Model About the Course of Corrosion Reactions of Austenitic Steels in H2S-, HCl- and CO2-Containing Atmospheres at 680 °C

Material selection for thermal cracking processes of anthropogenic resources is challenging. H2S and HCl are formed, and corrosion occurs at high temperatures. Several steels were investigated in the past. In all cases, corrosion layers were characteristically structured. On top, large chromium sulfide crystals are located, followed by a Cr2O3 layer, followed by a layer enriched in chlorine and nickel. In this paper, we propose a model on the course of the corrosion reactions. By considering the water–gas shift reaction as well as the influence of H2S, the layer formation can be explained. As an example S31400, 240 h corrosion time at 680 °C was chosen.