US-12618520-B2 - Sealed and thermally insulating tank

US12618520B2US 12618520 B2US12618520 B2US 12618520B2US-12618520-B2

Abstract

The invention relates to a sealed and thermally insulating tank for storing fluid, comprising, from the outside to the inside of the tank, a secondary thermally insulating barrier and a secondary sealing membrane, the secondary sealing membrane being secured to the secondary thermally insulating barrier, a primary thermally insulating barrier resting against the secondary sealing membrane and a primary sealing membrane resting against the primary thermally insulating barrier, the tank comprising a duct that extends along a longitudinal direction, the duct being delimited on one hand by the secondary thermally insulating barrier and on the other hand by the secondary sealing membrane, a bottom of the duct being at least in part formed by the secondary thermally insulating barrier, the tank further comprising a pressure-drop stopper that is arranged in the duct and extends between the bottom of the duct and the sealing membrane.

Inventors

Bruno Deletre
Alain Tessier
Vincent LORIN
Marc Boyeau
Vincent Berger

Assignees

GAZTRANSPORT ET TECHNIGAZ

Dates

Publication Date: 20260505
Application Date: 20210707
Priority Date: 20200717

Claims (12)

1 . A sealed and thermally-insulating fluid storage tank wherein a tank wall comprises from the exterior to the interior of the tank a secondary thermally-insulating barrier and a secondary sealed membrane, the secondary sealed membrane being anchored to the secondary thermally-insulating barrier, a primary thermally-insulating barrier resting against the secondary sealed membrane and a primary sealed membrane resting against the primary thermally-insulating barrier and being intended to be in contact with a fluid contained in the tank, wherein said secondary thermally-insulating barrier comprises a first plane portion and a second plane portion oriented at an angle to the first plane portion, a junction between the first secondary thermally-insulating barrier plane portion and the second secondary thermally-insulating barrier plane portion forming an edge, the first plane portion forming a first anchor zone for the secondary sealed membrane, the first anchor zone being at a distance from the edge, the second plane portion forming a second anchor zone for the secondary sealed membrane, the second anchor zone being at a distance from the edge, the secondary thermally-insulating barrier comprising a corner portion between the first anchor zone and the second anchor zone and comprising the edge, the secondary sealed membrane comprising a corner piece, said corner piece being sealed and comprising a first portion anchored to the first anchor zone and a second portion anchored to the second anchor zone, the corner piece further comprising a central portion between the first portion and the second portion, said central portion being free to deform relative to the secondary thermally-insulating barrier in line with the edge, the tank comprising a duct extending in a longitudinal direction parallel to the edge, said duct being delimited by the central portion of the secondary sealed membrane and the corner portion of the secondary thermally-insulating barrier, the corner portion of the secondary thermally-insulating barrier forming a bottom of the duct, the tank further comprising a pressure-drop obstacle arranged in the duct and extending between the bottom of the duct and the central portion of the secondary sealed membrane, in which said pressure-drop obstacle includes an anchor strip and a flexible portion, the anchor strip extending in a direction intersecting the longitudinal direction of the duct, the flexible portion including a plurality of flexible elements projecting from the anchor strip in the direction of the secondary sealed membrane, and a free end of the flexible elements opposite the anchor strip being in contact with the secondary sealed membrane so as to create a pressure drop for a flow circulating in the duct, said flexible elements being able to flex elastically in contact with the secondary sealed membrane.
2 . The sealed and thermally-insulating tank as claimed in claim 1 wherein the duct is parallel to the direction of terrestrial gravity or has a component perpendicular to the direction of terrestrial gravity.
3 . The sealed and thermally-insulating tank as claimed in claim 1 , wherein the anchor strip is fixed to the bottom of the duct.
4 . The sealed and thermally-insulating tank as claimed in claim 1 , wherein the pressure-drop obstacle comprises a textile layer covering flexible elements of the pressure-drop obstacle.
5 . The sealed and thermally-insulating tank as claimed in claim 1 , the tank comprising a plurality of pressure-drop obstacles arranged in the duct along the longitudinal direction of the duct.
6 . The sealed and thermally-insulating tank as claimed in claim 5 , wherein the pressure-drop obstacles of the plurality of pressure-drop obstacles are arranged in the duct at regular intervals along the longitudinal direction of the duct.
7 . The sealed and thermally-insulating tank as claimed in claim 5 , wherein the pressure-drop obstacles of the plurality of pressure-drop obstacles are arranged in the duct at irregular intervals along the longitudinal direction of the duct.
8 . The sealed and thermally-insulating tank as claimed in claim 6 , wherein the secondary thermally-insulating barrier forming the bottom of the duct comprises a plurality of spaced insulating panels and a plurality of junction zones situated between the insulating panels and the obstacles are arranged facing the insulating panels in such a manner that the junction zones at each edge of a panel are between the obstacles.
9 . A ship for transporting a cold liquid product, the ship comprising a double hull and a tank as claimed in claim 1 disposed in the double hull.
10 . A transfer system for a cold liquid product, the system comprising a ship as claimed in claim 9 , insulated pipes arranged in such a manner as to connect the tank installed in the hull of the ship to a floating or terrestrial storage installation and a pump for driving a flow of cold liquid product through the insulated pipes from or to the floating or terrestrial storage installation to or from the tanker of the ship.
11 . A method loading or offloading a ship as claimed in claim 9 , wherein a cold liquid product is routed through insulated pipes from or to a floating or terrestrial storage installation to or from the tank of the ship.
12 . A sealed and thermally-insulating fluid storage tank comprising a first tank wall and a second tank wall including from the exterior to the interior of the tank a secondary thermally-insulating barrier and a secondary sealed membrane, the secondary sealed membrane being fixed to the secondary thermally-insulating barrier, a primary thermally-insulating barrier resting against the secondary sealed membrane and a primary sealed membrane resting against the primary thermally-insulating barrier and being intended to be in contact with a fluid contained in the tank, the sealed and thermally-insulating fluid storage tank comprising a corner structure, forming an edge, disposed between the first tank wall and the second tank wall, the secondary thermally-insulating barrier including a first plane portion of the first tank wall and a second plane portion of the second tank wall, the first plane portion forming a first anchor zone for the secondary sealed membrane, the first anchor zone being at a distance from the edge, the second plane portion forming a second anchor zone for the secondary sealed membrane, the second anchor zone being at a distance from the edge, the secondary thermally-insulating barrier including a corner portion between the first anchor zone and the second anchor zone, the secondary sealed membrane of the corner structure including a corner piece, said corner piece being sealed and including a first portion of the secondary sealed membrane being anchored to the first anchor zone and a second portion of the secondary sealed membrane being anchored to the second anchor zone, the corner piece further including a central portion between the first portion and the second portion, the tank including a duct extending in a longitudinal direction parallel to the edge, said duct being delimited by the central portion of the corner piece and the corner portion of the secondary thermally-insulating barrier, the corner portion of the secondary thermally-insulating barrier forming a bottom of the duct, the tank further including a pressure-drop obstacle arranged in the duct, wherein the first portion of the secondary sealed membrane includes a first composite film and the second portion of the secondary sealed membrane includes a second composite film, wherein the central portion includes a composite flexible sealed film, wherein said central portion being free to deform relative to the secondary thermally-insulating barrier in line with the edge by extending between the first and second portions of said corner piece so that said central portion moves away from the edge and enlarges the duct when the tank is cooled, wherein the pressure-drop obstacle extends between the bottom of the duct and the central portion of the corner piece.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS AND CLAIM TO PRIORITY This application is a national stage application of International Application No. PCT/EP2021/068798 filed Jul. 7, 2021, which claims priority to French Patent Application No. 2007560 filed Jul. 17, 2020, the disclosures of which are incorporated herein by reference and to which priority is claimed. FIELD OF THE INVENTION The invention relates to the field of sealed and thermally-insulating membrane tanks for storing and/or transporting fluids, such as a cryogenic fluid. Sealed and thermally-insulating membrane tanks are employed in particular to store liquefied natural gas (LNG) which is stored at atmospheric pressure at approximately 162° C. These tanks may be installed on land or on a floating structure. In the case of a floating structure the tank may be intended to transport liquefied natural gas or to receive liquefied natural gas serving as fuel for the propulsion of the floating structure. BACKGROUND OF THE INVENTION In the prior art there are known sealed and thermally-insulating tanks for storing liquefied natural gas integrated into a supporting structure such as the double hull of a ship intended to transport liquefied natural gas. Tanks of this kind generally have a multilayer structure including in succession, in the direction of thickness, from the exterior to the interior of the tank, a secondary thermally-insulating barrier retained on the supporting structure, a secondary sealed membrane resting against the secondary thermally-insulating barrier, a primary thermally-insulating barrier resting against the secondary sealed membrane, and a primary sealed membrane resting against the primary thermally-insulating barrier and intended to be in contact with the liquefied natural gas contained in the tank. The document WO2014167214 A2 describes a multilayer sealed and thermally-insulating tank corner structure in which the secondary thermally-insulating barrier includes at the level of a corner between two walls of the tank two insulating panels forming an edge, the secondary sealed membrane including in line with said edge a flexible sealed film connecting secondary sealed membrane portions of said two tank walls. A central portion of this flexible sealed film, that is to say that between the portions of said flexible sealed film anchored to the secondary sealed membrane portions of the two tank walls, is not anchored to the secondary thermally-insulating barrier and is therefore free relative to said secondary thermally-insulating barrier. Accordingly, when the sealed and thermally-insulating tank is cooled, the thermal contraction of the insulating panels forming the edge and of the sealed membrane is absorbed by deformation of the central portion of the flexible sealed film, and said flexible sealed film is typically able to stretch to absorb loads linked to this contraction. However, if the flexible film is stretched a gap appears or increases in size between said central portion of the flexible sealed film and the thermally-insulating barrier. This gap extends all along the length of the edge. A gap of this kind forms a duct favouring convection and is therefore liable to degrade the thermal insulation performance of the tank, in particular in the context of edges having a component parallel to the direction of terrestrial gravity. SUMMARY OF THE INVENTION One idea on which the invention is based is to propose a sealed and thermally-insulating tank in which the phenomena of convection are reduced. In particular, one idea on which the invention is based is to provide a sealed and thermally-insulating tank limiting the presence of continuous circulation ducts in the thermally-insulating barriers and more particularly between the thermally-insulating barriers and the sealed membranes, in order to limit the phenomena of natural convection in said thermally-insulating barriers. In accordance with one embodiment, the invention provides a sealed and thermally-insulating fluid storage tank in which a tank wall includes from the exterior to the interior of the tank a secondary thermally-insulating barrier and a secondary sealed membrane, the secondary sealed membrane being anchored to the secondary thermally-insulating barrier, a primary thermally-insulating barrier resting against the secondary sealed membrane and a primary sealed membrane resting against the primary thermally-insulating barrier and being intended to be in contact with a fluid contained in the tank, in which said secondary thermally-insulating barrier includes a first plane portion and a second plane portion oriented at an angle to the first plane portion, a junction between the first secondary thermally-insulating barrier plane portion and the second secondary thermally-insulating barrier plane portion forming an edge, the first plane portion forming a first anchor zone for the secondary sealed membrane, the first anchor zone being at a distance from the edge, the second