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Fractionation Of Corn Stover With Effective Shredding And Separation, Jiechao Ma

Open Access Dissertations

A corn stover shredder using a flail type knife and tine shredding mechanism was designed, fabricated, and tested with the objective of improving the shredding extent with corn stover. Two machine designs (open hood with exit chute and closed hood with slots) and three moisture content levels (5, 40, and 70% w.b.) were studied. Shredding was more effective (higher leachate ion conductivity index representing better access to plant nutrients) with the closed hood with slots design than with the open hood design (p<0.001). Extent of shredding was proportional to moisture content at the time of shredding. The attempt to process the corn stover at 70% w.b. was promising as it resulted in a highest leachate ion conductivity (LIC) index of 86%, which is comparable to that of hammer-milled dry stover. Two speeds for the shredding rotors (no-load speeds of 1300 and 700 rpm) were tested with the three moisture levels and the closed-hood with slots design but shredding speed did not affect LIC (p>0.25). To ascertain the tissue make-up of stover samples (rind, pith, leaf, and husk percentages) a multi-trait …

Enzymatic Liquefaction Of Untreated Corn Stover, Neal N. Hengge

Open Access Theses

There is an ever increasing need for renewable alternatives to fossil fuels derived from petroleum. This makes feedstocks in the form of lignocellulosic biomass attractive substrates for the production of ethanol and value added chemicals. However, the economics of converting lignocellulosic materials involve high processing costs attributed with pretreatment of the biomass and the use of enzymes for saccharification. Corn stover was obtained for the examination of an upstream processing step to transform the material into a pumpable slurry for subsequent pretreatment and saccharification. Biomass liquefaction was carried out using the enzyme Depol 692L (Biocatalysts, Wales, UK) at 50°C with …

Fast-Pyrolysis Of Biomass Related Model Compounds: A Novel Approach To Experimental Study And Modeling, John Charles Degenstein

Open Access Dissertations

Fast pyrolysis is a potentially attractive method for converting biomass to a low energy-density liquid (bio-oil) that can be further upgraded for use as fuel. Currently there is no agreement concerning the reaction pathways and mechanisms for pyrolysis of any individual component of biomass. This information is important for optimization of the fast-pyrolysis process. The work was divided into four areas, 1--development and validation of analytical methods and reactors, 2--the utilization of these methods to study pyrolysis of biomass and related models, 3--use of available biomass conversion pathways to propose potential integration with the existing fuel and chemicals markets, and …

Density Functional Theory Calculations Complement Mass Spectrometry Experiments In The Investigation Of Biomass Fast Pyrolysis And Ion-Molecule Reaction Mechanisms, Mckay Whetton Easton

Open Access Dissertations

Biomass fast-pyrolysis, or the rapid heating in the absence of oxygen, is a promising method for biomass conversion necessary for a renewable energy economy. Although kinetic models of cellulose pyrolysis have existed since the 1970s, current models and hypothesized reaction networks fail to explain the product distribution even for a simple model compound, the cellulose dimer, cellobiose. A novel approach of using mass spectrometry to instantly characterize fast pyrolysis vapors allows for identification of initial products to help delineate the reaction pathways that dictate the final product distribution of fast pyrolysis of biomass and model compounds. The use of this …

Targeted Products From Fast-Hydropyrolysis And Hydrodeoxygenation Of Biomass, Ian Tad Smith

Open Access Theses

Previously, the H2Bioil process was proposed as a possible way to convert sustainably available intact biomass into liquid fuels. The optimization of this process and possible synergies with other biomass conversion processes are presented in this thesis.

The selectivity of the PtMo hydrodeoxygenation catalyst was tuned using two different hydrogen partial pressures: 25 bar, and 2.5 bar. This effect was studied on cellulose and intact biomass samples to determine the effect that hydrogen has upon the retention of aromatic compounds found in intact biomass. These experiments show that it is possible for the hydrogenation activity of the PtMo catalyst to …

High Pressure Micro-Scale Studies Of Fast-Hydropyrolysis And Catalytic Hydrogenation Of Biomass And Related Model Compounds, Harshavardhan Choudhari

Open Access Dissertations

Biomass is a major source of renewable carbon which can be converted to hydrocarbon fuel with the aim of reducing the dependence on fossil based sources. Fast pyrolysis of biomass followed by catalytic hydrodeoxygenation of bio-oil is considered a promising biomass conversion route to produce drop in hydrocarbon fuels. The H2Bioil process was proposed as an integrated high pressure fast hydropyrolysis and catalytic vapor phase hydrodeoxygenation (HDO) pathway for utilizing biomass to produce high energy density fuel. During fast hydropyrolysis biomass is rapidly heated to generate a complex mixture of compounds with high oxygen content (35-40 wt %). In the …

Lab-Scale Fast-Hydropyrolysis And Vapor-Phase Catalytic Hydrodeoxygenation For Producing Liquid Fuel Range Hydrocarbons From Intact Biomass, Vinod Kumar Venkatakrishnan

Open Access Dissertations

Liquid transportation fuels are primarily produced from petroleum-based non-renewable carbon sources. Sustainably available lignocellulosic biomass, as a renewable form of atmospheric carbon, could be utilized to produce hydrocarbon-based fuels with high energy density. One of the process options for this conversion is the H2Bioil process, where biomass is rapidly heated in a hydrogen environment to produce fast-hydropyrolysis vapors that are catalytically upgraded in downstream hydrodeoxygenation (HDO) to produce hydrocarbons. This process has been modeled to have high carbon and energy efficiencies of ~70% and ~75%, respectively.

This dissertation presents the results of a lab-scale experimental proof-of-concept for the H2Bioil process …

Environmental Tradeoffs In Bioenergy Production And Agricultural Practices, Alicia Lynn English

Open Access Dissertations

The focus of this dissertation is the environmental tradeoffs of stover removal within the Corn Belt. The environmental tradeoffs considered are mainly concerned with managing soil erosion and soil quality. The analysis layers soil characteristics, management strategies and per acre costs using an integrated RUSLE2/WEPS model and an economic optimization model to illuminate a lower bound supply response. Different assumptions were tested in regards to sustainability, prices, and market integration for five states and 18,760 soil types throughout the Corn Belt. Sustainability was defined to limit soil erosion from wind and water to 5 tons/acre/year and the soil organic matter …

Utilization Of Biomass Derived Furans In Value-Added Organics And Heterogeneous Oxorhenium Catalysts For Deoxydehydration Of Diols, Benjamin L. Wegenhart

Open Access Dissertations

As fossil fuels are depleted, there is a growing focus on renewable chemicals based on biomass materials, including both fuels and chemical feedstocks. Current methods for biomass utilization include biological conversion to produce ethanol and various thermochemical routes (gasification, pyrolysis, liquefaction, hydrothermal treatment, etc.). Furfural is one particular chemical that can be obtained from lignocellulosic biomass in good yields through the dehydration of sugar residues. It can be used as a feedstock for chemicals such as furan and THF, or as a platform molecule for making liquid fuels. The objective of this research is to investigate new pathways for the …

Energy Systems Analysis For A Solar Economy, Dharik Sanchan Mallapragada

Open Access Dissertations

The use of solar energy for human needs faces challenges owing to its relatively low energy intensity and intermittent availability, coupled with the constrained availability of renewable carbon and land resources. This study uses systems analysis tools to identify carbon and energy efficient transformations of solar energy for different purposes, including transportation fuels and grid-scale energy storage. These efforts have been complemented with a feasibility analysis of existing fossil-energy and other hybrid pathways.

In an era of limited fossil resources, liquid fuels from sustainably available (SA) biomass could meet the energy needs of the transportation sector. We present a method …

Design And Use Of An Adjustable Clearance Flailing Knife Biomass Shredder To Mechanically Increase Particle Surface Area, Shawn Gregory Ehlers

Open Access Theses

A flailing knife shredder was designed and tested as an alternative to a hammermill for processing biomass. The machine was comprised of two cylinders with four rungs, each with five free-swinging blades. Each of the two cylinders had adjustable clearance hoods and variable speed drives. Energy usage, output characteristics and device capacities were compared with corn stover processed at moisture contents (MC) of 10%, 35% and 50% wet basis (WB). The hammermill produced a more uniform particle size distribution in comparison to the shredder. Accessibility, indicated by conductivity index, to plant constituents, revealed that the method of treatment was not-significant …