Lignocellulosic Biorefineries: Reality, Hype, or Something in Between?

Abstract

With growing concerns over increasing fuel prices, green house gas emissions and the national security issues surrounding reliance on imported oil, there is an increasing interest in technologies that allow for sustainable production of energy and fuels from domestic resources. Among the various renewable energy options, lignocellulosic biomass is unique in its ability to produce liquid transportation fuels, which can be integrated into the current fuel infrastructure. There are a wide variety of technologies that can be used to convert lignocellulosic biomass into liquid fuels, including fermentation of sugars and production of liquid fuels from biomass derived syngas. There are also two industries with well-developed biomass conversion infrastructure, the corn ethanol industry, and the pulp and paper industry, that could be used as a launch point for developing lignocellulosic biorefineries. These industries offer opportunities for 1) producing monomeric sugars from biomass residues that can be fermented into ethanol, and 2) additional opportunities for converting the lignin-rich fermentation residues and low quality biomass residues to syngas that can be used to produce liquid fuels. The pulp and paper industry offers opportunities for 3) extracting fermentable sugars prior to pulping and converting these sugars to ethanol, and 4) gasifying the biomass or lignin-rich spent pulping liquors for the production of liquid fuels. Finally, there are attractive technologies being developed for the direct conversion of biomass-derived oils into transportation fuels in petroleum refineries. In all of these technology areas there have been significant advances, but there is still a need for additional technology development to overcome economic challenges. There is also a need for a better understanding of the energy and environmental benefits of these lignocellulosic biorefineries. This paper will highlight the technical challenges to be overcome, and potential for producing fuel products from lignocellulosic biomass.