Intensification potential of hollow fiber membrane contactors for CO2 chemical absorption and stripping using monoethanolamine solutions

In this work, the intensification potential of Hollow fiber membrane contactors (HFMC) for CO2 capture by chemical absorption using amine solution have been evaluated by simulation, for both absorption and desorption steps. The simulations have been achieved considering typical industrial relevant conditions for post-combustion capture, based on CASTOR campaign at the Esbjerg pilot plant using packed column, operating at its energetic optimum. Rigorous adiabatic 1D simulations are achieved and revealed important temperature variation as well as significant water transmembrane fluxes in both absorber and desorber. Compared to packed column, a contactor volume reduction (i.e. intensification factor) of about 4 can be achieved in the stripping and absorption section using dry membranes corresponding to a km value of 10−3 m/s and external fiber radius of 200 μm. For significant absorber intensification factor, fibers should have an external radius less than 400 μm and membrane mass transfer coefficient should not be less than 5.10−4 m s−1. HFMC implementation for high temperature stripping is promising providing that membranes resistant to high temperature (i.e. 120 °C) and equally resistant to wetting are available. Due to important water transfer in both absorber and desorber, in addition to wetting of porous membranes by liquid breakthrough, a new possible limiting phenomenon for HFMC technology is wetting by capillary condensation. Even though net solvent losses in the membrane contactor are smaller than those calculated for packed columns, a scrubbing section after the HFMC is still required for solvent recovery in order to meet solvent concentration standard in the CO2 depleted gas stream. This issue represents an opportunity for the membrane contactor technology based on dense-film MEA selective composite membrane.