Biomass & Bioenergy, Vol.83, 96-104, 2015
Bio-oil fractionation by temperature-swing extraction: Principle and application
Bio-oils produced by direct thermal liquefaction often contain heavy components that hinder their utilization as a liquefaction medium. This paper reports a new approach to fractionate the liquefaction bio-oil into a light and a heavy fraction based on solvent extraction and temperature-swing regeneration. This approach is based on hot extraction (T similar to 70 degrees C) of the light fraction of the oil with a suitable extraction solvent followed by cold (T similar to 25 degrees C) de-mixing of the light fraction and the extraction solvent. In this paper, we (i) illustrate the selection of the extraction solvent and define the solvent properties required, (ii) demonstrate the potential of multistage extraction/regeneration for the bio-oil produced by direct thermal liquefaction, (iii) extend the concept to fractionate a petroleum crude oil, (iv) discuss the theoretical basis of the fractionation using polymer solution theory and, finally, (v) show a low energy requirement of the extraction process by means of process simulation, i.e., an equivalent of similar to 1% of the biomass intake. (C) 2015 Elsevier Ltd. All rights reserved.