CO2 Desorption in Single and Blended Amine Solvents with and without Catalyst

Abstract

In this work, various single and blended amines (namely, MEA, MEA-DEEA, MEA-MDEA, MEA-1DMA2P) with three types of catalysts (H-ZSM-5, MCM-41 and SO42-/ZrO2) were studied to determine the respective roles of catalyst and solvent in heat duty for solvent regeneration and rate of CO2 desorption during the desorption of CO2 from the solvents having an initial CO2 loading of 0.5mol CO2/mol amine at 371K. The results show that performance of the three catalysts in all the four investigated aqueous solution systems followed the trend: H-ZSM-5 > MCM-41 > SO42-/ZrO2. These results highlight the fact that even though HZSM-5 has moderate acidic sites (MAS) as compared to MCM-41 and SO42-/ZrO2, its large Brϕnsted/Lewis (B/L) acid sites ratio coupled with mesopore surface area (MSA) had the greatest effect on heat duty for CO2 desorption as well as rate of CO2 desorption. Furthermore, based on this study, the blended system of aqueous 5M MEA+1M MDEA with H-ZSM-5 provided the best approach for solution regeneration because the strong electron withdrawing chemical structure of MDEA made the solution most prone to CO2 desorption as compared with 1DMA2P and DEEA.