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

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 0.5 mol CO₂/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.