Study of hydrodesulfurization of 4,6-DM-DBT over Pd supported on mesoporous USY zeolite

Two ultra-stable Y zeolites (USY550 and USY600) with mesoporous volumes of 0.15 and 0.25 cm3/g were prepared by steam dealumination at 550 and 600 °C, respectively. Pd catalysts were supported on γ-Al2O3, H-forms of zeolite Y (HY), mesoporous USY for hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene (4,6-DM-DBT). The 4,6-DM-DBT conversions over Pd/USY550 (85.7%) and Pd/USY600 (76.9%) are higher than over Pd/HY (43.7%) due to the facilitated mass transfer of 4,6-DM-DBT in the mesopores USY. The better HDS performance of Pd/USY than Pd/γ-Al2O3 is attributed to the stronger acidity of USY, as demonstrated by the stepwise temperature-programmed desorption of ammonia. Thermogravimetric and X-ray photoelectron spectroscopic analysis of the used catalysts showed that the poison of Pd particles over the supports by sulfur was responsible for the catalyst deactivation.

Dependence of the remaining sulfur content in 4,6-DM-DBT-hydrogenation system on reaction time over (■) Pd/USY550, () Pd/USY600, () Pd/HY, and () Pd/γ-Al2O3 catalysts at reaction temperature of 250 °C.Figure optionsDownload high-quality image (118 K)Download as PowerPoint slideFigure optionsDownload high-quality image (1 K)Download as PowerPoint slideFigure optionsDownload high-quality image (1 K)Download as PowerPoint slideFigure optionsDownload high-quality image (1 K)Download as PowerPoint slideHighlights
► Pd/USY exhibited high activity in HDS of 4,6-DM-DBT under the mild condition.
► The 4,6-DM-DBT conversion over Pd/USY550 is nearly 100%.
► Stability experiment over Pd/USY was also performed (175 h).