Master curves for mass transfer in bidisperse adsorbents for pressure‐swing and volume‐swing frequency response methods

A general model has been developed for pressure‐swing and volume‐swing frequency response methods with analytical solutions derived to analyze various mass transfer resistances in biporous adsorbents. The model can consider a combination of distributed mass transfer resistances acting independently or in series including macropore diffusion, micropore diffusion, and a surface barrier resistance at the entrance of micropores. Heat effects are included for nonisothermal systems. Temperature variations are shown to be less for pressure‐swing compared with volume‐swing systems. The general model is developed in such a way that information extracted from it is independent of whether a system is batch volume swing or flow‐through pressure swing. Simulation results demonstrate that mass transfer mechanisms can be easily discriminated by the master curves. Isothermal models exhibit one‐step curves, whereas nonisothermal effects are represented by two‐step curves. Examples are given to demonstrate the use of the master curves to describe experimental data. © 2010 American Institute of Chemical Engineers AIChE J, 2011