Countercurrent absorption of CO2 in a real flue gas into aqueous alkanolamine solutions in a wetted wall column

Abstract

The countercurrent absorption of CO 2 from the flue gas into aqueous alkanolamines has been studied using wetted wall column equipment connected to the stack of a power plant. The absorption rates of CO 2 into aqueous alkanolamines (primary amine (monoethanolamine), hindered amine (2-amino-2-methyl-1-propanol), diol secondary amine (diethanolamine), secondary amine (2-(methylamino)ethanol, 2-(ethylamino)ethanol, 2-(butylamino)ethanol), tertiary amine (2-(diethylamino)ethanol, 4-dimethylamino-1-butanol), diamine (2-(2-aminoethylamino)ethanol)) were measured at 40°C, 10kPa partial pressure, and 2m 3 /h of gas flow rate. From the rate of absorption and the absorption equilibrium results, the secondary amines have as large overall mass transfer coefficients as monoethanolamine. However, the coefficients of the hindered and tertiary amines are small even though the absorbed amounts of CO 2 at equilibrium are large. The CO 2 concentration profiles in a wetted wall column were estimated, and these results are due to the absorption process in connection with the degree of carbamate formation.