Corrosion of air storage tank
Thread Content
A gas storage tank belonging to a certain company was put into use in 2010. The first inspection in 2013 revealed no defects exceeding acceptable limits. During an inspection in March 2018, severe corrosion was found on the lower end cap, as shown in the image. After grinding away the corroded areas, thickness measurements were taken; the original wall thickness of the end cap was 6 mm, but it now only amounts to 2.7 mm. Operating conditions: Operating pressure of 0.7 MPa, operating temperature < 50°C, continuous operation, with a 7-day shutdown during the Spring Festival each year. The user of the gas storage tank is a steel structure factory (without the corrosive environment of a chemical plant), and the location where the tank is installed is relatively humid. I would like to ask the experts: why did no corrosion occur in the first 3 years, but corrosion became so severe in the following 5 years? What is the mechanism behind this corrosion?
It is likely that the anti-corrosion coating has failed, resulting in corrosion in a humid environment.
A composite tank with fiberglass lining can be used
Should it be scrapped or kept in use? High-molecular reinforcement materials can be used for reinforcement and corrosion protection, which can **extend the service life!**
The oil and gas inside the air compressor contain sulfides, which has caused corrosion in your air storage tank. It is recommended to replace it with a stainless steel tank, or to apply an aluminum coating to its interior; this will prevent corrosion in the equipment over a period of 15 years.
With such severe corrosion, from the perspective of equipment safety, it should be scrapped and discarded; in the event of a safety incident, the consequences would be too severe!