Mixture Absorption System of Monoethanolamine−Triethylene Glycol for CO2 Capture

In this paper, a mixture system without water but composed of monoethanolamine (MEA) and triethylene glycol (TEG) is designed for CO 2 capture. The solubility of CO 2 in pure TEG and MEA−TEG solutions is determined, respectively, showing that the solubility of CO 2 in TEG is generally consistent with Henry’s Law and the value is higher than that in water. The solubility of CO 2 in MEA−TEG solutions significantly increases with the increase of MEA, showing the characteristics of chemical reaction absorption. The absorption mechanism study shows that TEG does not act as a reaction agent. There is only one reaction between CO 2 and MEA. The absence of water in the new system leads to the absence of dissociation of protonated MEA and formation of carbamate (MEACOO − ). This is much different from the MEA−water system. A mathematical model is also developed for predicting the solubility of CO 2 in the new system. The results show that the absorption and desorption can be realized at relatively lower temperatures (lower than 353.15 K), which may provide advancement in two aspects: low energy consumption with less solvent evaporation and avoidance of MEA’s degradation caused by high-temperature operation.