Adsorptive separation of meta-xylene from C8 aromatics |
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Authors: | Milad Rasouli Nakisa Yaghobi Sahar Chitsazan Mohammad Hossein Sayyar |
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Affiliation: | 1. Faculty of Chemical Engineering, Islamic Azad University, South Tehran Branch, P.O. Box 11365/4435, Tehran, Iran;2. Iran Polymer and Petrochemical Institute, P.O. Box 14965/115, Tehran, Iran;3. Pooshesh Fan Avar Pars Co., P.O. Box 14965/115, Tehran, Iran |
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Abstract: | Industrial adsorptive separation process for liquids is most successful when the involved species have very close boiling points, making distillation expensive or are thermally sensitive at convenient distillation temperatures. The adsorption process was studied for separating meta-xylene from a feed mixture containing all C8 aromatics on binder-free X and Y zeolites in the liquid phase. Zeolitic adsorbents with different SiO2/Al2O3 were synthesized by the hydrothermal method and ion-exchanged with alkaline metal cations like lithium, sodium and potassium. The adsorption process was carried out in a breakthrough system at temperature of 110–160 °C and pressure of 6–8 atm. The influence of adsorbent moisture content on the separation process was studied. The optimization of adsorption process was also investigated by the changing operation conditions. The isotherms for each isomer of C8 aromatics and the desorbent possess the adsorption characteristics of Langmuir type. The selectivity factor of meta-xylene and the saturation adsorption capacities of adsorbates were determined. It was observed that the selectivity of meta-xylene increased by sodium ion-exchanging of cationic sites in Y zeolite and the selectivity factor of meta-xylene/para-xylene, meta-xylene/ortho-xylene and meta-xylene/ethylbenzene in the optimum conditions was determined to be 2.62, 2.83 and 5.93, respectively. |
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Keywords: | Adsorptive separation Na&ndash Y zeolite Selectivity factor C8 aromatics |
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