NO348169B1

NO348169B1 - Four‐lobe cargo tank for transporting and / or storage of liquified gases and a method of transporting gas

Info

Publication number: NO348169B1
Application number: NO20221199A
Authority: NO
Inventors: Henrik Fleischer; Knut Erik Børseth; Nils Christian Høy-Petersen
Original assignee: Karbon Ccs Global Ltd
Priority date: 2022-11-09
Filing date: 2022-11-09
Publication date: 2024-09-16
Also published as: NO20221199A1

Description

TITLE: Four‐lobe cargo tank for transporting and / or storage of liquified gases and a method of transporting gas.

Field and background of the invention

The present invention relates to the field of transporting and / or storage of liquified gases in a tank, more specifically in a four-lobe cargo tank. Pipelines may provide a possible transport for short runs, but the for long distances the capital cost will be prohibitively high, so an alternative transport of captured CO2 from an initial source to a facility of usage or long-term isolation of captured CO2 is needed.

The applicant has been working with development of carbon capture systems for decades and within this field there are missing facilitties for storage and transportation of the captured Carbon Dioxide (CO2). To transport the captured CO2 in an efficient and economical manner initiated the present invention. As an example, Carbon capture plants may be located in South Korea and recipients for using CO2 for enhanced oil recovery (EOR) may be located in USA and / or Persian Gulf. An efficient and economical trade for such a long haul advantageously also includes cross trades to utilize the cargo transport capacity in both directions. An efficient cross trade can be to ship the CO2 from South Korea to USA and / or Persian Gulf and return with e.g. liquid natural gas (LNG).

Prior art

European patent application, EP3318791 A1, describes a multi-lobe tank for containing liquefied gas, for mounting into a hull of a vessel. The tank comprises at least a first longitudinally extending multi-lobe tank part having a center line A and a second longitudinally extending multi-lobe tank part having a center line B that are positioned one behind the other resulting in a forward multi-lobe tank part and a rear multi-lobe tank part with aligned center lines A, B. More specifically the patent application claims a multi-lobe tank for containing pressurized liquids, such as liquefied gas, for mounting into a ships hull, wherein the tank comprises at least a first longitudinally extending multi-lobe tank part having a center line and a second longitudinally extending multi-lobe tank part having a center line that are positioned one behind the other resulting in a forward multi-lobe tank part and a rear multi-lobe tank part with aligned center lines, wherein the first part is tapered towards an end of the first part. The invention in EP3318791 A1 is initiated to reduce the gravity center of said multi-lobe tank and therefor increase the stability of the vessel, a three-lobe cargo tank with two lobes at the tank top and one on the top of those two is therefor a preferred embodiment for that invention.

Another patent application, US2021348719 A1, describes a storage tank having a generally cubic configuration. The storage tank includes four vertically oriented cylindrical walls positioned approximately 90 degrees apart from one another and an outer support structure is coupled to the outer surface of the storage tank. The tank has an internal bulkhead structure between the four vertical cylinders where a membrane inner portion is configured to partially obstruct a flow of liquid.

In a French patent, FR1037900A, it is described a pressure tank capable of containing both a liquid and a gas and it relates more particularly to a closed container consisting of compartments of cylindrical shape assembled together and provided with closures at their ends. The container or the tank object applies particularly to the conservation of volatile liquids such as gasoline, butane gas and / or propane, tank in which it is desired to avoid losses by evaporation by keeping the gas under pressure above the liquid level.

The present invention is generally concerned with solving one problem related to the prior art.

Brief summary of the invention

The invention is defined by the attached independent claim 1 which is a four‐lobe cargo tank for transporting and/or storage of liquified gases, wherein the tank comprises four main lobes each with a cylinder sector outer shell and main lobe axis, said four main lobes arranged with said four main lobe axis axial‐parallel with and about a common main central axis, said four main lobes joined by four web frames with four corresponding diagonally arranged perforated bulkheads directed outwardly from said main central axis, said tank further comprises first and second end covers each end cover comprising four quarter spherical shell portions each forming an end portion of said cylinder sector outer shell, said quarter spherical shell portions of said first and second end covers respectively, joined and closing toward said main central axis by first and second four diagonally arranged cylindrical 45-degree cut pipe ‐portions each arranged with its axis transverse to said main axis.

In an embodiment of the present invention it also relates to a method of transporting gas, comprising a vessel, liquefied gas carrier, with at least one four-lobe cargo tank, for loading liquefied natural gas (LNG) under cryogenic conditions to said one or more four-lobe tanks at an LNG loading terminal, and sailing said vessel, liquefied gas carrier, to an LNG unloading terminal for unloading said liquefied natural gas (LNG) at said unloading terminal for consumption and if necessary, sailing said vessel, liquefied gas carrier, to a loading terminal for liquefied carbon Dioxide (CO2) for loading captured liquefied Carbon Dioxide (CO2) into said one or more four-lobe tanks, for then sailing said captured liquefied Carbon Dioxide (CO2) to a liquefied Carbon Dioxide (CO2) unloading terminal,

- for permanent storage,

- or for industrial consumption.

An advantage of this embodiment solves problems related to transport of combined cargo e.g. high density pressurized cargo during one voyage and cryogenic temperature performance down to liquefied natural gas on the return voyage, increasing the efficiency of the vessel, liquefied gas carrier, and indirectly reduces the costs.

Further inventive embodiments of the invention are set out in the dependent claims.

Figure descriptions

Embodiments of the present invention will now be described, by way of example only, with reference to the following figures, wherein:

Figure 1a shows in a isometric view an embodiment of the four-lobe cargo tank 1, with its four main lobes 11, as seen towards its second end cover 13b to make the common main central axis a1 and mail lobe axis' a11 more apparent. As illustrated in the Figure the common main central axis a1 is in the center of the four-lobe cargo tank 1. The Figure further shows that the main lobe axes a11 in the cylinder-sector center of each of the main lobes 11, respectively. Each of the four lobes 11 has its own main lobe axis a11.

Figure 1b shows an embodiment of the four-lobe cargo tank 1, with its four main lobes 11, in an isometric view as seen towards its first end cover 13a, which is the top end cover 13a in an upright configuration of the common main central axis a1. Figure 1b shows the cylinder sector outer shell 12 of each main lobes 11, which holds a form like a half part of a cylindrical tube and extend from the first end cover 13a to the second end cover 13b. Figure 1b shows the first end cover 13a comprising:

- four of quarter-spherical shell portions 14a

- four of cylindrical 45-degree cut pipe portions 15a

- a central common pipe 20.

Figure 1c shows an end view of an embodiment of second end cover 13b of the fourlobe cargo tank 1. Figure 1c shows the second end cover 13b comprising:

- four of quarter spherical shell portions 14b

- four of cylindrical 45-degree cut pipe portions 15b

- a central common pipe 20.

Figure 2a shows in an end view an embodiment of the first end cover 13a of the fourlobe cargo tank 1. Figure 2a shows a diagonally extending transverse axis a15 between two of the four cylindrical 45-degree cut pipe portion 15a, indicated by a dotted line K-K. Said transverse axis a15 is a diagonal centerline across the first and also the second end cover 13a, 13b between those two mutually facing cylindrical 45-degree cut pipe portions. Figure 2a also show a centerline, marked N-N, that divides the four main-lobe cargo tank 1 said first end cover 13a into two halves.

Figure 2b shows a combined elevation and section view of an embodiment of the four-lobe cargo tank 1 cross-section at said centerline N-N, as indicated in Figure 2a, wherein the internal structure, such as perforated bulkheads 16 and web frames 17 are shown, including the central pipe 20. As shown in the Figure, said web frame 17 extends between a first and a second end portion of said central pipe 20, and said perforated bulkhead 16 is arranged enveloped in the area between said web frame 17 and said central pipe 20 as shown. Another embodiment [not shown] is to arrange the perforated bulkheads 16 between said web frames 17 and are join them together at the common main central axis a1 wihtout any central pipe 20.

Figure 2c shows in a combined elevation and section view an embodiment of a cross-section of the four-lobe cargo tank 1 at said dotted line K-K, as indicated in Figure 2a, wherein one of said transverse axes a15 of said second end cover 13b, is indicated with an inclining angle α, from a baseline which is orthogonal to said common main central axis a1. The Figure further shows said first and second end covers 13a, 13b comprising their quarter spherical shell portions 14a, 14b and cylindrical 45-degree cut pipe portions 15a,15b. A cross-section of said central pipe 20 is also shown in the Figure.

Figure 2d shows a combined isometric view and diagonal cross section of an embodiment of the same cross-section as in Figure 2b of the four-lobe cargo tank 1, for providing an overview of the internal space of the four-lobe cargo tank 1 and its internal structures comprising a perforated bulkhead 16 and a web frame 17 and a cross-section of the central pipe 20.

Figure 3a shows an elevation side view of the four-lobe cargo tank 1 comprising main lobes 11 arranged with reinforcing ribs 18. The Figure further shows that the web frames 17 partly protrude between said main lobes 11 near said central pipe 20 at said first and second end covers 13a, 13b and join the main lobes 11 cylindrical 45-degree cut pipe portions 15a,15b which further join said quarter spherical shell portions 14a, 14b. Figure 3a shows an embodiment wherein said reinforcing ribs extends about said cylinder sector outer shells 12. A dotted an axis-transverse line, marked L-L, is marked across a portion (which may in an embodiment be an upper portion) of the Figure, as a mark for where the cross-section plane in the isometric section view in next Figure, Figure 3b is taken.

Figure 3b shows an isometric view and and part section along the plane as marked by the line L-L in Figure 3a. Figure 3b shows an embodiment of the four-lobe cargo tank 1 cross-section L-L, in an isometric view , such that part of the internal structure of all four main lobes 11 are shown. Figure 3b also shows a dotted circle marked M, indicating a portion of the drawing which is enlarged to show in more detail in Figure 3c.

Figure 3c shows the enlarged details from said dotted circle marked M from Figure 3b. The Figure shows an embodiment of the four-lobe tank comprising an arrangement on assembly of said web frame 17 joining between two adjacent of said cylinder sector outer shells 12 and an arrangement for said web frame 17 and said reinforcing rib 18 (which is below the plane L-L). The Figure also shows an arrangement for said web frame 17 and said perforated bulkhead 16.

Figure 4a shows an arrangement of said four-lobe cargo tanks 1 arranged as cargo tanks shown placed in a transverse section of a vessel hull 2, such as a hull of a ship, wherein said four-lobe cargo tanks 1 are arranged with each their common main central axis a1 in a vertical position [Vertical position, as in said main central axis a1 is mainly perpendicular on said vessel hulls tank top]. Figure 4a shows an embodiment comprising two four-lobe cargo tanks 1 arranged side-by-side in said vessel hulls 2 breadth. Figure 4 also shows a dotted line marked P-P, which indicates a plane of a cross-section view shown in Figure 4b.

Figure 4b shows in a top view an embodiment of the four-lobe cargo tanks 1, arranged as cargo tanks in a plane section P-P of the vessel hull 2 above. The Figure shows a plane section of a vessel hull 2 comprising the top view of two four-lobe cargo tanks 1 arranged port and starboard side by side other and in rows of three, a total number of six four four-lobe cargo tanks.

Figures 5a and 5b show another view of the embodiments shown in Figures 4a and 4b.

Figures 6a, 6b and 6c, show an embodiment of the four-lobe cargo tanks 1 arranged as cargo tanks onboard a vessel 0. Figure 6a shows the vessel 0 section in center line, comprising vertically installed four-lobe cargo tanks 1 on vessel tank top 3.

Figure 6b shows an embodiment wherein an upper deck is arranged above the fourlobe cargo tanks 1. Figure 6c shows a midship section view of said vessel 0 comprising two four-lobe cargo tanks 1 arranged with vertical-common main central axis a1 within the vessel hull 2.

Figure 7a shows an embodiment of the invention wherein said four-lobe cargo tanks 1 are installed onboard a vessel 0. Figure 7a shows a plane view at main deck comprising four-lobe cargo tanks 1 that are arranged then in two rows in the breadth onboard said vessel 0. Figure 7b shows an embodiment of said vessel 0 in a section below tank top.

Figure 8a shows an embodiment of the invention wherein four-lobe cargo tanks 1 are arranged onboard a vessel 0 with combi cargo tanks 4, 1, 30, from a center line section view. Said vessel 0 with combi cargo tanks 4 comprises both said four-lobe cargo tanks 1 and further comprises cryogenic cargo tanks 30 such as LNG-tanks. Figures 8a and 8b show an embodiment wherein said four-lobe cargo tanks 1 are horizontally arranged onboard said vessel 0, horizontally arranged in the meaning that said common main central axis a1 is mainly parallel with the combi cargo tank vessel tank top 6, and with combi cargo tanks 4, 1, 30, .

Figure 8b shows an embodiment of the invention wherein said four-lobe cargo tanks 1 and said cryogenic cargo tanks 30 installation onboard said vessel 0 with combi cargo tanks 4, 1, 30. Figure 8b shows a plane view at main deck comprising ten fourlobe cargo tanks 1 and five cryogenic cargo tanks 30 that are arranged seven in a row and two in the breadth, and one fore cryogenic cargo tank 30 in forward portion of said vessel 0 with combi cargo tanks 4, 1, 30.

Figure 9a shows a cross-section view of of a vessel 0 with combi cargo tanks 4 with axial 20-transverse sections through two four-lobe cargo tanks 1 arranged onboard said vessel 0 with combi cargo tanks 4. The Figure shows longitudinally oriented horizontally installed four-lobe cargo tanks 1 on said combi cargo tank vessel tank top 6 in said combi cargo tank vessel hull 5.

Figure 9b shows a cross-section view of said vessel 0 with combi cargo tanks 4 with a cross-section view of vertical-axis embodiments of two cryogenic cargo tanks 30 arranged onboard said vessel 0 with combi cargo tanks 4, 1, 30.

Embodiments of the invention

The present invention provides a four‐lobe cargo tank 1 for transporting and/or storage of liquified gases,

wherein the tank 1 comprises four main lobes 11 each with a cylinder sector outer shell 12 and main lobe axis a11,

‐ said four main lobes 11 arranged with said four main lobe axis a11 axial‐parallel with and about a common main central axis a1,

‐ said four main lobes 11 joined by four web frames 17 with four corresponding diagonally arranged perforated bulkheads 16 directed outwardly from said main central axis a1,

‐ said tank 1 further comprises first and second end covers 13a, 13b each end cover 13a, 13b comprising four quarter spherical shell portions 14a, 14b each forming an end portion of said cylinder sector outer shell 12,

‐ said quarter spherical shell portions 14a, 14b of said first and second end covers 13a, 13b respectively, joined and closing toward said main central axis a1 by first and second four diagonally arranged cylindrical 45‐degree cut pipe portions 15a, 15b each arranged with its axis a15 transverse to said main axis a1.

The invention provides a four-lobe cargo tank 1 for transporting liquified CO2 to e.g. enhanced oil recovery sequestration, based on CO2 gas injection, one way, and which in a further embodiment is arranged to return with other kinds of liquified or pressurized gas, such as LNG, LPG or Ammonia. Due to the utilization of the tank for transport of gases in both directions the trade will be lucrative, both economically and environmentally, as the cargo tanks can be utilized both ways and the returning voyage is profitable over an empty return.

An advantage with the four-lobe tank 1 is that the structural features of four main lobes 11 increases the overall strength qualities' over a regular cylindrical tank. The four-lobe tank 1 with same cargo conditions, as pressure, will have an about four times increased volume over a regular cylindrical tank with same shell thickness. This is a benefit as the four-lobe tank 1 can hold more cargo with same design criteria’s than an individual regular cylindrical tank, thus take up less space onboard a vessel. In other words, the footprint of the four-lobe tank 1, when installed with vertical axis, is only 66% of the footprint of four individual cylindrical tanks of equal radii as the lobes 11 radii.

An other advantage with the four-lobe tank 1, is that the internal structure joined by four web frames 17 with four corresponding diagonally arranged perforated bulkheads 16 directed outwardly from said main central axis a1, increases the strength with regard to holding cargo with relatively high density during transport, such as holding as liquefied CO2.

In an embodiment of the invention the four‐lobe cargo tank 1 further comprises a central pipe 20 that is arranged co‐axial with said main central axis a1, wherein

‐ said central pipe 20 joining said first and second four diagonally arranged cylindrical 45‐degree cut pipe portions 15a, 15b, respectively, and said four web frames 17, near either end portions of said central pipe 20,

‐ said four perforated bulkheads 16 extending radially out from said central pipe 20. In other words, the four perforated bulkheads are joined by said central pipe 20.

The reason behind this arrangement is to arrange cargo pipes for loading and unloading said four-lobe cargo tank 1 with liquified gases through said central pipe 20. Another benefit is that cables, such as for instrumentation and power, can also be run through said central pipe 20, and when said four-lobe cargo tanks 1 are built in large scale, then even passages for manual human inspection and manholes into to the main lobes 11 can be arranged through the central pipe 20. Another benefit is that the weld joint between the four diagonally arranged perforated bulkheads 16 and the four web frames 17 can be connected at said central pipe 20, the same applies for the said central pipe 20 joining said first and second four diagonally arranged cylindrical 45‐degree cut pipe portions 15a, 15b which can be welded towards the central pipe 20.

In an embodiment of the invention, wherein said four-lobe cargo tank 1, further comprises at least one circumferential reinforcing ring stiffener 18 to reinforce said cylinder sector outer shell 12. Said circumferential reinforcing ring stiffener 18 prevents buckling on said outer shell 12. Another benefit is that said four-lobe cargo tank 1 can resist higher internal pressure with out increasing thicknesses of said cylinder sector outer shell. Such reinforcing ring stiffeners 18 can also be used as structural support for the arrangement onboard a vessel 0. Said reinforcing ring stiffener(s) 18 can be arranged on the outside of said four-lobe cargo tank 1 [as shown on Figures 3a-3c], or on the inside of said four-lobe cargo tank 1. If said reinforcing ring stiffener 18 is arranged on the inside of said four-lobe cargo tank 1, said reinforcing ring stiffener 18 becomes a part of the internal structure of said fourlobe cargo tank 1.

In an embodiment of the invention, each said second four diagonally arranged cylindrical 45‐degree cut pipe portions 15b with its transversely arranged axis a15 is inclined toward the corresponding end portion of said central common pipe 20.

Such an arrangement in order to enable liquid draining of the tank towards and into a drain in the central common pipe 20 when installed in a vertical position. In an embodiment of the invention the inclination angle α is 5 degrees.

In an embodiment of the invention said liquefied gases comprise liquefied carbon dioxide.

In an another embodiment of the invention, said liquefied gases comprise liquefied natural gas, liquefied ammonia, or compressed natural gas.

In an embodiment of the invention the four-lobe cargo tank 1 is a pressure vessel for pressure up to 12 barg [bar=bar gauge]. In another embodiment of the invention the four-lobe cargo tank 1 is a pressure vessel for pressure up to 8 barg. In another embodiment of the invention the four-lobe cargo tank 1 is a pressure vessel for pressure above 5,2 barg.

In a further embodiment of the invention said pressure vessel is also cryogenic arranged for holding liquefied Carbon Dioxide (CO2).

In a further embodiment of the invention said pressure vessel is also arranged for holding liquefied natural gas (LNG) at ambient pressure.

In an embodiment of the invention the four-lobe cargo tank 1 is arranged to be installed onboard a vessel liquefied gas carrier 0.

In an embodiment of the invention the four-lobe cargo tank 1 is arranged to be installed with cryogenic cargo tanks 30 onboard a vessel 0 with combi cargo tanks 4.

In an embodiment of the invention, wherein said web frames 17 protrude out between said four main lobes 11, so that said web frames 17 also serve as flanges for connection said four main lobes 11 and reinforce said four-lobe cargo tank 1. This will reinforce the structure of the cargo tank 1 and is useful especially when the cargo tank serve as a pressure vessel.

In an embodiment of the invention said four-lobe cargo tank 1 construction materials have qualification with enhanced mechanical properties for low temperature service.

In an embodiment of the invention said central pipe 20 protrude beyond each end covers 13a, 13b. In a further embodiment of the invention said central pipe 20 protrusions are arranged as main bearing points of said four-lobe cargo tank 1.

In an embodiment of the invention said central pipe 20 protrude from the first and/or second end cover(s) 13a, 13b and said central pipe 20 protrusion(s) is/are arranged as lifting point(s) of said four-lobe cargo tank 1.

In an embodiment of the invention said four-lobe cargo tank 1 material is low temperature steel, such as carbon manganese steel, nickel steel, stainless steel.

In an embodiment of the invention said four-lobe cargo tank 1 material comprises cryogenic materials, such as nickel steel e.g.9% Ni, stainless steel, high manganese steel e.g. NV-Mn400.

In an embodiment of the invention said four-lobe tank 1 material is a combination of low temperature steel and cryogenic materials.

In an embodiment of the invention, related to a method of transporting gas, comprising

- using a vessel, liquefied gas carrier 0 according to the above,,

- loading liquefied natural gas LNG under cryogenic conditions to said one or more four-lobe tanks 1 at an LNG loading terminal,

- sailing said vessel, liquefied gas carrier 0 to an LNG unloading terminal,

- unloading said liquefied natural gas (LNG) at said unloading terminal for consumption,

- if necessary, sailing said vessel, liquefied gas carrier 0 to a loading terminal for liquefied carbon Dioxide (CO2)

- loading captured liquefied Carbon Dioxide (CO2) into said one or more four-lobe tanks 1,

- sailing said captured liquefied Carbon Dioxide (CO2) to a liquefied Carbon Dioxide (CO2) unloading terminal,

- for permanent storage,

- or for industrial consumption.

In an other embodiment of the invention, related to a method of transporting gas, comprising

- using a vessel, liquefied gas carrier 0 according to any of the embodiments above, - loading liquefied natural gas (LNG) under cryogenic conditions to one or more cryogenic cargo tanks 30 at an LNG loading terminal,

- sailing said vessel, liquefied gas carrier 0 to an LNG unloading terminal,

- unloading said liquefied natural gas (LNG) at said unloading terminal for storage, further transport or consumption,

- if necessary, sailing said vessel, liquefied gas carrier 0 to a loading terminal for liquefied carbon Dioxide (CO2),

- for permanent storage,

- or for industrial consumption.

Reference table

α inclining angle of transversely arranged axis (a15)

0 Vessel, typ. liquefied gas carrier

1 Four-lobe tank

a1 Common main central axis (1 off)

11 Main lobe (4 off)

a11 Main lobe axis (4 off)

2 Vessel hull, typ. hull of a ship

3 Vessel tank top

4 Vessel (0) with combi cargo tanks

5 Combi cargo tank vessel hull

6 Combi cargo tank vessel tank top

12 Cylinder sector outer shell, (4 off)

13a First end cover, (1 off)

13b Second end cover, (1 off)

14a First quarter spherical shell portion, (4 off)

14b Second quarter spherical shell portion, (4 off)

15a First cylindrical 45-degree cut pipe portion, (4 off)

15b Second cylindrical 45-degree cut pipe portion, (4 off)

a15 Transverse axis (a15) for cylindrical 45-degree cut pipe portion, (4 off) 16 Perforated bulkhead, (4 off)

17 Web frame, (4 off)

18 Circumferential reinforcing ring stiffener

20 Central pipe, (1 off)

30 Cryogenic cargo tank, typ. LNG cargo tank

Claims

1. A four‐lobe cargo tank (1) for transporting and/or storage of liquified gases, wherein the tank (1) comprises four main lobes (11) each with a cylinder sector outer shell (12) and main lobe axis (a11),

‐ said four main lobes (11) arranged with said four main lobe axes (a11) axial‐parallel with and about a common main central axis (a1), characterized by

‐ said four main lobes (11) joined by four web frames (17) with four corresponding diagonally arranged perforated bulkheads (16) directed outwardly from said main central axis (a1),

‐ said tank (1) further comprises first and second end covers (13a, 13b) each end cover (13a, 13b) comprising four quarter spherical shell portions (14a, 14b) each forming an end portion of said cylinder sector outer shell (12),

‐ said quarter spherical shell portions (14a, 14b) of said first and second end covers (13a, 13b) respectively, joined and closing toward said main central axis (a1) by first and second four diagonally arranged cylindrical 45‐degree cut pipe portions (15a, 15b) each arranged with its axis (a15) transverse to said main axis (a1).

2. The four‐lobe cargo tank (1) of claim 1, further comprising a central pipe (20) that is arranged co‐axial with said common main central axis (a1), wherein

‐ said central pipe (20) joining said first and second four diagonally arranged cylindrical 45-degree cut pipe portions (15a, 15b) and said four web frames (17) at either end portion of said central pipe (20),

‐ said four perforated bulkheads (16) extending radially out from said central pipe (20), and

- said central pipe (20) is arranged for routing of cargo pipes and cables into the main lobes (11).

3. The four-lobe cargo tank (1) according to claim 2, wherein said central pipe (20) further comprises;

- manholes into to the main lobes (11), such as for passages for manual human inspection.

4. The four-lobe cargo tank (1) of claim 1, further comprising at least one circumferential reinforcing ring stiffener (18) to reinforce said cylinder sector outer shell (12).

5. The four-lobe cargo tank (1) of claim 2, wherein said second four diagonally arranged cylindrical 45‐degree cut pipe portions (15b) with its transversely arranged axis (a15) inclined toward the corresponding end portion of said central common pipe (20), such that liquid draining of the tank inclines towards and into a drain in the central common pipe (20) when installed in a vertical position.

6. The four-lobe cargo tank (1) of claim 1,

wherein said liquefied gases comprise liquefied carbon dioxide.

7. The four-lobe cargo tank (1) of claim 6, further arranged for said liquefied gases to comprise liquefied natural gas, liquefied ammonia, or compressed natural gas.

8. The four-lobe cargo tank (1) of claim 1, is a pressure vessel for pressure up to 12 barg [barg=bar gauge].

9. The four-lobe cargo tank (1) of claim 8, wherein said pressure vessel is also cryogenic arranged for holding liquefied Carbon Dioxide (CO2).

10. The four-lobe cargo tank (1) of claim 1, further arranged for holding liquefied natural gas (LNG) at ambient pressure.

11. The four-lobe cargo tank (1) according to any of the preceding claims, wherein said web frames (17) protrude out between said four main lobes (11), so that said web frames (17) also serve as flanges for connection said four main lobes (11) and reinforce said four-lobe cargo tank (1).

12. The four-lobe cargo tank (1) according to any of the preceding claims, a central pipe (20) protrude the first and/or second end cover(s) (13a , 13b) and said central pipe (20) protrusion(s) is/are arranged as lifting point(s) of said four-lobe cargo tank (1).

13. A vessel, liquefied gas carrier (0) comprising at least one four-lobe cargo tank (1), according to any of claims 1-12.

14. A method of transporting gas, comprising

- using a vessel, liquefied gas carrier (0) according to claim 13,

- loading liquefied natural gas (LNG) under cryogenic conditions to said one or more four-lobe tanks (1) at an LNG loading terminal,

- sailing said vessel, liquefied gas carrier (0) to an LNG unloading terminal,

- if necessary, sailing said vessel, liquefied gas carrier (0) to a loading terminal for liquefied carbon Dioxide (CO2)

- loading captured liquefied Carbon Dioxide (CO2) into said one or more four-lobe tanks (1),

- for permanent storage,

- or for industrial consumption.

15. A method of transporting gas, comprising

- using a vessel, liquefied gas carrier (0) according to claim 13,

- loading liquefied natural gas (LNG) under cryogenic conditions to one or more cryogenic cargo tanks (30) at an LNG loading terminal,

- sailing said vessel, liquefied gas carrier (0) to an LNG unloading terminal,

- for permanent storage,

- or for industrial consumption.