Forest biomass feedstock cost sensitivity to grinding parameters for bio-jet fuel production

Abstract

Forest harvest residuals in the USA Pacific Northwest are a significant and largely underutilized source of renewable feedstock for “green” power. These forest harvest residuals are, however, not a uniform commodity and many choices can be made for source location, which tree parts to include in the harvest, how to comminute, transport, and process at a biofuels mill-site. Each of these many decisions can and should be informed by the overall impact on value chain costs, including all production costs and any impacts on the conversion process. The number of operational choices is large and the optimal solution not obvious. This paper explores the quantification of a number of the most likely significant operational choices in feedstock harvesting and preparation, and quantifies and ranks the main factors which can impact total value to the overall process of converting forest harvest residues to bio-jet fuel. Under the assumptions used here, total grinding costs are the largest cost impact factor, with a $26.12 per oven-dry tonne impact range. Higher bulk density (as long as moisture content is low enough) reduces hauling cost and is the second most powerful cost effect, having an impact range of $11.31 per oven-dry tonne.