Corrosion testing of materials in simulated superheated geothermal environment

Publisher's version (útgefin grein)This paper reports the results of corrosion study for carbon steel, austenitic stainless steel, as well as titanium and nickel-based alloys which were tested in a simulated superheated geothermal environment (SSGE) in flow-through reactors to investigate the corrosion behaviour to aid in the future material selection for high temperature deep geothermal application. The testing fluid was superheated steam (T = 350 °C and P = 10 bars gauge) containing H2S, CO2 and HCl with condensate of pH = 3. The corrosion rate for all samples was negligible but carbon steel was prone to localized damage under a magnetite film with a sulphur rich sublayer.The authors would like to thank the Icelandic Research Fund (RANNÍS, grants no. 163108-051, 163108-052 and 163108-053) and Geothermal Research Group (GEORG) for funding this project. Employees at Innovation Center of Iceland (ICI) and employees at Grein Research for their technical assistance. The authors would also like to give gratitude to Nippon Steel Sumitomo Metals and TIMET for collaboration and providing samples for testing.Peer reviewe

Corrosion Behaviour of Titanium Alloy and Carbon Steel in a High-Temperature, Single and Mixed-Phase, Simulated Geothermal Environment Containing H2S, CO2 and HCl

The corrosion behaviour of a new titanium-based alloy, with nickel, molybdenum and zirconium as the main alloying elements, was studied in a simulated geothermal environment at various phase conditions of a corrosive fluid. Corrosion testing of carbon steel was also conducted for comparison. Both materials were tested at an elevated temperature between 180 and 350 °C and at a 10 bar gauge pressure in H2O containing HCl, H2S, and CO2 gases with an acidic condensate of pH = 3. The study found that the titanium alloy demonstrated good corrosion resistance in a single- and multiphase geothermal environment. In the testing volume, where the boiling of testing fluid occurred, the carbon steel was prone to localized damage of oxide, sulphide and chloride corrosion products. In the superheated testing volume, a homogeneous oxide corrosion layer was observed on the carbon steel. In the testing volume where condensation of the testing fluid occurred, a sulphide layer with an oxide sublayer was formed on the carbon steel