Modeling CO2 capture with aqueous monoethanolamine

Abstract

Hilliard [M.D. Hilliard, A predictive thermodynamic model for an aqueous blend of potassium carbonate, piperazine, and monoethanolamine for carbon dioxide capture from flue gas, Ph.D. Dissertation, The University of Texas at Austin, Austin, Texas, 2008.] completed several thermodynamic models in Aspen Plus®for modeling CO2 removal with amine solvents, including MEA- H2O- CO2. This solvent was selected to make a system model for CO2 removal by absorption/stripping. Both the absorber and the stripper used RateSepTM to rigorously calculate mass transfer rates. The accuracy of the new model was assessed using a recent pilot plant run with 35 wt% MEA. Absorber loadings and removal were matched and the temperature profile was approached within 5 ∘C. An average 3.8% difference between measured and calculated values was achieved in the stripper. A three-stage flash configuration which efficiently utilizes solar energy was developed. It reduces energy use by 6% relative to a simple stripper. Intercooling was used to reach 90% removal in the absorber at these optimized conditions.