Manufacturing of Extra Neutral Alcohol
The concentrated rectified spirit from Pre-Rectifier column is fed to the Extractive Distillation column. Dilution water is fed on the top most of the column with a dilution ratio of 1:9. Extractive Distillation column serves to remove the impurities based on the principles of Hydro-Extraction. The water is fed to the column in such a way that it selects the higher alcohols and other impurities to move upwards and extracts ethanol down. The top vapours of the columns are condensed and feed to the recovery column.
The purified dilute ethanol is removed from the bottom of the column and feed to the rectification column, which concentrates ethanol to 96% v/v. Rectifier Column operates under pressure and condensing steam provides energy to this column through a vertical Thermosyphon reboiler. ENA draw is taken out from appropriate upper trays and fed to Simmering Column after cooling. Simmering Column is operated under high reflux for better separation of methanol and di-acetyls. Final ENA product draw is taken from the bottom of this column. The spent lees of the column are recycled as dilution water after a part of it is purged.
Lower side draw streams are taken from rectification column to avoid fusel oil build up in the column. These streams are sent to the Recovery Column where fusel oils are concentrated and then sent to decanter where these streams are diluted with water and fusel oil rich layer is separated. Washings are sent back to the column to recover alcohol. An impure spirit cut will be taken from top of this column.