Rate-Based Modeling for Packed Absorption Column of the MEA–CO2–Water System at High-Pressure and High-CO2Loading Conditions

Pandya proposed the first steady-state rate-based model for the chemical absorption process in a packed column using the aqueous CO2–MEA system. Later several modeling studies are also reported based on Pandya’s approach but limited to low pressure (≈1 bar) and low CO2loadings (<0.5 mol/mol). Recently, the interest in processing CO2-rich natural gas at high-pressure conditions has been increased. Therefore, in this study, the Pandya model is modified to simulate the packed absorption column using an aqueous CO2–MEA system for the high-pressure and high-CO2loading range. The sequential chemical reactions, along with the respective mass transfer resistances that occur at low (<0.5 mol/mol) and high (>0.5 mol/mol) CO2loadings, are added. This is achieved by theoretically segmenting the packed column into two sections. This strategy simplifies the computation of subsequent fast and slow reaction regimes that occur over a high-CO2loading range. The gas–liquid nonideal behavior is described using the Peng–Robinson (EOS) and Kent Eisenberg models. The developed model is effectively validated using the experimental data at low- (≈1.03 bar) and high- (50 bar) pressure conditions over a wide CO2loading range (≈0–1.0 mol/mol). In a parity plot between measured and simulated CO2concentration, R2is found to be 0.99 and 0.97, respectively, for the low- (≈1.03 bar) and high- (50 bar) pressure systems. This indicates that the proposed model can accurately predict the critical design parameters at the high-pressure and high-CO2loading conditions, with minimum computational intricacy.