Experimental analyses of mass transfer and heat transfer of post-combustion CO2 absorption using hybrid solvent MEA–MeOH in an absorber

Abstract

• Mass transfer of MEA–MeOH was comprehensively investigated. • The K G a v of MEA–MeOH is higher than that of MEA–H 2 O. • MeOH is vulnerable to evaporate and should be operated at a low temperature. • Optimizing operating conditions can reduce solvent evaporation. The performance of CO 2 absorption into a hybrid solvent such as monoethanolamine (MEA) in methanol (MeOH) was experimentally investigated in a lab-scale absorber packed with Sulzer DX-type structured packing, and compared with that of aqueous MEA solution. The experiments were performed at various key operating conditions over a MEA concentration range of 2.5–5.0 kmol/m 3 , a CO 2 lean loading range of 0–0.373 mol/mol, a liquid flow rate range of 2.92–16.09 m 3 /m 2 h, an inert gas flow rate range of 24.37–63.54 kmol/m 2 h, a CO 2 partial pressure range of 6.7–13.8 kPa, and an inlet liquid temperature of 10 °C. The absorption performance was presented in terms of the overall gas phase mass transfer coefficient ( K G a v ), CO 2 concentration and system temperature profiles along the height of the absorber, and the system temperatures at the bottom and the top of the absorber, T bot and T top , respectively. It was found that the K G a v for MEA–MeOH was higher than that of MEA–H 2 O. In addition, the experimental results showed that key operating parameters such as MEA concentration, CO 2 loading, liquid flow rate and inert gas flow rate have large effect on the performance of CO 2 absorption into the MEA–MeOH.