Digital Commons Network^™

Thermochemical Conversion Of Biomass To Renewable Fuels, Naijia Hao

Doctoral Dissertations

Valorization of lignocellulosic biomass to renewable biofuels provides a promising solution to address growing concerns regarding energy security and environmental issues. Researchers are breaking the chemical & engineering barriers to efficiently convert lignocellulosic biomass to liquid fuels. The thermochemical deconstruction strategies can be classified into three categories: gasification, pyrolysis, and liquefaction. Pyrolysis and liquefaction are called selective thermal processing which generate liquid products via depolymerization and fragmentation of biomass feedstocks. This dissertation focuses on the pyrolysis and liquefaction of whole lignocellulosic biomass. The liquid products (called bio-oil) are inherently chemical complex, of high oxygen content, low heating values compared to …

Proteome Characterizations Of Microbial Systems Using Ms-Based Experimental And Informatics Approaches To Examine Key Metabolic Pathways, Proteins Of Unknown Function, And Phenotypic Adaptation, Suresh Poudel

Doctoral Dissertations

Microbes express complex phenotypes and coordinate activities to build microbial communities. Recent work has focused on understanding the ability of microbial systems to efficiently utilize cellulosic biomass to produce bioenergy-related products. In order to maximize the yield of these bioenergy-related products from a microbial system, it is necessary to understand the molecular mechanisms.The ability of mass spectrometry to precisely identify thousands of proteins from a bacterial source has established mass spectrometry-based proteomics as an indispensable tool for various biological disciplines. This dissertation developed and optimized various proteomics experimental and informatic protocols, and integrated the resulting data with metabolomics, transcriptomics, and …

Lignin Maximization: Analyzing The Impact Of Different Feedstocks And Feedstock Ratios Using Organosolv Fractionation, Marc Banholzer

Masters Theses

Over-exploitation of fossil fuels coupled with increasing pressure to reduce carbon emissions are prompting a transition from conventional petrochemical feedstocks to sustainable and renewable sourced carbon. The use of lignocellulosic biomass as a feedstock for integrated biorefining is of current high interest, as separation into its component parts affords process streams of cellulose, hemicellulose and lignin, each of which can serve as a starting point for the production of biobased chemicals and fuels. Given the large number of potential sources of lignocellulosic feedstocks, the biorefinery will need to adapt to the supplies available over a normal growing season. Of particular …

An Economic Evaluation Of A Biofuel Supply Chain Utilizing Multiple Feedstocks, Huaqi Zhang

Masters Theses

Biomass is considered as one potential feedstock for biofuel production. However, the high cost of biomass-to-biofuel supply chain, attributed to biomass’s low bulk density and resulting harvest, storage, and transportation challenges, has been a major hindrance to the success of biomass-based biofuel industry. In addition, the issue of dry matter losses during storage for a feedstock has affected biomass quantity and quality if the feedstock is stored for several months after a single harvest in a year. One potential way to improve the economics of biomass supply chain is to reduce storage need and enhance the utilization of harvest equipment …

A Simulation Model Of The “Bio-Depot” Concept In The Context Of Components Of Variance And The “Taguchi Loss Function”, Maximilian Platzer

Masters Theses

The research focuses on the simulation, statistical evaluation, costs, and continuous improvement of supply chains for bio-based materials. A significant challenge of using cellulosic feedstocks for biofuel or bioenergy production is the high per unit costs of final products, e.g., biofuels. The goal of the research is to provide practitioners with useful statistical methods and a simulation Excel template for evaluating the variance and costs associated with the supply chain of bio-based products. Statistical Process Control (SPC), components of variance, Taguchi Loss Function, and reliability block diagrams (RBD) are used in this thesis for the evaluation of the supply chain …

Genetic Modification Of Switchgrass (Panicum Virgatum L.) For Improvement Of Plant Architecture, Biomass Productivity And Sugar Release Efficiency For Biofuel, Wegi Aberra Wuddineh

Doctoral Dissertations

Switchgrass (Panicum virgatum L.) is a leading candidate bioenergy crop for sustainable biofuel production. To ensure its economic viability, tremendous improvements in switchgrass biomass productivity and recalcitrance to enzymatic saccharification are needed. Genetic manipulation of lignin biosynthesis by targeting transcriptional regulators of higher level domains of lignin biosynthesis and other complex traits could alter several bioenergy-desirable traits at once. A three-pronged approach was made in the dissertation research to target one plant growth regulator and transcription factors to alter plant architecture and cell wall biosynthesis.

Gibberellin (GA) catabolic enzymes, GA 2-oxidases (GA2oxs), were utilized to alternatively modify the lignin …

Economic And Environmental Optimization In The Supply Of Switchgrass In Tennessee, Jia Zhong

Masters Theses

The low efficiency of collection, storage and transportation in the switchgrass supply chain has hindered the commercialization of a switchgrass-based biofuel industry, even given its ecological and environmental advantages in carbon sequestrate, soil quality, water use, and pollution pressure. Thus, designing a switchgrass-based supply chain balancing both environmental and economic performance is important to expedite the development of the cellulosic biofuel industry to meet the national energy plan.

The objectives of this study are to 1) determine economic cost and multiple environmental outcomes in feedstock supply chains and 2) identify the relation between the economic and environmental performances. The first …

Nanolayer Polymeric Coatings To Enhance The Performance And Service Life Of Inorganic Membranes For High Temperature-High Pressure Biomass Pretreatment And Other Applications, Vincent C. Kandagor

Doctoral Dissertations

Membrane technology has become increasingly attractive in several applications including water filtration, food industry, oil and gas, and biomedical applications. Most recently the quest for renewable, bioenergy has called for use of membranes in biomass pretreatment and other stages of producing biofuel. The success and advancement of the membrane technology for these various applications has, however, been impeded by the fouling of membranes, which causes the pores in the microporous structure to block, resulting in reduced efficiency, and in some cases, total failure of the membranes system. This challenge leads to a tremendous increase in the cost of using membranes …

Life-Cycle Assessment In Government Policy In The United States, Daniel L. Reed

Doctoral Dissertations

The United States government, both at the Federal and state levels, are continuously relying on emerging technological and methodological tools in order to provide essential information to decision and policy-makers. Life-cycle assessment (LCA) is a rapidly emerging tool for both the private and public sectors. Governments around the world are aggressively looking towards life-cycle information to guide policy and promote environmental issues. LCA’s beginning in the United States dates back to 1969 at the Coca-Cola Company as a innovative way at looking at their beverage container’s impact on the environment. Since then life-cycle concepts have been slowly adapted and accepted …

Impact Of Switchgrass Bioenergy Feedstock Production On Soil Carbon Dioxide Flux And Below Ground Soil Organic Carbon Storage In East Tennessee, Leah Denise Soro

Masters Theses

Bioenergy production from switchgrass has shown promise in restoring degraded soils and helping to mitigate greenhouse gas (GHG) emissions. CO₂ loss and C-sequestration in soils are important topics for research to better understand the environmental impacts of bioenergy crops. The need for more thorough research of the carbon cycle in soils used for bioenergy production precipitated the primary interest of this study. The specific objectives of this study were 1) to measure SOC under switchgrass production in order to predict storage of carbon in soils based on previous cropping history, land management, soil physical characteristics, and time; and to …