Liquid-Liquid Extraction of Bio-Oil Components

Increases in the world population and energy demand have raised the importance of developing sustainable energy resources. Utilizing bio-oil (pyrolysis oil) from biomass may alleviate global energy problems; however, wide applications of bio-oil are hampered by difficulties in attaining usable, high-quality bio-oil. Particularly, separating the aqueous phase and water-soluble compounds from crude bio-oil has not been effective. Bio-oil has high moisture content, low pH, high viscosity, and low heating value. Liquid-liquid extraction has been investigated in this work as a method to effectively separate the aqueous and organic phases of bio-oil. The effects of pH, ionic strength, and volume ratio of aqueous solutions used in liquid extraction on the separation of water and water-soluble species from bio-oil are being investigated. Results thus far show that, as the ionic strength of the aqueous solution is increased, more acidic compounds are selectively extracted from the bio-oil. This is desirable, as acidic components are utilized downstream for hydrogen production in bio-electrochemical cells. Results from a wide range of experimental variables will be reported. Furthermore, liquid-liquid extraction experiments using a centrifugal contactor for selected experimental conditions of volume ratio, pH, and ionic strength of the aqueous phase will be presented.