Experimental Study of the Absorption and Regeneration Performance of Several Candidate Solvents for Post-Combustion CO2 Capture

At present monoethanolamine (MEA) remains as the standard industrial solvent for CO2 capture processes. But due to the degradation and high energy consumption problems of MEA, new efficient solvents should be found. In the present work, the absorption and regeneration performance of a hybrid solvent MEA-methanol was studied and compared to the aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA) and triethanolamine (TEA) in a bubbling reactor. Also the performance of MEA-methanol solutions (including the absorption performance, regeneration performance, cyclic absorption performance, density and viscosity) was studied with different MEA concentrations. A pilot-plant CO2 capture test bed was used to study the potential of MEA-methanol to replace aqueous MEA in industrial use. The results showed that the initial absorption rate of MEA-methanol solvent is the fastest compared with other solvents. The 30% MEA-methanol had a faster mass transfer coefficient, a higher CO2 absorption efficiency and a lower regeneration energy consumption than aqueous MEA. And through the study of the reaction heat of CO2 into MEA-methanol and aqueous MEA, it can be concluded that the desorption heat of rich MEA-methanol is only about 30% of rich aqueous MEA solvent in the regeneration process which showed that 30% MEA-methanol solvent is a promising candidate for CO2 capture.