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Reduction of energy requirement of CO2 desorption from a rich CO2-loaded MEA solution by using solid acid catalysts

Zhang, Xiaowen, Zhang, Xin, Liu, Helei, Li, Wensheng, Xiao, Min, Gao, Hongxia, Liang, Zhiwu
Applied energy 2017 v.202 pp. 673-684
Fourier transform infrared spectroscopy, X-ray diffraction, absorption, carbon dioxide, catalysts, desorption, ethanolamine, heat, solvents, surface area
In this work, the regeneration of rich CO2-loaded monoethanolamine (MEA) solvent with two catalysts (e.g. SAPO-34 and SO4²⁻/TiO2) was investigated in order to reduce the energy requirement for solvent regeneration. The regeneration behavior with and without catalyst of a 5M MEA solution with an initial CO2 loading of 0.5molCO2/mol amine at 96°C was studied to compare their CO2 desorption rate and heat duties. The results show that the two solid acid catalysts can reduce the heat duty for solvent regeneration and increase the CO2 desorption rate in comparison with blank test. The mechanism of CO2 desorption with catalyst in 5M MEA was proposed based on the result of catalyst characterization (e.g. N2 absorption/desorption experiment, Py-IR, NH3-TPD, FT-IR and XRD) to better understand the desorption process. The results indicate that SAPO-34 with the higher joint value of Brϕnsted/Lewis acid sites ratio (B/L) and mesopore surface area (MSA) shows the faster CO2 desorption rate and lower heat duty than SO4²⁻/TiO2. Based on the experimental results, the addition of solid acid catalysts into amine solution could be considered as one of choices to reduce the heat duty for CO2 desorption from CO2-loaded amine solvent.