Corrosion monitoring of type 304 stainless steel in a black liquor evaporation process

Abstract

Type 304 stainless steel (SS) (UNS S30400) is a common material for evaporator tubes in high-temperature evaporator effects, but the composition and concentration of the black liquor can cause it to corrode. In this work, a corrosion monitoring probe was designed to study the electrochemical behavior of type 304 SS exposed to different black liquors containing descaling agents. The probe was mounted in ports at strategic points of the evaporation process. Linear polarization resistance and Tafel extrapolation techniques were used to evaluate the corrosion rates of type 304 SS electrodes in three black liquor electrolytes. This article describes the probe design, tests performed, results obtained, and limitations of the probe.