Analysis of the Roles of Distributed Mass Transfer Resistances for Adsorbents Using Frequency Response Methods

Frequency response methods are used to analyze a general model that has been developed to consider the various mass transfer resistances in adsorbents. The model can consider a combination of resistances in series and parallel including (i) external mass transfer, (ii) macropore diffusion, (iii) micropore diffusion, (iv) a surface barrier represented by a linear driving force, and (v) axial dispersion. Heat effects can be added for a non-isothermal system. Families of curves for different resistances have been developed to facilitate the use of frequency response for recognizing mass transfer mechanisms. Experiments for different systems have been performed using both concentration-swing and pressure-swing frequency response methods to examine the roles of mass transfer resistances with the diffusion model.