Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
  • C23F13/00—Inhibiting corrosion of metals by anodic or cathodic protection
  • C23F13/02—Inhibiting corrosion of metals by anodic or cathodic protection cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions
  • C23F13/06—Constructional parts, or assemblies of cathodic-protection apparatus
  • C23F13/08—Electrodes specially adapted for inhibiting corrosion by cathodic protection; Manufacture thereof; Conducting electric current thereto
  • C23F13/18—Means for supporting electrodes
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
  • C23F2213/00—Aspects of inhibiting corrosion of metals by anodic or cathodic protection
  • C23F2213/30—Anodic or cathodic protection specially adapted for a specific object
  • C23F2213/31—Immersed structures, e.g. submarine structures

Definitions

• the present invention relates to the field of corrosion protection equipment, in particular to a cathodic protection anode for an offshore structure and to a cathodic protection device comprising it.
• Cathodic protection is a technique of "active protection” against the corrosion of a metallic material in contact with an electrolyte (an ionically conductive aqueous medium such as water, soil, concrete). It is an electrochemical prevention system based on reducing the potential of the metal to a level where the corrosion rate of the metal is significantly reduced. Cathodic protection is achieved by applying a voltage capable of delivering sufficient cathodic current to a metal surface to decrease its potential to a level corresponding to a sufficiently low residual corrosion rate for the application concerned.
• the variation in potential under the effect of current is called “polarization”.
• cathodic polarization The decrease in the corrosion potential of the metal results in a reduction in the rate of oxidation (anodic) of the metal and an increase in the reduction reaction (s) (cathodic) of the oxidizing species present in the electrolyte.
• the metal work to be protected is placed at a potential such that the corrosion rate becomes acceptable over the entire surface of the metal in contact with the electrolyte.
• a residual corrosion rate of less than 10 ⁇ m / year is generally achieved using a perfectly efficient cathodic protection system.
• a direct electric current is circulated between one or more anode (s) and the material to be protected, which constitutes the cathode.
• the effectiveness of the method requires intimate contact of the electrolyte with the material to be protected at all points thereof.
• the current, which flows through the electrolyte to the metal is adjusted so as to provide a cathodic current density allowing a potential value to be reached at which the rate of corrosion of the metal becomes very low.
• the variation in the potential of the structure as a function of the cathodic current density that it receives follows a cathodic polarization curve, or intensity - potential curve, characteristic of the electrochemical behavior of a given metal in a given electrolytic medium. This curve quantifies the current exchanges, therefore in particular the corrosion rate and the need for cathodic protection current.
• An anode by definition, is in contact with an electrolyte and seeks to transmit as much current as possible so that a structure does not corrode.
• the electrolyte is seawater
• the anodes at sea are generally always in direct contact with the external environment.
• a second solution used in a few rare cases of protection by impressed current at sea consists in using anodes based on TiMMo (Titanium - mixed metal oxides), however generally on surfaces of a few square centimeters and always in a very visible manner when the anodes are placed in the electrolyte.
• TiMMo Titanium - mixed metal oxides
• the drawbacks of the first solution are the need for many tonnes of aluminum oxide (weight, handling, installation, efficiency, etc.), as well as the dilution of these tonnes of aluminum in sea water. given that the principle of a sacrificial anode is to allow the corrosion of an anode instead of the structure to be protected, it appears clearly, in the case of protection by means of an aluminum sacrificial anode , that the aluminum consumed from the sacrificial anode will end up in seawater, which will result in a strong release of aluminum oxide in seawater.
• the drawbacks of the second solution are the small anode surface (high current density, proximity to the structure, strong local diffusion of chlorides, risk of erosion of oxidizing metals, etc.), the small distance from the structure (no more of 1 meter, in general,).
• the anodic part will therefore be protected from its deposit of oxidizing materials, during its design and assembly until it leaves the factory and especially in all stages. from the life of the anode assembly until its end of use at 5, 10, 20 or 50 years from its installation, according to the demands and the calculation of its oxidizing part. It will ensure that certain disruptors can be kept at a distance which may short-circuit it and render it inoperative.
• the invention consists in being able to have anodes having a surface, generally large, necessary according to the calculations and the design, advantageously ballasted enough to be able to lay them on the seabed or suspend them, while protecting them from direct contact with flora and fauna, various and varied attacks, such as erosion, and also own attacks linked to its own emissions of chlorides.
• the subject of the present invention is therefore a cathodic protection anode with current imposed by a rectifier for an offshore structure, characterized in that it comprises a planar anode and a cartridge comprising a peripheral frame sealed against particles of a predefined diameter of which at least one part forms a ballast, the structure of the peripheral frame being held by spacers extending in two parallel planes, the cartridge also comprising two parallel external perforated plates extending on either side of the peripheral frame, the perforated plates external being fixed to the spacers and thus defining respectively an upper face of the cartridge and a lower face of the cartridge, the upper and lower faces of the cartridge and the peripheral frame together delimiting an internal space for receiving the planar anode in the cartridge , the planar anode being configured to be electrically connected to a rectifier by means of 'at least one connection cable and having respectively an upper face facing the upper face of the cartridge and a lower face facing the underside of the cartridge, the cartridge further comprising, in the space delimited by a on the one hand
• the function of the cartridge is to enclose the planar anode in order to protect it both from possible attacks at sea, such as erosion, and possible attacks during transport of the anode.
• the ballast part or parts allow the cathodic protection anode to be placed on the seabed, or to be suspended at sea from a structure at sea.
• the structure of the cartridge is made up of two external perforated plates making it possible to filter particles beyond a certain diameter, an internal space for receiving a flat anode in the cartridge making it possible to receive the flat anode in order to limit the movements of the latter, and of spacers making it possible to maintain a certain distance between the part or parts forming ballast.
• the cartridge is then electrically connected to a rectifier for offshore structures via a connection cable.
• the cathodic protection anode has a robust and easily assembled structure.
• the cathodic protection anode is protected during its transport from the factory outlet to the offshore structures by the presence of support elements making it possible to keep the flat anode in place inside the cartridge. and thus avoiding any possible degradation of this flat anode due, for example, to shocks occurring during its transport to sea.
• the perforated plates filter particles beyond a certain diameter, thus making it possible to filter most of the particles liable to come into contact with the anode once it is at sea.
• the anodic protection anode is, because of its structure, impermeable to particles of a certain diameter.
• each connection cable electrically connecting the plane anode to a rectifier for an offshore structure is electrically insulated to prevent corrosion and a possible risk of short-circuiting.
• any shape of the sealed peripheral frame of the cartridge could be envisaged.
• the peripheral frame is rectangular.
• a peripheral frame of toroidal or even polygonal shape could be envisaged in the context of the present invention.
• the cartridge of the cathodic protection anode further comprises two internal perforated plates parallel to the external perforated plates, the two internal perforated plates being located in the internal space of the cartridge between each face of the cartridge. flat anode and the corresponding external perforated plate opposite.
• the two internal perforated plates located in the interior space of the cartridge double the effectiveness of the protection and facilitate the insertion of the planar anode into the cartridge.
• the external and internal perforated plates can have the same degree of filtering, or have different degrees of filtering.
• the internal and external perforated plates make it possible to obtain a double level of filtering. Therefore, it could be envisaged that the internal and external perforated plates each have different spacings between their perforations, different perforation diameters, a different perforation density, as well as different distribution patterns of the perforations, for example a distribution. staggered, a distribution with perforations of one plate overlapping with perforations of the other plate, a distribution in which the perforations of one plate lie behind the perforations of the other plate, or a combination of these this.
• the external perforated plates and, where appropriate the internal perforated plates are made of a material resistant to seawater, preferably polyethylene (PE).
• PE polyethylene
• the sandwich formed by the planar anode and the internal perforated plates is closed peripherally by external perforated PE plates to form a tight assembly against particles of a certain diameter.
• the electrolyte can only come into contact with the planar anode through the perforations of the internal and external PE plates.
• the cartridge further comprises, between each face of the planar anode and the facing perforated plate, one of a permeable material and a water-soluble material.
• the planar anode located in the cartridge of the anode protection anode is bagged or encapsulated with a thin layer from its design in order to protect it as soon as possible from possible shocks that may occur during its transport from the factory outlet to offshore structures.
• the planar anode is sandwiched between two layers of one of a permeable material and a water-soluble material.
• the material when the material is a water-soluble material, the latter is a non-polluting material consisting of one of a gel, cardboard, "hardboard” (registered trademark), or a combination thereof. this.
• the water-soluble material is a non-polluting material configured to disappear once the anode is installed at sea, so that the anode is protected during manufacture, transport and installation.
• a cardboard plate and / or a "hardboard” (registered trademark) plate is inserted between the flat anode and the internal perforated PE plate, to form an additional layer.
• the anode may not be covered with a water-soluble material.
• the water-soluble material covering the anode and / or the layers formed between the planar anode and the spacers serve to protect the anode during its manufacture, its transport and its installation: it is about a spacer element preventing the anode from being damaged against the PE plates.
• This spacer element is intended to disappear in contact with the electrolyte once the anode is installed.
• the planar anode is made of titanium coated with a coating based on mixed metal oxides, MMo.
• the planar anode is one of a plate, a stretched plate, a grid or a wire wound in a plane.
• the size of the cartridge forming the cathodic protection anode is reduced, thus making it possible to produce a compact cathodic protection anode.
• the peripheral frame is rectangular, at least two of the sides of said peripheral frame being constituted by ballast elements, each ballast element being formed by one of a single piece block made in a material having a density greater than that of sea water, preferably a concrete block, and a fastening device configured to be connected to an element at sea.
• each weight element is such that it allows the cartridge to be weighted and to be below sea level.
• the ends of the spacers are inserted, or even embedded, in a ballast element, for example a concrete block, thus ensuring the integrity of the anode.
• the spacers have an elongated shape, in particular in the form of a tube, and are fixed to the peripheral frame.
• the ends of the spacers can be embedded in the material constituting the ballast element.
• the support elements consist of cleats.
• the anode further comprises means for handling the assembled anode.
• the anode may have hooks, or equivalent members, to hang in the manner of a pallet, in order to allow its transport, its hooking, in particular its suspension to the structure at sea and to facilitate also its palletization and storage.
• the present invention also relates to a cathodic protection device, characterized in that it comprises a cathodic protection anode as defined above and a rectifier connected to the cathodic protection anode by at least one connection cable. .
• the cathodic protection anode as well as the rectifier for an offshore structure are envisaged within the scope of the present invention.
• FIG. 1 is a general view of a structure at sea connected to two cathodic protection anodes located at sea.
• FIG. 1 is a perspective view of the cathodic protection anode with partial cut away of each layer composing it.
• FIG. 1 is an enlarged view of one side of the anode protection anode according to the .
• the offshore structure 2 shown in comprises a mast 2a extending between a foundation 2b in the lower part and a nacelle 2c in the upper part connected to three blades 2d.
• the cathodic protection anode 1 according to a particular embodiment of the present invention is rectangular in shape.
• a cathodic protection anode 1 of toric shape or other polygonal shape could be envisaged within the framework of the present invention.
• the cathodic protection anode 1 is composed of several layers which are visible by virtue of the partial tearing shown in this Figure.
• the cathodic protection anode 1 according to a particular embodiment of the present invention comprises a cartridge 4 comprising a peripheral frame of which two parts form a ballast 5.
• the parts forming a ballast 5 of the peripheral frame each consist of a cylindrical block of. in one piece.
• a toroidal shaped ballast portion 5 extending around the cartridge 4 could be envisioned in another embodiment of the invention.
• the cartridge 4 comprises at its upper and lower faces 4a, 4b, an external perforated plate 6 comprising perforations 6a distributed over the surface of each external perforated plate 6.
• the perforations 6a of the external perforated plates 6 have a defined diameter which allows filtering particles with a diameter greater than the diameter of the perforations.
• planar anode 10 which is configured to be electrically connected to a rectifier for an offshore structure 2 by means of at least one connection cable 3, preferably a single connection cable.
• the layers of the cartridge lying respectively below the external perforated plate 6 at the level of the upper face of the cartridge 4 and above the external perforated plate 6 at the level of the lower surface of the cartridge 4 consists of spacers 7 maintaining the structure of the peripheral frame of the cartridge 4 and on which the external perforated plates 6 are fixed.
• the spacers 7 have according to a particular embodiment of the invention an elongated shape, preferably in the form of tubes spaced apart from one another and extend from one part forming a ballast 5 to another part forming a ballast 5.
• the layer located respectively immediately under the layer formed by the spacers 7 at the level of the upper face 4a of the cartridge 4 and immediately on the layer formed by the spacers 7 at the level of the lower face 4b of the cartridge 4 is composed of an internal perforated plate 8 provided at its surface with perforations 8a having a predefined diameter.
• the two internal perforated plates 8 located in the interior space 12 of the cartridge 4 make it possible to double the effectiveness of the protection and facilitate the insertion of the planar anode 10 into the cartridge 4.
• the diameter of the perforations 8a of the internal perforated plates 8 is less than the diameter of the perforations 6a of the external perforated plates 6 in order to allow a distinct degree of filtering of particles.
• the diameter of the perforations 8a of the internal perforated plates 8 may be equal or even greater than the diameter of the perforations 6a of the external perforated plates 6 in order to have a double degree of particle filtering.
• the perforations 6a of the outer perforated plates 6 and the perforations 8a of the internal perforated plates 8 are distributed in a regular pattern in which the spacing between the perforations is the same and the density of the perforations is the same.
• the distribution patterns of the perforations of the internal and external plates 8, 6 are different.
• a staggered distribution the perforations of one plate are completely offset from the perforations of the other plate
• a distribution in which the perforations of one plate overlap with perforations of the other plate the perforations of the other plate.
• one plate are partially aligned with the perforations of the other plate), a distribution in which the perforations of one plate are aligned with the perforations of the other plate (the perforations of one plate are directly aligned with the perforations of the (other plate), or a combination thereof are contemplated.
• the external perforated plates 6 and, where appropriate the internal perforated plates 8, are made of a material resistant to seawater, preferably polyethylene (PE).
• PE polyethylene
• the sandwich formed by the planar anode 10 and the internal perforated plates 8 is closed peripherally by external perforated plates 6 made of PE to form a tight assembly to particles of a predefined diameter.
• the electrolyte can only come into contact with the planar anode 10 through the perforations 6a, 8a of the inner and outer plates 6, 8 of PE.
• This layer 9 is composed of one of a water-soluble material, and a permeable material.
• the planar anode 10 located in the cartridge 4 of the anode protection anode 1 is then encapsulated with a thin layer from its design in order to protect it as soon as possible from any shocks that may occur during its transport from the outlet. from factory to offshore structures 2.
• the planar anode 10 is sandwiched between two layers 9 of one of a permeable material and a water-soluble material.
• the material when the material is a water-soluble material, the latter is a non-polluting material consisting of one of a gel, cardboard, "hardboard” (registered trademark), or a combination thereof. this.
• the water-soluble material is a non-polluting material configured to disappear once the cathodic protection anode 1 is installed at sea, so that the anode 10 is protected during its manufacture, transport and installation.
• a cardboard plate and / or a "hardboard” (registered trademark) plate is inserted between the flat anode 10 and the internal perforated plate 8, to form an additional layer.
• the anode 10 may not be covered with a water-soluble material.
• the water-soluble material covering the planar anode 10 and / or the layers formed between the planar anode 10 and the spacers 7 serves to protect the anode 10 during its manufacture, its transport and its installation: it This is a spacer element preventing the anode 10 from being damaged against the internal 8 or external 6 plates. This spacer element is intended to disappear in contact with the electrolyte once the anode 1 has been installed.
• the cartridge 4 further comprises, respectively, in the space delimited by the upper face 4a of the cartridge 4 and the upper face of the anode, and the lower face 4b of the cartridge and the lower face of the anode, two support elements 11, preferably cleats, configured to hold the planar anode 10 in a plane parallel to the upper and lower faces 4a, 4b of the cartridge 4 while remaining inside the anode. space 12 delimited by the two parallel planes of the spacers 7.
• the ends of the spacers 7 are located inside the parts forming ballast 5 of the cartridge 4, which makes it possible to guarantee the integrity of the anode 1.
• rods 13 s ' extending transversely to the spacers 7 and longitudinally with respect to the parts forming ballast 5 of the cartridge 4. These rods 13 allow the spacers 7 to be held in place during the formation of the parts forming the ballast 5 of the cartridge 4 at the level of the ends of the spacers 7.
• the planar anode 10 is a plate.
• the planar anode 10 is one of a plate, a stretched plate, a grid or a wire wound in a plane.
• the size of the cartridge forming the cathodic protection anode is reduced, thus making it possible to produce a compact cathodic protection anode.
• the anode is made of titanium coated with a coating of mixed metal oxides, MMo.
• any coating of the anode making it possible to protect the latter is envisaged within the scope of the present invention.
• the peripheral frame is rectangular, and at least two of the sides of the peripheral frame are formed by ballast elements 5.
• Each ballast element 5 consists of a single piece block made of a material having a density greater than that of sea water, preferably a concrete block.
• each ballast element 5 may consist of a fixing device configured to be connected to an offshore element 2.
• each ballast element 5 is such that it allows the anode 1 to be ballasted and to be located below sea level M.
• the anode 1 further comprises handling members 14 of the assembled cartridge.
• the anode 1 has hooks 14, or equivalent members, to hang in the manner of a pallet, in order to allow its transport, its attachment, in particular its suspension to the structure at sea. 2 and also facilitate its palletization and storage.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Prevention Of Electric Corrosion (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=69903360

Family Applications (1)

Country Status (3)

Families Citing this family (1)

Family Cites Families (13)

• 2019
  • 2019-12-04 FR FR1913737A patent/FR3104177B1/fr active Active
• 2020
  • 2020-12-02 WO PCT/IB2020/061359 patent/WO2021111314A1/fr not_active Ceased
  • 2020-12-02 EP EP20829646.7A patent/EP4069887A1/de not_active Withdrawn

Also Published As

Similar Documents

Legal Events