PREDICTING GAS-ADSORPTION USING 2-DIMENSIONAL EQUATIONS OF STATE

Accurate description of gas adsorption on solids is gaining in importa nce as the number of engineering applications expands. In the present work, a general two-dimensional equation of state (2-D EOS) is present ed and the fugacity equations are derived to describe the adsorbed pha se for adsorption from gas mixtures. Model constants in the 2-D EOS ar e determined from pure adsorption equilibria data and then used to pre dict adsorption of mixtures on both homogeneous and heterogeneous surf aces. The 2-D van der Waals, Soave-Redlich-Kwong, Peng-Robinson, Eyrin g as well as a new 2-D EOS are evaluated for systems which include bot h ideal and nonideal adsorption behaviors. The predictions are compare d with those of other methods, including the Langmuir model and ideal adsorbed solution theory. Various forms of the 2-D EOS are found to be capable of representing azeotropic behavior, and they provide overall the best predictive results (when based on information from pure-comp onent isotherms).