Kinetics of absorption of carbon dioxide in aqueous amine and carbonate solutions with carbonic anhydrase

In the present work the absorption of carbon dioxide in aqueous N-methyldiethanolamine (MDEA) and aqueous sodium carbonate with and without carbonic anhydrase (CA) was studied in a stirred cell contactor in the temperature range 298-333 K. The CA was present as free enzyme and is compared to the opportunity to immobilise CA on particles and on fixed packing. Based on the results with MDEA and sodium carbonate, the observed kinetics as a function of the free enzyme concentration are described. These results were incorporated into the Procede Process Simulator (Arendsen et al., 2012) to determine the impacts of the kinetic benefit of CA on commercial absorber sizing for carbon dioxide capture from flue gases. Based on simulations performed, CA in the absorption solution can provide substantial benefits for reducing absorber sizing with these normally kinetically limited, but energy efficient solvents. It was also shown that CA immobilised to fixed packing material is not a viable option for using CA in a carbon dioxide capture process. (C) 2012 Elsevier Ltd. All rights reserved