Systems and methods are provided for production of base stocks with a viscosity index of at least 120 and/or a sulfur content of 300 wppm or less and/or a kinematic viscosity at 100 C. of 3.0 cSt to 8.0 cSt by hydroconversion of a raffinate from aromatic extraction of a feed. The base stocks can further have a reduced content of 3+ ring naphthenes, such as 4.0 wt % or less, or 1.0 wt % or less. The base stocks can be produced by performing an elevated amount of feed conversion relative to 370 C. during hydroconversion of the raffinate, and optionally additional conversion during catalytic dewaxing of the hydroconverted raffinate. The base stocks can optionally be blended with additional base stocks and/or lubricant additives for production of lubricant compositions.

A method for re-refining used oils comprises contacting feedstock comprising purified used oil with extraction solvent to perform continuous liquid-liquid solvent extraction, to produce an extract stream comprising the extraction solvent and an extract dissolved in the extraction solvent. The feedstock and the extraction solvent are agitated by a variable speed agitator during the solvent extraction at a selected agitation speed. The extract is separated from the extraction solvent and subjected to a continuous flow liquid phase hydrogenation treatment to produce an oil product. A system for performing the method includes a purification unit for purifying the used oil; an extraction column for extracting the extract from the feedstock; and a continuous flow liquid phase hydrogenation unit. The extraction column comprises an agitator configured to agitate the feedstock and the extraction solvent flowing through the extraction column at a variable agitation speed.

A selective mid-distillate hydrotreating process is provided for production of hydrocarbon fuels with an ultra-low level of sulfur in which the initial hydrocarbon feedstock is introduced into to an aromatic extraction zone to produce an aromatic-lean fraction and an aromatic-rich fraction, which contain different classes of organosulfur compounds having different reactivities when subjected to hydrotreating reactions. The aromatic-lean fraction contains primarily labile heteroatom-containing compounds, and is passed to a first hydrotreating zone operating under mild conditions to remove the sulfur heteroatom from organosulfur hydrocarbon compounds. The aromatic-rich fraction contains primarily refractory heteroatom-containing compounds, including aromatic molecules such as certain benzothiophenes (e.g., long chain alkylated benzothiophenes), dibenzothiophene and alkyl derivatives, such as sterically hindered 4,6-dimethyldibenzothiophene, and is passed to a hydrotreating zone operating under relatively severe conditions to remove the heteroatom from sterically hindered refractory compounds.

Systems and processes for hydrotreating, splitting, and extracting a gasoil feed to produce a saturate-rich feedstock for olefin pyrolysis are provided. A gasoil feed is provided to a hydrotreating section to produce an ultralow sulfur distillate (ULSD) stream. The ULSD stream is provided to a splitter section to produce a light distillate stream and a heavy bottom stream. The light distillate stream is provided to an extraction section to produce an aromatic-rich extract phase and a saturate-rich raffinate phase. The raffinate phase is mixed with the heavy bottom stream to produce an olefin pyrolysis feedstock having a reduced BMCI as compared to the gasoil feed stream and the ULSD stream.

A process of producing Group III base oils, along with a naphtha product and diesel product, from whole waxy crude oil is provided. The inventive process omits the typical vacuum distillation stage and separations to form the typical cuts off of the vacuum tower. By selecting a waxy crude oil suitable for processing without separations, the crude oil may be hydroprocessed, dearomatized, dewaxed, and hydrofinished to produce a Group III base oil. Additionally, the dewaxing catalyst will isomerize the naphtha range molecules to increase the octane value to a suitable level for blending into gasoline and the diesel range molecules to reduce the diesel cloud point.

Naphthenic process oils are made by blending one or more naphthenic vacuum gas oils in one or more viscosity ranges with a high C.sub.A content distilled aromatic extract feedstock to provide at least one blended oil, and hydrotreating the at least one blended oil to provide an enhanced C.sub.A content naphthenic process oil. The order of the vacuum distillation and blending steps may be reversed.

Systems and methods are provided for production of base stocks with a viscosity index of at least 120 and/or a sulfur content of 300 wppm or less and/or a kinematic viscosity at 100 C. of 3.0 cSt to 8.0 cSt by hydroconversion of a raffinate from aromatic extraction of a feed. The base stocks can further have a reduced content of 3+ ring naphthenes, such as 4.0 wt % or less, or 1.0 wt % or less. The base stocks can be produced by performing an elevated amount of feed conversion relative to 370 C. during hydroconversion of the raffinate, and optionally additional conversion during catalytic dewaxing of the hydroconverted raffinate. The base stocks can optionally be blended with additional base stocks and/or lubricant additives for production of lubricant compositions.

Deep desulfurization of hydrocarbon feeds containing undesired organosulfur compounds to produce a hydrocarbon product having low levels of sulfur, i.e., 15 ppmw or less of sulfur, is achieved by hydrotreating the feed under mild conditions, and separating the hydrotreated effluent into an aromatic-rich fraction which contains a substantial amount of the aromatic refractory and sterically hindered sulfur-containing compounds, and an aromatic-lean fraction. The aromatic-rich fraction is contacted with isomerization catalyst, and the isomerized aromatic-rich fraction is recycled to the mild hydrotreating process.

A method for re-refining used oils comprises contacting feedstock comprising purified used oil with extraction solvent to perform continuous liquid-liquid solvent extraction, to produce an extract stream comprising the extraction solvent and an extract dissolved in the extraction solvent. The feedstock and the extraction solvent are agitated by a variable speed agitator during the solvent extraction at a selected agitation speed. The extract is separated from the extraction solvent and subjected to a continuous flow liquid phase hydrogenation treatment to produce an oil product. A system for performing the method includes a purification unit for purifying the used oil; an extraction column for extracting the extract from the feedstock; and a continuous flow liquid phase hydrogenation unit. The extraction column comprises an agitator configured to agitate the feedstock and the extraction solvent flowing through the extraction column at a variable agitation speed.

The present disclosure discloses a process for obtaining an aromatic lean stream and an aromatic rich stream from a hydrocarbon feed, the process comprising: (a) obtaining a hydrocarbon feed; and (b) contacting the hydrocarbon feed with a solvent selected from a group consisting of alkyl aromatic hydrophilic polyethylene oxide, polyethylene glycols, and combinations thereof to obtain an aromatic lean stream and an aromatic rich stream. It further discloses a simultaneous process to obtain an aromatic lean stream and an aromatic rich stream. The present disclosure also discloses a process for obtaining de-aromatized kerosene from a hydrocarbon feed. Additionally, the present disclosure discloses a process for obtaining BTX from a hydrocarbon feed.