EQUILIBRIUM ADSORPTION DATA FROM BREAKTHROUGH CURVES WITH VARIABLE VELOCITY AND PRESSURE

In the framework of modeling PSA processes, column dynamics for the ad sorption of mixtures of helium and carbon dioxide on activated carbon has been investigated under conditions where both flow rate and column pressure vary due to adsorption. A model has been developed based on the usual approximations of local equilibrium and isothermal condition s but allowing for changes in flow rate as well as column pressure. Ex perimental breakthrough curves were measured up to 27 kPa, correspondi ng to 20 mol% carbon dioxide. Good agreement between model and experim ental curves was obtained up to 6 kPa and fair agreement up to 27 kPa carbon dioxide partial pressure. Adsorption isotherm data, required in the model calculations, have been obtained from these experimental st ep responses. These results are in good agreement with experimental eq uilibrium adsorption data obtained from both a static volumetric metho d and a gravimetric method.