CO2 transfer in an aqueous potassium carbonate liquid membrane module with dense polymeric supporting layers: Influence of concentration, circulation flow rate and temperature

Gas-liquid separation systems have already received considerable attention in a great number of situations of industrial interest. The attention paid to membrane contactors and immobilized liquid membranes have recently increased due to their separation performances. For the sake of simplicity, most experiments are usually performed at room temperature. It is, however, obvious that increasing the temperature would increase the reaction rate and thereby also possibly enhance the system's productivity. This work presents a systematic study of CO2 and H2 transport in a novel flowing liquid membrane (FLM) module with dense membranes separating layers and aqueous potassium carbonate (concentration 0.1-3 kmol/m3) solutions in the temperature range 295-353 K. A model of CO2 transport with reversible chemical reactions through the FLM was developed and compared to a series of experimental data. It was found that increasing the concentration of potassium carbonate as well as the temperature led to large increases in both the CO2 productivity and the CO2/H2 selectivity. The industrial implications of these observations were discussed. Unsteady state transport of CO2 was also investigated and a simple model of gas transfer in the FLM with physical absorption in the liquid phase was developed.