Corrosion of aboveground storage tanks containing fuels

The aboveground storage tanks (AST) at some oil refineries are in use above 50 years. Most AST containing different fuels (gasoline, kerosene, diesel oil and fuel oil) are made of carbon steel. Gasoline and kerosene tanks are furnished with floating roofs and pontoons made of carbon steel for decrease of vaporization of light fractions of hydrocarbons. Diesel oil and fuel oil tanks are equipped with fixed roofs. Corrosion mechanism and preventive measures of corrosion control of inner surfaces of AST containing different fuels are analyzed in [1-3]. The aim of this work was the calculation of corrosion rates of carbon steel shells (courses), roofs and floors of AST containing different fuels after 62-67 years of service. Outer surfaces of tanks are painted. Inner surfaces of tanks usually are not painted. Therefore corrosion occurs on inner surfaces of AST. Thicknesses of different parts of AST containing various fuels were measured and corrosion rates were calculated. These thicknesses and corrosion rates were compared with allowable minimum thicknesses and allowable maximum corrosion rates for AST. Thus, these measurements allowed deciding about the remaining life of AST, which parts of tanks should be repaired or changed, about corrosiveness of different fuels in tanks during their storage, and how often we should measure thicknesses of tanks' material. Anti-corrosion preventive measures are given at the end of this work.