(587ah) Enhanced Pyrolysis Oil Properties Through Pretreatment of Aspen With Controlled Torrefaction

Authors: 
Klemetsrud, B., University of North Dakota
Klinger, J., Michigan Technological University
Shonnard, D. R., Michigan Technological University
Bar-Ziv, E., Michigan Technological University



Pyrolysis oil produced from thermochemical conversion of woody biomass has great potential as renewable fuels and feedstocks in chemical production.  Perhaps one of the most exciting ways to utilize biomass resources is in the production of transportation fuels through fast pyrolysis and catalytic upgrading.  Pyrolysis oil, however, has several disadvantages such as high oxygen content, acidity, corrosivity, low storage stability, and high water content.  Our results indicate that these problems can be, at least partially, addressed through the use of torrefaction as a pretreatment method.    During torrefaction, mainly the hemicelluloses fraction of biomass degrades resulting in a more uniform and desirable feedstock for pyrolysis.  This poster presents preliminary data demonstrating that through careful control of torrefaction conditions, the oils formed during a subsequent fast pyrolysis step of aspen have significantly improved acidity (>60% reduction), corrosivity, water content(>25% removal), oxygen content(chromatographic shift), and thus improved storage stability and energy content.  Pyrolysis (500°C for 15 seconds) and torrefaction (300°C for between 5 to 90 minutes) experiments were carried out in a high purity helium atmosphere on a 5200HP Pyroprobe (CDS Analytical), and the chemical analysis performed with a Trace GC coupled with a DSQII mass spectrometer (both Thermo-Fisher Scientific).  Wood (aspen) sample sizes were on the order of 500µm and 1.0mg.