Extraction of polycyclic aromatic compounds from petroleum feedstocks using ionic liquids

A process for removing a polycyclic aromatic hydrocarbon compound from a vacuum gas oil comprising:

• (a) contacting the vacuum gas oil comprising the polycyclic aromatic hydrocarbon compound with a vacuum gas oil-immiscible phosphonium ionic liquid to produce a mixture comprising the vacuum gas oil, and the vacuum gas oil-immiscible phosphonium ionic liquid;
• (b) separating the mixture to produce a vacuum gas oil effluent and a vacuum gas oil-immiscible phosphonium ionic liquid effluent, the vacuum gas oil-immiscible phosphonium ionic liquid effluent comprising the polycyclic aromatic hydrocarbon compound;
• (c) washing at least a portion of the vacuum gas oil effluent with water to produce a washed vacuum gas oil stream and a spent water stream;
• (d) contacting the vacuum gas oil-immiscible phosphonium ionic liquid effluent with a regeneration solvent and separating the vacuum gas oil-immiscible phosphonium ionic liquid effluent from the regeneration solvent to produce an extract stream comprising the polycyclic aromatic hydrocarbon compound and a regenerated vacuum gas oil-immiscible phosphonium ionic liquid stream;
• and
• (e) drying at least a portion of at least one of the vacuum gas oil-immiscible phosphonium ionic liquid effluent;
• the spent water stream, and the regenerated vacuum gas oil-immiscible phosphonium ionic liquid stream to produce a dried vacuum gas oil-immiscible phosphonium ionic liquid stream.