Evaluating CO₂ Desorption Activity of Tri-Solvent MEA + EAE + AMP with Various Commercial Solid Acid Catalysts

Abstract

The Paris Agreement and one of its goals, “carbon neutrality,” require intensive studies on CO2 absorption and desorption processes. When searching for ways of reducing the huge energy cost of CO2 desorption in the amine scrubbing process, the combination of blended amine with solid acid catalysts turned out to be a powerful solution in need of further investigation. In this study, the tri-solvent MEA (monoethanolamine) + EAE(2-(ethylamino)ethanol) + AMP(2-amino-2-methyl-1-propanol) was prepared at: 0.2 + 2 + 2, 0.5 + 2 + 2, 0.3 + 1.5 + 2.5 and 0.2 + 1 + 3 mol/L. The heterogeneous catalytic CO2 desorptions were tested with five commercial catalysts: blended γ-Al2O3/H-ZSM-5, H-beta, H-mordenite, HND-8 and HND-580. Desorption experiments were conducted via a recirculation process with direct heating at 363 K or using temperature programming method having a range of 303–363 K. Then, the average CO2 desorption rate, heat duty and desorption factors were studied. After comparison, the order of CO2 desorption performance was found to be HND-8 > HND-580 > H-mordenite > Hβ > blended γ-Al2O3/H-ZSM-5 > no catalyst. Among the other combinations, the 0.2 + 1 + 3 mol/L MEA + EAE + AMP with HND-8 had a minimized heat duty (HD) of 589.3 kJ/mol CO2 and the biggest desorption factor (DF) of 0.0277 × (10−3 mol CO2)3/L2 kJ min. This study provided a kind of tri-solvent with catalysts as an energy-efficient solution for CO2 absorption and desorption in industrial CO2 capture pilot plants.

Keywords

• catalytic CO₂ desorption
• carbamate stability
• tri-solvent
• coordinative effect