1. Bottom of the inner wall of the tank (aqueous phase zone)
● The corrosion inside the fuel storage tank is more complicated. The tank bottom area and the bottom tank wall have a large contact with the oil-splitting water. The bottom of the storage tank will be corroded by different stages of oil-splitting water. Due to the different types of oil, the oil-splitting water may be acidic or alkaline.
● The corrosive action of the precipitated water causes the steel of the oil storage tank to be seriously damaged, so that there are large and small ulcer-like pits, and in serious cases, it is possible to form a perforation of the tank wall, thereby causing oil leakage. Therefore, the inner wall of the bottom of the tank is the most corrosive part.
★ Coating selection:
The inner wall of the crude oil storage tank bottom plate and the oil moisture boundary shall be insulated and anti-corrosive coating; It is chosen to shield the coating with very good permeability resistance to prevent the penetration of the medium in the tank to cause corrosion under the coating
2. Tank wall area (oil phase zone)
● The tank wall of the tank is directly in contact with the oil. The oil contains water or other kinds of electrolytes such as acid or alkali salts, which leads to electrochemical corrosion, especially the tank wall which is in contact with the interface between oil, water and oil. Corrosion in the tank wall area is less corrosive than the bottom wall of the inner wall because the corrosion shows a uniform small point.
★ Coating selection:
The choice of conductive coating can effectively prevent the accumulation of static electricity, thus ensuring the safety of the oil to a large extent. Eliminate safety hazards caused by static electricity. It is necessary to choose materials that are not damaged by steel to prevent the paint from corroding the steel. The selected coating should also ensure that the quality of the oil is not damaged and does not pollute the oil.
3. Tank top area
●Although the tank top of the tank will not directly contact the oil, it will be severely corroded by oxygen vapor and hydrogen sulfide. The degree of corrosion is more serious than the tank wall area, but it is less corrosive than the bottom of the tank.
★ Coating selection:
The choice of conductive coating can effectively prevent the accumulation of static electricity, thus ensuring the safety of the oil to a large extent. Eliminate safety hazards caused by static electricity. The selected coating should also ensure that the quality of the oil is not damaged and does not pollute the oil.
4. Tank outer wall (tank wall and tank top outer wall)
● Corrosion of the outer wall of the tank depends on the environment in which the tank is located. The more severe the environment is corroded by outdoor sunlight, the more serious the corrosion of the tank.
● If the tank is at the beach, it will be corroded by the sea atmosphere of the sea. If it is in the oil storage tank of the refinery, there will be corrosion of the chemical atmosphere.
★ Coating selection:
Generally, the outer wall primer should have excellent anti-rust properties. It is most common to choose zinc-rich primer as the bottom layer of the composite system, and mica or flake coating as the middle layer, using acrylic topcoat or acrylic polyurethane topcoat as the top layer. Some of the insulation coatings are now used as the top layer of the tank.
www.autorecyclingchina.com