Process for recovering refined ethyl alcohol by plural distillation

Claim 1

THE PROCESS OF PURIFYING A CRUDE ETHYL ALCOHOL PREPARED BY THE HYDRATION OF ETHYLENE IN THE PRESENCE OF A POLYBASIC MINERAL ACID-ACTING ACID AND WHEREIN SAID CRUDE ETHYL ALCOHOL CONTAINS ABOUT 5 PERCENT TO ABOUT 10 PERCENT BY WEIGH OF CHARACTERISTIC ORGANIC IMPURITIES INCLUDING ETHER, ALIPHATIC ALDEHYDE, ALIPHATIC KETONE AND ALIPHATIC ALCOHOL COMPOUNDS AND WHEREIN SECONDARY BUTYL ALCOHOL IS THE PRINCIPAL INDIVIDUAL ORGANIC IMPURITY PRESENT, ABOUT 20 PERCENT TO ABOUT 35 PERCENT BY WEIGHT OF WATER AND ABOUT 60 PERCENT TO ABOUT 75 PERCENT BY WEIGHT OF ETHYL ALCOHOL WHICH COMPRISES CONTINUOUSLY FEEDING THE CRUDE ETHYL ALCOHOL TO A FRACTIONAL DISTILLATION ZONE AT AN INTERMEDIATE POINT THEREOF, CONTINUOUSLY ADDING WATER TO THE FRACTIONAL DISTILLATION ZONE AT A POINT SUBSTANTIALLY ABOVE THAT AT WHICH THE CRUDE ETHYL ALCOHOL IS INTRODUCED TO MAINTAIN AN INTERNAL LIQUID REFLUX HAVING A WATER CONTENT IN THE RANGE OF 85 TO 99 MOLE PERCENT THROUGHOUT THE LIQUID PHASE IN THE FRACTIONAL DISTILLATION ZONE, DISTILLING FROM SAID CRUDE ETHYL ALCOHOL A VAPOROUS MIXTURE CONTAINING WATER AND SUBSTANTIALLY ALL THE ORGANIC IMPURITIES PRESENT IN THE CRUDE ETHYL ALCOHOL WHEREIN THE OVERHEAD VAPOROUS MIXTURE DISTILLED FROM THE CRUDE ETHYL ALCOHOL FLOWS COUNTERURRENT TO THE AQUEOUS REFLUX AT TEMPERATURES ABOVE THE BOILING POINT OF THE ALCOHOL, CONTINUOUSLY WITHDRAWING A DILUTE AQUEOUS SOLUTION OF ETHYL ALCOHOL SUBSTANTIALLY FREE OF ORGANIC IMPURITIES BUT CONTAINING SOME SECONDARY BUTYL ALCOHOL FROM A LOWER POINT OF SAID FRACTIONAL DISTILLATION ZONE, RECTIFYING THE WITHDRAWN AQUEOUS ETHYL ALCOHL IN A SECOND FRACTIONAL DISTILLATION ZONE, REMOVING FROM THE TOP OF SAID SECOND FRACTIONAL DISTILLATION ZONE REFINED ETHYL ALCOHOL OF THE ORDER OF 190-PROOF SUBSTANTIALLY FREE OF ORGANIC IMPURITIES, REMOVING A SIDE STREAM CONSISTING ESSENTIALLY OF SECONDARY BUTYL ALCOHOL, ETHYL ALCOHOL AND WATER FROM THE UPPER ORTION OF SAID SECOND FRACTIONAL DISTILLATION ZONE BUT AT A POINT SUBSTANTIALLY BELOW THAT AT WHICH THE REFINED ETHYL ALCOHOL IS REMOVED AND RECYCLING SAID SIDE STREAM TO THE FIRST FRACTIONAL DISTILLATION ZONE FOR REDISTILLATION THEREON.