(85e) Amine Blending Optimization for Maximizing CO2 Absorption Capacity in a MEA - Mdea -Water System Using the Thermodynamic Model

This paper reports the During thermodynamic modeling, Kent Ensiberg using equilibrium constants and DM model using activity coefficient electronic NRTL and UNIQUAC models were used. Also newly measured experimental data for CO₂ solubility in a blended aqueous solution of Monoethanol amine (MEA) and Methyldiethanolamine(MDEA) at different amine mixing ratios (MEA:MDEA:H₂O = 9:21:70, 15:15:70, and 21:9:70 wt %) and working temperatures (323.15, 343.15, 373.15 and 383.15 K)under CO2 partial pressures of up to 400 kPa. The successive substitution method [1] was used for calculating the mole fractions of all molecules (four molecules) and electrolytes (three cations and four anions) from the equilibrium, along with the material and charge balance equations (11 equations). Using the above mentioned thermodynamic models, the partial pressures of CO₂ in the gas phase, mole fractions of all components in the liquid phase, heats of absorption, and cyclic capacities of CO₂ according to the absorption/desorption temperature and the blending ratio of MEA/MDEA/H₂O were estimated. We can also predict the ratio that represents the optimal efficiency of the amine. The regeneration energy the sum of sensible heat, latent heat, and heat of reaction, was calculated according to the amine blending ratio using the “shortcut method” [1], the Novel shortcut method suggested by Lee et al. was used to investigate regeneration energy of stripper for process optimization. In the process, besides the cyclic capacity and heat of absorption, the effect of sensible heat and latent heat must be considered simultaneously.Therefore, the most reliable method to determine the amine blending ratio is regeneration energy minimization.