2013 Project List

Ethanol production from Xylose (Dr. Jin Wang)

Lignocellulosic ethanol has been identified as one of the most promising long-term renewable energy sources, not only because lignocellulosic biomass is the most abundant and inexpensive renewable feedstock for ethanol production, but also because cellulosic ethanol can reduce both energy input and greenhouse gas emissions by more than 85% compared to fossil fuels and corn ethanol. Although ethanolic fermentation of glucose derived from cellulosic biomass, using Saccharomyces cerevisiae, is well established on a large scale, the conversion of the xylose, one major sugar component of hemicelluloses, to ethanol is still one of the major barriers of industrializing lignocellulosic ethanol processes. Pichia stipitis has been shown to be the most promising wild strain for direct high-yield fermentation of xylose without byproduct formation, and it has been a source of genes for engineering xylose metabolism in S. cerevisiae. It has been reported that the ethanol production rate of P. stipitis is quite sensitive to the availability of oxygen during fermentation. However, there is a lack of quantitative study of this aspect. In addition, there are different strains of P. stipitis, and the literature has reported quite different performances of ethanol production of different strains. In this project, the REU student will compare two most commonly used P. stipitis strains in term of fermenting xylose into ethanol, and study their sensitivity to the oxygen transfer rate.

Deoxygenation of Bio-oil for Hydrocarbons (Dr. Sushil Adhikari)

The conversion of biomass to pyrolysis oil (bio-oil) and subsequent conversion to gasoline and diesel range compounds have significant potential for reducing the United States’ dependence on current petroleum imports. However, this oil is unstable and acidic, contains char particles, and has about half the heating value of petroleum liquid fuels. These properties of bio-oil have restricted its use in commercial applications. The upgrading of bio-oil to hydrocarbons can be done through hydrodeoxygenation, but this process requires an external supply of hydrogen. The objective of this research is to produce hydrogen in-situ, and utilize hydrogen for deoxygenation of bio-oil in a single reactor. The main hypothesis of this study is that C1-C4 compounds can be reformed to produce hydrogen in a single reactor while deoxygenating higher carbon containing molecules. The REU student will test the effectiveness of selected heterogeneous catalysts to reform and deoxygenate bio-oil at different temperatures and pressures in a single reactor.

High-value Co-product Development from Hemicellulose (Dr. Maobing Tu)

The development of high-value co-products, such as oxygen barrier films, from hemicellulose will generate extra revenue for the bioconversion process, and becomes critical to the economic viability of biofuels production. There is a growing interest in developing polysaccharides derived films with low oxygen permeability for food packaging applications. The biobased oxygen barrier films can potentially increase the quality and shelf life of packaged food products. The central hypothesis is that the material properties of oxygen barrier films depend on the chemical structure of hemicellulose, which in turn depends on biomass resources and extraction methods. The specific objective here is to determine the correlation between hemicellulose structure and material properties of oxygen barrier films. The REU students will separate isolated hemicelluloses into different fractions based on their molecular weights using membrane ultrafiltration, and those fractions will be characterized by an HPLC and a GC/MS for their side chain (o-acetyl groups and uronic acid groups). The fractions will be cast into barrier films, and the properties of these films will be correlated with the hemicellulose structure.

Synthesis of Novel Epoxy Nano-composites (Dr. Maria Auad)

Bio-oil can be useful for synthesis of value added epoxy resins. Epoxy resins are traditionally petroleum based materials that offer excellent mechanical and electrical insulation properties, adhesion to a variety of materials, and chemical resistance. These thermosetting resins are utilized in fiber-reinforced plastic materials, coatings, adhesives, insulation, and structural applications. Bio-based polymer resins (i.e. biobased epoxy resins) from agricultural and woody biomass could reduce the dependence on foreign oil, and lower carbon dioxide emissions. The main hypothesis of this study is that the availability of OH groups in bio-oil is important for optimal epoxy synthesis. The objective of this project is to prepare a biobased epoxy resin that is comparable in mechanical properties to conventional epoxy resin. The REU student will prepare biobased expoxy by reacting a commercial epoxy resin (Epon 828 equivalent weight: 178 g/equiv) with bio-oil at different concentrations. The student will learn to operate different epoxy characterizing equipment such as a thermogravimetric analyzer (TGA), a differential scanning calorimeter (DSC), an FITR, and a texture analyzer.

Fuel Combustion Visualization (Dr. Steve Duke)

The goal of the work in our combustion visualization laboratory is to characterize burn and energy conversion phenomena and efficiencies for alternative fuels, particularly focusing on direct comparative combustion studies between alternative fuel particles (or droplets) with their traditional fossil fuel counterparts. Specialized drop tube furnaces are used to determine effects of fuel feed properties, oxygen level, temperature, flow, density, and other process conditions on energy conversion efficiency. A combination of optical high speed and high magnification visualizations and pyrometer-based measurements allow characterization of burn times, instantaneous surface temperature distributions, flame properties, and char formation. Fundamental and applied studies of energy conversion are conducted for biomasses (switch grass, wood wastes, broiler litter), bio-derived liquids, and solid waste fuels (plastics, railroad ties, construction debris). The REU fellow will work with a specific alternative fuel and learn about combustion kinetics, visualization technique development and image processing, and transport processes in combustion and energy conversion environments.

Bio-oil Based Resins (Dr. Brian Via)

An extender is commonly applied with formaldehyde based resins during wood composite production resulting in less usage of the base resin, and thus lower formaldehyde emissions in the final composite product. Resin extenders are commonly monomer sized, and the small molecular weight may help to accelerate the reaction during resin polymer synthesis. During the pyrolysis process, the molecules are broken down to monomer sized phenolic units which may be more reactive with phenol formaldehyde resin. It is hypothesized that bio-oil can be used as an extender for formaldehyde based resins. The objective of this research is to produce oriented strand board (OSB) products with phenol formaldehyde resin that has been extended with bio-oil. The goal will be to determine if the amount of formaldehyde based resin can be reduced while maintaining composite mechanical propertiesThe REU student will prepare OSBs by mixing phenol formaldehyde with different concentrations of bio-oil. Once the OSBs are manufactured, the student will then test the mechanical properties of the composite to ensure that the same mechanical properties are achievable when less formaldehyde based resin is used. During the course of experimentation, the student will be exposed to an array of laboratory equipment such as texture analyzer, TGA and DSC.

Biodiesel Production from Biological Wastewater Treatment Plant (Dr. Ahjeong Son)

Activated sludge, also known as mixed liquor, is part of the conventional treatment of wastewater and it consists of a number of microorganisms. The main components of the microbial cell membrane (phospholipid bilayer) are phosphate, glycerol, and two fatty acids. Microbial fatty acids can be easily modified into fatty acid methyl ester (biodiesel). The objective of the work described here is to develop a sustainable method of producing biodiesel from wastewater sludge in a biological wastewater treamtne plant. The hypothesis is the wasted activated sludge and digested sludge as a microbial consortium will serve an excellent source of biodiesel by providing the raw material in the form of phospholipid bilayer cell membranes. The REU participant will involve in extracting oil from sludge, converting into biodiesel, and performing characterization work.

Enhanced liquefaction of Biomass in Supercritical Water using Inorganic Catalysts (Dr. Ram Gupta)

Water is supercritical at a temperature >374 °C and a pressure >22.1 MPa, where it has liquid-like density and gas-like transport properties, and behaves very differently than it does at ambient conditions. For example, it is highly non-polar at supercritical conditions, thereby permitting complete solubilization of most organic compounds and oxygen. The objective of this project is to analyze the effect of different catalysts such as Na and K on biomass liquefaction under a supercritical environment. The central hypothesis of this project is that Na and K will polymerize complex sugars and lignins at higher rates than without catalysts. The REU participant will examine the effect of pressures, temperatures, residence time, and catalysts on liquid and gas yields.

Supercritical phase Fischer-Tropsch synthesis (Dr. Christopher Roberts)

Fisher-Tropsch synthesis (FTS) represents an enabling technology option for the conversion of biomass to liquid fuels and chemicals, thereby providing greater value potential than simple combustion processes. FTS involves surface catalyzed polymerization reactions of dissociatively adsorbed C1 monomers (from CO adsorption on the catalyst) in the presence of hydrogen over metal catalysts, typically Co, Fe or Ru catalysts. The REU participant will investigate the design of custom FTS reactor configurations and catalyst architectures that enable influence over the hydrocarbon product composition under highly non-ideal thermodynamic conditions that affect the adsorption/desorption equilibria on the catalyst surface. Systematic experimental investigations will be performed to identify and validate suitable processing schemes specific to biomass derived synthesis gas for fuels and middle distillate chemicals production with particular focus on the effects of phase behavior and nonideal thermodynamics using supercritical phase FTS process.

Modeling and Optimization for Liquid Fuels Production (Dr. Mario Eden)

Biochemical processes, such as hydrolysis of polysaccharides followed by fermentation, can utilize only the cellulose and hemicellulose fractions of biomass. Lignin, a major constituent of biomass, cannot be biochemically converted to liquid fuels. On the other hand, gasification can utilize all biomass including lignin. Biomass gasification followed by Fisher-Tropsch synthesis can be used to produce liquid fuels equivalent to petroleum based gasoline and diesel. The REU participant will work on systems integration and optimization techniques to determine optimal pathways for biomass to produce the highest value of liquid fuels while meeting greenhouse gas emission targets and minimizing fuel production cost. The REU participant will use Aspen Plus® process engineering software to perform necessary analyses.

Thermochemical Conversion of Biomass Fedstocks (Dr. Oladiran Fasina)

Based on the vast amount of biomass resources (about 1.3 billion tons per year) available in the country, the USDA and U.S. Department of Energy estimated that energy from biomass feedstocks (e.g. energy crops, forest resources and forest residues) can be used to replace up to 30% of imported crude oil. However, the conversion of these biomass feedstocks into fuels, heat, power and chemical products has been identified as one of the technical barriers, and has limited biomass energy utilization in the country. The bottlenecks that have been identified in the thermochemical conversion process include optimization of the conditions for syngas production from biomass feedstocks (especially cellulosic feedstocks) and process residues. The thermochemical process is crucial to the successful substitute of biomass energy for imported fossil fuel because of its ability to convert lignin portion of the biomass into synthetic gas. The REU student will investigate the effect of heating rate, carrier gas, particle size, moisture content and biomass feedstock on thermal decomposition rate, syngas composition and concentration.

Last Updated: Nov 12, 2013