Two-Stage Sequential Adsorption System for Denitrogenation and Desulfurization of Model Diesel Oil over Ion-Exchanged Y Zeolites

Abstract

This work focused on adsorptive desulfurization (ADS) and denitrogenation (ADN) in single- and two-stage systems. Na-Y zeolite possessed the best 4,6-DMDBT and DBT adsorption performances. La-Y zeolite exhibited the best ADN efficiency. The impact of nitrogen compounds and aromatics on ADS capacity and the impact of sulfur compounds and aromatics on ADN ability over ion-exchanged Y zeolite were evaluated in the single-stage system. The nitrogen compounds not only have the ability to compete, but they also have a higher absorbability than sulfur compounds. The sequential adsorption in a two-stage system was proposed to enhance ADS ability. The first stage contained La-Y for ADN, and the second stage contained Na-Y for ADS. It was found to successfully increase the breakthrough capacity of all compounds by 40% compared with the single-stage system. This two-stage sequential system is a suitable route for the elimination of sulfur and nitrogen content in diesel oil.