Air separation on carbon molecular sieves, 4A and 5A zeolites by pressure swing adsorption

This work describes the results of a chromatographic study of sorption equilibria and kinetics of nitrogen and oxygen in carbon molecular sieves. The temperature dependence of the experimental equilibrium constants and micropore diffusivity is correlated by the Van't Hoff and Arrhenius equations respectively.; A single column pressure swing adsorption (PSA) unit has been designed and constructed to study the separation of air on carbon molecular sieves (CMS), 4A and 5A zeolites. The effect of various operating parameters on the performance of the unit is reported. The results from the analysis of PSA air separation on CMS show that a fairly high purity nitrogen product ({dollar}>{dollar} 98%) can be easily obtained. Experimental studies of PSA air separation on 5A-zeolite reveal that efficient separation can be achieved to yield a oxygen product containing 4-5% residual nitrogen. In case of 4A-zeolite using oxygen as purge the results show that a product containing 88% oxygen can be obtained. If nitrogen is used as purge, for the production of nitrogen on 4A-zeolite a product concentration containing 0.8% oxygen can be achieved. It was observed that an increase in purge to feed ratio, L/v{dollar}sb{lcub}rm H{rcub}{dollar} ratio and desorption time increase the product purity. On the other hand pressure ratio and cycle time shows some optimum values for all three systems.; The theoretical model of Farooq and Ruthven (69) was used after minor modification to predict the results for air separation on carbon molecular sieve. The model predictions agree reasonably well with the experimental data.