Types of corrosion with diagrams,Prevention of corrosion for pipelines,commissioning and operation of pipeline.

1. Pipeline Corrosion,Commissioning
and Operations
Presented by:
J.Bhavya Sri
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2. 1.CORROSION
• Corrosion is the destructive attack of a material by
reaction with its environment.
• Besides liability issues, an important reason for
conducting a failure investigation is to identify the
mechanisms and causes of a problem to prevent
its reoccurrence.
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3. Forms of corrosion
• The different forms of corrosion represent
corrosion phenomena categorized according to
their appearance.
Group 1. Readily identifiable by ordinary visual
examination.
Group 2. May require supplementary means of
examination.
Group 3. Verification is usually required by
microscopy (optical,electron microscopy, etc.).
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4. 4

5. Uniform corrosion
Pitting corrosion
Cavitation corrosion 5

6. 6
Galvanic corrosion Intergranular corrosion

7. 7
Dealloying Exfoliation

8. Prevention of Corrosion Damage
There are basically five methods of corrosion control:
1. Change to a more suitable material
2. Modifications to the environment
3. Use of protective coatings
4. The application of cathodic or anodic protection
5. Design modifications to the system or component
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9. 2. Pipeline Commissioning and
Operations
• Flooding
• Cleaning and gauging
• Hydrotesting
• Leak tests
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10. Flooding
Cleaning and gauging
• To verify that the line is internally clean and free
from restrictions or debris and will withstand its
design pressure.
The main objectives of the flooding, cleaning, and
gauging operation are to:
1. Fill the pipeline with a suitable pressure testing
medium
2. Verify the cleanliness of the pipeline
3. Verify the pipeline integrity by gauging to make
sure no buckles or obstructions exist
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11. Hydrotesting &
Leak tests
• Conducted mainly to verify the mechanical
strength of pipeline or pipeline sections.
• Hydrotesting is carried out by pressurizing the
system to a specified internal pressure and
holding it for a certain period of time to check
whether or not there is a pressure drop.
• If the pressure drops within the hold period, it
is assumed that a leak or leaks may exist
somewhere in the system.
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12. References
• Offshore pipelines by Boyun guo,Shanhong
song,Jacob Chacko,Ali Ghalambor.
• Handbook of Corrosion Engineering by Pierre
R. Roberge.
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