Membrane extraction improves biofuel yield

Typically, the production of fuel-grade chemicals, such as butanol, from biomass fermentation processes involves low-yield batch processes and high energy costs. Now, researchers from Imperial College London (ICL; www.imperial.ac.uk), in partnership with bp plc (London; www.bp.com), have demonstrated a new membrane-based extraction process for biofuels that helps overcome these hurdles, reportedly boasting a 25% reduction in energy use and a tenfold increase in production yield. In typical biomass fermentation processes, the produced butanol contains water that must be removed, either through heterogeneous distillation (requiring an energy-intensive phase change) or batch liquid-liquid extraction, explains Ji Hoon Kim, ICL researcher and co-author of the study. “Our new membrane-extraction process can extract the produced biofuel from a fermentation broth using an extractant with a high partition coefficient, providing high recovery rates through a membrane without requiring phase change,” adds Kim. Since the extractant — an organic solvent based on 2-ethyl-1-hexanol — has around half the heat capacity of water and a higher boiling point than butanol, it does not require evaporating any water or extractant, meaning that the…