Azeotropic extractive distillation for enhanced methanol refinement

Abstract

Systems and processes for purifying a crude methanol stream including obtaining a crude methanol feedstock comprising methanol, water, acetone, methyl formate, and optionally one or more of ethanol, propanol, and butanol. The crude methanol is contacted with a glycol, a glycerol, or a mixture of glycols in an azeotropic distillation column to recover a first overhead stream comprising the acetone and methyl formate and a first bottoms stream comprising the glycol or glycerol, water, methanol, and, when contained in the feed, the ethanol, propanol and butanol. The first bottoms stream is then separated, in some embodiments, in a dividing wall distillation column to recover a second overhead stream comprising methanol and water, a second bottoms stream comprising the glycol or glycerol, a side draw stream comprising water and, when contained in the feed, the ethanol, propanol and butanol.

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