Exxonmobil Research and Engineering Company

Exxonmobil Technology and Engineering Company

Jason T Calla

Gary Paul Schleicher

Eric D Joseck

Will G Fisher, Jr

Seth D Fortney

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&#xb0; 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&#xb0; 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.

Raffinate hydroconversion for production of high performance base stocks

Base stocks having Group III/III+ characteristics are prepared from certain advantageous crude oils via simplified process configurations and/or under less severe process conditions. Crude oils comprising a vacuum gas oil (VGO) fraction having a ratio of a sum of paraffin content plus 1-Ring species content to multi-ring species content that is greater than or equal to about 1.5 are advantageous in this context. Other parameters such as API gravity and crude compositional ranges may also be considered for identifying advantageous crudes. In some instances, advantageous crudes are processed into Group III base stocks via a process configuration in which the crude oil is directly supplied to a hydroprocessing unit.

Process for production of base stocks

Systems and methods are provided for hydroprocessing a petroleum fraction, such as a bottoms fraction from a fuels hydrocracking process, to generate a lubricant base oil. A fuels hydrocracking process typically has less stringent requirements for the sulfur and nitrogen content of a feed as compared to a lubricant base oil. Additionally, depending on the nature of the feed for the fuels hydrocracking process, the bottoms fraction may contain a relatively high level of aromatics compounds. The aromatic content of such a petroleum fraction can be reduced using a aromatic saturation stage with multiple catalyst beds, or alternatively using a reactor (or reactors) with multiple aromatic saturation stages. The catalysts in the various beds or stages can be selected to provide different types of aromatic saturation activity. An initial bed or stage can provide activity for saturation of 1-ring aromatics in the petroleum fraction. One or more subsequent beds or stages, operating at successively lower temperature, can then be used to reduce the multiple-ring aromatic content of the petroleum fraction.

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Raritan, NJ, United States of America

Jason T Calla