Sensitivity analysis of mass transfer and enhancement factor correlations for the absorption of CO2 in a Sulzer DX packed column using 4-diethylamino-2-butanol (DEAB) solution

Abstract In this study, a rate-based model of post-combustion CO2 capture was developed for an absorption column packed with Sulzer DX. A new amine solution, 4-diethylamino-2-butanol (DEAB), was applied to the absorber as an active CO2 capture solvent, and a sensitivity analysis on mass-transfer coefficients in liquid and gas phases ( k L and k G ), effective interfacial area ( a e ), and enhancement factor ( E ) correlations was conducted to enhance the performance of the absorber. In the modeling, the absorber was divided into two sections—low capacity (less than 0.5 mol CO2/mol DEAB) and high capacity (more than 0.5 mol CO2/mol DEAB)—to improve model prediction accuracy, especially at high CO2 loading ( α CO 2 ). At α CO 2 of less than 0.5, the CO2 equilibrium molar concentration ( C CO 2 , e ) was neglected, while at higher α CO 2 , the Deshmukh–Mather activity coefficient model was used to calculate C CO 2 , e . The solution procedure was validated against the axial experimental data of the CO2 mole fraction in the gas phase ( y CO 2 ) and the liquid-phase temperature ( T L ). Then, a sensitivity analysis was performed for the profiles of α CO 2 , y CO 2 , H2O mole fraction in the gas phase ( y H 2 O ), T L , and gas-phase temperature ( T G ) through various mass-transfer correlations for the Sulzer DX packing. The rate-based model with k L , k G and a e found that the correlation coefficient ( R 2 ) and average absolute relative deviation ( AARD % ) of y CO 2 data were 0.9889 and 3.12, and those of T L data were 0.9685 and 2.09. The sensitivity analysis of various E correlations also revealed no significant difference between the calculated E values using the different relationships. Finally, the effects of α CO 2 , T L , and liquid flow rate ( L ) as the most important parameters of the absorber on the E value were investigated. The results indicated that α CO 2 has a significant impact on the E values and consequently on the reaction rate.