Performance and stability of a bio-inspired soybean-based solvent for CO2 capture from flue gas

A novel bio-inspired soybean-based solvent (SBB solvent) was formulated for the capture of CO2 with the partial pressure less than 15 kPa in the flue gas. The performance of the SBB solvent was thoroughly characterized in terms of equilibrium solubility of CO2, the heat of CO2 absorption, vapor pressure of the SBB solvent, and the CO2 absorption flux under different operating conditions including CO2 partial pressure in the flue gas, initial CO2 loading in the SBB solvent, SBB solvent concentration, and temperature. The results showed that the equilibrium solubility of CO2 in the SBB solvent was much lower than that in the conventional amine-based solvent at the regeneration condition. The heat of CO2 absorption is only at half of the monoethanolamine (MEA). The near-zero vapor pressure made the SBB solvent as a promising and environmentally friendly solvent for CO2 capture. The optimized concentration of the SBB solvent was 1.0 M for the effective absorption of CO2 from the flue gas. The CO2 absorption performance can be further improved by integrating the use of high concentration SBB solvent with reduced CO2-gas mass transfer resistance. Both thermal stability and oxidative stability of the SBB solvent were evaluated through a 120 h CO2 absorption-desorption experiment. The SBB solvent showed high thermal stability at the regeneration temperature up to 200 degrees C, and also excellent oxidative stability with the O(2 )concentration up to 17% in the flue gas.