Sulfur-tolerant noble metal catalysts for reformulating diesel oils

Bimetallic Pd-Pt catalyst supported on ytterbium modified USY zeolite showed excellent hydrodesulfurization (HDS) and hydrodearomatization (HDA) activity, and showed high sulfur and nitrogen tolerance when used to reformulate hydrotreated diesel oils; sulfur reduction from 263 ppm to less than 20 ppm, and aromatics reduction from 26% to less than 5 %(di+ aromatics <1%) after a time on stream of 192 h at a hydrogen pressure of 3.9 MPa at 553 K and WHSV=4h(-1). Regarding industrial applications, we prepared the catalysts in extrudated form, i.e., Pd-Pt/Yb-USY-Al2O3 etc., which parallels the conditions employed in a commercial operation. The catalytic performances of these manufactured catalysts, including HDS and HDA activity and life, were confirmed during the time on stream of 2700 h in reformulating a diesel oil (S=429 ppm) in a bench-. scale high-pressure plant operated at 4.9 MPa and LHSV=2 h(-1).