Ethanol refining process using intermediate reboiler

摘要

The present invention relates to processes for producing and recovering ethanol using an intermediate reboiler. An intermediate stream may be withdrawn from a removal zone of a distillation column and recirculated through the intermediate reboiler to the distillation column. The distillation column may also comprise a bottoms reboiler.

主权项

1. A process for refining ethanol from a dilute acid stream, comprising:
introducing the dilute acid stream to an inlet zone of a distillation column to yield an overhead comprising ethanol; wherein the dilute acid stream comprises from 0.1 to 10 wt. % acid; recirculating an intermediate stream, withdrawn from a removal zone, by passing the intermediate stream through an intermediate reboiler and returning the intermediate stream to the distillation column at or adjacent to the removal zone to supply heat to the distillation column, heating the distillation column below the removal zone with a bottoms reboiler and withdrawing a residue therefrom, wherein the residue comprises water and substantially all of the acid from the dilute acid stream; and recovering an ethanol product from the overhead; wherein the intermediate reboiler is operated under non-esterification conditions, wherein less than 1000 ppm of ethyl acetate is formed in the intermediate reboiler.