Influence of elemental sulphur on corrosion of carbon steel in geothermal environments

Severe damage from corrosion has occurred on the carbon steel pipelines of noise reduction equipment used in the high pressure regulation system at Cerro Prieto II (CPII) geothermal power plant. The problem was characterized by standard techniques of surface and chemical analyses performed on various materials: corrosion products, rocks and carbon steels which were components of the failed structure, it was found that the major species that promotes the corrosion process in wet conditions and temperatures higher than 180 °C were elemental sulphur (S ), hydrogen sulphide (H 2S), oxygen (O 2) and chlorides (Cl -). Thus, based on the results obtained, a scheme of several reactions was proposed as the potential mechanism of the corrosion promoted by elemental sulphur on carbon steel in the geothermal environment