Modeling of CO2 post-combustion capture using membrane contactors, comparison between one- and two-dimensional approaches

This work presents a numerical comparison between a one-dimensional and a two-dimensional model for CO2 capture through solvent absorption with chemical reaction in a hollow fiber membrane contactor. The relevance of the two approaches is discussed. Industrially relevant operational conditions of post-combustion capture using MEA as reactive solvent were applied for both models. Variable gas and liquid mass transfer resistances, depending on the concentrations and the fluids velocity, were employed for the one-dimensional approach, while differential mass-balances considering convection, diffusion and reaction contributions were employed for the two-dimensional approach. The space-averaged specific molar CO2 absorbed flux estimated by both models was almost identical, with a maximum relative difference of 5.73% for membrane permeabilities (ε/τ) comprised between 0.001 and 0.2 and external fiber radiuses comprised between 0.2 and 0.9 mm. Thus it turns out that the one-dimensional approach provides results similar to a two-dimensional approach in the investigated domain with significant lower calculation times.