EP2953846B1

EP2953846B1 - System and method for transfer of hydrocarbon containing fluids

Info

Publication number: EP2953846B1
Application number: EP14703329.4A
Authority: EP
Inventors: Rolf ALBRIGTSEN; Jon HØVIK
Original assignee: MacGregor Norway AS
Current assignee: MacGregor Norway AS
Priority date: 2013-02-05
Filing date: 2014-02-05
Publication date: 2017-10-11
Anticipated expiration: 2034-02-05
Also published as: EP2953845B1; KR20150127062A; KR102217498B1; KR20150128693A; KR102249003B1; NO20130928A1; WO2014122159A1; KR102165383B1; NO340699B1; WO2014122123A1; EP2953845A1; EP2953846A1; KR20150128694A

Description

Field of the invention

The invention concerns a fluid transfer system and a method for transfer of cryogenic hydrocarbon based fluid from a structure to another, for example from a floating production facility for liquid natural gas (FLNG) to a liquid natural gas carrier (LNG carrier). The fluid transfer system comprises one or more transfer hoses and a support structure for supporting the hose(s). Furthermore, the transfer hose(s) comprises a first hose end for fluid communicating connection to the receiving structure and a second hose end for fluid communicating connection to the supplying structure, and the support structure comprises a column in which a first longitudinal end is attachable to one of the supplying structure and the receiving structure and a support arm connected to the other longitudinal end of the column.

Background of the invention

Transfers of hydrocarbon containing fluid between two structures may be a demanding and risky operation, in particular when the transfer is carried out in the open sea. These kinds of challenges have been extensively addressed in the last decades. One example is found in US 4'758'970 disclosing a marine loading arm as an articulated device used to on-load or off-load fluids between a vessel and a loading region such as a dock, wharf or pier. Another example is disclosed in publication US 2'922'446 describing a device for handling, manipulating and storing movable conduits fo conveying liquids between stationary and movable connection terminals. Yet another example is disclosed is disclosed in the more recent publications WO 02/008116 A1 or WO 2012/028561 A1 describing systems for transferring a load from a ship-based production and storage units to dynamically positioned shuttle tankers. Such systems comprises a loading hose which, during a loading operation, extends between an end of the ship-based unit and a bow manifold on the tanker, and which is stored on the ship-based unit when not in use. The system according to the latter publication is configured for allowing separations between the ship-based units to the tankers of about 250 to 300 meters at least partly due to a particular arrangement of buoyancy elements on the loading hose.
The above mentioned publications are configured to handle hydrocarbon containing fluid at normal temperatures.
For the handling of highly flammable and explosive cryogenic hydrocarbon containing liquids such as liquid natural gas the publication US 2004/0036275 A1 (Single Buoy Moorings Inc.) discloses an example of a loading structure for transfer of cryogenic liquids from a first storage structure to a vessel based on rigid transfer ducts and one or more swivel joints. Other rigid systems adapted for transfer of cryogenic liquids are found disclosed in publications such as US 2010/0313977 A1 (FMC Technologies SA) and WO 2013/013911 A1 (Emco Wheaton GmbH).
Common disadvantages for such rigid systems are their complexity and heavy weight, resulting in high loads on systems when wave motions cause the structures to move relative to each other. In particular, both solutions make use of a rigid loading arm positioned on FLNG for connection to a manifold structure on an LNG carrier. The arm is balanced by a counter weight and makes use of rigid ducts for the transfer of fluid from one structure to the other. The system also employs a complex swivel arrangement to enable satisfactory compensating of the relative movement between the two structures. Hence, this system requires components having large masses causing huge impact / stresses on the dedicated manifold during connection to the LNG carrier, as well as during use when the two structures are successfully connected and the fluid is being transferred. These large forces applied to system, reinforced by the relative movements between the structures, makes the dedicated manifolds on the carrier especially vulnerable. As a consequence the system sets requirements to the maximum acceptable wave height and thus restrictions to when the loading arm may be used for transfer of fluid.
Furthermore, because of the rigidity of the loading arm of the prior art system, the maximum distance between the two structures subjected to fluid transfer is more or less set, setting further restrictions of the systems applicability.
As an alternative to the rigid pipe systems for transfer of fluid, the use of flexible hoses have been suggested. However, the flexible lines are more cumbersome to handle during connection to a manifold on a receiving structure, and prior art systems have not presented satisfactory LNG-compatible solutions for the control of the flexible hoses when connection is carried out in open sea.
It is thus a need for a solution that is capable of handling the situation where one or both of the structures involved in the transfer of fluid is moving relative to each other, for example when one or both are located in water, and is able to handle transfer of cryogenic hydrocarbon containing fluids such as LNG in a sufficiently reliable way. Such cryogenic transfer operations faces additional challenges which affect the functional features of the transfer systems since the transfer of cryogenic hydrocarbon containing fluids involves hazard assessments setting significantly higher security requirements compared to more traditional transfer systems for non-cryogenic fluids.
Hence it is an object of the invention to provide a connection arrangement which also allows transfer of cryogenic hydrocarbon containing fluid outside the conservative wave restrictions hampered by the above mentioned prior art system mentioned above. It is a further object of the invention to produce a connection arrangement having low masses and low load impact during connection onto any receiving structure such as a LNG carrier. It is further an object to provide a system wherein the compensation of the relative movements between the two structures is handled in a more simplified way. It is further an object to provide a solution enabling connection to any connection assembly such as a manifold on a second structure, for instance an LNG carrier, without exposing the manifold to large forces / stresses, even during harsh weather conditions.
In one application the invention is to be used in a situation where the transfer of fluid occurs between two structures arranged side by side.

Summary of the invention

The above-identified objects are achieved by an apparatus and a method as defined in the independent claims. Further beneficial features are defined in the dependent claims.
In particular, the present invention concerns a fluid transfer system for transfer of cryogenic hydrocarbon based fluid from a supplying structure to a receiving structure. The fluid transfer system comprises at least one flexible transfer hose for transferring fluid between the supplying structure and the receiving structure, which transfer hose(s) comprises a first hose portion having a first hose end for fluid communicating connection with the supplying structure and a second hose portion having a second hose end for fluid communicating connection with the receiving structure, and where the other of the two ends of the second hose portion is arranged in fluid communication with the end of the first hose portion other than the first hose end, a support structure for supporting the at least one transfer hose, wherein the support structure comprises a column and a support arm, at least one transfer line fixed in one end to a hose end connector unit, which the connector unit is connected in fluid communication with the second hose end, and a first vertical positioning means fixed to the support structure, which vertical positioning means is configured to guide the at least one transfer line in order to, during use, vertically position the second hose end and the hose end connector unit towards a corresponding manifold connector in a second connection assembly arranged at the receiving structure. The support arm is pivotally connected to the column.
The at least one of the supplying structure and the receiving structure may be submersed in a body of water during use. Further, the transfer hose, or at least one of the transfer hoses, may be made of a flexible material.
The fluid transfer system further comprises at least one middle hose portion line attached at or in proximity of a border region between the first and second hose portion, wherein the fluid transfer system may during non-operational mode be arranged in a storage configuration in which the border region is in an elevated position relative to the second hose portion and the second hose portion is directed mainly parallel to the longitudinal length of the column with the second hose end in a downward position. Likewise, during operational mode, at least part of the support arm may be oriented in a direction transverse or mainly transverse to the column. The term "vertical positioning means" shall be interpreted as comprising any tool that may provide vertical positioning of the connector unit, for example a set of winches, sheaves and counter weights.
Further, the connector unit may preferably comprise a hose end connector valve and a hose end coupler valve, wherein the hose end connector valve and the hose end coupler valve are connected in fluid communication and the at least one transfer line is attached to the hose end connector valve.
In a preferred embodiment the transfer system further comprises a second vertical positioning means attached to the support system and configured to guide the at least one middle hose portion line in order to, during use, vertically position the border region. The length of the border region is normally below 10 % of the total length of the transfer hose and is normally located a distance from the second hose end which exceeds at least 10 % of the total length of the transfer hose, more preferably at least 20 % of the total length, for example 40 % of the total length. The border region may comprise means such as a hook for attachment of the middle hose portion line. The first hose portion and the second hose portion are for example of equal or near equal lengths.
In another preferred embodiment the second hose portion extends along at least the length of the column when the transfer system is in the storage configuration.
In another preferred embodiment the border region is, in the storage configuration, in an elevated position relative to the first hose portion, and the first hose portion extends along at least the length of the column.
In another preferred embodiment the support arm is, in the storage configuration, pivoted into an erect position relative to a direction perpendicular to the longitudinal length of the column.
This parked position enables effective drainage of at least the second hose portion.
In another preferred embodiment the fluid transfer system is configured so that the hose obtains a W-configuration when the first and second hose ends is attached in fluid communication with their respective supplying and receiving structures and the second vertical positioning means has positioned the at least one middle hose portion line such that the border region is in an elevated position relative to the vertical position of the first hose end and/or the second hose end. The W-configuration and the flexible properties of the hose ensure vertical and lateral compensations as a response to large relative height changes between the supplying structure or FLNG and the receiving structure or LNG carrier. Such compensations inter alia reduce the risk of introducing large dynamic loads on the second connection assembly while the support system in in a static position. In the W-configuration the first and second hose portion may act as an elevation compensating hose and a dynamic hose, respectively. The elevation compensating hose enables adjustment of the height of the border region in order to secure optimum working conditions for the dynamic hose, as well as providing added horizontal capacity, while the dynamic hose enables absorption of the major part of the movements of the LNG carrier with no or highly reduced introduction of large dynamic loads on the second connection assembly. In addition, the particular W-configuration helps in ensuring an effective drainage of at least the second hose portion during situations when the second hose portion and the second hose end are suspended downwardly from the middle hose portion line, thereby draining any fluid contained in this part of the hose.
In another preferred embodiment the transfer system further comprises at least one guiding line attached at least indirectly to the hose end coupler valve and a third vertical positioning means attached to the support system, the third vertical positioning means being configured to guide the at least one guiding line in order to, during use, vertically position the second hose end and the hose end connector unit towards corresponding manifold connectors in a second connection assembly arranged at the receiving structure.
In another preferred embodiment the total downward directed force experienced by the part of the line attached at the second hose end is larger than any downward directed force experienced by the part of the line situated directly above the supplying structure during use. The term "downward" is herein defined as the direction parallel to the column and directed towards the columns first longitudinal end. This particular weight distribution ensures that the second hose portion does experience a downward directed force during coupling and transfer procedures. In addition, the total downward directed force experienced by the part of the line attached at the second hose end, excluding the downward force added by the weight of the hose end coupler valve, is preferably smaller than any downward directed force experienced by the part of the line situated directly above the supplying structure during use. Hence, the release of the second hose end by disconnecting the link between the hose end connector valve and the hose end coupler valve, for example during an emergency release, results in an upwards directed force on the second hose end that ensure an at least partly maintenance of the desirable W-configuration. To ease the above mentioned preferred weight distribution the first vertical positioning means may comprise at least one sheave and at least one counter weight, wherein the at least one counter weight is attached to the transfer line such that the resulting downward force at least counteracts the downward force acting on the end of the transfer line fixed to the hose end connecter unit. This downward force is set by the combined weight including the weight of the second hose end and the hose end connector unit.
In another preferred embodiment the support arm comprises a first support arm and a second support arm pivotally connected to the first support arm. In this embodiment the at least one middle portion line may be connected to the first support arm and the at least one transfer line may be connected to the first support arm and second support arm. Furthermore, the at least one guiding line may be connected to the first support arm and the second support arm.
In another preferred embodiment the fluid transfer system comprises at least two transfer hoses suitable for transferring fluid between the supplying structure and the receiving structure, wherein, during use, at least one of the at least two transfer hoses is/are transferring fluid in liquid form in a predetermined direction and at least one of the at least two transfer hoses other than the liquid transferring hose is/are transferring fluid in gaseous form in a direction opposite to the predetermined direction for the fluid in liquid form. This liquid form fluid, for example liquid natural gas or liquid petroleum gas, is preferably kept at temperatures below 240 K.
The present invention also concerns a method suitable for transferring cryogenic hydrocarbon based fluid from a supplying structure to a receiving structure using a fluid transfer system in accordance the above mentioned features, including a second vertical positioning means (40,41,43) attached to the support system (100). The method comprises at least some of the following steps:

pivot the support arm about the pivoting connection between the support arm and the column to a position in which the second hose portion is directed mainly parallel to the column,
pivot the support arm about the pivoting connection between the support arm and the column to a position where at least part of the support arm is oriented in a direction transverse or mainly transverse to the column,
guide the at least one transfer line using the first vertical positioning means to vertically position the second hose end and the hose end connector unit towards corresponding manifold connectors in a receiving structure situated second connection assembly, and
attach the hose end connector unit in a leak free fluid communication with the receiving structure situated second connection assembly.

The method may also comprise the following step:

guide the at least one middle hose portion line using the second vertical positioning means such that the border between the first and second hose portion is in an elevated position relative to the vertical position of the first hose end and/or the second hose end,

In the following description, numerous specific details are introduced to provide a thorough understanding of embodiments of the claimed fluid transfer system and the method. One skilled in the relevant art, however, will recognize that these embodiments can be practiced without one or more of the specific details, or with other components, systems, etc. In other instances, well-known structures or operations are not shown, or are not described in detail, to avoid obscuring aspects of the disclosed embodiments.

Brief description of the drawings

Fig 1 shows a perspective view according to one embodiment of the invention where a transfer hose is installed in fluid communication between a supplying and a receiving structure.
Fig 2 shows a schematic view according to one embodiment of the invention where a transfer hose is installed in fluid communication between a supplying and a receiving structure by the means of a dedicated support structure.
Figs 3a-3m show an example installation steps according to one embodiment of the invention for connecting the transfer hose end from the supplying structure to the receiving structure by the use of the support structure.
Figs 4a-4e show in perspective view a detailed connection sequence in order to connect a multiple of transfer hose ends to corresponding connectors of a LNG manifold.
Figs 5a-5d show in perspective view (figs 5a-c) and schematic view (fig 5d) the procedure for emergency release of one or more connected transfer hose ends according to the invention.
Figs 6a-6g show in schematic view an example of installation steps according to another embodiment of the invention.
Fig 7 shows a schematic view of a bending restrictor in accordance with an embodiment of the invention.
Fig 8 shows a schematic view of the hose end prior to connection with the LNG manifold.

Detailed description of the invention

In the situation shown in Figure 1, a single transfer hose 60 is shown. However, the number of hoses to be installed in fluid communication between a FLNG 70 and a LNG carrier 80 may vary according to the specific needs, and in the particular case of transferring LNG it is considered useful to employ at least two hoses 60, in which at least one is dedicated for the transfer of LNG from the FLNG 70 to the LNG carrier 80, and at least one is dedicated for the transfer of NG from the LNG carrier 80 to the FLNG 70. The hose 60 is shown to comprise a first hose end 63b connected to the FLNG 70 and a second hose end 63a connected to a second connection assembly 90 on the LNG carrier 80.
At the FLNG side the hose(s) 60 is/are supported in respective hose guides 19 in the form of a funnel shaped guiding channel to limit the lateral movements of the hose 60 during transfer. Likewise, at the LNG carrier side the hoses 60 are installed into respective hose supports 17 in the form of a guiding channel to enable guidance of the second hose ends 63a safely into fluid communicating engagement with a LNG manifold tube 16 in the LNG manifold 90. Based on the particular W-configuration in Figure 1 (see below) each hose 60 may be conveniently defined as comprising a first hose portion 61 extending from the location where the hose 60 leaves the FLNG 70 to near the top of the peak within the W configuration, and a second hose portion 62 extending from near the top of the peak to the position where the hose enters the LNG carrier 80. Further a middle hose portion 64 is defined as the curved part forming the peak within the W configuration. In Figure 1 this middle hose portion 64 is shown in an elevated position after having been lifted by a middle hose portion line 42 at an attachment point 45. Thus, by lifting and lowering the middle hose portion line 42, the position of the middle hose portion 64 may be altered, for example as a response to any height differences between the FLNG 70 and the LNG carrier 80. This particular W configuration thus gives the advantage that the first hose portion 61 near the FLNG 70 enables easy compensation of the overall height difference between the two structures 70,80, while the second hose portion 62 near the LNG carrier 80 effectively absorbs any relative movements, thus providing control of the movement induced forces transferred to the LNG manifold 90. As a result the LNG manifold 90 is to a larger degree protected from excessive dynamic loads / stresses compared to systems using rigid ducts and swivels.
Figure 2 shows how the middle hose portion line 42 is connected to a support structure 100, which structure further comprises a column 1 connected to the FLNG 70, a first support arm 5 pivotally connected to the column 1 and a second support arm 8 pivotally connected to the first support arm 5. The lifting and lowering of the part of the middle hose portion line 42 connected to the middle hose portion 64 is performed by positioning means 40,41,43, here shown as a middle hose portion winch 40, a first middle hose portion line sheave 41 and second middle hose portion line sheaves 43. During transfer the hose 60 is generally situated above the water.
The second hose end 63a at the LNG carrier side is connected to the LNG manifold 90 by a hose end connector unit 91 in leak free fluid communication with a manifold connector 15, for example by use of a standard flange connection. The connector unit 91 further comprises a hose end connector valve 13 (or hose end valve) and a hose end coupler valve 14. Further, the manifold connecter 15 is connected in fluid communication with the LNG manifold tube 16.
During normal transfer operations a connection / disconnection between the LNG manifold 90 and the hose end connector unit 91 takes place between the hose end coupler valve 14 and the manifold connector 15, and an emergency disconnection take place between the hose end valve 13 and the hose end coupler valve 14 (see further details below).
With reference to figure 4, the hose end connector unit 91 may include hose end guide means 94,102 arranged in a position above the LNG manifold 90. Further, manifold receiving means 71 may be arranged above the end of the LNG manifold tubes 16 for receiving the hose end guide means 94,102. During connection of the hose end coupler valve 14 to the manifold connector 15, a guiding line 35 guides the hose end guide means 94,102 into the manifold receiving means 71. The load of the hose 60 is thus transferred to the manifold receiving means 71 prior to the actual connection between the connector unit 91 and the manifold connector 15.
Reverting back to Figure 2, the guiding line 35 and the middle hose portion line 42 are shown connected to the FLNG fixed support structure 100. The support structure 100 is in Figure 2 in installation mode, that is where both the first support arm 5 and the second support arm 8 extends towards the LNG carrier 80 in a direction transverse to the column 1. In this installation mode the end of the second support arm 8 is located above or almost above the LNG carrier 80, thereby allowing support for the transfer hose 60 over the entire gap between the two structures 70,80. A controlled vertical positioning of the second hose end 63a is obtained by connecting the guiding line 35 via first and second hose end line sheaves 37, 38 to the second support arm 8, and via third and fourth hose end line sheaves 34, 36 to the first support arm 5. Furthermore, lifting/lowering means such as one or more suitable winches 33 located on or near the column 1 provides the necessary outpay and retrieve of the guiding line 35.
Similar to the guiding line 35 a transfer line 27 is connected via first and second transfer line sheaves 30, 31 to the second support arm 8, and via sheaves 28, 29 to the first support arm 5. Lifting/lowering means such as a transfer line winch 23 and/or a counter weight 22 located at the column 1 provides outpay and retrieve of the transfer line 27 for the lifting and lowering of the second hose end 63a. One important difference in configuration near the second hose end 63a between the guiding line 35 and the transfer line 27 is their connection to the hose end coupler valve 14 and the hose end valve 13, respectively (see Figure 4). Furthermore, the embodiment shown in Figure 2 includes a counter weight system 22-26 comprising a counter weight 22 and a transfer line winch 23 attached to the transfer line 27, a counter weight sheave 24 attached to the counter weight 22, receiving the transfer line 27, a counter weight guiding cylinder 26 limiting the lateral movement of the counter weight 22 and a counter weight end stop 25 limiting the axial movement of the counter weight 22. The counter weight system 22-26 provides additional control of the vertical positioning of the second hose end 63a as will be explained in further details below.
The vertical positioning of the middle hose portion 64 is performed by outpaying and retrieving the middle hose portion line 42 using the above mentioned first middle hose portion line sheave 41, second middle hose portion sheave 43 and middle hose portion winch 40, all situated at the first support arm 5.
Figure 3 shows another embodiment of the inventive transfer arrangement with an alternative type of counter weight system, where figure 3a is illustrated in a storing position. In this position the second hose end 63a is disconnected from LNG manifold 90 on the LNG carrier side. In the storing position the first support arm 5 is pivoted into an erect position and the middle portion 64 of the hose 60 is in an elevated position relative to both the first and second hose portion 61, 62. Both hose portions 61,62 are therefore running approximately parallel with the column 1, thus allowing effective drainage of any remaining fluids / particulates inside the hose 60. Further, the second support arm 8 is folded downwards from the first support arm 5 with the free end of the second support arm 8 pointed downward, also in parallel with the column 1. Figure 3a further shows a hose end storing connector 105 for holding / locking the second hose end 63a when the transfer arrangement is in the storing position.
When installing the transfer hose 60, starting from the storing position shown in figure 3a, the following steps are preferably performed:

(figure 3a-c) the second support arm 8 is pivoted from its downward position to a predetermined lifted position, the latter position depending on the distance between the FLNG 70 and LNG carrier 80. Since the second hose end 63a is connected to the second support arm 8 via the guiding line 35 and the transfer line 27, the pivoting of the second support arm 8 causes a simultaneous rotation (arrow) of the hose end 63a (figure 3a and 3b), moving the second end 63a and its hose end connector unit 91 away from its downward suspended position.
(figure 3d) the first support arm 5 is pivoted downward from its erect position to a predetermined lowered position, the latter position depending on the distance between the FLNG 70 and LNG carrier 80,
(figure 3e) both the transfer line 27 and the guiding lines 35 are pulled in, which in the embodiment shown in figure 2 is achieved using the transfer line winch 24 and guiding line winch 33, respectively, and their respective sheaves 28,29,30,31,34,36,37,38, and
(figure 3f) the middle portion line 42 is paid out, which in the embodiment shown in figure 2 is achieved using the middle hose portion winch 40 and its sheaves 41,43, causing a lowering of the middle hose portion 64 downwards from the first support structure 100.

The resulting W-configuration of the transfer hose 60 after performing the above mentioned steps is shown in Figure 3f.
The movement of the first and second support arms 5,8 should now be in a position where the second hose end 63a is directed away from the FLNG 70, and where its vertical position (see Figure 3d,3e) is within reach of the LNG manifold 90. If this is not the case both the pivoting of the first and second support arms 5,8 and/or the vertical positioning of the hose 60 by the lines 27,35,42 may be adjusted until the second hose end 63a reaches a position sufficiently close to the LNG carrier 80 in order to allow the initiation of the final steps, i.e. connection to the LNG manifold 90 using the dedicated connection system 91,90. Figures 3e-f show the situation where both the first and second support arms 5, 8 are in a position transverse to the vertical support 1, that is where the free end of the second support arm 8 is furthest away from the FLNG 70, and in a proximity of the LNG manifold 90 considered sufficient for initiating the final steps.
The transfer operation may in one embodiment be finalized by performing the following subsequent steps:

(figures 3g-3h) the guiding line 35 is attached to the LNG manifold 90 by applying an assisting line 150 (see further details below) connected to the first and second support arms 5,8 via one or more assisting line sheaves 151
(figure 3i) the assisting line 150 is disconnected from the LNG manifold 90 after carrying out the attachment procedure of the guiding line 35 to the LNG manifold 90,
(figure 3i) the guiding line 35 is tightened to obtain a more stretched, and hence predictable, coupling,
(figure 3j-k) the second hose end 63a is lowered by paying out both the transfer line 27 and the hose end guiding line 35, in the embodiment shown in figure 2 using the corresponding first to fourth transfer line sheaves 30,31,28,29 and the corresponding first to fourth guiding line sheaves 37,38,34,36, respectively,
(figure 3l) the hose end guide means 94,102 provided at the second hose end 63a is positioned into the receiving means 71 provided at the LNG manifold 90 (also see figure 4 for a more detailed description of this procedure), and
(figure 3m) the second hose end 63a is further lowered in order to form a fluid tight connection between the hose end connector unit 91 and the LNG manifold 90.

Figures 4a-4c illustrates how the second hose end 63a approaches the LNG manifold 90 in accordance with the invention (see also figure 3g). In this particular embodiment three separate transfer hoses 60 are shown, all connected to a common hose end guide means 102, here in the form of a connecting bar element 102. Further, each of the second hose ends 63a comprises a clamping device 98 and a distance member 94, the latter being fixed between the clamping device 98 and the hose end guide means 102. The distance member 94 ensures a stable connection between the bar element 102 and the second hose ends 63a. The clamping device 98 may be activated manually, by springs or by a hydraulic or pneumatic cylinder unit.
At the LNG carrier side the LNG manifold 90 is provided with receiving means 71 in the form of an elongated cradle arranged in parallel with the bar element 102 and above the manifold connectors 15 and LNG manifold tubes 16. The receiving means or cradle 71 is configured to receive the common hose end guide means or bar element 102, thereby causing the desired load release.
Figure 4d illustrates in more detail disconnection of the assisting line 150 from the LNG manifold 90 after a successful attachment of the guiding line 35. The assisting line 150 is in this embodiment attached to the common hose end guide means 102 by one or more attachment lines 103. The guiding line 35 and/or attachment lines 103 are guided through dedicated bar sheaves 152 situated on the hose end guide means or bar elements 102, and fixed to an attachment line stopper 104 connected to the assisting line 150.
The assisting line 150 is lowered until the stopper 104 is situated under a fork like protrusion 107 protruding from the LNG manifold 90 from a rod fixed between the LNG manifold tubes 16. By performing appropriate alignment procedures using the guiding line 35 and the transfer line 27 the stopper 104 abuts the inside of the fork, thereby establishing a connection between the attachment line 103 (or alternatively the guiding line 37 directly) and the fork like protrusion 107. The subsequent raising of the assisting line 150 using dedicated winches removes the assisting line 150 completely from the attachment line 103.
By subsequent pulling of the guiding lines 35 the second hose end 63a is lowered to a position where the hose end guide means 102 mates with the cradle formed receiving means 71. Figure 4e shows the bar element 102 safely accommodated in the cradle 71. As mentioned, the weight of the hose end 63a is in this position effectively transferred to the LNG manifold 90.
By properly positioning and configuring the assisting line 150, the attachment lines 103, the stopper 104 and the fork like protrusion 107, the further lowering of the second hose ends 63a will, by pivoting around the bar element 102, align each second hose end 63a into a connection position with the manifold connector 15. The hose end connector unit 91 is now ready to be locked in leak free fluid communication with the LNG manifold 90, see fig 4e. The locking is carried out by engaging the clamping device 98 on the hose end coupler valve 14 to the corresponding manifold connector 15.
When performing non-emergency disconnection of the second hose end 63a from the LNG manifold 90, the same or similar procedures as for the above mentioned hose end installation steps may be carried out, but in the reverse order.
A procedure for emergency release of the second hose end 63a is also included and shown in Figures 5a-d. In an emergency situation the hose end coupler valve 14 connected to the hose end valve 13 is firstly closed in order to prevent further fluid flow from the hose end valve 13 into the hose end coupler valve 14. The clamping device 98 in figure 5 may be activated by springs or hydraulic or pneumatic cylinder units 99. For example, the activation of the cylinder unit 99 may cause an increase in the diameter of the clamping device 98, which again causes a separation of the hose end connector valve 13 from the hose end coupler valve 14, the latter being left behind on the LNG manifold 90, see Figure 5b. The second hose end 63a has transfer line(s) 27 connected on the hose end valve 13 and the transfer lines 27 are further connected via the support structure 100,5,8, sheaves 30,31,28,29,24 and counter weight 22 to the transfer line winch 23. When the emergency separation of the hose end valve 13 from the hose end coupler valve 14 is completed, the weight at the counter weight attached to the transfer line(s) 27 will cause a rapid retrieval of the second hose end 63a from the LNG manifold 90 since the total counterweight set at least partly by the attached counter weight 22 is larger that the total weight experienced at the end of the transfer line(s) 27 closest to the LNG carrier 80, see figure 5c. Figure 5d illustrates in a schematic view the transfer system after a successful emergency release. The total weight experienced by the line(s) 27 at the counter weight attachment point should however be smaller than the total weight experienced by the end of the line(s) 27 attached to the second hose end 63a if both the hose end valve 13 and the hose end coupler valve 14 are connected thereto.
Figures 6a-e shows an alternative embodiment in accordance with the invention. The above mentioned support structure 100 is illustrated as a column 1 arranged with a transverse single arm 110 (corresponding to the first and second support arm 5,8 in figures 2 and 3). As for the first embodiment the arrangement or transfer system of this alternative embodiment comprises guiding line(s) 35 connected to the support structure 100 via second guiding line sheave 38 and third guiding line sheave 34. Further, the guiding line 35 is provided with lifting and lowering means such as a guiding line winch 33 for paying out and retrieving the guiding line 35 and thereby controlling the position of the second hose end 63a. The arrangement also includes transfer line(s) 27 connected to the second hose end 63a on the hose end valve 13. The transfer line 27 is connected to the support structure 100 via second transfer line sheave 31, third transfer line sheave 28 and counter weight sheave 24, and provided with lifting and lowering means such as a counter weight 22 and/or a transfer line winch 23 for paying out and retrieving the transfer line 27. And as for the first embodiment the second hose ends 63a include guide means 102 which may be a bar member arranged in an elevated position above the hose end coupler valve 14 by a distance member 94. Receiving means 71, here shown as a cradle, is arranged elevated from LNG manifold 90 above the LNG manifold tube(s) 16 and is configured for receiving the bar member 102.
According to the embodiment of Figure 6, the coupling of the second hose end 63a to the LNG manifold 90 is enabled by use of particular coupling arrangement between the guiding line 35 and the hose end coupling unit 91. Figures 6a and 6b shows an assisting line 150, which as for the first embodiment is applied for assisting the coupling procedure. The assisting line 150 may be an extension or a branch of the guiding line 35 and is passed through a connector sheave 48 arranged on the distance member 94, above the second hose end 63a. The assisting line 150 and/or the guiding line 35 further includes a stopper 153 arranged to abut underneath the connector sheave 48, thus holding the hose end coupling unit 91 and the second hose end 63a in a levelled position. Hereinafter the assisting line 150 is defined as the line extending from the stopper 153 to the free end of the line 150. When the guiding line winch 33 is brought into an operation mode, the guiding line 35 is allowed to pay out, assisted by the abutting weight 153. The load from the second hose end 63a and its hose end coupling unit 91 is subsequently transferred to the transfer line 27, and the stopper 153 is withdrawn from the abutting connection with the connector sheave 48 by continued payout of the guiding line 35. The hose end coupling unit 91 is hence allowed to be tilted downwards in direction of the receiving assembly 90 as illustrated in Figure 6b. The assisting line 150 is subsequently connected to the LNG manifold 90, and as illustrated by the wave form of the guiding line 35 in Figure 6c, the connection is preferably performed such that the guiding line 35 has a certain slack to allow for movements of the LNG carrier 80. Any additional relative movements between the LNG carrier 80 and the FLNG 70 may be compensated by paying out and retrieving the guiding line 35 / assisting line 150 using the guiding line winch 33. The transfer line winch 23 is then brought into operation and the transfer line 27 is paid out from the winch 23 as the weight lowers the second hose end 63a along the attached guiding line 35 towards the LNG manifold 90 and into a connecting position, thereby allowing a leak free fluid communicating connection with the LNG manifold 90.
The weight experienced at the end of the transfer line 27 due to the second hose end 63a with its connection unit 91 is larger than the total weight acting on the attachment point of the counter weight 22 on the transfer line 27, thus resulting in a vertical displacement of the counter weight 22 within the counter weight guiding cylinder 26 to an elevated end stop position, for example using dedicated counter weight end stops 25 (Figures 6a-f).
When installing the hose end connector 91 in accordance with the embodiment in Figure 6, the guiding line 35 is to be attached to an attachment point provided at the LNG manifold 90. The attachment point may be the fork like protrusion 107 mentioned earlier. However, it may be any kind of blocking means that can hold the hose end guiding line 35 and/or assisting line 150 in position.
When the second hose end 63a is in a position that allows for the initiation of the transfer connection procedure, the assisting or messenger line 150 (or the guiding line 35) directs the guide means or bar element 102 into the receiving means or cradle 71. When the guide means 102 is safely accommodated into the receiving means 71, the load of the second hose end 63a is transferred to the receiving means 71. The second hose end 63a is then ready to be connected in a leak free fluid communicating connection to the LNG manifold 90.
The embodiment in accordance with the invention shown in Figure 6 also includes the emergency release mode, best illustrated in Figure 6f and 6g, i.e. disconnection of the second hose end 63a from a transfer connection position. In the emergency mode the hose end valve 13 is separated from the hose end coupler valve 14 after stopping the fluid flow between the hose end connector valve 13 and the hose end coupler valve 14. The latter remains connected to the manifold connector 15 of the LNG manifold 90, see fig 6f and 6g. The total weight experienced at the end of the transfer line 27 nearest the LNG carrier 80 due to the hose end valve 13 (separated from the hose end coupler valve 14) and the second hose end 63a is smaller than the total weight acting on the attachment point of the counter weight 22 on the transfer line 27 and set up by inter alia the counter weight 22. As a consequence the second hose end 63a and the hose end valve 13 is retrieved from the LNG manifold 90. This arrangement ensures that the disconnection of each hose end 63a may be controlled individually, and in the case where a plurality of hoses 60 are connected to the LNG manifold 90, the disconnection may be carried out for all the hose ends 63a at the same time or sequentially. As seen in Figure 6f and 6g, the transfer line(s) 27 retrieve(s) the second hose end 63a and the hose end valve 13 by use of the counter weight 22, and the guiding line(s) 35 compensate(s) for the relative movement occurring between the FLNG 70 and the LNG carrier 80.
Figure 7 shows an embodiment of the second hose end 63a with a hose end bending restrictor 130 to avoid excessive bending of the transfer hose 60 during connection / disconnection of the second hose end 63a to / from the LNG manifold 90. Figure 7 also shows in details a particular embodiment of the attachment of the transfer line 27 and the hose end connector unit 91 including the hose end valve 13, the hose end coupler valve 14, the distance member 94 and the connector sheave 48 (see above disclosure).
Figure 8 shows another embodiment of the second hose end 63a which also shows part of the receiving LNG manifold 90 comprising the LNG manifold tube 16, the manifold connector 15 and the manifold receiving means 71. In the figure the second hose portion 62, the bending restrictor 130, the hose end valve 13 and the hose end coupler valve 14 are seen connected in fluid communication with each other. An appropriate clamping device 98 is mounted onto the hose end couple valve enabling leak free coupling with the LNG manifold tube 16. The transfer line 27 is seen attached to the hose end valve 13 via a dedicated attachment means 85. Further, the guiding line 35 is shown connectable to the hose end coupler valve 14 via the stopper 153 and an aperture in the distance member 94, the latter being mounted on top of the coupler valve 14. The assisting line 150 is seen suspended from the stopper 153. By establishing a stable connection of the stopper 153 to a suitable location within the LNG manifold 90, the desired guidance of the second hose end 63a is obtained as detailed above.

In the preceding description, various aspects of the apparatus according to the invention have been described with reference to the illustrative embodiment. For purposes of explanation, specific numbers, systems and configurations were set forth in order to provide a thorough understanding of the apparatus and its workings. However, this description is not intended to be construed in a limiting sense. Various modifications and variations of the illustrative embodiment, as well as other embodiments of the apparatus, which are apparent to persons skilled in the art to which the disclosed subject matter pertains, are deemed to lie within the scope of the present as defined in the appended claims.

Reference numerals:

Column	1
First support arm	5
Second support arm	8
Hose bend (in middle hose portion)	11
Hose end connector valve / hose end valve	13
Hose end coupler valve	14
Manifold connector	15
LNG manifold tube	16
Hose support (on LNG carrier side)	17
Hose guide (on FLNG side)	19
First connection assembly / FLNG manifold	21
Counter weight (at column)	22
Transfer line winch (at column)	23
Counter weight sheave	24
Counter weight end stop	25
Counter weight guiding cylinder	26
Transfer line	27
Third transfer line sheave (on first support arm)	28
Fourth transfer line sheave (on first support arm)	29
First transfer line sheave (on second support arm)	30
Second transfer line sheave (on second support arm)	31
Guiding line winch	33
Third guiding line sheave (on first support arm)	34
Guiding line	35
Fourth guiding line sheave (on first support arm)	36
First guiding line sheave (on second support arm)	37
Second guiding line sheave (on second support arm)	38
Position means (for middle hose portion) / middle hose portion winch	40
First middle hose portion line sheave	41
Middle hose portion line	42
Second middle hose portion line sheave	43
Attachment point (on middle hose portion)	45
Connector sheave	48
Hose / transfer hose	60
First hose portion / elevation compensating hose	61
Second hose portion / dynamic hose	62
Hose end on LNG carrier side / second hose end	63a
Hose end on FLNG side / first hose end	63b
Middle hose portion / border region	64
Supplying structure / FLNG	70
Manifold receiving means	71
Receiving structure / LNG carrier	80
Attachment means (on connector valve)	85
Clamping device	89
Second connection assembly / LNG manifold	90
Hose end connector unit	91
Distance member (for guide means)	94
Clamping device / Clamping ring	98
Hydraulic or pneumatic cylinder unit	99
Support structure (for hose)	100
Hose end guide means / bar element	102
Attachment line	103
Attachment line stopper	104
Hose end storing connector	105
Fork like protrusion	107
Single arm	110
Hose end bending restrictor	130
Assisting line	150
Stopper	153

Reference numerals:

Claims

Fluid transfer system for transfer of cryogenic hydrocarbon based fluid from a supplying structure (70) to a receiving structure (80),
the fluid transfer system comprising
at least one flexible transfer hose (60) for transferring fluid between the supplying structure (70) and the receiving structure (80), the transfer hose (60) comprising a first hose portion (61) having a first hose end (63b) for fluid communicating connection with the supplying structure (70) and a second hose portion (62) having a second hose end (63a) for fluid communicating connection with the receiving structure (80), and where the other of the two ends of the second hose portion (62) is arranged in fluid communication with the end of the first hose portion (61) other than the first hose end (63b),

a support structure (100) for supporting the at least one transfer hose (60), the support structure (100) comprising a column (1) and a support arm (5,8,110), the support arm (5,8,110) being pivotally connected to the column (1),

at least one transfer line (27) fixed in one end to a hose end connector unit (91), the connector unit (91) being connected in fluid communication with the second hose end (63a), and

a first vertical positioning means (22-26,28-31) fixed to the support structure (100), the vertical positioning means (22-26,28-31) being configured to guide the at least one transfer line (27) in order to, during use, vertically position the second hose end (63a) and the hose end connector unit (91) towards a corresponding manifold connector (15) in a second connection assembly (90) arranged at the receiving structure (80), and

at least one middle hose portion line (42) attached at or in proximity of a border region (64) between the first and second hose portion (61,62),

wherein the fluid transfer system may during non-operational mode be arranged in a storage configuration in which
the border region (64) is in an elevated position relative to the second hose portion (62) and

the second hose portion (62) is directed mainly parallel to the longitudinal length of the column (1) with the second hose end (63a) in a downward position.

characterized in that the fluid transfer system further comprises
- the connector unit (91) comprising
a hose end connector valve (13) and a hose end coupler valve (14), wherein the hose end connector valve (13) and the hose end coupler valve (14) are releasably connected in fluid communication and

the at least one transfer line (27) is attached to the hose end connector valve (13).
Fluid transfer system in accordance with claim 1, characterized in that hose end connector unit (91) and the second hose end (63a) can be connected by a flange to the manifold connector (15).
Fluid transfer system in accordance with claim 2, characterized in that the transfer system further comprising
at least one guiding line (35) attached to the hose end coupler valve (14) and

a third vertical positioning means (33,34,36-38) attached to the support structure (100), the third vertical positioning means (33,34,36-38) being configured to guide the at least one guiding line (35) in order to, during use, vertically position the second hose end (63a) and the hose end connector unit (91) towards corresponding manifold connectors (15) in a second connection assembly (90) arranged at the receiving structure (80).
Fluid transfer system in accordance with one of the preceding claims,
characterized in that
the total downward directed force experienced by the part of the line (27) attached at the second hose end (63a) is larger than

any downward directed force experienced by the part of the line(s) (27) situated directly above the supplying structure (70) during use.
Fluid transfer system in accordance with one of the claims 2-4,
characterized in that
the total downward directed force experienced by the part of the line (27) attached at the second hose end (63a), excluding the downward force added by the weight of the hose end coupler valve (14), is smaller than

any downward directed force experienced by the part of the line(s) (27) situated directly above the supplying structure (70) during use.
Fluid transfer system in accordance with anyone of the preceding claims, cha
racterized in that
the first vertical positioning means (22-26,28-31) comprising

at least one sheave (28-31) and

at least one counter weight (22),
wherein the at least one counter weight (22) is attached to the transfer line (27) such that the resulting downward force at least counteracts the downward force acting on the end of the transfer line (27) fixed to the hose end connecter unit (91).
Fluid transfer system in accordance with anyone of the preceding claims,
characterized in that
the transfer system further comprises a second vertical positioning means (40,41,43) attached to the support structure (100), the second vertical positioning means (40,41,43) being configured to guide the at least one middle hose portion line (42) in order to, during use, vertically position the border region (64).
Fluid transfer system in accordance with anyone of the preceding claims,
characterized in that, in the storage configuration, the second hose portion (62) extends along at least the entire length of the column (1).
Fluid transfer system in accordance with anyone of the preceding claims,
characterized in that, in the storage configuration, the border region (64) is in an elevated position relative to the first hose portion (61), which first hose portion (61) extends along at least the entire length of the column (1).
Fluid transfer system in accordance with anyone of the preceding claims,
characterized in that, in the storage configuration, at least part of the support arm (5,8,110) is pivoted into an erect position relative to a direction perpendicular to the longitudinal length of the column (1).
Fluid transfer system in accordance with anyone of the preceding claims,
characterized in that the support arm (5,8,110) comprising
a first support arm (5) and

a second support arm (8) pivotally connected to the first support arm (5).
Fluid transfer system in accordance with anyone of the preceding claims,
characterized in that
the fluid transfer system comprising
at least two transfer hoses (60) for transferring fluid between the supplying structure (70) and the receiving structure (80), wherein, during use,

at least one of the at least two transfer hoses (60) is/are transferring fluid in liquid form in a predetermined direction and

at least one of the at least two transfer hoses (60) other than the liquid transferring hose(s) is/are transferring fluid in gaseous form in a direction opposite to the predetermined direction for the fluid in liquid form.
Method for transferring cryogenic hydrocarbon based fluid from a supplying structure (70) to a receiving structure (80) using a fluid transfer system in accordance with anyone of claims 1-12, including a second vertical positioning means (40,41,43) attached to the support structure (100),
wherein the method comprises at least some of the following steps:
- pivot the support arm (5,8,110) about the pivoting connection between the support arm (5,8,110) and the column (1) to a position in which the second hose portion (62) is directed mainly parallel to the longitudinal length of the column (1),

- pivot the support arm (5,8,110) about the pivoting connection between the support arm (5,8,110) and the column (1) to a position where at least part of the support arm (5,8,110) is oriented in a direction transverse or mainly perpendicular to the longitudinal length of the column (1),

- guide the at least one transfer line (27) using the first vertical positioning means (22-26,28-31) to vertically position the second hose end (63a) and the hose end connector unit (91) towards corresponding manifold connectors (15) in a second connection assembly (90) arranged at the receiving structure (80), and

- attach the hose end connector unit (91) in a leak free fluid communication with the second connection assembly (90).