Updating kinetics data of CO2 absorption by aqueous solutions of alkali salts
Rivera-Tinoco Rodrigo1, Bouallou Chakib 2
1 Centre Energétique et Procédés. MINES Paristech. 60 Bd. Saint Michel. 75006 Paris, France
2 INOSS Group S.A. de C.V. Jesús Contreras No.18, Cto. Escultores. Naucalpan, Edo. de Mex. 53100,
Mexico
Keywords: carbon capture, hydroxide absorption, kinetics, carbon dioxide
Abstract
Carbon capture and storage (CCS) is a promising technology for the avoidance of carbon dioxide
emissions from centralized sources, such as power plants and industry. In spite of reducing
greenhouse gas (GHG) emissions, CCS technologies need to cope with economic parameters. Among
them, the cost of capturing CO2 is high enough to convert the technology into an unattractive and
uncompetitive way to reduce industry GHG emissions. Some mature and rising technologies are
amine scrubbing, ammonia scrubbing, membrane-solvent scrubbing, solidification with calcium or
magnesium, and alkali scrubbing. This last technology has proven its adequacy for CO2 absorption
from air. For us, this technology seems promising for centralized and decentralized carbon emission
sources. Lack of kinetic data, however, makes difficult to explore full potential of this technology, as
well as potential synergies with other industrial processes. This work provides new kinetics data of
CO2 absorption by alkali solutions: Lithium, sodium and magnesium.
First studies on carbon dioxide absorption by hydroxide aqueous solutions date from late 1950’s.
Nijsing et al (1959) performed kinetic studies of CO2 on laminar jet flow and wet wall systems.
Assumptions on pseudo-first order and second-order reactions are suggested as means to model the
absorption of CO2 by hydroxides. Any further studies with accurate and modern equipment have
been performed since the 1960’s. Intriguing is that several highlights on carbon capture works
published today assume old kinetic data. Our work presents modelling of kinetics for alkali-CO2
systems and makes question raise about pseudo-first order assumptions until today considered.
References
Nijsing, R.A.T.O, Hendriksz R.H., Kramers, H. Absorption of CO2 in jets and falling films of electrolyte
solutions with and without chemical reaction. Chemical Engineering Science 1959;10:88-104.
Roizard Christine, Wild Gabriel, Charpentier Jean Claude. Absorption avec réaction chimique.
Techniques de l’ingénieur. Traité de Génie des procédés. J 1079