Discuss the corrosion of petrochemical storage tanks

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1. Crude oil tanks: Among all types of oil tanks, crude oil tanks suffer from more severe corrosion. Analysis of water samples from the crude oil tanks shows that corrosion is primarily caused by high levels of H2S, SO2, and Cl- in the water. 2. Semi-finished oil tanks: These tanks are also highly corrosive; the corrosion in coker crude gasoline is particularly severe. At the bottom of the tank (in the aqueous phase), uniform general corrosion and corrosion beneath scale occur. The main corrosive agents are dissolved oxygen, H2S, and inorganic salts in water. In the upper part of the gasoline tank and at the gas-liquid interface at the top, a thin layer of water forms on the tank wall surface. H2S emitted from the oil and O2 from the air dissolve in this water layer, creating highly corrosive substances, which results in uniform general corrosion in those areas, often manifesting as pitted defects. Furthermore, wet H2S has caused hydrogen-induced cracks in the welds and heat-affected zones of gas ball tanks. 3 Oil and wastewater tanks as well as gas holders are primarily subject to corrosion due to high levels of H2S, SO2, and Cl- in the water. Such equipment must have proper corrosion protection, otherwise the metal surface will corrode rapidly.