Prismatic liquid hydrogen tank

Abstract

A prismatic tank for containing a liquefied gas. The tank is formed of an extruded material and includes an outer insulating layer.

Description

BACKGROUND

[0001] The present invention relates to a tank for containing and transporting liquefied gas, i.e. a containment system for cryogenic liquids. The invention is particularly, but not exclusively, applicable to the storage and transportation (and in the case of fuel, consumption) of cryogenic liquids such as liquefied hydrogen and liquefied natural gas (LNG) as cargo or as fuel.

[0002] Transporting such liquefied gases allows a large quantity of gas to be transported in one trip, which reduces pollution and increases transportation efficiency. In order to transport such liquefied gases, the vessel must maintain extremely low temperatures during the voyage.

[0003] By insulating the tank for containing the liquefied gas, it is achieved that the gas is maintained in a liquid state at these low temperatures. This is usually in the form of one or more layers of insulating material such as polyurethane foam, which can be sprayed onto the surface of the tank or installed in the form of prefabricated panels, which usually include the use of plywood, which prevents the surrounding heat from reaching the cargo tank (liquid cargo tank) and heating the liquefied gas.

[0004] Such systems have been successfully used in various gas carriers capable of safely transporting liquefied gases worldwide.

[0005] However, the inventors have devised a new device which allows the containment of liquefied gases at extremely low temperatures and which more efficiently insulates the liquefied gases from the surrounding conditions than existing methods. More particularly, the invention described herein allows the insulation of cargo or fuel tanks at temperatures close to absolute zero, i.e. below -250 degrees Celsius.

[0006] Advantageously, such a system allows the containment of gases such as hydrogen or methane and the maintenance of such gases in a liquid state. The combustion of hydrogen into mechanical energy in a combustion process or the conversion of hydrogen into electrical energy in a fuel cell produces only water as waste, so the ability to contain and use this fuel provides significant environmental and efficiency advantages. It also allows ship and fleet operators to comply with more stringent environmental regulations that can apply to the shipping industry in the future.

[0007] The containment system can find that it is used in the land-based sector as well as stationary containment and road and rail-based transportation.

[0008] Other advantages are described herein. SUMMARY

[0009] Aspects of the invention described herein are set out in the appended claims.

[0010] Viewed from a first aspect of the invention described herein, there is provided a prismatic or spherical tank as claimed in the claims.

[0011] The invention relates to the retrofitting of tanks suitable for containing and transporting liquefied gas at low temperatures. The ability to contain such liquefied gas on board for extended periods of time has led the inventors to depart from the current industry standards for the design and construction of ship tanks.

[0012] By way of illustration, the design and construction of cargo containment systems and tank types are governed by the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk ("IGC Code") applicable to all gas carrier ships and the International Code for the Safety of Ships Carrying Gas or Other Dangerous Goods in Bulk ("IGF Code") applicable to ships equipped with gas-fuelled propulsion and auxiliary systems.

[0013] There are special provisions for liquefied gas carrier ships, i.e. cargo containment systems in ships.

[0014] A cargo containment system is a term used to describe the overall arrangement for containing cargo (or fuel, as the case can be) and includes the following:

[0015] 1. The primary barrier (cargo hold),

[0016] 2. The secondary barrier (mandatory for Type A tanks),

[0017] 3. The associated insulation,

[0018] 4. Any intermediate spaces (for maintenance), and

[0019] 5. If necessary, also the adjacent structure for supporting these elements

[0020] For cargo transported at temperatures as low as -55 degrees Celsius, the hull can act as the secondary barrier, in which case it can be the boundary of the cargo hold space within the ship.

[0021] The basic cargo hold types used on gas carriers are in accordance with the following definitions:

[0022] Independent tanks - Types "A", "B" and "C"

[0023] Independent tanks are completely self-supporting and do not form part of the hull structure. In addition, they make no contribution to the strength of the hull. According to the IGC Code, there are three different types of independent tanks on gas carriers, mainly depending on the design pressure. These are referred to as:

[0024] i) Type "A";

[0025] ii) Type "B"; and

[0026] iii) Type "C".

[0027] Type "A" capsule

[0028] Type «A» tanks are mainly composed of flat surfaces. The maximum allowable tank design pressure in the vapor space for this type of system is 0.7 barg. This means that the cargo must be transported under full refrigeration conditions at or close to atmospheric pressure (typically below 0.25 barg). This type of tank is self-supporting and requires conventional internal stiffening (similar to the normal hull structure of the ship itself).

[0029] Type «A» tanks can not be resistant to crack propagation. Therefore, to ensure safety in case of cargo tank leakage, a secondary containment system is required. This secondary containment system is called secondary barrier and is a feature of all ships with Type «A» tanks capable of carrying cargo below -10 degrees Celsius.

[0030] The secondary barrier must be a complete barrier capable of containing the entire tank volume at the specified keel angle. IGC regulations state that the secondary barrier must be capable of containing a tank leak for 15 days.

[0031] Type "B" capsule

[0032] Type «B» tanks can be composed of flat surfaces or can be spherical. This type of containment system is subject to more detailed stress analysis compared to Type «A» systems. These controls must include fatigue life investigation and crack propagation analysis.

[0033] Due to the enhanced design factors, Type «B» tanks only require a partial secondary barrier in the form of a drip tray around and below the tank to collect any escaped liquids.

[0034] There are prismatic Type «B» tanks in LNG service today. Prismatic Type «B» tanks make use of the main deck space of the ship. For Type «A» tanks, the maximum design vapor space pressure limit is 0.7 barg.

[0035] Type "C" capsule

[0036] Type «C» tanks are usually spherical or cylindrical pressure vessels with a design pressure of 2 barg or higher. Cylindrical vessels can be installed vertically or horizontally. This type of containment system is always used for semi- and full-pressure gas carriers.

[0037] Type «C» tanks are designed and built according to the relevant pressure vessel codes and are subject to detailed stress analysis. In addition, the design stresses remain low. Therefore, Type «C» tanks do not require a secondary barrier.

[0038] Type "C" tanks can be designed for a maximum working pressure of about 18 barg. For semi-pressurized vessels, the cargo tank and associated equipment are designed for a working pressure of about 5 to 7 barg, with a vacuum of 0.5 barg. It is stated that the tank steel of semi-pressurized vessels is capable of withstanding transport temperatures as low as -104 degrees Celsius (for ethylene, and also including -48 degrees Celsius for liquefied petroleum gas (LPG)).

[0039] Membrane capsule

[0040] The concept of a membrane containment system is based on a very thin primary barrier (membrane - 0.7 to 1.5 mm thick) supported by a thermal insulation material. This tank is not self-supporting like an independent tank. The inner shell forms the load-bearing structure. A membrane containment system must always be provided with a secondary barrier to ensure the integrity of the entire system in the event of a leak in the primary barrier.

[0041] According to the invention described herein, an improved Type B tank is provided. In particular, the invention described herein provides a prismatic tank which can accommodate an internal pressure of 2 barg or more by alternative design.

[0042] In particular, looking at the first aspect of the invention described herein, there is provided a prismatic tank for containing liquefied gas, the tank comprising a plurality of substantially planar side walls defining two opposite ends, two opposite sides and an upper surface opposite a lower surface, the planar side walls defining a volume for containing liquefied gas, the prismatic tank further comprising edge portions at the intersections of the planar side walls, wherein the edge portions and the planar side walls can be extruded pieces.

[0043] Thus, a tank structure can be provided which is formed from a plurality of extruded components. Using extruded pieces can allow for the formation of components of the same kind, thereby allowing for optimized use of material and strength. This also minimizes joints and couplings which can disrupt the continuity of the structural strength.

[0044] Advantageously, this structure allows for the provision of a hybrid tank structure which combines the attributes of a Type B tank (as described above) with the ability to accommodate internal pressure. A new type of tank design is described herein.

[0045] In practice, the tank construction defines a pressure vessel for containing cryogenic liquefied gas.

[0046] As described above, Type A and Type B tanks are non-pressurized (they can withstand a pressure of up to 0.7 barg), and do not need to take into account the EU pressure directive or any other requirements / regulations relating to pressure vessels. Type C tanks can withstand higher pressures (above 0.7 barg), and are by definition pressure vessels.

[0047] The pod structure described herein is not any of the above, but is a new type of pod based on a prismatic design and capable of withstanding pressures above 2 barg. As such, it is a pressure vessel and needs to comply with such requirements.

[0048] The extruded structure of the prismatic pod allows for engineering, i.e. designing to accommodate a predetermined internal pressure. For example, by selecting the cross section of the components forming the pod to provide the required strength in terms of stress, strain and safety margin, it is possible to contain an internal pressure of 2 barg or more within such a pod. Reinforcements within the pod itself can also be included and incorporated as a measure to prevent sloshing / shaking, allowing the pod to also be filled at any level of height.

[0049] Advantageously, the construction described herein allows for a prismatic pod that does not require a secondary barrier; this becomes an optional addition.

[0050] The sub-components forming the pod can be of different materials, for example the walls and edge portions can be of different materials to accommodate predetermined loads. However, advantageously, the materials can be the same, i.e. a common material. This advantageously allows for continuity of thermal expansion, more reliable welding or joining and additionally further enhances the use of techniques such as friction stir welding (FSW) to increase the strength of the weld.

[0051] Any suitable material can be used. However advantageously, aluminium or an alloy thereof can be used to optimise strength whilst minimising the weight of the pod.

[0052] The flat side walls of the pod can be formed from a single or multiple extrusions welded together. Advantageously, forming the flat sections of the pod from multiple sections welded together allows for many manufacturing and technical advantages, including but not limited to:

[0053] - the use of smaller extrusion machines to form the prismatic pod. This increases the flexibility of the pod manufacturing location;

[0054] - lower manufacturing costs; and

[0055] - the ability to build larger pods according to the method described herein. For example, when used as a fuel pod application, very large fuel pods can be built to fit into a hull to contain fuel.

[0056] The edge sections can have a cross-sectional shape having a first edge for joining to a first side wall and a second edge for joining to an adjacent side wall, the first edge and the second edge being arranged at 90 degrees to each other, and wherein the first edge and the second edge define a weld line along which the side walls can be welded.

[0057] Thus, corner sections can be provided which can also be conveniently extruded. The 90 degrees of each corner section or edge section provides a box or rectangular shaped pod. It will be appreciated that other angles can be used to allow the pod to fit into different applications. For the ISO containers discussed herein, the 90 degree angle conveniently allows the pod to follow the internal space defined by the container frame dimensions.

[0058] The edge also provides a convenient straight line along which a weld can be formed. Due to the pressurised nature of the pods described herein, the inventors have determined that ensuring the welds are each displaced from the intersection of the first side wall and the adjacent side wall advantageously allows the edge and corner to be optimised from the extruded section without including the welds. Such welds are detrimental to the joint strength between the adjacent panels at the point of high stress. Any suitable displacement can be used, such as for example at least 10 centimetres, which advantageously controls the load within the edge and corner portions.

[0059] The edge portion in cross-section can be in the form of two perpendicular portions for connection to the associated flat side walls, and an intermediate portion connecting the two perpendicular portions, wherein the intermediate portion is arranged at a 45 degree angle to each of the two perpendicular portions. Thus, a truncated corner is provided which can also be extruded. This also advantageously optimises the strength of the edge or corner.

[0060] Further strength can additionally be provided by forming a radius at the point where the intermediate portion meets the perpendicular portions.

[0061] As mentioned above, different welding techniques can be used. Advantageously, a friction stir weld (FSW) can be used to form the welded joint, i.e. the edge portion and flat side walls are joined together by FSW. This provides an extremely strong weld without melting the material.

[0062] The pod can also be provided with an insulation layer around the pod and allowing the containment of cryogenic liquid within the pod. Aspects of the insulation will now be described.

[0063] In one arrangement, the pod can also comprise an outer insulation layer arranged on the outer surface of the substantially flat surface and on the outer surface of the edge section.

[0064] The insulation material can be in the form of an insulating foam.

[0065] The insulation layer can be in the form of one or more coaxial sleeves defining a space around the prismatic pod to receive the insulating material. In another arrangement, the insulation layer can be in the form of a plurality of tessellating insulating panels. Thus, a prismatic pod of any shape can be fully insulated.

[0066] For example, the thermal insulation layer can be in the form of a modular thermal insulation device comprising one or more tessellated thermal insulation units, each unit comprising a first, inwardly facing layer and a second, outwardly facing layer spaced apart from the first layer, the two layers defining a space therebetween, and one or more spacing members extending between the first and second layers, and wherein the surfaces defining the first layer, the second layer and an outer perimeter extending around the device are gas impermeable surfaces.

[0067] Further, the space between the first and second layers and the surfaces defining the outer perimeter of the device define an internal volume of the device, and wherein the spacing members are arranged, in use, to resist atmospheric pressure acting on the surfaces when the internal volume is evacuated of air.

[0068] Thus, a vacuum thermal insulation device can be provided in conjunction with a novel tank configuration. This will allow cryogenic liquids, such as cargo or fuel, to be contained in such a prismatic tank.

[0069] Further, to facilitate transportation, loading and unloading of the prismatic tanks described herein, the tank can advantageously be contained within an ISO container frame conforming to ISO dimensional regulations described herein.

[0070] Still further, the tank device can comprise a perimeter frame that allows selective coupling to similar frames, such that a plurality of prismatic tanks can be coupled together in a stack or matrix.

[0071] To allow for convenient loading and unloading of the tank, an inlet and an outlet port can be provided to allow cargo and / or fuel to be loaded into and removed from the tank. Advantageously, adjacent tanks can be provided with pre-configured piping to allow simultaneous loading and unloading of the tanks. This can be particularly useful for convenient liquid transfer or in fuel applications where a continuous fuel flow is required.

[0072] A plurality of tanks as described above can then be conveniently arranged in a matrix on board or inside a ship.

[0073] Viewed from another aspect of the application described herein, there is provided a fuel tank for a ship, wherein the tank has a prismatic structure for containing a liquefied gas, the tank comprising a plurality of substantially planar side walls defining two opposite ends, two opposite sides and an upper surface opposite a lower surface, the planar side walls defining a volume for containing the liquefied gas, the prismatic tank further comprising edge portions at intersections of the planar side walls, wherein the edge portions and the planar side walls are extrusions.

[0074] Viewed from yet another aspect, there is provided a ship containing prismatic tanks as described herein. BRIEF DESCRIPTION OF DRAWINGS

[0075] Aspects of the application will now be described, by way of example only, with reference to the accompanying drawings in which:

[0076] Figure 1 A cross-sectional view of a vessel that may incorporate the invention described herein is shown;

[0077] Figure 2 The sub-components of the prismatic compartment described herein are shown;

[0078] Figure 3 A, 3B, and 3C show the edge profiles of the cabin described herein;

[0079] Figure 4 Alternate views of the sub-components of the cabin described herein are shown;

[0080] Figure 5 A, 5B, and 5C show cross-sectional views of the prismatic cabin, insulation layer, and internal reinforcement.

[0081] Figure 6 A, 6B and 6C show cross-sectional views of a compartment with alternative reinforcement devices;

[0082] Figure 7 A and 7B show Figure 6 The reinforcing device shown in A-6C;

[0083] Figure 8 Showing from Figure 7 A and 7B have reinforcement devices on the cabin surface;

[0084] Figure 9 An ISO container frame accommodating the prismatic compartment assembly described herein is shown;

[0085] Figure 10 A and 10B show the ISO container and prismatic compartment, as well as the internal reinforcements;

[0086] Figure 11A and 11B A cross-sectional view of a conventional liquefied gas transport vessel is shown. Figure 11B This is a magnified view of the corner of the ship's cabin;

[0087] Figure 12A and 12B The thermal insulation device as described herein is shown;

[0088] Figure 13 A view of a single panel is shown, with one of the outer surfaces removed to reveal the internal components;

[0089] Figure 14A A diagram showing how to connect Figure 13 The upper surface of the panel of the device shown;

[0090] Figure 14B The opposite (lower) surfaces of the panel are shown;

[0091] Figure 15A and 15B A perimeter section of a panel is shown;

[0092] Figure 16 A cross-sectional view of an insulator is shown;

[0093] Figure 17 A cross-sectional view through a perimeter section of a panel is shown;

[0094] Figures 18A to 18D A hexagonal panel arrangement is shown;

[0095] Figure 19 A plurality of internal spacing elements within a hexagonal panel are shown;

[0096] Figure 19A An exploded view of components forming a hexagonal panel is shown;

[0097] Figure 20 An outer surface of a hexagonal panel arrangement is shown;

[0098] Figure 21 A hexagonal perimeter is shown, which when coupled to Figure 20 the surface shown, defines a volume of the panel that can be vented;

[0099] Figure 22A A perimeter of a panel and rim arrangement is shown;

[0100] Figure 22B A cross-sectional view of a perimeter insulation arrangement is shown;

[0101] Figure 22C An abutment of adjacent panels is shown;

[0102] Figure 23 and 24 A plurality of hexagonal panels are shown, coupled to form a single unit or panel group;

[0103] Figure 25A An arrangement of hexagonal panels attached to a hold is shown;

[0104] Figure 25B An arrangement of hexagonal panels attached to an inner hull in a room / hold space (cargo area) of a ship is shown;

[0105] Figure 26 An example vacuum coupled to a panel is shown;

[0106] Figure 27 A transport system for liquefied gas containing the insulation system described herein is shown;

[0107] Figure 28 A transport system is shown Figure 27 A matrix of the transport system is shown;

[0108] Figure 29A , 29B and 29C show plan, side and end views of the disassembled system as Figure 27

[0109] Figure 30 Example dimensions of the system are shown; and

[0110] Figure 31 , 32 and 33 show further examples of insulation and transport according to the invention described herein.

[0111] While the application is susceptible to various modifications and alternative forms, specific embodiments are shown by way of example in the drawings and are herein described in detail. It should be understood however that the drawings and detailed description thereto are not intended to limit the application to the particular form disclosed but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the application as defined by the appended claims.

[0112] No admission is made that any of the prior art references constitute part of the common general knowledge. As used in this specification, the words "comprises", "comprising", and similar words, for example "comprises essentially", "comprises predominantly", "comprises primarily", "comprises principally", "comprises substantially", "comprises virtually" and "comprises mainly" where used in this specification, are not to be construed as excluding the presence of other elements or ingredients. In other words, it is meant to cover "includes, but not limited to". The application is further described by reference to the following examples. It will be appreciated that the claimed application is not intended to be limited in any way by these examples. It will also be appreciated that the application covers not only the individual embodiments described herein, but also combinations of the embodiments described herein.

[0113] The various embodiments described herein are for purposes of illustration only and are not intended to limit the claimed features. These embodiments are representative of appropriate ways in which the claimed features can be implemented. The described advantages, embodiments, examples, functions, features, structures, and / or other aspects of the claimed application can be used individually or in any combination, and are not limited to the specific embodiments described herein. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the claimed application. The various embodiments of the application can suitably comprise, consist of, or consist essentially of, the essential, as well as optional, ingredients, components, features, parts, steps, means, etc. described herein, as well as any additional ingredient, component, feature, part, step, means, etc. present in the art to which the application pertains or any of the additional ingredients, components, features, parts, steps, means described in the background section of this patent. In addition, the disclosure can include other inventions now existing or developed in the future that relate to the application described and claimed in this patent.

[0114] ​It will be appreciated that features of the aspect(s) of the application described herein can be used conveniently and interchangeably with any suitable combination. DETAILED DESCRIPTION

[0115] Figure 1 A cross-sectional view of a ship's hull is shown. Cargo containers 1 are located on the deck 2 of the ship. Multi-layered containers can be loaded on the deck or in the hull and cargo hold for transportation around the world.

[0116] In the cross-sectional view shown, the hull houses a tank 3 which can contain additional cargo in liquid form. In the example shown, the tank is provided with a layer of insulation around the outer surface of the tank and a gap 4 is provided between the tank 3 and the hull structure 5. The gap allows for inspection of the insulation. This arrangement is a conventional arrangement used on ships and involves the application of a sprayed layer of insulating foam to the outer surface of the tank to insulate the contents. Insulating the tank allows the contents of the tank to be maintained at a particular temperature.

[0117] A small gap can occur between the tank and the layer of insulation around its outer surface. If the condensation point of the atmosphere of the gap is higher than the temperature of the outer surface of the tank, the atmosphere of the gap will condense due to the very low temperature of the tank wall facing the layer of insulation. To avoid this, the small gap can be filled with a gas that does not condense at the temperature of the outer tank wall, i.e. <-250 degrees Celsius. Such a gas can be helium (He) or hydrogen (H2). Alternatively, any gas in the gap can be evacuated by introducing a vacuum. The gap can also be left without taking any measures to avoid condensation. In this case, depending on the atmospheric conditions, condensation can occur in the gap, forming a layer of ice on the outer surface of the tank and inside the panel. This layer will grow until the outer surface, facing away from the tank surface, reaches a temperature higher than the condensation point of the atmosphere of the gap. The formation of ice can act as an insulating layer.

[0118] Figure 1 The cargo containers 1 shown in the middle can comply with specific intended international dimensional standards. There are different standards for cargo shipping containers. One standard is the International Organization for Standardization (ISO) standard 668:2020. These standards define the size and dimensions of the containers.

[0119] The advantage of ISO containers for cargo is that they can all be loaded onto a ship and locked securely together with no space between adjacent containers. This maximizes the space utilized on the ship. They can also be conveniently loaded, unloaded and transported around the world at ports set up to specific standards.

[0120] As described herein, the inventors have designed a prismatic tank which can be sized to comply with ISO standards, thereby conveniently allowing its use in the normal chain of transport of conventional cargo. Also as described herein, the new tank arrangement allows the containment of liquefied gases to extremely low temperatures.

[0121] The structure and construction of the tank will now be described.

[0122] Figure 2 A, 2B and 2C show the sub-components that make up the tank body itself. As shown, the construction of the tank is modular and comprises a plurality of perimeter frame sections (as shown in Figure 2 B) and a plurality of substantially flat sections (as shown in Figure 2 C). The frame sections and flat sections come together to form the tank (as shown in Figure 2 A).

[0123] The individual components will now be described.

[0124] Referring to Figure 2 C, the flat sections are shown. These sections are all extruded aluminium flat bodies that extend along the length of each side of the tank. The width of each extrusion, denoted by w in Figure 2 C, determines whether some joints are required between each extrusion to form the side or end faces of the tank surface. As shown in Figure 2 C, two extrusions can make up a side surface of the tank. Similarly, as shown, two extrusions can make up each end face of the tank as well as the top and bottom.

[0125] The extruded flat sections allow for optimised surface geometry to be provided. For example, the outer edges of each flat section can be thicker than the central region to allow for these parts to be more conveniently joined, bonded or welded together, whilst minimising material consumption and weight, whilst maintaining the necessary strength. Other cross-sections of the flat sections can also be provided using conventional extrusion techniques.

[0126] Aluminium advantageously provides the required strength of the surface with minimal weight. It also advantageously provides a tank surface that is not susceptible to corrosion, which is particularly advantageous when the tank is transported by a vessel. Further still, aluminium alloys retain their mechanical properties at low temperatures and therefore allow for convenient manufacture and also strength.

[0127] Turning to Figure 2 B, the perimeter frame sections are shown. The perimeter frame sections define the edges of the prismatic tank and provide the means of joining the side, top, bottom and end surfaces to define the boundary walls of the tank.

[0128] As with the flat sections, the perimeter frame sections can also be extruded, thereby benefiting from the same advantages as described above. In particular, the cross-section of the frame sections can be optimised for strength.

[0129] The frame segments also advantageously allow for optimization of the point or line along which the frame connecting to the adjacent flat segment follows. In particular, by providing extruded frame segments, the integrity of the connection can be very high due to the continuous nature of the extrusion. Furthermore, the cross section of the extruded frame can be optimized for strength, weight, and for the coupling with the adjacent flat segment.

[0130] Reference will now be made to Figure 3 A, 3B and 3C describe the frame segments in more detail.

[0131] Figure 3 A, 3B and 3C show side views of the corners and corner segments. As shown, the corner segments comprise a vertical part extending from the bottom to the top of the tank and two horizontal parts arranged at 90 degrees to each other to define a side edge and an end edge.

[0132] Due to the increase in pressure within the tank that can be caused by evaporation, the tank is susceptible to elevated stress concentrations. It is for this reason that prismatic tanks are generally not used for pressure applications. However, the inventors have determined that using an extruded frame such as that shown in A, the segments, and hence the joints, can withstand very high forces. In particular, the geometry of the frame segments is such that the point or line at which the flat segments are joined (welded) to the frame segments can be kept away from areas of very high stress. Figure 3

[0133] As shown in A, the weld points W Figure 3 p may be moved away from the corners or turning points of the material from which the frame is made. As shown, by moving the weld points from the corner regions of the frame parts by a distance d, the location at which the weld is made is moved away from the regions of maximum stress.

[0134] This advantageously increases the structural integrity of the tank edges, allows for welds with greater integrity, and allows the thickness of the cross section to be optimized for strength and weight.

[0135] Furthermore, moving the weld points of the lines to the flat regions of the tank allows for the use of welding techniques such as friction stir welding (FSW). FSW is advantageous in such tank applications as a highly uniform and continuous weld can be formed between the frame segments and the adjacent flat segments.

[0136] This allows for highly integral corner and edge joints to be formed around the perimeter of the tank.

[0137] As shown in B, the corner segments can be pressed to form curved corners at each of the 4 corners of the tank. The number of corners will of course depend on the chosen tank geometry, and can therefore be greater than 4. Figure 3

[0138] ​​​Furthermore, the same FSW technique can be advantageously used to join together adjacent flat sections.

[0139] Thus, a high integrity tank can be provided formed from extruded sub-components. The simplicity of extrusion allows the tank to be manufactured in a cost effective manner and with high precision. Coupled with the high integrity joint between the modular components forming the tank, a high strength and durable tank can be provided for the oceanic transportation of liquefied gas or the like.

[0140] The tank can be conveniently formed by bringing together a plurality of the above extrusions and then welding them together.

[0141] Figure 4 Side, top and end views of the tank described herein are shown. The various sub-components are represented by the following reference numerals:

[0142] 7 extruded profile corner;

[0143] 8 extruded beam (short);

[0144] 9 extruded corner;

[0145] 10 extruded beam (long);

[0146] 11 extruded panel (bulkhead);

[0147] 12 extruded panel (bulkhead); and

[0148] 13 extruded panel (top / bottom).

[0149] It will be appreciated that other welding techniques can also be conveniently applied to the modular arrangement described herein.

[0150] These drawings describe the constructional details of a tank body containing liquefied cargo or fuel (in a fuel tank application). Aspects applicable to the insulation of the tank body will now be described.

[0151] Figure 5 Sectional views (5A), partial sectional views (5B) and plan views (5C) of the tank described herein are shown. Figure 5 A is Figure 5 A-A' section of C.

[0152] The tank body as described in Figures 2 to 4 is surrounded by an insulation layer 14 positioned against the outer surface of the tank body 15. The tank contains cargo / fuel 16.

[0153] The internal volume of the tank can be an empty space to receive cargo / fuel or can contain a series of perforated transverse members or surfaces 17.

[0154] The plurality of internal surfaces or ribs 17 arranged to extend between the inner walls of the tank can advantageously provide a number of benefits:

[0155] - Firstly, the surfaces or ribs can increase the structural rigidity of the tank body;

[0156] - Secondly, the increased rigidity enables the tank to withstand greater pressure loads both internally and externally;

[0157] - Thirdly, by making the internal structure more robust, the wall thickness of the tank can be reduced and optimised; and

[0158] - The internal structure or ribs can advantageously prevent or reduce the movement of liquid within the tank (sometimes referred to as "sloshing"), which is undesirable when moving the liquid tank.

[0159] Details of the insulation layer 14 are described in more detail below.

[0160] Turning to Figure 6 A, 6B and 6C, these figures show a cross-sectional view of a corner of the tank. Figure 6 B is Figure 6 A cross-sectional view of the cross-section A-A' in A. Figure 6 C shows an enlarged view of a corner of the tank structure. As shown, internal ribs 18 extend around the inner walls of the tank, thereby providing circumferential reinforcement of the tank. The ribs 18 also act to advantageously reduce liquid sloshing motion, but in this example extend through the tank, rather than along the tank as in the rib example shown in A. Figure 5

[0161] In Figure 6 C, the tank wall 19 is shown surrounded by a secondary barrier or insulation layer 20. The insulation layer 20 is arranged to completely encapsulate the tank body (except for the loading and unloading ports), thereby completely insulating the tank body from the external ambient temperature.

[0162] Figure 7 A and 7B show the reinforcement structure within the tank using Figure 6 B and 6C. It will be appreciated that this structure within the tank provides a tank which is extremely rigid. Each rib can advantageously be made from aluminium extrusion or cut and conveniently bolted or welded together to make the structure. The dimensions of these ribs can be deviated at intervals to more efficiently reduce sloshing.

[0163] Figure 8 A cross-sectional view of the tank surface around Figure 7 A and 7B show the tank surface around the structure shown in

[0164] As mentioned above, the novel prismatic tank arrangement described herein can conveniently be arranged to correspond to the dimensions specified in the cargo transport regulations, such as the ISO regulations for shipping containers. ​

[0165] Figure 9 One such example is shown, which contains a prismatic extruded pod as described herein within an ISO container envelope. The pod 21 can be positioned within a container outer frame 22. As shown, the outer frame 22 provides standard attachments 23 which allow such containers to be connected to each other and / or secured to a base such as a ship deck and linked together for large scale transport, for example, on a ship, as Figure 1 is shown.

[0166] Figure 10 A and 10B show such an ISO arrangement and prismatic extruded pod. Figure 10 A also shows optional internal ribs, which in this example extend along the length of the pod.

[0167] The insulation of the prismatic pod and the combination of the insulation and the pod will now be described. It will again be appreciated from the teachings herein that the combination of the pod and insulation can be used for both cargo and fuel pod applications.

[0168] Figure 11A A cross-sectional view through a conventional gas carrier vessel 111 is shown, which is adapted to transport liquefied gas cargo. The gas is liquefied and pumped into a pod within the vessel for long distance transport. In order to maintain the gas in a liquefied state, the pod on the vessel must be kept at a very low temperature, which requires special insulation of the cargo pod.

[0169] The vessel includes a cargo support system 112, which provides support for the cargo pod 113 against the hull of the vessel and within the hull. The pod 113 acts as the primary safety containment barrier of the vessel and is typically formed of steel or aluminium designated for cryogenic applications.

[0170] A barrier-to-barrier space 114 is provided, which defines the space between the pod 113 and another secondary barrier. This can be the inner hull of the vessel and can be another layer of insulation material or insulation of the vessel. In this case, the barrier-to-barrier space provides an accessible space between the outer surface of the pod 113 and the insulation arranged on the surface of the inner hull.

[0171] Alternatively, the insulation can be constructed adjacent to or attached to the pod and itself act as a barrier. In this case, the barrier-to-barrier space will be defined by the distance from the outer surface of the pod 113 and the insulation also acts as a barrier.

[0172] The pod 113 is arranged to contain the cargo of the vessel, which can be various liquefied gases. In one example, the cargo can be liquefied natural gas (LNG) which is kept at a temperature of -163 degrees Celsius. Another example can be liquefied hydrogen which is kept at a temperature of -253 degrees Celsius.

[0173] A secondary protection layer 115 is provided to comply with legal requirements for the transport of liquefied gas. This can be arranged on the surface of the inner hull or by an alternative means. In the event of a failure or leak in the primary tank 113, liquefied gas can flow into the space, for example the inter barrier space 114, and be contained by the secondary protection layer 115. This layer prevents the liquefied gas from contacting the hull, which can cause fatal failure of the hull due to the extremely low temperature of the liquefied gas.

[0174] Figure 11A The illustrated arrangement is a common structure for a vessel for transporting liquefied gas, for example LNG. These gas carrying vessels provide a safe primary tank to contain the cold liquid and a secondary back-up layer system in the event of a primary tank leak or failure.

[0175] A disadvantage of this construction of LNG carrying vessels is the construction time and the resulting costs, and the challenges associated with the logistics of the construction process. As described herein, the construction of such vessels can be slow because the tanks cannot be installed until the vessel structure and the secondary barrier are first installed on the hull surface. If the insulation layer is adjacent to or attached to the tank and also serves as the secondary barrier, the tank can be installed directly after the hull construction is complete.

[0176] An advantage of the present invention is that the components of the vessel can be installed in parallel, reducing the overall construction time of a liquefied gas carrying vessel.

[0177] Figure 11B A close-up view of a corner of the conventional arrangement shown in Figure 11A Here, the inter barrier space 114 and the secondary insulation layer 115 are more clearly visible.

[0178] Figure 12A And 12B A side view and a cross-sectional view of an embodiment of the insulation arrangement described herein are shown (respectively).

[0179] Figure 12A A general arrangement of the insulation arrangement is shown. The arrangement 116 comprises a first layer 117 facing inwards and a second layer 118 facing outwards. The inwards facing layer is arranged in use to face or abut a tank containing liquefied gas (for example Figure 11A The primary enclosed tank 113 shown in

[0180] The opposing surface 118 is arranged in use to face outwards to the inter barrier space 114 or the hull (see Figure 11A And 11B ), i.e. outwards from the cold cargo.

[0181] Figure 12BA device is shown. As shown, the first and second layers 117, 118 are spaced apart by a distance d, thereby defining a cavity or space 119. Discrete elements 1110 are located between the two layers or surfaces 117, 118 and maintain the space between the two layers.

[0182] Figure 12A And 12B Also shown are undulations 1111 which are formed in one or both surfaces and which increase the structural strength by increasing the rigidity of the layers and additionally and advantageously accommodate thermal expansion and contraction of the panel surface.

[0183] Figure 12A And 12B Also shown is a vacuum valve 1112 which allows air communication between the space within the device and the external environmental conditions. The valve 1112 is arranged to receive an air pump (vacuum pump) which is operable to reduce the pressure within the space between the layers to or close to a vacuum. This is discussed further below.

[0184] Figure 13 Another view of the unit shown in Figure 12A And 12B is shown. Here the internal arrangement of the unit or panel is shown. As shown, a series of undulations 1111 are arranged across and along the length of the panel. Reference is made to Figure 14A , which shows a corresponding profile 1111B which fits within the undulating profile 1111 when the two parts are brought together. Thus, the undulations can increase the rigidity of the panel.

[0185] Returning to Figure 13 In one embodiment, the discrete elements which space the surfaces 117, 118 are in the form of a plurality of elongate members 1114A, 1114B, 1114C and 1114D. It will be appreciated that any number of elements can be used. The discrete elements extend from one end of the panel to the other, providing support for them along the entire length of the two surfaces.

[0186] In order to allow air movement within the panel and between the two opposing layers, each discrete spacing element (1114A-1114D) is provided with a plurality of holes 1113 which allow air to move freely within the panel. Thus, when air is drawn in through the valve 1112, the entire space within the panel can be evacuated and a vacuum can be formed.

[0187] Advantageously, by forming a vacuum in the panel rather than using a thermal insulating material such as foam, the thermal insulating properties of the panel can be significantly improved. Furthermore, the weight of the panel can also be significantly reduced as the space between the layers of the panel is neither material nor evacuated air.

[0188] The two faces or layers 117, 118 are then structurally supported from each other by a plurality of discrete support elements, Figure 13 An example is shown in Fig. 1 1. As an example, the layers and support elements can be made from aluminium by extrusion. Thus, when air is drawn away from the panel and a vacuum is established, the panel is able to support or resist forces caused by atmospheric pressure acting on the two surfaces 117, 118 and the perimeter 1 1 15 (see Fig. 1 1). The panel is also able to support any external loads applied to the panel, which can be caused by the weight of liquid acting on the panel caused by, for example, a leak or rupture of the cabin. Figure 17

[0189] Figure 14A 14B An example of a panel structure using extruded layers 117, 118 to form the two opposing layers of the panel is shown. In an embodiment, extruding each layer from aluminium advantageously allows the layers to be formed to any practical length and width. It allows each layer to be formed in a cost effective and simple manner, and furthermore allows the undulations 1 1 1 1 to be formed quickly and easily.

[0190] The perimeter of each panel will now be described with reference to Figure 15A 15B

[0191] As shown in Fig. 1 1, the perimeter P extends around the sides of the panel and provides an impermeable seal once joined to the edges of each of the two opposing layers shown in Figs. 1 1 and 1 2. The ends have a profile complementary to the undulations 1 1 1 1. The panel is formed by welding the perimeter P to the two layers, thereby forming a sealed interior space bounded by the perimeter around the edges and the two opposing faces. Figure 15A Figure 14A 14B

[0192] As an example, the perimeter of each panel will now be described with reference to Figs. 1 1 and 1 2. The perimeter forms the side boundary of the panel. Once the inward facing surface and the outward facing surface are coupled to the perimeter (for example by means of welding), a sealed volume is thereby formed. Air can be evacuated from the volume and a vacuum created inside the device. Figure 15A 15B The perimeter is shown as adjacent but unconnected components P1 and P2, with a space S between the two perimeter components. This space can be bridged with a different material having a lower heat transfer performance than the material used for P1 and / or P2 (as described below). Thus, a thermal insulating portion can be formed.

[0193] Figure 15B The perimeter can advantageously be metal, which can be conveniently welded to the two layers to provide a non-permeable surface around the perimeter of the panel.

[0194]

[0195] ​​​​​​​​​Because the inward-facing panels will be close to the cool main cabin, the temperature of the inward-facing surfaces will be significantly lower than the temperature of the outward-facing layers, which may be, for example, at ambient temperature or close to seawater temperature.

[0196] In one embodiment of the device for containing liquefied hydrogen, the inward-facing surface can be at a temperature of <-250 degrees Celsius, while the outward-facing surface can be at a temperature of >0 degrees Celsius. Therefore, a significant temperature difference or temperature gradient exists on the panel.

[0197] Any suitable material can be used to form the layers of the panel and the individual support elements. For example, aluminum, which has low density and can be used with undulations to form a robust structure, can be used. However, aluminum has a thermal conductivity of approximately 121 W / mK, which adversely allows ambient temperature to be conducted through the material to the cold side of the panel (and the liquefied gas chamber).

[0198] Therefore, insulation can be used to prevent heat transfer between the two surfaces. This is in Figure 16 An example is shown.

[0199] Figure 16 A first layer 117 and a second layer 118 are shown, along with a single discrete support element 1114 extending therebetween. The support element 1114 is formed by a first portion 1116 extending from the first layer and a second portion 1117 extending from the second layer. These two portions can be joined together by a heat-insulating or heat-breaking portion 1118.

[0200] The heat insulation portion 1118 can be made of a different material than the two portions 1116 and 1117. For example, layers 117 and 118 and portions 1116 and 1117 can be formed of aluminum. In one example, portions 1116 and 1117 can be integrally formed with layers 117 and 118, for example, by extrusion. Alternatively, they can be welded at the intersections of the portions and the corresponding layers.

[0201] exist Figure 16 In the example shown, the insulation 1118 can be part of stainless steel, which has a much lower thermal conductivity than the adjacent aluminum (e.g., about 12 W / mK instead of 121 W / mK). Therefore, heat is confined to prevent it from being transferred directly along the discrete components, and is instead prevented from being transferred through the insulation.

[0202] In an arrangement where stainless steel is used for the insulation section 1118 and aluminum is used for the two sections 1117 and 1116, the connection can be made using known welding techniques for connecting stainless steel to aluminum. Other suitable joining processes can also be applied.

[0203] The thermal breaks 1118 can alternatively be made of a polymer such as rubber, POM, PTFE or PEEK suitable for low temperature applications. The connection can be by adhesive bonding or vulcanized bonding.

[0204] As Figure 15A and 15B indicated, it can also be necessary to have thermal breaks 1118 around the perimeter of the panel. As Figure 16 indicated, a similar arrangement can be used. It is important that the perimeter also experiences lateral forces as the internal air within the panel is evacuated, atmospheric pressure acting on the perimeter. Thermal breaks are therefore required to resist lateral or transverse movement.

[0205] Figure 17 An example of how the perimeter 1115 can fit into a thermal break is shown. Here the cross section of the thermal break 1118 is triangular, meaning that atmospheric pressure acts to bias the thermal break into the gap between the first and second portions of the perimeter section 1115. The thermal break 1118 can alternatively be a welded plate or have other geometrical shapes.

[0206] The thermal breaks 1118 can be located at any distance from the upper or lower layer 117, 118.

[0207] In yet another example, the discrete support elements can be formed of wood such as plywood, bamboo, cardboard or other materials preferably having low heat transfer properties.

[0208] Figure 17 Also shown is a perimeter of a layer that can be used to conveniently allow two adjacent panels to be welded together. In such an arrangement, one or more adjacent panels can be sealed together by an impermeable welded joint to form a single internal volume or space. For example, when two adjacent panels abut each other, a weld can be applied to the upper and lower edges of the panels.

[0209] As mentioned above, the shape of the individual panels can be rectangular or square, allowing adjacent shapes to be conveniently tessellated and joined together (for example by welding). Other shapes including triangles can also be used. Combinations of different shapes can be used depending on the geometry of the cabin or room / holding space to be thermally insulated.

[0210] Figures 18A to 18C An alternative tessellation panel in the form of a hexagonal shape is shown. Advantageously, hexagons can be tessellated and thermal expansion is uniform when measured radially outward from the centre of the hexagon. Figure 18D An air exhaust valve is shown that allows air to be extracted to form a vacuum inside the hexagonal panel.

[0211] The interior of the hexagonal panel will now be described with reference to Figure 19

[0212] ​The hexagonal panel can comprise a plurality of discrete support elements arranged in a range of different distributions and configurations. In Figure 19 In the example shown, the support elements are not elongate strips of material running along the panel or concentric rings spaced radially across the panel, but are in the form of a plurality of pillars.

[0213] The pillars can for example be cylinders or hexagonal pillars which extend from the inward and outward facing surfaces as Figure 19 shown. The pillars can be placed directly on the inward and / or outward facing panel or on a material support layer applied on the inside of the respective layer. This material support layer can advantageously have low heat transfer properties. When a vacuum is drawn in the panel, the pillars can provide the support needed to maintain the two surfaces or layers apart. Low thermal conductivity means that heat transfer across the panel is minimised.

[0214] As Figure 19 shown, the pillars can also be in the form of hexagons, which advantageously allows these independent pillars to tessellate within the body of the hexagonal panel and extend across the area of the panel. Thus, both vertical and lateral loads can be accommodated.

[0215] Each pillar can be constructed with an intermediate insulating portion in reference to the description of Figure 16 However, it can also be advantageous to use a single continuous material with low thermal conductivity, such as wood (e.g. plywood or wood composite), bamboo, cardboard or stainless steel. Thus, an insulating portion which increases simplicity and reduces manufacturing costs can be used.

[0216] Figure 19A Sub-components which make up the hexagonal panel are shown. As shown, a hexagonal array of individual hexagonal pillars is located between the upper and lower surfaces of the panel and within the outer perimeter.

[0217] In an alternative optional arrangement, the pillars themselves can also be filled with insulating material, such as expanded foam, perlite, etc. These pillars can each be wholly or partially filled with such material, which can advantageously increase the strength and / or thermal properties of the panel. All or a subset of the pillars can be filled, whereby a balance between strength, weight and thermal performance can be achieved.

[0218] Figure 19 and 20 Internal details of the hexagonal panel are shown. Figure 20 Two perimeter portions PI and P2 corresponding to the perimeter described above in reference to Figure 15B are also shown. Figure 21 A perimeter 1122 of the hexagonal panel is shown.

[0219] Figure 19 Each pillar shown in the middle can additionally be provided with holes, slots or apertures which allow air to communicate in and out of each pillar. Thus, air can pass Figure 18DThe valves shown in the middle are extracted from each column to create a vacuum inside the entire panel and each column. The differential pressure inside the panel can be avoided and the thermal performance of the vacuum maintained.

[0220] The requirement for a hexagonal panel is still that the entire perimeter is airtight (impermeable to air flow) while maintaining the required thermal performance between the inner facing surface and the outer facing surface. This can be achieved with reference to Figure 22A .

[0221] Figure 22A An embodiment of a hexagonal panel device is shown.

[0222] The panel comprises an inner facing surface 117 and an outer facing surface 118 and additionally (see Figure 22B ) two lips or rims R i and R o .

[0223] The rims or lips are additionally shown in Figure 22B where it can be seen that the rims extend from the outer facing surface and around the perimeter of the panel. The function of the rims is described as follows.

[0224] The rims are angled relative to the vertical side surface of the perimeter of the panel as shown by angle a (greater than 90 degrees). As shown in Figure 18C and 20 , the panel is comprised of an outer facing component P1 and an inner facing component P2. A separation S is provided between the two components forming the opposite surfaces of the hexagonal panel.

[0225] In order to form a seal around the perimeter of the panel, a thin layer of stainless steel 1120 is coupled to the outer perimeter of the panel to overlap the separation S and to both components P1 and P2.

[0226] The stainless steel layer can advantageously be incorporated into an inner lining of wood or similar material within the perimeter of the panel and itself extend across the separation S. The provision of a backing layer can allow the stainless steel layer to be very thin and thus simultaneously provide:

[0227] (a) the required airtight surface around the perimeter of the panel; and

[0228] (b) the required thermal insulation around the perimeter of each of the panel.

[0229] The stainless steel can extend through the entire depth of the panel, i.e. from L1 to L2 in Figure 22B .

[0230] Figure 22B A thin stainless steel layer and backing surface as described above is shown. The thickness of the materials forming the device shown in Figure 22A may be selected according to the desired thermal and structural performance of the panel. For example, the dimensions can be in the following ranges:

[0231] The outer facing layer thickness ranges from 0.2mm to 1mm

[0232] The inner facing layer thickness ranges from 0.2mm to 1mm

[0233] The separation S ranges up to 200mm

[0234] The insulation layer thickness is less than the thickness of the adjacent material, for example 0.8mm, while the adjacent material thickness is 1mm.

[0235] Figure 22C The outer rim R0 and inner rim R are shown i to function.

[0236] As shown, two adjacent insulation devices Al and A2 abut to form part of a tessellation of insulation devices of the insulation system. In tessellation, the two adjacent devices Al and A2 will be in linear contact along the perimeter of the hexagonal shape.

[0237] Here, at point J in Figure 22C a weld bead or weld can be formed to weld the two devices together. The weld itself forms an airtight seal, preventing any air from passing from the cold side of the device to the ambient side. When the device is connected to the tank, the weld is on the ambient side of the panel, and conversely when the device is arranged on the hull, the weld is on the cold side of the panel.

[0238] The angle a of the rim allows for some flexibility and mobility of the adjacent devices Al and A2. Thermal contraction of the cold side of the panel will tend to pull the two adjacent rims apart. On the ambient side of the panel, thermal expansion will tend to push the adjacent rims together.

[0239] Advantageously, the cold side of the panel or the ambient side of the panel will not be rigidly coupled to the tank or hull to allow for thermal movement of the insulation device relative to the tank / hull surface when the tank is emptied (and possibly warmed up) and refilled (and thus cooled). Advantageously, the connection to the tank or hull is flexible and allows for relative movement between the tank / hull and the panel.

[0240] Because the panels are not firmly attached to the cabin, and because the edges of the panels are on their cold side, there will be a small gap between the cabin surface and the thermal panels. If its condensation point is higher than the temperature of the outer surface of the cabin, the atmosphere of this gap will cause condensation due to the very low temperature of the cabin wall facing the thermal layer. To avoid this, the small gap can be filled with a gas that does not condense at the temperature of the outer cabin wall, i.e. <-250 degrees Celsius. Such a gas can be helium (He) or hydrogen (H2). Alternatively, any gas in the gap can be evacuated by introducing a vacuum. The gap can also be left without taking any measures to avoid condensation. In this case, depending on the atmosphere, condensation can occur in the gap, thus forming a layer of ice on the cold surface of the cabin outer surface and the panel. The layer will grow until the outer surface of the layer, facing away from the cabin surface, reaches a temperature higher than the condensation point of the atmosphere of the gap. The formation of ice can act as a thermal barrier preventing further ice formation.

[0241] To fully optimize the thermal performance, the gaps formed between adjacent panels can be filled with thermal insulation material. For example, the gaps can be filled with polyurethane, mineral wool, EPS (expanded polystyrene), or other thermal insulation material that can be conveniently positioned in the gaps to fill the space. Alternatively, a vacuum can be introduced in the gaps.

[0242] Figure 23 and 24 A plurality of hexagonal panels coupled together are shown for attachment to the outer surface of the inner hull or cabin of a vessel. In such an arrangement, a non-permeable seal around the perimeter need only be around the outermost perimeter of the entire arrangement, not the perimeter of the individual panels. Thus, a single internal volume of the arrangement can be provided, and a single vent valve used. This allows for faster installation and venting of the arrangement.

[0243] In the case where adjacent groups or panels are clustered on one surface, any gaps between adjacent groups can advantageously be filled with thermal insulation material, such as expanded foam as described above, or the like. Alternatively, a vacuum can be introduced in the gaps.

[0244] In addition, it facilitates convenient checking and monitoring of the vacuum level within the arrangement, which is important for the thermal performance of the arrangement. In such an arrangement, only a single valve need be checked to determine the internal pressure of the plurality of connected panels. A pressure gauge can additionally or alternatively be installed.

[0245] Figure 25A Installation of a hexagonal arrangement on the outer surface of a cabin is shown.

[0246] Figure 25B Installation of a hexagonal arrangement of the inner hull in a room / holding space (cargo area) of a vessel is shown.

[0247] Figure 26The vacuum connection and associated conduit of the vacuum valve connected to the panel through which air can be evacuated is shown. It will be appreciated that a plurality of individual panels or groups of panels can be connected to a single vacuum pump to form one or more vacuum sections. For example, a manifold arrangement can be provided to allow for convenient coupling and maintenance.

[0248] Whilst the above examples relate to hexagonal panels, it will be appreciated that the same approach can be used for other shapes which can be tessellated. For example, this can be square or triangular panels. Depending on the geometry of the hold to be insulated, a combination of different shapes can be used and tessellated together to provide a complete barrier covering the entire surface of the hold or the inner surface of the hull. It also follows that the edge and perimeter insulation arrangement can equally be used for different panel shapes.

[0249] Temperature monitoring and / or pressure monitoring can be used to enable monitoring of the insulation arrangement.

[0250] Each panel or plurality of panels defined by the impermeable seal can be connected to a pressure control and monitoring system and via a vacuum valve 1113 vacuum pump. The difference between the defined vacuum pressure, a default value and the actual pressure will be monitored. The vacuum pump connected to the grid or group of panels will activate and restore the default vacuum pressure when required.

[0251] Alternatively, temperature can be used as a monitoring parameter instead of or in addition to pressure. Temperature measurement can be achieved using a sensor such as a thermocouple or a passive sensor such as an infrared (IR) camera to monitor temperature variations between the panels and against a desired operating temperature. If the temperature rises above a predefined default value, this indicates a loss of vacuum. The vacuum pump connected to the grid of one or more panels will activate and restore the default vacuum pressure when required and if required.

[0252] It will be appreciated that the insulation arrangement described herein can be used to allow the transport of liquefied gas in cargo applications as described above, i.e. in the case of large volume holds on board vessels specifically constructed for the carriage of liquefied gas. The inventors have identified that the insulation panel arrangement can also be used for other related applications. For example, the panels can be installed on the hold itself or, if the hold is not insulated, on the walls / cabin walls of the room / holding space in which the un-insulated hold is placed.

[0253] Additionally or alternatively, LNG fuel tanks can be implemented using the insulation arrangement described herein.

[0254] Additionally or alternatively, liquid hydrogen (LH2) fuel tanks can be implemented using the insulation arrangement described herein. Thus, clean fuel can be used by providing such insulated fuel holds which can contain liquefied hydrogen.

[0255] The above discussion has focused on the use of insulation in purpose-built cargo ships with large holds or several large holds as shown in Figure 25 and fuel holds (for LNG / LH2). However, it is also possible to implement a modular cargo arrangement as now described with reference to Figures 27 to 30

[0256] Figure 27 A liquefied gas transport device containing the insulation as described herein is shown. The transport device is arranged within the dimensions of an ISO standard container, such as but not limited to 20, 40 or 45 feet long, including high cube freight containers of the type used for transporting cargo on ships or any other suitable skid-like structure.

[0257] As Figure 28 shown, the outer structure 1127 is arranged so that individual transport devices can be coupled together. An array of individual liquefied gas transport devices can then be secured together, for example within or on the deck of a cargo ship for transport. In Figure 28 the array of individual liquefied gas transport devices are coupled together to form a hold array.

[0258] The insulation portion of the device will now be described with reference to Figures 29 and 30.

[0259] Figure 29A A plan view of the device is shown. Figure 29B A side view of the device is shown, Figure 29C an end view is shown.

[0260] Figure 29A An exploded view of the individual sections that make up the insulation layer around the hold is shown. The hold 1128 is arranged to contain a liquefied gas, such as hydrogen (LH2) or LNG. The hold 1128 is surrounded by an insulation layer that itself is formed of sections.

[0261] The hold 1128 can be surrounded by end sections 1129A, 1129B and two sleeve sections 1130A, 1130B. The sleeve sections 1130A, 1130B are arranged to slide over the length of the hold. The hold is then "sealed" by locking the end sections 1129A, 1129B to form an envelope around the hold 1128. With reference to Figure 27 the closed hold is shown with an access port 1131 for loading, unloading.

[0262] As described herein, the insulation layer can be in the form of a mosaic of individual panels. However, Figures 29A-29C the sleeve of the device shown allows for the use of longer sections of insulation layer with the same vacuum internal cavity and is conveniently manufactured. As described herein, spacer elements can be used to provide the structural support required for insulation when a vacuum is drawn within the layer.

[0263] ​The spacing elements can be discrete elements or can be elongate members extending along the length of the sleeve (and within the space defined between the cabin-facing layer and the outward-facing layer). This allows for convenient manufacture, such as by extrusion.

[0264] Figure 30 Side, end and plan views of the device are shown having suitable dimensions to conform to the dimensions of shipping containers used in freight ships and international transport. Thus, the device can be conveniently worked using conventional logistics systems without the need for special equipment or geometry for loading and unloading.

[0265] In another arrangement, the cabin 1128 can be cylindrical and the corresponding sleeve is cylindrical to surround the cylindrical cabin. Then, the end portions would be two opposing concave insulating "caps" on either end of the cabin.

[0266] For example when a single container is used, the device described herein relating to vacuum, temperature sensing and evaporation handling / management can be conveniently arranged within the outer bounds of the container. Alternatively, for example when multiple containers are used together, multiple containers can be connected to a master container which houses the control and monitoring equipment for the vacuum, temperature sensing and evaporation devices. Alternatively, this can be integrated with other relevant on-board control devices.

[0267] It will also be appreciated that each container can be provided with suitable conduits and connectors allowing for vacuum to be drawn from a single vacuum source from multiple container insulation devices. Electrical connections can similarly be provided for passing power and temperature / pressure information between containers. Thus, a fully modular container system can be achieved.

[0268] As mentioned above, the invention described herein can also be used for fuel tank applications of a ship.

[0269] In any of the above constructions, the device can comprise an evaporation management system which limits the increasing pressure developed in the cabin as liquid evaporates to gas, ensuring that it remains within safe levels. This can include re-liquefaction for re-injection.

[0270] Reference Figure 31 , 32 and 33 set out yet further examples of insulation and transport in accordance with the invention described herein.

[0271] The above described insulation device is formed from a plurality of discrete units which can be closely packed on the cabin surface and / or the hull surface as described above.

[0272] This is further illustrated with reference to Figure 31 , Figure 31A cross-sectional view of a liquefied gas carrier vessel is shown, including the superstructure of the vessel above the cargo containment tank(s). Here, the vessel 32 includes a tank 33 (which is a main barrier: self-supporting, prismatic, IMO independent tank Type A, Type B, or optionally a new tank design) in which liquefied fuel is loaded and contained during transport. The tank 33 is supported within the structure of the vessel 32 by a plurality of support members or "legs" 34. The support members 34 (which are cargo tank supports: a special design for the extreme temperature of LH2 (-253 degrees Celsius) at which the cargo tank resides) provide support for the cargo tank 33 and also provide a thermal break between the cold tank and the lower structure and surface of the hull. This is described further below.

[0273] Figure 31 A primary insulation layer 35 is also shown, which is arranged proximate to and coupled to the tank 33, as described above with reference to the panel. A secondary insulation layer 36 is also shown, which can be arranged proximate to the hull and coupled to the inner hull or hull. The independent secondary insulation layer 36 provides redundancy and represents an additional layer of risk mitigation.

[0274] Hydrogen appears as LH2 in liquid form at -253 degrees Celsius. Therefore, containment of LH2 will require maintenance of cryogenic temperatures, i.e., <-250 degrees Celsius. Nitrogen is liquefied (or boiled) at -196 degrees Celsius. In order to be able to use N2 for monitoring / monitoring in the gap 37 between the primary insulation layer 35 and the secondary insulation layer 36 on the hull or inner hull wall, the temperature in the gap 37 must be above the boiling point of N2. Therefore, tank top insulation, i.e., the primary insulation layer 35, is required.

[0275] The primary insulation layer 35 can be polyurethane (PU) sprayed foam, vacuum panel, PU panel with plywood, or any other suitable insulation material. Similarly, the secondary insulation panel (if applied) can be polyurethane (PU) sprayed foam, vacuum panel, PU panel with plywood, or any other suitable insulation material. The secondary insulation layer 36 can cover the entire containment space and mask the tank supports.

[0276] In order to reduce the thermal efficiency requirements of the described and primarily consisting of the primary insulation layer and secondary insulation layer (if applied) insulation containment system, a cooling device can be installed in the tank or main barrier 33 itself. This can provide redundancy and represents another additional layer of risk mitigation. Such a cooling device can include a cryogenic refrigerator with an internal heat exchanger.

[0277] Perfect contact between the primary insulation layer and the compartment, and between the secondary insulation layer and the (inner) hull, is unlikely to be achieved. Therefore, small separations will occur between the respective insulation panels and surfaces, creating gaps. When the compartment bears loads such as LH2, the gap between the compartment and the primary insulation layer 35 will maintain a temperature slightly above the load temperature. If this gap is filled with air containing oxygen and nitrogen, these two components will condense at -183 and -196 degrees Celsius, respectively, forming ice.

[0278] The gap (VbT) between adjacent surfaces of the compartment and the main insulation panel can be as follows: Figure 31 Provided as shown (in) Figure 32 This is referred to as V1. Since the temperature in VbT / V1 will be below the boiling / condensation point of an atmospheric mixture of O2 and N2, condensation will occur, thus forming ice. To prevent this, the void could be filled with a gas whose boiling / condensation point is lower than the temperature in the void (VbT / V1) itself. Two gas candidates are helium (He) (which boils / condenses at approximately -269 degrees Celsius) and hydrogen (H2) (which boils / condenses at approximately -253 degrees Celsius). A third option is to create a vacuum in the void VbT / V1. In each of these three cases, the contents / atmosphere of the void / cavity prevent condensation and ice formation. It will be recognized that there is no gas at all in a vacuum. Alternatively, the void could be filled with a gas with a temperature above -253 degrees Celsius. This could be a mixture of oxygen or nitrogen. Since the temperature in the void VbT is below the boiling / condensation point of the oxygen and nitrogen mixture, the resulting condensation will lead to ice formation. This process can be allowed to continue until the ice layer has developed to a sufficient thickness and heat capacity to lower the temperature in the voids below the condensation point of the atmosphere in the voids (VbT / V1). At this point, condensation and further ice formation will cease.

[0279] The gap between the insulation panel and the hull is not affected by such low temperatures. This gap can be filled with air, nitrogen, or helium.

[0280] Therefore, a multi-layered insulation system 38 can be formed, with the lower layers starting from the cabins inside the ship. (This is a reference.) Figure 32 As shown, Figure 22 is a passage Figure 31 A cross-sectional view of a portion of the insulation layer shown.

[0281] Multi-layer insulation systems can be divided into the following layers:

[0282]

[0283] Table 1

[0284]

[0285] Table 2

[0286] The inventors have determined that the lowest thermal performance is achieved with a polyurethane / polyurethane pairing, while the best thermal performance is achieved with a plurality of (mosaic) panels / plurality of panels (as described with reference to Figures 1 to 20 Furthermore, the vacuum arrangement in such panels provides the best thermal performance.

[0287] Reference will therefore be made to Tables 1, 2 and Figure 32 It is recognised that a complex thermal arrangement can be provided for a container according to the invention described herein.

[0288] Advantageously, the thermal performance of each layer can be optimised for a particular cargo. Furthermore, manufacturing and installation can be simplified and adapted to form a plurality of void layers. Lower manufacturing tolerances allow for higher tolerances in the hatch and hull geometry, while providing additional void layers.

[0289] Figure 33 A support member or "foot" 34 is shown in Figure 31

[0290] The support member 34 provides a support function for the hatch, allowing it to rest and slide after thermal expansion / contraction. It also acts as a thermal break, to prevent heat from the surrounding environment conducting to the hatch. Furthermore, in order to maintain the integrity of the voids described above, the perimeter of each support or foot must be sealed to prevent gas from escaping, entering or losing vacuum.

[0291] This is achieved using a load bearing thermal break main member 40. It sits on the lower surface against the hull and its associated structural members and on the upper surface against the hatch.

[0292] As described above, helium or other suitable gas can be used in the voids between the hatches as a mitigation measure to prevent condensation and ice formation. In such an arrangement, an additional helium supply system, for example, can be provided and thus a piping / valving arrangement to the individual voids can be provided. The perimeter of each void can then be sealed to prevent the selected gas, such as helium, from entering / flowing out.

[0293] Figure 33 The coupling between the hatch and the hull lower surface, i.e. the way in which the hatch is both supported and importantly thermally insulated, is shown.

[0294] Figure 33 A plurality of support members 34 is shown in Figure 31 As shown, the foot arrangement includes a thermal break main member 40, which provides the connection between the hatch wall 33 and the hull. This can be made of any suitable material, including for example wood. Aspects of the invention described herein include the arrangement described in Figure 33 wherein one or more components can optionally be included. ​

[0295] As shown, the primary insulation layer 35 is arranged to follow the side profile of the steel support structure 41 extending from the thermal break 40 to the tank 33. The profile of the layer 35 provides thermal insulation continuity around the leg structure.

[0296] To provide a gas seal to seal the thermal bridge / tank support 40, a metal welded cover or cap 42 is welded to the inner surface of the metal outer layer 43 of the insulation panel or layer 36. The weld surrounds the leg, thereby providing a gas seal to maintain the integrity of the void 37, which, as mentioned above, can be filled with an inert gas such as nitrogen.

[0297] The inventors have also determined that the panels and insulation arrangements described herein, including multiple insulation layers and void arrangements, can also be applied to spherical tanks, in effect a football or long spherical shape, wherein each planar surface of the sphere corresponds to the panels described herein. The panels can include various numbers of sides, including pentagons and hexagons, each welded or coupled together.

[0298] Viewed from another aspect, there is provided a modular insulation arrangement for a ship, the arrangement comprising one or more tessellated insulation units as described herein arranged against or proximate to a cargo tank of the ship and defining a primary insulation layer and a secondary insulation layer spaced from the first layer and defining a space therebetween.

[0299] The second layer can also be a plurality of tessellated insulation units or layers or polyurethane (e.g. sprayed). If the arrangement is not for LH2 but for example LNG, then the second insulation layer can not be required.

[0300] The gap or cavity between the one or more tessellated insulation units and the cargo tank of the ship can be filled with a gas selected from helium or hydrogen, or alternatively a vacuum can be applied.

Claims

1. A prismatic tank for containing a liquefied gas, the tank comprising a plurality of substantially planar side walls defining two opposite end portions, two opposite side portions and an upper surface opposite a lower surface, the planar side walls defining a volume for containing a liquefied gas, the prismatic tank further comprising edge portions at the intersections of the planar side walls and an outer insulation layer arranged on the outer surface of the substantially planar surfaces and on the outer surface of the edge portions, wherein, The edge portions and the flat side walls are extrusions, and wherein the thermal insulation layer is in the form of a modular thermal insulation arrangement comprising one or more tessellated thermal insulation units, each unit comprising an inwardly facing first layer and an outwardly facing second layer spaced apart from the first layer, the two layers defining a space therebetween, and one or more spacing members extending between the first and second layers, and wherein the surfaces defining the first layer, the second layer and an outer perimeter extending around the arrangement are gas impermeable surfaces.

2. The prismatic pod of claim 1, wherein, The extrusions are of a common material.

3. The prismatic pod of claim 2, wherein, The material is aluminium or an alloy thereof.

4. A prismatic capsule according to claim 1 or 3, wherein The flat side walls are formed from a plurality of extrusions welded together.

5. The prismatic pod of claim 1, wherein, Each edge section has a cross-sectional shape having a first edge for connection to a first side wall and a second edge for connection to an adjacent side wall, the first and second edges being arranged at 90 degrees to each other, and wherein the first and second edges define a weld line along which a side wall can be welded.

6. The prismatic pod of claim 5, wherein, The weld lines are each displaced at least 10 cm from the intersection at which the first and adjacent side walls would meet.

7. The prismatic pod of claim 1, wherein, The cross-section of the edge portion is in the form of two perpendicular portions for connection to the associated flat side wall, and an intermediate portion connecting the two perpendicular portions, wherein the intermediate portion is arranged at 45 degrees to each of the two perpendicular portions.

8. The prismatic pod of claim 7, wherein, A radius is provided at the point at which the intermediate portion meets the perpendicular portions.

9. The prismatic pod of claim 1, wherein, The edge portions and flat side walls are connected together by friction stir welding.

10. The prismatic pod of claim 1, wherein, The thermal insulation layer comprises a thermally insulating foam.

11. The prismatic pod of claim 1, wherein, The thermal insulation layer is in the form of a plurality of tessellated thermal insulation panels.

12. The prismatic pod of claim 1, wherein, The space between the first and second layers and the surfaces defining the outer perimeter of the arrangement define an internal volume of the arrangement, and wherein the spacing members are arranged, in use, to resist atmospheric pressure acting on the surfaces when the internal volume is evacuated of air.

13. The prismatic pod of claim 1, wherein, The prismatic pod is in the form of a pressure vessel.

14. The prismatic pod of claim 13, wherein, The prismatic pod is configured to contain a pressure in excess of 2 barg.

15. A prismatic capsule according to claim 13 or 14, wherein Further comprising internal longitudinal and / or transverse reinforcing support members extending between the inner surfaces of the pod.

16. The prismatic pod of claim 1, wherein, The prismatic pod is contained within an ISO container frame conforming to ISO dimensional regulations.

17. The prismatic pod of claim 1, wherein, Further comprising a perimeter frame which allows selective coupling to like frames such that a plurality of prismatic pods can be coupled together in a stacked or matrixed formation.

18. The prismatic pod of claim 1, wherein, Comprising an inlet and an outlet port to allow cargo and / or fuel to be loaded into and removed from the pod.

19. An array of prismatic pods comprising a plurality of prismatic pods as claimed in any of claims 1 to 18.

20. The prismatic pod array of claim 19, wherein, The plurality of pods are in fluid communication with each other to allow loading and unloading to be carried out simultaneously and / or sequentially.

21. A fuel pod for a marine vessel in the form of a prismatic pod as claimed in any of claims 1 to 18.

22. A fuel tank for a marine vessel as claimed in claim 21, characterised in that, Further comprising a collection pod or drip tray arranged around the base of the pod and extending partially around the lower perimeter of the pod and partially towards the top of the pod.

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