KR20220151182A - Assembly of at least two foam blocks of the thermal insulation slab of the tank - Google Patents

Abstract

Assembly of at least two foam blocks of the thermal insulation slab of the tank.
The present invention relates to an assembly of at least two foam blocks (20, 21), wherein a first foam block and a second foam block have so-called "close" faces, the two blocks (20, 21) having a first Adjacent faces of the first foam block and adjacent faces of the second foam block are adjacent to each other to form a channel having a minimum width (L) in a stable state, and the adjacent face of one of the blocks is adjacent to the upper side of the two opposite sides thereof. If the face and the lower face have a temperature difference of at least 40°C, have at least one shape or cross-section that complements the shape or cross-section of the other adjacent face, and the above-mentioned width (L) of the closure is at least 15% decrease as much as

Description

Assembly of at least two foam blocks of the thermal insulation slab of the tank

The subject of the present invention is an assembly of at least two polymer foam blocks of a thermally insulating slab of a sealed thermally insulating tank having very specific mechanical and thermal properties taking into account the technical characteristics, in particular the specific applications in which they are used. The present invention also relates to a tank incorporating such an assembly, and one or more of these tanks integrated into a membrane structure (also referred to as an integral tank), or in particular to liquefied natural gas (LNG) or liquefied to ships with self-supporting/semi-supporting Type A, B or C tanks for containing extremely cold fluids, referred to as cryogenic, such as Liquefied Petroleum Gas (LPG); and To a vessel equipped with at least one such tank, to a method for loading/unloading such a vessel, and to a transport system for transporting liquid products contained therein. it's about

Finally, the present invention relates to a system and method for preparing a polymer foam block for such an assembly of at least two foam blocks.

The present invention relates more specifically to the foam blocks of an assembly made of fiber-reinforced polyurethane (PUR) and/or polyisocyanurate (PIR) foam blocks mounted on a thermal insulation slab. will be. In the following, the present invention will be described using these PUR and/or PIR foams, but the present invention is not limited to these blocks, whether they are fiber-reinforced (loaded with fibers) or not, a number of polymers. Can be applied to blocks.

The choice of the polymer or polymers used depends on the mechanical and thermal properties which must be as economical to produce as possible, while having very specific mechanical and thermal properties taking into account the specific applications.

Polyurethane (PUR) foam is a cellular insulation made up of microscopic cells that store a gas that can have a low thermal conductivity. PUR foam is used in many applications, such as in the automotive industry as a flexible PUR foam, or in thermal insulation as a rigid PUR foam. The formation of polyurethane-type foams is well known to those skilled in the art. Its formation is a multi-composition between polyols (compounds with at least two hydroxyl groups), polyisocyanates (compounds with at least two isocyanate-NCO functional groups), and blowing agents, also referred to as "blowing agents". It involves a multi-component reaction. This condensation reaction is particularly important for compounds with basic and/or nucleophilic characteristics, such as tertiary amines or metal-carboxylate coordination complexes such as tin or bismuth salts. catalyzed by Polyols commonly used in the manufacture of PUR foams are polyether polyols or polyester polyols. So, numerous compounds are required for the formation of PUR foams.

Polyisocyanurate (PIR) and polyurethane/polyisocyanurate (PUR-PIR) are also used in buildings (construction/remodeling) and have better fire resistance as well as higher resistance to compression than PUR. It has the advantage of providing characteristics. The method for forming these foams is similar to the method for forming PUR foams. Specifically, whether it is a PUR foam, a PIR foam or a PUR-PIR foam that is obtained depends on the isocyanate/polyol ratio.

PUR, PIR and PUR-PIR foams are well known to those skilled in the art. However, since the addition of fibers entails certain technical problems, such as the requirement of good impregnation of the fibers, such foams with a relatively high fiber content, at least locally, do not exist at the present time.

These PUR, PIR and PUR-PIR foams are used in the form of parallelepiped-shaped blocks that are placed within an encasing structure forming a thermally insulating slab. This encasing structure has a hermetic membrane, usually made of stainless steel or invar, and these thermally insulating slabs have at least two slabs of cold liquid contained in the tank, depending on its temperature. Encasing structures may typically be provided.

In the field of technology concerned with the use of these foams for the thermal insulation slabs of tanks, said slabs are subjected to very cold temperatures on the side exposed to the space inside the tank, for example temperatures of the order of -160 °C in the case of LNG. Whereas the space outside the tank, typically the hull of a ship, often has a higher ambient temperature, believed to be around 20°C, at least equal to, or actually much higher than, the temperature of the surrounding air or sea. .

At this time, two adjacent polymer foam blocks are:

- encased in a wooden casing of the plywood or chipboard type, these wooden casings being connected together by joining means, as is the case for example for NO96 ^® tanks; or

- Arranged in the form of a sandwich with top and bottom coatings, these sandwich casings are connected together by a composite mat or fabric, which is usually composed of three layers, for example in the case of MARK III ^® tanks It is like that.

So, there is no direct mechanical or chemical connection between adjacent polymer foam blocks at this time.

Moreover, in the two types of structures mentioned above, two adjacent polymer foam blocks form a space that extends in a straight, typically vertical direction between them when these blocks are installed in a tank, The space must be lined with glass wool or the like to prevent any occurrence of thermosiphoning in particular.

The present invention aims to answer these drawbacks by first solving the problems associated with thermal phenomena that may occur in the space that exists between two adjacent foam blocks.

In this context, the present applicant has succeeded in developing an assembly of polymer foam blocks after various studies and analysis, since the polymer foam blocks have complementary shapes or cross-sections to each other on their facing adjacent faces, the foam block Due to the cooling of the tank containing the cryogenic liquid or the like upon contraction of each of the blocks, at least one region, referred to as the closed region, shows a significant reduction in the width of the channel separating the two blocks.

So, if the blocks are in use with a very different thermal environment between their two upper and lower faces, the upper face is arranged on the inner side of the tank and the lower face is arranged on the outer side of the tank. , the temperature gradient within a block of foam is typically equal to at least 80 °C or even equal to at least 100 °C. Moreover, in addition to this effect of the closure of the channel/duct separating two adjacent blocks, preventing any negative thermal phenomena, this closure constitutes an interlocking means when the faces of the respective blocks are brought into contact. , these two foam blocks will remain close to each other without any bending or tightening.

So, according to one possibility proposed by the present invention, it is now possible to create a direct mechanical connection between two adjacent foam blocks without any attachment elements.

The present invention thus aims to ameliorate the disadvantages of the prior art by proposing a particularly effective solution for industrially obtaining fibre-reinforced PUR/PIR foams having as large as possible dimensions (very), the mechanical properties/thermal The properties are optimal and at least substantially similar between the steady state and its initial state, and the foam block is in a substantially homogeneous thermal environment, while the foam block is in a non-homogeneous thermal environment in its use/service state; The temperature difference between its upper side (the inner side of the tank) and its lower side (the outer side of the tank), taken over the thickness of the block, equals at least 40°C, even equals at least 80°C to 100°C.

Advantageously, with regard to the mode of implementation where there is a mechanical connection between two adjacent blocks, the cost of production of the insulating slab can be reduced thanks to the savings in terms of mounting/assembly time and by eliminating some of the element(s) for the intermediate connection. A significant decrease is possible.

Thus, the present invention relates to an assembly of at least two blocks of a polymeric foam, preferably a polyurethane/polyisocyanurate foam, of a thermally insulating slab of a sealed thermally insulating tank, comprising upper and lower opposite faces as well as lateral faces. The density of at least one foam block is between 30 kg/m ³ and 300 kg/m ³ , and the first and second foam blocks have faces referred to as "adjacent" faces, and the two blocks are adjacent to each other. Arranged, the adjacent lateral faces of the first foam block and the adjacent lateral faces of the second foam block form a channel or duct between them without any mechanical means of attachment, the channel or duct being such that the blocks are stable. Minimum width (L) over at least one of the regions referred to as closed regions of the channel or the duct when in the state, i.e. without a significant temperature difference between its two upper and lower opposite sides With, the adjacent surfaces of the first and second blocks have at least a non-flat or non-linear shape or cross section, and the shape or cross section is respectively relative to the shape or cross section of the other adjacent surface of the first or second foam block. Complementary in nature.

According to the present invention, when said two adjacent blocks are in operation, i.e. the tank is at least partially filled with a cold liquid, so that their two upper and lower opposite sides have a temperature difference of at least 40 °C, preferably at least 80 °C. , the width (L) of the closed portion is reduced by at least 15%.

According to a particularly advantageous aspect of the invention, the channel or duct between the first and second foam blocks is "without any mechanical means of attachment", in other words passing through said duct or channel or between these two blocks. There are no mechanical attachments on the The expression “mechanical attachment” means attachment through a physical element that performs the function of attachment, such as a screw, bolt or the like, or even a connecting rod. For the sake of clarity, these mechanical attachment means differ from chemical attachment means which consist of an adhesive element, such as a chemical adhesive, or an element with an adhesive coating such as a double-sided tape or sticker.

Advantageously, an object of the present invention is to propose a direct means of attachment (including via a compressible material as described below) between two adjacent foam blocks, in particular in the working context of a tank, in a first One that allows protrusions from a polymer foam block to interact with protrusions from a second polymer foam block by interlocking, snap-fitting or even complementarity of shapes.

The expression “cold liquid” refers specifically to cryogenic fluids that are essentially liquid, such as liquefied natural gas (LNG) or liquefied petroleum gas (LPG).

The expression "partially filled" means in relation to the tank and its operating conditions that the tank is filled to at least 20% of its maximum storage capacity. Specifically, the assembly according to the invention is intended for tanks containing cold liquids.

The expression "minimum width (L)" means that this interval (L) represents the minimum interval in the occluded region. Of course, the spacing within the channel or duct at the occlusion site may be constant, in which case the minimum distance (L) is equal to the distance within the channel or duct over the entire occlusion site, but in general the minimum distance (L) is the occlusion site. It consists of the smallest gap that exists in a channel/duct in

The expression "a shape or cross-section substantially complementary to the (three-dimensional) shape or (two-dimensional) cross-section of the other adjacent face" means a solid or quasi-solid adjacent face for each block. means that these two shapes or these two cross-sections can fit together with one side/the other inside to form a part, i.e. the fitting together of the two substantially complementary shapes/sections in the latter case ( fitting) form contiguous parts that are at least 70% solids or even preferably at least 90% solids.

In the following, the invention is shown in the case where the polymer foam of the two blocks consists of a polyurethane/polyisocyanurate foam. Specifically, the present invention is intended to apply, in particular, polymers of this type, but is not limited to these polymers only, and makes them suitable for use in tanks intended to contain cryogenic liquids or the like. Other polymers with mechanical and thermal properties that can be made into polymers are also conceivable. Moreover, according to a preferred embodiment, the two foam blocks are formed or composed of the same polymer foam for obvious production reasons, but it is assumed that these blocks are made of different polymers or at least locally different polymers. It is also possible.

The term "block" according to the present invention is a non-limiting term. A “block” may have any shape and does not have to be cut.

Blocks of polyurethane/polyisocyanurate foam, which are preferably fiber-reinforced, contain up to at least 95%, by weight of the block, advantageously low thermal conductivity gas, polyurethane/polyisocyanurate foam and fibers. It consists of cells that store

The foam block according to the present invention contains only polyurethane (PUR) and/or polyisocyanurate (PIR) foam, preferably fibers with a single property, such as glass fibers, and gases trapped in the cells, and e.g. It consists of as few parts as possible with fillers or other functional adjuvants, the latter to a maximum of 5% by weight or even preferably 2% or more by weight of the foam block according to the invention. (a fiber-reinforced polyurethane/polyisocyanurate foam block then stores at least 98% or up to 99% of the gas, polyurethane/polyisocyanurate foam and fibers by weight of said block). made up of cells). Specifically, the foam block according to the present invention:

- obtained in a single foam preparation operation (mixing reactive components, optionally fillers/auxiliaries with fibers), preferably in a double belt laminator (DBL);

- Obtained by the above preparatory operation supplemented by a cutting operation, which typically corresponds to the cutting of the upper side of the block, in order to obtain a substantially parallelepiped or cube-shaped block.

The present invention is, but not exclusively in this case, a thermally insulating slab comprising a primary layer and a secondary layer with thermal insulation, for example as shown in FIGS. 1 and 2 , typically termed “secondary”. It is intended to be applied where foam blocks are installed in the secondary layer. For such applications, the foam block preferably has a thickness or height of at least twenty-five (25) centimeters (cm) or even more preferably at least 30 cm to 35 cm.

Advantageously, the thermal properties of the fiber-reinforced foam block are at least the same as those of prior art non-fibre-reinforced foam blocks, more precisely the foam block has a thickness E of 30 mW/m.K (milliwatts per meter Kelvin). ; has a thermal conductivity of less than 20 mW/m.K when the upper side of the is at -160°C and the foam block is then in use and is encased in a tank containing LNG.

Thus, fiber-reinforced foam blocks are compatible with use in tanks integrated into a supporting structure, but in accordance with the IGC Code (IMO), ie self-contained for storage and/or transport of very cold liquids such as LNG or LPG. - outer insulation associated with supporting tanks, compatible with use in type A, B or C self-supporting/semi-supporting tanks

Other advantageous features of the present invention are briefly presented below.

Preferably, the minimum width L is reduced by at least 50%.

Advantageously, said channels or ducts have a non-straight path in the cross-sectional plane P.

This non-linear path of channels or ducts that can be made thanks to the present invention makes it possible to reduce or even eliminate any occurrences of thermosiphoning.

So, as can be seen in Figures 6 and 7, which consist of cross-sections along the plane with the thickness of the polymer foam blocks, the path of the duct or channel is not straight, in other words, the path runs through the upper and lower sides. The path is vertical (depending on the thickness of the foam block) and horizontal (over a plane perpendicular to that including the plane spanning the thickness or height of the foam block). or even with some oblique sections.

According to one embodiment, the minimum width L in working conditions is equal to zero, so that at least in the closed area two adjacent blocks are in contact.

So, if there is a direct mechanical connection between adjacent blocks through this closure, which in this case constitutes a means of interlocking or connection between two adjacent blocks, the thermally insulating slab of the sealed thermally insulating tank is cold. In other words, when it is used to contain extremely cold fluids, also referred to as cryogenic, such as liquefied natural gas (LNG) or liquefied petroleum gas (LPG), it is possible to prohibit or prevent separation of adjacent faces.

Preferably, the closure portion is made of a material having a compressive capacity equal to at least 15%, preferably at least 50%, preferably made of glass wool or rock wool or made of elastomer. have. So, the contact between the two polymer blocks is no longer direct, but advantageously takes place through the thinness of this material, which makes it possible to avoid any friction or any abrasion at the point of contact. do. However, this contact between the two polymer blocks is said to be direct, which in this case involves, since the material is quite compressible, so that only a very small thickness of the order of 1 mm or 1 to 2 mm is required for the 2 This is because the gap remains between the blocks, and because the material serves only as a buffer or mechanical stress damper between the two blocks.

According to one possibility proposed by the present invention, at least one foam block, preferably two foam blocks, is made of a fiber-reinforced foam having an average fiber density (T _f ) between 1% and 60% by weight of fibers. preferably the fibers are elongated or continuous, the fibers are made of glass fibers, basalt fibers, hemp fibers or any other organic or inorganic materials, preferably the fibers are made of glass fibers consist of.

The term "fiber(s)" or the expression "fiber reinforcement" refers to the fact that fibers can be of two different types:

- the expression "fiber fabric" per se relates to a clear technical definition known to those skilled in the art, in which the fibers are preferably aligned in at least one direction; In other words, the fibers may be in the form of at least one fiber fabric having at least one preferred fiber direction; or

- on the one hand, the expression "fiber mat" pertains to a clear technical definition known to those skilled in the art, in which the fibers do not have a defined orientation, in other words , that these fibers may be in the form of at least one fibrous mat, with the fibers oriented essentially iso-directionally in the principal plane in which the layers of the mat lie;

means

Advantageously, said substantially complementary shapes or cross-sections consist of a male portion and a female portion, respectively.

According to one possibility proposed by the present invention, the fibers consist of glass fibres, carbon fibres or any other organic or inorganic material, preferably glass fibres, typically polymers, metals, ceramics, natural Fibers, composed of vitreous inorganic or organic natural materials, such as eg hemp or linen, preferably glass fibres.

The expression "tethered fibers" (or "tethered long fibers") refers to any suitable aggregation of fibers, or fibers of a set (fibers adhesively bonded or attached to one another), That is, at least 90% of the fibers considered to be singular or aggregated to form the equivalent of a single fiber by total weight of said fibers have at least five (5) centimeters (cm).

Preferably, the average fiber density (T _f ) is between 2% and 25%, preferably between 6% and 20%.

According to an advantageous embodiment, said complementary shapes or cross-sections have a fiber density greater than the average fiber density (T _f ), preferably between 1.2 T _f and 3 T _f , preferably between 1.4 T _f and 2 T f . It has a fiber density between T _f .

The expression “average fiber density (T _f )” means the fiber density expressed as the weight of fibers relative to the total weight of the fiber-reinforced foam block, without taking into account the variable local (in-block) percentage of these fibers. do.

Preferably, said channels or ducts are made of a thermally insulative material, preferably a glass face.

According to one aspect of the invention, the first and second foam blocks have a substantially parallelepiped or cube shape.

This foam block having the shape of this parallelepiped or cube, in addition to the above-mentioned engaging means, for example in the form of anchors described below or, conversely, in the form of hollow or hollow areas, has one or more local protrusions. However, it can be seen that it can also be provided as a shape having an overall parallelepiped or cube appearance.

So advantageously, the lower side and/or the upper side of the block engages with an interlocking means of a thermal insulation slab (not shown in the attached figures) to attach or anchor a block of foam to the slab. It has anchors that can be, preferably the anchors are made of a material other than foam or fibers.

These anchors are advantageously provided with an L-shaped hooking lug or an L-shaped slot for engagement with a part or element of the thermal insulation slab that surrounds or encloses the fiber-reinforced foam block. )/metal elements with openings (these anchors may be made of plastics/polymers, or composites combining one or more polymers with ceramic and/or metal materials). This part of the thermally insulating slab can consist of a metal-sealing membrane sealing the container made, for example, of stainless steel or manganese steel, a membrane tank (which has the technical function of ensuring sealing against the surrounding environment outside the tank). This is true in the case of membrane tanks or vapor barriers and in the case of self-supporting or semi-supporting Type A, B or C tanks. In one possibility proposed by the present invention, this element or this part of the thermal insulation slab (in the membrane tank) is an anchor for mechanically holding or containing the fiber-reinforced foam block together with the other elements of the thermal insulation slab. It has a notch or something similar intended to allow engagement with any part of. Naturally, these anchors may also have the function of anchoring the foam block to the hull in the case of a membrane tank or to a self-supporting structure in the case of a self-supporting tank of type A, B or C, It can be seen that these anchors are the ones currently on the bottom side of the foam block at that time.

In the context of the present invention, these anchors are of a fiber reinforcement stack, so as to allow them to be positioned on the faces without protruding from said faces once the foam blocks have been prepared/completed. It is at least partially embedded within the fiber reinforcement means corresponding to those constituting the lower or upper layer.

In the following, the terms "upper side" and "lower side" refer to the feeling or direction given to the foam block once the latter is in place within the thermal insulation slab of the tank. Thus, the upper face or portion of the foam block is located on or near the side of the insides of the tank if the thermal insulation slab is placed in the tank, while the lower face or portion of the foam block is located in the tank. located on or towards the outer side of the vessel, that is to say in particular towards the hull of the vessel if the tank is integrated or mounted on the vessel for transporting and/or storing the cryogenic fluid. There is.

So, it can be seen that during the manufacture or preparation of the foam block, the terms or concepts of "upper side" or "lower side" are meaningless, since the foam block has not yet been installed in the thermally insulating slab of the tank. In other words, the foam blocks according to the invention are obtained in such a way that they are obtained in a position opposite to that of the final mounting / assembly in the thermal insulation slab of the tank as they fall off the preparation / production line. It will be possible to prepare as a whole.

Advantageously, according to one feature of the present invention, said width L is between 1 millimeter and 12 millimeters, preferably between 1.5 millimeters and 6 millimeters in steady state.

Advantageously, preferably the density of the fiber-reinforced foam blocks is between 50 kg/m ³ and 250 kg/m ³ , preferably between 90 kg/m ³ and 210 kg/m ³ . For foam blocks used in self-supporting (type B, type C) or semi-supporting (type A) tanks, the density range of the fiber-reinforced foam blocks is preferably between 30 kg/m ³ and 90 kg/m ³ On the other hand, it is noted that for membrane tanks the preferred density range is between 90 kg/m ³ and 210 kg/m ³ .

According to one possibility proposed by the present invention, at least one part of one of the adjacent faces, preferably both of the adjacent faces, has a Young's modulus greater than the Young's modulus of said complementary shape or cross-section of a composite layer or coating. to provide

Advantageously, at least one foam block, preferably both foam blocks, is made of a polyurethane/polyisocyanurate foam, which is advantageously composed of low thermal conductivity gas-storing cells, wherein the gas Advantageously at least 60%, preferably at least 80% of said cells storing ? are parallel to an axis defined by a straight line perpendicular to the lower and/or upper side face(s) of said foam block. It extends along an axis or has an elongated shape.

The expression “gas storage cells” means an enclosure surrounding a gas, preferably of low thermal conductivity, derived from the gas injected during the step of nucleation of the reaction mixture or derived directly or indirectly from a chemical or physical expanding agent. This means that the polyurethane/polyisocyanurate foam has mold cells.

According to one embodiment, the expression “a gas of (advantageously) low thermal conductivity” refers to the chemical blowing agent when it is composed of water and when the agent is referred to as “chemical”, typically carbon dioxide (CO ₂ ). Means a gas derived from a blowing agent by reaction, or, for example, molecular nitrogen (N ₂ ), molecular oxygen (O ₂ ), carbon dioxide, hydrocarbon, chlorofluorocarbon, hydrochlorocarbon, hydrofluorocarbon, hydrochlorofluorocarbon means gases derived from physical blowing agents such as low carbons and mixtures thereof as well as their corresponding alkyl ethers. Physical blowing agents such as molecular nitrogen (N _{2 )} , molecular oxygen (O ₂ ) or CO ₂ are in gaseous form. These gases are dispersed or dissolved in a liquid copolymer mass under high pressure using, for example, a static mixer. When the system is depressurized, the growth and nucleation of bubbles gives rise to a cellular structure.

An elongated or elongated shape can be defined as a shape with elongated length, that is, it has one dimension, its length, greater than the other dimensions (width and thickness).

Advantageously, the fiber-reinforced foam blocks according to the invention are of the organophosphorus type, advantageously triethyl phosphate (TEP), tris(2-chloroisopropyl) phosphate (TCPP), tris(1,3-dichloroisopropyl) ) phosphate (TDCP), tris(2-chloroethyl) phosphate or tris(2,3-dibromopropyl) phosphate or a flame retardant consisting of a mixture thereof, or an inorganic flame retardant type, advantageously red phosphorus, expandable graphite, aluminum A flame retardant consisting of oxide hydrate, antimony trioxide, arsenic oxide, ammonium polyphosphate, calcium sulfate or cyanuric acid derivatives and mixtures thereof in a proportion between 0.1% and 5% by weight.

The invention also relates to a hermetically sealed, thermally insulated tank integrated into a supporting structure, said tank comprising:

- a hermetically sealed thermally insulating tank comprising at least one hermetically sealed metallic membrane composed of a plurality of metallic strakes or metallic plates which may contain corrugations, and at least one thermally insulating barrier adjacent said membrane; a tank integrated into a supporting structure comprising a thermally insulative slab; or

- Type A, B or C tanks according to the definition given by the IGC Code, with at least one thermally insulating slab;

Consists of

The tank according to the invention is characterized in that the thermally insulating slab comprises an assembly of at least two foam blocks, as briefly described above.

The expression "IGC Code" refers to the "International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk" well known to those skilled in the art, such as Type B Tanks and C Tanks mentioned above. Code (International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk)".

The term "membrane tank" is substituted for the expression "integral tank" to name the same category of tanks that fit tankers that at least partially store and/or transport liquefied gas. Note in particular that it can be used in IGC codes. "Membrane tanks" are integrated into a supporting structure, while Type A tanks, B tanks and C tanks are referred to as self-supporting or semi-supporting (specifically Type A).

Finally, the present invention also relates to a vessel for transporting cold liquid products, the vessel having at least a sealed thermally insulating tank and a hull as briefly described above, the hermetic thermally insulating tank comprising: If the tank is a type A, B or C tank according to the definition given by the IGC Code, it is either mounted on the vessel or is housed in the hull.

Furthermore, the present invention relates to an offshore or offshore storage tank for storing liquefied gas, the tank comprising at least one enclosure, preferably made of concrete or the like, and a sealed thermally insulated tank as outlined above. Equipped with, the tank is located in the enclosure. Such storage tanks designated for shore use are typically referred to as "GBS", which stands for "Global Base Storage".

Advantageously, in the case where the tank consists of a tank integrated into the supporting structure, such a vessel has at least one sealed insulative tank as described above, said tank comprising two successive sealed barriers. a primary sealed barrier on one side in contact with the product contained in the tank and on the other side arranged between the primary barrier and a supporting structure consisting preferably of at least a portion of the walls of the vessel. is a secondary hermetic barrier in which the two hermetic barriers are replaced by two thermally insulating barriers or a single thermally insulating barrier positioned between the supporting structure and the primary barrier.

As mentioned above, in the configuration where there are two thermally insulating barriers, the assembly according to the invention is intended to apply in particular to the second thermally insulating barrier, and in the case of a single thermally insulating barrier the invention is intended to apply thereto. Of course it is.

These tanks are, for example, the International Maritime Organization (IMO), such as type NO 96 ^® , type NO 96L03 ^® , type NO 96L03+ ^® or NO 96 MAX ^® , or NO type tanks including MARK III ^® , MARK III ^® Flex+ or FLEX. They are typically named as integral tanks according to the International Maritime Organization (IMO) code.

Preferably, the membrane type or type A, B or C tank contains liquefied natural gas (LNG) or liquefied gas (LG).

The present invention also relates to a transport system for transporting cold liquid products, the system comprising insulated pipelines arranged to connect a vessel as defined above, a tank installed in the hull of the vessel, to a floating or offshore storage unit. , and a pump for pumping the flow of cold liquid product through the insulated pipelines from the floating or offshore storage unit to the ship or from the ship to the floating or offshore storage unit.

The present invention also relates to a method for loading or unloading a vessel as defined above, wherein the cold liquid product is insulated from the floating or offshore storage unit to the vessel or from the vessel to the floating or offshore storage unit. It is passed through pipelines.

The present invention also relates to a method for preparing an assembly of at least two blocks of a polymeric foam, preferably a polyurethane/polyisocyanurate foam, of a thermally insulating slab of a sealed thermally insulating tank as described above, comprising: The following steps are:

a) mixing the chemical components necessary to obtain a foam, preferably a polyurethane/polyisocyanurate foam, said components comprising said foam, optionally at least one reaction catalyst, optionally comprises reagents for obtaining at least one emulsifier and at least one blowing agent;

c) forming and expanding the foam, wherein the expansion of the foam is physically constrained by the walls of the double belt laminator for wrapping, preferably forming a tunnel of rectangular or square cross section; foam is thus inflated to obtain one of the foam blocks of the assembly;

It is characterized by providing a,

At least one wall of a double belt laminator is the side of a foam block referred to as "proximate" that is intended to be positioned adjacent to the "proximate" side of another block having a shape or cross section complementary to said foam block. has a profile to form a complementary shape or cross-section on the top, so that when the two adjacent blocks are in operation or their two opposite sides, the upper and lower sides, have a temperature difference of at least 40°C, preferably at least 80°C. If it has, it is characterized in that the minimum width (L) of the closed portion is reduced by at least 15%.

It is noted that the present invention is intended to include the use of a double belt laminator (DBL) in the context of the preparation of an assembly of two polymer foam blocks, but it is assumed that the two polymer foam blocks are obtained by free expansion as far as possible. One might try, even if in this case it is necessary to provide cutting of the foam blocks after they have been prepared/obtained on the freely inflated face(s).

Unlike the embodiment for the preparation according to the present invention using DBL, the preparation of the fiber-reinforced polyurethane/polyisocyanurate foam is such that the expansion of the fiber-reinforced foam is on at least one side or on at least one expansion side. Since it is said to be due to unconstrained "free expansion", the swelling of the fibre-reinforced foam is free on this side or two sides, unlike a mold which defines the finished volume. Free expansion is typically achieved by omitting the (normal) cover, while the sidewalls prevent flooding of the foam at the sides and the foam naturally inflates upwards, typically beyond the upper ends of these sidewalls.

Following the step of free expansion of the fibre-reinforced polyurethane/polyisocyanurate foam, said fibre-reinforced foam usually has to be cut on its upper side.

Preferably, the method according to the invention comprises a step b) between steps a) and c), said step b) comprising the gravitational flow of said mixture of chemical constituents, of said plurality of fiber reinforcement means. by, impregnation, wherein the fiber reinforcement means are arranged in overlapping layers, and in the overlapping layers, the fiber reinforcement means extend essentially in a direction perpendicular to the direction of the gravitational flow. .

The expression “the fiber reinforcement means extends essentially in a direction perpendicular to the direction of the gravitational flow of the mixture of chemical components” means that these fiber reinforcement means are perpendicular to the direction of the flow of said mixture of components. It means that in the form of a layer of low thickness lying during the impregnation step b) in the plane. Thus, as can be seen in Figure 3, a plurality of fiber reinforcement means having a minimum width (L) and arranged in overlapping layers are transmitted in the longitudinal direction (I), while the mixture of chemical components is chemically It is deposited on the fiber reinforcement means from a distributor allowing/accepting gravity-directed flow of the mixture of components. In other words, the mixture of chemical components leaving the distributor under possible pressure is at least under the effect of its own weight above the stacked fibrous layers, so that it can impregnate these fibrous reinforcements from the upper layer towards the lower layer.

The term "cream time" used hereinafter means that starting from the mixing of the chemical components, the latter initiates the polymerization reaction and then the resulting mixture of components expands and crosslinks (= fiber-reinforced). It means the time required to start step c) of PUR/PIR foam formation). This cream time is well known to those skilled in the art. In other words, cream time is the time elapsed after mixing of the chemical components at room temperature until the mixture turns white under the action of foam expansion and nucleation of bubbles (cells that store gas). Cream time can be determined visually or using an ultrasonic sensor that detects fluctuations in thickness that reflect the formation of foam.

Advantageously, the fiber reinforcing means have variable fiber densities and have a reinforced concentration or density in the area where said interlocking means is located, so that the fiber density in this area is the average fiber density in the finished foam block (T _f ), and preferably between 1.4 T _f and 2 T _f .

Additionally or alternatively, although not shown in the accompanying drawings, at least a portion of the contiguous faces of the foam blocks, preferably at least a portion of the faces of complementary shapes or cross-sections, have a skin, in other words in particular In another material which is resistant to mechanical stresses, such as increased resistance to shear stresses, or which has properties of grip and resistance to friction when two identical surfaces are brought into contact with each other, on its outer surface a mechanical It has coatings or layers that are adhered or bonded together. It is conceivable that this coating or this layer extends from one of the adjacent faces of the block towards the other adjacent face. In this case, this coating or this layer is continuous and at least partially covers the lower side of the block 20 or 21 . This coating or this layer may consist of a composite material having a thickness between 2 millimeters (mm) and 6 millimeters (mm), for example consisting of glass fiber-reinforced plastic.

So, when two adjacent thermally insulating slabs move away from each other or separate due to the cooling of the tank, and consequently the contraction of each of the polymer foam blocks, the complementary shape or cross-section of each of the adjacent blocks is its counter-shape, which together form an interlocking means that opposes this separation, in which case the initial width L (in the steady state) is small or small relative to the phenomenon of shrinkage of the polymer blocks when is cooled. or will be in contact with the counter-section, the resistance to this separation is even more reliable and certain from the point of view of the structure of the polymer foam blocks, and the mechanical strength properties of this shape or section (particularly shear strength and The higher the tensile strength), the better.

With compositions according to the present invention, the use of chemical blowing agents may be combined with the use of physical blowing agents. In this case, the physical expanding agent is preferably mixed in liquid or supercritical form with the foamable (co)polymer composition and then converted to a gaseous state during the PUR/PIR foam expansion step.

Chemical and physical blowing agents are well known to those skilled in the art, and the skilled person will select one or the other in appropriate quantities depending on the PUR/PIR foam they wish to obtain.

Polyols refer to any carbon structure having at least two OH groups.

Since whether what is obtained is a PUR foam, a PIR foam or a PUR-PIR foam depends on the isocyanate/polyol ratio, a PUR foam, PIR foam or PUR-PIR foam will be obtained according to this ratio. If the ratio between the polyol component and the isocyanate component is:

- between 1:1 and 1:1.3, a PUR polyurethane foam will be obtained,

- between 1:1.3 and 1:1.8, a PUR-PIR polyurethane foam will be obtained,

- between 1:1.8 and 1:2.8, PIR polyurethane foam will be obtained.

Polyisocyanates suitable for forming PUR, PIR and PUR-PIR foams are known to those skilled in the art, such as aromatic, aliphatic, cycloaliphatic, arylaliphatic, polyisocyanates and mixtures thereof. , advantageously aromatic polyisocyanates.

Examples of polyisocyanates suitable within the scope of this invention are the 4,4'-, 2,4'- and 2,2'-isomers of diphenylmethane diisocyanate (MDI), any compound resulting from the polymerization of these isomers. , aromatic isocyanates such as toluene-2,4- and -2,6-diisocyanate (TDI), m- and p-phenylene diisocyanate, naphthalene-1,5-diisocyanate; aliphatic; cycloaliphatic; 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (H12MDI), 1,4-cyclohexane diisocyanate (CHDI), bis(iso arylaliphatic isocyanates such as cyanatomethyl)cyclo-hexane (H6XDI,DDI) and tetramethylsilylene diisocyanate (TMXDI). It is also possible to use mixtures of any of these diisocyanates. Advantageously, the polyisocyanates are the 4,4'-, 2,4'- and 2,2'-isomers of diphenylmethane diisocyanate (MDI).

In general, during the formation of PUR foams, PIR foams or PUR-PIR foams, tertiary amines such as N,N-dimethylcyclohexylamine or N,N-dimethylbenzylamine, or bismuth, potassium or tin based It is a known practice to add a reaction catalyst, which may be selected from organometallic compounds, to a mixture comprising a polyol, a polyisocyanate and a blowing agent.

According to a preferred embodiment of the present invention, advantageously, 85% to 99% of the expansion volume of the same fiber-reinforced polyurethane/polyisocyanurate foam when the expansion is left to occur freely without constraint of the walls of this double belt laminator. , the constraint on the expansion of the fiber-reinforced polyurethane/polyisocyanurate foam at the outlet of the double belt laminator, preferably representing 90% to 99%, is dependent on the volume of the fiber-reinforced polyurethane/polyisocyanurate foam. To be followed, the position of the walls of the tunnel of the double belt laminator (DBL) is defined. In this case, the foam is preferably obtained having cells of oval shape oriented along the axis E, which in combination with the properties already described in a plane normal to this axis E (measured according to the ISO 844 standard) leads to advantageous properties of resistance to crushing along this direction (E). Tests and experiments have been conducted by the applicant to determine the preferred broad ranges, mentioned above but not presented here for the sake of clarity and conciseness.

Thanks to the above-mentioned specific parameterization of the constraints on the expansion of the fiber-reinforced PUR/PIR foam in the DBL, a block of fiber-reinforced PUR/PIR foam is obtained, in which at least one of the cells storing a gas of low thermal conductivity is obtained. While 60%, more than 80% overall or even more than 90% extends in the longitudinal direction along an axis parallel to the axis of the thickness E of the foam block, it also has a relationship between the viscosity of the mixture of chemical components and the fiber reinforcement means. In addition to specific selections related to the characteristics, they contribute to the perfect homogeneity of the fibre-reinforced foam blocks. These two properties (the homogeneity of the fiber content T _f in the block and the orientation of the cells outside the region or regions constituting the interlocking means) are good mechanical properties (compressive strength) and It makes it possible to obtain fiber-reinforced foam blocks with excellent mechanical properties (relatively low modulus with respect to tensile strength and thermal shrinkage) in the plane normal to the direction.

As specified above, an elongated or elongated shape can be defined as a shape with elongated length, ie it has one dimension, its length, greater than the other dimensions (width and thickness).

According to one possibility proposed by the present invention, which is not shown in the accompanying drawings, immediately after the step of impregnation of the fiber reinforcement means, it is intended to apply pressure to the upper surface of the assembly consisting of said mixture and fibers. A pressure application system (eg, which may be a system with rolls referred to as "nip rolls") applies a mixture of components and minimal blowing agent to impregnate the fibers. This pressure system, on the one hand, makes it possible to flatten the top surface of the assembly and helps to promote the impregnation of the fibers into the mixture by means of the pressure applied on the assembly. This pressure system may consist of single or double rolls, the relative positions of which are adjusted in such a way that the liquid assembly is forced evenly and perfectly straightened, where applicable above the liquid assembly and below the foam support. In this way, an equal quantity of liquid assembly is obtained at any point in the cross section defined by the space between the conveyor belt and the two rolls or the upper roll. In other words, the main purpose of this pressure system is to supplement the liquid dispensing device, in that it helps to make the liquid assembly uniform in thickness/width before most of its expansion.

Preferably, the kinematic viscosity (η) of said mixture of components is between 30 mPa.s and 3000 mPa.s (or between 0.03 Pa.s and 3 Pa.s), preferably between 50 mPa.s and 1500 mPa.s. s (or between 0.05 　Pa.s and 1.5 Pa.s).

The dynamic viscosity of the mixture of components can be determined using a viscometer or rheometer, eg of the Brookfield type, eg according to the ISO 2555 standard.

In general, since the subject matter of the present invention uses materials/products available or accessible on the market, its properties, particularly those relating to their densities or (dynamic) viscosities, are relevant to the materials/products in question. You may find it useful in certain cases.

Preferably, the fibers (fiber reinforcement means) are arranged over the entire width (B) of the conveyor belt, and the foaming agent and the mixture of components and Step b) of the impregnation of the fibers of is carried out using a controlled liquid distributor simultaneously over the entire width (B).

The term "simultaneously" means that the liquid mixture (reactants and minimal blowing agent) reaches the fibers along a cross section of width L at the same time, so that the impregnation of the various fiber reinforcing means will affect the thickness of the foam block. (or height) and across the same cross-section of the width at the same time or at the same rate.

Advantageously, the blowing agent consists of a physical and/or chemical expanding agent, preferably a combination of the two types.

Preferably, the physical expanding agent is selected from the group consisting of alkanes, cycloalkanes having at least 4 carbon atoms, dialkyl ethers, esters, ketones, acetals, fluoroalkanes, fluoro-olefins having 1 to 8 carbon atoms, and alkyls. tetraalkylsilanes having from 1 to 3 carbon atoms in the chain, in particular tetramethylsilane or mixtures thereof.

In this case, as examples of the compounds, they are propane, n-butane, isobutane, cyclobutane, n-butane, isopentane, cyclopentane, cyclohexane, dimethyl ether, methyl ethyl ether, methyl butyl ether, methyl formate, acetone and fluoroalkanes. The fluoroalkanes selected are those that do not damage the ozone layer, such as trifluoropropane, 1,1,1,2-tetrafluoroethane, difluoroethane and heptafluoropropane. Examples of fluoro-olefins are 1-chloro-3,3,3-trifluoropropene, 1,1,1,4,4,4-hexafluorobutene (e.g. HFO FEA1100 marketed by DuPont) includes

According to a preferred embodiment of the present invention, the selected physical expanding agent is 1,1,1,3,3-pentafluoropropane, or HFC-245fa (available from Honeywell), 1,1,1,3 ,3-pentafluorobutane, or 365mfc (e.g., Solkane® 365mfc sold by Solvay), 2,3,3,3-tetrafluoroprop-1-ene, 1,1,1,2, 3,3,3-heptafluoropropane (also known globally as HFC-227ea marketed by e.g. DuPont), 1,1,1,4,4,4-hexafluorobutene (e.g. by DuPont) commercially available HFO FEA1100), trans-1-chloro-3,3,3-trifluoropropene (Solstice LBA - Honeywell Co.) or mixtures thereof.

Advantageously, the chemical swelling agent consists of water.

Advantageously, during step a) of mixing the chemical components, the nucleation gas is coalesced into the at least one polyol compound using a static/dynamic mixer, preferably under a pressure between 20 and 250 bar, the nucleation gas being It is expressed as being between 0% and 50% by volume of the polyol, and preferably between 0.005% and 20% by volume of the volume of the polyol.

Preferably, during step a) of mixing the chemical components, the temperature of each of the reactants to obtain the polyurethane/polyisocyanurate is between 10°C and 40°C, preferably between 15°C and 30°C. have.

Preferably, according to preferred embodiments of the present invention, the final mixing of the polyol flow, isocyanate flow and/or blowing agent flow is performed at low pressure (<20 bar) or high pressure (>50 bar) using a dynamic or static mixer. takes place inside the mixing head.

According to one possibility proposed by the present invention, an organophosphorus flame retardant, advantageously triethyl phosphate (TEP), tris(2-chloroisopropyl) phosphate (TCPP), tris(1,3-dichloroisopropyl) phosphate ( TDCP), tris(2-chloroethyl) phosphate or tris(2,3-dibromopropyl) phosphate or mixtures thereof, or inorganic flame retardants, advantageously red phosphorus, expandable graphite, aluminum oxide hydrate, trioxide Antimony, arsenic oxide, ammonium polyphosphate, calcium sulfate or cyanuric acid derivatives and mixtures thereof are also added to the mixture in step a).

It is conceivable to use diethyl ethane phosphonate (DEEP), triethyl phosphate (TEP), dimethyl propyl phosphonate (DMPP) or cresyl diphenyl phosphate (CDP) as flame retardants.

This flame retardant, if present in the composition, is in an amount between 0.01% and 25% by weight of the PUR/PIR foam.

The following description is intended to be illustrative only and not limiting with respect to the accompanying drawings.
Figure 1 shows thermal insulation panels forming a barrier or a first thermal insulation layer mounted on a thermal insulation panel forming a second thermal insulation layer of a thermal insulation slab of a hermetically sealed thermal insulation tank according to the prior art. .
Figure 2 is a cross-sectional view showing a portion of another thermally insulating slab of a sealed thermally insulating tank according to the prior art.
Figure 3 is a schematic diagram showing various steps in a method for preparing a fibre-reinforced PUR/PIR foam block of an assembly according to the present invention.
Figure 4 is a schematic view of one embodiment of a foam block with its complementary shape or cross section intended to form an engaging means with another foam block.
5 is a schematic view of one embodiment of an assembly of two polymer foam blocks according to the present invention.
6 is a schematic cross-sectional view showing an embodiment of an engagement means of an assembly of two polymer foam blocks according to the invention.
7 is another schematic cross-sectional view showing an embodiment of an engagement means of an assembly of two polymer foam blocks according to the invention.
Fig. 8 is a schematic cut-away view of a tank of a liquefied gas carrier in which two thermally insulated panel assemblies of the type shown in Figs. 4 to 7 are installed, and a terminal for loading/unloading the tank;

1 and 2 are intended to show the use of polymer foam blocks in the thermally insulating slab of a hermetically sealed thermally insulating tank according to the prior art. In these two figures, the polymer foam blocks do not have substantially the same shape and are in fact intended to be integrated into the thermally insulating slabs of different types of sealed thermally insulating tanks.

However, although the present invention relates to an assembly of two polymer foam blocks having certain characteristics compared to the prior art, in particular by removing all or some of the studs 1 used to attach the foam blocks, the polymer foam as far as possible. It is noted that it is not intended to modify other technical aspects of the thermally insulating slabs of hermetic thermally insulating tanks, except to adapt the latter to the new characteristics of the assemblies of blocks.

1 shows 16 polymer foam blocks 2 forming the primary thermal insulation layer 3 , while a single foam block 4 forms the secondary thermal insulation layer 5 . The wooden panels (6) made of plywood are anchored to the primary sealing membrane (8) shown only in FIG. 2 in the form of a corrugated MARK III® type sealing membrane fixed to some of the wooden panels by means of adhesive bonding. It is attached to the polymer foam blocks (2) forming the strip (7) for anchoring and the primary thermal insulation layer (3).

Underneath the thermal insulation blocks 2 forming the primary layer 3 are, by adhesive bonding, a polymer foam block forming the secondary thermal insulation layer 5 in the case of the thermal insulation slab shown in FIG. 1 . A secondary sealing type membrane 9, also referred to as RBS ("Rigid Secondary Barrier"), fixed to (4). Finally, a wooden panel (13) made of plywood is fastened under the secondary layer (5).

2 , studs 1 and mastic 14 are typically used to attach and secure the secondary layer 5 or thermally insulating sleeve and consequently the sealed thermally insulating tank to the surfaces of the container 15. strips are shown. These surfaces of the container 15 are in particular the walls of a ship, as shown in FIG. 8 , or of a stationary storage tank, for example of the GBS ("Gravity Based Structure") type, or of an offshore mobile storage tank. may consist of

On the one hand, although the present invention is not intended to modify typical elements of a sealed thermally insulated tank other than the polymer foam blocks, the present invention may make it possible to eliminate element(s) of such a tank or replace two blocks. It will of course be entailed modification of the above element(s) due to this function of closing the separating channels or of interlocking or retaining between adjacent polymer foam blocks.

Referring to Figure 3, the preparation of the fiber-reinforced PUR/PIR is preferably carried out in the presence of a catalyst which makes it possible to promote the isocyanate-polyol reaction. Such compounds are described, for example, in the prior art literature entitled "Handbook of Composites (Kunststoffhandbuch), Volume 7, Polyurethanes", Chapter 3.4.1, Third Edition, 1993, published by Carl Hanser. These compounds include amine-based catalysts and catalysts based on organic compounds.

Preferably, the preparation of the fibre-reinforced PUR/PIR foam block according to the present invention is carried out in the presence of one or more stabilizers intended to facilitate the formation of regular cellular structures during formation of the foam. These compounds are well known to the person skilled in the art and, as examples, mention may be made of foam stabilizers with silicones such as siloxane-oxyalkylene copolymers and other organopolysiloxanes.

A person skilled in the art will know the quantities of stabilizers to be used depending on the reactants envisaged, ranging between 0.5% and 4% by weight of the PUR/PIR foam.

According to one possibility proposed by the present invention, during step a) of the preparation method, the mixture of chemical components may contain a polybasic acid, preferably a dibasic acid, an ester acid, a carboxylic acid, with a plasticizer, for example monohydric alcohols. or may consist of polymeric plasticizers such as polyesters of adipic acid, sebacic acid and/or phthalic acid. A person skilled in the art will know the amount of plasticizers contemplated, depending on the reactants used, typically ranging from 0.05% to 7.5% by weight of the polyurethane/polyisocyanurate foam.

Organic and/or inorganic fillers, in particular reinforcing fillers, may be considered in mixtures of chemical constituents such as siliceous minerals, metal oxides (eg kaolin oxide, titanium oxide or iron oxide) and/or metal salts. The quantity of these fillers, if present in the blend, is typically between 0.5% and 15% by weight of the PUR/PIR foam.

It should be noted that the present invention is not intended here to add technical teachings to the formation of PUR/PIR foam, both in terms of the nature of the essential chemical constituents and the optional functional agents and their individual quantities. You just have to pay attention. A person skilled in the art will know how to obtain different types of fibre-reinforced PUR/PIR foams, and the present preparation is a specific choice of characteristics of fiber reinforcement means, in particular fibers in different fiber reinforcement means. densities of them, more particularly those intended to be in the complementary shape or cross-section of each foam block, and equally specific selection of foam for impregnation of said reinforcing means.

As can be seen in FIG. 3, a plurality of fiber reinforcement means 10 are unwound and then on a conveyor belt 11 intended to transport these reinforcement means 10 and the components forming the PUR/PIR foam. Or, on it, they become aligned parallel to each other. Specifically, the impregnation of the fiber reinforcement means 10 is carried out by gravity within the framework of the preferred mode of preparation of the fiber-reinforced foam block of the present invention, that is to say the chemical components, the foaming agent(s) and the PUR/ A mixture (12) of any other functional agents used to obtain the PIR foam is poured directly onto the fibers (10) from a liquid distributor located above the fiber reinforcement means (10).

Thus, the above mixture 12 must impregnate all the layers of the fiber reinforcement means 10 in a very homogeneous manner during the cream time t _c , whether the latter is several mats or several fabrics, so that the fiber Expansion of the PUR/PIR foam starts after the reinforcing means 10 have been suitably all impregnated with the mixture 12 or at the earliest. In this way, expansion of the PUR/PIR foam is achieved while maintaining a perfect specific distribution of fibers 10 in the volume of the PUR/PIR foam block to obtain the desired fiber density gradient.

In the context of the present invention, the cream time of the components of the mixture 12 for forming the PUR/PIR foam is known to those skilled in the art and, when the expansion of the foam has just begun, the conveyor belt 11 In this way, the expansion of the PUR/PIR foam is thus double It is selected in this way that it ends up in the belt laminator.

In this embodiment with a double belt laminator (DBL), a pressure system using one or more rolls is optionally arranged before the double belt laminator, i.e. between the double belt laminator and the zone of impregnation of the mixture on the fibers have. In the case of the use of DBL, the expansion of the volume of a foam if the expansion volume of this foam reaches between 30% and 60% of the expansion volume of the same foam when left to expand freely, i.e. without any constraints. takes place inside the laminator. In this way, if the foam is close or relatively close to its maximum expansion, i.e. its expansion brings the foam close to all of the walls of the double belt laminator, forming a tunnel of rectangular or square cross section, The double belt laminator will be able to constrain the expansion of the PUR/PIR foam to its second state of expansion. According to a different way of presenting the specific choices involved in the preparation, the gel point of the mixture of constituents, i.e. the moment at least 60% of the polymerization of the mixture of constituents is reached, in other words the maximum volume expansion of the mixture. 70% to 80% of the , essentially occurs within the double belt laminator at the second half of the length of the double belt laminator as possible (ie closer to the outlet of the laminator than to the inlet of the latter).

Regarding the function of simultaneous distribution of the mixture 12 of the blowing agent and chemical components over the entire width B (corresponding to the width of the conveyor belt 11) of the fiber reinforcement means 10, this is shown in the accompanying drawings. This can be ensured by an invisible controlled liquid distributor. This dispenser has a channel for taking the assembly formed from a mixture of the minimum blowing agent and chemical components from a reservoir forming a reactant mixer, in which, on the one hand, all the chemical components and the blowing agent are mixed, and the other On the one hand, in particular, nucleation or even heating of this mixture takes place. This liquid assembly, formed of a mixture 12 of blowing agent and chemical components, then having a plurality of nozzles for the flow of said mixture 12 over the fiber reinforcement means 10 (substantially L/ It is distributed under pressure in two transversely extending channels each ending in two identical distribution plates 18 extending across the width B) each having a length equal to 2. These flow nozzles may consist of calibrated cross-section orifices having a given length. Since the length of these flow nozzles is thus determined, it is determined that the liquid comes out at the same flow rate across all the nozzles, so that the impregnation of the fiber reinforcement means 10 occurs at the same time or simultaneously at the width B of the fiber reinforcement means 10. across the cross-section, and therefore the surface density of the liquid deposited in a straight line with each nozzle is the same. In this way, taking a cross section of the width B of the fibers 10, the impregnation of the layers of the fibers 10 by the mixture 12 occurs at all points on this cross section, since the later ones are impregnated simultaneously. Performed in the same way, it helps to obtain a block of fiber-reinforced foam at the output of the double-belt laminator, in which the local fiber density is the same as that of the fiber at the time of gravitational pouring of the mixture 12. It corresponds exactly to the fiber density of each of the overlapping layers of reinforcing means.

One important aspect for achieving good impregnation of the fiber reinforcement means 10 immediately before the cream time (t _c ) of the PUR/PIR foam is related to the specific characteristics of the various fiber reinforcement means, which depend on the fiber density (foaming agent It lies in the selection of a specific viscosity of the liquid (consisting of a mixture 12 of chemical constituents). The viscosity range chosen together with the permeability characteristics of the fiber reinforcements is such that the fibers (i.e. the lower layer of fibers 10 located at the bottom in the stack of fiber reinforcements) reach the sequential layers immediately above the last layer. Since it must allow good penetration of the liquid into the first layers of the fibers 10), the impregnation time ti of the fibers 10 has a chemical value corresponding substantially to, but not always less than, the cream time t _c Achieved within a period determined by the components. The viscosity of the mixture of components 12 is selected, for example, through heating, addition of plasticizers and/or rather substantial nucleation, so that the fibers 10 by the mixture 12 of blowing agents and chemicals over a cross-section of width B ) are obtained just before the cream time, that is, before or just before the start of expansion of the PUR/PIR foam.

Fiber-reinforced foam blocks are intended for use in very specific environments and must therefore ensure specific mechanical and thermal properties. The fiber-reinforced foam block obtained by the preparation described above is thus the upper or primary panel and/or lower part of this insulating slab of a tank 71 intended to contain extremely cold liquids such as LNG or LPG. or in the secondary panel, typically part of a thermally insulating slab in the examples used in FIGS. 4 and 5 . Such a tank 71 may be, for example, a storage tank on land, a floating barge or the like (“Floating Storage Regasification Unit” (FSRU) or “Floating Liquefied Natural Gas”). "Liquefied Natural Gas") or even ships such as liquefied gas carriers that transport this liquid fuel between two ports.

4 shows one embodiment of a polymer foam block 20 forming an assembly according to the invention with another polymer foam block 21 . As can be seen, the foam block 20 has an L-shaped tab or protrusion 245, 25 on these two lateral faces 22, 23, and each lateral face of the block 20 The L-shaped tabs or protrusions 24, 25 on 22, 23, as can be seen in FIG. 6 or 7, these tabs or protrusions 24, 25 are close to the foam block 21 It is inverted or opposite, to allow it to fit together with the tabs or protrusions 24, 25 on the top.

To prevent any detrimental thermal phenomena, the vertical portion(s) 26, 27, i.e. the portions passing through the thickness of the foam block or blocks 20, 21, are covered with intumescent thermal insulating material 28 such as glass wool. It may be provided at least partially filled. These elements 28, 31 can be secured by adhesive bonding, stapling, or simply positioned using a third element to hold them in place by pressure.

that the duct or channel 30 does not extend over the entire height or thickness, and that the vertical portions 36 and 37 of the duct or channel 30 are of the foam block in the embodiment shown in FIGS. 5 and 6 . It is also important to note that it extends over only 2/3 of its height or thickness. Thus, the complementary shape or cross section 24, 25 of the adjacent foam blocks 20, 21, on the one hand, when the tank 71 is in working condition, i.e. the cold liquid load is at least 20 of its maximum storage volume. In the state of expressing %, it makes it possible to ensure the function of interlocking, containment or retention between blocks, on the other hand it makes it possible to avoid any undesirable thermal phenomena such as thermocyphering .

The closed portion(s) 60 of the duct or channel 30 that are most likely to come into contact when the adjacent polymer foam blocks contract, advantageously caused by the adjacent foam blocks 20, 21 moving closer together. It may be provided with a flexible material 31 having high plasticity to absorb the mechanical stresses associated with the tensions being applied. Those parts of the channel 30 or of the duct that are most likely to move away from each other when the adjacent polymer foam blocks 20, 21 are contracted advantageously have an intumescent insulating material 28 as mentioned above, or even It has the same flexible material 31 as described above that can deform elastically and/or plastically while maintaining a mechanical connection forming a closed wall as far as possible between the two blocks 20 , 21 .

In the embodiment shown in FIG. 6 , the closed parts or parts 60 of the channels or ducts 30 consist of inclined planes, the length of which represents at least one third of the height or thickness of the blocks 20 or 21 . are doing Since the length of this closure section 60 is substantial, it can be used and tends toward mechanically connecting two adjacent blocks 20, 21 and bending or tightening the blocks 20, 21. This is the case if the faces are brought into contact when the blocks 20, 21 contract as an engagement means enabling to absorb the forces present.

7 shows an alternative embodiment of the engagement means according to the invention. In this example, the closure 60 or engagement means (if applicable) does not have a point of symmetry for the two blocks 20, 21 unlike the embodiment of FIGS. 4 to 7 . Specifically, in this embodiment, the closure portion 60 emerges from a hooking tongue 33, which is a thin first proximal portion 34 whose thickness or height is reduced. extends from the lateral face 23 of the block 21 at , and is at least twice as long as the proximal portion 34 and wider at least twice the thickness or height of the proximal portion 34 . It widens in the second section towards the end portion 35 . The closure part 60 has a shape or cross section complementary to this hooking tongue 33 consisting of a compact hooking foot 36 on the block 20 adjacent to the other side. This asymmetry between the two complementary shapes or cross-sections 33, 36 has the advantage of allowing the production of a compact shape or cross-section 36 compared to the embodiment of Figs. If the two faces of the slabs 20, 21 are in contact at the closed part 60, for example, if the block 20 or 21 is located somewhere with a tank which makes it more subject to contraction, the other The movement of the side foam block 21 in the away direction can be further resisted.

Referring to Fig. 8, a cutaway view of a liquefied gas carrier 70 shows a generally prismatic sealed insulated tank 71 mounted within a double hull 72 of the carrier. The wall of the tank 71 is a primary hermetic barrier intended to be in contact with the LNG contained in the tank, a secondary hermetic barrier arranged between the primary hermetic barrier and the double hull 72 of the carrier. , and two insulating barriers arranged between the primary sealed barrier and the secondary sealed barrier and between the secondary sealed barrier and the double hull 72, respectively.

In a manner known per se, loading/unloading pipelines 73 arranged on the upper deck of the carrier are shore for transporting a cargo of LNG from or to the tank 71 using suitable connectors. Alternatively, it can be connected to a port terminal.

8 shows an example of a coastal terminal with loading and unloading stations 75 , submersible pipes 76 and offshore installations 77 . The loading and unloading station 75 is a stationary offshore installation comprising a movable arm 74 and a tower 78 supporting the movable arm 74 . The movable arm 74 carries a bundle of insulated flexible pipes 79 , which can be connected to loading/unloading pipelines 73 . The orientable moveable arm 74 can be adjusted to fit all sizes of liquefied gas carriers. A connecting pipe (not shown) runs inside the tower 78 . The loading and unloading station 75 allows loading and unloading of the liquefied gas carrier 70 to or from the offshore installation 77 . The installation has tanks 80 for storing liquefied gas and connecting pipes 81 connected by means of submersible pipes 76 to a loading or unloading station 75 . The submersible pipe 76 allows transport of liquefied gas between the loading or unloading station 75 and the offshore installation 77 over long distances, for example 5 km, which is a long distance from the beach during loading and unloading operations. It makes it possible to keep the liquefied gas carrier 70 at a distance.

Pumps aboard the carrier vessel 70 and/or pumps fitted to the offshore facility 77 and/or pumps fitted to the loading and unloading station 75 to generate the pressures necessary to transport the liquefied gas. their use is made.

As stated above, the subject matter of the present invention, i.e. the fibre-reinforced polyurethane/polyisocyanurate foam block in this case, is not intended to be applied only to or used for tanks which are integrated into a supporting structure, and is not intended to be used for such tanks. Not only is it provided for Type A Tanks, B Tanks and C Tanks as defined in the IGC Code in force on the filing date of the application, but there are also very substantial amendments with respect to these Type A Tanks, B Tanks and C Tanks. It is also provided for future versions of this code if not done for .

In the following, some of the experiments and tests performed by the applicant in order to make it possible to evaluate the subject matter and scope of the present invention are presented, many tests/experiments have been performed but if necessary/needed Please note that this may be provided at a later date if necessary.

Figures 6 and 6, where the foam blocks are placed under temperature conditions representative of their operating conditions, with a difference of more than 80 °C between the upper and lower faces (as is the case for a tank containing LNG). Numerous tests have been performed on full-size PUR/PIR foam blocks of the type shown in Fig. 7.

On average, a reduction of more than 15%, in practice more than 50%, of the minimum width L of the channel/duct at the closure site 60 was observed. During use of the tank (= the foam blocks 20, 21 are When in a working situation) the blocks are brought into contact through the closure part 60 which prevents bending/tightening while reinforcing the mechanical stability of the assembly of the blocks.

Furthermore, it should be noted that the assembly of the two PUR/PIR foam blocks according to the invention shows no significant impairment of their properties related to (very low) thermal conductivity.

Thermal conductivity (mW/m.K) at -160℃ at -120℃ at +20℃ 10-14 11-16 23-27

Although the present invention has been described in connection with some particular embodiments, it is not intended to be limited thereto, and all technical equivalents of the means described, as well as combinations thereof, provided that these fall within the scope of the present invention. It is self-evident that they include

Use of the verb "to include" or "comprise" and its conjugations does not exclude the presence of other elements or steps in addition to those recited in a claim.

In the claims, any reference sign placed between parentheses shall not be construed as a limitation on the claim.

Claims (19)

assembly of at least two blocks of polymeric foam (20, 21), preferably polyurethane/polyisocyanurate foam, of a thermally insulating slab of a hermetically sealed thermally insulating tank (71),
The density of the foam blocks (20, 21) having at least lateral faces as well as upper and lower opposite faces is between 30 kg/m ³ and 300 kg/m ³ ,
The first and second foam blocks 20, 21 have faces referred to as "proximate" faces 22, 23,
Since the two blocks 20, 21 are arranged adjacently, the adjacent lateral face 22 of the first foam block 20 and the adjacent lateral face 23 of the second foam block 21 forms between them a channel or duct 30, which, when said blocks 22, 23 are in a stable state, i.e. between their two upper and lower opposite sides, In a state where there is no temperature difference, it has a minimum width (L) over at least one part referred to as the closed part of the channel or the duct,
The adjacent surfaces 22 and 23 of the first and second blocks 20 and 21 have the shape or shape of the other adjacent surface 22 or 23 of the first or second foam block 20 or 21. having at least a shape or cross section substantially complementary to cross section 24 or 25, respectively;
When the two adjacent blocks are in operation, i.e. when the two opposite upper and lower sides have a temperature difference of at least 40 °C, preferably at least 80 °C, the width L of the closed section is at least Assembly, characterized in that reduced by 15%. According to claim 1,
The assembly, characterized in that said width (L) is reduced by at least 50%. According to claim 1 or 2,
Assembly, characterized in that said channel or duct (30) has a non-straight path in the cross-sectional plane (P). According to any one of claims 1 to 3,
Assembly, characterized in that the minimum width (L) in working conditions is equal to zero, so that at least in the closed region the two adjacent blocks are in contact. According to any one of claims 1 to 3,
The closed portion comprises a material (28 or 31) having a compressive capacity equal to at least 15%, preferably at least 50%, and is preferably made of glass wool or rock wool (28) or elastomer (31). Assembly characterized in that consisting of. According to any one of claims 1 to 5,
Assembly, characterized in that said substantially complementary shapes or sections (24, 25) consist of a male part and a female part, respectively. According to any one of claims 1 to 6,
At least one foam block (20 or 21), preferably two foam blocks (20, 21), has a fiber-average fiber density (T _f ) between 1% and 60% by weight of fibers (10). It is made of reinforced foam,
Preferably, the fibers 10 are elongated or continuous, and the fibers 10 are made of glass fiber, basalt fiber, hemp fiber or any other organic or inorganic material, preferably the fiber ( 10) assembly, characterized in that consisting of glass fibers. According to claim 7,
The complementary shapes or cross-sections have a fiber 10 density greater than the average fiber density (T _f ), preferably between 1.2 T _f and 3 T _f , preferably between 1.4 T _f and 3 T f . Assembly characterized by having a fiber (10) density between 2 T _f . The method of any one of claims 1 to 3 or 5 to 8,
The assembly, characterized in that said channel or said duct comprises a thermally insulative material, preferably a glass surface. According to any one of claims 1 to 9,
The assembly, characterized in that the first and second foam blocks (20, 21) have a substantially parallelepiped or cube shape. According to any one of claims 1 to 10,
The assembly, characterized in that the width (L) is between 1 millimeter and 12 millimeters in a steady state, preferably between 1.5 millimeters and 6 millimeters. According to any one of claims 1 to 11,
Preferably the density of the fiber-reinforced foam blocks 20, 21 is between 50 kg/m ³ and 250 kg/m ³ , preferably between 90 kg/m ³ and 210 kg/m ³ Assembly characterized in that. According to any one of claims 1 to 12,
A composite layer or coating wherein at least one portion of one of the adjacent surfaces 22 or 23, preferably both adjacent surfaces 22 and 23, has a Young's modulus greater than the Young's modulus of the complementary shape or cross-section. An assembly comprising a. A sealed thermally insulated tank (71), said tank (71) comprising:
- a hermetically sealed thermally insulating tank comprising at least one hermetically sealed metallic membrane composed of a plurality of metallic strakes or metallic plates which may contain corrugations, and at least one thermally insulating barrier adjacent said membrane; a tank integrated within a supporting structure comprising a thermally insulating slab comprising; or
- Type A, B or C tanks according to the definition given by the IGC Code, containing at least one thermally insulating slab;
consists of,
characterized in that the thermally insulating slab comprises an assembly of at least two foam blocks (20, 21) as claimed in any one of claims 1 to 13. ). As a vessel (70) for transporting cold liquid products,
Said ship includes at least a sealed thermally insulated tank (71) and a hull (72) as claimed in claim 13, said sealed thermally insulated tank (71), wherein said tank (71) is an IGC A vessel (70), characterized in that it is mounted on said vessel (70) or located in said hull, if it is a type A, B or C tank according to the definition given by the code. As a transport system for transporting cold liquid products,
The system as claimed in claims 1 to 15 is arranged to connect a vessel (70), the tank (71) installed in the hull of the vessel, to a floating or offshore storage unit (77) insulated pipelines (73, 76, 79, 81) in and from the floating or offshore storage unit to the vessel 70 or from the vessel 70 to the floating or offshore storage unit. A delivery system comprising a pump for pumping a flow of cold liquid product through As a method for loading or unloading a vessel (70) as claimed in claim 15,
The cold liquid product passes through insulated pipelines (73, 76, 79, 81) from the floating or offshore storage unit (77) to the vessel (71) or from the vessel (71) to the floating or offshore storage unit (77). A method characterized in that delivered through. of a polymeric foam (20, 21), preferably a polyurethane/polyisocyanurate foam, of the thermally insulating slab of the hermetically sealed thermally insulating tank (71) as claimed in any one of claims 1 to 13; A method for preparing an assembly of at least two blocks, said method comprising the following steps:
a) mixing the chemical components necessary to obtain a foam, preferably a polyurethane/polyisocyanurate foam, said components comprising said foam, optionally at least one reaction catalyst, optionally contains reagents for obtaining at least one emulsifier and at least one blowing agent;
c) forming and expanding the foam, wherein the expansion of the foam is physically constrained by walls of an enclosing double belt laminator, preferably forming a tunnel of rectangular or square cross section, wherein the foam is thus inflated to obtain one of the foam blocks of the assembly;
It is characterized in that it contains,
At least one wall of the double belt laminator has a shape or cross-section 24, 25 complementary to that of the foam block 20 or 21, the "proximal" face 22 of another block 20 or 21. or 23) for forming a complementary shape or section 24, 25 on the face of the foam block 20 or 21, referred to as "adjacent" 22, 23, which is intended to be located adjacent to 23). profile, so that the closure is possible when the two adjacent blocks 22, 23 are in operation or when their two opposite upper and lower sides have a temperature difference of at least 40°C, preferably at least 80°C. characterized in that the minimum width (L) of the site is reduced by at least 15%. A method for preparing a foam block as claimed in claim 18, said method comprising a step b) between steps a) and c), said step b) comprising a plurality of fibers (10). ) of reinforcing means, by the gravitational flow of the above mixture of chemical components, consisting of a step of impregnation, wherein the fiber 10 reinforcing means are arranged in overlapping layers, and in the overlapping layers characterized in that the fiber (10) reinforcing means extend essentially in a direction perpendicular to said direction of gravitational flow.

Images