An experimental study to investigate the effect of torrefaction temperature and time on pyrolysis of centimeter-scale pine wood particles

Published Date
1 December 2016, Vol.153:74–80, doi:10.1016/j.fuproc.2016.08.003

Research article

Author 

• Yawei Chen
• Weiyu Cao
• Arvind Atreya ^,

• Department of Mechanical Engineering, The University of Michigan, Ann Arbor, MI 48109, USA

Received 20 May 2016. Revised 1 August 2016. Accepted 2 August 2016. Available online 9 August 2016.

Highlights

• Effect of torrefaction on pyrolysis of centimeter-scale pine wood particles was studied.
• •
  For centimeter-scale particles, conversion time was barely affected by torrefaction.
• •
  Temperature and mass loss profiles during pyrolysis were measured to analyze the effects of torrefaction.
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  Bio-oil shows decrease of acid and guaiacol contents and increase of phenol content as torrefaction intensity increases.

Abstract 

The aim of this study is to investigate the effect of torrefaction on pyrolysis of centimeter-scale pine wood particles at 520 °C. The experiments were conducted in a vertical tube furnace and the yields and compositions of bio-oil were measured. We found that torrefaction at 225 °C and 250 °C for 15, 25 and 35 min had little effect on the pyrolysis products. However, when wood was torrefied at 275 °C and 300 °C, significant char formation and transformation occurred. During the pyrolysis processes, lower weight loss rate and higher char fraction were observed for wood torrefied at 275 °C and 300 °C, but the center temperature profiles were not affected. Conversion time for pyrolysis was also not affected by the torrefaction conditions. Pyrolysis yields of liquid, gas and char were calculated and found to be affected by the torrefaction conditions. GC/MS analysis of bio-oil obtained from torrefied wood shows that the acid content decreases with increasing torrefaction intensity, implying improvement of bio-oil quality. Further, phenol content increases and guaiacols content decreases with the increase of torrefaction intensity. On the other hand, no novel species were detected and the overall effect of torrefaction was less remarkable than anticipated for the temperatures tested.

Keywords

Torrefaction

Pyrolysis

Centimeter-scale wood particles

Bio-oil

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  Corresponding author.

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