Pipeline Corrosion:how To extend The service Life of Pipelines by Corrosion control

摘要

The realities of modern economics have made it critical to maximize the service life of underground pipelines. One of the key factors in any pipeline integrity management plan is the control of external corrosion. The four basic elements of a corrosion cell are: an anode, where oxidation (corrosion) occurs; a cathode, where reduction (protection) occurs; and the metallic and electrolytic pathways between them. Corrosion control can be achieved by eliminating or reducing any of these elements. For underground piping, the primary approach is to modify the electrolytic pathway by introducing a barrier between the threatened metal surface and the corrosive medium (i.e., by applying some kind of coating). If all metal surfaces could be coated with a material that was absolutely waterproof and absolutely free of flaws (holidays), all attack would be stopped. It should be noted that these two properties would have to be permanent without degradation. Unfortunately, no combination of coating materials and painstaking application can ensure a perfect coating indefinitely.