Bio-oil from Sawdust: Effect of Operating Parameters on the Yield and Quality of Pyrolysis Products

Abstract

This study investigated the effects of the pyrolysis temperature, feedstock particle size, and vapor residence time on the distribution and quality of liquid and char products from pyrolysis of sawdust in a fluidized-bed reactor. Sawdust and char samples were characterized with elemental and thermogravimetric analyses. Liquid bio-oil sample characterization was performed by Karl Fischer titration, elemental analysis, and gas chromatography–mass spectrometry (GC–MS). The bio-oil yield appeared to be maximized (≈62 wt %) at 500 °C, and the highest concentration of phenols was also produced at this temperature. Both the pyrolysis temperature and sawdust particle size had significant effects on the water content of the bio-oil with the water content being minimized at 500 °C. The yield of bio-oil showed a decreasing trend as the sawdust particle size was increased mainly because of the lower heating rate of larger sawdust particles. The effect of the residence time on the pyrolysis product distributions and their elemental compositions was negligible.