Carbon dioxide capture with concentrated, aqueous piperazine

Abstract

Concentrated, aqueous piperazine (PZ) has been investigated as a novel amine solvent for carbon dioxide (CO 2) absorption. The CO2 absorption rate with aqueous PZ is more than double that of 7 m MEA and volatility at 40 ∘C ranges from 10 to 19 ppm. Thermal degradation is negligible in concentrated PZ solutions up to a temperature of 150 ∘C, a significant advantage over MEA systems. Oxidative degradation of concentrated PZ solutions is appreciable in the presence of copper (4 mM), but negligible in the presence of chromium (0.6 mM), nickel (0.25 mM), iron (0.25 mM), and vanadium (0.1 mM). Initial system modeling suggests that 8 m PZ will use 5 to 10% less energy than 7 m MEA. The fast kinetics and low degradation rates suggest that concentrated PZ has the potential to be a preferred solvent for CO2 capture.