The separation of air for the production of nitrogen by pressure swing adsorption over a carbon molecular sieve is kinetically based. The basic steps involved in a cycle are typically pressurization, high pressure adsorption, countercurrent blowdown and vent. Simulations studies with DAPS (Dynamic Adsorption Process Simulator) were performed to analyze the effect of the pressurization rate and bed length on the performance of a single bed nitrogen pressure swing adsorption unit in the high purity region. Both specific product and yield improve with the bed length due to the reduction in the axial dispersion effect. A comparison between the predictions of the theoretical model and experimental results was carried out.