Process for manufacturing high quality naphthenic base oils

A method of manufacturing a naphthenic base oil from a hydrocarbon feedstock having a boiling point higher than that of gasoline and containing heteroatom species and an aromatic material, comprising:

• (a) separating a light cycle oil and a slurry oil from oil fractions obtained through fluidized catalytic cracking;
• (b) separating the slurry oil separated in step (a) into a deasphalted oil and a pitch through solvent deasphalting;
• (c) hydrotreating the light cycle oil separated in step (a), the deasphalted oil separated in step (b), or a mixture thereof, using a hydrotreating catalyst to produce a hydrotreated oil fraction having a reduced amount of heteroatom species;
• (d) dewaxing the entire hydrotreated oil fraction, obtained, in step (c), using is dewaxing catalyst to produce a dewaxed oil fraction having a lowered pour point, the dewaxing catalyst comprising a support selected from the group consisting of molecular sieve, alumina and silica-alumina, and a combination of (i) Ni or Co,and (ii) Mo or W as a hydrogenation metal component;
• (e) hydrofinishing the dewaxed oil fraction, obtained in step (d), using a hydrofinishing catalyst to produce a hydrofinished oil fraction with the aromatic content thereof adjusted to comply with a product standard;
• and
• (f) separating the hydrofinished oil fraction, obtained in step (e), according to a range of viscosity,
• wherein steps (a) through (f) are carried out successively such that no hydroprocessig steps are conducted between the hydrotreating step (c) and the dewaxing step (d),
• wherein the light cycle oil separated in step (a), the deasphalted oil separated in step (b), or the mixture thereof has an aromatic content of 60 wt% or more,
• wherein the hydrotreated oil fraction in step (c) has a sulfur content of less than 200 ppm, a nitrogen content of less than 100 ppm, an aromatic content of less than 60 wt% and a poly-aromatic content of not more than 5%, and
• wherein the naphthenic base oil has a viscosity index of 85 or less, in which at least 30% of the carbon bonds thereof are of a naphthenic type according to ASTM D-2140, and has a naphthene content of 40 wt% or more.