Corrosion and it’s remedy

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In simple words corrosion is defined as ruination of material because of its reaction with environment. It should be made clear here that for corrosion material does not have to be metal only and this vast term is not restricted to metals alone. On the other hand ruination of wood, rubber and paint due to exposure to sunlight is also considered to be corrosion.
Stress Corrosion Cracking (S.C.C) happens when mechanical stresses occur in the presence of corrosive environment and this phenomenon can cause serious problems. It is common observation that corrosion is always detrimental but interesting fact is that in some cases corrosion is beneficial and desirable like while anodizing of aluminum used to obtain a protective corrosion product on the surface and uniform appearance.
Chemical machining is widely used in aircraft’s industry. In this process unmasked areas are subjected to acid treatment and excess metal is dissolved. This process is adopted in situations where parts are hard and difficult to machine. Analysis of corrosion in Oil & Gas industry is of prime importance because of two main reasons:
1. To maintain continued and extended production to avoid loss of revenue.
2. To avoid catastrophic failures of facilities and avoid irreparable loss of life.
To control corrosion many industries are spending several billion dollars so one can realize the devastation caused by this phenomenon. Corrosion can be classified as either Sour or Sweet depending upon environments. Usually sour corrosion is caused due to the presence of high sulphur contents and its compounds in oil and gas industry.
Most common corrodents are:
1. Acid gases
2. Brine
3. Aggressive soils
4. Anaerobic bacteria
To control corrosion following corrosion measures may be taken:
1. Chemical Inhibition
2. Chemical Control (removal of dissolved gas)
3. PH control
4. Oxygen Scavenging
5. Cathodic Protection
6. Thickness measurement (Ultrasonic thickness meter)
7. Control of physical factors (Shocks etc)
It is important to calculate cost effectiveness of any of corrosion control measures before applying it and this can be calculated only in case of proper monitoring, the effectiveness of corrosion control program can be judged only in case of its proper monitoring.
At the end in Oil and gas industry it is difficult to total elimination of corrosion one can feel comfortably satisfied if the rate of corrosion is retarded up to safe extend.

 

References:

http://www.npl.co.uk/upload/pdf/beginners_guide_to_corrosion.pdf

http://www.npl.co.uk/upload/pdf/basics_of_corrosion_control.pdf

http://www.ce.berkeley.edu/~paulmont/241/Corrosion.pdf

About author

Muhammad Taimur

3rd year student of B.Sc Petroleum & Natural Gas Engineering at University of Engineering & Technology Lahore, Pakistan.Interested in writing research articles related to Petroleum technology and on social issues.Currently working as ambassador for YoungPetro in Pakistan, Chairman of Environmental & Science pages at Haashiya Magazine, Pakistan and President of Pakistan Career Counseling Wing.

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