Reduced energy consumption and enhanced CO₂ desorption performance of non-aqueous ionic-liquid-containing amine blends with zeolites

Excessive emissions of carbon dioxide (CO₂), a primary greenhouse gas, can cause serious environmental concerns, such as climate change and global warming. Therefore, carbon capture, utilization, and storage (CCUS) strategies are crucial for reducing the global carbon footprint. However, the considerable energy penalty in the regeneration of CO₂-loaded solutions is a critical challenge encountered in the industrial application of amine-based post-combustion CO₂ capture technology. Therefore, an alternative pathway involving the use of zeolite catalysts was demonstrated in this study to decrease the energy requirement. The regeneration behavior of two different amine systems, namely monoethanolamine (MEA; 5 M)-1-hexanol and MEA (4 M)-1-butyl-3-methylimidazolium acetate (1 M) ([bmim][Ac])–hexanol, with three different modified zeolites (HZSM-5, H-ferrierite (FER), and H-mordenite (MOR)) were studied. The results revealed that the catalyst enhanced the CO₂ desorption performance of the non-aqueous hybrid system and reduced the relative energy consumption compared to those of the catalyst-free runs. The zeolite-enabled enhancements of the desorption performance of the rich MEA-hexanol solvent were ordered as follows: HZSM-5 > FER > MOR. HZSM-5 showed a higher catalytic performance than that of FER and MOR, and reduced the heat duty by ∼ 45% compared with that of the catalyst-free test. The zeolite catalysts decreased the desorption time for the regeneration of rich non-aqueous solutions by 25%–30% compared to that of the blank run. In summary, the results contribute toward a comprehensive understanding of the combination of non-aqueous amine blends and zeolite catalysts as an energy-efficient strategy for decreasing the energy consumed during regeneration.