Patent ID: 7790943

Claim:
A process for removing benzene from a feedstock and recovering cyclohexane that comprises the steps of: (a) removing benzene from the feedstock by extractive distillation to yield purified benzene that comprises the steps of: (i) introducing the feedstock into a first portion of a first extractive distillation column (EDC) and introducing a first lean extractive distillation (ED) solvent into a second portion of the first EDC which is above the first portion; (ii) withdrawing a recovered hydrocarbons stream comprising C 7 and lighter non-aromatics from an overhead of the first EDC which is suitable for gasoline blending and collecting a first rich solvent stream C 6 and heavier aromatics, C 8 and heavier non-aromatics, and solvent from a bottom portion of first EDC; (iii) mixing the first rich solvent stream with a second rich solvent that is from a second extractive distillation column (EDC) and feeding the mixture to a first solvent recovery column (SRC) to recover hydrocarbons from an overhead of the first SRC and recycling lean solvent stream from a bottom of the first SRC to both the first EDC and second EDC; and (iv) transferring the recovered hydrocarbons stream to an azeotropic distillation column (ADC) to remove benzene/water and cyclohexane/water azeotropes from an overhead of the ADC that is recycled to the first SRC, to recover a benzene and cyclohexane mixture with reduced water levels from a side-cut of the ADC, and to withdraw remaining hydrocarbons from a bottom of the ADC wherein the remaining hydrocarbons are suitable for gasoline blending; (b) hydrogenating a portion of the purified benzene in a hydrogenation reactor to yield an effluent that contains a mixture of benzene and cyclohexane; and (c) purifying the effluent to produce a product stream containing purified cyclohexane comprises the steps of: (i) feeding the effluent containing a mixture of benzene and cyclohexane from the hydrogenation reactor to a first portion of a second extractive distillation column (EDC) and feeding a second lean extractive distillation (F,D) solvent to a second portion of the second EDC that is above the first portion; (ii) withdrawing purified cyclohexane from an overhead of the second EDC and withdrawing a second rich solvent containing benzene, cyclohexane, and solvent from a bottom of the second EDC; and (iii) transferring the second rich solvent to a solvent recovery column (SRC) to recover benzene and cyclohexane from an overhead of the SRC and to recycle lean solvent from a bottom of the SRC to the first EDC and the second EDC.