KREC: Development of an Ethanol Pilot Scale Facility to Evaluate the Effect of Collection, Storage, and Pretreatment of Corn Stover

Biomass conversion to liquid products has the potential to reduce domestic dependence on imported petroleum crude used for the production of fuels and industrial chemicals. The realignment of the US chemical industry from petrochemical refining to a bio-refinery system was made a national goal by President Clinton in Executive Order 13134 (1999), subsequently followed by clearly defined goals for increasing the use of biomass derived feedstocks in industrial chemical production. In August of this year, the Energy Policy Act of2005 was signed into law, which includes a significant emphasis on renewable energy efforts. Kentucky's abundance of natural resources, including forestry wastes and agricultural residues, offers a vast resource of available and underutilized biomass. Biochemicals and biofuels can be produced from agricultural residues by microbial fermentation after the cellulose and hemicellulose are converted to fermentable sugars. The collection, storage, pretreatment, hydrolysis, and fermentation of biomass feedstocks significantly affect the economics of the final products including fuel ethanol. The DOE has identified com stover as a key feedstock for production of fermentable sugars. The overall objective of this research is to increase the value of com stover as a sugar feedstock by separating the plant fractions that are most economical and efficient to collect, store, pretreat, saccharify, and ferment to value added products. Stover fractions that have been shown to be more susceptible to pretreatment (i.e. leaves, husks, and cobs) will be collected in a single pass operation. The second step involves storage of the stover fractions as silage to eliminate the need for drying. A laboratory, pilot-scale facility will be developed to aid in the evaluation of overall system performance, i.e. converting com stover to ethanol. Ensiling effects on downstream processing (pretreatment required and enzymatic hydrolysis) will be evaluated. After hydrolysis, Saccharomyces cerevisiae will be used to ferment the glucose into ethanol and will be the metric for calculating overall system performance. The resulting data will be used to evaluate the potential for ensiling com stover, performing pretreatment, and enzymatic on-farm conversion to fermentable sugars. Conversion of the material to ethanol will verify that the material resulted in a higher value biomass feedstock and will be compared to field dried whole plant com stover, DOE's preferred sugar platform feedstock. This proposal supports the goals and objectives identified in the DOE Multi-Year Technical plan related to feedstock collection and the sugar platform, and recommendations made in the KY Comprehensive Energy plan (specifically recommendations 10,48,50, and 51).