Bio-oil yield and quality enhancement through fast pyrolysis and fractional condensation concepts

Document Type: Research Paper


1 Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de- Bellevue, Canada.

2 Research and Development Institute for the Agri-Environment (IRDA), Québec, Canada.


The influence of operating conditions on the yield and quality of bio-oil obtained from black spruce wood mixture was studied using an auger reactor. Fast pyrolysis optimization through response surface analysis was carried out with four variables: pyrolysis temperature, solids residence time, nitrogen flow, and temperature of first stage of condensation. The optimal conditions obtained for bio-oil production were 555°C, 129 s, 6.9 L/min, and 120°C, respectively. The product yields were 38.61 wt.% of biochar, 25.39 wt.% of liquid, and 36.52 wt.% of non-condensable gases. Two liquid products were produced at the exit of the two condensers, following the concept of fractional condensation. The oily phase yield recovered in the first condenser was 10.59 wt.%, with a 16.86 wt.% of moisture content. Physical properties of the oily phase were analyzed and compared with the ASTM standard D7544-12. Qualitative identification of chemical compounds was carried out for the oily phase which helped in pyrolysis optimization for the bio-oil production targeted towards its use as fuel in commercial burners. In addition, the oil produced here is one of the lowest in water and solids content, attributable to the unique feature of auger reactors without the need for additional treatments.

Graphical Abstract

Bio-oil yield and quality enhancement through fast pyrolysis and fractional condensation concepts


  • Pyrolysis optimization allows the production of bio-oil with low water content.
  • Two liquids were obtained in the condensers separately by fractional condensation.
  • Nitrogen flow and temperature of condenser affect the oily phase yield.
  • Nitrogen flow affects the moisture in oil due to the shorter vapor residence time.
  • Levoglucosan was the most abundant compound in the pyrolytic oil.


[15] ÉcoRessources, C.G.D., 2012. INVENTAIRE RÉGI Inventaire  régionalisé  des  biomasses  exploitables  pour  la production de bioénergies au Québec. Ministère des Ressources naturelles, Bureau de l’efficacité et de l’innovation énergétiques, Québec.