Rate of CO₂ absorption of a phase-separation absorbent

In this study, we evaluated the CO₂ absorption characteristics of a phase-separation amine absorbent. The phase-separation absorbent consists of a 30:60:10 (by weight percent) mixture of 2-(ethylamino)ethanol, diethylene glycol diethyl ether, and water. The CO₂ absorption rate of the phase-separation absorbent was measured in a lab-scale counter flow absorber. In addition, the CO₂ transport phenomena in the absorber were analyzed by performing model fitting. The experimental results revealed that the CO₂ absorption rates are different before and after phase separation. In fact, the overall CO₂ absorption capacity coefficient after phase separation is 4.5 times higher than that obtained before phase separation. By changing the gas-liquid ratio, we obtained a CO₂ recovery ratio of over 80% using the model. Thus, the absorption temperature, CO₂ loading, and gas-liquid ratio can be tuned to obtain the desired CO₂ recovery ratio.