Alcohol purification process

Claim 1

IN A METHOD FOR PURIFYING AND REFINING CRUDE AQUEOUS ETHANOL PRODUCED BY THE HYDRATION OF AN ETHYLENE CONTAINING STREAM, SAID CRUDE ETHANOL CONTAINING BOTH LOWER BOILING IMPURITIES, INCLUDING UNSTABLE POLYMERIC OILS BOILING IMPURITIES, INCLUDING UNSTABLE POLYMERIC OILS WHICH UNDERGO DECOMPOSITION UNDER DISTILLATION CONDITIONS, WHICH COMPRISES THE STEPS OF CONTINUOUSLY PASSING SAID CRUDE AQUEOUS ETHANOL INTO A FRACTIONAL EXTRACTIVE DISTILLATION ZONE, CONTINUOUSLY FEEDING WATER INTO SAID FRACTIONAL EXTRACTIVE DISTILLATION ZONE AT A POINT ABOVE THE AQUEOUS ETHANOL FEED STREAM, MAINTAINING AN INTERNAL LIQUID REFLUX HAVING AN ETHANOL CONTENT OF 5 TO 40 WEIGHT PERCENT WITHIN THE ZONE BELOW THE WATER FEED POINT, CONTINUOUSLY REMOVING FROM THE UPPER PORTION OF SAID EXTRACTIVE DISTILLATION ZONE, A STREAM CONTAINING ORGANIC IMPURITIES INCLUDING BOTH LOWER AND HIGHER BOILING MATERIALS, CONTINUOUSLY REMOVING FROM THE LOWER PORTION OF SAID EXTRACTIVE DISTILLATION ZONE A DILUTE AQUEOUS ETHANOL STREAM, PASSING SAID AQUEOUS ETHANOL TO A CONCENTRATING FRACTIONAL DISTILLATION ZONE, AND REMOVING FROM AN UPPER PORTION OF SAID CONCENTRATING DISTILLATION ZONE A STREAM OF CONCENTRATED ETHANOL, THE IMPROVEMENT WHICH COMPRISES THE STEPS OF SUBJECTING SAID CRUDE ETHANOL CONTAINING STREAM TO A PRELIMINARY FRACTIONAL DISTILLATION BY PASSING SAID STREAM INTO A FRACTIONAL DISTILLATION ZONE, CONTINUOUSLY REMOVING FROM THE UPPER PORTION OF SAID FRACTIONAL DISTILLATION ZONE, A STREAM CONTAINING SUBSTANTIALLY ALL OF THE ETHANOL AT A CONCENTRATION OF 85 TO 95 WEIGHT PERCENT OF TOTAL ETHANOL PLUS WATER, AND RELATIVELY FREE OF HIGHER BOILING UNSTABLE POLYMERIC OILS WHICH UNDERGO DECOMPOSITION UNDER FINAL RECTIFICATION CONDITIONS, PASSING SAID RECOVERED ETHANOL STREAM TO A SECOND FRACTIONAL DISTILLATION ZONE, REMOVING FROM THE UPPER PORTION OF SAID SECOND FRACTIONAL DISTILLATION ZONE A STREAM CONTAINING LOWER BOILING IMPURITIES INCLUDING SUBSTANTIALLY ALL OF THE DIETHYL ETHER, REMOVING FROM THE LOWER PORTION OF SAID SECOND FRACTIONAL DISTILLATION ZONE AN ETHER-FREE AQUEOUS ETHANOL STREAM, AND THEN PASSING SAID ETHER-FREE ETHANOL STREAM INTO THE ABOVE DESCRIBED FRACTIONAL EXTRACTIVE DISTILLATION ZONE.