Thread Content
The service life of 316L stainless steel and duplex steel in the distillation tower is significantly different, depending on the corrosiveness of the medium, temperature, chloride ion concentration and other working conditions. 1. Typical service life of 316L stainless steel In weakly corrosive environments (such as dilute acids, dilute alkali, chlorine-containing organic solvents), the service life of 316L is generally 3-8 years. If used in distillation towers with conventional solvents such as ethanol and acetone, and the system is clean and free of free acid, it can operate stably for more than 5 years. However, in high-temperature environments containing chloride ions, pitting corrosion or stress corrosion cracking is prone to occur, and the service life may be shortened to 1-3 years, especially in the condensation area at the top of the tower or the reboiler connection. 2. The service life of duplex steel (such as S32205). In harsh environments such as high chlorine, high sulfur, and wet H₂S, the service life of duplex steel can reach 10–15 years, which is 3–5 times that of 304/316L. In the distillation tower after crude oil desalination in a coastal petrochemical plant, the dual-phase steel tower body has been running for more than 12 years under conditions containing the coexistence of Cl⁻ and H₂S and has not been replaced. In the natural gas liquids (NGL) recovery unit, the dual-phase steel feed distributor still meets the strength requirements after being used for 8 years.