Analysis of CO sub(2) Separation with Aqueous Potassium Carbonate Solution in a Hollow Fiber Membrane Contactor

Hot potassium carbonate solution is a promising absorbent for economical sequestration of CO sub(2) from flue gas. In the present study, a 2D mathematical model was developed to analyze the absorption of carbon dioxide from a gas mixture into an aqueous solution of potassium carbonate using a microporous hollow fiber membrane contactor operated under nonwetted or partially wetted conditions. The set of partial differential equations for the liquid, membrane and gas phases were solved by applying a numerical procedure, and the model results were validated with available experimental data in the literature. A parametric study was done using the validated model in order to achieve an optimized CO sub(2) capture. It was found that the rate of absorption increases significantly with increasing the liquid temperature, and there is an optimum carbonate concentration which gives maximum absorption flux at each solution temperature. A comparison between potassium carbonate and diethanolamine solutions was done under nonwetted and partially wetted conditions. The results revealed that potassium carbonate can give higher CO sub(2) recovery at optimum conditions. Considering the other advantages of K sub(2)CO sub(3) solution over alkanolamines such as lower cost and easier regeneration, it can be a suitable choice for CO sub(2) absorption by hollow fiber membrane contactors.