Crude Column Overhead Corrosion Problems Caused by Oxidized Sulfur Species

Abstract

Abstract Accelerated corrosion experienced in the overhead system of an atmospheric crude distillation column has been analyzed to determine the cause of the corrosion occurring at temperatures above the aqueous dew point. Results of field monitoring tests, laboratory tests and thermodynamic considerations all confirm that the corrosion is caused by deposition of hydrated ammonium bisulfate salts and/or condensation of sulfuric acid. This corrosion can be controlled by reducing the concentration of sulfur oxides in the system, by avoiding operating conditions conducive to formation of these corrosive species, and by selective application of resistant alloy materials.