Abstract
Post-combustion CO2 capture in a hollow fiber membrane contactor (HFMC), using imidazolium-based room temperature ionic liquids (RTILs) and amino acid ionic liquids (AAILs) as absorbents, was studied through an experimental and modeling approach. Equilibrium solubility of CO2 in RTILs was measured by isochoric pressure drop. Pore wetting was analyzed by measuring surface tension of the RTILs, contact angle and liquid entry pressure (LEP). The experimental work of CO2 capture from a gas mixture was carried out with a laboratory scale unit using a single HFMC for absorption or two coupled HFMCs one for absorption and a second for desorption working simultaneously. Furthermore, robust and rigorous dynamic modelling approaches were developed for isothermal (with RTILs) and non-isothermal (with AAILs) absorption. Both isothermal and non-isothermal models were validated with experimental data and were used to simulate a large range of operating conditions. Initial high values of CO2 absorption rate and experimental mass transfer coefficients decreased with operation time and reached a nearly constant value at pseudo-steady-state. Before reaching pseudo-steady-state, the separation efficiency of coupled process was higher when compared with the absorption with a single module.