Purification of distilled coke oven benzene by distillation with added hydrocarbon material

Claim 1

IN A PROCESS FOR THE PURIFICATION OF DISTILLED COKE-OVEN BENZENE WHICH CONTAINS A SMALL AMOUNT OF NON-AROMATIC HYDROCARBON IMPURITIES HIGHER BOILING THAN BENZENE AND SUBSTANTIALLY INSEPARABLE THEREFROM BY SIMPLE DISTILLATION WHEREIN SAID BENZENE IS DISTILLED IN A FRACTIONAL DISTILLATION ZONE ADMIXED WITH ADDED NON-AROMATIC HYDROCARBON MATERIAL, SAID HYDROCARBON MATERIAL BOILING NORMALLY BETWEEN 75* AND 85* C. AND BEING ADDED IN AN AMOUNT IN EXCESS OF THAT REQUIRED TO FORM AN AZEOTROPE WITH SAID BENZENE, WHEREIN AN AZEOTROPE OF BENZENE AND SAID ADDED HYDROCARBON MATERIAL IS REMOVED FROM SAID DISTILLATION ZONE AS AN OVERHEAD FRACTION, AND WHEREIN THE HIGH BOILING IMPURITIES AND AT LEAST A PORTION OF THE EXCESS ADDED HYDROCARBON MATERIAL ARE REMOVED FROM THE DISTILLATION ZONE AS A DISTILLATION RESIDUE; THE IMPROVEMENT WHICH COMPRISES DISTILLING SAID AZEOTROPE OF BENZENE AND SAID ADDED HYDROCARBON MATERIAL IN A SECOND FRACTIONAL DISTILLATION ZONE IN THE PRESENCE OF AN AZEOTROPIC AGENT COMPRISING PREDOMINANTLY METHANOL, REMOVING FROM SAID SECOND DISTILLATION ZONE PURIFIED BENZENE AS A DISTILLATION RESIDUE REMOVING FROM SAID SECOND DISTILLATION ZONE AN AZEOTROPE OF SAID ADDED HYDROCARBON MATERIAL AND METHONOL AS AN OVERHEAD FRACTION, SEPARATING THE OVERHEAD FRACTION FROM SAID SECOND DISTILLATION ZONE INTO A METHANOL-RICH PHASE AND AN ADDED HYDROCARBON-RICH PHASE SOLELY BY COOLING, PASSING SAID METHANOL-RICH PHASE DIRECTLY TO SAID SECOND DISTILLATION ZONE AS AT LEAST A PORTION OF THE AZEOTROPIC AGENT EMPLOYED THEREIN, DISTILLING SAID HYDROCARBON-RICH PHASE IN A THIRD FRACTIONAL DISTILLATION ZONE TO YIELD SUBSTANTIALLY PURE HYDROCARBON MATERIAL, AND PASSING SAID HYDROCARBON MATERIAL TO THE FIRST MENTIONED DISTILLATION ZONE AS AT LEAST A PORTION OF THE HYDROCARBON MATERIAL ADDED TO SAID BENZENE TO FORM AN AZEOTROPE.