Effective Phase Separation of Biomass Pyrolysis Oils by Adding Aqueous Salt Solutions

Abstract

Effective separation methods must be developed to generate fractions of similar polarity and to concentrate the undistillable compounds before bio-oils are to be a source of chemicals production. Phase separation is one effective pathway to realize initial separation of bio-oil. By adding a little salt (3 wt % of bio-oil) or aqueous salt solution (10 wt % of bio-oil) including LiCl, CaCl2, FeCl3, (NH4)SO4, K2CO3, and Fe(NO3)3, the pyrolysis bio-oil of rice husk would quickly form two phases (40−80 wt % of the upper phase, 20−60 wt % of the bottom phase). On the basis of elemental analysis, 13C NMR integrations and GC/MS analysis, it has been demonstrated that some major components in the bio-oil are concentrated in upper/bottom phases respectively. The upper layers exhibit high contents of water, acetic acid, and water-soluble compounds; low density, viscosity, and calorific values; and high distillable substances (up to 65%). The bottom layer consists of low water content, high lignin-pyrolysis compounds, and low distillable substances (<10%), with high viscosity and calorific values. The physiochemical properties of two phases from the phase separation depend on the nature and dosage of salt added.

Water extraction of pyrolysis oil: The first step for the recovery of renewable chemicals

“…Some solvents used in pyrolysis oil analysis are pentane (Pütün et al, 1999), toluene, methanol, diethyl ether, n-hexane, dichloromethane, andwater (Garcia-Perez et al, 2007;Javaid et al, 2010;Oasmaa et al, 2003;Sipilä et al, 1998). A blend of fatty acid-methyl esters and ethyl acetate (Lian et al, 2010) and inorganic salt solutions (Song et al, 2009) can also be applied. Among those solvents, water is the cheapest one.…”

Mass production of chemicals from biomass-derived oil by directly atmospheric distillation coupled with co-pyrolysis

“…Direct processing the raw bio-oil catalytically seemed to be unfavorable because severe coke deposition causes a rapid deactivation of catalysts at temperature over 353 K13. Several methods have been proposed to break the micro-emulsion of raw bio-oil, e.g., adding inorganic salts14 or a sufficient amount of water1516 at first, then the resulting two phases could be further treated to obtain respective target products. Such a pre-treatment simplifies the problem to some extent.…”

Separation of phenol-containing pyrolysis products using comprehensive two-dimensional chromatography with columns based on pyridinium ionic liquids

“…The first-dimension column was represented by the most universal HP-5. The second-dimension IL column was 2MPyC 9 . As was shown in our earlier study, this IL has high polarity and provides good separation of phenols [16].…”

“…At present, publications devoted to GCxGC analysis of the liquid products of pyrolysis of various coals [3,7] can be found in the literature. Due to increased interest in renewable fuel resources, the GCxGC analysis of BO is reported in a greater number of works [9][10][11][12][13][14]. These works deal with GCxGC analysis of components in the initial BO [9][10][11][12] and its fractions [11,14].…”