MULTILAYER STRUCTURE FOR TRANSPORTING OR STORING GAS OR FOR EXPLOITING OFFSHORE OIL DEPOSITS UNDER THE SEA

Abstract

A multilayer structure for transporting or storing gas or for exploiting oil or gas deposits under the sea, including, from the inside to the outside, at least one sealing layer and at least one composite reinforcing layer, the innermost composite reinforcing layer being welded to the outermost adjacent sealing layer, the sealing layers of a composition including at least one semi-crystalline thermoplastic polymer, the Tm of which is less than 280° C., wherein at least one of the composite reinforcing layers of a fibrous material in the form of continuous fibers impregnated with a composition including at least one thermoplastic polymer, the thermoplastic polymer having a Tg greater than the maximum temperature of use of the structure (Tu), with Tg≥Tu+20° C., Tu being greater than 50° C., and a multilayer structure selected from a reservoir, a pipe or a tube for transporting or storing hydrogen being excluded.

Claims

1. A multilayer structure selected from a reservoir, a pipe or a tube for transporting or storing gas or for exploiting oil or gas deposits under the sea, comprising, from the inside to the outside, at least one sealing layer and at least one composite reinforcing layer, said innermost composite reinforcing layer being welded to said outermost adjacent sealing layer, said sealing layers consisting of a composition predominantly comprising at least one semi-crystalline thermoplastic polymer P1i (i=1 to n, n being the number of sealing layers), the Tm of which, as measured according to ISO 11357-3: 2013, is less than 280° C., said at least one thermoplastic polymer of each sealing layer may be the same or different, and at least one of said composite reinforcing layers consisting of a fibrous material in the form of continuous fibers impregnated with a composition predominantly comprising at least one thermoplastic polymer P2j, (j=1 to m, m being the number of reinforcing layers), said thermoplastic polymer P2j having a Tg, as measured according to ISO 11357-3: 2013, greater than the maximum temperature of use of said structure (Tu), with Tg≥Tu+20° C., Tu being greater than 50° C., the hydrogen being excluded from said gas transport or gas storage, and a multilayer structure selected from a reservoir, a pipe or a tube for transporting or storing hydrogen being excluded.

2. The multilayer structure according to claim 1, wherein each polymer P1i of each reinforcing layer is partially or fully miscible with each polymer P1i of the adjacent layer(s), each polymer P2j of each reinforcing layer is partially or fully miscible with each polymer P2j of the adjacent layer(s), and the polymer P21 is partially or fully miscible with polymer P11 adjacent thereto, the total or partial miscibility of said polymers being defined by the difference in glass transition temperature of the two resins, in the mixture, relative to the difference in glass transition temperature of the two resins, before mixing, and the miscibility being total when said difference is equal to 0, and the miscibility being partial when said difference is different from 0.

3. The multilayer structure according to claim 1, wherein each sealing layer comprises the same type of polymer.

4. The multilayer structure according to that claim 1, wherein each reinforcing layer comprises the same type of polymer.

5. The multilayer structure according to claim 1, wherein each sealing layer comprises the same type of polymer, and each reinforcing layer comprises the same type of polymer.

6. The multilayer structure according to claim 1, wherein it has a single sealing layer and a single reinforcing layer.

7. The multilayer structure according to claim 1, wherein said structure is a flexible pipe.

8. The multilayer structure according to claim 1, wherein said composition comprising said polymers P1 and P2 also comprises additives, enabling them to absorb radiation suitable for welding.

9. The multilayer structure according to claim 1, wherein said composition comprising said polymer P2j is transparent to radiation suitable for welding.

10. The multilayer structure according to claim 8, wherein the welding is carried out by a system selected from laser, IR heating or induction heating.

11. The multilayer structure according to claim 1, wherein said polymer P1i is a polyamide.

12. The multilayer structure according to claim 1, wherein said polymer P2j is a polyamide.

13. The multilayer structure according to claim 1, wherein said polymer P1i and said polymer P2j are polyamides.

14. The multilayer structure according to claim 11, wherein said polymer P1i is a long-chain aliphatic polyamide, or semi-aromatic.

15. The multilayer structure according to claim 12, wherein said polymer P2j is a semi-aromatic polyamide.

16. The multilayer structure according to claim 1, wherein said polymer P1i is a long-chain aliphatic polyamide, or semi-aromatic, and said polymer P2j is a semi-aromatic polyamide.

17. The multilayer structure according to claim 1, wherein it has decompression resistance and drying ability.

18. The multi-layer structure according to claim 1, wherein said structure further comprises a metallic carcass located within the sealing layer.

19. The multilayer structure according to claim 1, wherein said structure further comprises at least one outer layer, especially a metallic layer, said layer being the outermost layer of said multilayer structure.

20. The multilayer structure according to claim 1, wherein the fibrous material is selected from glass fibers, carbon fibers, basalt fibers and basalt-based fibers.

21. A method for manufacturing a multilayer structure as defined in claim 1, wherein it comprises a step of welding the reinforcing layer onto the sealing layer.

22. The method according to claim 21, wherein the welding step is carried out by a system selected from laser, infrared heating or induction heating.

23. The method according to claim 21, wherein it comprises a step of extruding said sealing layer onto a metallic carcass and a step of welding the reinforcing layer onto the sealing layer.

Description

EXAMPLES

[0157] In all examples, the reservoirs are obtained by rotational molding of the liner at a temperature adapted to the nature of the thermoplastic resin used, but in all cases below 280° C.

[0158] The tubes are obtained by extrusion of the liner at a temperature suited to the nature of the thermoplastic resin used, but in all cases less than 280° C.

[0159] In the case of epoxy, a wet filament winding process is then used, which consists of winding fibers around the liner, which fibers are pre-impregnated in a liquid epoxy bath. The reservoir is then polymerized in an oven for 2 hours.

[0160] In all other cases, a fibrous material previously impregnated with the thermoplastic resin (tape) is used. This tape is deposited by filament winding using a robot comprising a 1500 W laser heater at a speed of 12 m/min.

Example 1 (Counterexample)

[0161] Flexible wastewater transport tube (offshore application) composed of an epoxy (Tg 130° C.)—T700SC31E carbon fiber composite reinforcement and a HDPE sealing layer: no miscibility between the 2 resins (see Table I) which prevents any weld between the fibrous reinforcement and the sealing layer.

Example 2

[0162] Type IV or V gas (natural gas) storage reservoir, composed of a BACT/10T—T700SC31E carbon fiber composite reinforcement and a PA6 sealing layer: good partial miscibility between the 2 resins (see Table 1) which allows a good weld between the fibrous reinforcement and the sealing layer.

Example 3

[0163] Type IV or V gas (natural gas) storage reservoir composed of a BACT/10T—T700SC31E carbon fiber composite reinforcement and a PA66 sealing layer: good partial miscibility between the 2 resins (see Table 1) which allows a good weld between the fibrous reinforcement and the sealing layer.

Example 4

[0164] Flexible pipe used for pumping oil composed of a BACT/10T—T700SC31E carbon fiber composite reinforcement and a PA11 sealing layer deposited on an inner metallic carcass: low partial miscibility between the 2 resins (see Table 1) which leads to a poor-quality weld between the fibrous reinforcement and the sealing layer.

Example 5

[0165] Flexible pipe used for pumping oil composed of an 11/BACT/10T—T700SC31E carbon fiber composite reinforcement and a PA11 sealing layer deposited on an inner metallic carcass: good partial miscibility between the 2 resins (see Table 1) which leads to a good weld between the fibrous reinforcement and the sealing layer.

[0166] In all the examples in Table 1 below, to evaluate the miscibility of the resins, the mixtures were produced from powders with a particle size of about 150 μm on micro-DSM with a recirculation time of 1 minute after melting. All mixtures were made at 300° C., except for the epoxy-polyethylene mixture which was made at 220° C.

[0167] At the end of the mixing process, the mixture is injected into a mold to make a test piece which will be characterized in DMA.

TABLE-US-00001 TABLE 1 Ratio of the difference between the Tgs of the resin in the mixture and the Tgs of each Tg of each pure resin Tg of each resin in the (Tg P’2- pure resin mixture Tg P’1)/ (Tg P1 (Tg P’1 (Tg P’2- Mixture and and Tg P’1) Type of resin (50/50 by weight) Tg P2) Tg P’2) (%) Example 1 Epoxy     Epoxy + 130 130 100 HDPE HDPE −100 −100 Example 2 BACT/10T   BACT/10T + 178 109 12 PA6 PA6 50 94 Example 3 BACT/10T   BACT/10T + 178 110 12 PA66 PA66 60 96 Example 4 BACT/10T   BACT/10T + 178 168 76 PA11 PA11 50 71 Example 5 11/BACT/10T 11/BACT/10T + 168 115 21 PA11 PA11 50 90

[0168] Miscibility Test Results: [0169] column 4: glass transition temperature of each resin before mixing [0170] column 5: glass transition temperature of resins in the mixture [0171] column 6: ratio between the differences in glass transition temperature of the resins in the mixture and before mixing.
100% indicates non-miscibility of the resins,
<80% indicates low miscibility,
<30% indicates good but partial miscibility,
0 indicates full miscibility.