Monitoring and mitigating corrosion in geothermal systems

Abstract

AbstractIn terms of current needs for renewable resources, geothermal energy is one of the future solutions for heat and electricity generation. However, geothermal plants are exposed to very aggressive media (high‐temperature [HT], salt‐rich fluid, etc.), leading to extensive corrosion of the metallic parts. Should the corrosion inhibitors work at HT, their injection would be mandatory to ensure the reasonable lifetime of geothermal plants. The first part of this review concerns the degradations observed in geothermal plants, which depend on the site properties and the methods for evaluating the corrosion intensity of such systems. Autoclave experiments, although rarely used for geothermal applications, maybe the most appropriate to measure the representative corrosion rate, that is, under use temperature and pressure conditions. In the second part, clues to evaluate the performance and mechanism of corrosion inhibitors are mentioned, and molecules already used to protect steel are reported. However, this review also highlights the lack of data on HT inhibitors, especially for geothermal applications, where the efficiency of a given molecule is strongly related to the real medium. Thus, the protection of new geothermal plants where HT is reached requires the search for products that are stable and efficient under such conditions.