Integrated process for the production of high quality lube oil blending stock

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an improved integrated process for the production of high quality lube oil blending stock from atmospheric fractionation residue and waste lubricant.
In marked contrast with U.
S.
Pat.
No.
4,818,368 (Kalnes et al), the process of the present invention provides an integrated process for the production of distillate hydrocarbon from atmospheric fractionation residue and waste lubricants by means of contacting the waste lubricant with a hot hydrogen-rich gaseous stream to increase the temperature of this feed stream to vaporize at least a portion of the distillable hydrocarbonaceous compounds, thereby producing a distillable hydrocarbonaceous stream which is immediately hydrogenated in an integrated hydrogenation zone.
The vaporization of the waste oil is also conducted in the presence of an asphalt residue which has undergone a deasphalting step to remove a hydrocarbon stream which will eventually become a lube oil blending stock and which asphalt residue is produced in the integrated process of the present invention.
This asphalt residue is also introduced in the hot flash separator to provide additional heat to the separation zone and under certain circumstances where a waste lubricant feed stream does not have an appreciable amount of liquid non-distillable compounds, the asphalt residue is utilized to flush the heavy non-distillables from the flash zone.
An example of this latter situation is when the waste lubricant stream comprises a very high percentage of distillable hydrocarbonaceous compounds and relatively small quantities of finely divided particulate matter or "solid" and essentially no liquid non-distillable component for use as a carrier to remove the solids from the flash zone.
When the non-distillable fraction is flushed with asphalt residue, the properties of the asphalt residue stream which is removed from the bottom of the flash zone are enhanced for use as an asphalt cement and thus provides a convenient utilization of the bottom stream