A mass transfer model based on a linear driving force approximation is widely used in the numerical simulation of pressure swing adsorption processes. This approximation involves a proportionality constant that is dependent on the cycle time. Whereas graphical correlations have been given and curve fitting of experimental data has also been used for estimation of the proportionality constant, in the present study a new approach based on time-dependent Sherwood number as used in the modeling of extraction processes is suggested for this estimation. PSA simulation model predictions using linear driving force parameters calculated by this approach are compared with experimental data on the separation of CO2/N-2 mixtures with activated carbon as the adsorbent.