Comparative Study of CO_2 Absorption in Aqueous Mixtures of Methyldiethanolamine (MDEA) and Methanol, focusing on the Temperature and Concentration Influence over the Absorption Rate

摘要

The use of tertiary methyldiethanolamine (MDEA) as an absorbent for the CO_2 removal from process gas streams has increased due to its advantages over primary and secondary amines. Methanol is also widely used as an organic physical solvent for the CO_2 capture. Mixed solvents are expected to have a higher capacity for the acid gases than the solvent alone. The chemical absorption rate of CO_2 was measured in mixtures of MDEA (weight 5%, 15% and 30%) and watermethanol solutions at different% weight relations by using a stirred-cell reactor with plane gasliquid interface. Experiments provided data measured at a range from 283.15 K to 313.15 K operation temperatures. Results show how the solubility of CO_2 varies in all systems involved focusing on temperature and concentration changes. The solubility of CO_2 in the aqueous mixed MDEA with methanol as a solvent becomes significantly greater than in the aqueous amine alone.