Investigation on the Phase-Change Absorbent System MEA + Solvent A (SA) + H₂O Used for the CO₂ Capture from Flue Gas

Abstract

Amine-based CO2 postcombustion capture is a commercialized technology for recovery CO2 from flue gas, and the energy consumption is concentrated in the regenerative stage. The phase-change solvent system, monoethanolamine (MEA, absorbent) + solvent A (SA, solvent) + water (solvent), was investigated on the performances of CO2 absorption and desorption. CO2-rich solvent can be continuously separated for the feeding flow of the regeneration tower; thereby, it significantly reduces the energy of regeneration. The results show that the solvent with suitable composition can easily separate the CO2-rich phase from the solvent, and the CO2-rich phase accounts for more than 98% of the total CO2. At 293–333 K, the temperature has no significant effect on the absorption rate and phase equilibrium. The estimation of energy consumption shows that the reboiler work can be reduced by 43.6% compared with that using 20 wt % MEA aqueous solution.