Zeolite catalyst-aided tri-solvent blend amine regeneration: An alternative pathway to reduce the energy consumption in amine-based CO2 capture process

The extensive energy penalty of CO 2 -loaded solution regeneration is one of the most crucial challenges facing industrial application of amine-based CO 2 capture technology. Here, to decrease the energy requirement, the regeneration behaviors of the rich 5 M monoethanolamine (MEA) and 3 M MEA-2.5 M N-methyl-diethanolamine (MDEA)−0.5 M piperazine (PZ) tri-solvent blended amines (tri-blend) with four different solid acid catalysts (H-mordenite, Hβ, HZSM-5 and Al 2 O 3 ) were studied at 98 °C. For the catalyst-free tests, the results revealed that the tri-blend hugely enhanced the CO 2 desorption kinetics and reduced the relative energy consumption compared to 5 M MEA. Based on the results of 13 C NMR, the multiple proton transfer paths and abundant bicarbonate ions in the tri-blend contribute to the improved regeneration performance. Additionally, the use of catalyst further improved the CO 2 desorption activity of the tri-blend. The combination of Hβ and tri-blend presented the best regeneration performance, increasing the desorption performance by 1360.8%, and reducing the relative energy requirement by 66.1% compared with the blank run of MEA. In addition, a plausible catalytic mechanism of solvent regeneration over the solid acid catalyst in the tri-blend was suggested. The superior catalytic performance of Hβ resulted from the large mesoporous surface area, larger number of Brϕnsted acid sites and prominent total acid sites. Furthermore, Hβ displayed excellent stability and had no adverse influence on the CO 2 absorption activity. Results herein manifest that the combination of tri-blend amines with high-efficiency catalyst is exceptional strategy for tremendously decreasing the energy consumption of amine-based CO 2 capture processes, ultimately making this technology more technically and economically feasible.