The corrosion behavior of carbon steel was investigated under supercritical CO2 (scCO2) –
water systems to simulate the condition of CO2 transportation pipeline in the CO2 sequestration
applications. To understand the thermodynamic properties of scCO2-water systems related to
the corrosion phenomena, thermodynamic modeling were conducted to determine the mutual
solubilities of CO2 and water in the two coexisting phases, and to calculate the concentrations
of corrosive species in the free water at various pressures and temperatures. Carbon steel
samples were exposed to water-saturated CO2, and CO2-saturated water in the pressure
range of 40 to 80 bar at 50oC. The corrosion rate of samples was determined by weight loss
measurements. The surface morphology and the composition of the corrosion product layers
were analyzed by using surface analytical techniques (SEM and EDS).
Keywords: supercritical CO2, thermodynamic modeling, CO2 corrosion, carbon steel