CFD Modeling of CO₂ Desorption from Aqueous MDEA Solution by Coupling Phase Transfer with Reaction Kinetics

Out of all postcombustion CO2 capture technologies, chemical absorption with solvents, especially amine-based solvents, is the most mature available technology to date. In this solvent-based CO2 capture technology, the first stage is absorption, followed by desorption. Many studies have been done on developing a computational fluid dynamics (CFD) model for the amine-based absorption process. However, limited studies have been done on the desorption process. The focus of this work was on developing a CFD model framework for the CO2 desorption process. A Euler–Euler multiphase CFD model framework was developed to study the complex hydrodynamics and reaction kinetics between the CO2 and methyldiethanolamine (MDEA) desorption processes using an open-source software OpenFOAM. Two-phase counter-current gas–liquid flow was considered in this work to study the hydrodynamics and reaction kinetics. A new mass transfer model was developed in OpenFOAM to account for the reaction between CO2 and MDEA. The predicted mole fraction of CO2 with the developed model agreed well with the experimental data given in the literature for different operating conditions. A parametric study on the effects of the mass transfer coefficient, temperature, and porosity on the mole fraction of CO2 was also conducted.