| The Simplified Local Density (SLD) method is a new engineering approach to model adsorption based on spatial invariance of the chemical potential along with an equation of state. This work extends previous pure fluid applications to binary mixtures and more complex adsorbent geometries (slits, pores). Model predictions are compared to molecular simulations and experimental data. The SLD model can represent adsorption isotherms of Types I-V at subcritical conditions. Supercritical behavior has not been classified, however the SLD approach can accurately represent the complex behavior exhibited at supercritical conditions. In addition, clustering (molecular charisma) in supercritical fluids is modeled by representing infinite dilution by calculating the fluid density in the region around a single solute molecule.;Simple engineering models such as Langmuir and Freundlich cannot represent the variety of experimental adsorption isotherm shapes. On the other hand, molecular simulations represent the behavior, but are not suitable for routine process design. This SLD approach bridges the gap by retaining both the essential physics of the adsorption problem and the simplicity of an equation of state. The SLD approach is demonstrated to be a powerful engineering tool for prediction of adsorption, and requires fewer parameters than previous engineering models. In addition, the SLD approach can be extended to non-ideal gas phase regions without additional parameters. The single parameter used for each adsorbate is temperature- and pressure-independent, permitting extrapolations and predictions of adsorption behavior. |
