Comparative study of CO2 absorption in 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 comparative study of CO2 absorption in ionic liquids: [Emim][Ac], [Bmim][Ac] and 15% MEA solution in packed bed column is presented. Investigations were performed for low pressures, what is important in the case of post combustion flue gases. Absorption column (0.3 m length, inner diameter 0.05 m) was filled with Raschig rings ϕ5 × 5 × 1 mm. The influence of initial CO2 concentration, absorption temperature, gas and liquid flow direction on removal efficiency was investigated. Experiments were compared with calculation based upon resistance in series model of the absorption process in packed column taking into account enhancement factor of reaction between CO2 and investigated liquids. The results show that in the same experimental conditions ILs have comparable CO2 absorption capacities with MEA solution. However ILs need much longer times to absorb the same amount of carbon dioxide from gas mixture. The research for new ILs with lower viscosity and price is needed to take advantages of ionic liquids for the process of CO2 stripping in packed column.