Competitive adsorption of C8 aromatics and toluene on KY and KBaX zeolites

Abstract

Liquid phase adsoiption of four isomers of C8 aromatics (p-xylene, mxylene, o-xylene, and ethylbenzene) with toluene as a desorbent on KY and KBaX zeolites at constant temperature was studied. Effects of each C8 aromatic concentration, operating temperature, and water content in the zeolites on the adsorption of each C8 aromatic were investigated. At high concentration, both zeolites adsorbed preferentially p-xylene, followed by ethylbenzene, m-xylene, and o-xylene at the studied water contents and temperatures. However, at low concentration, although the zeolites also adsorbed p-xylene the most, no definite trend was observed for the other aromatics. Additionally, KY zeolite had higher capacity and p-xylene selectivity than KBaX zeolite over the range of concentration. As the operating temperature increased, the zeolite capacity and p-xylene selectivity decreased. Moreover, the higher water content in the zeolite, the lower zeolite capacity and p-xylene selectivity. The statistical model provided good agreement to the single component adsorption data. In addition, the selectivity from multicomponent pulse tests on KY zeolite was higher than that from the single component result.