MEASUREMENT OF THE SINGLE-COMPONENT ADSORPTION-KINETICS OF ETHANE, BUTANE, AND PENTANE ONTO ACTIVATED CARBON USING A DIFFERENTIAL ADSORPTION BED

The transient uptake of three paraffins onto a commercially available activated carbon has been studied by using the differential adsorption bed (DAB) technique, first reported by Carlson and Dranoff (1985), and a gravimetric method. A model describing adsorption in a single bimodal adsorbent particle was developed to analyze the experimental uptake data. The model accounts for the effects of macropore, solid, and micropore diffusion. The controlling mechanisms for the observed global uptake were identified by using experimental data measured for a wide range of conditions, and particle geometries and the appropriate parameters extracted. Diffusivities were determined at temperatures between 10 and 60-degrees-C. A macropore tortuosity factor of 8 was measured for the activated carbon used. For adsorption of ethane using commercially available 1/16-in. extrudate pellets, the mechanisms of pore, solid, and micropore diffusion were identified as important. Similar mechanisms were observed for n-butane and n-pentane adsorption. Good agreement between model predictions and experimental data was found over the broad range of conditions studied.