Characterization of Fast Pyrolysis Products Generated from Several Western USA Woody Species

Abstract

Woody biomass has the potential to be utilized at an alternative fuel source through its pyrolytic conversion. Here, fast pyrolysis bio-oils derived from several western USA woody species are characterized by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) to determine molecular-level composition. The composition and properties (pH, electrical conductivity, and elemental analyses) of the biochar byproduct were also determined. The bio-oils are comprised mainly of Ox species. Oak (Quercus garryana Douglas ex Hook), mixed conifer (Pseudotsuga menziesii Mirb. Franco, Tsuga heterophylla (Raf.) Sarg, Abies concolor (Gord. & Glend.) Lindl. ex Hildebr.), and scotch broom (Cytisus scoparius (L.) Link) bio-oils contain lower Ox (O1–O7) species that exhibit bimodal distributions whereas mixed conifer feedstock from a fire salvage harvest contains a larger range of Ox species (O2–O13) that exhibit a mainly monomodal distribution. Boron-containing species in the pyrolysis oils were also identified for the first time by FT-ICR MS. Biochar analysis revealed that all biochars had similar pH values (∼7–8); however, the electrical conductivity and elemental analyses varied across the samples. Understanding the composition of pyrolysis byproducts will help direct their uses to the most appropriate locations.