Catalytic-CO2-Desorption Studies of DEA and DEA–MEA Blended Solutions with the Aid of Lewis and Brønsted Acids

Heat-duty reduction is the major challenge in CO 2 desorption and amine regeneration. The use of a combination of heterogeneous catalytic desorption with improved amine solvents is a novel approach to address this issue. We studied CO 2 -desorption tests of noncatalytic diethylamine (DEA) solvents as a benchmark and focused on five blended amines (DEA–monoethanolamine, MEA; 4.5:0.5 to 2.5:2.5 M) with three types of catalysts (γ-Al 2 O 3, H-ZSM-5, and 2:1 blended γ-Al 2 O 3 –H-ZSM-5) to explore the synergy effects of DEA-based amine blends with solid catalysts. The heat duty and CO 2 production of each case scenario were tested for six sets of solutions with initial loading of 0.5 mol of CO 2 per mole of amine at 363–378 K and were compared with those of 5 M DEA solvents. The results showed that the three catalyst conditions (blended catalyst, H-ZSM-5, and γ-Al 2 O 3 ) followed different trends at rich and lean loadings. Finally, both 5 M DEA and 4.5:0.5 M DEA–MEA with blended catalysts exhibited very low heat duties of 151.2 and 168.0 kJ per mole of CO 2 at loadings of 0.50–0.20 mol per mole of amine at 378 K among the six solutions. Both approaches proved to be the most-energy-efficient amine solutions whereas the blended amine with blended catalysts was the best strategy that was applicable in the CO 2 desorber.