Formation of corrosive aqueous phases in dense phase CO_2

摘要

Extensive Carbon Capture Utilisation and Storage (CCUS) will require pipeline transport of large quantities of liquid and supercritical CO_2. The CO_2 stream will contain impurities that affect both the water solubility and corrosion. The presence of ammonia, MEA and other amines, MeOH, EtOH, glycols, acid (H_2SO_4, HNO_3) and water soluble salts will facilitate the formation of an aqueous phase (free water) and reduce the concentration of water in the CO_2 at which a separate aqueous phase is formed. The present paper presents and discusses experimental solubility data of MEG and TEG in dense phase CO_2 and how the water solubility and the composition of precipitated aqueous phase are affected by impurities. The paper also discusses the experimental approach and the results obtained in corrosion experiments where carbon steel was exposed to aqueous phases containing various concentrations of MEA, ammonium salts, MEG and dissolved corrosion products. The experiments were carried out at 100 bar CO_2 and at 25 and 50 °C respectively.