Deviations due to Ignoring the Skin Layer in Modelling of CO2 Absorption in Asymmetric Hollow Fiber Membrane Contactors

The scope of this study is to model the absorption of CO2 in water via an asymmetric hollow fiber membrane contactor based on the resistance modelling approach. In the previous research, membrane structure was divided into only three regions of shell stream, bulk of membrane and lumen stream, i.e. a symmetric structure, whereas in the current study the role of another important resistance i.e. skin layer was deeply considered. In this way, without considering illegal values for the system tuning parameters the modelling results were enhanced e.g. 1.5 versus 4 for tortuosity. The predictions of the proposed model were confirmed by the experimental data i.e. a percentage of average absolute relative error of less than 6%. The results also showed that the increase in effective surface porosity leads to more descending trend of the mass transfer resistance relative to the bulk porosity that is due to the higher order of magnitude (2 order) of the skin layer resistance in comparison to that of the substrate. In addition, the findings demonstrated that, the model proposed in this work is prone to offer a useful tool to improve our knowledge about the asymmetric membrane contactors.