GB2574051A

GB2574051A - A fluid transfer system with thermally isolating interface

Info

Publication number: GB2574051A
Application number: GB1808593.6A
Authority: GB
Inventors: Bilclough Colin
Original assignee: Techflow Marine Ltd
Current assignee: Techflow Marine Ltd
Priority date: 2018-05-24
Filing date: 2018-05-24
Publication date: 2019-11-27
Anticipated expiration: 2038-05-24
Also published as: GB2574051B; GB201808593D0

Abstract

A fluid transfer system comprises a support structure 118, a reel 102, and a cylindrical drum 114. A fluid conduit 110 extends through the drum, and connects to a hose end portion 108a on the drum. The fluid conduit is supported by a support member 120, which supports the fluid conduit so that it may rotate at the centre of the drum, and forms a thermal barrier between the conduit and the reel, especially when the system is transferring cryogenic or cold fluids such as liquefied natural gas (LNG), liquefied petroleum gas (LPG). The reel has a motor and gearbox to drive the reel clockwise or anticlockwise. In some embodiments the hub bearing 128 is a slew bearing mount. In some embodiments there may be two coaxially arranged and operatively coupled reels configured to allow communication between the two reels.

Description

A FLUID TRANSFER SYSTEM WITH THERMALLY ISOLATING INTERFACE

The present invention relates generally to the field of oil and gas production, and towards offloading and storage facilities. In particular, the present invention relates to a fluid transfer system comprising at least one hose reel assembly suitable for use with cryogenic fluid.

Introduction

Fluid transfer systems are used in a wide range of industrial applications to move a fluid (e.g. a gas or liquid) from one location (e.g. offshore floating storage units or vessels) to another (e.g. onshore depots or terminals). For example, in the oil and gas industry, a floating production, storage and offloading (FPSO) unit is a floating vessel used offshore for the processing of hydrocarbons and for storage of oil. An FPSO vessel is designed to receive hydrocarbons produced from nearby platforms or subsea template, process and store the hydrocarbons (a fluid in gaseous or liquid form) until it can be offloaded onto a tanker. The tanker will then transport the hydrocarbon fluid to a destination harbour, where the hydrocarbon fluid is transferred onshore to a depot or storage terminal. Other media, such as, chemicals (e.g. ammonia, chlorine, styrene monomer), liquefied natural gas (LNG), liquefied petroleum gas (LPG), as well as, water, wine and molasses may be transported by a tanker and then transferred between the vessel and shore or another vessel utilising a fluid transfer system. A fluid transfer system may also be used to transfer fluid between two onshore storage facilities.

A conventional loading/offloading system, such as fluid transfer system 10, is illustrated in Figures 1 ((a) - front view, (b) side view), 2 and 3. Here a rotating reel 12 is utilised for receiving, handling and storing a flexible hose 14, and which can be used for fluid (i.e. liquid and gas) transfer operations.

The reel 12 typically includes internally fixed pipework 16 fluidly connecting a first fluid port 18 that is coupleable to the hose 14 with a second fluid port 20 that is coupleable to external fluid conduits. In order to maintain a permanent connection between the reel 12 (i.e. internally fixed pipework 16) and any fixed external fluid conduits of a vessel or plant on which the reel 12 may be installed, the fluid transfer system 10 provides an interface between any rotating and nonrotating components. A schematic cross-section of such an interface is illustrated in Figure 2. The so called interface consists, for example, of a slew bearing 22 having a fixed portion 22a coupled to a support frame 24, and a rotating portion 22b mounted on the reel 12. The internal pipework 16 is then provided within the reel 12 to fluidly connect to the hose 14 when coupled to first fluid port 18. To allow relative movement between the non-rotating portion and the rotating portion, the internal pipework 16 is fitted with a swivel 26 at a pipework portion coaxial with the central rotation axis of the reel 12, i.e. where the pipework 16 emerges from the reel drum 28. Figure 3 shows a detailed perspective crosssection view of the reel assembly 12. It is shown that the internal pipework 16 is structurally supported and centralised by the reel drum wall 17, therefore, providing a direct contact between the internal pipework 16 and the reel assembly 12 (including the slew bearing 22). The internal pipework is immovably mounted to the reel drum wall 17.

Economic and legislative factors in the global shipping markets have resulted in an increased demand for transfer and bunkering operations of Liquid Natural Gas (LNG). In order to maintain LNG in its liquid state, it has to be cooled down and kept at cryogenic temperatures in the region of -168°C (degrees centigrade), i.e. ca. 105K (Kelvin). However, transferring fluid at such low temperatures creates significant problems in a conventional fluid transfer system 10.

Fluid transfer systems are commonly used worldwide in marine and commercial operations for transferring liquid cargoes.

For example, when transferring low-temperature fluid, specific components of the fluid transfer system 10 are submitted to a zone of extreme temperature 30 to which standard structural carbon steel grades are not compatible. The material of components within that zone may become extremely brittle and may therefore become critically unstable. Further, at a significant zone of thermal contraction 40 (or expansion) components may be submitted to extreme stresses as a result of material movement due to contraction (or expansion). However, even if all of the component materials used are suitable for cryogenic temperatures (e.g. Stainless steel grade 316), the magnitude of the stresses caused by contraction (or expansion) may be beyond the material’s strength limits.

Typically, though, conventional loading/offloading systems (e.g. fluid transfer system 10) are manufactured from standard grades of structural steel, and the ‘hard’ internal pipework 16 may only be manufactured from stainless steel in cases where corrosion or hygiene needs to be taken into account.

A recent study on conventional bunkering system subjected to application of cryogenic temperatures has identified design features required for safe operation of a fluid transfer system handling cryogenic fluids. In particular, the operating temperature range is between +45°C to -165 ⁰ C;

the internal design pressure is up to 18.6bar;

the support may be required to take 500kg accidental line pull at the goose neck;

the support may be required to take the weight of the internal pipeworks of up to 140kg;

the thermal contraction across an 8in (ca. 20cm) flange is ca. 1,5mm;

the thermal contraction across an 8in (ca. 20cm) pipe is ca. 0.8mm;

the axial thermal contraction of pipe runs is ca. 3.7mm per linear meter;

also, to avoid structural damage, the heat loss of steel work must not reach the slew bearing mount;

Accordingly, it is an object of the present invention to provide a fluid transfer system in form of a hose-storage system comprising at least one reel assembly adapted to improve safety during fluid transfer, as well as, minimise wear and improve durability of the fluid storage system.

Summary of the Invention

Preferred embodiment(s) of the invention seek to overcome one or more of the above disadvantages of the prior art.

According to a first embodiment of the invention there is provided a fluid transfer system comprising:

a support structure;

at least one reel, rotatably coupled to said support structure about a central rotation axis of said at least one reel, said at least one reel comprising:

a cylindrical drum member, coaxial with said central rotation axis, and adapted to couplingly engage with a fluid transfer hose end portion;

a fluid conduit assembly, operatively coupled to and extending interiorly through said cylindrical drum member, and adapted to fluidly connect the fluid transfer hose end portion with an external fluid conduit;

at least one first support member, operatively coupled to said cylindrical drum member and adapted to supportingly and movably centralise at least a first end portion of said fluid conduit assembly about said central rotation axis and provide a thermal barrier between at least said first end portion of said fluid conduit assembly and said at least one reel; and a motor drive, operatively coupled to said support structure and said at least one reel and adapted to selectively rotate said at least one reel in a clockwise and anticlockwise direction about said central rotation axis.

Advantageously, said at least one first support member may be configured to allow axial and/or radial movement of at least said first end portion of said fluid conduit assembly relative to said central rotation axis.

The present invention therefore provides the advantage to not only centralise the fluid conduit assembly, but also to provide a thermal barrier between at least a portion of the fluid conduit assembly containing, for example, the cryogenic fluid and the reel and its support structure. Consequently, thermal energy transfer between the cryogenic fluid and the structural components of the fluid transfer system is minimised (or even prevented), therefore minimising material movement (e.g. contraction) and subsequent stresses, while providing a supportingly centralising function for the internal fluid conduit assembly.

Advantageously, said at least one first support member may be operatively coupled at a central hub of said cylindrical drum member, said central hub is coaxial with said central rotation axis.

Preferably, said fluid conduit assembly may comprise a first hose coupling [port] at said first end portion, fluidly coupleable to the fluid transfer hose end portion, and a second hose coupling port at a second end portion, fluidly coupleable to the external fluid conduit.

Advantageously, said first hose coupling port may comprise a swivel member adapted to allow relative rotation between said fluid conduit assembly and the external fluid conduit about said central rotation axis.

Advantageously, said at least one reel further may comprise at least one second support member, adapted to supportingly and movably couple said second end portion to said at least one reel, and provide a thermal barrier between said second end portion of said fluid conduit assembly and said at least one reel.

Preferably, said at least one second support member may be configured to allow movement of at least said second end portion of said fluid conduit assembly relative to said at least one second support member.

Advantageously, said at least one second support member may be fixingly coupled to a portion of said at least one reel. Preferably, said at least one first support member is made of a material with thermally insulating properties. Additionally, said at least one second support member may be made of a material with thermally insulating properties.

Advantageously, said first support member and said second support member may be made from a fibre-reinforced polymer.

Advantageously, said central hub may comprise a hub bearing adapted to rotatably couple said at least one reel to said support structure. Preferably, said hub bearing may be a slew bearing mount.

Alternatively, the fluid transfer system may comprise at least two coaxially arranged and operatively coupled reels configured to allow fluid communication between said at least two reels.

Brief Description of the Drawings

Preferred embodiments of the present invention will now be described, by way of example only and not in any limitative sense, with reference to the accompanying drawings, in which:

Figure 1 (prior art) shows (a) a front view and (b) a side view of a standard loading/offloading system, such as, for example a hose reel assembly;

Figure 2 (prior art) shows a simplified schematic cross section of a conventional hose reel assembly;

Figure 3 (prior art) shows a perspective cross section view of the reel assembly, including the direct connection of the pipeworks (fluid conduit assembly) to the reel drum;

Figure 4 shows a perspective view of an example embodiment of a fluid transfer system comprising two fluidly coupled reel assemblies (a) with a flexible hose attached, and (b) without the flexible hose;

Figure 5 shows (a) a simplified schematic illustration of the reel (cross section), including pipeworks (fluid conduit assembly) centralised and thermally insulated by the hub support member of the present invention, and (b) a close-up of the hub portion and hub support member;

Figure 6 shows a detailed cross section of the hub portion of an example embodiment of the reel of the present invention;

Figure 7 shows (a) a partial schematic side view of the hose port portion of an example embodiment of the fluid transfer system, and (b) a detailed closeup view of the hose port portion;

Figure 8 shows a cross section of the hose port shown in Figure 7;

Figure 9 illustrates (a) a side view cross section of the reel of the present invention through the reel drum only and (b) a top view of the hose port;

Figure 10 illustrates the extracted fluid conduit assembly of the present invention including operatively engaged support members, and

Figure 11 shows a cross section front view of an alternative embodiment of the present invention, comprising two fluidly coupled reels.

Detailed description of the preferred embodiment(s)

The exemplary embodiments of this invention will be described in relation to hose reels and transfer of cryogenic fluids, such as liquefied LNG. However, it should be appreciated that, in general, the characterising feature(s) of this invention will work equally well for any other fluid medium at a temperature suitable to cause material effects in the fluid transfer hose and surrounding components.

For the purpose of explanation, the terms ’vertical’ and ‘horizontal’ refer to the angular orientation with respect to the surface of the earth, i.e. a reel is orientated such that ‘vertical’ means the reel is substantially perpendicular to the general orientation of the ground surface of the earth (assuming the surface is substantially flat), and ‘horizontal’ means the rotation axis of the reel is substantially parallel to the direction of the earth’s gravitational field, or the orientation of the rotation plane of the reel is parallel to the ground surface of the earth (assuming the earth’s surface is substantially flat). The term ‘lateral’ may refer to a horizontal displacement with regards to the surface of the earth. Further, the terms ‘higher’, ‘upper’ and ‘lower’ are understood in relation to the surface of the earth. The terms ‘pipework’, ‘fluid conduit’, ‘pipe(s)’ and ‘fluid passage’ may be used interchangeably and are understood to include any conduit suitable to transfer fluid from a first location towards a second location.

Figure 4 shows a perspective view of an example embodiment of a fluid transfer system 100 including two operatively coupled reel assemblies 102 and 104 (a) with flexible hoses 106a and 106b operatively coupled to respective hose coupling ports 108a and 108b, and (b) without any flexible hoses coupled to the reel assemblies 102 and 104. Each one of the two reel assemblies 102 and 104 is provided with internal pipework (i.e. an internal fluid conduit assembly) 110 that is installed between respective hose coupling ports 108a, 108b, and an external conduit port 112 configured to fluidly couple to an external pipe (not shown).

A motor and gearbox (not shown) may be operatively coupled to the support structure 118, so as so drive the reel 102 via the centrally mounted hub bearing 116 (e.g. slew bearing). For example, a motor gearbox may be configured to engage the slewing ring of the slew bearing via a pinion. Power may be provided via hydraulic, electrical or pneumatic systems. In particular, the reel assembly 102 may be provided with skid mounted hydraulic power units (HPU’s), electrical power systems, or pneumatic equipment that allows the reel assembly 102 to be operated from vessel- or plant-pneumatic ring-main systems. It is understood, by the person skilled in the art that any other suitable drive may be used.

In the example embodiment shown in Figure 4, the coupled reels 102 and 104 are of similar design and include the same characterising features of the invention. Therefore, for the purpose of describing the characterising features of the invention, reference is now made to reel assembly 102 only.

The internal pipework 110 (i.e. fluid conduit assembly) is configured, so as to provide an interface between a fixed external conduit (e.g. a vessel- or plant feed pipework) and the movable hose reel assembly 102 (including a rotatable reel drum 114 and hose coupling port 108a). Figure 5 shows a simplified schematic illustration of (a) a partially sectional side-view of the reel assembly 102, as well as, (b) a close-up view of the hub bearing 116 (e.g. slew bearing) rotatably coupling the reel assembly 102 to the reel support structure 118, or support frame. It will be appreciated that this is only a basic, typical example, and the present invention is not limited to use with only this example embodiment.

A centralising support member 120 is coupled to the reel drum 114 around a central aperture 126 of the reel drum and coaxial with the central rotation axis 122 of the reel assembly 102. The support member 120 is mounted to the reel drum 114 utilising a bracket 124 that is configured to receive and secure the support member 120. The bracket is removably mounted to the reel drum 114, but, alternatively, may be an integral part of the reel drum 114.

The support member 120 comprises a central aperture adapted to unconstrainingly centralise at least a portion of the pipework 110 relative to the central rotation axis 122, as well as, provide a thermal barrier between the pipework 110 and the reel 102 (i.e. reel drum 114, hub bearing 116, support frame 118 etc.). In particular, during use, the internal pipework 110 is unconstrained at least along the central rotation axis 122, so as to allow movement of the pipework 110 relative to the support member 120 (e.g. from longitudinal and/or radial material contraction of the pipe 110 when subjected to cryogenic temperatures) and minimise or even prevent material stresses potentially caused by extreme temperature changes.

The support member 120 is made from thermally insulating material, such as, for example, fibre-reinforced polymer (e.g. Durostone® EPM 203), therefore, minimising or preventing thermal energy transfer between the fluid conduit assembly 110 and the reel assembly 102. It is understood by the person skilled in the art that any other suitable thermally insulating material may be used. As a result, the reel drum 114 (and other reel assembly components) may be manufactured from standard structure carbon steel, so as to make it more cost effective. As the internal pipework 110 it is in direct contact with the cryogenic fluid, it is preferably made from stainless steel.

Referring now back to Figure 5 (b) and Figure 6, the internal pipework 110 is operatively coupled to the external conduit port 112 via a swivel 128 at a location of the pipework that is distal from the centralising support member 120.

Referring now to Figures 7 (a), (b), as well as, Figures 8 and 9, in order to ensure that the pipework 110 has no direct contact with the reel assembly 102, a coupling port mount 130 is provided at the hose coupling port 108a end of the internal pipework 110. In one example, the coupling port mount 130 is fixedly attached to a flange portion of the reel 102 at a location accessible with the flexible hose end, so as to allow the flexible hose 106a to be coupled to and stored on the reel drum 114. Alternatively, the coupling port mount 130 may be attached to any other suitable component of the reel assembly 102.

Figure 7 (b) shows a close-up of a cross section (Figure 7(a), X-X) of the coupling port mount 130 and secured hose coupling port 108a. Thermally insulating support elements 132 are provided between the coupling port mount 130 and the hose coupling port 108a, so as to prevent direct contact between the hose coupling port 108a and the reel structure 102. The support elements 132 are positioned about both sides of a flange member 134 that is fixed to the hose coupling port 108a of the internal pipe 110. Clearances between the internal pipework 110 and the reel structure 102 are provided based upon predetermined limits for maximum thermal expansion I contraction that may be caused by the cryogenic fluid transferred through the internal fluid conduit 110. The arrangement shown in Figure 7 (a) and (b) provides an effective thermal barrier between the pipework 110 and the wider system carbon steel reel drum structure 114 whilst, at the same time, allowing relative movement of the pipework 110 relative to the coupling port mount 130 and reel drum structure 114 (e.g. from longitudinal and/or radial material contraction of the pipe 110 when subjected to cryogenic temperatures), therefore, minimising or even preventing material stresses potentially caused by extreme temperature changes.

Figure 10 shows a perspective view of the fluid conduit assembly 110 including the operatively coupled centralising support member 120 and bracket 124, as well as, the coupling port mount 130 and support elements 132.

Figure 11 shows a cross section of a side view of a fluid transfer system 100 comprising two operatively coupled and fluidly coupleable reel assemblies 102 and 104. It is understood by the person skilled in the art that any number of reel assemblies may be coupled in a parallel arrangement, with each one of the reel assemblies comprising the characterising fluid conduit assembly 110, the respective centralising support member(s) 120 and coupling port mount(s) 130.

It will be appreciated by persons skilled in the art that the above embodiment has been described by way of example only and not in any limitative sense, and that various alterations and modifications are possible without departing from the scope of the invention as defined by the appended claims.

Claims

1. An a fluid transfer system comprising:

a support structure;

2. A fluid transfer system according to claim 2, wherein said at least one first support member is configured to allow axial and/or radial movement of at least said first end portion of said fluid conduit assembly relative to said central rotation axis.

3. A fluid transfer system according to any one of the preceding claims, wherein said at least one first support member is operatively coupled at a central hub of said cylindrical drum member, said central hub is coaxial with said central rotation axis.

4. A fluid transfer system according to any one of the preceding claims, wherein said fluid conduit assembly comprises a first hose coupling port at said first end portion, fluidly coupleable to the fluid transfer hose end portion, and a second hose coupling port at a second end portion, fluidly coupleable to the external fluid conduit.

5. A fluid transfer system according to claim 4, wherein said first hose coupling port comprises a swivel member adapted to allow relative rotation between said fluid conduit assembly and the external fluid conduit about said central rotation axis.

6. A fluid transfer system according to any one of claims 4 and 5, wherein said at least one reel further comprises at least one second support member, adapted to supportingly and movably couple said second end portion to said at least one reel, and provide a thermal barrier between said second end portion of said fluid conduit assembly and said at least one reel.

7. A fluid transfer system according to claim 6, wherein said at least one second support member is configured to allow movement of at least said second end portion of said fluid conduit assembly relative to said at least one second support member.

8. A fluid transfer system according to any one of claims 6 and 7, wherein said at least one second support member is fixingly coupled to a portion of said at least one reel.

9. A fluid transfer system according to any one of the preceding claims, wherein said at least one first support member is made of a material with thermally insulating properties.

10. A fluid transfer system according to any one of claims 6 to 9, wherein said at least one second support member is made of a material with thermally insulating properties.

5

11. A fluid transfer system according to any one of claims 9 and 10, wherein said first support member and said second support member are made from a fibrereinforced polymer.

12. A fluid transfer system according to any one of claims 3 to 11, wherein said

10 central hub comprises a hub bearing adapted to rotatably couple said at least one reel to said support structure.

13. A fluid transfer system according to claim 12, wherein said hub bearing is a slew bearing mount.

14. A fluid transfer system according to any one of the preceding claims, comprising at least two coaxially arranged and operatively coupled reels configured to allow fluid communication between said at least two reels.