Utilizing Liquid-Liquid Extraction (LLE) or Solvent Extraction (SX) in the Efficient Recovery and Purification of Biofuels & Bioproducts

D. Glatz, B. Cross
Koch Modular Process Systems,
United States

Keywords: fermentation broth, liquid-liquid extraction, solvent extraction


In recent years, there has been a large emphasis on the production of organic chemicals from biomass generated via processes such as fermentation. Most of these processes produce low concentrations of organic chemicals that are higher boiling than water, and as such, distillation is not a viable first step for the recovery and purification process. Liquid-Liquid Extraction (LLE) is an ideal unit operation for the removal of many of these compounds either directly from the broth itself (whole broth) or from the broth after some pre-treatment step to separate the less desirable components such as cell mass, lignin, etc. The selection of the column type is critical for optimizing the performance and cost for extraction processes. Many biomass feed solutions, especially those produced by fermentation processes or by algae ponds, demonstrate a tendency to emulsify easily upon contact and mixing with an organic solvent. Years of experience have proven that the reciprocating type agitation in a KARRĀ® extraction column is superior to either columns with rotating internals or non-agitated columns for systems with a tendency to emulsify. For systems that mix and separate easily (non-emulsifying), a column with rotating turbine-type impellors will provide the most efficient and economical solution. We intend to present the benefits and advantages of agitated extraction columns that use a reciprocating plate stack assembly and for columns that use rotating impellors. Real world examples of how each agitation type was selected and designed for different biomass processes will be presented.