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    • 专利摘要:
    There is a need to provide a heating device for transporting a multiphasic mixture of hydrocarbons capable of providing thermal energy for a period of up to 20 years under severe pressure and temperature conditions and making it possible to overcome an insulating external envelope thermally heavy and expensive. For this purpose, the present invention proposes a heating device for transporting a multiphase hydrocarbon mixture that is remarkable in that its at least one peripheral space (7) is permeable to water of said body of water (3). and in that the main electrical insulation layer is configured to form a water-resistant envelope around the at least one internal electrical element, said main electrical insulation layer comprising a fluorinated organic polymer. The invention also relates to the method of implementation of the device.
    公开号:FR3051241A1
    申请号:FR1600755
    申请日:2016-05-10
    公开日:2017-11-17
    发明作者:Francois Gooris；Bruno Ansart；Antoine Marret；Satishkumar Thirunavukarasu
    申请人:Technip France SAS；
    IPC主号:
    专利说明:

    HEATING DEVICE FOR TRANSPORTING A MULTIPHASIC MIXTURE OF HYDROCARBONS AND ASSOCIATED METHOD
    DESCRIPTION
    Technical field of the invention
    The present invention relates to a heating device for transporting a muKiphasic mixture of hydrocarbons comprising a structure immersed in a body of water capable of conveying said muKiphasic mixture of hydrocarbons. The invention also relates to the method of implementing said heating device for transporting said muKiphasic mixture of hydrocarbons.
    The general technical field of the invention is that of the extraction and transport of a muKiphasic mixture of hydrocarbons in the context of submarine oil and gas exploitation (so-called "subsea" in English).
    State of the art
    Multiphase hydrocarbon mixtures from oil and gas deposits are transported over several kilometers through underwater structures that can be flexible or rigid pipes within deeper and deeper water bodies. .
    The Deep Water (English) or very deep ("Ultra Deep Water") watersheds result in an increase in hydrostatic pressure of between 200 bar and 500 bar and a drop in the temperature can reach -5 ° C for example. Thus, during transport, heat exchanges with the surrounding environment cause temperature drops in the pipes and solid deposits can partially or completely obstruct the pipes.
    Indeed, the oil and gas deposits comprise a muKiphasic mixture of hydrocarbons including in particular hydrocarbons in liquid and gaseous form, water as well as solid particles, especially sand. The muKiphasic mixture of hydrocarbons may also include non-hydrocarbon gases such as nitrogen or hydrogen disulfide. In the above-mentioned high-pressure and low-temperature conditions, the water molecules in the presence of gases contained in the multiphase hydrocarbon mixture tend to form hydrates. Also, under these same conditions, the oils contained in the multiphase hydrocarbon mixture tend to form paraffin crystals. The drop in temperature is also responsible for the formation of ice blocks in the pipes leading to a slowing of the flow rate or a total cessation of production. In addition, solid deposits such as hydrates, paraffins and ice can create pressure differentials along the pipes and / or block moving elements in underwater structures, such as valves, pumps or others, and can thus causing irreversible damage to infrastructure leading to significant economic losses. Also, tragic environmental consequences may occur and the safety of operators may be compromised.
    One of the strategies to overcome these disadvantages during the transport of the multiphase mixture of hydrocarbons therefore consists in maintaining within the pipes a threshold temperature higher than the solidification temperature of paraffins, hydrates and ice under high pressure conditions.
    Initially, it was proposed to thermally insulate the pipes to minimize heat exchange between the pipe and the surrounding environment and thus to overcome a temperature drop inside the pipes. For example, it is well known in the prior art the use of pipe jackets (called "PiP" for "pipe in pipe" in English). In this type of pipe, the jacket is formed by two coaxial steel tubes. More particularly, this type of pipe comprises an inner tube in which the fluid is transported and an outer tube. Between the inner tube and the outer tube resides a completely sealed peripheral space comprising air, gas or vacuum which ensures a passive thermal insulation of the inner tube.
    However, the multiphasic mixture of hydrocarbons is transported over several kilometers. Thus, although PiP is an effective solution in terms of thermal insulation, there are still thermal losses that over long distances cause a drop in temperature allowing the formation of solid deposits as mentioned above. Passive thermal insulation is therefore not entirely satisfactory over long transport distances. Thus, structures such as PiP typically comprise at least one heating cable arranged within the peripheral space for momentarily heating or continuously heating the inner tube. This type of heating device is commonly called ETH-PiP (for "Electrically Trace Heated Pipe in Pipe" in English). An embodiment of such a heating device is shown schematically in Figure 1. The device (100) comprises in particular a pipe (500) immersed in a body of water (300) and disposed on the seabed (400). The device (100) also includes an outer tube (600) around the conduit (500) forming a peripheral space (700) around the perimeter of the conduit (500). Within this peripheral space (700) is (are) arranged (s) one or more heating cables (800) for (s) heating the pipe (500) over at least a part of its length.
    In this type of configuration, the pipe (500) and the outer tube (600) define a sealed peripheral space (700) in which the heating cables (800) are arranged. The peripheral space (700) comprises air, gas or vacuum. Thus, the heating cables (800) which are intended in particular to operate at temperatures between 20 ° C and 170 ° C over at least one cycle of 30 minutes, are preserved from the outside environment by the pipe (500) and the outer tube (600) together forming a sealed peripheral space (700).
    However, the ETH-PiP proves to be an expensive solution and the steel jacket of this heating device represents a relatively high weight which makes the installation difficult especially on great depths. In addition to the weight of ΓΕΤΗ-PiP, the steel jacket creates a particularly rigid bulky assembly difficult to manipulate by conventional means of laying. The double jacket therefore limits the laying capabilities to pipes having external diameters of about 45 cm (18 inches) or 48 cm (19 inches).
    An alternative solution is described for example in US 6, 940, 054. This document describes a heating device comprising a thermally insulated pipe commonly called ETH-SP (for "Electrically Trace Heated Single Pipe" in English). The pipe comprises an insulating external envelope that is thermally lighter than the external steel tube intended to reduce heat exchanges with the surrounding medium. This thermally insulating external envelope comprises at least one layer of polyvinyl chloride (PVC) insulators arranged around the perimeter of the pipe. The PVC insulating layer forms channels defining a peripheral space around the perimeter of the pipe. Within these channels are arranged heating means for heating the pipe. According to the document us 6, 940, 054 the heating means are in the form of tubes in which a hot fluid circulates bringing heat to the pipe. An alternative according to this prior art consists of heating means in the form of heating cables arranged within the peripheral space. Like the peripheral space of the ETH-PiP, the peripheral space of ΓΕΤΗ-SP, in particular bounded by the thermally insulating outer jacket made of PVC, and the pipe must be devoid of water. For this, the installation of this type of pipe is made using specific and complex laying means compatible with the PVC outer casing particularly fragile compared to an outer steel casing as used in a pipe of PiP type.
    Indeed, the thermally insulating outer casing PVC for example, is significantly less resistant than the ETH-PiP steel outer tube. During a conventional installation, the pipe is passed through conventional laying means, exerting clamping forces on the casing external to the pipe, such as tensioners or clamps. The clamping force applied to the pipe and in particular to the thermally insulating outer casing tends to weaken the latter. Also, the thermally insulating outer casing undergoes shocks when the pipe reaches the seabed. The pipe is therefore subjected to stresses that tend to weaken or even deteriorate the thermally insulating external envelope. As a result, cracks within this envelope may form and water from the body of water may seep into the surrounding area. The presence of water within the peripheral space deteriorates the insulating performance of the thermally insulating outer casing. Moreover, this infiltration of water poses a significant problem for the heating of the pipes by means of heating cables.
    Indeed, the conventional heating cables comprise an internal electrical element configured to generate thermal energy mainly by Joule effect when it is subjected to an electric current and an outer layer of electrical insulation. The outer layer of electrical insulation typically comprises a polymer that may be for example a crosslinked or non-crosslinked polyethylene. Under the effect of a high temperature particularly related to the temperature of the hydrocarbons at the outlet of the well, this outer layer of electrical insulation tends to degrade by thermolysis or thermo-oxidation and ultimately lose its dielectric strength properties . Also, the outer layer of electrical insulation is subjected to electric fields greater than 1 kV / m partial discharge generators and preferential paths leakage current generating a water tree (called "water tree" in English) or an electrical tree (known as "electrical tree" in English) through the insulation causing erosion or oxidation of the outer layer of electrical insulation.
    Moreover, in the presence of particularly saline water and under high pressure the hydrolysis of the outer layer of electrical insulation is all the more favored.
    In addition, the outer layer of electrical insulation generally has surface irregularities and / or defects related to the manufacturing process of this layer. These defects and irregularities are in the presence of water primers in which the water can infiltrate. Hydrolysis or water intrusion leads to the development of premature cracking of the outer layer of electrical insulation. The outer layer of electrical insulation therefore no longer performs its role of electrical insulation and the heating of the pipe is quickly no longer ensured.
    There is therefore a need to provide a heating device for transporting a light multiphasic hydrocarbon mixture, inexpensive, installable by conventional laying means, and capable of delivering thermal energy over a period of up to 20 years in a underwater environment.
    Disclosure of the invention For this purpose, the subject of the invention is a heating device for transporting a multiphase hydrocarbon mixture comprising: a structure immersed in a body of water capable of conveying a multiphasic mixture of hydrocarbons ; at least one peripheral space arranged on the periphery of said structure; at least one heating cable arranged within said at least one peripheral space comprising; at least one internal electrical element configured to generate a thermal energy when it is subjected to an electric current and at least one main layer of electrical insulation.
    The heating device for transporting a multiphase mixture of hydrocarbons is remarkable in that said at least one peripheral space is permeable to water of said body of water and in that said main layer of electrical insulation is configured to form an envelope resistant to said water around said at least one internal electrical element, said main electrical insulation layer comprising a fluorinated organic polymer.
    The devices of the prior art did not seem to be able to function after their installation by conventional laying means taking into account the presence of water within the peripheral space responsible for the degradation of the thermal insulation performances of the device. Faced with this state of affairs, a person skilled in the art would have sought to benefit from an insulating external envelope thermally resistant to shocks and forces experienced during installation in order to benefit from a sealed peripheral space and therefore from a heating device. functional. Against the technical prejudices related to the insulating performance when the peripheral space comprises water, the Applicant's work has made it possible to demonstrate that the heating device which is the subject of the invention comprises a peripheral space comprising of water was compatible with the expected insulating performance of such a device.
    Furthermore, while those skilled in the art are strongly dissuaded from using electrical cables in an environment where they could be in contact with water, the applicant's heating cables are devoid of envelopes. rigid seal leaving the main layer of electrical insulation in direct contact with seawater. Indeed, the work of the Applicant has made it possible to demonstrate that the dielectric strength properties of fluorinated organic polymers are preserved when they are in contact with water for a period of at least 20 years and when they are subjected to temperature peaks of at least 30 minutes between 20 ° C and 170 ° C. Also, while the temperature promotes the degradation of the polymeric layers under such conditions, the fluorinated organic polymers are particularly resistant when subjected to such temperatures and this even at a pressure between 10 bar and 500 bar and more particularly between 200 bar and 500 bar. Contrary to the technical prejudices related to the use of cables under these conditions, the heating cables according to the invention are compatible with the conditions of pressure, temperature, humidity and duration of use related to the operation. offshore oil.
    Thanks to the device of the present invention, it is now possible to benefit from a heating device for transporting a light, inexpensive, multiphasic hydrocarbon mixture that can be installed by conventional laying means and compatible with an underwater environment.
    Furthermore, the device according to the invention may comprise one or more of the following characteristics, taken separately or in any combination technically possible.
    According to an advantageous characteristic of the invention promoting the mechanical strength of the main layer of electrical insulation for a period of at least 20 years, especially at operating pressures of between 10 bar and 500 bar, more particularly between 200 bar and 500 bar. bar and under temperature peaks of at least 30 minutes between 20 ° C and 170 ° C and in particular between 100®C and 170®Ο, said main layer of electrical insulation has a thickness of at least 1 mm, advantageously at least 10 mm, more preferably at least 100 mm.
    According to an advantageous characteristic of the invention for improving the heating of said structure, said at least one heating cable comprises at least one additional layer.
    According to an advantageous characteristic of the invention making it possible to ensure the durability of said additional layer for a period of at least 20 years, in particular under operating pressures of between 10 bar and 500 bar, more particularly between 200 bar and 500 bar, and at temperature peaks of at least 30 minutes between 20 ° C and 170 ° C and in particular between 100 ° C and 170 ° C, said at least one additional layer comprises a fluorinated organic polymer.
    According to an advantageous characteristic of the invention allowing the homogenization of electric fields within the main layer of electrical insulation, said at least one additional layer comprises conductive particles.
    Advantageously, said at least one additional layer is disposed between said at least one internal electrical element and said main electrical insulation layer or around said main electrical insulation layer. Thus, said additional layer, in addition to the electrical functions that it can fill when it is charged with conductive particles, can advantageously enhance the mechanical strength of the main layer of electrical insulation and its cohesion with the main layer of electrical insulation. .
    The fluorinated organic polymers which are particularly suitable for attaining the object of the invention are chosen from ethylene tetrafluoroethylene (ETFE), perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE) or their mixtures .
    According to an advantageous characteristic of the invention said fluorinated organic polymer comprises a water volume recovery of less than 1%, less than 0.5% and preferably less than 0.1% according to ASTM D570. The low volume recovery of the fluorinated organic polymers in particular promotes the water resistance of the main layer.
    According to an advantageous characteristic of the invention making it possible to optimize the electrical insulation properties of the main electrical insulation layer, said main electrical insulation layer comprises at least 50% by weight of fluorinated organic polymer, preferably at least 70% by weight. % by weight of fluorinated organic polymer, preferably exclusively a fluorinated organic polymer.
    According to a particular embodiment of the invention allowing the transport of a multiphasic mixture of hydrocarbons in a light structure while being heated under conditions where the heating cable is in contact with the salt water and subjected to operating pressures between 10 bar and 500 bar, more particularly between 200 bar and 500 bar and at temperature peaks of at least 30 minutes between 20'C and 170®C and in particular between 100 ° C and 170 ° C for a period of at least 20 years, the device comprises: at least one pipe immersed in a body of water capable of conveying a multiphase mixture of hydrocarbons; a thermally insulating envelope comprising; at least one channel extending over at least a portion of the pipe; said at least one peripheral space being arranged within said at least one channel.
    Advantageously, said thermally insulating envelope comprises at least two adjacent portions forming at least one longitudinal channel.
    According to a particular embodiment of the invention for confining the heat delivered to said structure and thus to avoid heat losses leading to a decrease in the temperature of the multiphase hydrocarbon mixture, the heating device comprises: at least one pipe immersed in a body of water capable of conveying a multiphase mixture of hydrocarbons; at least one removable cover disposed opposite the pipe comprising an internal face opposite said pipe; said internal face comprises at least one channel extending over at least a part of the length of said at least one removable cover; said at least one peripheral space is arranged within said at least one channel.
    According to a particular embodiment of the invention, said structure comprises means for collecting and / or dispensing a multiphase hydrocarbon mixture.
    Thanks to the present invention, the heating cables can operate without external sealing envelope to preserve the internal electrical element of the water. The main layer of electrical fluoropolymer insulation is particularly resistant to water. The properties of the latter are preserved in contact with water and the internal electrical element remains functional under these conditions. Thus, thanks to the present invention, such a structure can now benefit from active heating for efficient circulation of a multiphase hydrocarbon mixture while being light and inexpensive. The subject of the invention is also a method for implementing the heating device for transporting a multiphasic mixture of hydrocarbons, comprising the following steps: - (a) providing a structure capable of conveying a multiphasic mixture of hydrocarbons comprising at least at least one permeable peripheral space arranged on the periphery of said structure; - (b) providing at least one heating cable in; - (b1) providing at least one internal electrical element configured to generate thermal energy when subjected to an electric current; - (b2) arranging at least one main electrical insulation layer around said at least one internal electrical element (81), said layer comprising a fluorinated organic polymer configured to form a water-resistant envelope around said at least one internal electrical element ; - (c) arranging said at least one heating cable within said at least one peripheral space; - (d) immersing said structure within a body of water.
    The methods of implementation of the heating devices according to the prior art include the provision of a steel jacket difficult to implement given its weight, its volume and the rigidity of the steel jacket and represent a major economic blow. The method according to the invention makes it possible to dispense with a steel double jacket while benefiting from active heating of the underwater structures. Now, thanks to the method of the present invention, it is possible to provide a lightweight device, inexpensive and with active heating.
    DESCRIPTION OF THE FIGURES The invention will be better understood on reading the description which follows, given solely by way of example, and with reference to the appended drawings, in which: FIG. 1 is a schematic cross-sectional view of FIG. a heating device according to the prior art, - Figure 2 is a schematic cross-sectional view of a heating device according to the invention, - Figure 3 is a schematic cross-sectional view of a heating cable equipping the device object of the invention, - Figure 4 is a schematic cross-sectional view of a heating cable equipping the device of the invention according to a first embodiment of the cable, - Figure 5 is a schematic cross-sectional view. a heating cable fitted to the device according to the invention according to a third particular embodiment of the cable, - Figure 6 is a schematic view in section tr Ansversale of a heating cable equipping the device object of the invention according to a fourth particular embodiment of the cable. FIG. 7 is a diagrammatic view in longitudinal section of an element of a heating cable equipping the device which is the subject of the invention, FIG. 8 is a schematic cross-sectional view of the heating device according to a first particular embodiment. FIG. 9 is a schematic cross-sectional view of the heating device according to a second particular embodiment of the invention; FIG. 10 is a schematic perspective view of the heating device according to a third particular embodiment of FIG. embodiment of the invention.
    Preferred embodiments of the invention
    A heating device (1) for transporting a multiphase hydrocarbon mixture according to the invention is illustrated schematically in FIG. 2 and FIGS. 8 to 10.
    The heating device (1) for transporting a multiphase hydrocarbon mixture comprises a structure (2) immersed in a body of water (3) capable of conveying a multiphase mixture of hydrocarbons.
    The structure (2) can rest for example on the bottom (4) of the body of water (3), be sowed or extend through the body of water (3) from the bottom (4) to the surface. The body of water (3) can be for example a river, a lake, a sea or an ocean. The depth of the body of water (3) is generally greater than 10 m and is for example between 200 m and 5000 m. The structure (2) can therefore be subjected to a hydrostatic pressure of at least 10 bar and more generally between 200 bar and 500 bar. The structure (2) is intended to be immersed for a period of at least 20 years. Furthermore, when the structure (2) is located in a sea or an ocean, it lies in a particularly corrosive environment given the salt content.
    Within the meaning of the present invention, the structure (2) may comprise a pipe (5) or a set of pipes (5) intended for the transport of a multiphasic hydrocarbon mixture from an underwater installation such as a well to a unit or surface installation. The unit or surface facility may be a floating production, storage and offloading unit called FPSO (Floating Production, Storage and Offloading in English) or a floating unit dedicated to liquefied natural gas called FLNG ( "Floating Liquefied Natural Gas" in English) or a single anchor tank platform called SPAR ("Single Point Anchor Tank" in English) or a semi-submersible floating unit called TLP ("Tension Leg Platform") in the English language). The pipe (5) can also extend between subsea installations. The pipe (5) can be rigid or flexible type.
    In combination or alternatively with the pipe (5), the structure (2) can comprise a means for collecting and / or distributing (11) a multiphase hydrocarbon mixture such as a manifold (called "manifold" in English language), a pump, a separator or any other equipment intended for the storage and distribution of a multiphasic hydrocarbon mixture in the offshore oil environment.
    The heating device (1) may also comprise a thermally insulating jacket (6) in order to limit the heat exchange with the surrounding medium and thus promote the heating of the structure (2), and in particular of the pipe (5). The thermally insulating casing (6) may be of the fixed type. It then comprises at least one layer of at least two adjacent insulating parts (60) arranged on the circumference of the pipe (5). Alternatively, the thermally insulating jacket (6) can be movable and be in the form of a removable cover (10) disposed along the pipe (5) or at least a part of its length.
    In addition, the oil and gas field comprises a multiphase hydrocarbon mixture comprising a gaseous phase and at least one carbonaceous liquid phase. Generally, the deposit also comprises an aqueous liquid phase and a solid phase comprising impurities such as sand or sediments. Thus, a mixture of gaseous phases, liquid phases and solid phases hereinafter generically referred to as a multiphase hydrocarbon mixture circulates inside the structure (2) at a temperature of between 60 ° C. and 200 ° C. at the well outlet and at a pressure of at least 50 bar. The structure (2) ensures the circulation of a multiphasic hydrocarbon mixture under these conditions over a period of at least 20 years. The traffic can be continuous that is to say without traffic stop over this period or momentary, that is to say with stops of traffic that can be more or less long including a few hours to several weeks.
    In addition, the heating device (1) comprises at least one peripheral space (7) arranged on the periphery of said structure (2).
    In general, the peripheral space (7) is between the outer surface of the structure (2) and a dummy envelope (70) distant a distance D from the outer surface of the structure (2) in an outer direction with respect to the structure (2). The distance D is generally between 6 cm and 100 cm, preferably between 6 cm and 15 cm.
    Said at least one peripheral space (7) is permeable to the water of the body of water (3) and thus comprises water from the body of water (3) when the heating device (1) is immersed in the body of water (3). When the body of water (3) is sea or ocean water, it comprises a salt content of between 30 g / l and 40 g / l. The peripheral space (7) is also subjected to a hydrostatic pressure of at least 10 bar, generally between 200 bar and 500 bar.
    Furthermore, the heating device (1) comprises at least one heating cable (8) arranged within said at least one peripheral space (7).
    For the purposes of the present invention, it is understood by heating cable, a medium high voltage electrical cable comprising at least one internal electrical element (81) and at least one main layer of electrical insulation (80).
    For medium voltage, high voltage is understood in the sense of the present invention a voltage across an electric cable at least greater than 1 kV. Medium voltage cables are generally configured to operate at a voltage across their terminals between 1 kV and 50 kV and the high voltage cables are typically configured to operate at a voltage across their terminals greater than 50 kV.
    More specifically, the voltage applied to the heating cable (8) depends on the distance of the structure (2) to benefit from the heating and the type of injected signal, direct current or alternating current. In this case, the heating cable (8) is subjected to a voltage across its terminals of at least 1 kV.
    Moreover, the intensity of the current flowing through the heating cable (8) is typically between 0.1 A and 320 A.
    The power consumed is generally between 50 W / m and 200 W / m.
    The heating cable (8) can be supplied with direct current or single-phase or three-phase alternating current.
    In particular, the heating cable (8) is fed by a power source located on the surface of the body of water (3) on the FPSO for example and the electric current can be transmitted to the heating cable (8) by through an umbilical. Typically, the umbilical includes, in the vicinity of the heating cable (8), a point of contact with the water of the body of water (3) making it possible to collect the leakage currents and the fault currents connected to the power source towards the power source. electrical insulation defects of the heating cable (8) generally between 1 mA / m and 10 mA / m. The point of contact is for example located at a distance of less than 500 m from the end of the heating cable (8) and may for example be an anode.
    Alternatively, the pipe (5) comprises a rising portion (called "riser" in English) extending to the installation or the surface unit. The heating cable (8) can in this case extend along this rising portion to the surface installation and can be directly connected to a power source located on the FPSO. Generally, the heating cable (8) operates during production shutdowns or during transitional phases between production shutdowns and production. The heating cable (8) can also operate when the production is in progress, that is to say during the circulation of the multiphase hydrocarbon mixture.
    As previously mentioned, and in particular shown in FIG. 3, the heating cable (8) comprises at least one internal electrical element (81) configured to generate a thermal energy when it is subjected to an electric current and at least one main layer of electrical insulation (80). The inner electrical element (81) also called "strand" comprises a set of conductive elements such as metal wires. The metal son are preferably made of alloy based on aluminum and / or copper. The outer surface of the inner electrical element (81) may also include a tin layer to preserve the integrity of the inner electrical element (81) for a period of at least 20 years.
    Typically, the internal electrical element (81) comprises an assembly of 6 to 500 wires, or even 600 wires, or even 800 wires. The number of wires is chosen in particular according to the need for flexibility of the heating cable (8) for its installation, characteristics of linear resistance and drawing capabilities. For internal electrical elements (81) of the same section, a large number of small diameter son is preferred over a small number of son of greater diameter to limit the interstices between the son and optimize the regularity and roundness the outer surface of the inner electrical element (81). Thus, the number of wires forming the inner electrical element (81) is typically greater than 100. The internal electrical element (81) can be of the simple type, segmented, compact, hollow or braided. Preferably, the internal electrical element (81) is of the compact type in order to optimize the regularity and the roundness of the internal electrical element (81).
    The degree of compactness of the inner electrical element (81) is advantageously at least 60%, preferably at least 80% and even more advantageously at least 90%. The degree of compactness is defined in particular as the ratio of sections of the wires constituting the internal electrical element (81) to the section of the circle circumscribed to the internal electrical element (81).
    The heating cable (8) is subjected to a hydrostatic pressure of between 10 bar and 500 bar and more particularly between 200 bar and 500 bar. The degree of compactness makes it possible to limit or even overcome the risks of collapse of the internal electrical element (81) under such pressures. Thus, by improving the architecture of the internal electrical element (81) and in particular its regularity and its rotundity, the pressure resistance of the internal electrical element (81) is optimized. Also, the risks of creep of the main layer (80) surrounding the inner electrical element (81) are lessened.
    Typically, the section of the inner electrical element (81) is sized to generate sufficient thermal energy primarily by Joule effect when the inner electrical element (81) is subjected to an electric current. The section of the inner electrical element (81) is for example between 0.5 mm * and 75 mm *. Such a section makes it possible in particular to generate a linear resistance of between 0.01 mOhm / m and 20 mOhm / m. Preferably, the section of the inner electrical element (81) is between 6 mm and 25 mm. The thermal energy is transferred in the form of heat to the surrounding environment and in particular to the structure (2) and through the multiphase mixture of hydrocarbons. This results in particular a melting of the solid deposits and / or a temperature rise of the multiphase hydrocarbon mixture which can be between 2 ° C, the temperature at which the ice blocks are resorbed and 65 ° C, at which temperature the paraffins are fluidified . The melting temperature of the hydrates is generally between 20 ° C. and 30 ° C. As regards the main layer of electrical insulation (80), it is in particular in contact with the water of the body of water (3). The main electrical insulation layer (80) is also subjected to the hydrostatic pressure between 10 bar and 500 bar, more particularly between 200 bar and 500 bar and at temperatures between 20 ° C and 170 ° C.
    The main electrical insulation layer (80) is configured to form a water-resistant shell around the inner electrical element (81), and comprises a fluorinated organic polymer to meet the conditions to which it is subjected.
    By fluorinated organic polymer is meant any polymer having in its chain at least one monomer chosen from compounds containing a vinyl group capable of opening to polymerize and which contains, directly attached to this vinyl group, at least one atom of fluorine, a fluoroalkyl group or a fluoroalkoxy group.
    Fluorinated organic polymers have the property of withstanding temperatures up to 170 * 0 or even 200 ° C. And unexpectedly it has been demonstrated by the Applicant that in contact with water and in these temperature conditions, the fluorinated organic polymers retain their integrity and their dielectric properties for a period of at least 20 years contrary to polymers of the prior art which tend to degrade under such conditions. The main electrical insulation layer (80) is thus a remarkable electrical insulator in that it is resistant to water. By water-resistant, it is understood that the main electrical insulation layer (80) minimizes permeation water penetration within the main electrical insulation layer (80) even at temperatures included between 20 ° C and 170 ° C and pressures between 10 bar and 500 bar, more particularly between 200 bar and 500 bar for a period of at least 20 years.
    Advantageously, the fluorinated organic polymer comprises a volume recovery of water of less than 1%, less than 0.5% and preferably less than 0.1% according to ASTM D570.
    Advantageously, the main electrical insulation layer (80) comprises at least 50% by weight of fluorinated organic polymer, preferably at least 70% by weight of fluorinated organic polymer and preferably exclusively a fluorinated organic polymer.
    Preferably, the fluorinated organic polymer is chosen from ethylene tetrafluoroethylene (ETFE), perfluoroalkoxy (FRG), fluorinated ethylene propylene (FER), polytetrafluoroethylene (RTFE) or mixtures thereof.
    The main electrical insulation layer (80) comprises when it does not exclusively comprise a fluorinated organic polymer, a mixture of fluorinated organic polymer and thermoplastic polymer such as polyethylene (RE) or polyamide (RA).
    The main electrically insulating layer (80) may comprise conventional additives such as antioxidant or anti-UV fillers or any other type of additive suitable for the intended application. However, the chemical stability of the fluorinated materials mentioned above is particularly advantageous and generally does not require additives.
    Advantageously, the main layer of electrical insulation (80) has a thickness of at least 1 mm, preferably a thickness of at least 10 mm, more preferably a thickness of at least 100 mm. The thickness of the main layer of electrical insulation (80) promotes its temperature resistance and prevents or at least minimizes the swelling and / or hydrolysis of the main layer of electrical insulation (80) in contact with water . Also, such a thickness allows the mechanical strength of the main layer of electrical insulation (80). Indeed, when the inner electrical element (81) has surface irregularities, the main layer of electrical insulation (80) has a tendency to flow within these irregularities and to no longer perform its role of electrical insulator. When the thickness of the main electrical insulation layer (80) is at least 1 mm, part of the main electrical insulation layer (80) can flow within the irregularities, the second part of the thickness having failed to provide electrical isolation of the internal electrical element (81).
    The main electrical insulation layer (80) is preferably obtained by extrusion. The extrusion and cooling rates of the main electrical insulation layer (80) are slow enough to optimize the compactness of the material and to allow for the creation of long fluorinated chains while minimizing the risk of air bubble formation in the fluorinated organic polymer. The extrusion speed (called "Melt Flow Rate" in the English language) is for example between 0.5 g / 10 min and 8 g / 10 min.
    The extrusion temperature is higher than the melting point of the fluorinated organic polymer. Generally, the extrusion temperature is between 260 ° C and 330 ° C.
    The degree of crystallinity of the fluorinated organic polymer is advantageously greater than 40%.
    The volume resistivity of the main electrical insulation layer (80) is greater than 1 GBhm per kiometer of the cable according to ASTM D257.
    In addition, the heating cable (8) may comprise an additional layer (82).
    The additional layer (82) may for example comprise a thermoplastic polymer such as polyethylene or polypropylene.
    Preferably, the additional layer (82) comprises a fluorinated organic polymer. Advantageously, the fluorinated organic polymer is chosen from the fluorinated organic polymers comprising the main electrical insulation layer (80).
    The additional layer (82) may also comprise conductive particles such as carbon black, metal particles or graphites intended to provide the semiconductor function of the additional layer (82) and thus to homogenize the electric fields around the internal electrical element (81) and thus reduce the stresses induced within the main layer of electrical insulation (80).
    Advantageously, the resistivity of the additional layer (82) comprising a fluorinated organic polymer and loaded with conductive particles is typically between 5 Ohm.cm and 50 Ohm.cm according to ASTM D257. The additional layer (82) according to the invention thus allows a better distribution of the electric fields. Generally, the thickness of the additional layer (82) is between 0.1 mm and 0.8 mm.
    In a first particular embodiment of the heating cable (8) shown in Figure 4, the additional layer (82) is disposed between the inner electrical element (81) and the main layer of electrical insulation (80).
    The additional layer (82) compensates for external surface irregularities of the inner electrical element (81). In this case, the additional layer (82) therefore has a thickness at least equal to the height of these irregularities. Generally, this thickness is between 0.2 mm and 0.4 mm.
    In a second particular embodiment of the heating cable (8) not shown, the additional layer (82) is disposed around the main layer of electrical insulation (80).
    According to this second example, the additional layer (82) ensures the transfer of electrical charges related to leakage and fault currents to the marine environment.
    According to a third particular embodiment of the heating cable (8) shown in FIG. 5, the heating cable (8) comprises two additional layers (82, 82 '), a first additional layer (82) being arranged between the electric element internal (81) and the main electrical insulation layer (80) and a second additional layer (82 ') being disposed around the main electrical insulation layer (80).
    As is well known to those skilled in the art, the heating cable (8) may comprise mechanical reinforcements (not shown) arranged around the main electrical insulation layer (80) or the additional layer (82) when the latter it is arranged around the main electrical insulation layer (80). The mechanical reinforcements may be for example metal armor to resume the axial forces experienced during the installation of the device (1).
    Preferably, and as can be seen in FIG. 2 and FIGS. 8 to 10, several heating cables (8) can be arranged on the periphery of the structure (2) in order to optimize its heating.
    Advantageously and as shown in particular in Figure 6, several heating cables (8 ', 8 ", 8'") such as those described above can be grouped in a single beam (888).
    Advantageously, at least three heating cables (8 ', 8 ", 8'") substantially aligned are grouped in a beam (888). By substantially aligned, it is understood that the center of each beam heating cable (888) is aligned along the same axis with a possible misalignment of a few millimeters. Alternatively, the heating cables (8 ', 8 ", 8'") can be arranged to form a triangular beam (888).
    More particularly, the beam (888) comprises at least one outer sheath (83) for securing the heating cables (8 ', 8 ", 8'") in a single beam (888).
    Advantageously, the outer sheath (83) is polymeric. The polymer comprises, for example, a thermoplastic such as a polyamide (PA), a polyethylene (PE) or a polyvinylidene fluoride (PVDF) or an elastomer such as an ethylene-propylene-diene monomer (EPDM). The thickness of the outer sheath (83) is generally between 0.1 mm and 5 mm.
    The outer sheath (83) comprises at least one infiltration means (86) of water of said body of water (3). Advantageously, several infiltration means (86) of water are arranged on the outer sheath length (83) every 1 m, or every 100 m or every 500 m. The infiltration means (86) are in particular arranged along the outer sheath (83) so that the water enters the interstices (84) during the installation of the device (1) without damaging said outer sheath ( 83) by erosion for example. The water infiltration means (86) may for example be a bore formed in the thickness of the outer sheath (83) as shown in FIG. 6 or any other equivalent means that is suitable for those skilled in the art passage of water through the outer sheath (83).
    The single beam bundle (888) of several heating cables (8) reduces the magnetic field coupling between the heating cables (8) and between the heating cables (8) and the structure (2). In addition, the number of heating cables (8) to be installed is reduced by three which allows them to be installed by conventional means such as a spiral. Thus, the installation of the heating cables (8) is clearly facilitated.
    Moreover, the heating cables (8) may have a length greater than 10 m, greater than 100 m, greater than 1 km or even greater than 4 km and advantageously extend over the entire length of the structure (2) or a part of the structure (2) where heating is necessary. Typically, the heating cables (8) have a length of 1.1 km corresponding to the length of a pipe section (5) (called "staik" in angianguage). Advantageously, the structure (2) may comprise several heating cables (8) arranged in series over at least a portion or over all the iongueur of the structure (2). The heating cables (8) are then reiiés via connectors (85) every 100 m, 1 km or every 4 km depending on iagueur the heating cable (8).
    A connector (85) connecting the free end of a heating cable (8a) to the free end of an adjacent heating cable (8b) is for example shown in Figure 7. It comprises in particular a male part (850) and a female portion (851) cooperating together to form the connector (85).
    Preferably, the male portion (850) has a conical surface so as to minimize potential air bubbles at the interface of the male (850) and female (851) parts. The risk of partial discharges or preferential paths of current leakage is thus limited.
    The connector (85) further comprises a means for fixing the male part (850) on the female part (851) by bolting on a flange, screwing, gluing or any fixing means known to those skilled in the art. More particularly, when it is a fastening by screwing, the means comprises a connecting ring (853) comprising on the one hand, an internal shoulder intended to engage on an outer shoulder respectively arranged on the male part. (850) and female (851) and, secondly, a tap intended to engage on a thread arranged on the female part (851) and on the male part (850), so as to constrain the male part ( 850) against the female part (851) by screwing the connection ring (853).
    Given the marine environment, a seal (852) of single or double type can be arranged between the male part (850) and female (851) to minimize the risk of water infiltration.
    Furthermore, the connector (85) comprises an electrical insulation means (857) and a means for taking up the radial forces related to the external pressure exerted on the connector (85). Thus, the connector (85) meets the same characteristics of pressure resistance, electrical insulation, and sealing as the heating cable (8).
    Thus, the connector (85) comprises a housing (854) resting against a metal clamping ring (855) arranged around the free end of the heating cable (8a, 8b). Preferably, the housing (854) is metallic and thus ensures the mechanical strength of the connector (85). The housing (854) is for example made of SS316L, Super Duplex or Inconel 825 stainless steel in order to resist corrosion.
    In addition, the electrical insulation (857) is for example a cylindrical molded part arranged within the connector (85). The electrical insulation (857) is arranged around the free end of the main electrical insulation layer (80a, 80b) of the heating cable (8a, 8b) and is in contact with the internal electrical element (81a, 81b ). Preferably, the electrically insulating top layer (857) is inserted at a conical fixing ring (859) fixed on free rextremite of the main electrical insulation layer (80a, 80b). The electrically insulating upper layer (857) is for example made of a thermoplastic material such as a polyetheretherketone (PEEK), or elastomeric such as an ethylene-propylene-diene monomer (EPDM) or an HNBR or a fluorinated thermoplastic such as PTFE or fluorocarbon elastomer (FKM).
    Advantageously, and especially when the heating cable (8) comprises an additional layer (82), the connector (85) comprises a semiconductor element (858) that can be for example a cylindrical molded part, arranged within the connector (85) .
    Preferably, the additional layer (82a, 82b) has a length at the free end of the heating cable (8) around which is arranged the semiconductor element (858). Thus, the additional layers (82a) and (82b) cooperate to facilitate the electrical connection within the connector.
    In the same manner, the free end of the inner electrical element (81a, 81b) of the heating cable (Sa, 8b) comprises one over the length of the main insulation layer (80a, 80b) thus facilitating the connection electrical connection at the connector (85).
    Furthermore, the electrical connection within the connector (85) allowing the passage of current between two sections of heating cable (8a, 8b) connected via the connector (85) can be achieved by any means known to man of the craft such as a socket or lamella connection. For example, the male (850) and female (851) parts may respectively comprise at least one electric blade (859) engaging a ring (859 ') arranged around the inner electrical element (81a, 81b) and ensuring the passage of the current by contact between the electric blades (859). Advantageously, the electric blades (859) are based on copper.
    The length of the connector (85) is preferably less than 300 mm and its thickness is preferably less than 30 mm.
    Finally, the connection between the male part (850) and the female part (851) of the connector (85) can be made on the ground (called "onshore" in English) or at sea. Other particular embodiments of the invention will now be described, given for information but not limiting.
    According to a first particular embodiment of the invention shown in FIG. 8, the structure (2) comprises a rigid pipe (5) capable of conveying a multiphase mixture of hydrocarbons.
    A rigid pipe may in particular be characterized by its minimum radius of curvature (MBR for "Minimum Bend Radius" in English). A rigid pipe typically has an MBR of the order of 8 m to 10 m. Such an MBR makes it possible to maintain the rigid pipe at an elongation threshold of less than 3%.
    The rigid pipe (5) comprises a metal tube for example of steel, stainless steel and other steel with a variable nickel content, or any other combination of these materials. Typically, the metal tube forming the rigid pipe (5) has an internal diameter of between 10 cm and 50 cm, or even higher depending on the application and a thickness of between 5 mm and 100 mm, or even higher depending on the applications.
    The rigid pipe (5) may also include an inner liner (or "liner" in English) to protect the metal tube corrosion phenomenon. For example, the inner liner may be of the corrosion resistant metal type such as an alloy of the type 316L, Super 13cr, 22 Cr duplex, alloy 28, alloy 825, alloy 2550, alloy 625 or any other alloy resistant to corrosion . Typically, the thickness of the metal coating is between 0.5 mm and 10 mm, or even greater.
    Alternatively, the inner coating may be of the polymeric type. In particular, the polymer is chosen from thermoplastics inert with respect to the multiphase mixture of hydrocarbons and resistant to temperature such as crosslinked polyethylene (PEX). Typically, the thickness of the polymeric coating is between 0.5 mm and 50 mm, or even greater.
    The rigid pipe (5) is intended to be and / or is immersed in a body of water (3). It is in contact with the water of the body of water and the metal tube is thus subjected to corrosion. Thus, to prevent corrosion of the metal tube, the rigid pipe (5) is preferably provided with an outer protective coating such as a melt bonded epoxy layer or a polypropylene layer, between 2 mm and 5 mm. Such a thickness makes it possible in particular to ensure the integrity of the protective layer up to temperatures of 130 ° C. Advantageously, a cathode-type protection means by sacrificial anode may be provided in order to improve the corrosion protection of the pipe (5).
    The heating device (1) may further comprise a thermally insulating jacket (6) disposed on the circumference of the rigid pipe (5).
    According to this first particular embodiment of the invention shown in FIG. 8, the thermally insulating envelope (6) is of the fixed type.
    More particularly, the thermally insulating jacket (6) comprises at least one layer of two adjacent portions (60), generally at least one layer of 3 adjacent portions arranged on the circumference of the rigid pipe (5). Here, a layer of 4 adjacent portions (60) is shown.
    The adjacent portions (60) comprise a thermally insulating material such as a polyolefin or a polyurethane or a mixture of insulating material. When the insulating jacket (6) comprises a superposition of layers of adjacent portions (60), they may comprise different materials depending on the layers. The insulating parts can be straight or in helices. The thickness of the adjacent portions (60) is generally between 10 mm and 90 mm. The insulating jacket (6) further comprises at least one channel extending over at least a portion of the rigid pipe (5).
    More particularly, at least two adjacent portions (60) can form at least one longitudinal channel.
    Furthermore, the insulating jacket (6) may comprise disjoint parts (61) located between the adjacent parts (60) and the rigid pipe (5). The disjoint parts (61) comprise an insulating or non-insulating material and are arranged in helices or straight lines. The disjoint portions (61) can form at least one longitudinal channel for receiving a heating cable (8).
    Around the insulating jacket (6) a holding layer (9) is wound by taping. The holding layer (9) is advantageously constituted by a non-metallic strip intended to keep the adjacent parts (60) around the rigid pipe (5). The holding layer (9) is, for example, composed of a polymer such as polyethylene comprising fibrous reinforcements of the aramid fiber or poly (p-phenyleneterephthalamide (PPD-T) type, the width of the non-metallic strip of the retaining layer (9) is generally between 50 mm and 400 mm and may include overlapping areas of a width between 0 mm and 320 mm or a superposition between 0% and 80%.
    In addition, the heating device (1) comprises a peripheral space (7) arranged on the periphery of the rigid pipe (5). The peripheral space (7) is in particular arranged within the longitudinal channel and at least one heating cable (8) according to the invention is arranged therein. The heating cable (8) is in particular wound helically within the peripheral space (7) along the rigid pipe (5). The water of the body of water (3) can diffuse through the holding layer (9) and infiltrate within the insulating envelope (6) and the peripheral space (7). The superposition zones of the non-metallic strip of the holding layer (9) participate in the inertia of the water inside the insulating envelope (6). Thus, the water is confined and the insulation of the rigid pipe (5) continues despite the diffusion of water. The heating cables (8) are in contact with the water of the body of water (8) infiltrated within the peripheral space (7). The main electrical insulation layer (80) of fluorinated organic polymer forms a sealed electrical insulating jacket around the inner electrical element (81) and thus ensures the operation of the heating cables (8) for a period of at least 20 years .
    Furthermore, the holding strip (9) and / or the thermal insulation envelope (6) may comprise flooding means that may for example be an orifice, a porous membrane or a valve opening into the space peripheral (7). More specifically, the flooding means are arranged on the thickness of the holding strip (9) every 2m and distributed around the perimeter of the structure (2) thus facilitating the flooding of the peripheral space (7).
    According to a second particular embodiment of the invention shown in FIG. 9, comprising a rigid pipe (5) immersed in a body of water (3) capable of conveying a multiphasic mixture of hydrocarbons of the type of that described in FIG. In the preceding example, the thermally insulating envelope (6) is of the mobile type. More particularly, the thermally insulating jacket (6) comprises at least one removable cover (10) arranged facing the rigid pipe (5), on at least a portion of the rigid pipe (5).
    Typically, the removable cover (10) has a thickness of between 50 mm and 100 mm.
    The removable cover (10) is adapted to allow its winding and unwinding without significant plastic deformation around a reel especially for storage on a unit or a surface platform. The removable cover (10) may be composed for example of an elastic material such as an elastomer of the rubber or polyurethane type or of syntactic foam, for example based on polypropylene with glass microspheres. Preferably, the removable cover (10) is thermally insulating. It has for example a thermal conductivity less than 0.3 W / m.K and in particular between 0.1 W / m.K and 0.3 W / m.K.
    The removable cover (10) comprises an outer face and an inner face facing the rigid pipe (5). At the inner face of the removable cover (10) is arranged at least one channel extending over at least a portion of the length of the removable cover (10). The channel extends parallel to the axis of the removable cover (10) or extends zig-zag along the removable cover (10).
    When the removable cover (10) is vis-à-vis the rigid pipe (5), the channel comprises water from the body of water (3). The channel is also subjected to the operating pressure of between 100 bar and 500 bar.
    Within the channel is arranged at least one peripheral space (7).
    Furthermore, at least one heating cable (8) according to the invention is arranged within the peripheral space (7) over part or the entire length of the cover (10). The heating cable (8) is advantageously secured to the removable cover (10). The heating cable (8) is then held in position on the removable cover (10) by means of metal rings, plastics or any other suitable means. The heating cable (8) may alternatively be mounted in the channel arranged on the inner face of the removable cover (10). The heating cable (8) is then retained in the channel by friction with or without additional fixing means. The frictional contact is in particular made by contact between the outer surface of the heating cable (8) and the side walls of the channel.
    In a third particular embodiment of the invention shown in FIG. 10, the structure (2) comprises means for collecting and / or distributing (11) a multiphase hydrocarbon mixture. The collection and / or distribution means (11) may for example be a manifold ("manifold" in English) disposed on the seabed (4).
    A manifold is a structure consisting of a set of pipes and valves that collects and dispenses a multiphasic hydrocarbon mixture from and / or to one or more flexible or rigid pipe types.
    The heating device (1) comprises a peripheral space (7) arranged on the periphery of the structure (2). The peripheral space (7) is in this case located on the outer face of the means of collection and / or distribution (11) and thus comprises water from the body of water (3). The outer face may be coated with a thermal insulation casing (6) fixed or removable type. In Fig. 10, the thermal insulation casing (6) is partially shown to simplify and clarify the figure. Advantageously, the thermal insulation envelope (6) completely covers the outer face of the collection means and / or distribution (11) to limit heat exchange with the water body (3). In the case where the invention is implemented with a thermal insulation envelope (6) of removable type, it will be preferred to use a removable cover (10) of the type previously described.
    The heating device (1) further comprises at least one heating cable (8) according to the invention which can be wound around the collection and / or distribution means (11) or arranged sinusoidally on the external face of the collection means and / or distribution (11) and maintained by rings or clamps for example.
    In the case where the invention is implemented with a thermal insulation envelope (6), it is advantageously arranged between the body of water (3) and the said at least one heating cable (8), so to reduce the thermal losses towards the body of water (3) and thus to increase the efficiency of the electric heating of the collection and / or distribution means (11). When the invention is implemented with a removable cover (10), the heating cables (8) are advantageously secured to the removable cover (10).
    A method of operating the heating device (1) for transporting a multiphase hydrocarbon mixture will now be described.
    The method comprises in particular the following steps: - (a) providing a structure (2) capable of conveying a multiphasic mixture of hydrocarbons comprising at least one water-permeable peripheral space (7) arranged around the perimeter of said structure (2 ); - (b) providing at least one heating cable (8) by: - (b1) providing at least one internal electrical element (81) configured to generate thermal energy when subjected to an electric current; - (b2) arranging at least one main electrical insulation layer (80) around said at least one internal electrical element (81), said layer comprising a fluorinated organic polymer configured to form a water-resistant envelope around said at least one an internal electrical element (81); - (c) arranging said at least one heating cable (8) within said at least one peripheral space (7); - (d) immersing said structure (2) within a body of water (3).
    In particular, the method may comprise sub-steps or additional steps as detailed below.
    In step (a), when the structure (2) comprises a rigid pipe (5) as described above, it is provided in a single section or in several sections.
    Preferably, an inner liner is formed on the inner surface of each section. For this, the inside of the rigid pipe (5) is pressurized, for example by means of a pump for injecting a fluid such as water, oil or any other suitable fluid. in order to press the inner liner against the inner surface of a section.
    In addition, in the case of a plurality of sections to be assembled, an end of a second section is placed opposite one end of a first section. Then, a junction is made between these two sections, for example by welding. Then, an outer and inner coating is made at the Junction to provide thermal insulation and corrosion resistance at the weld zone.
    When the heating device (1) comprises a thermally insulating jacket (6), a sub-step may consist in arranging a thermally insulating jacket (6) around the rigid pipe (5).
    In particular, when the thermally insulating jacket (6) is of the fixed type, it is arranged around the rigid pipe (5) during step (a).
    When the thermally insulating jacket (6) is of the movable type, more particularly a removable cover (10) it is arranged around the rigid pipe (5) in particular after the step (f) of immersion of the rigid pipe (5).
    During a step (b) at least one heating cable (8) is provided. More particularly, the heating cable (8) is provided by performing at least the sub-steps (b1) and (b2).
    During step (b1) at least one internal electrical element (81) is provided configured to generate thermal energy when subjected to an electric current. For this purpose, a set of conductive elements such as 6 to 500 wires, or even 600 wires, or even 800 wires made of alloys based on aluminum and / or copper are assembled by rolling and drawing. The inner electrical element (81) may further be of the simple, segmented, compact, hollow or braided type. Preferably, the yarns are compacted in order to obtain a degree of compactness of at least 60%, preferably of at least 80% and even more advantageously of at least 90%.
    A tin deposit may also be made on the outer surface of the inner electrical element (81).
    Then, during step (b2) is provided at least one main electrical insulation layer (80) around said at least one internal electrical element (81) comprising a fluorinated organic polymer configured to form a water-resistant envelope around said at least one internal electrical element (81).
    In a first variant, the main electrical insulation layer (80) is extruded in one or more passes so as to form a tube of thickness of at least 1 mm, at least 10 mm or at least 100 mm around. the inner electrical element (81).
    In a second variant, the main electrical insulation layer (80) is coextruded with an additional layer (82) around the inner electrical element (81). The additional layer (82) can be coextruded in the internal position, ie around the inner electrical element (81) or in the outer position, ie the main electrical insulation layer (80) is coextruded around the inner electrical element (81).
    Alternatively, each of the layers can be extruded separately. The main insulation layer (80) can be extruded at first around the inner electrical element (81). Then, in a second extrusion step, the additional layer (82) may be extruded around the main insulation layer (80). Conversely, the additional layer (82) can be extruded at first around the inner electrical element (81). Then, in a second extrusion step, the main insulation layer (80) may be extruded around the additional layer (82).
    The extrusion and cooling speeds of the main electrical insulation layer (80) are slow enough to optimize the compactness of the material and to allow the creation of long fluorinated chains while minimizing the risk of air bubbles the fluorinated organic polymer. The extrusion rate (called "Melt Flow Rate" in the English language) is for example between 0.5 g / 10 min and 8 g / 10 min.
    The extrusion temperature is higher than the melting point of the fluorinated organic polymer. Generally, the extrusion temperature is between 260 ° C and 330X.
    The degree of crystallinity of the fluorinated organic polymer is advantageously greater than 40%.
    Then during step (c) the heating cable (8) is arranged in said at least one peripheral space (7). The heating cable (8) is arranged helically or parallel to the axis of the rigid pipe (5) with the aid of a tape machine, for example. Alternatively, the heating cable (8) can be arranged within the peripheral space (7) at SZ in the following steps: - depositing said cable in a first helix portion in a direction of rotation of a predetermined angle then - depositing said cable along a second helix portion in a direction of rotation opposite to the preceding direction of a rotation angle equal to the previous angle, - repeating as many times as necessary the two previous steps.
    When several heating cables (8 ', 8 ", 8'") are grouped in a beam (888), step (b) comprises an additional sub-step (b2 ') carried out after the step (b2) of arranging an outer sheath (83) around at least two heating cables (8 ', 8 ") and preferably at least three heating cables (8', 8", 8 '").
    During step (b2 '), the outer sheath (83) is extruded around at least two heating cables (8', 8 ") and advantageously at least three heating cables (8 '8" 8' " ). Then infiltration means (86) are formed by perforation of the outer sheath (83) every 1 m, or every 100 m or every 500 m.
    When the process comprises the sub-step (b2 '), step (c) can be carried out using conventional laying means such as a spiral machine thus simplifying the installation of the heating cables (8).
    During a step (d), the structure (2) is immersed within a body of water (3) from a laying boat for example. During this step, the structure (2) and in particular the rigid pipe (5) is passed through conventional retaining means such as tensioners. The tensioners now support a pipe (5) lightened and the clamping pressure to be exerted on the pipe (5) is lower compared to that required for a PiP. In addition, the peripheral space being deliberately flooded, the absence of deterioration on the surface of the pipe (5) during handling is no longer a major factor. Indeed, for such pipes (5), a deterioration on the surface can be tolerated. The pipe (5) can therefore be more easily manipulated and placed within water bodies (3) which are deeper than the structures of the prior art.
    权利要求:
    Claims (14)
    [1" id="c-fr-0001]
    1. Heating device for transporting a multiphase hydrocarbon mixture comprising: - a structure (2) immersed in a body of water (3) capable of conveying a multiphase mixture of hydrocarbons; at least one peripheral space (7) arranged on the periphery of said structure (2): at least one heating cable (8) arranged within said at least one peripheral space (7) comprising; at least one internal electrical element (81) configured to generate a thermal energy when it is subjected to an electric current and at least one main electrical insulation layer (80) characterized in that said at least one peripheral space ( 7) is permeable to water of said body of water (3) and in that said main electrical insulating layer (80) is configured to form an envelope resistant to said water around said at least one internal electrical element ( 81), said main electrical insulation layer (80) comprising a fluorinated organic polymer.
    [2" id="c-fr-0002]
    2. Device according to claim 1 characterized in that said main layer of electrical insulation (80) has a thickness of at least 1 mm, preferably at least 10 mm, more preferably at least 100 mm.
    [3" id="c-fr-0003]
    3. Device according to any one of the preceding claims characterized in that said at least one heating cable (8) comprises at least one additional layer (82).
    [4" id="c-fr-0004]
    4. Device according to claim 3 characterized in that said at least one additional layer (82) comprises a fluorinated organic polymer.
    [5" id="c-fr-0005]
    5. Device according to one of claims 3 or 4 characterized in that said at least one additional layer (82) comprises conductive particles.
    [6" id="c-fr-0006]
    6. Device according to one of claims 3, 4 or 5 characterized in that said at least one additional layer (82) is disposed between said at least one internal electrical element (81) and said main layer of electrical insulation (80). ) or around said main electrical insulation layer (80).
    [7" id="c-fr-0007]
    7. Device according to any one of the preceding claims characterized in that said fluorinated organic polymer is selected from ethylene tetrafluoroethylene (ETFE), perfluoroaikoxy (RFA), fluorinated ethylene propylene (FER), polytetrafluoroethylene (RTFE) or their mixtures.
    [8" id="c-fr-0008]
    8. Device according to any one of the preceding claims characterized in that said fluorinated organic polymer comprises a volume recovery of water less than 1%, less than 0.5% and preferably less than 0.1% according to ASTM D570.
    [9" id="c-fr-0009]
    9. Device according to any one of the preceding claims characterized in that said main layer of electrical insulation (80) comprises at least 50% by weight of fluorinated organic polymer, preferably at least 70% by weight of fluorinated organic polymer, preferably exclusively a fluorinated organic polymer.
    [10" id="c-fr-0010]
    10. Device according to any one of the preceding claims characterized in that it comprises: - at least one pipe (5) immersed in a body of water (3) capable of conveying a multiphase mixture of hydrocarbons; a thermally insulating jacket (6) comprising - at least one channel extending over at least a portion of the pipe (5); said at least one peripheral space (7) being arranged within said at least one channel.
    [11" id="c-fr-0011]
    11. Device according to claim 10 characterized in that said thermally insulating casing (6) comprises at least two adjacent portions (60) forming at least one longitudinal channel.
    [12" id="c-fr-0012]
    12. Device according to any one of claims 1 to 9 characterized in that it comprises; - At least one pipe (5) immersed in a body of water (3) capable of conveying a multiphase mixture of hydrocarbons; - At least one removable cover (10) disposed opposite the pipe (5) comprising an inner face facing said pipe (5); said inner face comprises at least one channel extending over at least a part of the length of said at least one removable cover (10); said at least one peripheral space (7) is arranged within said at least one channel.
    [13" id="c-fr-0013]
    13. Device according to any one of the preceding claims characterized in that said structure (2) comprises at least one means (11) for collecting and / or dispensing a multiphase mixture of hydrocarbons.
    [14" id="c-fr-0014]
    14. A method of implementing the heating device for transporting a multiphase hydrocarbon mixture comprising the following steps: - (a) providing a structure (2) capable of conveying a multiphase hydrocarbon mixture comprising at least one space peripheral (7) permeable to water arranged on the periphery of said structure (2); - (b) providing at least one heating cable (8) by: - (b1) providing at least one internal electrical element (81) configured to generate thermal energy when subjected to an electric current; - (b2) arranging at least one main electrical insulation layer (80) around said at least one internal electrical element (81), said layer comprising a fluorinated organic polymer configured to form a water-resistant envelope around said at least one an internal electrical element (81); - (c) arranging said at least one heating cable (8) within said at least one peripheral space (7); - (d) immersing said structure (2) within a body of water (3).
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    同族专利:
    公开号 | 公开日
    WO2017194550A1|2017-11-16|
    AU2017261679A1|2018-11-29|
    EP3455536A1|2019-03-20|
    FR3051241B1|2018-10-12|
    BR112018073121A2|2019-03-06|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    WO2009063980A1|2007-11-15|2009-05-22|Daikin Industries, Ltd.|Fluid transfer tube with heating function and process for producing the fluid transfer tube|
    EP2520839A2|2011-05-06|2012-11-07|Evonik Degussa GmbH|Temperable pipe for offshore applications|
    DE102014005093A1|2014-01-08|2015-07-09|Voss Automotive Gmbh|Prefabricated heatable media line and method for its production|
    SG10201808916XA|2014-09-30|2018-11-29|Flexsteel Pipeline Technologies Inc|Connector for pipes|
    CA3004049C|2015-11-02|2021-06-01|Flexsteel Pipeline Technologies, Inc.|Real time integrity monitoring of on-shore pipes|
    US11208257B2|2016-06-29|2021-12-28|Trinity Bay Equipment Holdings, LLC|Pipe coil skid with side rails and method of use|
    US10753512B1|2019-03-28|2020-08-25|Trinity Bay Equipment Holdings, LLC|System and method for securing fittings to flexible pipe|
    US11242948B2|2019-11-22|2022-02-08|Trinity Bay Equipment Holdings, LLC|Potted pipe fitting systems and methods|
    US10822194B1|2019-12-19|2020-11-03|Trinity Bay Equipment Holdings, LLC|Expandable coil deployment system for drum assembly and method of using same|
    法律状态:
    2017-05-23| PLFP| Fee payment|Year of fee payment: 2 |
    2017-11-17| PLSC| Search report ready|Effective date: 20171117 |
    2018-05-29| PLFP| Fee payment|Year of fee payment: 3 |
    2019-05-23| PLFP| Fee payment|Year of fee payment: 4 |
    2020-05-25| PLFP| Fee payment|Year of fee payment: 5 |
    2021-05-31| PLFP| Fee payment|Year of fee payment: 6 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1600755A|FR3051241B1|2016-05-10|2016-05-10|HEATING DEVICE FOR TRANSPORTING A MULTIPHASIC MIXTURE OF HYDROCARBONS AND ASSOCIATED METHOD|
    FR1600755|2016-05-10|FR1600755A| FR3051241B1|2016-05-10|2016-05-10|HEATING DEVICE FOR TRANSPORTING A MULTIPHASIC MIXTURE OF HYDROCARBONS AND ASSOCIATED METHOD|
    PCT/EP2017/061080| WO2017194550A1|2016-05-10|2017-05-09|Heating device for transporting a multiphase mixture of hydrocarbons, and associated method|
    AU2017261679A| AU2017261679A1|2016-05-10|2017-05-09|Heating device for transporting a multiphase mixture of hydrocarbons, and associated method|
    EP17723062.0A| EP3455536A1|2016-05-10|2017-05-09|Heating device for transporting a multiphase mixture of hydrocarbons, and associated method|
    BR112018073121A| BR112018073121A2|2016-05-10|2017-05-09|heating device for conveying a multiphase hydrocarbon mixture and method for implementing the heating device for conveying a multiphase hydrocarbon mixture|
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