Light straight-run gas oil hydrotreatment over sulfided CoMoP/Al_2O_3-USY zeolite catalysts

摘要

A1_2O_3 supports were modified by integrating USY zeolites (13.6 wt.%) of various nominal SiO_2/ A1_2O_3 molar ratios (30-80).The obtained hybrid solids calcined at 500 deg C were impregnated at incipient wetness with a Co-Mo-P solution.After sulfiding with CS_2-spiked naphtha (at 230 deg C,5.5 MPa and LHSV=3 h~(-1)) the corresponding catalysts were tested in light straight-run gas oil hydrotreatment at industrially relevant operating conditions.The catalyst containing zeolite of the highest SiO_2/Al_2O_3 molar ratio (80) showed very high hydrodesulfurization activity.Operating at 360 deg C,5.5 MPa and LHSV=2.5 h~(-1),ultra-low sulfur diesel (-50 ppm S) could be obtained over that material,from a feedstock of 10,400 ppm S.Medium-strong acidity could be playing an important role on this behaviour by promoting isomerization of sterically hindered organo-sulfur compounds to more favorable configurations.Moreover,hydrodearomatization and hydrodenitrogenation were also enhanced by addition of that high-silica zeolite.