Inhibitor Influence on Corrosion of Carbon Steel with Respect to the Upper Rhine Graben Geothermal Brines

Corrosion of construction materials in geothermal brine environments is of great concern in the long-term operation of geothermal power plants. In case of geothermal energy production there are many site-specific factors influencing corrosion processes e.g. high salinity, pH, high temperature, presence of non-condensable gases, fluid velocity, corrosion products, geometry of the power plant, acid treatment and acid cleaning procedures (Guerra & Jacobo 2012). To prolongate the lifetime and thus decrease downtime periods and economic losses, a careful material selection at acceptable costs is essential (Carter & Cramer 1992). Nogara & Zarrouk (2018b) summarized the results of 172 tested metals and alloys for the use in geothermal environment. Among low cost carbon steels, stainless steels, alloys and titanium are employed for functional parts as turbine blade or heat exchanger material respectively (e.g. Ravier et al. 2016). In geothermal power plants up to 12 types of corrosion may occur depending on the corrosiveness of the produced brine (e.g. Nogara & Zarrouk 2018a).