Equipment for the storage and transportation of gas

Abstract

A gas carrier vessel having a hull and a tank received longitudinally within the hull, and a method of constructing the tank within the hull. The vessel is designed to transport fluids such as hydrogen or other gases and liquids. The tank has multiple layers that are not connected to adjacent layers. The tank contacts the vessel at the top and bottom. A top connection, e.g., a connection to the deck structure, supports the tank to prevent sinking. The tank may be substantially the length of the vessel and located between a forward bulkhead and an aft bulkhead. Two tanks may be placed adjacent to each other and separated by a longitudinal bulkhead. Each layer has a forward end cap and an aft end cap constructed from multiple frustoconical sections. Spaces are provided on both sides of the tank to allow for expansion. The tank is integral with the vessel structure, thereby providing additional strength to the vessel.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 124,325, filed December 11, 2020, and entitled “APPARATUS FOR GAS STORAGE AND TRANSPORT,” the contents of which are incorporated herein by reference.

[0002] The present invention relates to an apparatus and method for storing and transporting fluids, namely gases and liquids such as hydrogen and natural gas, transported by ship or barge. [Background technology]

[0003] Hydrogen is becoming an important fuel for reducing carbon dioxide emissions. There are places where hydrogen can be produced at a much lower cost than where it is required. For example, Australia can produce hydrogen at a lower cost than Japan. This gap between low-cost supply and demand by water creates a need for ships that can transport hydrogen. Large-scale shipping of hydrogen by sea will be an important part of the future hydrogen ecosystem, just as shipping of natural gas by ship is a large part of the existing natural gas ecosystem.

[0004] There are known methods of transporting natural gas across bodies of water, including, for example, through subsea pipelines, by LNG carriers as liquefied natural gas, or by compressed natural gas (CNG) carriers as compressed natural gas (CNG). There are other known means, such as converting the gas to gas hydrates or diesel-like liquids (GTL) and shipping the hydrates or GTL by ship. Currently, nearly all natural gas transportation across bodies of water is done either by subsea pipelines or by LNG carriers.

[0005] Hydrogen presents several unique problems for large-scale shipping. Hydrogen is extremely light and requires either liquefaction or compression to increase its density for shipping. Liquefaction requires that hydrogen be cooled to approximately -253 degrees Celsius. This temperature is much colder than that required to liquefy natural gas, closer to absolute zero (-273°C). This cryogenic temperature requires costly liquefaction processes and costly containment systems. Hydrogen compression is well known, and most hydrogen is shipped as a compressed gas rather than liquefied. Containers for compressed hydrogen are typically either steel or composite. Steel containers are relatively less expensive than composite containers, but significantly heavier than composite containers. For road transport, the weight of the container is critical, whereas for shipping, the loss of steel weight is less critical. One of the main problems with shipping compressed hydrogen using steel is that the hydrogen molecules are small enough to fit into the steel structure, degrading the ductility of the steel over time. This process is known as embrittlement. There are established methods to prevent embrittlement, such as keeping stresses low or lining the steel with materials that are resistant to hydrogen embrittlement.

[0006] Ground transportation of compressed and liquefied hydrogen by truck is well known. There are existing hydrogen fueling stations, primarily for dedicated hydrogen-fueled commercial vehicle fleets. Large-scale transportation of hydrogen by ship is not yet established, but is an emerging industry.

[0007] One of the major obstacles to shipping compressed hydrogen by sea is the cost of a suitable hydrogen containment system suitable for transportation on a ship or barge. Thus, there is a continuing need for compressed hydrogen storage system designs that contain large amounts of hydrogen and are particularly suitable for installation on or within ships and barges, so as to reduce the overall cost of compressed hydrogen (C-H2) ships or barges. It is an object of the present invention to reduce the cost of ships or barges designed to carry compressed hydrogen and other gases.

[0008] Cost-effective hydrogen carriers would greatly improve the economic feasibility of shipping bulk compressed hydrogen by ship. Summary of the Invention [Problem to be solved by the invention]

[0009] The invention is particularly directed to the marine gas transportation of non-liquefied compressed hydrogen, but may be used to transport other gases. The invention can transport high purity gases such as natural gas, hydrogen, or combinations of liquids and gases, such as combinations of heavier hydrocarbons that are liquids and natural rich gases. The invention can also transport combinations of liquids and gases, such as combinations of oil and natural gas, for example well fluids. [Means for solving the problem]

[0010] In one embodiment, the invention of the present application embodies a large storage tank(s) housed by the hold of a ship or barge. The preferred storage system is particularly adapted for the transportation of large volumes of compressed fluids, including mixtures of gases and liquids. It is beneficial to store compressed fluids in large tanks to minimize the internal surface needed to protect against embrittlement from corrosive fluids and gaseous hydrogen. The walls of tanks used for storage of high pressure fluids must increase in thickness as the size of the tank increases. Also, large, thick-walled tanks must be supported and housed within the hull of a ship or barge. Mounting large, heavy tanks on the upper deck of a barge or ship can create stability problems, as a heavy tank mounted on the deck raises the center of gravity of the system. Thus, the invention contemplates enclosing the cargo tanks within the hull of a ship or barge. High pressure tanks are typically cylindrical in cross section, as a cylinder experiences less maximum stress than a square or rectangular shape of the same volumetric dimensions.

[0011] The maximum cylindrical tank size within a ship is constrained by the ship's dimensions. To allow the maximum tank size to be accommodated within the ship's cargo area, no cross bulkheads are required. Building such a large diameter cylinder from a single sheet of steel requires plate thicknesses that are very difficult to produce and bend into a cylindrical shape. Thus, there are two main technical problems that must be solved: 1. How to design and build a tank with fairly thick walls using unconnected thin plates 2. How to efficiently support a fairly heavy large tank or tanks within the ship structure so that expansion of the tanks due to pressurization does not damage the ship structure. This is regarding...

[0012] The invention of the present application solves each of these technical problems in a novel manner. The following description focuses on the application of ships carrying compressed hydrogen. However, the invention may also be employed to carry other gases or mixtures of gases and liquids. The tanks of the present invention may also be deployed within the holds of barges or other floating structures.

[0013] In a preferred embodiment, the cargo area of ​​the ship is divided into two elongated cargo areas separated by a double-walled longitudinal bulkhead. There are no transverse bulkheads within the cargo areas. There is one large cargo tank located in each of the two cargo holds. In an alternative embodiment, a single tank is contained within the hull defining a single hold.

[0014] The tank is constructed from several unconnected layers, for example 3 to 10 layers. In the present invention, it is not necessary to ensure 100% metal-metal contact between the layers. It is only important that the layers are in contact over the majority of the surface. The amount of contact achieved by simply laying the plates one on top of the other is sufficient to ensure that the stresses in all layers are within acceptable limits. The invention of the present application significantly simplifies the construction process and relies on plastic-elastic material properties to ensure that all layers work together to resist the stresses caused by internal pressure.

[0015] One significant additional advantage of a tank made from multiple individual layers is that even if a crack develops in one layer, the crack will not naturally propagate through adjacent layers, which greatly improves the safety of the tank compared to a similarly sized tank with a single wall thickness.

[0016] The innermost layer is designed to resist hydrogen embrittlement or corrosion caused by other gases. The material properties of this inner layer are determined by the fluid contained within the cargo tank. Subsequent layers are designed based on constructability and manufacturability. In one example, the proposed cargo is hydrogen. Thus, an exemplary first innermost layer is a stainless steel, aluminum or plastic layer capable of resisting hydrogen embrittlement. Subsequent layers may be made of high strength carbon steel.

[0017] One serious technical problem in constructing large tanks with such a series of nested lamina is that these lamina may sink under their own weight. In one embodiment, sinking of the plate is prevented by welding the outermost layer to a ship structure such as the ship's upper deck girder. This weld supports the outermost layer and prevents it from sinking. Since the upper layer does not sink, the inner layer cannot deform or sink because it is nested within the outer layer and the shape of the outer layer is restricted, i.e., it is prevented from sinking by its attachment to the upper deck.

[0018] Another technical problem is to prevent the tank from damaging the hull when it expands under pressure. To prevent this problem, a gap is left between the ship's side shell and the tank.

[0019] Another technical problem is to develop an end or head of a tank that can be easily constructed. Typically, the head of a pressure cylinder is either spherical or hemispherical. For large diameter tanks, the construction of such a head would be difficult and expensive. To overcome this problem, the end or head of the tank is constructed with a conical section, which allows the construction of the end or head using a single curved plate in several layers. This simplifies the construction and reduces the cost.

[0020] The preferred embodiment described below is a ship having a cargo hold, which is separated by a longitudinal bulkhead into a port cargo section and a starboard cargo section, each cargo section having a single tank. For smaller ships or barges, a single cargo hold may not be separated by a longitudinal bulkhead and one tank may be accommodated in the cargo hold. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic side view of a ship housing the tank. [Diagram 2] FIG. 2 is a schematic top plan view of the ship of FIG. 1 showing the tanks in line. [Diagram 3] FIG. 3 is a cross-sectional view of the vessel and tank of FIGS. 1 and 2 taken along line 3-3 of FIG. 2. [Figure 4] FIG. 2 is an enlarged side view of the front end of the tank of FIG. [Diagram 5] FIG. 5 is an enlarged side view of the wall of the tank of FIGS. 1 to 4 taken at detail 5 of FIG. 3, showing the welds in each layer. [Figure 6] FIG. 4 is an enlarged alternative cross-sectional view of FIG. 3, in which the upper layer of the tank is connected to the deck structure. [Figure 7] FIG. 4 is an enlarged alternative cross-sectional view of FIG. 3 showing the expansion spaces between each side of the tank and the ship structure. [Figure 8] FIG. 4 is an enlarged alternative cross-sectional view of FIG. 3 showing an embodiment in which the tank is supported by a ship structure separate from the deck structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Referring now to the drawings, a gas carrier vessel 10 is shown. The gas carrier vessel 10 is comprised of a vessel structure including a hull 20. The hull 20 includes a bottom shell section 22, a starboard shell section 24, and a port shell section 26. An upper deck 28 extends between the starboard shell section 24 and the port shell section 26. A forward bulkhead 30 is located within the hull 20, and an aft bulkhead 32 is located within the hull 20.

[0023] The hull 20 may be divided lengthwise by a longitudinal bulkhead 34. The longitudinal bulkhead 34 separates a port hold 36 and a starboard hold 38, which are located between the forward bulkhead 30 and the aft bulkhead 32. The starboard tank 40 is located in the starboard hold 38. The starboard tank 40 is constructed from multiple layers. In one embodiment, the starboard tank 40 is constructed from six layers, namely an outer layer 42, a second layer 44, a third layer 46, a fourth layer 48, a fifth layer 50, a sixth layer 52, and a liner layer 54 (see, for example, FIG. 5), with each of the layers 42, 44, 46, 48, 50, 52, and 54 being composed of the following sections: Other numbers of layers may be provided, for example from 3 to 10 layers.

[0024] Each of the layers 42, 44, 46, 48, 50, 52 and 54 includes a body section 40 (see, e.g., FIG. 4). Body section 60 has a forward end 62 and an aft end 64. Body section 60 is comprised of an upper semi-cylindrical portion 66 and a lower semi-cylindrical portion 68. Upper and lower semi-cylindrical portions 66, 68 are secured together by port and starboard body seam welds 70, 72.

[0025] A forward end cap 74 is secured to the forward end 62 of the body section 60. The forward end cap 74 is comprised of a frusto-conical section and a cap as follows: Other configurations, such as a dome configuration, are also possible.

[0026] 4, each of the layers 42, 44, 46, 48, 50, 52, 54 has a first frustoconical section 80 having an upper portion 82 and a lower portion 84 connected to one another via a first forward port seam weld (not visible in FIG. 4) and a first forward starboard seam weld 88. The upper portion 82 and the lower portion 84 are preferably a single curved layer of a frustum to facilitate ease of construction. The first forward frustoconical section has a forward edge 90 and an aft edge 92. The aft edge 92 is secured to the forward end 62 of the body section 60 by a first forward circumferential weld 94.

[0027] Each of the layers 42, 44, 46, 48, 50, 52, 54 defines a second forward frustoconical section 100 having an upper portion 102 and a lower portion 104 connected to one another via a second forward port seam weld 106 and a second forward starboard seam weld 108. The upper portion 102 and the lower portion 104 are preferably a single curved layer of a truncated cone to facilitate ease of construction. The second forward frustoconical section 100 has a forward edge 110 and an aft edge 112. The aft edge 112 of the second forward frustoconical section 100 is secured to the forward edge 90 of the first frustoconical section 80 via a second forward circumferential weld 114.

[0028] Each of the layers 42, 44, 46, 48, 50, 52, 54 has a third forward frustoconical section 120 having an upper portion 122 and a lower portion 124 connected to one another via a third forward port seam weld 126 and a third forward starboard seam weld 128. The upper portion 122 and the lower portion 124 are preferably a single curved layer of a truncated cone to facilitate ease of construction. The third forward frustoconical section 120 has a forward edge 130 and an aft edge 132. The aft edge 132 of the third forward frustoconical section 120 is secured to the forward edge 110 of the second frustoconical section 100 via a third forward circumferential weld 134.

[0029] Each of the layers 42 , 44 , 46 , 48 , 50 , 52 , 54 defines a front plate 140 that is secured to the forward edge 130 of the third forward frusto-conical section 120 by a fourth circumferential weld 142 .

[0030] An aft end cap (not visible in FIG. 4) is secured to the aft end 64 of the body 60. The aft end cap is preferably constructed of multiple layers of frusto-conical sections and end caps similar to the forward end cap 74 described above.

[0031] The port tank 160 is located in the port hold 36. The port tank 160 preferably has a construction similar to that of the starboard tank 40 described above.

[0032] The vessel 10 and the cargo accommodation system are sized according to ABS regulations. The accommodation system is designed based on the limit state provisions of the ABS guidelines for CNG carriers.

[0033] In one embodiment, the cargo tank 40, 160 is 20 meters in diameter and has a wall thickness of 630 mm, made up of six layers of 100 mm and one inner layer of 30 mm. Other wall thicknesses are possible depending on the design conditions, tank size and cargo. Exemplary wall thicknesses range from 20 mm to 200 mm, with overall thicknesses ranging from 200 mm to 900 mm. More specifically, the wall thickness depends on the tank size and operating conditions, but contemplated wall thicknesses for each layer are within the ranges of 20 to 200 mm, more specifically, 70 to 150 mm, and more specifically, 100 to 120 mm. Overall thicknesses range from 200 to 900 mm, more specifically, 400 to 700 mm, and more specifically, 500 to 600 mm. Other thicknesses may be necessary depending on design considerations.

[0034] Multiple cylinders nested inside each other (see detail A in FIG. 5), each having a wall thickness of, for example, about 100 mm, facilitate the ease of making cylinders with sufficient wall thickness to provide sufficient possible resistance to crack growth.

[0035] Thus, the wall is constructed from multiple layers, e.g., layers 42, 44, 46, 48, 50, 52, 54, such as six layers of X80 steel 100 mm thick, and an embrittlement resistant liner, such as stainless steel liner 54 30 mm thick. Stainless steel liner 54 is provided so that the X80 material does not become hydrogen embrittled. Other possible liner materials that resist embrittlement are possible, including aluminum and plastic. Visible in FIG. 5 are seam welds, e.g., seam weld 72 of each of layers 42, 44, 46, 48, 50, 52 and 54, designated as seam welds 72 and 72a-e shown in FIG. 5.

[0036] This nested cylindrical layer is beneficial for fracture mechanics problems because it reduces the stress at the crack tip, thereby restricting crack growth within a single cylinder, and more importantly, because there is no continuity, the crack will not jump the boundary to an adjacent layer.

[0037] For large tanks under such high pressures, the stored energy is considerable. The tank of the present invention may exhibit fatigue resistance, but ensures that even if a crack does develop, it will not be able to progress beyond the critical crack length during inspection.

[0038] Some secondary advantages of the present invention are that due to the design bending moments, the deck stresses in the ship 10 drop to about one third of what would have been the deck stresses in a comparable size tanker. This means that some steel weight reductions in the ship structure may be possible. These reductions were not possible with the original estimates of the ship's steel weight. Furthermore, the longitudinal stresses in the 20 meter tubular tanks 40, 160 (due to the design wave and still water moments) are small, as are the shear stresses.

[0039] Cargo storage design Containment design is governed by two (mainly) limit states: the service limit state (SLS) and the fatigue limit state.

[0040] If the ship 10 had a complete loading-unloading cycle every five days, over 30 years this would amount to 2,200 cycles.

[0041] The American Bureau of Shipping (ABS) requires that a factor of 10 be applied when assessing design life using the SN fatigue curve, and that the curve used must be based on a convexity of 3 standard deviations below the mean failure line (as opposed to the more typical industry standard of 2).

[0042] At 250 bar, the fatigue equation gives 24,000 cycles, which exceeds the 22,000 required.

[0043] Main ship details The main characteristics of the exemplary vessel 10 are as follows: LOA 340m Water line 325m Maximum width 48m Depth to main deck: 26m Full load draft 12.0m Deadweight draft 11.8m Full load displacement: 160,000 tons Freeboard 14.0m Cargo weight: 2,000 tonnes Cargo volume 118,000m 3 Ship Steel: 22,000 tons of EH36 steel Ship-to-cargo volume ratio 2.9:1 (average tanker is 1.5:1) GM 8.5m Rolling period: 11 seconds Ship's Inertia 4300m 4 Ship's tensile stress 330m 3 Maximum deck stress: 7 ksi (approximately 30% of allowable stress)

[0044] Exemplary Containment Designs 250 bar Yield stress: 80ksi OD: 20,000mm Wall thickness: 630mm Nominal hoop stress at 250 bar: 56 ksi Nominal safety factor against yielding: 1.4 Length: 225m(201m+12m+12m) Total pipe weight: 133,000 tonnes (127,000 tons of 80ksi steel plus 6000 tons of stainless steel)

[0045] Example calculation of allowable pressure The allowable SLS design pressure for safety class high according to DNV Subsea Pipeline Systems Rule OS-F101 clause D400 is obtained from the following, where the MAOP is 95% of this value:

[0046] The formula for allowable design pressure for the serviceability (yield) limit state is: Design pressure = 2 x t min ÷(OD-t min )×α u ×f y ×2÷3 0.5 ÷γ sc ÷γ m where: t min = minimum wall thickness of the pipe at any point, OD=outer diameter f y = Minimum number of specified yield stresses α u = Material strength factor equal to or 0.96 Gamma sc = Safety class safety factor. In this highest class case, the safety class safety factor is 1.308. Gamma m = equal to the material safety factor.

[0047] Putting the numerical values ​​into the above formula gives: 250 bar Design pressure = 2 x 24.8 ÷ (787.4-24.8) x 80,000 x 0.96 x 2 ÷ 1.732 ÷ 1.308 ÷ 1.15 = 3835 psi. (264 bar) Multiplying by 0.95 gives an MAOP of 3642 psi (251 bar)

[0048] Example Fatigue Assessment ABS guidelines indicate the use of a factor of 10 when assessing design life with the appropriate SN curve, which is conservatively based on 3 standard deviations below the mean failure line (as opposed to the more usual industry standard of 2).

[0049] The relationship between the number of cycles and the stress range is: Log(N) = Log(C) - cδ - mLog(F sr ) where: N = stress range F sr Predicted number of cycles to failure under C = a constant related to the average SN curve of the weld m = the inverse slope of the mean SN curve c = number of standard deviations below the mean δ=Standard deviation of Log(N)

[0050] Inserting numerical values ​​into this formula gives us: 250 bar class C weld Log 10 (N)=14.034-3×0.204-3.5Log(384)=4.377

[0051] From this formula, N is 10 4.377 = 24,000 cycles.

[0052] In one embodiment, the damage stability requirements are primarily met by the inward continuation of portions of the watertight bulkheads 30, 32 in the outer double hull side skin, which provide a watertight seal with the bodies 40 and / or 160.

[0053] In one embodiment, compartmentalization within the storage tank 40, 160 is achieved by introducing partitions into the elongated cylinder, where necessary.

[0054] In one embodiment, the nested tank is constructed by first placing the outer lower circular section, e.g., 68 of layer 42 (see, e.g., FIG. 4), and welding it to the upper structure. Then, the nesting of the lower semicircular portions of layers 44, 46, 48, 50, 52, and 54 is installed under gravity. Preferably, there are no welded connections between the skins. Then, the top inner semicircular section, e.g., 66, is lowered to the bottom inner section, e.g., 44, 46, 48, 50, 52, and 54, and the inner seam welds, e.g., 70, 72, are completed from both sides. This welding is then continued on one side welds until the outer upper section 66 is seam welded onto its counterpart via seam welds 70, 72. See FIG. 5, Detail A above.

[0055] The length of each section depends on the crane capacity of the yard. A 50 meter section weighs approximately 1400 tonnes. The 100 mm thick half cylinder with extremely high D / t ratio allows easy alignment for seam welding by various combinations of ballasting shears, hydraulic and temperature measures. The end caps 74, 144 are specifically designed with a single bend to aid in forming and assembly.

[0056] Moss tanks for LNG require equatorial ring support. The reason for this is that the internal design pressure is fairly low and the resulting shell cannot support itself from below. However, in one embodiment, Applicant's tanks 40, 160 are cylindrical, for example at 250 bar, and have an operating pressure of about 500 times or more that of a Moss tank, making them easier to support from below. This support also acts as a shear force transfer mechanism to transfer bending moments to the ship structure, such as the ship's deck 28 and bottom shell. Moss tanks are typically not integrated with the ship 10. Applicant's tanks 40, 160 are fully integrated and are the stiffest and strongest part of the ship structure. By welding the top and bottom of the tanks 40, 160 to the ship structure, such as the deck structure, the tanks 40, 160 become the primary structural element of the ship, thereby adding strength to the ship. Perhaps the best analogy is a World War II submarine, where the upper deck is attached as an appendage rather than a load-bearing member. The primary support for the tanks 40, 160 comes from both the horizontal and longitudinal girders. Lateral support is from the transverse girders and the watertight bulkheads 30, 32 mentioned above. The longitudinal girders (top and bottom) are also used as shear transfer connections to the deck 28 and the tank skin.

[0057] As shown in Figure 6, the outer layer 42 of the tank 40 may be connected to the deck 28, for example by welding to the support 39. The support 39 is shown in Figures 6 and 7 as part of the ship structure of the deck 28. However, the support 39 may be provided to support the tank 40 as a separate ship structure from the deck 28 (see, for example, Figure 8). Subsidence of the layers 42, 44, 46, 48, 50, 52 and 54 is prevented by welding the outermost layer 42 to the support 39 or to girders of the upper deck 28 of the ship 10. The connection to the deck 28 supports the outermost layer 42 and prevents it from subsiding. Since the upper layer 42 does not subside, the inner layers 44, 46, 48, 50, 52 and 54 do not deform or subside. 1 because the inner layers 44 , 46 , 48 , 50 , 52 and 54 are nested within the outer layer 42 whose shape is restricted by its attachment to the upper deck 28 .

[0058] 7, expansion spaces 43 and 45 may be provided between the tank 60 and the structural skin portion 24 of the hull 20, and between the tank 40 and the longitudinal bulkhead 34, respectively. The expansion gaps or spaces 43 and 45 prevent the tank 60 from damaging the hull 20 as the tank 40 expands during pressurization.

[0059] Preferably, the nested tanks are not connected to each other in any way. They are tubes inside tubes. If the nested tanks had no ends and were fully constructed, they would slide out. Imagine nested tubes stretching end to end as beams under their own weight, resulting in a simple bending moment. The stress and deflection are based on the inertia of the tubes. If the tubes are close together and there are no gaps, the overall inertia of the tubes is exactly the same as if the tubes were solid. This nested tube is completely different from having multiple layers of plates stacked on top of each other. The inertia of a nested tube is calculated as follows: Inertia=π / 64(D 1 4 -D 2 4 +D 2 4 -D 3 4 +D 3 4 .........)=π / 64(204-18.744)=1800m 4

[0060] For two tanks, the inertia is 3600m 4 The total inertia of the hull and cylinder acting together is 4300m 4 So about 80% of the ship's stiffness comes from the cargo tanks 40-160.

[0061] Thus, the present invention is well adapted to carry out the objects and attain the aims and advantages mentioned above, as well as those inherent therein. Although preferred embodiments of the present invention have been described for the purposes of this disclosure, numerous changes and modifications will become apparent to those skilled in the art. Such changes and modifications are encompassed within the spirit and scope of the present invention as defined by the appended claims.

[0062] It is to be understood that the terms "comprise", "comprise", "consist" and grammatical variations thereof do not exclude the addition of one or more elements, features, steps or integers or groups of such, but rather these terms are to be interpreted as designations of elements, features, steps or integers.

[0063] When the specification and claims refer to "a further" element, this does not exclude there being two or more of the further element.

[0064] When a claim or specification refers to "a" or "an" element, it should be understood that such a reference is not intended to be construed as referring to only that element.

[0065] When the specification states that a certain component, feature, structure or characteristic "may," "might," "can" or "could" be included, it should be understood that the particular component, feature, structure or characteristic is not required to be included.

[0066] Methods of the present invention may be implemented by performing or completing selected steps or tasks manually, automatically, or a combination thereof.

[0067] The term "method" can refer to manners, means, techniques, and procedures for accomplishing a given task, including but not limited to manners, means, techniques, and procedures that are known to those of ordinary skill in the art or that are readily developed from known manners, means, techniques, and procedures by those of ordinary skill in the art.

[0068] The term "at least" followed by a number is used herein to denote the beginning of a range beginning with that number (which may be a range with an upper limit or an open-ended limit, depending on the variable being defined). For example, "at least 1" means 1 or more than 1. The term "at most" followed by a number is used herein to denote the end of a range ending with that number (which may be a range with a lower limit of 1 or 0 or an open-ended limit, depending on the variable being defined). For example, "at most 4" means 4 or less than 4, and "at most 40%" means 40% or less than 40%.

[0069] In this document, when a range is given as "from (first number) to (second number)" or "from (first number) to (second number)", this means a range whose lower limit is the first number and whose upper limit is the second number. For example, 25 to 100 should be interpreted as meaning a range whose lower limit is 25 and whose upper limit is 100. Furthermore, when a range is given, it is noted that all possible subranges or intervals within that range are also specifically contemplated, unless the context dictates otherwise. For example, when the specification gives a range of 25 to 100, such a range is also intended to include subranges such as 26 to 100, 27 to 100, etc., 25 to 99, 25 to 98, etc., as well as all other possible combinations of lower and upper values ​​within the stated range, for example, 33 to 47, 60 to 97, 41 to 45, 28 to 96, etc. It is noted that integer range values ​​are used in this paragraph for illustrative purposes only. It should be understood that decimal and fractional values ​​(eg, 46.7 to 91.3) are also contemplated as possible subrange endpoints unless expressly excluded.

[0070] It should be noted that when reference is made in this specification to a method including two or more specified steps, the specified steps may be performed in any order, or simultaneously (unless the context excludes this possibility), and the method may also include one or more other steps performed before any of the specified steps, between two specified steps, or after all specified steps (unless the context excludes this possibility).

[0071] Further, it should be noted that approximation terms (e.g., "about," "substantially," "approximately," etc.) should be interpreted according to their ordinary and customary meaning as used in the relevant art, unless otherwise specified herein. In the absence of a specific definition within this disclosure and ordinary and customary usage in the relevant art, such terms should be interpreted as plus or minus 10% of the base value.

[0072] The present invention is thus well adapted to carry out the objects and attain the aims and advantages mentioned above, as well as those inherent therein. Although the device of the present invention has been described and illustrated herein with reference to certain preferred embodiments in connection with the drawings accompanying this specification, various changes and further modifications, aside from what is shown or suggested herein, may be made by those skilled in the art without departing from the spirit of the inventive concepts, the scope of which is determined by the following claims.

Claims

1. A fluid transport vessel, comprising: The ship, a tank longitudinally received within the hull, the tank having a plurality of layers, the plurality of layers including an outer layer; a ship structure above said tank; wherein the outer layer of the tank is supported by the ship structure.

2. The fluid transport vessel of claim 1 , wherein the vessel structure supports a deck.

3. a forward bulkhead within the hull; an aft bulkhead within said hull; 2. The fluid transport vessel of claim 1, further comprising: a tank disposed between the forward bulkhead and the aft bulkhead.

4. a longitudinal bulkhead within the hull, the longitudinal bulkhead separating the hull into a port hold and a starboard hold; a second tank in one of the port hold and the starboard hold; and 2. The fluid transport vessel of claim 1, further comprising: a first tank and a second tank, the first tank being in one of the port and starboard holds not occupied by the second tank.

5. The fluid transport vessel of claim 1 , wherein the plurality of layers comprises between 3 and 10 layers inclusive.

6. The plurality of layers further comprises an inner layer; The fluid transport vessel of claim 1 , wherein the inner layer is constructed from a material that is resistant to embrittlement.

7. The plurality of layers comprises an inner layer; The fluid transport vessel of claim 1 , wherein the inner layer is constructed from a material that is resistant to corrosion.

8. 2. The fluid transport vessel of claim 1, wherein the plurality of layers further comprises an inner layer and an intermediate layer between the inner layer and the outer layer, the intermediate layer providing additional strength to the tank.

9. each layer of the plurality of layers having a forward end cap and an aft end cap; The fluid carrying vessel of claim 1 , wherein the forward end cap and the aft end cap of each of the layers are constructed from a plurality of frusto-conical sections.

10. The fluid transport vessel of claim 9 , wherein the frusto-conical section defines a single curvature.

11. at least one layer of the plurality of layers has a body section having a forward end, an aft end, an upper semi-cylindrical section, and a lower semi-cylindrical section, the upper semi-cylindrical section and the lower semi-cylindrical section secured together with a port body seam weld and a starboard body seam weld; a forward end cap adjacent the forward end of the body section; The fluid carrying vessel of claim 1 , wherein an aft end cap is adjacent the aft end of the body section.

12. the outer layer of the tank has a top, a bottom, a port side, and a starboard side; the upper portion of the tank contacts a ship structure; the bottom of the tank contacts a ship structure; 2. The fluid transport vessel of claim 1, wherein a space is provided between said port side and said ship structure and between said starboard side and said ship structure to accommodate expansion of said tanks.

13. The fluid transport vessel of claim 1 , wherein each of said layers of tanks is not connected to an adjacent layer of tanks.

14. A fluid transport vessel, the fluid transport vessel comprising: The ship, a tank longitudinally received within the hull, the tank having a plurality of layers, the plurality of layers including an outer layer; and wherein each layer of the plurality of layers of tanks has an end cap constructed from a plurality of frusto-conical sections.

15. the vessel includes a structure above the tank; The fluid transport vessel of claim 14 , wherein the outer layer of the tank is supported by the structure.

16. The fluid transport vessel of claim 15 , wherein the structure supports a deck.

17. a forward bulkhead within the hull; an aft bulkhead within the hull; 15. The fluid transport vessel of claim 14, further comprising: said tank being between said forward bulkhead and said aft bulkhead.

18. a longitudinal bulkhead within the hull, the longitudinal bulkhead separating the hull into a port hold and a starboard hold; a second tank in one of the port hold and the starboard hold; and 15. The fluid transport vessel of claim 14, further comprising: said tank in one of said port and starboard holds not occupied by said second tank.

19. 15. The fluid transport vessel of claim 14, wherein the plurality of layers comprises between 3 and 10 layers inclusive.

20. The plurality of layers further comprises an inner layer; 15. The fluid transport vessel of claim 14, wherein the inner layer is constructed from a material that is resistant to embrittlement.

21. The plurality of layers further comprises an inner layer; 15. The fluid transport vessel of claim 14, wherein the inner layer is constructed from a material that is resistant to corrosion.

22. 15. The fluid transport vessel of claim 14, wherein the plurality of layers further comprises an inner layer and an intermediate layer between the inner layer and the outer layer, the intermediate layer providing additional strength to the tank.

23. The fluid transport vessel of claim 14 , wherein the frusto-conical section defines a single curvature.

24. at least one layer of the plurality of layers has a body section having a forward end, an aft end, an upper semi-cylindrical section, and a lower semi-cylindrical section, the upper semi-cylindrical section and the lower semi-cylindrical section secured together with a port body seam weld and a starboard body seam weld; a forward end cap adjacent the forward end of the body section; The fluid carrying vessel of claim 14 , wherein an aft end cap is adjacent the aft end of the body section.

25. the outer layer of the tank has a top, a bottom, a port side, and a starboard side; the upper portion of the outer layer contacts a ship structure; the bottom of the outer layer contacts a ship structure; 15. The fluid transport vessel of claim 14, wherein a space is provided between the port side and the ship structure and between the starboard side and the ship structure to accommodate expansion of the tank.

26. 15. The fluid transport vessel of claim 14, wherein each of said layers of tanks is not connected to an adjacent layer of tanks.

27. 1. A method of constructing multiple layers of tanks within a ship's hull, the method comprising the steps of: placing a semi-cylindrical outer lower section within the hull and fastening the outer lower section to the hull; placing one or more semi-cylindrical sub-sections within the outer sub-section, the semi-cylindrical sub-sections comprising an inner sub-section; placing a semi-cylindrical inner upper section on the inner lower section and welding the inner upper section to the inner lower section on both sides to form an inner cylinder; placing one or more semi-cylindrical upper sections and mating them with their counterparts on the semi-cylindrical lower section and welding each mating pair on both sides to form a plurality of nested cylinders; installing an end cap on each of the plurality of nested cylinders to form a plurality of nested tanks; A method comprising:

28. 1. A method of stiffening a fluid carrying vessel, the method comprising: placing a multi-layer tank longitudinally within a hull of a ship, the multi-layer tank having an outer layer having a top and a bottom; fastening the bottom of the outer layer to a ship structure below the multiple layers of tanks; fastening said upper portion of said outer layer to a ship structure above said plurality of layers of tanks; wherein the fastening step integrates the multiple layers of tanks with the ship structure, allowing the multiple layers of tanks to become a structural element of the ship, thereby adding strength to the ship.

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