Simulation of carbon dioxide recovery from flue gases in aqueous 2-amino-2-methyl-1-propanol solutions

The modeling and simulation of the absorption of dilute CO2 into falling film of aqueous solutions of a sterically hindered amine, 2-amino-2-methyl-1-propanol (AMP), was carried out using COMSOL Multiphysics Version 3.3. The operating cases were divided in gas turbine cases (CO2 3 mol%) and boiler cases (CO2 8.5 mol%). The key operating parameters for the studied cases are CO2 partial pressure, operating temperature and amine concentration in the aqueous solution. The simulation focused on: (1) CO2 loading in aqueous AMP solution; (2) contact time to reach equilibrium; (3) pH of rich AMP aqueous solution; and (4) total required interfacial area/circulated AMP aqueous solution. The modeling was validated by comparison with experimental results for CO2 loading available in the literature, with deviations below 4%. High operating pressure, low operating temperature, and low AMP aqueous concentration increase CO2 loading. The compression need for gas turbine flue gas was found to be higher than for boiler flue gas. The pH of rich AMP aqueous solution at maximum CO2 loading was 8. The needed contact time to reach equilibrium decreases with temperature increases. The results were utilized to estimate the lower bound to the size of structured packed columns to absorb CO2 from flue gases.

► Simulation of CO2 absorption in solutions of 2-amino-2-methyl-1-propanol.
► Key parameters are CO2 partial pressure, temperature, and amine concentration.
► Model deviates by less than 4% from literature results for CO2 loading.
► pH of rich AMP aqueous solution at maximum CO2 loading was 8.
► Lower bound to the size of absorption structured packed columns is suggested.