Separation and Purification Technology, Vol.86, 157-170, 2012
Recovery of renewable phenolic fraction from pyrolysis oil
The aim of this work was to develop a separation process for phenolic fraction recovery from various bio-oils, produced by fast pyrolysis process of wood and forest residues in the framework of the EU Project BIOCOUP. Two slightly different schemes were introduced, namely the first one starting with an aqueous extraction of pyrolysis oil and the second one with the simultaneous use of a hydrophobic-polar solvent and anti-solvent in the extraction of bio-oil. In both cases the distribution coefficients of phenolic components between the phases as well as extraction factors for major separation stages are presented. Different aqueous solutions were applied and alkali solution was found to be more efficient in comparison to water or aqueous NaHSO3 solution. From various hydrophobic-polar solvents which had been tested, methyl isobutyl ketone (MIBK) was shown to be the most efficient solvent for extraction of phenolics from bio-oil in combination with 0.1 or 0.5 M aqueous NaOH solution, followed by butyl acetate. (C) 2011 Elsevier B.V. All rights reserved.
Keywords:Pyrolysis oil;Phenolic fraction;Aqueous extraction;Solvent-anti-solvent technique;Distribution coefficient