FR2951803A1 - Fluid e.g. sea water, transporting conduit for producing heat energy from seas, has main tubular part comprising internal and external envelopes to define enclosure, where enclosure is partially vacuum, and contains trimming elements - Google Patents

Abstract

The conduit has a main tubular part comprising a flexible internal envelope (19) and a flexible external envelope (27) to define an enclosure (28), where the envelopes are made of Kevlar(RTM: light, strong para-aramid synthetic fiber) or Neoprene(RTM: synthetic rubber based on polychloroprene). The enclosure is partially vacuum, and contains trimming elements e.g. hollow balls. A head device and a leg device are arranged on both sides of the tubular part. Maintaining cables (3) are provided parallel to a main axis of the conduit. Independent claims are also included for the following: (1) a method for producing heat energy from seas (2) a method for manufacturing a fluid transporting conduit.

Description

FIELD OF THE INVENTION The present invention relates to a pipe intended for the transport of fluids (gas and / or liquid, for example water and / or hydrocarbons) and the use thereof. this conduct, particularly in the context of the exploitation of the thermal energy of the seas, and a method of manufacturing such a pipe.

TECHNICAL BACKGROUND In general, the fluid transport lines consist of segments of pipes of metal or of polymer material; these segments are transported to the installation site (on land or at sea) and then welded, clamped, or glued to each other as they are laid. Small diameter pipes may sometimes be available as a roll with a dedicated fitting. In particular, fluid transport pipes are needed in the field of thermal energy production of the seas, which exploits the difference in temperature between the surface waters and the deep waters of the oceans. Indeed, this technique is based on the use of a heat engine fed by a cold source (the water of the depths) and a hot source (the surface water). However, the supply by the cold source, that is to say the pumping of water from the depths, requires pipes of great length and large diameter connected to a float on the surface. Currently, such pipes are generally built on the ground, by an assembly of pipe segments which are either mechanically connected to one another, or glued in the case of polymers reinforced with fiberglass (GRP), or welded together. it is high density polyethylene (HDPE). Other materials such as steel, aluminum, concrete or elastomer are also used.

The pipe may be connected either directly to the float or indirectly via flexible hoses (jumpers on the other hand to a buoy supporting driving. In this case, the buoy is immersed at about 10 or 30 meters below the surface and maintained across the float by a set of chains stretched by small buoys. This solution has the advantage of reducing the tensile and compressive forces induced by the movement of the float on the main pipe. The bottom end of the pipe ends with a ballast and possibly a filter for seawater that is sucked. A steel cable connects the bottom of the pipe to an anchoring system placed on the bottom, either gravity or type "suction bell". Once built, the pipe, closed at the ends, is towed to the anchorage. Tugs and a multifunctional vessel provide progressive launching through ballasting of the head buoy to drain the line, connection with the anchoring system at the bottom, and deballasting of the head buoy to bring driving to its final vertical position. Alternatively, the assembly of the pipe directly at sea on the site is possible thanks to a specialized vessel on which the different segments are fixed to each other as the pipe is spun. In practice, the implementation of long-length pipes and large diameter for the exploitation of the thermal energy of the seas has proved very expensive and not robust, such pipes sometimes resistant only a few weeks before breaking . The rupture seems to be mainly due to the strong stresses exerted on the pipe by the pitch, the roll and the heave of the float. The intercalation of flexible pipes between the pipe and the float makes it possible to damp the tension and compression forces. Nevertheless, such a measure does not make it possible to lighten the torsion and bending forces induced by variable direction currents which act at different levels on the pipe. There is therefore a real need to develop an improved fluid transport conduit that is to say easier to implement and install, combining good mechanical strength with some flexibility. In particular, there is a need to develop such an improved fluid transport conduit for underwater use, the pipe then having to

R: \ 30900 \ 30947 TGEN \ 30947--091022 -document.doc- 22 October 2009 to accommodate the mechanical constraints inherent in the underwater environment, and to guarantee a low thermal transfer between the transported fluid and the environment.

SUMMARY OF THE INVENTION The invention relates first of all to a fluid transport pipe comprising a main tubular part comprising at least one inner flexible envelope and an outer flexible envelope delimiting an enclosure, the enclosure being partially empty of air and containing packing elements. According to one embodiment, the packing elements are solid balls or hollow balls or a mixture of solid balls and hollow balls. According to one embodiment, the pipe comprises, on either side of the main tubular part, a head device and a foot device, the head device comprising means for pumping fluid and means for connecting to a device. float, and the foot device comprising weighting or anchoring means. According to one embodiment, the main tubular portion comprises a plurality of tubular segments, along the main axis of the pipe, holding frames between the consecutive tubular segments, the pipe further preferably comprising a plurality of cable cables. maintained parallel to its main axis and on which the holding frames are fixed.

According to one embodiment, the tubular segments are of substantially circular section and / or substantially polygonal section. According to one embodiment, the main tubular portion has a dimension greater than 100 meters, or greater than 200 meters, or greater than 500 meters, or greater than 800 meters, according to its main axis; and / or wherein the main tubular portion has a maximum internal dimension greater than 1 meter, or greater than 2 meters, or greater than 5 meters, or greater than 8 meters, perpendicular to its main axis. The invention also relates to the use of the pipe described above for the transport of fluid in an underground environment or on the surface of the ground. The invention also relates to the use of the pipe described above for transporting fluid in an underwater environment, preferably for pumping seawater.

The invention also relates to a method for producing thermal energy of the seas, comprising pumping seawater in a pipe as described hereinabove. above and feeding a thermal cycle with pumped seawater.

The invention also relates to a method of manufacturing a pipe as described above, comprising: a) providing a driving frame comprising the inner flexible envelope and the outer flexible envelope defining the enclosure; ~ o b) the injection of the packing elements in the enclosure; c) the suction of the air contained in the enclosure; d) closing the enclosure. In a particular embodiment, the conduit frame comprises separate tubular segments and the method further comprises the step of: e) assembling the tubular segments. According to a particular embodiment, steps b) to d) and possibly e) are carried out at the installation site of the pipe, preferably at sea. The present invention makes it possible to overcome the disadvantages of the state of the technical. It provides more particularly a semi-rigid fluid transport pipe, particularly suitable for underwater use, improved over the state of the art, easier to implement and install. This pipe advantageously has a large diameter 25 and is thus suitable for large flows. In addition, its thermal conductivity can be adjusted according to the surrounding conditions. This is accomplished by a tubular structure with a flexible double jacket, providing a chamber substantially empty of air and filled with packing elements. Such a structure indeed offers: a good thermal insulation thanks to the partial vacuum and the packing elements (which preferably are themselves thermal insulation elements) and therefore a low heat transfer between the fluid transported and the surrounding environment; good mechanical strength of the jacketed wall due to the vacuum of air in the intermediate chamber; good resistance to surrounding mechanical stresses because the wall retains a relative flexibility, due in part to the flexible nature of the two envelopes and secondly the

R: \ 30900 \ 30947 TGEN \ 30947--091022 -document.doc- 22 October 2009 multiplicity of packing elements between the two envelopes, which can to a certain extent move relative to each other under the effect of external constraints and thus guarantee a relative deformability of the wall; and a great ease of installation on site (especially at sea), since before the filling of the intermediate enclosure with the packing elements and the emptying of the air in this enclosure, the pipe is completely flexible and foldable , and that these operations can therefore advantageously be performed at the last moment, on the site, just before setting up the pipe. According to some particular embodiments, the invention also has one or preferably more of the advantageous features listed below. Due to the choice of materials composing the pipe, it preferably has a high resistance to corrosion and / or a low roughness in its inner part. It is possible to provide a modular pipe, comprising a series of tubular segments. This can facilitate the design of long and large diameter pipes with good mechanical strength. This may also make it possible to adjust the mechanical properties of the pipe (pressure resistance, flexibility, density, etc.) if necessary segment by segment, for example as a function of variable environmental stresses along the pipe. In general, the invention makes it possible to simplify the deployment of the pipe on site and makes it possible to construct large diameter pipes made of polymer materials, while simultaneously ensuring the thermal insulation of the fluid vis-à-vis the external environment and the mechanical behavior of the pipe. This is why the invention is particularly well suited to submarine applications, especially for the exploitation of the thermal energy of the seas.

BRIEF DESCRIPTION OF THE FIGURES FIG. 1 schematically represents, in section, a pipe according to the invention for the extraction of cold water in the sea depths, in an operating situation.

FIG. 2 schematically represents, in section and in perspective, a detail of the wall of a pipe according to the invention, according to a particular embodiment. Figure 3 shows schematically, in section, a detail of the wall of a pipe according to the invention, according to another particular embodiment.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION The invention is now described in more detail and in a nonlimiting manner in the description which follows. This description is made in connection with the preferred embodiment wherein the pipe is placed underwater, in a substantially vertical position, and is used for pumping and transporting seawater from the depths to the surface. However, it is understood that the pipe according to the invention may optionally be used in other contexts, submarine, underground or air, for the transport and possibly the pumping of any fluid, for example in the context of the extraction or the transport of hydrocarbons. Preferably, the pipe according to the invention is used (at least over part of its length) in a substantially vertical position, and preferably it is used (at least for part of its length) in an underwater environment. Referring to Figure 1, the pipe according to the invention comprises a main tubular portion 101 framed, along its main axis, by a head device 100 and a foot device 102.

The foot device 102 represents the end portion of the pipe dedicated in particular to the entry of the fluid into the pipe, and the holding in position of the pipe. Thus, this foot device 102 may for example comprise a ballast system or, as illustrated, an anchoring system 44, in the context of underwater use. It also comprises fluid sampling means, which may simply consist of a filter-shaped plate (gate) closing the foot end of the main tubular portion 101, in the context of a seawater withdrawal. The head device 100 represents the extremal part of the pipe dedicated in particular to the outlet of the fluid from the pipe (to its transfer to other installations), and possibly to the connection of the pipe to other installations (for example the connection to a float). Generally, the head device 100 comprises in particular fluid pumping means 106.

A: A30900 \ 30947 TGEN \ 30947--091022-text depot.doc- October 22, 2009 According to the illustrated embodiment, the pipe is connected to a float 103. A bracket 104 overcomes the float 103 and underlies the cables. traction 105 which, via pulleys, connect the head device 100 of the pipe to winches at constant voltage.

Thus, the movements of the float 103 on the surface are compensated by the winches so that the conduct does not suffer and the tensions are maintained constant. The pumping means 106 comprise flexible hoses (or "jumpers") absorbing heave movements, and ensuring the transfer of fluid from the pipe to the float. This system, called moon pool type, can be replaced by other possible modes of connection to the float. The main tubular portion 101 provides fluid transport itself in the pipe. The fluid can flow directly in contact with the inner wall of the main tubular portion 101, but it can also circulate inside channels, themselves placed in the main tubular portion 101. This main tubular portion 101 can be of a alone or preferably, comprise a plurality of tubular segments connected to each other by holding frames. In this case, it is advantageous to use holding cables running along the main tubular portion 101, either in the internal space of the pipe or on the outside thereof, to ensure the mechanical strength of the pipe. all. The embodiment in which tubular segments are used makes it possible to produce pipes of great length more easily.

Typically, each tubular segment may have a length (along the main axis of the pipe) of between 5 and 20 meters, for example about 10 meters, and the main tubular portion 101 may have a dimension greater than 100 meters, or greater than 200 meters, or more than 500 meters, or greater than 800 meters.

The holding frames may for example be made of reinforced fiberglass, high density polyethylene, aluminum, steel or concrete. Referring to FIGS. 2 and 3, the wall of the main tubular portion 101 is formed by an inner flexible envelope 19 and an outer flexible envelope 27 delimiting an enclosure 28. This enclosure 28 is partially or even essentially emptied of air and contains trim elements.

In the illustrated embodiments, the pipe comprises separate tubular segments 1a, 1b, the connection of the tubular segments 1a, 1b to each other. being provided by holding frames 2. The attachment of the flexible envelopes 19, 27 to the holding frames 2 can be performed in the workshop, before the filling of the enclosure 28 with the packing elements, so as to have a pre-assembled and foldable pipe (accordion) because fully flexible. Alternatively, the holding frames 2 may be composed of two or more parts (which may be for example screwed together, or glued, or welded), in which case it is possible to assemble only in the workshop tubular segments la, 1b individual individuals terminated by a portion of the respective holding frames 2, the pipe can then be assembled at the last moment (on site, for example at sea) by assembling the different parts of the holding frames 2 between them. The section of the main tubular portion 101 may be substantially circular, or substantially polygonal. Figure 2 illustrates the case of a substantially polygonal section. In this embodiment, the holding frames 2 have a polygon shape. Figure 3 illustrates the case of a substantially circular section. In this embodiment, the holding frames 2 have a circular ring shape. Each flexible envelope 19, 27 (in each tubular segment 1a, 1b) is preferably in one piece. It may for example be made of "Kevlar" reinforced polyethylene whose thickness is adapted to the mechanical strength constraints that are envisaged (pressure, tension, etc.), or to another suitable material such as PVC or plastic. elastomer known as "neoprene" ®. The flexible envelopes 19, 27 may be either preformed at the factory, and thus already marry the dimensions of the main tubular portion 101 (it is then threaded as a sheath during assembly of the pipe), or cut to obtain the perimeter. desired, in which case the closure is provided either by a system known as "zipper" ® or by a closing bar. The shape of the main tubular portion 101 of the pipe is then essentially ensured by the holding frames 2. Typically, the maximum internal diameter of the main tubular portion 101 (and thus the tubular segments 1a, 1b) is at least 2 meters, for example at least 5 meters, for example at least 8 meters and for example about 10 meters. The maximum internal diameter is

R: \ 30900 \ 30947 TGEN \ 30947--100212-text_depot_corrigé.doc- 12 February 2010 the maximum internal dimension of the main tubular part 101, in the plane perpendicular to the axis of the pipe. The packing elements in the enclosure 28 are preferably thermal insulation elements and / or elements providing good mechanical strength, as required. These elements may be for example hollow balls (for example plastic or rubber) which can be filled with air, or even solid balls (for example metal). The choice of material for the packing elements depends on the desired characteristics of the pipe.

The dimension of the packing elements can be selected according to the desired final flexibility for the wall of the pipe. The type of lining elements used can be determined for a given tubular segment 1a, 1b (for example hollow beads only or solid beads only) or can even be variable within a tubular segment 1a, 1 b given (mixture of hollow beads and solid beads for example). The size of the packing elements (diameter of the balls for example) and / or the number / the quantity of these packing elements can also be determined for a given tubular segment la, lb or be variable within a tubular segment la, 1b given (between different parts of the same tubular segment la, lb). Thus if it is desired to create a bend in the middle of a segment, the lining elements located inside the bend will advantageously be smaller than the lining elements located outside the bend.

If, on the other hand, it is desired to obtain considerable flexibility in the middle of a tubular segment 1a, 1b, the packing elements situated at this point will have a large diameter, whereas the packing elements used for the remainder of the tubular segment , 1b will have a smaller diameter. On the other hand, the length of each tubular segment la, lb is adjusted according to the diameter of the pipe and the mechanical stresses: for example a pipe of large diameter and having to withstand high pressures will be composed of a set of segments tubular la, 1b relatively short. Depending on the on-site assembly constraints, these tubular segments 1a, 1b short can be assembled beforehand in sections of tubular segments, in the workshop, so as to have to assemble on site only sections of tubular segments.

R: \ 30900 \ 30947 TGEN \ 30947--091022-text depot.doc- 22 October 2009 In the case of a vertical deployment, and as shown in Figures 2 and 3, the tubular segments la, 1b and the frames 2 can be connected to holding cables 3 passing through the holding frames 2. The pipe can be suspended in particular to the holding cables 3, which ensures the mechanical strength of the assembly while ensuring flexibility . The tubular segments 1a, 1b are attached to the holding cables 3 through the holding frames 2. These holding frames 2 then comprise connecting elements 9 such as clamps for attachment to the holding cables 3 In the embodiment of Figure 2, the holding cables 3 are in the interior space of the pipe. When the section of the tubular segments 1a, 1b is of polygonal shape, the holding cables 3 are then preferably positioned at the vertices of the polygonal section, and they thus contribute to maintain the polyhedral shape of the pipe. Depending on the main axis of the pipe, around the holding cables 3, anti-friction tubes (not shown) can then be added to limit the wear of the flexible envelope 19 by friction against the holding cables 3.

In the embodiment of Figure 3, the holding cables 3 are on the outside of the pipe. The holding cables 3 are preferably made of steel or a synthetic material such as polyester or polypropylene. In the case (vertical or horizontal arrangement) where the pressure and tension stresses are very important, the holding frames 2 may be reinforced, particularly towards the outside, so as to receive reinforcing bars which are fixed on the periphery of the the pipe, against the outer shell, thus forming the equivalent of a "squirrel cage".

As regards the manufacture of the tubular segments 1a, 1b, the two flexible envelopes 19, 27 may for example be molded in the workshop, and crimped on the holding frames 2 (or on part of the holding frames 2), on both sides, always in the workshop. The tubular segments thus obtained are foldable (according to an accordion shape).

Just before assembling the pipe on site, or previously in the workshop, the packing elements can be injected into the chamber 28 via one or more threaded holes provided for this purpose. Once the enclosure 28 is filled with these trim elements, a device connected at the level of

R: \ 30900 \ 30947 TGEN \ 30947--091022-text depot.doc- October 22, 2009 orifices makes it possible to evacuate; optionally, at this stage, the tubular segment concerned is threaded onto an internal template of suitable shape, so as to better control the final shape of the tubular segment. The orifices are then blocked by a suitable system (for example screw and / or glue or welded plug) so as to ensure excellent vacuum strength. The air being driven into the enclosure 28, the packing elements are pressed against each other, which increases the rigidity of the tubular segment (and thus partially freezes its shape), which then holds straight, while maintaining some flexibility (adjustable depending on the size chosen for the trim elements). During the in situ assembly of the pipe, the holding cables 3, when present, are fixed on a bracket at the float and the bottom of the pipe is either ballasted or connected to a return pulley. an anchoring system, so that one can control its descent.

When the pipe is in the use position, the holding cables 3 may be ballasted or anchored at the foot device 102 to maintain the pipe substantially in the correct position. The pipe according to the invention, when it is composed of a plurality of tubular segments 1a, 1b, may comprise certain tubular segments whose wall is as described above, and other tubular segments whose wall is conventional (in particular consists of a uniform material or a stack of layers of several materials). This is useful when the constraints in terms of thermal insulation or mechanical behavior vary along the pipe. R: \ 30900 \ 30947 TGEN \ 3 0947--09 1 02 2-textedepot.doc- 22 October 2009

Claims (12)

REVENDICATIONS1. Fluid transport line comprising a main tubular part (101) comprising at least one inner flexible envelope (19) and an outer flexible envelope (27) delimiting an enclosure (28), the enclosure (28) being partially empty of air and containing packing elements. 2. A conduit according to claim 1, wherein the packing elements are solid balls or hollow balls or a mixture of solid balls and hollow balls. A conduit according to claim 1 or 2 comprising, on either side of the main tubular portion (101), a head device (100) and a foot device (102), the head device (100). comprising fluid pumping means (106) and float connecting means (105), and the foot device (102) including ballasting or anchoring means (44). 4. pipe according to one of claims 1 to 3, wherein the main tubular portion (101) comprises a plurality of tubular segments (la, 1 b), along the main axis of the pipe, holding frames (2) between the consecutive tubular segments (1a, 1b), the pipe further preferably comprising a plurality of holding cables (3) arranged parallel to its main axis and on which the holding frames (2) are fixed . 30 5. Conduit according to claim 4, wherein the tubular segments (1a, 1b) are substantially circular section and / or substantially polygonal section. 6. Conduit according to one of claims 1 to 5, wherein the main tubular portion (101) has a dimension greater than 100 meters, or greater than 200 meters, or greater than 500 meters, or greater than 800 meters, according to its main axis; and / or wherein the main tubular portion (101) has a maximum internal dimension greater than 1 meter, or greater than 2 meters, or greater than 5 meters, or greater than 8 meters, perpendicular to its main axis. 7. Use of a pipe according to one of claims 1 to 6 for the transport of fluid in an underground environment or on the surface of the ground. 8. Use of a pipe according to one of claims 1 to 6 for the transport of fluid in a submarine environment, preferably for pumping seawater. 9. A method for producing thermal energy of the sea, comprising pumping seawater in a pipe according to one of claims 1 to 6 and feeding a thermal cycle with the pumped seawater. 10. A method of manufacturing a pipe according to one of claims 1 to 6, comprising: a) providing a driving frame comprising the inner flexible envelope (19) and the outer flexible envelope (27) delimiting the enclosure (28); b) injecting the packing elements into the enclosure (28); c) aspirating the air contained in the enclosure (28); d) closing the enclosure (28). A method of manufacturing a pipe according to claim 10, wherein the pipe frame comprises separate tubular segments (1a, 1b) and the method further comprises the step of: e) assembling the tubular segments (la, lb). 12. A method of manufacturing a pipe according to claim 10 or 11, wherein steps b) to d) and optionally e) are performed at the installation site of the pipe, preferably at sea.