WO2018145178A1

WO2018145178A1 - Electronic protection for metal structures against corrosion

Info

Publication number: WO2018145178A1
Application number: PCT/BR2017/050201
Authority: WO
Inventors: Paulo Fernando GRACIADIO
Original assignee: Graciadio Paulo Fernando
Priority date: 2017-02-07
Filing date: 2017-07-20
Publication date: 2018-08-16

Abstract

The invention comprises an electronic anode (1) for interrupting existing corrosion processes and preventing new processes from starting in structures made of practically any metal or metal alloy, the electronic anode (1) being coupled to a metal structure (E), with the electronic current flow shown by the arrow (S). The invention is intended to provide protection against corrosion processes for structures (painted or unpainted) that are made of metals and/or metal alloys, said structures being standard (such as motor vehicles, agricultural machinery, vessels, gratings, gates and domestic appliances) or non-standard (such as miscellaneous industrial metal structures, machinery for specific uses and pipes). These structures may be exposed to different corrosive means, both natural (for example: atmospheres with salt air or sulphurous gases, salt or fresh water and soil) and man-made (for example: urban and industrial environments, contaminated soil and water).

Description

ELECTRONIC PROTECTION OF METAL STRUCTURES AGAINST

CORROSION

FIELD OF INVENTION

[0001] This patent application is for the electronic protection of metal structures against corrosion, the scope of which can be attributed to chemical and electronic engineering.

Particularly, the invention focuses on protecting against corrosive processes the structures (painted or unpainted) composed of metals and / or metal alloys, which may be of the standard type (such as motor vehicles, agricultural machinery, vessels, railings, railings, gates and appliances) or of a non-standard type (such as: various industrial metal structures, special purpose machinery and piping). These structures may be exposed to different corrosive means, both natural (eg: atmospheres with salt or sulfur gases, salt or fresh water and soils), and anthropogenic (eg urban and industrial atmospheres, soils and contaminated waters).

BACKGROUND OF THE INVENTION

Based on the electrochemical mechanism of corrosive processes it is possible to identify four generic forms of corrosion control:

• Replace the metal material: Replace the metal (or alloy) that is being corroded with one less susceptible to corrosion in the operating environment of the structure;

• Modify the structure operating medium: Modify the structure operating medium to control the nature of corrosive substances in the structure;

• Isolate the metal structure from its environment: Apply coatings to prevent corrosive substances from reaching the metal surface;

• Modify the electrochemical potential of the metal structure: Apply energy to the structure or its environment in order to energetically stabilize the atoms of the metal or alloy, reducing or nullifying their tendency to donate electrons in the medium. The choice of the most suitable anticorrosive method in each case is always based on the characteristics of the corrosive process that is taking place and, mainly, on the cost-benefit ratio of the method to be employed.

Due to the practical difficulties that normally arise when changing metal material or implementing changes in the operating environment of a structure, the most commonly used corrosion protection methods are those that seek to isolate the metal surface (painting, application of oxides). , etc.) and those aimed at modifying the electrochemical potential of the structure (cathodic or anodic protection).

The main anti-corrosion methods are discussed below.

• Barrier protection: Anticorrosive coatings are usually applied to prevent corrosive substances from reaching the metal surface. For this reason, the protection mechanism of the coatings is also called barrier protection. This coating can be a paint, oxide or metallic coating.

Industrial paint is a coating widely used mainly for the protection of metal structures subject to the corrosive action of the atmosphere;

• Cathodic Protection: If an area of the metal structure is corroded, it has an anodic electrochemical behavior in relation to its environment. Cathodic protection consists in modifying the electrochemical potential of the metal structure, shifting it to a more energy-friendly situation, ie to a cathodic electrochemical potential, in relation to the environment.

Conventional cathodic protection can be accomplished by printed current or sacrificial anode, depending on the electrical conductivity of the medium where the structure operates. In sufficiently conductive media the use of sacrificial anodes is possible, whereas in low electrical conductivity means only cathodic protection by printed current is feasible.

A typical conventional printed current cathodic protection installation requires at least three elements: rectifiers, anode bed and conductors electric; conventional cathode sacrificial anode protection eliminates the need for rectifiers.

- Problems, deficiencies and disadvantages of anti-corrosion barrier protection (coatings)

[0007] The degree and durability of the protection provided by a coating depends mainly on the quality of the coating's adhesion to the metal surface, its thickness and permeability to the corrosive elements in the medium.

Since there are no 100% impermeable coatings, in these cases the coatings act as retardants of the corrosive process, but after some time the corrosive elements eventually permeate through the protective film and the degradation process begins. In addition, painted coatings are subject to degradation due to weathering, requiring periodic maintenance.

Since painted coatings require periodic maintenance, they are used for submerged structures (vessels, floats, etc.), provided that these structures can be periodically removed from water for painting maintenance and for buried structures only in exceptional cases (due to the difficulty maintenance these structures have).

Paints also have the drawback that they are difficult to apply to structures with irregular geometry such as those with cracks, hollow parts, or hard-to-reach parts.

- Problems, shortcomings and disadvantages of conventional cathodic protection (by sacrificial anode and printed current)

Since conventional cathodic protection depends for its operation on the possibility of electrical conduction through the medium, this method does not apply to metal structures exposed to the atmosphere.

In the case of the cathodic protection by printed current it usually represents a high energy consumption, because it is necessary to overcome the resistance before providing adequate corrosion protection to the metal structure.

TECHNICAL STATE

Document BR10201201 1082 2, filed on 10/05/2012 and published on 08/04/2014, under the heading of ANTICORROSIVE PROTECTION SYSTEM THROUGH CATHODIC PROTECTION, is known from the state of the art. patent, whose purpose is to increase the life expectancy of irrigation equipment. In general, these pipes and spray tower equipment are galvanized on the outside and inside, and the outside that is exposed to the atmosphere is sufficiently protected against corrosion, however, the inside of the pipes undergo a process of corrosion. sharp corrosion. The corrosion protection system through cathodic protection consists of anodes of type ARS - 1, 3 / m, and dimensions may be used depending on the equipment to be protected. The anodes should be welded to 1/8 "rebar pieces and placed into the 1/2" PVC pipes and after preparation of the assembly, the anodes should be welded to each end of the pipe. The anti-corrosion protection system through cathodic protection allows to extend the service life of central pivots used in irrigation through the application of anti-corrosion protection characterized by the corrosion-fighting method that consists of the transformation of the structure to protect the cathode of a cell. electrochemical or electrolytic.

[0014] Document BR102012005980 0, filed on 16/03/2012 and published on 29/10/2013, under the heading ANODE FOR CATHODIC PROTECTION OF EQUIPMENT LOCATED UNDER WATER AND METHOD TO PROVIDE CORROSION PROTECTION UNDER BELOW

WATER, describes an anode for cathodic protection of underwater equipment comprising: a support body; sacrificial material retained by the support body; and securing means for releasably securing the anode to the apparatus. Therefore, recent prior art documents confirm the cited prior art.

The invention

[0016] The invention deals with a new form of corrosion protection called Electronic Anode Cathodic Protection, which also works by modifying the electrochemical potential of the metal structure to cathode values relative to its environment, as well as conventional cathodic protection techniques (eg sacrificial anode and printed current).

However, Cathode Protection by Electronic Anode, when compared to conventional cathodic protection methods (sacrificial anode and printed current), brings the following innovations:

- Provides anti-corrosion protection to metal structures subject to atmospheric corrosion, not just buried or submerged structures;

- It has much lower energy consumption than the cathodic protection method by printed current, since the application of the Electronic Anode does not depend on the conductivity of the medium;

- Simplicity of application when compared to conventional cathodic protection methods (sacrificial anode and printed current) as it does not require rectifiers and anode beds, resulting in lower installation and maintenance costs.

GREEN BACKGROUND

When compared to the barrier protection method (painted coatings), Electronic Anode Cathodic Protection presents as innovations:

- Protection also for cracks and parts of the structure where the coating cannot be applied;

- Much lower maintenance cost and longer durability, as it does not deteriorate with the effects of the weather. The present patent application has the necessary requirements to be classified as green patent, for example, in waste management, among others, and the following parameters are observed:

- Metallic corrosion in energy terms: as ore metal is in the lowest energy chemical form in relation to its environment. Therefore, in order to obtain pure metal, it is necessary to employ high amounts of energy in order to reverse the ore formation process, which nature took millennia to accomplish. This is the function of steel processing: to purify the metal and leave it in a high-energy, chemically unstable energy state, since everything in nature tends to return to the lowest possible energy level.

Therefore, in energy terms, metallic corrosion is the inverse process of the steelmaking process, since, upon corrosion, the metal makes successive chemical combinations with elements of its environment, until it returns to its ore state, returning to nature. the energy it has stored in the steelmaking process. This process of energy decay is spontaneous, since everything in nature seeks the state of least energy.

Media elements that chemically combine with metal upon their return to equilibrium are given the generic name of corrosive substances because they cause the degradation of the metal structure.

Therefore, all efforts to prevent corrosion are measures to retard the natural process of the search for energy balance, as shown in the graph.

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- Environmental Cost of Corrosion: At a meeting on corrosion held in Brussels, Belgium, in 1937, it read: "As you read this panel, 750 kg of iron is being eroded" (POURBAIX, M. "Lectures on Electrochemical Corrosion ", Plenum Press, NY, 1973, p. 2).

Therefore, an important aspect to consider with regard to anti-corrosion methods relates to the conservation of ore reserves. In view of the permanent destruction of metallic materials by corrosion, there is a need additional production of these materials to replace what has been damaged. And the replacement of these materials causes the natural reserves of some metals to tend to depletion, and in most cases transform mountainous and natural forested regions into valleys with deep depths and without vegetation.

This additional production can reach 40% of all world steel production, according to a report published by the US NBS in 1965 (Mater / a / s Protection, Vol. 6, no. 4, Apr. 1962, p. 19 NACE, Houston, Texas, USA.).

[0023] Corrosive processes occur in various sectors, such as chemical, petroleum, petrochemical, marine, construction, automotive, aeronautics, rail, telecommunications, etc.

[0024] The losses caused by corrosion can be classified into direct and indirect {VICENTE, V. "Corrosion", Editora LTC, Rio de Janeiro - RJ, 4 Edition, 2003).

Direct losses include the costs of replacing degraded parts or equipment, including the labor and energy required for such replacement, and include costs related to the operations required to prevent corrosive processes from occurring.

Indirect losses are more difficult to account for because they include often imponderable externalities, but can achieve much higher costs and environmental impacts than direct losses. Examples of indirect losses include:

- Accidental shutdowns of equipment essential to the production of a factory, such as stopping a boiler to replace a corroded pipe. In this case the production shutdown can generate financial and environmental losses much greater than the direct cost associated with pipe replacement;

- Losses of products, such as oil, solutions, gas or water, through corroded pipes until repair is made; - The loss of efficiency of equipment such as reduced heat transfer in heat exchangers due to fouling of corrosion products inside pipes; or the increased consumption of lubricating oil and fuel in automotive engines, when the rings and cylinders are corroded by flue gases, causing the loss of critical dimensions;

- Safety issues posed by localized corrosion, which can result in sudden fractures of critical parts of aircraft, trains, automobiles or bridges, causing disasters that may involve environmental aggression and loss of life;

- Environmental contamination that can result from pipeline leaks, causing pollution in seas, rivers, lakes and soils.

GREEN INNOVATION OF THE ELECTRONIC ANODE

The following are the methods of anti-corrosion protection: based on the electrochemical mechanism of corrosive processes it is possible to identify four generic ways to combat corrosion:

• Modify the electrochemical potential of the metal structure: Apply energy to the structure or its environment to energetically stabilize the atoms of the metal or alloy, reducing or nullifying their tendency to donate electrons in the medium. The choice of the most suitable anticorrosive method in each case is always based on the characteristics of the corrosive process that is taking place and, mainly, on the cost-benefit ratio of the method to be employed.

Regarding the main anti-corrosion methods, we highlight:

Industrial paint is a coating widely used mainly for the protection of metal structures subject to the corrosive action of the atmosphere.

Conventional cathodic protection can be accomplished by printed current or sacrificial anode, depending on the electrical conductivity of the medium where the structure operates. In sufficiently conductive media the use of sacrificial anodes is possible, whereas in low electrical conductivity means only cathodic protection by printed current is feasible. A typical conventional printed current cathodic protection installation requires at least three elements: rectifiers, anode bed and electrical conductors; conventional sacrificial anode cathode protection eliminates the need for rectifiers as shown in Figure 2A.

INVENTION ACCORDING TO THE GREEN JUSTIFICATION

Basically the action of the Electronic Anode consists in maintaining an excess of electrons in the metal structure to be protected. This excess of electrons basically performs three distinct functions that together contribute to significantly reduce or even nullify the speed of corrosive processes:

• The function of reducing the electrochemical potential difference between the different regions in the metal structure: A metal structure has different regions that present differences in electrochemical potential which, depending on the characteristics of the environment, may result in corrosive processes.

The excess electrons provided by the Electronic Anode contribute to leveling the electrochemical potentials of the different regions of the structure, reducing the differences between these potentials, eliminating the possibility of corrosion;

• The function of forming a protective layer on the metal surface: As the Electronic Anode maintains an excess of electrons on the metal surface, the nonmetals in the medium are attracted, stabilized and remain attached to the surface of the structure. This fact ends up forming an adherent and compact layer that passes the metal surface and substantially reduces the speed of the corrosive process;

• The function of converting pre-existing corrosion products into a protective layer: In regions of the structure where corrosive processes are already in place, pre-existing oxide layers are usually porous, soluble and poorly adherent to the metal surface. With the excess electrons provided by the Electronic Anode, these layers are gradually replaced by a passivation layer, practically paralyzing the corrosive processes already started. GENERAL DESCRIPTION OF THE INVENTION

[0032] The invention describes an Electronic Anode Cathodic Protection based on an electronic circuit, called an Electronic Anode, designed specifically to stop evolving corrosive processes and also prevent new processes from settling into structures made up of virtually any metal or alloy. Metallic

The Electronic Anode can be adapted and installed in the most different metal structures, exposed to the most corrosive means: atmospheric, buried, submerged and in the most aggressive conditions that occurs in the industrial sector.

Basically the action of the Electronic Anode consists in maintaining an excess of electrons in the metal structure to be protected. This excess of electrons basically performs three distinct functions that together contribute to significantly reduce or even nullify the speed of corrosive processes.

DESCRIPTION OF DRAWINGS

[0035] The invention will hereinafter be explained in one embodiment, and for better understanding references will be made to the accompanying drawings in which they are represented:

FIGURE 1: Overview showing the steelmaking and corrosion processes in energy terms;

FIGURE 2: Schematic drawing of conventional sacrificial anode cathodic protection;

FIGURE 3: Schematic drawing of conventional printed current cathodic protection;

FIGURE 4: Schematic drawing of cathode protection by electronic anode;

FIGURE 5: Perspective overview illustrating one embodiment of electronic anode cathodic protection. DESCRIPTION OF THE INVENTION

ELECTRONIC PROTECTION OF METAL STRUCTURES AGAINST CORROSION, the subject of this patent application, comprises an electronic anode based on an electronic circuit, called an electronic anode (1), specifically designed to paralyze evolving corrosive processes. Also prevent new processes from settling into structures made up of virtually any metal or alloy.

The electronic anode (1) can be adapted and installed in the most different metal structures (E), exposed to the most varied corrosive means: atmospheric, buried, submerged and in the most aggressive conditions that occurs in the industrial sector.

According to Figure 4, the electronic anode (1) is coupled to a metal structure (E), showing the direction of the electronic current through the arrow (S).

The action of the electronic anode (1) consists in maintaining an excess of electrons in the metal structure (E) to be protected. This excess of electrons basically performs three distinct functions that together contribute to significantly reduce or even nullify the speed of corrosive processes.

According to Figure 5, a box (1 B) houses electron-producing electronic boards, while yellow wires (2) are electron-emitting and black (3) is the earth of the electronic board. When transmitters are connected at one end of a metal alloy - yellow (2) wire - it is necessary to connect the black wire (3) at the other end of the metal alloy; Thus, it is known that the emitters are placing the electrons in the metal of the structure (E) and the black wire (3) is capturing these electrons at the other end to recycle inside the electronic plate and put it back into the metal alloy as if it were. an electron pump, using the metal frame (E) to circulate the electrons thus making the alloy protected from attack by corrosive substances from the environment.

Therefore, according to the present invention, metal alloys in general, under different circumstances of use and operations, are kept isolated from oxidation. while operating the protection; whereas structures (E) already affected by oxidation may form protective layers that prevent the intensification of the oxidation layer.

Claims

1) ELECTRONIC PROTECTION OF METAL STRUCTURES AGAINST CORROSION comprising an electronic anode based on an electronic circuit, characterized by an electronic anode (1) to paralyze evolving corrosive processes and also prevent new processes from settling into structures consisting of virtually any metal or alloy; the electronic anode (1) being coupled to a metal structure (E), with electronic current circulation shown in the arrow (S).

2) ELECTRONIC PROTECTION OF METAL STRUCTURES AGAINST CORROSION according to claim 1, characterized by a housing (1 B) housing electron-producing electronic boards, while yellow wires (2) are electron-emitting and black (3) is the earth of the electron plate.

ELECTRONIC PROTECTION OF METAL STRUCTURES AGAINST CORROSION according to claims 1 and 2, characterized in that emitters (2) are connected at one end of a metal alloy - yellow wire (2) while the black wire (3) is connected. at the other end of the alloy; In this way the emitters (2) place the electrons in the metal of the structure (E) and the black wire (3) picks up these electrons at the other end to recycle inside the electron plate and put it back into the alloy like an electron pump. , using the metal frame (E) to circulate the electrons.

ELECTRONIC PROTECTION OF METAL STRUCTURES AGAINST CORROSION according to claims 1, 2 and 3, characterized in that the electronic anode (1) maintains an excess of electrons in the metal structure (E) to be protected.