Sunday, April 29, 2007

Thermochemical options for biofuels production

David C. Dayton, Thomas Foust, Calvin Feik, Kimberly Magrini, John Jechura, Stefan Czernik, Steve Deutch, Daniel Carpenter, Raymond Hansen, Richard French, Steven Phillips, Richard Bain, and Andy Aden. National Bioenergy Center, National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, CO 80401

The feedstock resource availability addressed in the “Billion Ton Vision Study” validates the feasibility of achieving the 30x30 Vision being developed to address the Presidential Biofuels Initiative. Thermochemical conversion provides a technology option for improving the economic viability of the developing bioenergy industry by converting biomass resources not amenable to biochemical conversion technologies into liquid transportation fuels. A thermochemical process can more easily convert low-carbohydrate or “non-fermentable” biomass materials such as forest and wood residues to alcohol fuels adding technology robustness for achieving the 30 x 30 goal.

Biomass gasification product gas consists mainly of CO, H2, CO2, H2O, N2, and hydrocarbons. Minor components of the syngas include tars, sulfur and nitrogen oxides, alkali metals, and particulates. These minor components of the syngas potentially threaten the successful application of downstream fuel conversion steps. Comprehensive cleanup and conditioning of the raw biomass gasification product gas is required to produce a “clean” syngas that be can converted into biofuels. A number of high temperature, high pressure processes, commonly referred to as Fischer-Tropsch synthesis have been developed to produce gasoline, diesel, or mixed alcohol fuel.

This presentation highlights thermochemical ethanol production via biomass gasification/mixed alcohol fuel synthesis. Research activities at NREL include gasification fundamentals and process modeling, catalyst development, integrated gas cleanup and conditioning, and mixed alcohol synthesis. Conceptual designs and techno-economic models have been developed for a biomass gasification process with thermochemical ethanol production via mixed alcohols synthesis to determine how overcoming associated technical barriers contribute to reductions in finished ethanol costs.