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

Abstract

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.

Investigation of the Solubility of Methane and Ethane in Hybrid Sweetening Solutions of 2-Aminoethanol and 1-Methylpyrrolidin-2-one/Water

“…Literature data for the solubility of CO 2 (moles of CO 2 in liquid phase divided by the total moles of solvent) in NMP (▲); and MEA (1) + NMP (2) with different MEA mass compositions: w 1 = 0.1025 (●), w 1 = 0.2032 (■), and w 1 = 0.3037 (◆) at 313.15 K …”

“…32 Results indicated that replacing water with NMP in the aqueous MEA solvent with MEA mass fraction of 0.1 greatly increases CO 2 solubility by almost 81% at pressures between 0.21 to 2 MPa. 32 Despite this, it is important to conduct further research on the solubility of other natural gas constituents, such as methane and ethane, in hybrid solvents. This information is crucial for process design and optimization, as well as for comparing the loss of hydrocarbons between conventional and hybrid solvents.…”

“…21 Results in the literature show that mixing amines with physical solvents in hybrid solvents for CO 2 solubility decreases the corrosion rate of process equipment, 22 reduces heat consumption, 23−27 improves reaction kinetics and absorption rate, 16,17,28−31 and increases absorption capacity. 1,32,33 A previous study measured the solubility of CO 2 in conventional aqueous monoethanolamine (MEA) solvents and hybrid solvents of MEA and n-methyl-2-pyrrolidone (NMP). 32 Results indicated that replacing water with NMP in the aqueous MEA solvent with MEA mass fraction of 0.1 greatly increases CO 2 solubility by almost 81% at pressures between 0.21 to 2 MPa.…”

Electrochemical reduction of CO2 in the captured state using aqueous or nonaqueous amines

“…In nonaqueous media, speciation among carbamic acid and carbamate is similarly sensitive to temperature and pressure as in aqueous media, with higher temperatures and lower partial pressures of CO 2 favoring carbamate ( Kortunov et al., 2015b ). Solvents examined for nonaqueous capture range broadly, for example, dimethyl sulfoxide ( Kortunov et al., 2015b ), ethanol ( Versteeg and van Swaaij, 1988 ), propylene carbonate ( Karlsson et al., 2019 ), or n-methyl pyrrolidone ( Ebrahiminejadhasanabadi et al., 2021 ). These solvents are not always relevant to electrochemical systems as discussed later.…”

Controlled preparation of CaO adsorbents by microsyringe titration technology for CO2 capture

“…Therefore, methods to control, capture, and use industrial CO 2 emissions should be widely studied. For example, Ebrahiminejadhasanabadi et al 6 . have studied CO 2 capture using a mixture of ionic liquids and N‐methylpyrrolidone (NMP) as a solvent and Zhang et al 7 .…”