The consequences of extracting com stover feedstock with either 95% ethanol or hot water prior to the chemical analysis of the macrocomponents of that feedstock have been determined. Reports by others have recommended the removal of extraneous substance by solvent extraction prior to chemical analyses (Browning, 1967; TAPPI, 1988). The 95% ethanol extraction evaluated in this study is currently the "standard" method recommended by the National Renewable Energy Laboratory, Golden, Co. Hot water extractions were tested as a simple, less time consuming and less expensive alternative to ethanol extractions. Compositional analyses involved the quantification of glycans, Klason lignin, acid soluble lignin, ash, protein, acetic acid, and uronic acids. The summative analysis of native, ethanol extracted and water extracted feedstocks were all in the range of 97 to 98%. Ethanol extractions removed 4.9% of the feedstock dry weight, compared to 17.2% of the dry matter being extracted with hot water. The extractives obtained via ethanol had negligible amounts of glycans. In contrast, the water extracted solids contained nearly 10% of the native feedstock total glucan. Pre-extracting the feedstock with ethanol had little effect, relative to the native feedstock, on the quantification of glycan components. In contrast, the water extracted feedstock measured significantly lower in total glucans and total glycans than the native feedstock. The lower values associated with the water extraction were due to the actual extraction of glucans from the feedstock, and not due to analytical interferences associated with the extractives. Ethanol and water extracted feedstocks measured significantly lower in Klason lignin than the corresponding native feedstock. This was presumably due to the removal of Klason lignin impurities present in the native feedstock, and not due to the extraction of lignin itself. The combined results from this study indicate that an informative approach to the analysis of com stover feedstock would include the pre-extraction of the feedstock with hot water prior to further analyses. The appropriate macrocomponent analyses should then be done on both the extracted feedstock and the "extractives" obtained from that feedstock. Analysis of the extracted feedstock, as compared to the native feedstock, would provide more accurate estimates of the cellulose and lignin content of the feedstock. The summative analysis of both the extracted solids and the extractives will provide a reliable estimate of the total amount of carbohydrate potentially available in the feedstock for microbial fermentation to ethanol. / Graduation date: 1996

Dissertation (Ph.D.) -- Auburn University, 2005. / Vita. Includes bibliographical references (ℓ. 117-132).

The renewable energy industry continues to expand at a rapid pace. New advances in cellulosic ethanol technologies have the potential to reduce our dependency on foreign oil. The evolution of these new biofuel markets could have significant effects on future production levels, market prices, and world trade levels for various agricultural commodities. Alternative scenarios involving new biofuel technologies, primary factor availability, and government policy will result in very different outcomes for the agricultural economy. The interactions of current and new biofuel technologies, including conventional ethanol production (from corn grain) and cellulosic ethanol production (from corn stover and switchgrass), and the agricultural economy were examined in a general equilibrium framework. Various outcomes were examined with attention primarily focused on (1) trade offs among competing uses of agricultural commodities, (2) changes in the output of major agricultural producers competing with the U.S., (3) effects on the livestock industry, (4) profitability of the agricultural industry, (5) changes in input costs, including land rents, and (6) changes in land use patterns. Results indicated that advances in cellulosic ethanol technology led to less grain ethanol production and more stover ethanol production in the United States. The production of switchgrass ethanol was not economically feasible under any scenario, which was expected due to the availability of lower priced corn stover. Overall, it was expected that a decrease in the costs of cellulosic ethanol production would lead to a higher increase in total U.S. ethanol production than actually occurred. As a result, the effects on the world economy were smaller than expected.

Thesis(M.S.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on December 30, 2009). Thesis advisor: Dr. Jinglu Tan. Includes bibliographical references.

Due to security issues in energy supply and environmental concerns, renewable energy production from biomass becomes an increasingly important area of study. Thus, thermal conversion of biomass via pyrolysis and subsequent upgrading procedures were explored, in an attempt to convert an abundant agricultural residue, corn stover, into potential bio-fuels. Pyrolysis of corn stover was carried out at 400, 500 and 600oC and at moderate pressure. Maximum bio-char yield of 37.3 wt.% and liquid product yield of 31.4 wt.% were obtained at 400oC while the gas yield was maximum at 600oC (21.2 wt.%). Bio-char characteristics (energy content, proximate and ultimate analyses) indicated its potential as alternative solid fuel. The bio-oil mainly consisted of phenolic compounds, with significant proportions of aromatic and aliphatic compounds. The gas product has energy content ranging from 10.1 to 21.7 MJ m-3, attributed to significant quantities of methane, hydrogen and carbon dioxide. Mass and energy conversion efficiencies indicated that majority of the mass and energy contained in the feedstock was transferred to the bio-char. Fractional distillation of the bio-oil at atmospheric and reduced pressure yielded approximately 40-45 wt.% heavy distillate (180-250oC) with significantly reduced moisture and total acid number (TAN) and greater energy content. Aromatic compounds and oxygenated compounds were distributed in the light and middle fractions while phenolic compounds were concentrated in the heavy fraction. Finally, hydrotreatment of the bio-oil and the heavy distillate using noble metal catalysts such as ruthenium and palladium on carbon support at 100 bar pressure, 4 hours reaction time and 200o or 300oC showed that ruthenium performed better at the higher temperature (300oC) and was more effective than palladium, giving about 25-26% deoxygenation. The hydrotreated product from the heavy distillate with ruthenium as catalyst at 300oC had the lowest oxygen content and exhibited better product properties (lower moisture, TAN, and highest heating value), and can be a potential feedstock for co-processing with crude oils in existing refineries. Major reactions involved were conversion of phenolics to aromatics and hydrogenation of ketones to alcohols. Results showed that pyrolysis of corn stover and product upgrading produced potentially valuable sources of fuel and chemical feedstock.

Thesis (Ph.D.)--University of Minnesota, 2007. / Advisers: Roger Ruan, Jun Zhu. Includes bibliographical references.

Thesis (Ph. D.)--Auburn University, 2008. / Vita. Includes bibliographical references (p. 223-241).

Dissertation (Ph.D.)--Auburn University, 2004. / Abstract. Vita. Includes bibliographic references (p.163-173).