Capture of CO2 by highly concentrated alkanolamine solutions in a rotating packed bed

The capture of CO2 in a rotating packed bed (RPB) using highly concentrated alkanolamine solutions has been proved to be an effective way to enhance the absorption efficiency of CO2. In this investigation, the effects of alkanolamine concentration on the CO2 removal efficiency and mass transfer coefficients (K(G)a) at various lean CO2 loadings were studied. Monoethanolamine and 2-methyl-amino-ethanol solutions were used to absorb CO2 in an RPB. Experimental results showed that increasing the alkanolamine concentration effectively enhanced the CO2 absorption efficiency of a fresh absorbent. For an absorbent with a high CO2 loading, an optimal alkanolamine concentration was observed because the viscosity of the absorbent dramatically increased at high alkanolamine concentration and high CO2 loading. A correlation of K(G)a was proposed and the mass transfer coefficient can be expressed as a function of the free alkanolamine concentration and the viscosity of the absorbent.