(169c) Fast Pyrolysis of Beetle-Killed Lodgepole Pine

Native bark beetles play an important role in the western forest ecosystems; some level of bark beetle-caused tree mortality is desired for a properly functioning ecosystem. In recent years, however, droughts, warmer winters, and aging forests have led to a beetle epidemic, resulting in a high level of tree mortality. As bark beetle-killed trees fall, heavy surface fuel loads are left on the ground. These fuel loads can act as ladders and carry a ground fire into tree crowns, which will increase the potential for high severity wildfires. Thus, beetle-killed trees should be properly disposed of. Unfortunately, beetle-killed trees have a low commercial value for structural applications because of undesirable properties of blue/black discoloration of sapwood, and low moisture content. Moreover, the standard method of disposing woody residues wastes energy and nutrients. A potential way to deal with beetle-killed trees is through fast pyrolysis, which can essentially convert any form of biomass into a high-value product called bio-oil.  Lodgepole pine (Pinus contorta var. latifolia) is one of the most prevalent tree species in the Pacific Northwest. It is also the main target of mountain pine beetles (Dendroctonus ponderosa) out of the other varieties of pine species that coexist in that region, yet it appears that there are no systematic studies on fast pyrolysis of beetle-killed lodgepole pine (BKLP). In this study, four decay stages of BKLP are selected as feedstock, namely i) green uninfected or minimally infected tree, ii) partially green terminally infected tree, iii) standing dead tree with red needles and bark intact and iv) standing dead tree without needles, 2-4 years after death. This talk will present results for characterization of BKLP feedstock  and fast pyrolysis of BKLP samples carried out via a CDS Pyroprobe 5200 interfacing with a GC/MS. Effects of decay stages and process variables (e.g. temperature and heating rate) on bio-oil composition and distribution will be discussed and the mass balance will be calculated. In the future, a laboratory scale ablative pyrolysis unit for fast pyrolysis of BKLP will be designed and constructed. The operating parameters will be optimized to maximize bio-oil yield.