(625d) Techno-Economic Analysis of Biofuels from High Moisture Feedstock Via Hydrothermal Liquefaction and Anaerobic Digestion

Techno-economic analysis of biofuels from high moisture
feedstock via hydrothermal liquefaction and anaerobic digestion

Mitch Amundson, Mark Mba Wright

The purpose of this study is to develop an economic model
that analyzes biofuel production from high moisture feedstocks. In this
preliminary study, corn silage, sweet sorghum and giant miscanthus are used as
feedstocks and converted by means of hydrothermal liquefaction (HTL) and
hydroprocessing or anaerobic digestion (AD) and Fischer Tropsch (FT) upgrading
or methanol to gasoline (MtG) upgrading. Results yield a comparative economic
analysis of mass and energy balances for each scenario.

The US
Department of Energy determined that economic biofuel production advises that
the logistics cost do not exceed 19% of the final ethanol production price
($/gge). Logistics cost include: harvesting, baling/storage, handling,
transportation and preprocessing. For most thermochemical conversion pathways a
dry feedstock (<10wt% moisture) is essential to obtain reasonable
efficiencies. Feedstock drying is an energy intensive and expensive process so
conversion methods where moisture content is not a factor may hold the answer
to reducing biofuel prices.

This
comparison study analyzes the economic viability of various plant sizes,
feedstocks, harvesting and storage methods, conversion processes and upgrading
technologies. The model shows that for most scenarios the logistic cost is less
than the target 19% of total fuel price and fuel prices are within a reasonable
range. After preliminary studies, results show potential promise in high moisture
feedstock biofuel production.