Patent ID: 8864981

Claim:
A process for preparing a rubber processing oil (RPO), having a total aromatics content of more than 50 wt %, (or an aromatic carbon content of more than 20 wt %), a polycyclic aromatic content of less than 3 wt %, an aniline point. that is lower than 80° C., a kinematic viscosity from 15 to 30 mm 2 /s at 100° C., and a flash point that is higher than 250° C., which comprises the steps of: (a) introducing a bottom stream from an atmospheric crude oil distillation column into a vacuum distillation column to yield (i) a light distillate oil stream, (ii) a medium distillate oil stream, (iii) a heavy distillate oil stream, and (vi) a vacuum residue stream, wherein the medium and heavy distillate oil streams are mixed to form a distillate mixture which has a boiling range from 390 to 620° C., with the proviso that the light distillate oil stream is not processed to prepare the RPO; (b) producing a first aromatics-rich extract from the distillate mixture through counter current solvent extraction with a first polar extractive solvent in a first extraction column operating at a top temperature of 90-120° C., a bottom temperature of 70-90° C. and a solvent-to-distillate mixture volume ratio of 1 0-2.0 wherein the first aromatics-rich extract is a bottom stream from the first extraction column; (c) producing a second aromatics-rich extract, from a deasphalted residual oil that is derived from the vacuum residue stream, through counter current solvent extraction with a second polar extractive solvent in a second extraction column operating at a top temperature of 100-140° C., a bottom temperature of 80-110° C. and a solvent-to-deasphalted residual oil (DAO) volume ratio of 2.0-4.0 wherein the second aromatics-rich extract is a bottom stream from the second extraction column; (d) mixing the first aromatics-rich extract and the second aromatics-rich extract to yield a mixture that is subject to solvent extraction with a third polar extractive solvent to yield a raffinate phase wherein the mixture has a first aromatics-.rich extract to second aromatics-rich extract volume ratio in the range of 80:20 to 60:40; and (e) removing the third polar extractive solvent from the raffinate phase to yield the RPO.