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Identifying corrosion degradation mechanisms in marine environments to prevent damage to structures and equipment

Exploration of the mechanisms of degradation of structures in marine environments and their prevention.

Published: May 22, 2023

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Introduction

Corrosion degradation mechanisms in marine environments are a constant threat to structures and equipment used in the energy sector and other industries. From oil rigs to ships to offshore wind farms, exposure to saltwater and other marine factors can cause significant and costly damage.

In this article, we will discuss the fascinating world of corrosion in marine environments and we will explore the degradation mechanisms that cause it. The different types of corrosion that can affect structures and equipment exposed to marine environments and atmospheres are exposed, and the importance of preventing these damages before they occur is discussed.

Aimed at professionals in the energy sector, students, businessmen and companies, this article aims to educate and raise awareness about the destructive effects of this mechanism. Through an informative and hands-on approach, you’ll discover the mechanisms behind corrosion and the importance of identifying them to prevent costly damage.

Entities involved in the construction and maintenance of marine structures, the operation of energy facilities or you are simply interested in understanding how corrosion affects our marine environment, this article will provide you with valuable and relevant information. A description of the factors that influence the corrosion process, the effective preventive measures will be made and we will analyze some practical cases to better understand the importance of acting proactively.

Effects of corrosion in marine environments

Degradation mechanisms by this type of corrosion can have significant detrimental effects on structures and equipment used in the energy sector and other industries. Understanding these effects is essential to highlight the importance of preventing damage and guaranteeing the integrity of marine infrastructure.

1. Weakening of structures and equipment

Corrosion in marine environments can gradually but steadily weaken structures and equipment. As metals corrode, they lose strength and may present structural failures, jeopardizing the safety and functionality of the facilities.

2. Reduction of the useful life of the infrastructures

The constant presence of salt water and exposure to marine elements accelerate the corrosion process. This can significantly reduce the lifespan of marine infrastructure, resulting in additional repair, replacement and maintenance costs.

3. Economic impact

It has a considerable economic impact. According to studies carried out by the International Association of the Steel Industry, annual losses due to corrosion in marine infrastructures can represent between 3% and 5% of the global Gross Domestic Product (GDP). This includes spending on repairs, lost productivity, and slowdown in economic development ¹

Corrosion degradation mechanisms in marine environments:

To better understand the mechanism, it is important to know the different degradation mechanisms that can occur under these conditions:

electrochemical corrosion

Electrochemical corrosion is the main degradation mechanism in marine environments. It occurs due to the interaction between metals, salt water and ions present in the marine environment. The formation of electrochemical cells of differential concentration on the surface of metals causes their gradual corrosion.

galvanic corrosion

Galvanic corrosion occurs when two dissimilar metals are in electrical contact and are submerged in a marine environment. In this process, the less noble metal (anode) corrodes more quickly, while the more noble metal (cathode) is protected. This phenomenon can accelerate the degradation of structures and equipment, especially when there is a significant difference in the potential difference between the two materials, the most active of mail and the noblest being protected.

microbiological corrosion

Microbiological corrosion is caused by the action of microorganisms, such as bacteria and algae, which form biofilms on metal surfaces. These microorganisms can produce corrosive chemicals and create local conditions conducive to corrosion, increasing the rate of degradation.

Factors influencing the marine corrosion process

Various factors influence this process; either, accelerating or mitigating its corrosive effect:

1. Composition of seawater

The composition of seawater can vary in different geographic locations and affect the rate of corrosion. For example, the concentrations of chlorides, sulfates, and other ions in seawater can influence corrosive aggressiveness.

2. Water temperature and salinity

Seawater temperature and salinity are critical factors affecting corrosion. In general, high temperatures and salinities accelerate the corrosive process, since they increase the electrical conductivity and the aggressiveness of the ions in the water.

3. Speed of water flow

The velocity of the flow of water in contact with structures and equipment also plays an important role in corrosion. Faster water flow can increase erosion and corrosion aggressiveness by promoting removal of corrosive products and providing a constant supply of oxygen.

4. Oxygen concentration

The presence of dissolved oxygen in seawater is a factor that accelerates corrosion. Oxygen promotes electrochemical reactions that corrode metals exposed to this environment.

Preventive measures to prevent corrosion in marine atmospheres

Prevention is essential to protect structures and equipment. Here are some effective measures:

Selection of corrosion resistant materials

Using corrosion resistant materials in marine environments, such as stainless steels, marine aluminum alloys, and anti-corrosion coatings, can reduce corrosive effects and extend the life of structures and equipment.

protective coatings

The application of protective coatings, such as high-quality paints and anti-corrosion coatings, creates a physical barrier between metals and the environment. These coatings may contain corrosion inhibitors to provide additional protection.

Cathodic protection

The implementation of cathodic protection systems is an effective measure to prevent corrosion. These systems divert electrical current from metals through sacrificial anodes or external current, thus protecting structures and equipment.

Regular maintenance and corrosion monitoring.

Carrying out periodic inspections, the evaluation of the system through corrosion monitoring , cleaning and proper maintenance of structures and equipment exposed to the environment is essential to identify any sign of corrosion early and address it in a timely manner. Regular maintenance includes repairing damaged coatings, cleaning surfaces, and applying additional anti-corrosion treatments as necessary.

These measures are essential to prevent costly damage, maintain structural integrity, and extend the life of structures and equipment in marine environments.

Practical cases and advances in the prevention of corrosion in saline environments

Case study: Ekofisk oil platform

The Ekofisk oil platform in the North Sea is a prominent example of success in preventing this corrosion. Comprehensive measures were implemented, such as the use of high-quality stainless steels and protective coatings, along with cathodic protection systems. These measures have proven to be effective in protecting against corrosion, prolonging the useful life of the platform and guaranteeing the safety of operations.

Innovations in materials and coatings

In the search for more effective solutions against this corrosion, advanced materials and coatings have been developed. For example, high-strength ceramic and polymer coatings have been introduced that provide increased protection against corrosion and abrasion, even in extreme marine conditions.

Notable personalities in the sector

Within the sector of the prevention of this corrosion, there are experts and prominent personalities whose contributions have been significant. Some of them include Dr. Raúl Miranda, recognized for his expertise in marine corrosion and his contributions to the investigation of new corrosion resistant materials, and Dr. Laura García, specialist in cathodic protection and leader in the development of innovative technologies for the prevention of corrosion.

Advances in corrosion monitoring and predictive maintenance

The implementation of real-time monitoring systems and predictive maintenance has allowed early detection of this corrosion. Through the use of advanced monitoring technologies and sensors, it is possible to assess corrosion in real time and take preventive action before significant damage occurs. This has contributed to the optimization of maintenance programs and the reduction of costs associated with corrosion.

Conclusion

Corrosion degradation mechanisms in marine environments have detrimental effects on structures and equipment used in the energy sector. Knowing the degradation mechanisms, the influencing factors and applying adequate preventive measures are essential to guarantee the integrity and durability of these infrastructures. Advances in materials, coatings, cathodic protection, and monitoring techniques continue to drive the prevention of this degradation mechanism, ensuring the efficiency, safety, and sustainability of operations in different industrial sectors.