Multicomponent adsorption modeling for separation of BTX in packed bed

This study focuses on the simulation of packed bed adsorber for separation of BTX (benzene, toluene, m xylene) in presence of other molecules such as CO2, H2O and H2S using Aspen Adsim^® package. The breakthrough curves were generated for the silica based adsorbent (mKIT-6) which is surface modified KIT-6 using 0.006% 3-aminopropyl triethoxysilane. The surface modifications were performed with the intent of maximizing the aromatic adsorption and minimizing the other component adsorption. The experimental adsorption isotherm data of pure BTX and the other components for mKIT-6 adsorbents were generated using a gas phase gravimetric analyzer. A comparative adsorption on mKIT-6 indicates adsorption in the following order Xylene > Toluene >Benzene > H2O > H2S > CO2. The presence of contaminants on the BTX breakthrough was found to be insignificant due to their low adsorption on mKIT-6. The competitive adsorption of BTX and other molecules were accounted through the Ideal Adsorption Solution Theory model (IAST). With the column cut-off being 20% of the inlet concentration of the toluene molecule, a reasonable cut-off duration of near 38 hours could be achieved for a 10m by 3m column size.