PRESSURE-DROP EFFECTS IN THE PRESSURIZATION AND BLOWDOWN STEPS OF PRESSURE SWING ADSORPTION

Linearization of Darcy's law for flowing through packed beds allows the incorporation of pressure drop into existing models for the non-constant pressure steps of PSA. Bed length and particle size appears as explicit variables whose effect can be studied. With rapid cycles pressure gradients do not have time to decay; therefore, pressure drop is obviously important. Shock wave behavior is observed for pressurization and an analysis based on material balances around the shock is given. Blowdown exhibits diffuse wave behavior. All solutions at the closed end reduce to limiting forms available in the literature. Further, blowdown solutions at large times indicate a non-uniform composition in the column, which mean that pressure drop effects are significant during blowdown even when conventional cycling time schemes are used.