Liquid-Liquid Extraction – Acetic Acid

Koch Modular has extensive experience with the recovery and purification of acetic acid (and other carboxylic acids, such as formic acid and valeric acid) from aqueous streams using liquid-liquid extraction (LLE). We have pilot tested, designed and supplied multiple liquid-liquid extraction columns and systems to the biofuel, biochemical, petrochemical, pharmaceutical, and specialty chemical process industries; applications including processing waste water and fermentation broths.

If the aqueous feed contains < 30% acetic acid, liquid-liquid extraction is usually a more economical solution than distillation for removal and recovery of acetic acid because the operating costs associated with distilling away the water far outweigh the capital costs of the liquid-liquid extraction process equipment.

A typical acetic acid extraction system is shown in the Process Flow Diagram below and includes the extraction column, a steam stripper to recover solvent from the aqueous effluent (raffinate), and a distillation column to generate the purified acid while also recovering the solvent for recycle to the extraction column. When designing and supplying this type of an extraction system, Koch Modular looks to provide the most economical solution for the entire process by selecting the proper solvent to feed ratio and then optimizing the complete system.

Acetic Acid Extraction

Typical solvents used for acetic acid recovery via liquid-liquid extraction are ethyl acetate, isopropyl acetate, and MTBE.

Key aspects of Koch Modular’s experience with acetic acid are:

  • Developed Liquid-Liquid and Vapor-Liquid equilibrium data when necessary information was unavailable in the literature
  • Tested more than 15 different acetic acid aqueous streams in our pilot plant columns
  • Designed and supplied more than 10 commercial LLE columns and numerous systems for acetic acid extraction and recovery
  • Supplied high efficiency LLE columns which allow minimization of solvent usage and thus the most economical solutions
  • Recovered Acetic acid at greater than 99.5% purity
  • For fermentation broths where emulsification can be an issue, our KARR® Column is the best industrial solution – see attached photo of KARR® Column used in a demonstration plant for recovery of acetic acid from a fermentation broth.

KARR® Column Design – Carboxylic Acid Extraction from Broth

  • Diameter = 22” (D1)
  • Expanded Ends Diameter = 44” (D2)
  • Plate Stack = 38’-0” (A)
  • Overall Height = 50’-6” (B)

Carboxylic Acid Extraction from BrothCarboxylic Acid Extraction from Broth