Corrosion Test Setup for Steel in the Binary System Supercritical CO2 and Water

Abstract This work addresses corrosion testing in order to study the corrosion behavior of carbon steel in supercritical CO2. It was aimed to set up a cost-effective corrosion testing procedure to perform a series of immersion tests with defined test conditions to allow the determination of corrosion rates by gravimetric evaluation. The experimental program covers a variety of possible conditions in Carbon Capture and Storage (CCS) applications in which the specimens have been exposed, among different water quantities, CO2 partial pressure and temperature have been evaluated. The setup enables corrosion testing described in the experimental section of this work and thereby incorporates pressurized CO2 in the range of 50 bar (725 psi) up to 100 bar (~1450 psi) as well as a temperature range between 50°C and 140°C. By variation of the ratio between electrolyte quantity and surface area of the coupons the corrosion behavior has been studied for defined temperature and pressure conditions. Main subjects of this research are to enable testing and to evaluate the influence of different water contents, pressures and temperature to the resulting corrosion rates as well as the impact of immersion time variation to the corrosion behavior of steels. Moreover, determined corrosion rates obtained from the experiments provide an overview of the corrosion behavior and the suitability of carbon steel for use-cases exposed in scenarios with present binary system of carbon dioxide and water for different pressures and temperatures. In particular the possibility of testing the impact of pressure, temperature and water quantities in the CO2 was taken into consideration for design of the test setup. The test setup will serve future projects handling supercritical CO2 and contributes as input for material selection and identification of corrosion mitigation initiatives by gaining experimental data.