Storage tanks ensure a steady supply of liquids and gases for manufacturing processes and commercial use. While these tanks may appear robust on the outside, a hidden danger lies within Microbiologically Influenced Corrosion (MIC). This insidious form of corrosion is caused by microbial activity and can silently deteriorate tank walls, leading to leaks, product contamination, and potentially catastrophic failures. In this blog, we will delve into the world of MIC corrosion in storage tanks, exploring its invisible dangers and the importance of early detection and preventive measures.
Corrosion caused by microorganisms (MIC) – AMPP
Microbiologically influenced corrosion, or MIC, can be brought on by microorganisms, including bacteria, fungi, and microalgae. Even though they don’t cause a particular kind of corrosion, they can speed up the process or cause the mechanisms of corrosion to change.
The deterioration of petroleum product pipelines and storage tanks is a well-known phenomenon called MIC. Many oil pipelines experience severe corrosion and microfouling issues, which have an impact on the operation and maintenance expenses of the pipelines.
When a metal reacts with something else, such as oxygen, hydrogen, an electrical current, or even dirt and germs, it corrodes. When metals like steel are subjected to excessive strain, which causes the substance to split, corrosion can also occur.
Understanding Microbiologically Influenced Corrosion (MIC)
MIC is a type of corrosion driven by microorganisms that thrive in the tank’s environment. These microbes create a biofilm on the inner tank surfaces, providing a conducive environment for corrosive reactions to occur. MIC is particularly concerning because it can occur in both aerobic (oxygen-rich) and anaerobic (low-oxygen) conditions, making it challenging to detect and prevent.
The Invisible Dangers of MIC Corrosion
The presence of MIC in storage tanks poses a range of invisible dangers that can have severe consequences:
a. Hidden Damage: Unlike other forms of corrosion that create visible signs of rust or degradation, MIC corrosion occurs beneath the biofilm, making it difficult to detect with the naked eye until significant damage has already occurred.
b. Structural Compromise: As MIC progresses, it weakens the tank’s walls, leading to potential leaks, spills, and even catastrophic failures, risking the safety of personnel and the environment.
c. Product Contamination: The biofilm and byproducts of MIC can contaminate the stored product, compromising its quality and safety.
d. Increased Maintenance Costs: Repairing MIC-related damage can be costly, leading to increased maintenance expenses for industries.
e. Legal and Regulatory Compliance: MIC-induced tank failures may result in legal liabilities and non-compliance with environmental and safety regulations.
Factors Contributing to MIC Corrosion
MIC is influenced by various factors that create favorable conditions for microbial growth and corrosion:
a. Moisture and Nutrients: The presence of water and nutrients in the tank environment provides an ideal breeding ground for microbes.
b. Microbial Activity: Certain bacteria and archaea species are particularly aggressive in causing corrosion.
c. Temperature: Elevated temperatures can accelerate microbial activity, exacerbating MIC.
d. Material Composition: The type of metal used in the tank construction can affect its susceptibility to MIC.
Detecting and Preventing MIC Corrosion
Early detection and preventive measures are vital in combating MIC corrosion in storage tanks:
a. Regular Inspections: Implement a comprehensive inspection program to identify early signs of MIC corrosion. Advanced non-destructive testing methods can help detect hidden corrosion beneath biofilms.
b. Biocide Treatments: Controlled and appropriate use of biocides can help mitigate microbial growth and reduce the chances of MIC.
c. Material Selection: Opt for corrosion-resistant materials during tank construction to minimize the risk of MIC.
d. Cathodic Protection: Implement cathodic protection systems to safeguard the tank’s metal surfaces from corrosive reactions.
e. Proper Cleaning and Maintenance: Maintain tanks in good condition by adhering to regular cleaning and maintenance schedules, removing biofilms and reducing microbial activity.
f. Monitoring and Control: Employing real-time monitoring systems can help track changes in tank conditions and detect potential MIC-related anomalies.
Collaborative Efforts and Industry Best Practices
To effectively combat MIC corrosion, industry stakeholders must collaborate and share best practices. Organizations like the American Petroleum Institute (API) and the National Association of Corrosion Engineers (NACE) offer guidelines and standards for managing MIC and corrosion-related issues.
MIC corrosion poses an invisible but formidable threat to storage tanks in various industries. Understanding the nature of this insidious corrosion, its dangers, and the factors contributing to its occurrence is vital for safeguarding storage tanks, the stored products, and the environment. By implementing proactive detection methods, and preventive measures, and adhering to industry best practices, industries can mitigate the risks of MIC corrosion and ensure the integrity and longevity of their critical storage assets.
