Smith MW (Dstl), Neininger E, Smith AG & Taylor K.
The use of computational fluid dynamics to model adsorption in activated carbon filters
Publication: Carbon 2006, The International Carbon Conference, Aberdeen
Computational fluid dynamics (CFD) offers a powerful method for studying flow distribution and adsorption in activated carbon filters. A model has been developed based on proprietary software (PHOENICS, CHAM Ltd, UK), with a front end enabling user input of filter dimensions and test conditions. The filter geometry and adsorbent physical properties determine the flow distribution within the filter, onto which adsorption phenomena are superimposed. At each cell within the computer generated grid, adsorption is modelled using experimental adsorption isotherm data to derive the capacity, with the adsorption kinetics assumed to follow a linear driving force algorithm. Experimental data has been acquired for breakthrough of pentane vapour through BPL carbon in a dry airstream, and this has been used for validation. The model has been shown to be capable of reproducing the effects of changing bed depths and flow rates on the breakthrough time, potentially offering a valuable filter design tool. The model is being developed to enable study of variable influent flow and concentration, conditions which are difficult and costly to replicate experimentally. Preliminary studies have also commenced to incorporate the effects of water vapour on filter performance, through adjustment of the capacity and kinetic terms in the model.
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