Comparison of CO2 absorption in DETA solution and [bmim]-[PF6] using thermodynamic and process modelling

Abstract

Non-conventional amines are being research around the world to overcome the problems associated with traditional and conventional amines such as monoethanolamine (MEA) and methyldiethanolamine (MDEA). Having appropriate and specific process and thermodynamic models for these amines is vital to recognize their applicability and performance for CO2 absorption. However, studies on process modelling of these types of amines are very limited. In this study, the rate-based modelling was utilized for a packed column to obtain profiles of operating variables for CO2 absorption by Diethylenetriamine (DETA) solution. Deshmukh-Mather (D-M) method as thermodynamic modelling was incorporated in the rate-based model. The process model was validated using experimental data from the literature. Additionally, a sensitivity analysis of mass transfer correlations was performed on the temperature and concentration profiles. The effect of different operational parameters on the CO2 removal efficiency was studied, and the CO2 absorption efficiency of DETA solution was compared with that of an ionic solvent, 1-n-butyl-3-methylimidazolium hexafluorophosphate ([bmim]- [PF6]). The effect of different parameters on the CO2 removal efficiency highlights the need to find optimum operating parameters for absorber column to achieve the maximum absorption efficiency. Although the absorption efficiency of CO2 by ionic solvent was higher than that of DETA solution under the same operational conditions, the advantages, and the disadvantages of each solvent in CO2 capture processes should be considered without compromising the solvent performance.