Effects of Torrefaction Severity on the Product Distribution of Two-Stage Pyrolysis

Pyrolysis oil has potential to provide a renewable source of liquid fuel, transportation fuel, or can act as a feedstock for production of renewable chemicals.  There are disadvantageous, though, with traditional pyrolysis oil such as acidity, water content, product inhomogeneity, product quality, and storage stability.  Experimental work has indicated that these problems can be addressed with the use torrefaction as a pretreatment stage to pyrolysis.  This poster will present changes in product distribution between pyrolysis oil generated from raw biomass or from biomass that is torrefied at different severities (time, temperature).  Observed changes include decreased organic acids (>40% reduction), chemically formed water (>60% reduction), the number and quantity of oxygenated compounds (much cleaner GC chromatogram), and relative increased in desired high elemental C/O compounds.   These changes can directly address the issue with traditional pyrolysis oil stated above.  The work is being conducted with a CDS Analytical 5200HP Pyroprobe (250-320C torrefaction, 0-90min; 500C pyrolysis, 20sec).  The product distribution is obtained with a ThermoFisher Trace GC Ultra connected to a DSQII mass spectrometer.  Aspen wood samples sizes studied are between 500-600µm, and 0.05-0.2mg.