Modeling the effect of feed gas perturbation on CO2 removal using potassium glycinate in a membrane contactor

Gaseous-solvent membrane absorption process is a smart approach for removing impurities such as CO 2 present in natural gas, flue gas, and biogas into aqueous solvents. Potassium glycinate solvent has better CO 2 absorption performance compared to traditional solvents. However, hollow fiber membrane design has limitations, as the presence of the membrane adds additional resistance to mass transfer compared to conventional solvent absorption. To reduce the effect of this additional resistance, it is necessary to increase the mass transfer in the gas and solvent phase boundary layers. This study aims to increase the mass transfer in the gas phase layer without interfering with membrane structure by oscillating the velocity of the feed gas. Consequently, an unsteady state mathematical model was developed and solved using Comsol Multiphysics. The simulation results reveal an optimal oscillation frequency that enables high CO 2 removal to be achieved. Under specific operating conditions and without feeding disturbance, the maximum removal rate was about 30%. Applying a feed gas oscillation frequency of 0.05 Hz doubles this to about 70% for CO 2 removal.