The absorption of carbon dioxide gas by monoethanolamine (MEA) in the packed tower is the most common method for the CO2 capture. The present study describes the set-up and operation of a laboratory-scale CO2 capture unit in detail, as the closed cycle of the absorption/desorption process continuously operated at the different operating conditions. The effect of six independent variables was investigated on CO2 absorption in three levels. To analyse the results, Response Surface Box-Benhken design method was applied. The absorption unit was evaluated in terms of absorption percentage (Phi), the overall gas phase mass transfer coefficient (K(G)a(V)), and the specific heat duty of the reboiler (eta). The results of the analysis indicated that the MEA concentration in the solvent had the most significance, whereas the input solvent temperature had the least effect upon the overall gas phase mass transfer coefficient. The response surface optimization was also carried out to determine the optimal operating conditions to maximize K(G)a(V) and minimize eta. The results demonstrated that at an inlet solvent temperature of 45 degrees C, solvent flow rate of 1.25 L/min, gas flow rate of 100 L/min, reboiler heat load 1.4 kW, MEA concentration 30 wt.%, and the CO2 concentration of 15 vol.%, eta was at the minimum value of 3.88 MJ/kg CO2, while K(G)a(V) was at the maximum value of 4.59 kmol/m(3).h.kPa. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.