Carbon dioxide absorption in a packed column using imidazolium based ionic liquids and MEA solution

• CO2 absorption in [Bmim][Ac], [Emim][Ac] and MEA in packed column is compared.
• Mass transfer was calculated based upon resistance in series model.
• Enhancement factor for absorption reaction was estimated for both ILs and MEA.
• Experimental and calculated mass fluxes CO2 were found to be in agreement.
• Advantages and drawbacks of investigated ILs and MEA were discussed.

The study of CO2 absorption in ionic liquids: [Emim][Ac], [Bmim][Ac] and 15 wt.% MEA solution in a packed bed column is presented. Absorption column of inner diameter 0.05 m and 0.35 m length was filled with Raschig rings ϕ5 mm × 5 mm × 1 mm. Investigations were performed at atmospheric pressure what is important in the case of post combustion flue gases. The influence of mass transfer resistances in gas and liquid phase as well as initial CO2 concentration and absorption temperature on CO2 removal efficiency was investigated. In calculations the resistance in series model of the absorption process was applied. The estimated values of enhancement factor of the reaction between CO2 and investigated liquids were used to predict mass fluxes of absorbed carbon dioxide for both ILs and MEA solution. The comparison of experimental and calculation results show that in the same experimental conditions the investigated ILs and MEA solution have comparable CO2 absorption capacities. The liquid side mass transfer coefficients in the case of ILs are several times lower than for MEA solution. The research for new ILs characterized by chemisorption mechanism, low viscosity and price is needed to take advantages of applying ionic liquids in the process of CO2 separation in a packed column.