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Corrosion protection of buried pipelines

Date:2016-04-18

Abst: Corrosion is a leading cause of storage tank and piping failures. Corrosion-related costs for monitoring, replacing, and maintaining gathering and transmission pipelines is estimated at $7 billion annually in the U.S. alone, and another $5 billion for gas distribution.

Corrosion is a leading cause of storage tank and piping failures. Corrosion-related costs for monitoring, replacing, and maintaining gathering and transmission pipelines is estimated at $7 billion annually in the U.S. alone, and another $5 billion for gas distribution.

Corrosion protection is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell.[1] A simple method of protection connects the metal to be protected to a more easily corroded "sacrificial metal" to act as the anode. The sacrificial metal then corrodes instead of the protected metal. For structures such as long pipelines, where passive galvanic cathodic protection is not adequate, an external DC electrical power source is used to provide sufficient current.

Corrosion protection systems protect a wide range of metallic structures in various environments. Common applications are: steel water or fuel pipelines and steel storage tanks such as home water heaters; steel pier piles; ship and boat hulls; offshore oil platforms and onshore oil well casings; offshore wind farm foundations and metal reinforcement bars in concrete buildings and structures. Another common application is in galvanized steel, in which a sacrificial coating of zinc on steel parts protects them from rust.

One of the most common methods to protect buried infrastructure -- such as oil and gas transmission pipelines -- from corrosion is the application of an external coating.

Coatings and linings are applied to pipelines whether above or below ground and often are used in combination with cathodic protection. Another application that is currently getting some attention is the use of fiber-reinforced polymers to strengthen and repair pipelines.

Corrosion inhibitors are compounds which when added to the upstream pipeline can inhibit the corrosion of carbon and low-alloy steels which are commonly used because of their cost effectiveness.

Pipeline material used will also significantly influence corrosion. Using materials like plastic, stainless steel or special alloys can enhance the lifetime of the pipeline, while steel or steel reinforced concrete is subject to corrosion.

Since the implications of partially frozen ground on a pipeline's cathodic protection system weren't entirely clear, Natural Resources Canada researchers decided to explore and evaluate the use of cathodic protection in permafrost regions.

In a paper published in CORROSION journal, the researchers explain how cathodic protection systems function at low temperature and describe the various aspects of cathodic protection application in sub-zero temperatures.wlpipeline.com offer best pipelines sevice for you.