CO2 removal from a gas stream by membrane contactor

Gas–liquid membrane contactors were applied to remove carbon dioxide from a gas stream by using an aqueous monoethanolamine (MEA) solution as absorbent. Various modules composed by different numbers of commercial polypropylene capillary membranes were constructed and tested in a laboratory-scale plant fed with a N2–CO2 gas mixture. Attention was especially focused on the CO2 removal efficiency of the different membrane modules when gas flow rate was increased from 5 up to 360 L/h. A mathematical model was developed to simulate the absorption process in order to predict gas removal efficiency from the knowledge of the system physical parameters. The overall membrane mass transfer coefficient kM was determined and used to compare experimental and predicted removal efficiencies. A good agreement between the developed model and experimental results was found.