Absorption of CO<sub>2</sub> in aqueous blend of methyldiethanolamine and arginine
Ahmed Gomaa Talkhan, Abdelbaki Benamor, Mustafa S. Nasser, Muftah H. El‐Naas, Sayed El-Tayeb, Sahar M Elmarsafy
Abstract
Abstract The objective of this research is to study for the first time the effect of adding l ‐arginine (Arg) amino acid on the solubility of carbon dioxide in aqueous solution of N ‐methyldiethanolamine (MDEA). The study was carried out at different mixing ratios of MDEA and Arg at a total concentration of 2 moles per litre. The CO 2 partial pressure varied from about 10 to 100 kPa, and the temperature varied from 293 K to 323 K. The experimental results showed improved solubility of CO 2 with the addition of Arg at CO 2 partial pressures below 20 kPa. However, for CO 2 partial pressure of above 20 kPa, the addition of Arg caused a decrease in the solubility of CO 2 . The obtained loading data were correlated using a semiempirical (SE) vapour liquid equilibrium (VLE) model with an average absolute deviation (AAD) less than 4.1% between the predicted and the experimental values. An estimation of the heat of CO 2 absorption in the solution was obtained using an analytical expression for Δ H abs derived from the SE model and was found to be in the range of 29‐ to 40‐kJ/mole CO 2 . From the finding of this work, it is anticipated that the studied novel blended solvent will effectively reduce CO 2 capture costs as the CO 2 content of most gas streams is less than 20% by volume, which is specifically true for natural gas and a large number of industrial flue gas streams.