Corrosion damage caused by an unreasonable design of the external wall of the storage tank

Thread Content

This post was last edited by Wang Wei2 on 2024-7-13 at 10:16. The image below shows a vault-type gasoline tank designed in accordance with **standards** at a certain refinery. The anti-corrosion material is chlorosulfonated polyethylene paint, applied in six coats, with a coating thickness of over 200 microns. The outer wall anti-corrosion coating has been in use for 5 years, and it can be seen that there is a significant difference in the degree of damage to the anti-corrosion coating on the upper part of the wind-resistant ring on the oil tank’s outer wall compared to that on the lower part. The upper coating has failed, and the tank is corroded. The condition of the coating in the lower half is much better than that in the upper half. Why? It’s fine for designers to follow national standards in their design. But problems arose after use. For the anti-corrosion coating on the outer wall of oil tanks, with the same coating material, thickness, and operating conditions, different results were observed. The reason is that the tank design features an unreasonable structure, with no rainproof ring on the tank top. When it rains, the rainwater flows down along the walls of the tank. Most of the rainwater, which contained wind-resistant rings in between, did not flow down along the tank walls. In this way, the upper part of the tank is exposed to rainwater for a longer time than the tank wall below the wind-resistant ring. Under the influence of chemical atmospheres, the anti-corrosion coating on the upper part of the tank roof deteriorates more rapidly than the anti-corrosion coating on the lower part of the tank’s wind resistance ring. Therefore, under these circumstances, it is recommended that the design department install a rainproof ring on the tops of such storage tanks, thereby addressing the issue of uneven damage to the anti-corrosion coating on the entire tank wall. It extends the service life of the anti-corrosion coating. This issue shows that sometimes there are some structural inconsistencies between our design specifications and actual applications in terms of corrosion prevention, which can lead to a shortened service life of equipment and similar items. As engineers in our corrosion prevention management, we need to pay attention to the components on the equipment that are prone to corrosion, identify the causes, carry out appropriate modifications, and thereby extend the service life of the equipment.