(70a) Study On Stability of Pyrolysis Bio-Oil From Torrefied Loblolly Pine

The unstable nature of pyrolysis oil produced from fast pyrolysis of biomass is one of the undesirable properties that limit its application. Mild thermal pretreatment, torrefaction, has been proven to be an effective approach to reduce oxygen content in bio-oil; however, its effect on bio-oil stability has not yet been investigated. In this study, bio-oils generated from torrefied loblolly pine were aged at both accelerated (80 °C for 24 hour) and natural (25 °C for 12 months) aging conditions and the resulting bio-oil was characterized by several wet-chemistry and analytical methods. In order to monitor the property change of bio-oil during natural aging, oil samples were taken every three months for characterization. These characterizations measured bio-oil properties including water content, viscosity, acidity, molecular weight distribution, chemical composition from solvent fractionation of bio-oil, and GC/MS quantification of pyrolysis marker compounds.  The preliminary results showed different aging behaviors among bio-oils under investigation; for instance less viscosity increase was observed for aged bio-oil from thermally pretreated loblolly pine when compared to that of non-treated one. By comparing these aging behaviors of bio-oils prepared from torrefied wood to those of non-treated wood, the effect of torrefaction on bio-oil stability can be elucidated as well as possible aging mechanisms.