KR20220038360A - Sealed Insulated Tanks for Floating Structures - Google Patents

Abstract

The present invention relates to a tank integrated into an offshore structure, the tank having a tank wall, said tank wall comprising: A heat insulating barrier (2, 5) comprising a plurality of heat insulating panels (7, 8) in the shape of a parallelepiped fixed to the supporting structure (3) of the offshore structure and juxtaposed in the longitudinal direction (L), each heat insulating panel (7) , 8 ) having an upper surface 13 forming a support surface 13 , wherein two or more heat-insulating panels 7 , 8 juxtaposed to each other in the longitudinal direction L are formed by an interpanel space 15 , 21 . spaced apart, the insulating barriers (2, 5) having a joint seam (16) disposed in the interpanel space (15, 21) to fill the interpanel space (15, 21) in the longitudinal direction (L); insulating barriers (2, 5); a sealing membrane (4, 6) having a flat strip (11) extending in the longitudinal direction (L) on the upper surface (13) and on at least one joint seam (16), wherein at least one said joint seam ( 16) means that the upper surface 17 of the joint seam 16 is located below the supporting surface 13 in the thickness direction E of the tank wall 1, and the upper surface 17 of the joint seam 16 is is such that in use it is spaced apart from the support surface 13 in the thickness direction by a non-zero distance 24 that is less than the maximum separation distance.

Description

Sealed Insulated Tanks for Floating Structures

The present invention relates to the field of sealed insulated tanks with membranes. In particular, the present invention relates to a tank for transporting, for example, liquefied pomegranate gas (LPG) having a temperature between -50 °C and 0 °C or liquefied natural gas (LNG) at about -162 °C at atmospheric pressure; to the field of sealed insulated tanks for storing and/or transporting liquefied gases at such low temperatures. Thus, the tank may be intended to transport liquefied gas or to contain liquefied gas serving as fuel for the propulsion of offshore structures.

Document FR2968284 discloses a sealed insulated tank for the storage of liquefied gas integrated into the supporting structure of an offshore structure, such as the hull of a ship. The tank has a plurality of tank walls connected to each other, each tank wall having two insulating barriers and two sealing membranes adapted to be fixed to a supporting structure.

Each insulating barrier of such a tank comprises a plurality of insulating panels in the shape of a parallelepiped juxtaposed in the longitudinal and transverse directions. With the aid of the upper surface, the insulating panel forms a supporting surface for the sealing membrane.

However, for design and assembly reasons, the insulating panels are spaced apart from each other in the longitudinal direction by a space called the interpanel space. For this reason, the sealing membrane in the interpanel space region is not supported by the supporting surface but by the filler material arranged in the interpanel space.

It has now been found that the beam of a vessel comprising such a tank is deflected in the longitudinal direction of the vessel due to various factors. For example, bending of a ship's beam is caused by the movement of the hull from a dry dock to a floating state or a change in hull temperature between production and in-service temperatures or forces applied to the ship by re-expansion.

The invention proceeds from the hypothesis that during this bending phenomenon, the sealing membrane may be subjected to longitudinal compressive stresses on some walls of the tank and thus buckle in areas not supported by the supporting surfaces, for example in the interpanel space. .

The idea behind the present invention is to improve the support of the sealing membrane in order to prevent or control the buckling phenomenon during compression of the sealing membrane.

According to one embodiment, the present invention provides a sealed and insulated tank for storage of liquefied gas incorporated in an offshore structure, the tank having a tank wall, the tank wall comprising:

- an insulating barrier comprising a plurality of parallelepiped-shaped insulating panels fixed to a supporting structure of an offshore structure and longitudinally juxtaposed, each of said insulating panels having an upper surface forming a supporting surface, and longitudinally juxtaposed with each other; an insulating barrier comprising joint shims in the interpanel space in such a way that the two or more insulating panels formed are spaced apart by an interpanel space, the insulating barrier filling the interpanel space in a longitudinal direction;

- a sealing membrane overlying the thermal insulation barrier and having a planar strip extending longitudinally over the supporting surfaces of the several juxtaposed thermal insulation panels and at least one joint seam disposed between the juxtaposed thermal insulation panels;

at least one said joint seam is such that an upper surface of said joint seam is positioned below a support surface in the thickness direction of the tank wall and wherein said upper surface of said joint seam is a support surface in thickness direction by a non-zero distance less than a maximum separation distance in use. The sealing membrane, which is configured to be spaced apart from the , can be changed out of the interpanel space without reaching the elastic limit.

Due to this feature, the joint seam makes it possible to fill the insulating barrier without preventing slight buckling of the sealing membrane in the interpanel space, and with the aid of the upper surface in the buckling of the sealing membrane in the interpanel space the sealing membrane serves as a support for Indeed, in response to bending of the supporting structure in the longitudinal direction, the sealing membrane becomes actuated in compression, and therefore it is desirable to support the sealing membrane in the entire longitudinal direction or at least limit the permissible deformation values. Whether this is limited to the maximum separation distance in a given use such that the distance in the thickness direction between the upper surface of the joint seam and the supporting surface of the insulating barrier can be changed by buckling in the interpanel space without the sealing membrane reaching its elastic limit. is the reason for

The distance in the thickness direction between the upper surface of the joint seam and the supporting surface of the insulating barrier is understood as the distance between the point of the upper surface of the joint seam furthest from the supporting surface in the thickness direction and the point of the supporting surface of the insulating barrier.

The distance between the upper surface of the joint seam and the supporting surface in the thickness direction is when the tank is completely or partially filled with liquefied gas, then the tank interior is at cryogenic temperature, and/or the tank contains no liquefied gas The case is taken into account when the inside of the tank is at approximately ambient temperature during production, for example.

Depending on the material from which the joint seam and the insulating panel are made, the thickness-wise distance between the upper surface of the joint seam and the supporting surface of the insulating barrier is variable depending on the temperature change and thus the phenomenon of thermal contraction or expansion. For this reason, it is advantageous for this distance to be smaller than the maximum separation distance in use, which represents the maximum value of the distance taking the temperature change into account.

Thus, if cooling of the tank causes greater shrinkage of the joint seam than the insulating panels, the distance between the top surfaces will increase during cooling. In this case, the maximum separation distance in use should be calculated as the maximum separation distance for the tank during cooling, ie with liquefied gas loaded. In this case, the elastic limit of the sealing membrane when cold has to be taken into account. To this end, when cooling, the maximum separation distance of the tank as a function of the length separating the space between the two panels, the level of deformation of the hull, the longitudinal dimension of the space between the panels, the number of spaces between the panels of the insulating barrier, the material and dimensions of the sealing membrane. Calculated prior to manufacture.

Conversely, if cooling of the tank causes greater shrinkage of the insulation panel than the joint seam, the distance between the upper surfaces during cooling will decrease. In this case, the maximum separation distance in use shall be calculated as the maximum separation distance when hot, ie the maximum separation distance for tanks at ambient temperature. In this case, the elastic limit of the sealing membrane when hot has to be taken into account. If hot, the maximum separation distance can be calculated using the same parameters. It is also possible to calculate the maximum separation distance when hot as a function of the maximum separation distance when cold, the height of the insulation barrier, the average temperature change in the interpanel space between the ambient temperature and the loading temperature in the liquefied state, the joint seam and the coefficient of thermal expansion of the insulation panel. there is.

According to embodiments, such tanks may have one or more of the following characteristics.

According to one embodiment, the distance between the support surface and the upper surface of the joint seam in the thickness direction is at least 0.5 mm and is less than the maximum separation distance in use.

Thus, this distance allows the membrane to release possible compressive stresses with controlled buckling in all situations. This inequality between the distance and the various boundaries of the inequality is observed when the tank is completely or partially filled with liquefied gas and the inside of the tank is cryogenic, there is no liquefied gas in the tank and the temperature of the inner tank is approx. Observed when at ambient temperature.

According to one embodiment, all joint seams are supported in thickness by a non-zero distance, wherein the upper surface of the joint seam is located below the supporting surface in the thickness direction of the tank wall and said upper surface of the joint seam is less than the maximum separation distance in use. spaced from the surface, and in this way, the sealing membrane can be deformed by buckling in the interpanel space without reaching its elastic limit.

According to one embodiment, the upper surface of the joint seam is planar.

According to one embodiment, the upper surface of the joint seam is concavely curved.

According to one embodiment, the upper surface of the joint seam forms at least one concave sinusoidal arch.

Thus, the sealing membrane is supported by the curvature of the upper surface of the joint seam over the entire interpanel space, taking into account the curvature formed by the membrane upon buckling.

According to one embodiment, it is preferred that the curved upper surface of the joint seam comprises a plurality of concavities and convexities directed from the concave concavities and convexities towards the support structure.

Therefore, the upper surface formed by the concavo-convex portion has a minimum curvature while maximizing the length of the curve in the longitudinal direction of the upper surface, and the amplitude-controlled concave-convex portion causes the membrane to be completely relaxed in a compressed state, It is prevented from exceeding this elastic limit.

According to one embodiment, the curved upper surface of the joint shim comprises an odd number of convexities facing the supporting structure, one of the convexities being located in the middle of the joint shim in the longitudinal direction.

Therefore, the initiation of buckling located at the center of the interpanel space will be located at the central concavo-convex portion, which makes it possible to better support and guide the buckling of the sealing membrane.

According to one embodiment, the upper surface of the joint seam is continuous in the longitudinal direction.

Thus, the continuity of the upper surface makes it possible to avoid situations in which the sealing membrane is not supported in the longitudinal region and/or the sealing membrane is subjected to excessive stress due to too large surface irregularities.

According to an embodiment, the upper surface of the joint seam has at least one discontinuity in the longitudinal direction, the dimension of the discontinuity in the longitudinal direction being smaller than the critical length of Euler buckling of the sealing membrane.

According to one embodiment, the maximum separation distance in a given use is 2.5 mm or less.

Therefore, assuming that the longitudinal dimension of the tank is 40 m, the sealing membrane is made of Invar® with a thickness of 0.7 mm, and the longitudinal dimension of the interpanel space is 60 mm, the maximum separation distance during use will reach the elastic limit of the sealing membrane. It is advantageous to be less than 2.5 mm to prevent

According to one embodiment, the joint seam is made of high-density glass wool or rock wool, or an insulating foam, preferably a foam reinforced with fibers, for example glass fibers such as polyurethane foam, PVC foam, It is formed from a material selected from vinyl foam, expanded polystyrene, glass foam, and the like.

According to one embodiment, the joint seam is made of glass wool or rock wool having a density of 50 kg.m-3 or more. The coefficient of thermal expansion of glass wool or rock wool is between 6x10 ^-6 K ^-1 and 10x10 ^-6 K ^-1 .

According to one embodiment, the joint seam is made of a polymer foam reinforced with fibers, the fibers being oriented substantially in the thickness direction of the tank wall, for example a glass fiber reinforced polyurethane foam. The coefficient of thermal expansion of the glass fiber reinforced polyurethane foam is on the order of 20x10 ^-6 K ^-1 .

According to one embodiment, the joint seam is made of PVC foam. The coefficient of thermal expansion of PVC foam is from 35x10 ^-6 K ^-1 to 40x10 ^-6 K ^-1 .

According to one embodiment, the compressive modulus of the joint seam in the thickness direction is at least 10 kPa.

According to one embodiment, the coefficient of thermal expansion of the joint seam is greater than or equal to the coefficient of thermal expansion of the insulating panel.

Due to this feature, during the cooling of the tank wall after the liquefied gas is loaded, this relationship between the coefficient of thermal expansion makes it possible to avoid a situation in which the joint seam protrudes from the supporting surface into the inside of the tank, which can damage the sealing membrane. . In this case, the maximum separation distance during use is equal to the maximum separation distance during cooling.

According to one embodiment, the thermal expansion coefficient of the joint seam is 45x10 ^-6 K ^-1 or less, preferably 40x10 ^-6 K ^-1 or less, more preferably 6x10 ^-6 K ^-1 to 40x10 ^-6 K ^-1 .

According to one embodiment, the at least two juxtaposed thermal insulation panels comprise a chamfered edge adjacent the joint seam, the chamfered edge being located on the upper surface of the juxtaposed thermal insulation panel.

Thus, the chamfered edge of the insulation panel makes it possible to reduce the risk of damage during buckling of the membrane compared to when the parallelepiped insulation panel has sharp ridges with an angle of 90°.

According to one embodiment, one or each of the insulating panels or part of the insulating panel comprises a side wall adjacent to one of the joint seams, the supporting element projecting from the side wall in the direction of the joint seam and disposed above the supporting element in the thickness direction. an upper portion of the joint shim, wherein the support element is configured to form a support surface for the upper portion of the joint shim.

According to one embodiment, the support element is located in the upper part of the side wall, ie in the part located between the upper surface and the central plane of the insulating panel in thickness direction.

The support element thus makes it possible to support the joint seam at an intermediate level so as to limit differential thermal shrinkage for the insulating panel to which the support element is fastened, and in this way the joint seam further entrains the insulating panel during shrinkage of the insulating panel. will do

According to one embodiment, the planar strip extends longitudinally from the tank transverse wall to the tank transverse wall.

According to an embodiment, the sealing membrane is a longitudinally tensioned membrane, ie a membrane without elements that make it possible to absorb longitudinal strains, which elements can be, for example, irregularities.

According to one embodiment, the insulating panel is juxtaposed in a longitudinal direction and in a transverse direction perpendicular to the longitudinal direction, the sealing membrane has a plurality of parallel strakes, the strakes forming the planar strips and insulating the insulating barrier a planar central portion overlying the upper surface of the panel and two protruding edges disposed on opposite sides of the planar central portion in the transverse direction and projecting toward the interior of the tank with respect to the central portion, the strake forming an inflatable bellows They are welded to each other in a sealing manner at the protruding edges and juxtaposed in a repeated pattern.

According to one embodiment, the insulation panel comprises at least one groove in the upper surface of the insulation panel, the sealing membrane being fixed in the groove and protruding of two adjacent strakes to hold the sealing membrane on the insulation barrier. and a stator wing welded to the edge.

According to an embodiment, the sealing membrane is a secondary sealing membrane, the thermal insulation barrier is a secondary thermal insulation barrier, and the tank wall is a secondary thermal insulation barrier, a secondary sealing membrane, in a thickness direction from the outside of the tank to the interior; a primary insulating barrier overlying the secondary sealing membrane and a primary sealing membrane overlying the primary insulating barrier and brought into contact with the liquid gas.

According to one embodiment, the sealing membrane is made of Invar174®, ie an alloy of iron and nickel having a coefficient of expansion of generally 1.2x10 ^-6 to 2x10 ^-6 K ^-1 .

According to an embodiment, the sealing membrane is a primary sealing membrane, the thermal insulation barrier is a primary thermal insulation barrier, and the tank wall is a secondary thermal insulation barrier fixed to the support structure in a thickness direction from the outside of the tank to the interior. , a secondary sealing membrane overlying the secondary insulating barrier, a primary insulating barrier overlying on the secondary sealing membrane and secured to a supporting structure by the secondary insulating barrier, and overlying the primary insulating barrier; and a primary sealing membrane brought into contact with the liquefied gas.

According to one embodiment, the sealing membrane is the only sealing membrane of the tank wall and the insulating barrier is the only insulating barrier of the tank wall.

According to an embodiment, the inter-panel space is a secondary inter-panel space, the thermal insulation panel is a secondary thermal insulation panel, and the primary thermal insulation barrier is a plurality of primary insulation in a parallelepiped shape juxtaposed in the longitudinal and transverse directions. It is formed of a panel, and the two juxtaposed primary insulating panels are spaced apart from each other by the primary interpanel space, and the dimension of the primary interpanel space in the longitudinal direction is greater than the dimension of the secondary interpanel space in the longitudinal direction. small.

According to one embodiment, the secondary interpanel spacing has a longitudinal dimension equal to 50 to 70 mm, preferably 60 mm.

According to one embodiment, the primary interpanel spacing has a longitudinal dimension equal to 5 to 20 mm, preferably 8 mm.

A longitudinal dimension is understood as a dimension in the longitudinal direction.

According to one embodiment, the larger dimension of the marine structure is oriented in the longitudinal direction.

According to one embodiment, the tank wall is a floor wall or a ceiling wall.

These tanks are installed in offshore, offshore or deep sea structures, particularly liquefied gas carriers, offshore storage and regasification units (FSRUs), remote offshore production and storage units (FPSOs), and the like. These tanks can also be used as fuel tanks on all types of ships.

According to one embodiment, the present invention provides a method for manufacturing a sealed and insulated tank, the method comprising:

- arranging parallelepiped-shaped insulating panels juxtaposed in the longitudinal direction and transversely perpendicular to the longitudinal direction in such a way as to form an insulating barrier, each insulating panel having an upper surface forming a supporting surface, wherein in the longitudinal direction arranging thermal insulation panels, wherein at least two thermal insulation juxtaposed to each other are spaced apart by an inter-panel space;

- disposing a joint seam in the at least one interpanel space to fill the interpanel space in the longitudinal direction, the joint seam being configured such that an upper surface of the joint seam is located below the supporting surface in the thickness direction of the tank wall at ambient temperature placing a;

- ascertaining that the upper surface of the joint seam is spaced from the supporting surface in the thickness direction of the tank wall by a distance less than a predetermined maximum separation distance when hot at ambient temperature;

- fixing the sealing membrane to the supporting surface of the insulating barrier.

Due to this feature, during tank production, the upper surface of the joint seam in the thickness direction to ensure that the joint seam plays its role as a support for the sealing membrane in case the sealing membrane buckles in response to the curvature of the supporting structure in the longitudinal direction. It becomes possible to verify the distance between and the support surface.

According to one embodiment, the verifying step is carried out with the aid of a template arranged in the interpanel space above the joint seam.

According to an embodiment, ECmax, which is the maximum separation distance when hot, is determined by the following equation.

, 여기서 EFmax는 차가울 때의 소정의 최대 이격 거리, h는 단열 패널의 높이, α_panel은 단열 패널의 열팽창 계수, α_shim은 조인트 시임의 열 팽창 계수, ΔT는 탱크가 패널간 공간에서 탱크가 액화 가스로 적재된 상태일 때의 온도와 주위 온도 사이의 온도 변화를 나타낸다.

, where EFmax is the predetermined maximum separation distance when cold, h is the height of the insulating panel, α _panel is the thermal expansion coefficient of the insulating panel, α _shim is the thermal expansion coefficient of the joint seam, ΔT is the tank liquefying the tank in the interpanel space It represents the change in temperature between the gas-loaded state and the ambient temperature.

According to one embodiment, the maximum separation distance during use is 2.5 mm or less, and the maximum separation distance during use is a predetermined maximum separation distance when cooled relative to a tank loaded with liquefied gas and a predetermined maximum separation when the tank is hot at ambient temperature. It corresponds to the maximum value between the distances.

Therefore, assuming that the inter-panel spacing is 1 meter apart, the sealing membrane is made of Invar® with a thickness of 0.7 mm, the longitudinal dimension of the inter-panel spacing is 60 mm, and the maximum separation distance during use reaches the elastic limit of the sealing membrane. It is preferable to be less than 2.5 mm to prevent it.

According to one embodiment, the present invention makes it possible to use a vessel for transporting cold liquid products having a double hull and a tank as described above arranged in the double hull.

According to one embodiment, the present invention provides the above-described ship, an insulated pipeline arranged to connect a tank installed in the hull of the ship to an offshore or onshore storage facility, and an insulated pipeline between the offshore or onshore storage facility and the tank of the ship. Allows use of a conveying system for cold liquid product comprising a pump for driving a flow of cold liquid product.

According to one embodiment, the present invention provides a method for loading or unloading such a vessel, in which the cold liquid product is conveyed via an insulated pipeline between an offshore or onshore storage facility and the vessel's tank.

BRIEF DESCRIPTION OF THE DRAWINGS The purpose, details, features and effects of the present invention will become apparent through the following description of a number of embodiments of the present invention provided in a non-limiting manner with reference to the accompanying drawings.
1 is a cut-away perspective view of a tank wall;
FIG. 2 is a detailed view of part II of FIG. 1 , showing the interpanel space of the tank wall according to the first embodiment after buckling of the sealing membrane; FIG.
3 is a schematic front view of an inter-panel space according to the second embodiment.
4 is a schematic front view of an inter-panel space according to a third embodiment.
5 is a schematic front view of an inter-panel space according to the fourth embodiment.
6 is a schematic cutaway view of a tank of a liquefied gas carrier and a terminal for loading/unloading the tank;

A tank wall to be described later is fixed to a support structure of an offshore structure such as a ship. By convention, "above" or "above" or "above" refers to a location closer to the interior of the tank, and "below" or "below" or "below" refers to a location closer to the supporting structure, independent of the orientation of the tank wall with respect to the Earth's gravitational field. indicates the location.

1 shows the multilayer structure of a wall 1 of a sealed and insulated tank for storage of a liquefied fluid, for example liquefied natural gas (LNG). Each wall 1 of the tank has, from the outside to the inside of the tank in the thickness direction E, a secondary insulating barrier 2 attached to the support structure 3 , a secondary seal lying on said secondary insulating barrier 2 . Membrane (4), a primary insulating barrier (5) overlying against said secondary sealing membrane (4), and a primary sealing membrane overlying a primary insulating barrier (5) adapted to come into contact with the liquefied natural gas contained in the tank (6) is included in succession.

Said support structure 3 may in particular be formed by the hull or double hull of the ship. The support structure 3 comprises a plurality of walls defining the general shape of the tank, which is generally polyhedral.

Said secondary insulating barrier 2 has a plurality of secondary insulating panels 7 which are fixed to the supporting structure 3 by means of fastening devices 9 . The secondary insulation panels 7 have a general parallelepiped shape and are arranged in parallel rows in the longitudinal direction (L) and the transverse direction (T). In each row extending in the longitudinal direction L, the secondary insulating panels 7 are spaced apart from each other by a secondary interpanel space 15 .

The secondary sealing membrane 4 comprises a continuous sheet of metal strakes 10 with protruding edges. The strake 10 thus has a planar central portion 11 lying on the upper surface 13 of the primary insulating panel 7 of the secondary thermal insulation barrier 2 , the planar central portion in the transverse direction T It has two raised edges 12 disposed on either side of (11) and projecting toward the interior of the tank with respect to the central portion (11). The strakes 10 are welded by raised edges 12 on parallel weld supports fixed to grooves 22 formed in the upper surface 13 of the secondary insulating panel 7 . The strake 10 is made, for example, of Invar®, an iron and nickel alloy with a coefficient of expansion generally between 1.2x10 ^-6 and 2x10 ^-6 K ^-1 .

Said primary insulating barrier 5 has a plurality of primary insulating panels 8 which are fixed to the supporting structure 3 by means of the aforementioned fastening devices 9 . The primary insulating panel 8 has a general parallelepiped shape. Further, the primary insulating panel is substantially identical to the dimensions of the secondary insulating panel 7 except that the thickness in the thickness direction E of the tank wall 1 may be different, in particular may be smaller. have the same dimensions. In each row extending in the longitudinal direction L, the primary insulating panels 8 are spaced apart from each other by the primary interpanel space 21 . Each primary thermal insulation panel 8 is arranged in line with one of the secondary thermal insulation panels 7 in the thickness direction E of the tank wall 1 . In an embodiment not shown, the primary insulating panels 8 are positioned in staggered rows with respect to the secondary insulating panels 7 .

The secondary insulation panel (7) and the primary insulation panel (8) have a bottom plate, a cover plate and a load-bearing partition extending in the thickness direction of the tank wall (1) between the bottom plate and the cover plate, perlite; Manufactured in the form of a box delimiting a number of compartments filled with insulating packing such as glass wool or rock wool. In another embodiment, the secondary thermal insulation panel 7 and the primary thermal insulation panel 8 comprise a bottom plate, a cover plate and optionally an intermediate plate, for example made of plywood. The secondary insulating panel 7 and the primary insulating panel 8 also include one or more layers of insulating polymer foam sandwiched between and adhesively bonded to a bottom plate, a cover plate and an optional intermediate plate. The insulating polymer foam may in particular be a polyurethane-based foam optionally reinforced with fibers.

In another embodiment, the secondary insulating barrier 2 and/or the primary insulating barrier 5 has at least two different types of structures, for example 2 having two aforementioned structures depending on the area where they are installed in the tank. secondary thermal insulation panels 7 and/or primary thermal insulation panels 8 having at least two different types.

The primary sealing membrane 6 comprises a continuous sheet of metal strakes 10 having raised edges of the same kind as the strakes 10 of the secondary sealing membrane 4 . The strakes 10 of the primary sealing membrane 6 are welded by raised edges 12 on parallel weld supports fixed in grooves formed in the upper surface of the primary insulating panel 8 . Although the primary sealing membrane 6 produced with the aid of metal strakes 10 is described, the primary sealing membrane 6 may be produced by other techniques. In another embodiment, not shown, the primary sealing membrane 6 can be produced with the aid of a corrugated metal sheet, for example as described in document FR2691520.

As shown in FIG. 1 , the fixing devices 9 are located at the four corners of the primary insulating panel 8 and the secondary insulating panel 7 . The stack, each composed of the secondary insulating panel 7 and the primary insulating panel 8 , is fixed to the supporting structure 3 by means of four fixing devices 9 . Furthermore, each fastening device 9 cooperates with the corners of four adjacent secondary thermal insulation panels 7 and with the corners of four adjacent primary thermal insulation panels 8 .

The secondary insulating barrier 2 includes joint seams 16 disposed in each of the secondary interpanel spaces 15 to fill the secondary interpanel spaces 15 in the longitudinal direction L. These joint seams 16 and secondary interpanel spaces 15 are shown in greater detail in FIGS.

As described above, in response to bending of the beam of the offshore structure and thus bending of the structure supporting the tank in the longitudinal direction, the sealing membranes 4 , 6 are pressed into at least the ceiling wall or the bottom wall of the tank. get it to work In order to prevent excessive buckling of the sealing membrane 4 , 6 from leading to punctiform plasticization, it has been found desirable to ensure sufficient support of the entire sealing membrane 4 , 6 along the longitudinal direction. .

In the tank wall shown in FIG. 2 , the secondary interpanel space 15 is much larger than the primary interpanel space 21 in the longitudinal direction. For this reason, in the remainder of the description, the behavior of the secondary sealing membrane 4 and the secondary insulating barrier 2 will be described in more detail. In fact, the risk of buckling is greater in the secondary arrangement in terms of the difference in size between the secondary interpanel space 15 and the primary interpanel space 21 . It should be noted, however, that the present invention can also be realized in the primary insulating barrier 5 , whether supporting the primary sealing membrane 6 or the secondary sealing membrane 4 .

2 to 5 show several embodiments of a secondary insulating panel 7 and a joint seam 16 . In each of these embodiments, the joint seam 16 has an upper surface 17 having the function of supporting the secondary sealing membrane 4 in particular when the secondary sealing membrane is deformed by buckling. In addition, the joint seam 16 is configured such that the upper surface 17 is located below the supporting surface 13 of the secondary insulating panel 7 in the thickness direction E, so that the secondary surface 13 is formed on the supporting surface 13 . It does not interfere with disposing the sealing membrane 4 .

Thus, FIG. 2 shows 2 with a joint seam 16 and a secondary sealing panel 7 according to the first embodiment in which the secondary sealing membrane 4 is changed by buckling 22 as a result of compressive stress. The car interpanel space 15 is shown in greater detail.

In the embodiment shown in FIG. 2 , the upper surface 17 of the joint seam 16 is planar and the secondary sealing membrane 4 rests on a part of this upper surface 17 during buckling.

3 shows a second embodiment similar to the first embodiment. However, here the secondary insulating panel 7 comprises a chamfered edge 20 at the support surface 13 adjacent the joint seam 16 . In case of a possible buckling of the secondary sealing membrane 4 , the chamfered edge 20 may be accompanied by a deformation of the secondary sealing membrane 4 in contrast to sharp ridges, such that the ridge and the secondary sealing membrane 4 ) to prevent damage at the point of contact between them.

In the illustrated case, the thermal shrinkage coefficient of the joint seam 16 is greater than that of the secondary insulating panel 7 . Also, this figure shows the distance 23 when hot between the upper surface 17 of the joint seam 16 and the supporting surface 13 of the secondary insulation panel 7, i.e. before the tank is loaded with liquefied gas, Therefore, the distance at the ambient temperature before heat shrinkage due to a significant temperature change occurs, showing that this distance is increased.

The broken line in FIG. 3 schematically shows the thermal contraction phenomenon according to the liquefied gas loading. In practice, significantly lowering the temperature causes the construction material of the secondary insulating panel 7 and joint seam 16 to shrink. In addition, the thermal expansion coefficient of the secondary thermal insulation panel 7 mainly formed of plywood is smaller than the thermal expansion coefficient of the joint seam 16 , so that the secondary thermal insulation panel 7 shrinks less than the joint seam 16 . Thus, it can be seen that the distance 23 at high temperature is shorter than the distance 24 at low temperature after the tank is loaded with liquefied gas.

Thus, the distance when cold 24 is less than or equal to the maximum separation distance when cold, which is predetermined according to the structural parameters of the tank, and the second sealing membrane 4 buckles and changes in the interpanel space without reaching the elastic limit. There is an advantage in that when the pressure stress applied to the secondary sealing membrane 4 is reduced, it is restored to a normal state. In practice, for example, for a tank with a longitudinal dimension of 40 m, the longitudinal dimension of the secondary sealing membrane (4) made of Invar® with a thickness of 0.7 mm and the secondary interpanel space (15) of 60 mm, the maximum clearance when cold The distance is preferably less than 2.5 mm.

numerical example

A plywood box measuring 430 mm in height is used to form the secondary insulation barrier, and joint seams made of glass fiber reinforced polyurethane foam 430 mm high and oriented in the thickness direction of the tank wall are used to form the secondary insulation barrier. Used to fill the space between panels. The top surface of the box is precisely to the height of the top surface of the joint seam when manufactured at ambient temperature, such that the distance in the thickness direction of the tank wall between the top surface of the box and the top surface of the joint seam is zero.

After the liquefied gas is shipped, in terms of the materials used, the joint seam shrinks more than the box of the insulating barrier. This thermal shrinkage results in a clearance of 0.4 mm between the top surface of the joint seam and the top surface of the box at the operating temperature of the secondary insulating barrier (eg, averaging about -50 °C over its thickness). Thus, the secondary sealing membrane can use a controlled space for buckling without reaching the elastic limit at a specific interpanel space level after the tank has cooled.

Thus, in the manufacture of the tank wall 1, there is a step to verify the distance 23 when hot at ambient temperature, the maximum separation distance when cold and the secondary insulation panel 7 and the joint seam ( 16) does not exceed the predetermined maximum separation distance when hot, which is a function of the coefficient of thermal expansion.

4 shows a third embodiment of the secondary interpanel space 15 . In this embodiment, the joint seam 16 has a concavely curved upper surface 17 , so that at least part of the upper surface 17 has the shape of a sinusoidal arch 18 as a whole. Thus, the secondary sealing membrane 4 is 2 compared to the plane by the curvature of the upper surface 17 of the joint seam 16, taking into account the curvature formed by the secondary sealing membrane 4 upon buckling. It is supported in a larger portion of the car interpanel space 15 .

5 shows a fourth embodiment of the secondary interpanel space 15 . In this embodiment, the joint seam has a concave-convex upper surface 17 having a plurality of concavo-convex portions 19 . The concavo-convex portion 19 makes it possible to maximize the length of the curve in the longitudinal direction of the upper surface 17 while having a minimum curvature. Thus, this allows the secondary sealing membrane 4 to deform sufficiently to absorb the compressive stress, while avoiding a situation in which the deformation reaches the critical value of the elastic limit of the material of the secondary sealing membrane 4 .

Referring to FIG. 6 , a cutaway view of a liquefied gas carrier 70 shows a generally prismatic sealed and insulated tank 71 mounted on the double hull 72 of the vessel. The wall of the tank 71 has a primary sealing barrier adapted to come into contact with the LNG contained in the tank, a secondary sealing barrier disposed between the primary sealing barrier and the double hull 72 of the ship, and the primary sealing barrier and 2 and two insulating barriers respectively disposed between the primary sealing barrier and between the secondary sealing barrier and the double hull 72 .

In a manner known per se, the loading/unloading pipelines 73 arranged on the upper deck of the vessel can be connected by suitable connectors to sea or port terminals for transporting cargo of LNG from or to the tanks 71 .

6 shows an example of a marine terminal having an unloading station 75 , an underwater line 76 and an onshore facility 77 . The loading and unloading station 75 is a fixed offshore installation having a movable arm 74 and a riser 78 supporting the movable arm 74 . The movable arm 74 supports a bundle of insulated flexible tubing 79 that can be connected to a loading/unloading pipe 73 . The steerable movable arm 74 is applicable to all sizes of LNG tankers. A connecting line (not shown) extends into the riser 78 . A loading and unloading station 75 allows LNG tankers 70 to be loaded and unloaded from or to an onshore installation 77 . The onshore installation 77 has a liquefied gas storage tank 80 and a connecting line 81 connected to the loading or unloading station 75 by a submersible line 76 . The subsea line 76 allows the delivery of liquefied gas between the loading or unloading station 75 and the onshore facility 77 over a long distance, for example 5 km, to transport the LNG tanker 70 during loading and unloading operations. It makes it possible to keep it at a great distance from the shore.

In order to create the pressure required for the transfer of the liquefied gas, the vessel 70 is equipped with a pump, the onshore facility 77 is equipped with a pump and/or the loading and unloading station 75 is equipped with a pump.

When the tank is completely or partially filled with liquefied gas, various boundaries of the above-mentioned imbalance and imbalance between the distance between the support surface and the upper surface of the joint seam in the thickness direction are observed, the interior of the tank is at cryogenic temperature and / or if the tank does not contain liquefied gas, the inside of the tank is at approximately ambient temperature, for example at the time of manufacture.

While the present invention has been described in connection with several specific embodiments, it is very clear that the present invention is not limited thereto and includes all technical equivalents of the described means and combinations thereof, provided they come within the context of the present invention.

The use of the verbs "have", "comprise" or "have" and their conjugations do not exclude the presence of elements or steps other than those specified in a claim.

Reference signs between parentheses in the claims should not be construed as limiting the claims.

1: wall
2: Secondary Insulation Barrier
3: support structure
4: secondary sealing membrane
5: Primary Insulation Barrier
6: Primary sealing membrane

Claims (26)

A sealed and insulated tank for storing liquefied gas integrated into an offshore structure, wherein the tank has a tank wall (1), wherein the tank wall (1) comprises:
A heat insulating barrier (2, 5) comprising a plurality of heat insulating panels (7, 8) in the shape of a parallelepiped fixed to the supporting structure (3) of the offshore structure and juxtaposed in the longitudinal direction (L), each heat insulating panel (7) , 8 ) having an upper surface 13 forming a support surface 13 , wherein two or more heat-insulating panels 7 , 8 juxtaposed to each other in the longitudinal direction L are formed by an interpanel space 15 , 21 . spaced apart, the insulating barriers (2, 5) having a joint seam (16) disposed in the interpanel space (15, 21) to fill the interpanel space (15, 21) in the longitudinal direction (L); insulating barriers (2, 5);
a sealing membrane (4, 6) overlying the thermal insulation barrier (2, 5), said sealing membrane (4, 6) on the upper surface (13) of the juxtaposed thermal insulation panel (7, 8) and juxtaposed thermal insulation a sealing membrane (4, 6) having a flat strip (11) extending in the longitudinal direction (L) on at least one joint seam (16) disposed between the panels (7, 8);
At least one said joint seam (16) is such that the upper surface (17) of the joint seam (16) is located below the supporting surface (13) in the thickness direction (E) of the tank wall (1), said joint seam (16) the upper surface 17 of which in use is spaced apart from the supporting surface 13 in the thickness direction by a non-zero distance 24 that is less than the maximum separation distance, the sealing membranes 4 and 6 without reaching the elastic limit Sealed insulation tank, characterized in that it can be deformed by buckling in the interpanel space (15, 21). According to claim 1,
The sealed insulating tank, characterized in that the upper surface (17) of the joint seam (16) is flat. According to claim 1,
The sealed insulating tank, characterized in that the upper surface (17) of the joint seam (16) is concavely curved. 4. The method of claim 3,
A hermetically insulated tank, characterized in that the upper surface (17) of the joint seam (16) forms at least one concave sinusoidal arch (18). 5. The method according to claim 3 or 4,
A hermetically insulated tank, characterized in that the curved upper surface (17) of the joint seam (16) comprises a plurality of recesses (19). 6. The method according to any one of claims 1 to 5,
The upper surface 17 of the joint seam 16 has at least one discontinuity in the longitudinal direction L, the dimension of the discontinuity in the longitudinal direction L being the critical length of Euler buckling of the sealing membrane. Sealed insulated tank, characterized in that smaller. 7. The method according to any one of claims 1 to 6,
Sealed insulated tank, characterized in that the maximum separation distance is 2.5 mm or less in predetermined use. 8. The method according to any one of claims 1 to 7,
The joint seam 16 is made of high-density glass wool or rock wool or an insulating foam, preferably a foam reinforced with fibers, for example glass fibers, for example polyurethane foam, PVC foam, vinyl foam. , expanded polystyrene, and a sealed insulating tank, characterized in that it is formed selected from a glass foam. 9. The method according to any one of claims 1 to 8,
The two or more juxtaposed insulating panels (7, 8) comprise a chamfered edge (20) adjacent a joint seam (16), said chamfered edge being the upper surface (13) of the juxtaposed insulating panel (7, 8). Sealed insulated tank, characterized in that located in the. 10. The method according to any one of claims 1 to 9,
Sealed and insulated tank, characterized in that the flat strip (11) extends longitudinally from the transverse tank wall (1) to the opposite transverse tank wall (1). 11. The method according to any one of claims 1 to 10,
The insulating panels (7, 8) are juxtaposed in a longitudinal direction (L) and a transverse direction (T) perpendicular to the longitudinal direction, the sealing membranes (4, 6) having a plurality of parallel strakes (10) However, the straight 10 forms a flat strip and lies on the upper surface 13 of the insulating panel 7 , 8 of the insulating barrier 2 , 5 with a flat central part 11 and the transverse direction T It is disposed on both sides of the flat central part 11 and has two raised edges 12 that protrude toward the inside of the tank with respect to the central part 11, and the strake 11 has a repeating pattern. A sealed insulated tank characterized in that it is juxtaposed with a but sealed welded to each other at the raised edge (12) to form an expansion bellows. 12. The method of claim 11,
The insulating panel (7,8) comprises at least one groove (14) in the upper surface (13) of the insulating panel (7,8), the sealing membrane (4, 6) in the groove (14) Sealing insulation, characterized in that it has fixed wing portions welded to the raised edges (12) of two adjacent strakes (10), thereby retaining the sealing membrane (4, 6) on the insulating barrier (4, 6) Tank. 13. The method according to any one of claims 1 to 12,
The sealing membrane 4 is a secondary sealing membrane 4 , the thermal insulation barrier 2 is a secondary thermal insulation barrier 2 , the tank wall 1 is, in the thickness direction E, from the outside of the tank to the inside furnace, a secondary insulating barrier (2), a secondary sealing membrane (4), a primary insulating barrier (5) overlying the secondary sealing membrane (4) and a liquefied secondary insulating barrier (5) overlying the primary insulating barrier (5) A hermetically insulated tank, characterized in that it has a primary sealing membrane (6) adapted to come into contact with the gas. 14. The method of claim 13,
The inter-panel space 15 is a secondary inter-panel space 15 , the insulating panel is a secondary insulating panel 7 , and the primary insulating barrier 5 is in the longitudinal direction L and the transverse direction T ) is formed of a plurality of primary heat insulating panels 8 of a parallelepiped shape juxtaposed by ), and the two juxtaposed primary insulating panels 8 are spaced apart from each other by a space 21 between the primary panels, and the longitudinal direction ( A sealed and insulated tank, characterized in that the dimension of the primary interpanel space (21) in L) is smaller than the dimension of the secondary interpanel space (15) in the longitudinal direction (L). 15. The method according to any one of claims 1 to 14,
Sealed insulation tank, characterized in that the larger the dimension of the offshore structure is directed toward the longitudinal direction (L). 16. The method according to any one of claims 1 to 15,
Sealed and insulated tank, characterized in that the tank wall (1) is a floor wall or a ceiling wall. 17. The method according to any one of claims 1 to 16,
The insulating panels 7 , 8 comprise a side wall adjacent to one of the joint seams 16 , and a support element projecting from the side wall in the direction of the joint seam 16 , the upper part of the joint seam 16 being Sealed and insulated tank, characterized in that it is positioned above said support element in the thickness direction, said support element being adapted to form a support surface for the upper part of the joint seam (16). 18. The method according to any one of claims 1 to 17,
A sealed and insulated tank, characterized in that the distance in the thickness direction between the upper surface of the joint seam and the supporting surface is 0.5 mm or more and less than the maximum separation distance in use. 19. The method according to any one of claims 1 to 18,
All joint seams are such that the upper surface of the joint seam is positioned below the supporting surface in the thickness direction of the tank wall, the upper surface of the joint seam being the supporting surface in the thickness direction by a non-zero distance less than the maximum separation distance in use. spaced apart from, the sealing membrane being able to deform by buckling in the interpanel space without reaching the elastic limit. A vessel (70) for transporting cold liquid products having a double hull (72) and a tank (71) according to any one of claims 1 to 19 arranged in said double hull. A vessel (70) according to claim 20, an insulated pipeline (73, 79, 76, 81) arranged to connect a tank (71) installed inside the hull of the vessel to an offshore or onshore storage facility, and the insulated pipeline and a pump for driving the flow of the cryogenic liquid product between the marine or onshore storage facility (77) and the tank of the vessel through the In the method of loading or unloading a vessel (70) according to claim 20,
A method of loading or unloading, characterized in that the cooling liquid product is transported via an insulated pipeline (73, 79, 76, 81) between a marine or onshore storage facility (77) and a tank (71) of the vessel. In the manufacturing method of the sealed insulated tank, the method comprising:
- arranging the parallelepiped-shaped insulating panels (7, 8) juxtaposed in the longitudinal direction (L) and the transverse direction (T) perpendicular to the longitudinal direction (L) to form the insulating barriers (2, 5); As such, each thermal insulation panel 7 , 8 has an upper surface forming a supporting surface 13 , wherein two or more thermal insulation panels 7 , 8 juxtaposed to each other in the longitudinal direction L are formed in the interpanel space ( 15, 21), spaced apart by the step of disposing insulating panels;
- disposing a joint seam (16) in one or more interpanel spaces (15, 21) to fill the interpanel space (15, 21) in the longitudinal direction (L), said joint seam (16) being said joint seam arranging the joint seam, such that the upper surface 17 of (16) is located below the support surface (13) in the thickness direction (E) of the tank wall (1) at ambient temperature;
- verification that the upper surface 17 of the joint seam 16 at ambient temperature is spaced from the supporting surface 13 in the thickness direction E of the tank wall 1 by a distance less than a predetermined maximum separation distance when hot to do;
- fixing the sealing membrane (4, 6) to the supporting surface (13) of the insulating barrier (2, 5); 24. The method of claim 23,
The method for manufacturing a sealed and insulated tank, characterized in that the verifying is performed using a template disposed in the interpanel space (15, 21) on the upper part of the joint seam (16). 25. The method of claim 23 or 24,
The maximum separation distance ECmax at high temperature is,

, where EFmax is the predetermined maximum separation distance when cold, h is the height of the insulation panel (7, 8), α _panel is the coefficient of thermal expansion of the insulation panel (7, 8), and α _shim is the joint seam (16) A method of manufacturing a sealed insulated tank, characterized in that the coefficient of thermal expansion, ΔT, is the average temperature change in the interpanel space (15, 21) between the temperature when the tank is loaded with liquefied gas and the ambient temperature. 26. The method of claim 25,
The maximum separation distance in use is 2.5 mm or less, and the maximum separation distance in use is the maximum value between the predetermined maximum separation distance when cold with respect to the tank with liquefied gas loaded and the predetermined maximum separation distance when hot with respect to the tank at ambient temperature. A method of manufacturing a sealed insulated tank, characterized in that it corresponds to.

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