WAVE-FRONT ANALYSIS FOR DESIGN OF FIXED-BED ADSORBERS

Prevailing approaches utilize empty bed contact time (or EBCT) as the primary design parameter for fixed-bed adsorbers; this despite studies that demonstrate that wave front velocity analysis is a mathematicall y more straightforward approach for adsorber design and operation, The re are a number of assumptions inherent in the wave front approach, ho wever, that generate important design questions related to the timing and nature of the development of the constant pattern. These questions are addressed in a numerical study of the rate of movement of the flu id phase concentration wave front as the constant pattern is approache d in a granular activated carbon bed. Analyses for two organic compoun ds of dissimilar adsorption characteristics, trichloroethylene and par a-bromophenol, revealed highly variant approaches to the constant patt ern condition, More importantly, the exercise demonstrates how dynamic model simulations can insure that verification studies at the pilot s cale are properly designed to obtain a correct quantitative descriptio n of the constant pattern mass transfer zone.