 113 is constructed. It is possible to secure the sealing by eliminating the step difference. Alternatively, in the case of the secondary barrier 113, it is possible to implement step resolution by applying foam.

In addition, the support 330 has only a horizontal portion perpendicular to the outer wall 310, and the secondary barrier 113 finished on the support 330 is made of a flexible material so that the secondary barrier 113 is bent in the form of the support 330 ) and a structure such as to seal between the secondary heat insulating wall 114 is also possible. In addition, the secondary barrier 113 may be connected to the support 330 and not the step removing means 340 and sealed.

A fixing member may be separately provided between the lower surface of the step resolving means 340 and the lower end of the upper wall 320 , wherein the fixing member is separately provided and fitted to the upper wall 320 , or welded to the upper wall 320 . It may be a structure that is fixed after being integrated with the

Through the structure of such a dome coaming 300, the hull is connected to the outer wall 310 and the secondary barrier 113 is connected to the support 330 through the inclined portion, and the upper wall 320 is the outer wall 310 and the support As the space between the 330 is sealed, the secondary thermal insulation space 13 is formed as a closed space.

Also, since the primary barrier 111 is connected to the upper wall 320 through the step removing means 340 and the space between the step removing means 340 and the support 330 is sealed with the upper wall 320, the primary insulating space 12 ) can also be made into a closed space.

That is, the dome coaming 300 closes the primary insulating space 12 between the primary barrier 111 and the secondary barrier 113, and also the secondary insulating space 13 between the secondary barrier 113 and the hull. ) can be closed. At this time, various lines are provided in the dome coaming 300 to pass through, and the supply/discharge of inert gas can be implemented by communicating the primary insulating space 12 / secondary insulating space 13 with the outside.

Specifically, it will be described with reference to FIG. 12 and the like. The inert gas supply line 22 is provided on one side of the dome coaming 300 and the inert gas discharge line is provided on the other side of the dome coaming 300 as described above.

In more detail, on one side (FIG. 9) of the dome coaming 300, a first inert gas supply line 22a (A, B, C, D, L) for supplying an inert gas to the primary insulating space 12 is provided. , M) and a second inert gas supply line 22b for supplying the inert gas to the secondary insulating space 13 is provided.

In addition, on the other side (FIG. 10) opposite to the one side shown in FIG. 9, the first inert gas discharge line 23a (G) for discharging the inert gas in the primary insulating space 12 and the secondary insulating space 13 in A second inert gas discharge line 23b (H) for discharging the inert gas may be provided.

Also, a first pilot line 25a and a second pilot line 25b, which will be described in detail below with reference to FIG. 20 , may be provided on the other side of the dome coaming 300 shown in FIG. 10 .

In addition, on the side ( FIG. 11 ) between the one side of FIG. 9 and the other side of FIG. 10 , first safety vent lines 24a (E) and second safety vent lines 24b and (J) to be described below are provided. may be provided, and first pilot lines 25a (F) and second pilot lines 25b and (I) may be additionally provided. That is, unlike in FIG. 20 , the first pilot line 25a (F) and the second pilot line 25b (I) may be provided at at least two points in the dome coaming 300 .

With respect to the arrangement of the lines provided to pass through the dome coaming 300 , the first inert gas supply line 22a is first viewed as shown in FIG. 12 . As shown in FIG. 12 , the first inert gas supply line 22a extends from the outside through the outer wall 310 and the support 330 to the primary insulating space 12 .

At this time, the first inert gas supply line 22a is provided to be bent or bent at least twice between the outer wall 310 and the support 330 to prepare for contraction and expansion, and the first inert gas supply line 22a passes through Of course, the outer wall 310 and the like may be provided with sufficient sealing to prevent leakage of liquefied gas.

The first inert gas supply line 22a (A, B, C, D, M) shown in FIG. 12 passes through the support 330 and then along the outer surface of the primary barrier 111 of the storage space 11 . It is provided to extend downward, and an inert gas may be supplied to the lower portion of the primary heat insulating space 12 .

Of course, some (M) of the first inert gas supply line (22a), as shown in FIG. 13, instead of extending downward along the outer surface of the primary barrier 111, at a point immediately after passing through the support 330 By forming the end, it may be provided to supply an inert gas to the upper portion of the primary insulating space 12 .

The first inert gas supply line 22a may be provided with different diameters of some (A, B, C, D, M) shown in FIG. 12 and the rest (L) shown in FIG. 13 , which is the primary insulation The shape or size of the space 12 may be determined according to various variables such as liquefied gas specifications.

Although not shown as a cross-sectional view, the second inert gas supply line 22b shown in FIG. 20 passes through the outer wall 310 of the dome coaming 300 from the outside and does not pass through the support 330 and does not pass through the secondary insulating space. (13) can be extended.

Hereinafter, an inert gas discharge line will be described. First, the first inert gas discharge line is as shown in FIG. 14 . The first inert gas discharge line may be provided to extend from the primary insulating space 12 through the support 330 and the outer wall 310 to the outside, and in this case, at least 2 between the support 330 and the outer wall 310 . It may be provided to be bent or bent.

The first inert gas discharge line G shown in FIG. 14 may be formed to be symmetrical with the first inert gas supply lines 22a and L shown in FIG. 13 and may be provided to have diameters corresponding to each other. In addition, the inlet end of the first inert gas discharge line may be located above the primary insulating space 12 .

Referring to FIG. 15 , the second inert gas discharge line H may extend from the secondary insulating space 13 to the outside through the outer wall 310 . In this case, a strainer (not shown) may be provided at the inlet end of the second inert gas discharge line. The strainer is similar to a filter and can restrict the inflow and outflow of foreign substances by using a structure such as a mesh or membrane.

In addition, the dome coaming 300 may be provided with a configuration for urgently discharging gas in the insulating spaces 12 and 13 when the internal pressure of the insulating spaces 12 and 13 becomes excessive, for example, a safety vent line 24a , 24b) and pilot lines 25a and 25b for opening the safety vent lines 24a and 24b.

The opening of the safety vent lines 24a and 24b through the pilot lines 25a and 25b will be described later, and the arrangement of the above lines will be described from a structural point of view.

First, in the case of the safety vent lines 24a and 24b, as shown in FIG. 16 , when the internal pressure of the primary insulating space 12 is greater than or equal to a preset pressure, a first safety vent that communicates the inside of the insulating space 12 and 13 with the outside Lines 24a (E) are provided.

The first safety vent lines 24a and E are provided to extend outside through the support 330 and the outer wall 310 in the primary insulating space 12 . The first safety vent line 24a may have a structure similar to that of the first inert gas supply line 22a shown in FIG. 13 , but the gas flow may be reversed. Also, the first safety vent line 24a may have a structure similar to that of the first inert gas discharge line shown in FIG. 14 in the dome coaming 300 .

The second safety vent lines 24b (J) are as shown in FIG. 17 . The second safety vent line 24b is provided to extend outside through the outer wall 310 in the second heat insulating spaces 12 and 13 . That is, the first safety vent line 24a and the second safety vent line 24b extend to the outside through at least the outer wall 310 in the insulating spaces 12 and 13 .

The second safety vent line 24b may be provided in a structure similar to that of the second inert gas discharge line shown in FIG. 15 , and a strainer (not shown) is also provided at the inlet end of the second safety vent line 24b. can be provided.

Safety valves 241 and 242 are provided in the safety vent lines 24a and 24b, and the safety valves 241 and 242 may operate using the pilot lines 25a and 25b as control lines. In this case, the first pilot line 25a may be allocated to the first safety vent line 24a, and the second pilot line 25b may be allocated to the second safety vent line 24b.

The first pilot line 25a and the second pilot line 25b pass through at least the outer wall 310 in the insulating spaces 12 and 13 to form the first safety vent line 24a/second safety vent line 24b. It may extend and be connected to the first safety valve 241/second safety valve 242 .

As shown in FIG. 18 , the first pilot line 25a passes through the support 330 in the first insulating spaces 12 and 13 and then through the outer wall 310 to extend to the first safety valve 241 . .

Also, as shown in FIG. 19 , the second pilot line 25b may extend to the second safety valve 242 after penetrating the outer wall 310 in the second insulating spaces 12 and 13 . In this case, a strainer (not shown) may be provided at the inlet end of the second pilot line 25b.

The first pilot line 25a/second pilot line 25b may have a smaller diameter than the first safety vent line 24a/second safety vent line 24b. In the case of the pilot lines 25a and 25b, the control hydraulic pressure for the operation of the safety valves 241 and 242 is transmitted, whereas the safety vent lines 24a and 24b urgently increase the internal pressure of the insulating spaces 12 and 13. Because it is a configuration that needs to be lowered.

In this way, the dome coaming 300 may be provided so that the following lines are penetrated.

The left side of FIG. 8: inert gas supply line 22

Right side of Fig. 8: inert gas discharge line/pilot line (25a, 25b)

The upper side of Fig. 8: safety vent lines (24a, 24b)/pilot lines (25a, 25b)

Of course, the above arrangement can be changed at any time. However, the inert gas supply line 22 and the inert gas discharge line are provided on opposite sides of each other so that the inert gas is sufficiently introduced into the insulating spaces 12 and 13 to maintain the pressure of the insulating spaces 12 and 13 at a constant value. It is preferable to be

The dome cover 400 is seated inside the dome coaming 300 described above, so that the dome 10 can be sealed. At this time, the dome cover 400 may have liquefied gas lines 430 , 431 , 440 , and 441 for the inflow and outflow of the liquefied gas pass through. In addition, the dome cover 400 is a boil-off gas for the discharge (inflow) of the boil-off gas. Since the line 460 is also penetrated, the dome 10 of the present invention may be configured as a complex dome 10 that can allow inflow and outflow of boil-off gas as well as liquefied gas.

That is, the dome 10 of the present invention is a BOG discharge line for discharging BOG generated in the storage space 11 together with the liquefied gas lines 430, 431, 440, 441 to the dome cover 400 ( As the 460) is provided, it is provided as a composite dome 10 in which both liquefied gas and boil-off gas flow in and out.

Therefore, the composite dome 10 of the present invention may be configured as a composite dome in which a liquid dome and a boil-off gas dome are integrated.

The dome cover 400 provided in the composite dome 10 includes a frame 410 and a heat insulating material 420 . The frame 410 may be coupled to the upper wall 320 of the dome coaming 300 . The frame 410 may have a frame structure, and as shown in FIGS. 2 to 4 , the liquefied gas lines 430, 431, 440, 441/evaporated gas line 460, etc. are penetrated and the liquefied gas line 430, 431, 440, 441) and the like are provided to support.

To this end, the liquefied gas lines 430 , 431 , 440 , 441 and the like may be connected to the frame 410 through the line fixing part 480 , which will be described in detail below.

A liquefied gas discharge line 430 and a liquefied gas loading line 440 for the inflow and outflow of liquefied gas are passed through the frame 410 . In addition, since the dome 10 of the present invention is provided as a composite dome 10 , the BOG discharge line 460 for discharging BOG may also pass through the frame 410 of the dome cover 400 .

At this time, the liquefied gas discharge line 430 is made of at least one pair, and the pair of liquefied gas discharge line 430 and the liquefied gas loading line 440 may be arranged to form a triangle.

In addition, the dome cover 400 is provided so that the emergency treatment line 431 (emergency pipe) passes through at a position adjacent to the liquefied gas loading line 440, so that the liquefied gas discharge through the liquefied gas discharge line 430 cannot be achieved. In this case, it is also possible to implement the discharge of the liquefied gas through the emergency treatment line (431).

The liquefied gas discharge line 430 and the emergency treatment line 431 extend downward from the dome cover 400 toward the storage space 11 while forming a triangular pole shape to configure a pump tower. At this time, a cargo pump or a spray pump for discharging liquefied gas to the liquefied gas discharge line 430 may be provided at the lower end of the pump tower.

The dome cover 400 may be provided with a cable pipe 432 for connecting a cable for the operation of the cargo pump to the cargo pump from the outside, and the cable pipe 432 is the number of pumps provided in the storage space 11 . It may be provided correspondingly.

The liquefied gas loading line 440 described above may extend below the storage space 11 . However, in order to prepare for the need to load the liquefied gas in the upper portion of the storage space 11 , a top filling line 441 extending to the upper portion of the storage space 11 may be provided through the dome cover 400 .

In addition, the dome cover 400 is provided with a safety vent line 450 having a function similar to that of the safety vent lines 24a and 24b allocated to the above-described insulating spaces 12 and 13, and the internal pressure of the storage space 11 is provided. You can prepare for when it rises. At this time, the safety vent line 450 may be provided in at least one pair so as to be able to back up each other.

In addition, a pilot line 451 similar to that described above is also provided in the dome cover 400, and the safety valve (not shown) provided in the safety vent line 450 according to the internal pressure of the storage space 11 is automatically opened. , the internal pressure of the storage space 11 may be lowered through the safety vent line 450 .

In addition to this, the dome cover 400 may be provided with various lines necessary to communicate the inside of the storage space 11 with the outside, and for example, a CTS line for a sensor, a spray line, a gas sampling line, etc. may be provided. can

In addition, the dome cover 400 is provided with a maintenance hole 471 (maintenance hole) that allows the operator to enter after the operation of replacing the inside of the storage space 11 to a state where the worker can be introduced, and also the storage space (11) Equipment through-opening 472 (material passage), etc. for flowing in and out of the internal configuration may be provided.

The dome 10 described in this way is provided with a liquefied gas discharge line 430, an emergency treatment line 431, a liquefied gas loading line 440, a top filling line 441, etc. for the inflow and outflow of the liquefied gas. can function as

In addition to this, the dome 10 of the present invention can integrate the function of the boil-off gas dome into the liquefied gas dome as a composite dome 10 . To this end, the dome cover 400 may be provided with a boil-off gas discharge line 460 for discharging the boil-off gas in the storage space 11 .

The boil-off gas discharge line 460 may be disposed outside the triangle formed by the liquefied gas discharge line 430 and the liquefied gas loading line 440 (emergency treatment line 431), and the liquefied gas loading line 440 may be placed adjacent to

Unlike the liquefied gas discharge line 430 , the boil-off gas discharge line 460 is for discharging the boil-off gas generated in the storage space 11 , and may be provided such that the lower end extends only to the upper portion of the storage space 11 .

That is, as the dome 10 of the present invention is provided as a composite dome 10 in which both liquefied gas and boil-off gas are provided to flow in and out through one dome cover 400, the liquefied gas dome and the boil-off gas dome are separately provided. there will be no need

In this way, a heat insulating material 420 may be provided on the inner surface of the frame 410 of the dome cover 400 through which lines pass in order to implement the inflow and outflow of liquefied gas and boil-off gas. The heat insulating material 420 is provided on the inner surface facing the storage space 11 from the frame 410, and the primary insulating wall 112 / secondary insulating wall constituting the wall 110 of the liquefied gas storage tank 100 ( 114) and may be made of the same/similar material.

The dome cover 400 may be provided in a form in which the heat insulating material 420 is exposed toward the storage space 11 . However, the dome cover 400 is positioned above the storage space 11 by the protrusion 116 and the like, and even if the liquefied gas filled in the storage space 11 flows, it passes through the protrusion 116 and is delivered to the dome cover 400 . The probability of being Accordingly, a barrier may be omitted on the inner surface of the dome cover 400 .

Of course, the same / similar barrier as the primary barrier 111 of the wall 110 is added to the inner surface of the insulating material 420 of the dome cover 400, so that the frame 410 has the function of the secondary barrier 113. It is possible.

The frame 410 and the insulator 420 are stacked in two layers, and the above-described lines may be provided to pass through the frame 410 and the insulator 420 at once. In this case, the line is fixed to the frame 410 through the line fixing unit 480 .

The line fixing part 480, as shown in FIGS. 6 and 7, fixes the line to the frame 410, and the heat insulating member 481, the peripheral member 482, the washer member 483, and the finishing member 484. ), including a rib bracket (485). The line fixing unit 480 to be described below will be described as an example of a configuration for fixing the boil-off gas discharge line 460 , and the following description may be applied to a portion for fixing other lines to the frame 410 .

The heat insulating member 481 wraps around a portion of the BOG line 460 penetrating the frame 410 and the heat insulating material 420 . The insulating member 481 may be made of the same/similar material as the primary insulating wall 112 and the insulating material 420 , or may be made of a different material (eg, glass wool, etc.).

The heat insulating member 481 surrounds the boil-off gas line 460 to prevent the cryogenic temperature inside the boil-off gas line 460 from being transmitted to the frame 410 , and on the contrary, heat from the outside is transferred into the boil-off gas line 460 inside. transmission can be blocked.

The heat insulating member 481 is provided to sufficiently suppress external heat penetration by covering the boil-off gas line 460 from the upper end of the frame 410 to a predetermined height upward. In addition, the heat insulating member 481 may not be exposed to the outside since the lower end is closed by the washer member 483 and the upper end is closed by the closing member 484 .

The circumferential member 482 is provided parallel to the boil-off gas line 460 and surrounds the outside of the heat insulating member 481 . The circumferential member 482 may be provided in a cylindrical shape to correspond to the boil-off gas line 460 , and may be formed in a hollow shape having a diameter for accommodating the boil-off gas line 460 therein.

At this time, the difference between the inner diameter of the peripheral member 482 and the outer diameter of the boil-off gas line 460 may be made to correspond to the thickness of the heat insulating member 481 . In addition, the outer surface of the circumferential member 482 may be fixed to the frame 410 by welding or the like, and the upper end of the circumferential member 482 is sealed by a closing member 484 . Therefore, since the portion of the frame 410 through which the boil-off gas line 460 passes is sealed through the peripheral member 482 and the closing member 484 , leakage is not made.

The circumferential member 482 may have a lower end extending downward of the frame 410 to be located inside the heat insulating material 420 . Through this, a space between the frame 410 and the boil-off gas line 460 may be smoothly sealed by the peripheral member 482 (and the closing member 484 ).

The washer member 483 is provided perpendicular to the boil-off gas line 460 and is connected to the heat insulating material 420 to close the lower end of the heat insulating member 481 . The washer member 483 is sealingly connected to the lower surface (inner surface) of the heat insulating material 420 and the outer periphery of the boil-off gas line 460 to cover the lower side of the heat insulating member 481, using a method such as bolting or bonding. It may be fixed to the insulator 420 or the like.

In the case of the upper end of the heat insulating member 481 , the upper portion may be sealed by the circumferential member 482 and the closing member 484 while being provided to extend upward from the lower surface of the frame 410 . On the other hand, the lower end of the insulating member 481 may be provided (almost) parallel to the lower surface of the insulating material 420 of the dome cover 400, and the washer member 483 is disposed between the insulating material 420 and the boil-off gas line 460. It is provided to cover the lower end of the heat insulating member 481 in the.

However, the insulating material 420 of the dome cover 400 is substantially exposed to the storage member as it is, and the frame 410 and the peripheral member 482 and the finishing member 484 can implement a barrier function, and the washer member ( The 483 may be provided to fix the lower end of the heat insulating member 481 rather than sealing the heat insulating member 481 between the heat insulating material 420 and the boil-off gas line 460 .

The closing member 484 is provided perpendicular to the boil-off gas line 460 and is connected to the upper end of the peripheral member 482 to close the upper end of the heat insulating member 481 . The closing member 484 may be sealingly connected to the upper end of the circumferential member 482 and the outer periphery of the boil-off gas line 460 to seal the open upper side of the circumferential member 482 .

To this end, the closing member 484 is provided to have a larger outer diameter than the circumferential member 482 to sufficiently cover the upper end of the circumferential member 482, thereby covering between the circumferential member 482 and the boil-off gas line 460. .

As described above, since the heat insulating member 481 has a sufficient height to suppress heat penetration into the boil-off gas line 460 , the peripheral member 482 surrounding the heat insulating member 481 also has an upper end of the frame 410 . It may be located higher.

At this time, the closing member 484 connected to the boil-off gas line 460 at the upper end of the peripheral member 482 may be positioned above the frame 410 to be exposed to the outside. At this time, the rib bracket 485 connected to the boil-off gas line 460 may be provided on the closing member 484 to stably support the boil-off gas line 460 .

The rib bracket 485 connects and supports the boil-off gas line 460 exposed upward of the heat insulating member 481 to the closing member 484 . The rib bracket 485 may have a triangular shape and a plurality of rib brackets may be provided radially along the circumference of the boil-off gas line 460 .

In the present invention, by connecting the boil-off gas line 460 to the closing member 484 through the rib bracket 485 in an oblique direction, the strength of the support structure of the boil-off gas line 460 can be secured. Therefore, the present invention can sufficiently support the boil-off gas line 460 even if only one closing member 484 is provided perpendicular to the boil-off gas line 460 .

As described above, the liquefied gas storage tank 100 of this embodiment applies a composite dome 10 having a dome cover 400 that allows inflow and outflow of liquefied gas as well as boil-off gas, thereby reducing the risk of leakage and greatly simplifying the structure. can do.

Hereinafter, the gas processing system 1 applied to the complex dome 10 of the liquefied gas storage tank 100 described above will be described in detail based on the conceptual diagram shown in FIG. 20 .

For reference, although not shown in the drawings of the present invention, a pressure sensor (PT), a temperature sensor (TT), etc. may be provided at an appropriate position without limitation, of course, and the measurement value by each sensor is one of the components described below. It can be used in various ways without limitation in operation.

20 is a conceptual diagram of a gas processing system according to an embodiment of the present invention.

Referring to FIG. 20 , the gas processing system 1 according to an embodiment of the present invention includes a liquefied gas storage tank and an inert gas processing unit 20 .

For reference, in the drawing, PIC denotes a pressure indicating controller, which is a pressure controller, and DPIC denotes a differential pressure indicating controller, which denotes a differential pressure controller.

PIC and DPIC are components for controlling valves described below, and may be interchanged or omitted/added freely. In addition, the PIC and the like can be replaced with other components that control variables (temperature, etc.) for controlling the opening degree of the valve in addition to the pressure.

The liquefied gas storage tank has a storage space 11 for storing liquefied gas. In this case, the liquefied gas storage tank may include insulating spaces 12 and 13 around the storage space 11 in order to store the liquefied gas in a cryogenic liquid phase.

The insulating spaces 12 and 13 may be provided in at least two layers, and the primary insulating space 12 provided outside the storage space 11, the primary insulating space 12 and the liquefied gas storage tank are mounted. It may include a secondary thermal insulation space 13 provided between the hulls.

The primary insulating space 12 may be referred to as an Interbarrier Space (IBS), and the secondary insulating space 13 may be referred to as an Insulation Space (IS).

The liquefied gas storage tank may have a structure in which a primary barrier, a primary thermal insulation wall, a secondary barrier, and a secondary thermal insulation wall are sequentially stacked from the storage space 11 toward the hull. At this time, the primary barrier is made of a metal material such as SUS, INVAR, etc., and may be provided in a configuration to prevent leakage of liquefied gas by direct contact with liquefied gas.

In addition, the secondary barrier may be made of the same/similar metal material as the primary barrier, or may be made of a composite material in which a glass fiber sheet is variously laminated on a metal sheet to prevent gas leakage.

The primary insulating wall and the secondary insulating wall may be made of a synthetic resin material, and may be made of, for example, polyurethane foam. Alternatively, it may be made in the form of a box in which an insulating material such as perlite is embedded.

The primary insulating wall and the secondary insulating wall are provided for thermal insulation, and may have a structure (eg, an open cell, etc.) capable of flowing gas therein. In this case, the primary insulating wall may be referred to as a primary insulating space 12 , and the secondary insulating wall may be referred to as a secondary insulating space 13 .

The primary insulating space 12 may be a closed space between the primary barrier and the secondary barrier, and the secondary insulating space 13 may be a closed space between the secondary barrier and the hull. At this time, since the internal pressure of the primary insulating space 12 and the secondary insulating space 13 is maintained at an appropriate value, it is possible to secure storage stability of the liquefied gas in the storage space 11 .

For example, the primary insulating space 12 may be maintained at a pressure less than or equal to the storage space 11 , and the secondary insulating space 13 may be maintained at a pressure higher than that of the primary insulating space 12 . In this case, an inert gas may be used to maintain the pressure of the insulating spaces 12 and 13, and the inert gas may be, for example, nitrogen gas.

A composite dome 10 is provided on the upper side of the storage space 11 in the liquefied gas storage tank. The complex dome 10 may be provided at a position adjacent to the front wall or the rear wall on the upper surface of the liquefied gas storage tank, and may have a configuration through which a pump tower (not shown) penetrates.

The composite dome 10 may be provided with a dome coaming projecting upward from the upper surface of the liquefied gas storage tank and having an opening, and a dome cover covering the opening of the dome coaming. For reference, the part shown in the drawing corresponds to the dome coaming.

The complex dome 10 is provided to communicate with the outside the storage space 11 for storing liquefied gas, and the line through which the liquefied gas on the pump tower flows (loading line, unloading line, emergency pipe, etc., not shown) It may be provided to pass through.

In addition, the complex dome 10 may be provided with an evaporation gas line (not shown) for treating the boil-off gas generated in the storage space 11 while communicating the storage space 11 with the outside. That is, the complex dome 10 may be provided with both a liquefied gas line through which liquefied gas flows and a boil-off gas line through which boil-off gas flows.

However, in the complex dome 10, the liquefied gas line extends downward to be submerged in the liquefied gas accommodated in the storage space 11, and the boil-off gas line may be provided so that the lower end is located on the liquid level of the liquefied gas of the storage space 11. . In this case, the liquefied gas line extends to the lower side of the storage space 11 to constitute a pump tower constrained by a base support (not shown), whereas the boil-off gas line penetrates the dome cover separately from the pump tower. may be arranged to do so.

Therefore, in this embodiment, a liquid dome for the treatment of liquefied gas and a gas dome for the treatment of boil-off gas generated by natural vaporization in the liquefied gas storage tank are provided, respectively, instead of a complex dome (10) (combined dome) can be provided so that liquefied gas and boil-off gas are processed through one configuration.

The inert gas processing unit 20 supplies the inert gas into the heat insulation spaces 12 and 13 or discharges the inert gas in the heat insulation spaces 12 and 13 . The inert gas may be nitrogen gas, but an inert gas other than nitrogen may also be used.

The inert gas processing unit 20 has a configuration for supplying an inert gas into the heat insulating spaces 12 and 13, a configuration for discharging the inert gas from the heat insulating spaces 12 and 13, and the internal pressure of the heat insulating spaces 12 and 13. When this set value is exceeded, it may include a configuration for communicating the insulating spaces 12 and 13 with the outside for emergency use, a configuration for inspecting gas in the insulating spaces 12 and 13, and the like.

First, a configuration for supplying an inert gas will be described. The inert gas is delivered to the adiabatic spaces 12 and 13 by the inert gas supply unit 21 (N2 supply system, etc.) for generating the inert gas, and in the inert gas supply unit 21 as above, the adiabatic spaces 12 and 13 The inert gas supply line 22 may be provided. The inert gas supply line 22 supplies the inert gas into the insulating spaces 12 and 13 through the complex dome 10 to increase the internal pressure of the insulating spaces 12 and 13 .

An inert gas supply valve (not shown) may be provided in the inert gas supply line 22 , and the inert gas supply valve may be set to a value of, for example, about 400 mbarg to adjust the opening degree. For this purpose, a PIC capable of adjusting the pressure in a range encompassing 400 mbarg may be used (eg, a pressure adjustment of 200 to 550 mbarg is possible).

A plurality of liquefied gas storage tanks are provided in the hull, and one inert gas supply unit 21 may be allocated to the complex dome 10 provided in each liquefied gas storage tank.

Therefore, the inert gas supply line 22 allocated to any one liquefied gas storage tank is partially branched and connected to the inert gas supply line 22 of the other liquefied gas storage tank, and one inert gas supply unit 21 ) to the plurality of complex domes 10 to allow the inert gas to be smoothly distributed.

The inert gas supply line 22 may be provided in each of the primary insulating space 12 and the secondary insulating space 13 , and a plurality of first inert gas supply lines 22a in the primary insulating space 12 . This may be provided.

For example, the first inert gas supply line 22a has supply ends indicated by A to D in the drawing. In this case, A to D may be configured to inject an inert gas into the lower portion of the primary insulating space 12 .

In addition, the first inert gas supply line 22a having the supply ends of A to D may be provided for stripping out of the liquefied gas leaked from the primary insulating space 12 to the outside.

Also, the first inert gas supply line 22a may further include supply ends indicated by L and M in the drawing. In this case, L may be a configuration for injecting an inert gas into the upper portion of the primary insulating space 12, and M may be a configuration for injecting an inert gas into the lower portion of the primary insulating space 12 similarly to A.

The first inert gas supply line 22a having the supply ends of L and M may be configured for portable gas sampling, and in the case of L, for the lower portion of the primary insulating space 12 In the case of gas sampling, M may be provided for gas sampling of the upper portion of the primary insulating space 12 .

A first inert gas supply valve 221 may be provided in the first inert gas supply line 22a. The first inert gas supply valve 221 may allow the internal pressure of the primary insulating space 12 to be maintained in a range that does not exceed approximately 30 mbarg.

At this time, the first inert gas supply valve 221 may be controlled in consideration of the internal pressure of the primary insulating space 12 , and may be controlled in consideration of the internal pressure of the secondary insulating space 13 (together). To this end, the opening degree of the first inert gas supply valve 221 may be adjusted through the PIC controlling the pressure of the secondary insulating space 13 .

A second inert gas supply line 22b may be provided in the secondary heat insulating space 13 . The second inert gas supply line 22b is provided to be provided in parallel with the first inert gas supply line 22a and may be connected to one inert gas supply unit 21 .

The second inert gas supply line 22b may be provided in the lower portion of the secondary thermal insulation space 13 , and may be provided in one or more as indicated by K in the drawing. However, since the secondary insulation space 13 is adjacent to the hull side compared to the primary insulation space 12 adjacent to the storage space 11, the risk of gas leakage is relatively low, so the inert gas supply for purging is the primary It may be smaller than the insulating space 12 .

Therefore, the first inert gas supply line 22a is provided in plurality to continuously supply the inert gas in the primary insulating space 12, while the second inert gas supply line 22b is the first inert gas supply line ( 22a) may be provided in a smaller number compared to that.

In addition, a second inert gas supply valve 222 may be provided in the second inert gas supply line 22b. Like the first inert gas supply valve 221 , the second inert gas supply valve 222 may be controlled based on the pressure of the secondary insulating space 13 . At this time, the second inert gas supply valve 222 may be controlled to maintain an appropriate pressure such that the internal pressure of the secondary insulating space 13 is approximately 35 mbarg or less.

The second inert gas supply valve 222 may be controlled by considering the internal pressure of the primary insulating space 12 and the secondary insulating space 13 in combination. To this end, the DPIC may control the second inert gas supply valve 222 based on the differential pressure between the primary insulating space 12 and the secondary insulating space 13 .

Hereinafter, a configuration for discharging the inert gas from the insulating spaces 12 and 13 will be described.

The inert gas processing unit 20 includes inert gas discharge lines 23a and 23b for discharging the inert gas in the insulating spaces 12 and 13 through the complex dome 10 to lower the internal pressure of the insulating spaces 12 and 13 . At this time, the inert gas discharge lines 23a and 23b are a first inert gas discharge line 23a provided in the primary heat insulation space 12 and a second inert gas discharge line 23b provided in the secondary heat insulation space 13. may include

The first inert gas discharge line 23a is indicated by G in the drawing, and the inert gas injected into the primary heat insulating space 12 so that the internal pressure of the primary insulating space 12 can maintain an appropriate pressure within about 30 mbarg. At least a portion of the gas may be discharged to the outside.

At this time, the first inert gas discharge line 23a may be connected to the vent mast 26 so that the inert gas discharged from the primary insulating space 12 is discharged from the vent mast 26 . However, as will be described later, in the case of the secondary insulating space 13, the inert gas discharged through the second inert gas discharge line 23b may be simply discharged to the atmosphere, which is the case of the liquefied gas in the case of the primary insulating space 12. This is because there is a risk of leakage and it is dangerous for simple air discharge.

The first inert gas discharge line 23a is provided with a first inert gas discharge valve 231 as in the first inert gas supply line 22a. At this time, as described in the first inert gas supply valve 221 , the opening degree of the first inert gas discharge valve 231 is adjusted by the internal pressure of the primary insulating space 12 , or the internal pressure of the secondary insulating space 13 is reduced. The opening degree can be controlled by the controlling PIC.

The first inert gas discharge line 23a may have a first safety vent line 24a branched in the middle extending from the primary insulating space 12 to the vent mast 26 . The first safety vent line 24a may be provided at at least two points in the complex dome 10, and any one of the first safety vent lines 24a may be branched from the first inert gas discharge line 23a. . This will be described later.

The second inert gas discharge line 23b is indicated by H in the drawing, and the inert gas injected into the secondary thermal insulation space 13 is discharged so that the secondary thermal insulation space 13 maintains an appropriate pressure within approximately 35 mbarg. can be discharged

At this time, the second inert gas discharge line 23b may be provided to discharge the inert gas to the atmosphere, which is, as described above, the secondary insulating space 13 has a higher risk of leakage of liquefied gas compared to the primary insulating space 12 . because there are few

The second inert gas discharge line 23b is provided with a second inert gas discharge valve 232 . At this time, the second inert gas discharge valve 232 may be controlled to properly maintain the internal pressure of the secondary insulating space 13 . In addition, the second inert gas discharge valve 232 is the same/similar to the second inert gas supply valve 222 , by the DPIC for controlling the internal pressure difference between the primary insulating space 12 and the secondary insulating space 13 . The degree of opening can be adjusted.

A second safety vent line 24b may be provided also in the second inert gas discharge line 23b as described in the first inert gas discharge line 23a. That is, the second safety vent line 24b may also be provided at at least two points in the secondary thermal insulation space 13 communicating with the composite dome 10 , and any one of the second safety vent lines 24b is the second It may be branched to the inert gas discharge line 23b.

The inert gas discharge lines 23a and 23b described as described above are provided opposite to the inert gas supply line 22 in the complex dome 10 . This is because when the inert gas supply line 22 and the inert gas discharge lines 23a and 23b are provided in a position close to each other in the complex dome 10, the inert gas is not properly filled in the insulation spaces 12 and 13, and the insulation This is because the internal pressure of the spaces 12 and 13 is inevitably less than the required appropriate pressure.

Therefore, as shown in the figure, in contrast to A to D and L and M, which are the first inert gas supply lines 22a, the first inert gas discharge lines 23a are opposite to each other with respect to the center of the complex dome 10. may be disposed, where the opposite may mean located opposite in the front-rear direction or left-right direction of the hull.

Of course, the arrangement of the first inert gas supply line 22a and the first inert gas discharge line 23a is not limited to opposite sides, and the inert gas supply and discharge are provided on different adjacent surfaces, or on one surface. These may be spaced apart so as not to interfere with each other.

In addition, since it is possible that the cross-sectional shape of the dome coaming 300 is not polygonal, the arrangement of the first inert gas supply line 22a and the first inert gas discharge line 23a allows the supply/discharge of the inert gas without mutual interference. It can be variously determined under conditions that can be stably implemented.

In addition, the second inert gas supply line (22b), K, and the second inert gas discharge line (23b), H, is also disposed on the opposite side with respect to the center of the complex dome (10).

In this case, the inert gas supply and the inert gas discharge may be made at different times so as not to be performed simultaneously. That is, the inert gas supply line 22 and the inert gas discharge lines 23a and 23b are controlled to be opened alternatively.

Such control may be implemented by controlling the inert gas supply valves 221 and 222 and the inert gas discharge valves 231 and 232 so that when one of the inert gas discharge valves 231 and 232 is opened, the other is closed.

Through this, the present embodiment has a safety function in which the supply of the inert gas and the venting of the inert gas are not made at the same time, so that it is possible to precisely control the appropriate pressure in the heat insulating space 12 and 13, and thus, within 2 mm It is possible to eliminate the risk of deformation of the primary barrier or the secondary barrier made of a thin film.

That is, the present embodiment does not include a liquid dome (in charge of supplying inert gas) and a gas dome (in charge of discharging inert gas) spaced apart from each other, but a composite dome (10) that is integrally provided so that both liquefied gas and boil-off gas flow (combined dome), the inert gas supply valve (221, 222) and the inert gas discharge valve (231, 232) do not open at the same time when implementing the supply and discharge of the inert gas for one complex dome (10) By applying the safety function, it is possible to reduce a plurality of coamings to one coaming, and to effectively implement internal pressure control in the insulating spaces 12 and 13 .

Hereinafter, when the internal pressure of the heat insulating space (12, 13) exceeds a set value, the configuration for communicating the heat insulating space (12, 13) with the outside for an emergency will be described.

The inert gas processing unit 20 sets an appropriate pressure for each of the insulating spaces 12 and 13, and when the internal pressure of the insulating spaces 12 and 13 exceeds the set pressure, it is regarded as a dangerous situation and the insulating space 12, 13), the inert gas filled in can be forcibly discharged to the outside.

At this time, as an example, the setting pressure SP of the primary insulating space 12 is approximately 30 mbarg, and the setting pressure SP of the secondary insulating space 13 may be approximately 35 mbarg, but these values can be changed at any time.

When the internal pressure of the insulating space (12, 13) reaches a preset pressure (setting pressure) or more, in order to discharge the inert gas in the insulating space (12, 13), the safety of communicating the inside of the insulating space (12, 13) with the outside Vent lines 24a and 24b may be provided. The safety vent lines 24a and 24b may include a first safety vent line 24a provided in the primary insulating space 12 and a second safety vent line 24b provided in the secondary insulating space 13 . .

The first safety vent line 24a may be connected to the primary insulating space 12 through at least two points in the composite dome 10 . For example, the first safety vent line 24a is connected to the primary insulating space 12 at a point adjacent to a point where the first inert gas supply line 22a is provided (E in the drawing), and a first inert gas discharge line It may be branched from the first inert gas discharge line 23a so as to be connected to the primary insulating space 12 through a point (G in the drawing) at which 23a is provided.

Of course, the connection of the first safety vent line 24a to the primary insulating space 12 is not limited to the above.

A first safety valve 241 may be provided in the first safety vent line 24a. The first safety valve 241 automatically opens when the internal pressure of the primary insulating space 12 exceeds the set pressure and opens the first safety vent line 24a, so that the inert gas in the primary insulating space 12 is released. It can be discharged to the vent mast (26).

In this case, a first pilot line 25a may be provided from the primary insulating space 12 to the first safety valve 241 to open the first safety valve 241 . In the first pilot line 25a, a fluid such as an inert gas filled in the primary insulating space 12 is transferred to the first safety valve 241, and the first by the pressure of the fluid in the primary insulating space 12 It causes the safety valve 241 to open automatically.

The first pilot line 25a may be provided at a point F between the points E and G where the plurality of first safety vent lines 24a are connected to the primary insulating space 12 .

The second safety vent line 24b may be provided similarly to the first safety vent line 24a. A second safety vent line 24b is provided at at least two points in the complex dome 10 , and the second safety vent line 24b has a second inert gas supply line 22b connected to the secondary insulating space 13 . It is provided at a point (J) adjacent to the point (K) to be, or branched from the second inert gas discharge line (23b), so that a point (H) of the secondary insulating space (13) through the second inert gas discharge line (23b). ) can be connected to

The second safety vent line 24b is automatically opened when the internal pressure of the secondary insulating space 13 exceeds the set pressure of approximately 35 mbarg, and for this purpose, the second safety valve 242 is connected to the second safety vent line 24b. ) is provided.

The second safety valve 242 may be automatically opened when the internal pressure of the secondary insulating space 13 exceeds a preset pressure, and for this, the second safety valve 242 is provided with a second pilot line 25b.

Similar to the first pilot line 25a, the second pilot line 25b is a point between points K and H where the second safety vent lines 24b are connected to the secondary insulating space 13 (K, H). In I), it can be connected to the secondary insulating space 13, and when a fluid such as an inert gas filled in the secondary insulating space 13 is delivered to the second safety valve 242, the second safety valve 242 is automatically opened. to implement

As described above, a plurality of safety vent lines 24a and 24b and safety valves 241 and 242 are provided in each of the primary insulating space 12 and the secondary insulating space 13, and the primary insulating space 12 A pilot line so that the plurality of first safety valves 241 allocated to and the plurality of second safety valves 242 allocated to the secondary insulation space 13 are automatically opened by the internal pressure of the insulation spaces 12 and 13 . (25a, 25b) is provided. The pilot lines 25a and 25b are connected to a plurality of first safety valves 241 or a plurality of second safety valves 242 in the primary insulating space 12 or the secondary insulating space 13, and are connected to the insulating space ( 12, 13) can be directly transmitted.

Hereinafter, the configuration for inspecting the gas in the insulating space (12, 13) will be described.

It can be checked whether inert gas or the like is properly filled in the insulating spaces 12 and 13 and whether liquefied gas has not leaked, and for this purpose, the gas detection line 27a can be used.

A plurality of gas sensing lines 27a may be provided for each of the primary insulating space 12 and the secondary insulating space 13, and specifically, the gas sensing lines 27a are provided in the safety vent lines 24a and 24b. It may be provided branched. Accordingly, at least two gas detection lines 27a may be provided for each heat insulating space 12 and 13 .

The gas detection line 27a may deliver gas to a gas detector (not shown), and the gas detection line 27a branched from the upstream of the safety valves 241 and 242 in the safety vent lines 24a and 24b. Through the gas is delivered to the gas detector, it is possible to check whether the liquefied gas has leaked in which insulating space (12, 13).

Since the gas detection line 27a is provided to branch from the safety vent lines 24a and 24b upstream of the safety valves 241 and 242, even when the safety valves 241 and 242 are not automatically opened, the safety vent line 24a , 24b) can realize gas sensing.

However, in the case of points G and H, since the safety vent lines 24a and 24b are branched from the inert gas discharge lines 23a and 23b, the gas detection line 27a corresponding to the points G and H is the inert gas discharge line ( 23a and 23b) and the gas passing through the safety vent lines 24a and 24b may be delivered to the gas detector. Through this, the present embodiment can minimize the penetration portion in the composite dome 10 .

In addition, the inert gas processing unit 20 of the present embodiment may include a configuration for equalizing. Equalizing is to implement pressure equalization of the storage space 11 and the primary insulating space 12 when leakage occurs in the primary barrier.

When gas leaks from the storage space 11 to the primary insulating space 12 , the storage space 11 is managed at a pressure higher than atmospheric pressure, and the primary insulating space 12 is generally at a lower pressure than the storage space 11 . is managed, there is a risk that the leaked gas flowing into the primary insulating space 12 forms a higher liquid level compared to the storage space 11, and is delivered onto the deck where the crew members are located through the complex dome 10.

Therefore, in this embodiment, when detecting a leak in the primary barrier, the pressure of the primary insulating space 12 and the pressure of the storage space 11 are equally matched, and the leaking gas flowing into the primary insulating space 12 is It suppresses transmission to the deck via the composite dome (10).

To this end, the inert gas processing unit 20 may include a connection end 28a to which an equalizing line is connected. The connecting end 28a is provided in the inert gas supply line 22 and the inert gas outlet lines 23a and 23b, respectively, and the equalizing line is connected to the connecting end 28a and communicates with the storage space 11. Can be provided. have. Therefore, when the equalizing line is connected to the connection end 28a of the inert gas supply line 22 or the like, the primary insulating space 12 may communicate with the storage space 11 .

Specifically, in the drawing, the inert gas supply line 22 connected to the L point is provided with a first connection end 28a, and the inert gas discharge lines 23a and 23b connected to the G point are provided with a second connection end 28b. can be

At this time, the equalizing line communicates with the storage space 11 while being connected to the first connecting end 28a and the second connecting end 28b, and a plurality of points communicating with the primary insulating space 12 in the composite dome 10 are While communicating with the storage space 11 , the internal pressure of the primary insulating space 12 may be balanced with the pressure of the storage space 11 .

However, in a state in which the liquefied gas is normally stored, all of the connection ends 28a are maintained in a closed state, and the storage space 11 and the primary insulating space 12 may be isolated. That is, the equalizing line is a configuration that can be added to the connection terminal 28a in case of an emergency, and is not always provided in the connection terminal 28a.

An additional line 29 may be branched from the inert gas supply line 22 included in the inert gas processing unit 20 . The additional line 29 supplies the inert gas delivered from the inert gas supply unit 21 to various demanders on the ship, and implements purging of various lines and the like, and is provided for direct venting of the inert gas, etc. can be

As such, the present embodiment does not separately include a liquefied gas dome and a boil-off gas dome, but a composite dome 10 to process both liquefied gas and boil-off gas, but primary insulation in the composite dome 10 By effectively arranging lines for implementing supply/discharge/safety venting/sensing of inert gas in the space 12 and the secondary insulating space 13 , it is possible to ensure safe liquefied gas transport.

Although the present invention has been described in detail through specific examples, this is for the purpose of describing the present invention in detail, and the present invention is not limited thereto, and by those of ordinary skill in the art within the technical spirit of the present invention. It will be clear that the transformation or improvement is possible.

Furthermore, although each drawing has been described separately for convenience of description, it is also possible to design to implement a new embodiment by merging the embodiments described in each drawing.

All simple modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be made clear by the appended claims.

1: gas treatment system 10: composite dome
11: Storage space 12: Primary insulation space
13: secondary insulation space 20: inert gas processing unit
21: inert gas supply unit 22: inert gas supply line
22a: first inert gas supply line 22b: second inert gas supply line
221: first inert gas supply valve 222: second inert gas supply valve
23a: first inert gas discharge line 23b: second inert gas discharge line
231: first inert gas discharge valve 232: first inert gas discharge valve
24a: first safety vent line 24b: second safety vent line
241: first safety valve 242: second safety valve
25a: first pilot line 25b: second pilot line
26: vent mast 27a: first gas detection line
27b: second gas sensing line 28a: first connection end
28b: second connection terminal 29: additional line
100: liquefied gas storage tank 110: wall
111: primary barrier 112: primary insulating wall
113: secondary barrier 114: secondary insulation wall
115: opening 116: protrusion
300: dome coaming 310: exterior wall
320: upper wall 330: support
340: step removing means 400: dome cover
410: frame 420: insulation
430: liquefied gas discharge line 431: emergency treatment line
432: cable pipe 440: liquefied gas loading line
441: top peeling line 450: safety vent line
451: pilot line 460: boil-off gas discharge line
471: maintenance opening 472: equipment through opening
480: line fixing portion 481: insulation member
482: circumferential member 483: washer member
484: finishing member 485: rib bracket

Claims (5)

A primary barrier made of metal, a primary insulating wall disposed outside the primary barrier, a secondary barrier provided outside the primary insulating wall, and secondary thermal insulation disposed outside the secondary barrier A storage space for accommodating liquefied gas is formed surrounded by a wall including a wall, and a primary thermal insulation space including the primary thermal insulation wall is formed between the primary barrier and the secondary barrier, and Forming a secondary thermal insulation space including the secondary thermal insulation wall on the outside,
and a dome provided so that a liquefied gas line passes through the wall forming the upper surface of the storage space for the inflow and outflow of liquefied gas
The dome is
a dome cover through which the liquefied gas line passes; and
It is provided on the upper wall of the storage space, the dome cover is seated and fixed, and includes a dome coaming for closing the primary insulating space and the secondary insulating space,
By providing a boil-off gas discharge line for discharge of boil-off gas generated in the storage space together with the liquefied gas line on the dome cover, it is characterized in that it is provided as a composite dome through which both liquefied gas and boil-off gas flow in and out Liquefied gas storage tank. According to claim 1, wherein the dome cover,
A liquefied gas storage tank, comprising a liquefied gas discharge line and a liquefied gas loading line for the inflow and outflow of liquefied gas, and a boil-off gas discharge line for discharging boil-off gas. According to claim 2, The dome cover,
At least one pair of the liquefied gas discharge line and the liquefied gas loading line are arranged to form a triangle, and the boil-off gas discharge line is arranged outside the triangle formed by the liquefied gas discharge line and the liquefied gas loading line. liquefied gas storage tank. According to claim 2, wherein the boil-off gas discharge line,
Liquefied gas storage tank, characterized in that disposed adjacent to the liquefied gas loading line. A ship, characterized in that it has the liquefied gas storage tank according to any one of claims 1 to 4.

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