At present, the world's transportation sector is being principally supplied by fossil fuels. However, energy consumption in this sector is drastically increasing and there are concerns with supply, cost, and environmental issues with the continuing use of fossil fuels. Utilizing non-petroleum ethanol in the transportation sector reduces the dependence on oil, and allows for cleaner burning of gasoline. Lignocellulose materials are structurally composed of five types of polymeric sugars, glucan, galactan, mannan, arabinan, and xylan. NREL has developed a quantitative saccharification (QS) method for determining carbohydrate composition. We proposed a new protocol based on the NREL 2006 Laboratory Analytical Procedure "Determination of Structural Carbohydrates and Lignin in Biomass" (Sluiter et al. 2006a) with a slight modification, in which xylose concentration was determined after the secondary hydrolysis by using 1% sulfuric acid rather than 4% sulfuric acid. We found that the current NREL protocol led to a statistically significant overestimation of acid-labile xylan content ranging from 4 to 8 percent. Lignocellulosic biomass is naturally recalcitrant to enzymatic hydrolysis, and must be pretreated before it can be effectively used for bioethanol production. One such pretreatment is a fractionation process that separates lignin and hemicellulose from the cellulose and converts crystalline cellulose microfibrils to amorphous cellulose. Here we evaluated the feasibility of lignocellulose fractionation applicable to the hurds of industrial hemp. Hurds are the remaining material of the stalk after all leaves, seeds, and fiber have been stripped from the plant. After optimizing acid concentration, reaction time and temperature, the pretreated cellulosic samples were hydrolyzed to more than 96% after 24 hours of hydrolysis (enzyme loading conditions of 15 FPU/g glucan Spezyme CP and 60 IU/g glucan Novozyme 188) at the optimal pretreatment condition (> 84% H₃PO₄, > 50 °C and > 1 hour). The overall glucose and xylose yields were 89% (94% pretreatment; 96% digestibility) and 61%, respectively. All data suggest the technical feasibility of building a biorefinery based on the hurds of industrial hemp as a feedstock and a new lignocellulose fractionation technology for producing cellulosic ethanol. The choice of feedstock and processing technology gives high sugar yields, low processing costs, low cost feedstock, and low capital investment. / Master of Science

The objective of this thesis was to further develop the polymer composite system consisting of cellulose acetate butyrate (CAB) and high modulus, continuous, regenerated cellulose fiber (lyocell). Of particular concern were both the interfacial adhesion between the fiber and matrix and the consolidation process in the manufacture of these composite materials. Interfacial adhesion was found to be substantial due to the relative lack of the fiber pull-out phenomenon observed after tensile failure in the unmodified fiber composites. This result was then supported in the second study in which similar unmodified fiber composites experienced very little fiber pull out with evidence of a large amount of cohesive failure of the matrix accompanied by matrix particles adhering to the fiber surfaces. Void volume formation was mitigated to a small extent by the use of optimal consolidation conditions. Composites formed at moderate temperature (200 °C), low consolidation pressure (11.8 p.s.i.) and high consolidation time (13 min.) were found to have the lowest void volume formation of ca. 2.8 %. These composites were generally found to have the highest interfacial shear strength, ca. 16 MPa. A tensile modulus of 22 GPa and an ultimate strength of 246 MPa was obtained for this composite having a fiber volume content of ca. 62 %. / Master of Science

La présente étude vise à valoriser des résidus agroindustriels comme matériaux pour l’habitat et la construction. Dans ce contexte, les travaux de recherche s’articulent autour de deux axes majeurs : le développement d’un liant alternatif et l’élaboration de matériaux composites à partir de ce liant alternatif et des matériaux végétaux. Deux liants composés utilisant des cendres de bagasse, nommés cendres de bagasse-chaux et ciment-cendres de bagasse ont été étudiés. A partir de ces liants composés, deux types de matériaux composites incluant des matériaux végétaux ont été élaborés : un composite incorporant des granulats de bagasse et de coco et un autre renforcé par des pulpes d’eucalyptus. Les propriétés physiques, chimiques, mécaniques et hydriques de ces matériaux ont été déterminées. Les résultats obtenus montrent que la calcination des cendres de bagasse à 600°C et la sélection des particules de taille inférieure à un diamètre seuil compris entre 45 et 63µm augmentent sa réactivité. Le liant composé cendres de bagasse-chaux est susceptible de développer une résistance à la compression de l’ordre de 39MPa à 28 jours, une valeur supérieure à celle des liants composés matériaux pouzzolaniques-chaux étudiés dans la littérature. Grace à sa faible alcalinité, ce liant composé préserve mieux les matériaux végétaux vis à vis de leur minéralisation et leur fragilisation comparativement au liant à base de ciment. L’incorporation de pulpes cellulosiques dans le liant composé cendres de bagasse-chaux permet d’obtenir des matériaux composites ayant des propriétés à la flexion comparables à celles d’un composite ciment-pulpes cellulosiques. / The present study aims to add value to agroindustrial residues as housing and building materials. In this context, the research works revolve around two main lines: the development of an alternative binder using agroindustrial residues and the production of composite materials from this alternative binder and plant resources. Two composed binder using bagasse ash, named bagasse ash lime and cement-bagasse ash, were optimised and produced. Using these composed binder, two kinds of composite materials including plant resources were produced: one composite developed with vegetable aggregates and another one reinforced with eucalyptus pulps. The physical, chemical, mechanical and hydric properties of these materials were investigated. The results show that the bagasse ash recalcination at 600 °C and the selection of the particles under a diameter limit (between 45 and 63 µm) improve its reactivity. Blended with slaked lime, the composed binder obtained with these parameters is likely to develop a compressive strength higher than 39 MPa at 28 days; this value is higher than the compressive strength of pouzzolanic material and lime based binder studied in the literature. In addition, due to the lower alkalinity of the interstitial solution of this composed binder, related to the lime consumption by the pouzzolanic material, it better protects vegetable materials from mineralization than the binders based on Portland cement. The incorporation of the cellulosic pulps in the composed binder lime-bagasse ash produces composite materials with a similar flexural behaviour as a composite made with cement and cellulosic pulp.

Motivation - Neue Anwendungen für cellulosische Fasern z.B. in 3D-Verpackungslösungen, im Leichtbau oder in Konstruktionswerkstoffen - Technologisch effiziente Herstellbarkeit wird gefordert (z.B. integriertes Umformen und Fügen) - Verfügbarkeit geeigneter Simulationswerkzeuge unabdingbar (z.B. mittels FE-Analyse)

Doctor of Philosophy / Department of Agricultural Economics / Jason S. Bergtold / The adoption of new technologies on-farm is affected by socio-economic, risk management behavior, and market factors. The adoption of cellulosic biofuel feedstock enterprises and conservation practices plays an important role in the future of Kansas agriculture. No set markets currently exist for bioenergy feedstocks and farmers may be reluctant to produce the feedstocks without contracts to mitigate uncertainty and risk. Adoption of conservation practices to improve soil productivity and health may be affected by risk considerations also. The purpose of this dissertation is to study how market mechanisms and risk influence Kansas farmers’ willingness to adopt cellulosic biofuel feedstock enterprises and conservation practices on-farm. The first essay examines farmers’ willingness to grow switchgrass under contract using a stated choice approach. Data were collected using an enumerated survey of Kansas farmers and analyzed using latent class logistic regression models. Farmers whose primary enterprise is livestock are less inclined to grow switchgrass. In addition, shorter contracts, greater harvest flexibility, crop insurance, and cost-share assistance increase the likelihood farmers will grow switchgrass. The second essay examines how farmers’ risk perceptions impact conservation practice adoption. Factor analysis of survey data was used to identify primary risk management behaviors of Kansas farmers. A multinomial logit model of conservation practice adoption incorporating these risk behaviors was developed. Estimation results indicate that different risk management factors may have no significant impact on practice adoption. Farmers may not consider certain aspects of risk significant in their adoption decision. The third essay examines the effect of different risk management behaviors on farmers’ willingness to produce alternative cellulosic bioenergy feedstocks under contract. Data were collected using a farmer survey with a set of stated choice experiments and analyzed using factor analysis and latent class logistic regression models. While farmers approach risk management differently, the risk management behaviors identified have no significant impact on farmers’ willingness to produce corn stover and switchgrass but have a negative impact on farmers’ willingness to produce sweet sorghum as a biofuel feedstock. These results may indicate that farmers are indifferent toward adopting new bioenergy cropping enterprises when traditional crop production is profitable and more certain.

Master of Science / Department of Agricultural Economics / Jeffery Williams / Ethanol has become an important source of energy for transportation purposes in the U.S. The majority of the feedstock for this ethanol is corn grain. The use of crop residues and perennial grasses has been proposed as an alternative feedstock for ethanol production using cellulosic conversion processes. Commercial scale production of cellulosic ethanol is still on the horizon. In the meantime a wide variety of studies examining both the technical and economic feasibility of cellulosic ethanol production have been conducted. This is the first study that combines both county level cellulosic feedstock production and farmer participation rates to determine the feasibility of supplying it to cellulosic ethanol plants. This research determines the economic feasibility of supplying cellulosic feedstocks to seven potential add-on cellulosic ethanol plants of 25 million gallons per year at seven existing starch ethanol plants in Kansas. The feedstocks considered are corn stover, sorghum stalks, wheat straw, and perennial switchgrass. A mixed integer programing model determines the amount and mix of cellulosic feedstocks that can be delivered to these plants over a range of plant-gate feedstock prices given transportation costs and farm-gate production costs or breakeven prices. The variable costs of shipping are subtracted from the difference between plant-gate price and farm-gate price to find savings to the plant. The objective function of the model minimizes transportation costs which in turn maximizes savings to the plant. The role switchgrass may have as a feedstock given various switchgrass production subsidies is examined. The results indicate the minimum plant-gate price that must be paid to feedstock producers for all plants to have enough cellulosic feedstocks is $75 per dry ton. Switchgrass feedstocks were only a minor portion of biomass supplied and used without a production subsidy. A Biomass Crop Assistance Program payment increased the supply of switchgrass more than other production subsidies.

Master of Science / Department of Grain Science and Industry / Leland McKinney / The current forage handling equipment in the cellulosic ethanol industry is severely limited by the low bulk densities of baled and ground biomass. Low bulk densities contribute to flowability problems and lack of maximizing trailer capacities. By pelleting we can increase the bulk density and flowability characteristics of forages. The objectives of this research were to evaluate (1) the energy requirements of grinding sorghum stalks, corn stover, wheat straw and big bluestem through two different screen sizes, (2) the energy requirements of pelleting forages from the two grind sizes, and (3) the physical properties of our various end products. The two screen types were found to have significantly different energy consumptions from each other (P<.0001). The majority of the four forage types were also found to have significantly different energy consumptions for grinding from each other (P<.0001). The exception was big bluestem vs. corn (P=.2329). All of the 1/8” vs. 1/8” and 1/8” vs. 3/8” grinds were significantly different from each other (Most P<.0001 and all at least P<.05). 3/8” sorghum was significant against all other 3/8” forage types. No other comparisons were significant for 3/8” vs. 3/8” (All 3/8” sorghum P<.0001). Production rate through the 3/8” screen was almost 3 times that of the 1/8” screen (Average of 400 lb/hr vs. 150 lb/hr). The two screen types were found to have significantly different energy consumptions for pelleting from each other (P<.0001). The four forage types were also found to have significantly different energy consumptions from each other (P<.0001) while the big blue vs. wheat did not. (P=.1192). Particle length for the 1/8” grind ranged from .06 inches to .07 inches, while the 3/8” grind ranged from .08 inches to .12 inches. Pelleting increased bulk density from 6.24 lb/ft3 to 9.99 lb/ft3 for biomass grinds to 31.17 lb/ft3 to 43.77 lb/ft3 for pelleted biomass. Pellet quality ranged from 93% to 98%. A cost analysis indicated that it would take roughly $20 extra per ton for the transportation, pre-processing and storage of pelleted cellulosic biomass than whole corn. This cost is still almost half that of the cost for baled biomass.

Master of Agribusiness / Department of Agricultural Economics / Michael Woolverton / To meet the demand of the 2007 Energy Bill will require a new approach to ethanol production in the United States. The question persists: how can the ethanol industry in the United States produce 21 billion gallons of ethanol from cellulosic sources? This challenge will require changes in the facilities currently manufacturing ethanol, the collection and storage methods to which the Midwestern farmer is accustomed, and a drastic change in farm production practices. Several different methods of cellulosic ethanol production are being examined. One such method is to change the focus from starch based ethanol to ethanol produced by harvest, collection, and manufacture from corn cobs. Research has included surveys, development of economic models, and focus group meetings to determine the feasibility of corn cobs as a viable raw material source for cellulosic ethanol. Findings indicate that: corn cob collection is feasible for the Midwestern farmer. According to the economic models presented in this thesis, Midwestern farmers can benefit economically from the collection of corn cobs. Further, the collection of corn cobs allows for current ethanol plants to be upgraded with new technology without major change in the manufacturing processes. The focus of this research was to determine which method of corn cob collection was preferable for Midwestern corn producers.

A carbonatação acelerada é um processo químico que têm se tornado muito atrativa para a indústria do fibrocimento, por mitigar a degradação das fibras vegetais utilizadas nos materiais e por melhorar o desempenho físico-mecânico dos compósitos. Nesse contexto, o presente trabalho avaliou a influência da umidade no processo de carbonatação acelerada, em fibrocimentos reforçados com polpas celulósicas de eucalipto. Para o desenvolvimento das atividades experimentais foi realizado primeiramente um estudo da evolução da carbonatação nos compósitos de fibrocimento, considerando diferentes concentrações de umidade relativa (60, 70, 80 e 90%). Posteriormente, foi realizada a caracterização dos compósitos de fibrocimento por meio da avaliação do desempenho físico-mecânico, com ensaio mecânico de flexão em quatro pontos que determinou o módulo de ruptura (MOR), módulo elástico (MOE), limite de proporcionalidade (LOP) e energia específica (EE); e ensaios físicos para obtenção dos valores de absorção de água (AA), densidade aparente (DA) e porosidade aparente (PA). Os compósitos foram também avaliados quanto à durabilidade e microestrutura, através de ensaios de envelhecimento acelerado, composição mineralógica e análise microestrutural. A partir dos resultados obtidos, os compósitos carbonatados com 60% de umidade relativa apresentaram maior formação de carbonato de cálcio, maior densificação da matriz cimentícia e, consequentemente, menor quantidade de espaços vazios logo nas primeiras horas de carbonatação. Em relação ao desempenho dos compósitos de fibrocimento, as umidades de 60 e 70% permitiram que a carbonatação proporcionasse maiores valores de MOR, LOP e MOE, diferindo estatisticamente dos demais compósitos. Os ensaios físicos complementaram os ensaios mecânicos, mostrando que os compósitos carbonatados com 60 e 70% de umidade apresentaram menores valores de AA e PA, junto de maiores valores de DA. O processo de carbonatação acelerada foi favorecido pelas menores concentrações de umidade relativa, como apresentado também pelas análises de TG e DRX, que permitiram que o processo acontecesse de forma mais efetiva, melhorando a interface fibra-matriz. / The accelerated carbonation is a process that can be made very feasible for the fiber cement industry, for mitigating the degradation of the vegetable fibers used in the materials and for improving the physico-mechanical performance of composites. In this context, the present work evaluated the influence of relative humidity in the accelerated carbonation process in fiber cement composites reinforced with eucalyptus cellulosic pulps. For the development of experimental activities, a study of the evolution of carbonation in fiber cement composites was carried out, considering different concentrations of relative humidity (60, 70, 80 e 90%). Subsequently, the characterization of fiber cement composites was evaluated through the physical-mechanical performance evaluation, with a four-point mechanical test that determined the modulus of rupture, modulus of elasticity, limit of proportionality and specific energy; and physical tests to obtain the values of water absorption, bulk density and apparent void volume. The composites were also evaluated for durability and microstructure, through accelerated aging, mineralogical composition and microstructural analysis. From the results obtained, the carbonate composites with 60% relative humidity showed a higher calcium carbonate formation, a higher densification of the cementitious matrix and, consequently, a lower amount of voids in the first few hours of carbonation. In relation of the performance of fiber cement composites, the 60 and 70% humidity allowed the carbonation to provide higher values of mechanical analysis, differing statistically from the other composites. The physical tests complemented the mechanical tests, showing that the carbonated composites with 60 and 70% humidity presented lower values of water absorption and apparent void volume, with a greater filling of the empty spaces of the composites. The accelerated carbonation process was favored by the lower concentrations of relative humidity, as also shown by the TG and XRD analyzes, which allowed the process to happen more effectively, improving the fiber-matrix interface.

Este trabalho visa a valorização da fração de xilana presente na polpa kraft branqueada de eucalipto como matéria prima para a produção de xilitol e derivados de xilose. O presente estudo é dividido em dois objetivos principais. A primeira parte é dedicada ao estudo da otimização do processo de extração da xilana da polpa kraft industrial. Para fazer este estudo foi estabelecido um planejamento fatorial utilizando como variáveis a concentração da solução de hidróxido de sódio, o tempo de extração e a razão sólido/líquido (polpa/solução). A resposta empregada para avaliar a eficiência das extrações foi o rendimento de xilana extraída. A melhor condição de extração foi obtida com solução de hidróxido de sódio 14% (m/v), 180 minutos e razão sólido/líquido de 0,06, resultando em 98% de xilana extraída. Na segunda parte, estudou-se o processo de recuperação da xilana a partir das soluções de extração por técnicas de precipitação utilizando ácidos e/ou álcoois. Devido à presença de impurezas no precipitado, estudou-se também o efeito da lavagem dos mesmos. A partir da caracterização das amostras isoladas pode-se concluir que as xilanas isoladas utilizando metanol, isopropanol, ácido clorídrico e ácido nítrico apresentaram graus de pureza comparáveis à de amostras comerciais de xilana. / This work aims the extraction of xylans present in bleached eucalyptus kraft pulp. The extracted xylans can be used as raw material for the production of xylitol and xylose derivatives. The study is divided in two main objectives: The first part is dedicated to optimize the conditions to extract xylan from industrial Kraft pulps. To achieve this, a factorial planning design was established using as variables the concentration of sodium hydroxide solution, extraction time and the solid (pulp) to solution ratio. The response to employed to evaluate the extraction efficiency was the recovery xylan yield. The best extraction condition was obtained with 14% (w/v) sodium hydroxide, 180 minutes and solid (pulp) to liquid ratio of 0.06, which lead to approximately 98% of xylan recovery yields. In the second part of this work, the recovery of the pure xylan from the aqueous solution was carried out by precipitation techniques using acids and / or alcohols. Due to the presence of impurities in the precipitates, it was also studied the effect of washing to purify the samples. From the characterization of the isolated samples it can be concluded that xylans precipitated by using methanol, isopropanol, hydrochloric acid and nitric acid, produced xylans samples with similar level of purity when compared to the commercial standard xylan.