During the pre-commissioning of new pipelines, a lot of energy is often put into testing, cleaning and drying. If the pipeline is not directly put into service (commissioning) and if no other protective measures have been taken (cathodic protection, coating, etc.), all the work may have been in vain. This is because oxygenated air and moisture can corrode iron pipelines. The same applies to pipelines that are taken out of service for a longer period of time. TECCURO has several options to slow down this corrosion process.
“WE CARE ABOUT YOUR PIPELINES”
By flushing the pipeline with nitrogen, the oxygen percentage (21%) is reduced. The less oxygen is present, the slower the corrosion process is. To prevent fresh outside air from entering the pipeline, the pipeline is set down at a small nitrogen overpressure usually between 0,5 and 2 bar. The advantage of nitrogen is that it:
- is easy to obtain and inject;
- is inert and therefore hardly reacts with other substances;
- has a low dew point.
Depending on the product that enters the line during commissioning, nitrogen has the advantage of being inert. Nitrogen does not react with flammable hydrocarbons such as ethylene, petrol, kerosene, etc. By using nitrogen as a safety buffer, the pipeline can be filled without problems. So not only does nitrogen slow down corrosion, it also generates a safe situation to start up your pipeline.
Despite the several options that TECCURO has to pig non-piggable pipelines, there will be always pipelines which cannot be pigged. These pipes could be pneumatically tested, but that strongly depends on the risks, restrictive measures and legislation. This can lead to situations where a pipeline has to be tested with water and that the water cannot be removed or only very slowly. Untreated water can trigger the corrosion process. For these situations but also as an extra protection in piggable pipelines, TECCURO can apply special treated water. The water is low in oxygen and the added chemicals ensures that a thin protective layer is formed on the pipeline wall that limits the formation of corrosion.