Ethanol Production by Extractive Fermentation: A Novel Membrane Extraction Technique
A new type of membrane extraction for in situ removal of ethanol from fermentation broth is presented. Aqueous solutions of Ethylene or Propylene Glycol are used as extractants. The extractant and the broth are separated by a microporous hydrophobic membrane which is not penetrated by the broth or by the extractant. As a consequence a thin gas layer, essentially air, is inmobilized within the membrane pores and separates the two liquid phases (gas membrane). Glycols lower the relative volatility of ethanol with respect to water and as a consequence ethanol vapours preferentially diffuse through the stagnant gas layer.
KeywordsPropylene Glycol Membrane Extraction Hydrophobic Membrane Membrane Distillation Extractive Distillation
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