| 摘要 |
<p>A catalyst containing an overlayer of a catalytic promoter on a porous refractory support containing an underbedded Group VIII metal-containing component. The catalyst is prepared by sequential incorporation of the Group VIII metal followed by the additional catalytic promoter component, usually a Group VIB metal, with the porous refractory oxide support. Underbedded nickel components on the catalyst are characterized by a unique Raman spectrum exhibiting Raman bands in the region of about 240 cm-1 to about 250 cm-1 and in the region of about 595 cm-1 to about 605 cm-1. The catalyst has a MoO¿3?/NiO weight ratio less than 6 to 1 and more than 4 weight percent of NiO. The catalyst is prepared by first producing a calcined particulate containing a group VIII metal component and a refractory oxide and, subsequently, adding a promoter, such as a group VIB metal component, and then recalcining the so obtained particulate composition. Preferred promoters are molybdenum and phosphorous compounds. The preferred composition is Ni-P-Mo oxides on alumina. The catalyst is especially useful for simultaneous hydrodenitrogenation and hydrodesulfurization of a gas oil, particularly when the refractory oxide support has a narrow pore size distribution.</p> |
