Corrosion in geothermal facilities: Their causes, effects, mitigation, and worldwide cases

The understanding on the characteristics of the geothermal fluids is very important in the selection of materials for fluid and heat energy extraction equipment. Dissolved CO2, H2S, NH3 and chloride ions, may corrode certain metallic materials and make them unusable. The chemical composition, temperature, and flow velocity of geothermal fluids vary, in both natural environment and the man-made conditions such as production field and power generation plant. In this paper, we resume the factors controlling different types of corrosion in high-temperature, volcanogenic geothermal fields, and evaluate the behavior of the both metallic and non-metallic materials in such environment. World-wide experience shows that precautions have to be taken in utilizing steel and stainless steels components in geothermal industry. Titanium and Inconel are preferable materials for equipment installed in high temperature, corrosive geothermal environments. In the construction side, cement, concrete polymer compounds, and fiber-reinforced plastics, and other non-metals are more useful due to their high corrosion resistance and reasonable cost. Finally, some corrosion problems in geothermal fields worldwide are presented.