Investigation of Mixed MEA-Based Solvents Featuring Ionic Liquids and NMP for CO2 Capture: Experimental Measurement of CO2 Solubility and Thermophysical Properties

摘要

Alkanolamine solutions are used in the industry worldwide to remove carbon dioxide and hydrogen sulfide from natural gas, but such technologies have disadvantages. This study aimed to investigate the new hybrid amine solvents for carbon dioxide capture and their potential to reduce the disadvantages of amine technology. The solubility of carbon dioxide in hybrid solvents with different mixtures of monoethanolamine, water, n -methyl-2-pyrrolidone, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, and 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide was measured at temperatures of 298.15 and 313.15 K by a static synthetic method. The viscosity, density, speed of sound, and evaporation rates for the hybrid solvents were also measured. Experimental observations indicate that the solubility of carbon dioxide in a hybrid solvent of n -methyl-2-pyrrolidone + monoethanolamine was greater than that of the aqueous amine solvent, except at low pressures depending on the concentration of amine. The addition of an ionic liquid to the amine solution reduced the volatility of the solvent and decelerated the evaporation rate of amine, while the loss of ionic liquid was almost zero. However, the addition of an ionic liquid to n -methyl-2-pyrrolidone-containing monoethanolamine solvent or the aqueous monoethanolamine solvent decreased the solubility of carbon dioxide and increased the viscosity of the solution.