Monday, February 4, 2019

Science & Technology: Using Titanium to Control Excessive Corrosion in Extreme Geothermal Conditions

Testing Corrosion-Resistant Alloys for Use in Geothermal Power Plants (Materials Performance)

According to NACE International (National Association of Corrosion Engineers) members W.D. MacDonald and J.S. Grauman with Titanium Metals Corp. (Exton, Pennsylvania, USA), tapping the energy potential in high-power geothermal wells can be restricted by the ability to specify materials that will withstand the extreme environmental conditions. 

Geothermal brine reservoirs typically pose severe corrosion problems for operators—due to the combination of steam, water, and brine at elevated temperatures; the presence of hydrogen sulfide (H2S) and carbon dioxide (CO2); and high chloride content—yet these resources can also yield high-enthalpy steam that produces higher power outputs, so they have become very desirable fields to develop.

Since the early 1990s, titanium has been used in the Salton Sea KGRA (Southern California) to control the excessive corrosion experienced in production wells. Early corrosion testing in the geothermal brine, however, showed that unalloyed titanium was prone to localized attack under the most severe conditions in these brines.