Engineering Commons^™

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 …

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 …

Design Of Transgenic S. Cerevisiae For Enzymatic Pretreatment, Mark Aronson, Leyla Yamin, Soo Jung Ha, Jenna Rickus, Michael E. Scharf

The Summer Undergraduate Research Fellowship (SURF) Symposium

Biofuels, combustible fuel produced from fermentation of agricultural biomass by microorganisms, represent one of the best possible paths forward for sustainable energy production. However, inefficiencies in biofuel production create barriers that stand in the way of their widespread adoption. One such barrier is the breakdown of lignin, a biopolymer that exists on the edge of plant cell walls which protects the sugars that are used in fermentation. Currently, lignin is broken down in energy-intensive thermal pretreatment processes. A viable alternative is the expression of lignin-degrading enzymes by synthetic microorganisms that work at standard temperatures, eliminating the need for the high-energy …

The Role Of Surface Area In Catalytic Gasification Of Biomass, Elizabeth A. Wachs, Nitish Kumar, Indraneel Sircar, Prithviraja Basak, Jay P. Gore Phd

The Summer Undergraduate Research Fellowship (SURF) Symposium

Gasification of biomass has the potential to provide a carbon-negative source of liquid fuels. The current limited use of gasification is due in part to the high temperatures necessary to achieve high conversion levels. These temperatures can be lowered by the use of catalysts, but the mechanisms by which catalysts affect the reaction rate are not fully understood. Here, the structural component of potassium carbonate’s role in the gasification process was examined. Samples of pinewood sawdust were impregnated with potassium carbonate, then pyrolyzed with N2 in a fixed bed reactor at 750°C (heater thermocouple reading). Half of the char was …

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 …

Solvent Selection For Liquid-Liquid Extraction Of Acetic Acid From Biomass Hydrolysate, Emma A. Barber, Mahdieh Aghazadeh, Abigail Engelberth

The Summer Undergraduate Research Fellowship (SURF) Symposium

Biofuels are one of the most hopeful alternative energy sources to fossil fuels. However, the processing and production of biofuels needs improvement to be economically competitive in the current market. One drawback is the presence of naturally occurring compounds that decrease the bioethanol production rate and yield; these are called inhibitors. A resolution to this problem is to remove the inhibitors from biomass fermentation broth prior to fermentation. This project examined liquid-liquid extraction (LLE) for removal of acetic acid, a major inhibitor. Initially, a stock solution of glucose, xylose, acetic acid, and water was combined with an additional organic solvent …

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 …