Determining the corrosive potential of CO2 transport pipeline in high pCO2–water environments

The corrosive potential of carbon steel was evaluated under high pressure CO2–water systems to simulate the condition of CO2 transportation pipeline in the CO2 capture and storage (CCS) applications. To understand the thermodynamic properties of CO2–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 CO2 pressure range of 40–80 bar at 50 °C. 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).