RU2786066C2 - Use of poly(etherketoneketone) (pekk) for production of components with low gas permeability for transportation of oil liquids - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to the use of poly(etherketoneketones) (hereinafter – PEKK) as a gas-barrier layer and, especially, for the production of components, which have low permeability for gases, such as CO₂ or H₂S. The invention also relates to a pipe, which is used for the transportation of oil liquids. The pipe contains a layer designed for being in contact with an oil output flow, while the specified layer contains PEKK and has permeability for CO₂ at 130°C of less than 10^-8 cm³ for a thickness of 1 cm and a surface area of 1 cm², and per second and per bar of pressure of CO₂, and/or permeability for H₂S at 130°C of less than 10^-8 cm³ for a thickness of 1 cm and a surface area of 1 cm², and per second and per bar of pressure of H₂S, wherein amount of CO₂ and H₂S is measured using a chromatograph, respectively. The invention also proposes a number of methods for the production of such a pipe.

EFFECT: invention provides obtainment of a pipe, which has low gas permeability, especially to corrosion samples, CO₂ and H₂S, even under extreme operational conditions.

17 cl, 3 tbl, 1 ex

Description

Technical field

The present invention relates to the use of poly(ether-ketone ketones) (PEKK (PEKK)) as a gas barrier layer, and especially for the production of components that have a low permeability to gases such as CO ₂ or H ₂ S. More specifically, the invention relates to pipes that are used to transport petroleum liquids.

State of the art

There are many sectors that require materials that have low gas permeability even under harsh conditions.

For example, in offshore oil production, the produced hydrocarbons must be transported over long distances and under extreme conditions. This is because the pipes used can be subjected to pressures in excess of 100 bar and high temperatures in excess of 90°C or even 130°C for extended periods of time. During transport of an oil effluent under such conditions, some of the gaseous acidic compounds that are present in the transported hydrocarbons, such as H ₂ S and CO ₂ , can lead to very expensive corrosion damage if they reach metal components. Corrosion poses a serious risk due to significant stresses on the pipes, not only due to their mass, but also due to the high pressure of the oil effluent and the marine environment. The phenomena of migration and corrosion are exacerbated at high temperatures.

There are two known types of tubular structures for transporting oil effluents.

In rigid structures, the pipe may comprise a metal pipe protected by an internal polymer layer to improve corrosion resistance. The inner polymeric layer may take the form of a lining or an adhesive coating obtained, for example, by coating with a powder material.

Flexible structures may comprise, from the inside to the outside of the pipe, a metal frame consisting of metal strips wound in a spiral at short pitch to resist crushing, an extruded polymer layer to act as a sealing sheath, a roof of bonded metal wires to resist internal pressure, a second extruded polymeric layer as a sealing sheath, one or more layers of stretchable braid consisting of metal wires wound in a spiral at certain angles, and finally an outer polymeric sheath serving to protect the pipe from its environment. Such designs are called "rough" pipes.

If there is no frame in such pipes, they are called "smooth" pipes. In such latter structures, the oil effluents are in direct contact with the polymer of the sealing layer.

To improve the temperature resistance of such pipes, US 2006/0229395 A1 proposes the use of internal coatings or pipelines extruded from thermoplastic polymers that have high chemical resistance and a high softening point, such as poly(phenylene sulfides) (PPS) or polyaryletherketones (PAEK (PAEK)). The document makes no mention of the gas permeability of such polymers.

Document WO 2014/199033 proposes adding alkali metal or alkaline earth metal oxides to the polymer to neutralize CO ₂ and H ₂ S by chemical reaction. The proposed polymers are polymers from the class of vinylidene-fluoride copolymers. This approach, however, is difficult to implement, and the addition of fillers tends to degrade the mechanical properties of polymers, especially elongation at break.

In addition, patent application WO 2012/107753 A1 proposes to reduce the risk of failure of a pipe for transporting hydraulic fluids under pressure by reducing the residual stress in it by allowing slower and therefore more uniform crystallization of the polymer. Among the polymers considered, PECK is mentioned, although the latter is not represented in the examples. Also in this document there is no mention of the gas permeability of these polymers.

Despite existing progress, there remains a need for pipes that have low gas permeability, especially to corrosive samples, CO ₂ and H ₂ S, even under extreme operating conditions. The reason is that a polymer exhibiting higher permeability characteristics will increase the service life of the pipes and/or reduce the thickness of the barrier layer and hence the weight of the pipe.

The essence of the invention

The present invention is based on the discovery that poly(ether-ketone ketone) (PEKK) shows very promising gas barrier properties, especially with respect to CO ₂ and H ₂ S, and such properties, in particular, are markedly superior to those of poly(ether-ketone) (PEEK (PEEK )).

In a first aspect, therefore, the invention provides the use of PECC to reduce the permeability to CO ₂ and H ₂ S of a component intended to come into contact, directly or indirectly, with an oil effluent.

The term "component in contact with an oil effluent" means a layer in direct or indirect contact with said effluent.

The term "component in direct contact with the oil effluent" means in particular the inner layer of the pipe.

The term "component in indirect contact with the oil effluent" means especially a layer which is not an inner layer but is placed around the inner layer, where said inner layer may or may not be sealed.

PECK preferably has a degree of crystallinity greater than 5 wt%.

PECK advantageously has a T:I (T:I) ratio of 35 to 100%, preferably 55 to 85%, and more particularly 60 to 80%.

The CO ₂ permeability of the component at 130° C. is preferably less than 10 ^-8 cm ³ CO ₂ for a thickness of 1 cm and a surface area of 1 cm ² per second and per bar of CO ₂ pressure, the CO ₂ permeate being measured by GC (GC ).

The permeability to the H ₂ S component at 130° C. is preferably less than 10 ^-8 cm ³ for a thickness of 1 cm and a surface area of 1 cm ² per second and per bar of H ₂ S pressure, the H ₂ S penetration being measured by GC.

The component is preferably selected from a pipe, a sheath or seal and an inner lining, especially for transporting an oil effluent.

In a second aspect, the invention provides a pipe, especially for transporting an oil effluent, comprising a layer intended to be in contact with the oil effluent, characterized in that said layer intended to be in contact with the oil effluent contains PECK and is permeable to CO ₂ at 130°C less than 10 ^-8 cm ³ for a thickness of 1 cm and a surface area of 1 cm ² per second and per bar of CO ₂ pressure, and/or a permeability for H ₂ S at 130°C less than 10 ^{- 8} cm ³ for a thickness of 1 cm and a surface area of 1 cm ² per second and per bar of H ₂ S pressure, with the permeated CO ₂ and H ₂ S measured by GC, respectively.

In one embodiment, said layer intended to be in contact with the oil effluent is a sealing sheath surrounding a metal frame.

In another embodiment, said layer intended to be in contact with the oil effluent does not contain reinforcing fibers.

Said layer intended to be in contact with the oil effluent is preferably surrounded by at least one mechanical strengthening layer.

In one embodiment, at least one work hardening layer is made of metal.

In another embodiment, at least one work hardening layer is made of a composite material. In this case, the composite material may be, for example, a thermoplastic composite, especially based on polyamide, polyethylene, especially PE-RT (abbreviation for "elevated polyethylene"), PECK or PVDF (PVDF), and may also contain carbon fibers, especially continuous carbon fibers, aramid fibers or also glass fibers.

In one embodiment, the pipe according to the invention also contains flexible metal fittings. In another embodiment, the pipe also contains a rigid metal reinforcement.

In a third aspect, the invention also provides a number of methods for producing a pipe according to the invention.

When the pipe to be produced, in particular repaired, is a rigid pipe, the method according to the invention comprises the steps of:

(a) obtaining a pipe containing PECK, of the appropriate size; and

(b) inserting said pipe into a metal pipe to form a lining.

When the pipe to be produced is a flexible rough pipe, the method of the invention includes the steps of:

(a) obtaining a metal frame;

(b) extruding around the specified metal framework, at least one layer of the composition containing PECK, extrusion with a T-shaped head; and

(c) mounting a roof around the resulting structure;

(d) mounting one or more layers of stretch braid; and

(e) extruding an outer polymeric shell around the resulting assembly.

When the pipe to be produced is a flexible smooth pipe, the process according to the invention includes the steps of:

(a) extruding at least one layer of the composition containing PECK, extrusion with a T-shaped head; and

(b) mounting a roof around the resulting structure;

(c) mounting one or more layers of stretch braid; and

(d) extruding an outer polymeric shell around the resulting assembly.

Other characteristics and advantages of the method according to the invention will become apparent from reading the detailed description below.

Detailed description of the invention

In accordance with the invention, the use of poly(etherketone ketone) (PEKK) is proposed for the production of components that have low gas permeability and especially with respect to CO ₂ and/or H ₂ S.

PECK

" PEKK " refers to PAEK (PAEK) polymers that contain units of the formula (-Ar-X-) and also units of the formula (-Ar'-Y-) in which:

- Ar and Ar' each means a divalent aromatic radical;

- Ar and Ar' may preferably be selected from optionally substituted 1,3-phenylene and 1,4-phenylene;

- X is a carbonyl group;

- Y means a group selected from an oxygen atom.

Poly-ether-ketone-ketone (PEKK) contains a sequence of repeating units of the type -(Ar ₁ -O-Ar ₂ -CO-Ar ₃ -CO) _n -, and each of Ar ₁ , Ar ₂ and Ar ₃ means independently divalent aromatic a radical, preferably phenylene.

In the formula above, as in all the formulas that follow, n stands for an integer.

The bonds on either side of each Ar ₁ , Ar ₂ and Ar ₃ unit may be of the para or meta or ortho type (preferably the para or meta type).

In some embodiments, the PECK contains a sequence of repeating units of formula (IA) and/or formula (IB):

(IA)

.(IB)

.

Units of formula (IA) are units derived from isophthalic acid (or units I (I)), while units of formula (IB) are units derived from terephthalic acid (or units T (T)).

In the PECC used in the invention, the mass fraction of T units relative to the sum of T and I units can be in the range from 0 to 5%, or from 5 to 10%, or from 10 to 15%, or from 15 to 20%, or from 15 to 20% or 20 to 25% or 25 to 30% or 30 to 35% or 35 to 40% or 40 to 45% or 45 to 50% or 50 up to 55%, or from 55 to 60%, or from 60 to 65%, or from 65 to 70%, or from 70 to 75%, or from 75 to 80%, or from 80 to 85%, or from 85 to 90%, or 90 to 95%, or 95 to 100%.

Ranges from 35 to 100%, in particular from 55 to 85% and even more particularly from 60 to 80% are particularly suitable. In all ranges presented in this patent application, the limit values are included, unless otherwise noted.

PECC preferably has an intrinsic viscosity of 0.4 to 1.5 dl/g, preferably 0.6 to 1.4 dl/g, more preferably 0.8 to 1.2 dl/g, in 96% sulfuric acid.

The degree of crystallinity of the polymer can influence the gas permeability characteristics. Indeed, it has been noted that the gas permeability of PECC, especially with respect to CO ₂ and H ₂ S, decreases with increasing crystallinity. It is therefore preferable that the PECC used has a maximum degree of crystallinity, preferably more than 5%, especially more than 15% and very preferably more than 25%. In the PECC used in the invention, the mass fraction of the crystalline PECC may substantially vary from 0 to 1%, or from 1 to 5%, or from 5 to 10%, or from 10 to 15%, or from 15 to 20%, or 20 to 25%, or 25 to 30%, or 30 to 35%, or 35 to 40%, or 40 to 45%, or 45 to 50%.

For some applications, it may be beneficial to use amorphous PECC. Amorphous PECC means PECC with a melting enthalpy of less than 10 J/g, which is measured by DSC in accordance with ISO 11357-3:1999.

The degree of crystallinity can be measured using Wide Angle X-ray Scattering (WAXS). As an example, analysis can be performed with WAXS on a Nano-inXider® device under the following conditions:

- wavelength: main Kα1 copper line (1.54 angstroms)

- generator power: 50 kV - 0.6 mA

- observation mode: transmission

- counting time: 10 min.

The result is an intensity spectrum of the scattered radiation as a function of the diffraction angle. This spectrum makes it possible to determine the presence of crystals when peaks are visible in the spectrum, in addition to the amorphous areola.

In the spectrum, the area of the crystalline peaks (designated AC) and the area of the amorphous areola (designated AH) can be measured. The mass fraction of crystalline PECK in total PECK is then evaluated using the ratio (AC)/(AC+AH).

In general, it is preferable that the content of crystalline PECK be relatively high, for example, greater than or equal to 5%, or greater than or equal to 10%, or even greater than or equal to 15%, in order to obtain components having high mechanical characteristics. Another advantage of a high degree of crystallinity is better mechanical properties, including properties at high temperature, in terms of, for example, modulus or flow stress.

An alternative possibility is to calculate the degree of crystallinity from the melting enthalpy of PECC measured, for example, by DSC, by dividing the melting enthalpy of PECC having a crystallinity of 100% by weight.

PECK resin may contain one or more additional polymers, belonging or not belonging to the PAEK class.

The weight content of PECC in the PECC resin is preferably greater than or equal to 50%, preferably greater than or equal to 60%, especially greater than or equal to 70%, preferably greater than or equal to 80%, and more preferably greater than or equal to 90%. In some embodiments, the PECC resin consists essentially of one or more PECC.

The resin may contain additives such as fillers and functional additives. Accordingly, the resin may contain reinforcing fillers, especially continuous fibers, especially carbon fibers. Fillers and/or functional additives can also be dispensed with.

The resin in particular may contain one/one or more phosphates or phosphate salts in order to improve the melt stability of PAEK.

In accordance with the invention, components produced using PECC have low gas permeability, especially with respect to CO ₂ and/or H ₂ S. In some applications, such as, for example, subsea oil production, pipes are needed that are stable and that retain these properties in tough or even extreme operating conditions in order to limit the migration of gaseous samples and reduce corrosion. Such conditions typically include an operating temperature greater than 100°C, preferably greater than 110°C, in particular greater than 120°C and even preferably greater than 130°C and/or a pressure greater than 10 bar, preferably greater than 20 bar, in particular more than 30 bar and very preferably more than 40 bar or even more than 50 or even more than 100 bar.

The component advantageously has a CO ₂ permeability at 130°C of less than 10×10 ^-8 , in particular 5×10 ^-8 , in particular 1×10 ^-8 , preferably 5×10 ^-9 and in particular less than 1×10 ^{- 9} cm ³ CO ₂ for a thickness of 1 cm and a surface area of 1 cm ² per second and per bar of CO ₂ pressure, the amount of CO ₂ being measured by GC.

Moreover, the permeability to the H ₂ S component at 130°C is preferably less than 10×10 ^-8 , especially 5×10 ^-8 , especially 1×10 ^-8 , preferably 5×10 ^-9 , more preferably less than 1× 10 ^-9 , in particular less than 5×10 ^-10 and very preferably less than 1×10 ^-10 cm ³ H ₂ S for a thickness of 1 cm and a surface area of 1 cm ² per second and per bar of H ₂ S pressure, whereby the amount H ₂ S is measured using GC.

In one embodiment, the component may contain two or more layers. In particular, it can combine at least one layer containing PECK with at least one layer of another material, especially PVDF, polyamide, polyethylene, especially PE-RT, or also a material acting as an assembly binder. corresponding layers to each other.

Pipes

In some technical sectors, especially in the field of oil production, there is a search for materials that combine temperature resistance and resistance to chemicals with low gas permeability, especially relatively acidic compounds of CO ₂ and H ₂ S. The reason is that such compounds present in oil , are acidic and corrosive to metal components. The use of PECC is thus particularly useful for the production of components used in the transport of liquid and/or gaseous hydrocarbons, referred to herein as oil effluents.

In a second aspect, therefore, the invention relates to a pipe containing a layer intended to be in contact with an oil effluent, characterized in that said layer intended to be in contact with an oil effluent contains PECK and has a permeability to CO ₂ at 130 °C less than 10 ^-8 cm ³ CO ₂ for a thickness of 1 cm and a surface area of 1 cm ² per second and per bar of CO ₂ pressure, and/or the permeability to H ₂ S at 130°C is preferably less than 10×10 ^-8 , especially 5×10 ^-8 , especially 1×10 ^-8 , preferably 5×10 ^-9 , more preferably 1×10 ^-9 , in particular 5×10 ^-10 and very preferably 1×10 ^-10 cm ³ H ₂ S for a thickness of 1 cm and a surface area of 1 cm ² per second and per bar of H ₂ S pressure, with CO ₂ and H ₂ S being measured by GC.

Such pipes may be useful in production equipment for transporting oil effluent or also for transporting other mixtures containing CO ₂ and/or H ₂ S under severe pressure and/or temperature conditions.

Proposed, in particular, pipes for transporting hydrocarbons, especially mixtures containing at least one gaseous acidic compound, especially a gas selected from CO ₂ and H ₂ S.

These pipes can be of different designs depending on their particular application and associated stresses.

Therefore, the pipes, for example, may be single-layer pipes, or may also contain two, three, four, or in fact even more layers. Multilayer pipes are particularly capable of withstanding mechanical or thermal stresses at outer layers that are not in contact with oil effluents.

Typically, the layer intended to be in contact with the oil effluent forms the inner layer of the pipe. However, the invention also covers the case in which this layer is in indirect contact with oil effluents. In one embodiment of the invention, therefore, the pipe contains a hermetic or non-hermetic inner layer, for example, a metal frame, which is surrounded by a layer containing PECK. In this case, the oil effluent passes at least partially through the leaky inner layer and therefore comes into indirect contact with the layer containing PECC.

In one embodiment, the framework is surrounded by a membrane containing PECK. In another embodiment, the membrane consists of a plurality of layers, and contains at least one additional layer to the layer containing PECK, made of another polymer, such as, for example, PVDF, polyamide, polyethylene, especially PE-RT, or also a material , acting as a binder to assemble the respective layers to each other.

The specified multilayer membrane, for example, may include a layer containing PECK, and a layer based on PVDF. PVDF is a material that is particularly valuable due to its flexibility and its chemical and heat resistance (up to 280°C), although its gas permeability means it offers little corrosion protection. Advantageously, the PVDF layer can be placed in contact with the carcass and the PECC-containing layer can be placed on the outside of the carcass. Other layers may be placed between these two layers forming the membrane.

The layers forming the membrane can be connected to each other, for example by means of mechanical fastening, in other words by engaging the roughnesses present on their respective surfaces.

Therefore, the pipe may be of the type referred to as "coarse". In this type of pipe, the layer intended to be in contact with the oil effluent may form a sealing sheath surrounding the metal frame. The frame is formed by a metal strip wound in a spiral, which serves to increase the resistance of the pipe against external pressure. Pipes of this type also contain a dome made of, for example, strongly bonded wires to guarantee resistance to internal pressure inside the pipe, and layers of stretch braid, consisting of metal wires wound in a spiral at a certain angle, allowing the pipe, in particular, to exhibit a better tensile strength.

On the other hand, the pipe may be of the type referred to as "smooth". This type of pipe does not have a metal frame. The oil effluent can thus be in direct contact with the PECC-containing layer. In both types of pipe, the layer intended to be in contact with the oil effluent may or may not contain reinforcing fibres. In any case, in addition to low gas permeability, especially with respect to CO ₂ and H ₂ S, PECC has the advantage of excellent abrasion resistance, especially when it is formulated with other agents, especially reinforcing fibers, especially carbon fibers. Accordingly, the PECC inner layer provides effective resistance to abrasion caused by particulate matter, which is often present in the effluents.

Pipes according to the invention generally additionally comprise, as explained above for coarse pipes, at least one layer of mechanical reinforcement forming a reinforcement to resist external and internal pressure. However, there are also flexible pipes made entirely of thermoplastic polymers, such as those sold by Airborne. In such pipes, the reinforcement layers and optional metal fittings are replaced by reinforcing elements consisting of thermoplastic composites.

At least one mechanical strengthening layer may be made of metal. In this case, it may be a metal tube or, for greater flexibility, it may also be a coil of metal wires or of a metal material.

The work hardening layer, on the other hand, may be made of a composite material. The composite material preferably consists of a polymer reinforced with reinforcing fibres. The polymer is preferably a high quality thermoplastic polymer, for example a polymer from the class of polyamides, polyethylene, especially PE-RT, PVDF, PAEK, especially selected from PECC and/or PEEK (PEEK). In the composite, the polymer is reinforced with reinforcing fillers, especially fibers, especially carbon fibers, or aramid fibers, or glass fibers. This type of work-hardening layer containing PECC can also be replaced by a metal frame and roof, where appropriate, to form a flexible smooth tube.

In one embodiment, the pipe also includes a flexible external reinforcement. In another embodiment, the pipe also contains a rigid outer reinforcement.

The layer intended to be in contact with the oil effluent can in particular be in the form of a tube, a shell or a sealed layer, or also an inner cover. The inner lining may in particular be a lining intended to be inserted into pipes, especially metal pipes, in order to repair them.

In a third aspect, the invention provides a method for the production of pipes as described above.

In particular, when the layer intended to be in contact with the oil effluent takes the form of a pipe or shell, it can be obtained, for example, by extrusion or coextruding. When the layer is in the form of an inner coating, it can be obtained, for example, by coating with a powder material.

A multilayer component as described above can also be obtained by extrusion sheathing or also by winding strips and subsequent welding. In this case, the layer intended to be in contact with the oil effluent is also referred to as the sealed layer or sheath.

More specifically, when the pipe to be manufactured or repaired is a rigid pipe, the method of the invention includes the steps of:

(a) obtaining a pipe containing PECK, of the appropriate size; and

(b) inserting said pipe into a metal pipe to form a lining.

In one embodiment, the pipe containing PECK may also contain one or more additional layers, for example, of PVDF, polyamide, PE-RT or also a material acting as a binder to assemble the respective layers to each other.

When the pipe to be produced is a flexible rough pipe, the method of the invention includes the steps of:

(a) obtaining a metal frame;

(b) extruding around the specified metal framework, at least one layer of the composition containing PECK, extrusion with a T-shaped head; and

(c) mounting a roof around the resulting structure;

(d) mounting one or more layers of stretch braid; and

(e) extruding an outer polymeric shell around the resulting assembly.

It is possible before step (b) to extrude one or more other layers onto a metal frame, especially a layer based on PVDF, polyamide, polyethylene, especially PE-RT, or also a material acting as a binder, to assemble the respective layers to each other.

When the pipe to be produced is a flexible smooth pipe, the process according to the invention includes the steps of:

a) extruding at least one layer of the composition containing PECK, extrusion with a T-shaped head; and

b) mounting a vault around the resulting structure;

c) mounting one or more layers of stretch braid; and

d) extruding an outer polymeric shell around the resulting assembly.

It is possible during step (a) to extrude one or more other layers, especially based on PVDF, polyamide, polyethylene, especially PE-RT, or also a material acting as a binder for assembling the respective layers to each other.

The invention is described in more detail below in non-limiting examples.

Examples

Example 1

Permeability PECK

The permeability of PECK to gases and especially to CO ₂ and H ₂ S plays a particularly important role in the oil industry, and therefore a plate of PECK (KEPSTAN® 7002, sold by ARKEMA France, ratio T:I=70:30) is prepared by injection molding with dimensions ( 100×100×2) mm. Also prepare a plate of KEPSTAN® 8002 PECK (sold by ARKEMA France, ratio T:I=80:20) with dimensions (100×100×2) mm by strip extrusion, followed by machining to the desired dimensions.

The crystallinity of PECC in the injection molding plate is characterized by measuring the enthalpy of fusion using differential scanning calorimetry (DSC). This can also be done for an extruded plate. From the obtained data, it can be determined, by comparison with the theoretical enthalpy of 100% crystallization, the degree of crystallinity of PECC in the injection molding plate and the extruded plate.

The CO ₂ permeability of the injection molded plate under stringent conditions is then evaluated by placing 90 mm diameter disks machined from the plate in a heated permeation cell (T=130°C). The same test is carried out for an extruded plate on discs with a diameter of 70 mm.

The permeation cell is supplied with a gas (in this case CO ₂ ) which enters at a certain pressure and comes into contact with one surface of the test material plate. The minimum gas capillary pressure (in this case 40 bar) can be controlled by the compressor system. On the other side of the plate, a carrier gas (in this case, nitrogen) carries the gas that permeates through the plate to a detector (in this case, a gas chromatograph (GC)), where it is quantified. The measured amount of permeate gas is used to calculate the permeability, taking into account the surface area of the plate, the difference in partial pressure of the permeant gas, the measurement time and the thickness of the plate.

The permeability is calculated in the steady state after the transition state, which reflects the time required for permeant gas molecules to diffuse through the plate. Steady state is considered to be reached when the measured CO ₂ flux does not increase by more than 1% between two samples 24 hours apart. For example, in the case of test plates, it takes a total of 10 days to complete a permeability measurement.

The results are summarized below in Table 1.

The permeability to H ₂ S of PECC was evaluated as described above for CO ₂ but using a 0.5 mm thick Kepstan® 7002 plate (machined in the form of a 70 mm diameter disk) instead of a 2 cm plate, and at a pressure of 15 bar .

The results are summarized below in Table 2.

Moreover, 50 µm thick amorphous films were prepared by extrusion calendering from KEPSTAN® 7002 PECK (sold by ARKEMA France, T:I ratio=70:30. These films were crystallized by heat treatment in an oven at 210°C for 40 minutes. 50 cm discs ² by area is extracted from two films (amorphous and crystalline) and used to measure the permeability to gases CO ₂ , O ₂ , N ₂ and CH _4. Measurements are carried out in a permeability cell as described above, but at ordinary temperature and atmospheric pressure.

The results are summarized below in Table 3.

Example 2 (comparative)

Permeability PEEK

To compare the properties of PECC with those of PEEK, Example 1 was repeated using a 2 mm thick PEEK injection molding plate (450G, sold by VICTREX).

The H ₂ S permeability was evaluated as described above for CO ₂ but using a 0.5 mm thick PEEK injection molding plate (450G, sold by VICTREX) (then machined into 70 mm disks), at a pressure of 15 bar.

The results are summarized below in tables 1 and 2.

In addition, discs with a diameter of 70 mm were cut from 50 µm PEEK 450G films obtained by extrusion calendering (amorphous extrudates and also extrudates crystallized at 205°C for more than 1 hour) and used to measure the permeability to gases CO ₂ , O ₂ , N ₂ and CH ₄ . Measurements are made in a permeability cell as described above, but at normal temperature and atmospheric pressure.

The results are summarized below in Table 3.

The results show that the CO ₂ permeability of PECK under severe temperature and pressure conditions is significantly better than that of PEEK. This observation is all the more surprising since PEEK has a higher degree of crystallinity than PECK. The reason is that the melting enthalpy of PEEK plate is higher than that of PECC plate.

Table 1 : Permeability to CO₂ Polymer Enthalpy of fusion [J/g] Temperature [°C] Pressure [bar] Permeability [cm ³ /cm sec bar] Diffusion coefficient [cm ² /sec] PECK KEPTAN® 7002 32 130 40 6.1×10 ^-9 3.6×10 ^-8 PECK KEPSTN® 8002 39 130 40 7.5×10 ^-9 4.7×10 ^-8 PEEK 450G 46 130 40 15×10 ^-9 9.5×10 ^-8

With regard to the permeability to H ₂ S, in the same way, a clear superiority was established for PECC when compared with PEEK, since the permeability of PECC, as can be seen, is 2.8 times less than the permeability of PEEK.

table 2 : Permeability to H₂S Polymer Temperature [°C] Pressure [bar] Permeability [cm ³ /cm sec bar] Diffusion coefficient [cm ² /sec] PECK ^* 130 fifteen 6.5×10 ^-9 8.0×10 ^-9 PEEK ^* 130 fifteen 1.8×10 ^-8 2.0×10 ^-8 * measured on a 0.5 mm thick plate

It has also been found that films made from crystallized PEEK are noticeably better in terms of protective properties relative to all tested gases when compared with crystallized PEEK films. Similarly, amorphous PECC films are superior in barrier properties when compared to amorphous PEEK films.

Tests have also revealed that PEEK, even in amorphous form, exhibits better barrier properties to CO ₂ , O ₂ , N ₂ and CH ₄ gases than crystallized PEEK.

Table 3: Permeability of PECC and PEEK films Polymer Crystallized/amorphous Permeability [cm ³ 50 µm/m ² 24 h atm] _{CO2 O2} N ₂ CH ₄ PECK KEPTAN® 7002 crystallized 140 80 10 7 PEEK 450G crystallized 840 180 thirty twenty PECK KEPTAN® 7002 Amorphous 645 170 ND 12 PEEK 450G Amorphous 1790 345 ND 40

These results show that, at the same thickness, the use of PECC in oil effluent pipes provides better protection of metal components against corrosion caused by the migration of gases such as CO ₂ and H ₂ S. reduce the thickness of the shells and thereby reduce the mass of the pipe.

Claims (44)

1. The use of poly(ether-ketone ketones) (PEKK) to reduce the permeability to CO ₂ and H ₂ S of a component for transporting petroleum liquids, and PEKK has a T:I ratio of 35 to 100%, where the T:I ratio is defined as a mass ratio repeating units derived from terephthalic acid (T units) of the following formula (IB): (IB)

with respect to the sum of T units and I units derived from isophthalic acid, of formula (IA) below: (IA)

. 2. Use according to claim. 1, in which poly(ether-ketone ketone) (PEKK) has a degree of crystallinity of more than 5% of the mass. 3. Use according to claim 1 or 2, wherein the poly(ether-ketone ketone) (PEKK) has a T:I ratio of 55 to 85% and more particularly 60 to 80%. 4. Use according to one of the preceding claims, wherein the permeability to CO ₂ at 130° C. is less than 10×10 ^-9 cm ³ for a thickness of 1 cm and a surface area of 1 cm ² per second and per bar of pressure of CO ₂ and/or the permeability to H ₂ S at 130°C is less than 10 ^-8 cm ³ for a thickness of 1 cm and a surface area of 1 cm ² per second and per bar of H ₂ S pressure, the amount of CO ₂ and H ₂ S being measured with a gas chromatograph (GC) respectively. 5. The use according to one of the preceding claims, wherein the component is selected from a pipe, a sheath, a sealed layer and an inner lining, especially for transporting an oil effluent. 6. A pipe for transporting an oil effluent containing a layer intended to be in contact with the oil effluent, characterized in that said layer intended to be in contact with the oil effluent contains poly(ether-ketone ketone) (PEKK), wherein PEKK has a T:I ratio of 35 to 100%, where the T:I ratio is defined as the weight ratio of repeating units derived from terephthalic acid (T units) of the following formula (IB): (IB)

with respect to the sum of T units and I units derived from isophthalic acid, of formula (IA) below: (IA)

, and has a permeability to CO ₂ at 130°C of less than 10×10 ^-9 cm ³ for a thickness of 1 cm and a surface area of 1 cm ² per second and per bar of CO ₂ pressure, and/or a permeability to H ₂ S at 130°C less than 10 ^-8 cm ³ for a thickness of 1 cm and a surface area of 1 cm ² per second and per bar of pressure H ₂ S, with the amount of CO ₂ and H ₂ S measured using a gas chromatograph (GC), respectively. 7. A pipe according to claim 6 wherein said layer intended to be in contact with the oil effluent is a sealing sheath surrounding a metal frame. 8. Pipe according to claim 6 or 7, wherein said layer intended to be in contact with the oil effluent does not contain reinforcing fibres. 9. Pipe according to one of paragraphs. 6-8, wherein said layer intended to be in contact with the oil effluent is surrounded by at least one work hardening layer. 10. Pipe according to claim 9, wherein at least one mechanical hardening layer is made of metal. 11. Pipe according to claim. 9, in which at least one layer of mechanical hardening is made of a composite material. 12. Pipe according to claim. 11, in which the composite material contains PECK and carbon fibers. 13. Pipe according to one of paragraphs. 6-12, also containing rigid metal reinforcement. 14. Pipe according to one of paragraphs. 6-13, also containing flexible metal reinforcement. 15. A method for the production or repair of a pipe according to claim 13, including the steps: a) obtaining a pipe containing poly(ether-ketone ketone) (PEKK) of the appropriate size, where PEKK has a T:I ratio of 35 to 100%, where the T:I ratio is defined as the mass ratio of repeating units derived from terephthalic acid (units T) of the following formula (IB): (IB)

with respect to the sum of T units and I units derived from isophthalic acid, of formula (IA) below: (IA)

; and b) inserting said pipe inside a metal pipe to form a lining. 16. A method for producing a pipe according to claim 14, including the steps: a) obtaining a metal frame; b) extruding around said metal frame at least one layer of a composition containing poly(ether-ketone ketone) (PEKK), extrusion with a T-shaped head, and PEKK has a ratio T:I from 35 to 100%, where the ratio T:I defined as the weight ratio of repeat units derived from terephthalic acid (T units) of formula (IB) below: (IB)

with respect to the sum of T units and I units derived from isophthalic acid, of formula (IA) below: (IA)

; and c) mounting a vault around the resulting structure; d) mounting one or more layers of stretch braid; and e) extruding an outer polymeric shell around the resulting assembly. 17. A method for producing a pipe according to claim 14, including the steps: a) extruding at least one layer of the composition containing the poly(ether-ketone ketone) PECK by T-die extrusion, where the PECK has a T:I ratio of 35 to 100%, where the T:I ratio is defined as the weight ratio of repeating units derived from terephthalic acid (T units) of formula (IB) below: (IB)

with respect to the sum of T units and I units derived from isophthalic acid, of formula (IA) below: (IA)

; and b) mounting a vault around the resulting structure; c) mounting one or more layers of stretch braid; and d) extruding an outer polymeric shell around the resulting assembly.