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 CO2-loaded solution regeneration is one of the most crucial challenges facing industrial application of amine-based CO2 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, H beta, HZSM-5 and Al2O3) were studied at 98 degrees C. For the catalyst-free tests, the results revealed that the tri-blend hugely enhanced the CO2 desorption kinetics and reduced the relative energy consumption compared to 5M MEA. Based on the results of C-13 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 CO2 desorption activity of the tri-blend. The combination of H beta 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 H beta resulted from the large mesoporous surface area, larger number of Bromsted acid sites and prominent total acid sites. Furthermore, H beta displayed excellent stability and had no adverse influence on the CO2 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 CO2 capture processes, ultimately making this technology more technically and economically feasible.