Adsorptive Desulfurization of Liquid Fuels at Elevated Temperatures Using Metal Exchanged Zeolite Y

Abstract

It has long been known that the ability of adsorptive methods to remove sulfur from transportation fuels at room temperature is limited by the competition of aromatic hydrocarbons and organosulfur compounds for the active sites of the adsorbent. In an effort to overcome these limitations, we studied adsorptive desulfurization at temperatures substantially higher than those considered by previous investigators. Na-Y and Cu-exchanged Na-Y (CuNa-Y) zeolites were used to remove sulfur from model fuels and a JP-8 fuel at temperatures up to 180 °C. Batch desulfurization and temperature-programmed desorption experiments with model fuels containing 3-methyl-benzothiophene (3-MBT) and dodecane showed that 3-MBT removal was strongly dependent on treatment temperature and involved weak physisorption bonds with Na, weak interactions with Cu sites at 30 or 80 °C, and strong chemisorption (S–Cu bonding) at 130 or 180 °C. Overcoming the competition that favors the adsorption of aromatics at low temperatures, the formati...