T–x diagrams for the CO 2 –H 2 O system: The importance of water content in CO 2 transportation for carbon capture and storage

• Published in: AIChE journal 2024-06, Vol.70 (6)
• Main Authors: Wadsworth, Lindsey A., Wells, Jonathan D., Sloan, E. Dendy, Koh, Carolyn A.
• Format: Article
• Language: English
• ISSN: 0001-1541; 1547-5905
• DOI: 10.1002/aic.18415

When water is present in a CO 2 pipeline, corrosion or plugging can occur due to the formation of liquid water or gas hydrate, respectively. Understanding how corrosion and hydrate plugging can be avoided is important for enhanced oil recovery and carbon dioxide capture and storage processes. If the CO 2 is sufficiently dried prior to transportation, the formation of these problematic free‐water phases can be avoided. In this work, isobaric T–x diagrams were developed from the P–T diagram for the CO 2 –H 2 O binary system. Pressures ranging from just below the lower quadruple point to above the lower critical end point were studied. These diagrams are meant to give the reader a better conceptual understanding of how the water composition in CO 2 –H 2 O mixtures will influence phases that form at different temperatures and pressures. The diagrams are analyzed from the perspective of flow assurance in CO 2 transportation.