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University of Kentucky
Bioenergy and Biofuels Research Topics
SURA Southern Energy Initiative
February 2007
Crops and Feedstock Production
The Science and Engineering for a Biobased Industry and Economy
This multi-state project is directed toward reducing the cost of handling biomass, and
expanding the scientific knowledge leading to significant economic improvements in
biobased products. The project intends to identify educational materials to train a
workforce to support biobased industry. A website has been launched which serves as a
clearinghouse for information related to research on biomass conversion. Contact: Sue
Nokes ([email protected]), Czarena Crofcheck, Mike Montross.
Collection and Characterization of Biomass for Fuel and Chemical Production
Corn stover is a potential feedstock for the production of fuels and chemicals that could
generate additional farm revenue of $70/acre. Corn stover has been characterized to
determine variations in composition so suitable equipment and processes can be
developed. Collection of specific fractions of corn stover (primarily cobs and leaves)
would increase the glucose yields from saccarification of the fractionated stover, while
the stover left behind in the fields (primarily stalks) should provide sufficient erosion
control. Collection of cobs, leaves, and husks could be accomplished with minor
modifications to current combines, considering existing combines provide separation of
corn from cobs, leaves, and husks. Based on recent results, the amount of glucose
released from stover would increase by approximately 21% by selectively collecting cobs
and leaves and leaving stalks and leaves in the field. Preliminary economic analysis
indicates that the ethanol cost could be reduced by 17% if the glucose potential of the
biomass feedstock was increased by selective fractionation.
Contact: Mike Montross ([email protected]), Scott Shearer, Czar Crofcheck.
Biomass Processing and Conversion
Microbially-Based Biofuels and Bioproducts Research
Faculty from the UK College of Agriculture, in collaboration with other scientists, have
been conducting basic research in the area of microbially-based biofuels and bioproducts
since 1995. This research effort is based on the premise that structural plant
carbohydrates (fibrous biomass) can be used as inexpensive and renewable feedstocks for
biologically-mediated conversion processes. Our specific focus has been understanding
and enhancing the use of thermophilic and anaerobic bacteria as bio-catalysts in the
conversion of fibrous biomass to biofuels and other vendable chemicals. The major
research thrusts include: biochemical and molecular characterization of sugar transport in
anaerobic thermophiles, evaluation of thermophilic microbial metabolism at high
pressure in supercritical solvents, development of solid-state culture techniques involving
thermophilic bacteria and fibrous biomass for the production of thermo-stable enzymes,
isolation of ethanol-tolerant strains and subsequent characterization of adaptation to
ethanol using state of the art proteomic approaches, and characterization of cellular
metabolism using metabolomic approaches. Contact: Herb Strobel ([email protected]),
Sue Nokes, Barbara Knutson, and Bert Lynn.
Indirect Thermochemical Conversion of Biomass to Fuels and Chemicals
Similar to coal, biomass can be converted into fuels and chemicals indirectly by
gasification to syngas followed by catalytic conversion to liquid fuels, or directly to a
liquid product. Syngas can be generated from many different biomass sources or used in
blends with other hydrocarbon fuels using well established gasification technology. This
synthesis gas can then be converted to liquid fuels and chemicals via the Fischer-Tropsch
(FT) process. The FT process centers on the reaction of hydrogen with carbon monoxide,
carbon dioxide or mixtures of these to yield one or more types of carbon compound, e.g.,
hydrocarbons, alcohols, esters, acids, ketones, aldehydes, etc. The purification,
separation, conversion or treatment of one or more of the products resulting from the
Fischer-Tropsch synthesis, such as by oxidation, adsorption, solvent extraction, etc., is
also of paramount importance. The Center for Applied Energy Research operates the
largest open-access FT testing and development laboratory in the world, currently
operating 18 stirred reactors, 1 slurry bubble column reactor and several fixed bed
reactors. We are exploring the use of both iron and cobalt based catalysts for syngas
conversion to paraffin, diesel and jet fuels, as well as separation and upgrading of
products. Contact: Rodney Andrews ([email protected]) or Burt Davis.
Biomass liquefaction
Oils produced by pyrolysis are less viscous, and have higher yields at lower cost when
compared to the oils produced by high-pressure liquefaction. For this reason, pyrolysis is
currently the expected route for the industrial conversion of biomass to fuels and
chemicals. However, pyrolysis is unsuited for production of heavy liquid products due to
operating conditions that primarily favor the formation of light oils and gases. A
selective, low severity, non-hydrogenative process may prove to be an economical
method for producing crude oils from biomass, especially when targeting on-site
applications (e.g., at farms, lumber mills, forests, etc.). In this way, the crude bio-oil
could be transported to a centralized facility for refining, making the crude bio-oil quite
similar to crude petroleum, where several products are possible through the refining
process. The process is similar to traditional pyrolysis with respect to the
thermochemical processes taking place, but uses a liquid medium to act as a solvent, to
extract formed products, to provide heat transport and mitigate localized hot spots, and to
act as a carrier fluid for product separation. The concept of extraction-liquefaction was
shown in previously for white oak conversion into a valuable product suite. We are
investigating a novel liquefaction-extraction method for biomass conversion to crude biooil utilizing an extruder-reactor for on site densification of biomass. The proposed
approach aims to utilize biomass on the farm for delayed transport to centralized biorefineries. Given that biomass is expensive to transport, being able to pre-process and
densify the biomass before transport to a centralized bio-refinery will save significant
costs and potentially increase rural income. Contact: Rodney Andrews
([email protected]), Czar Crofcheck, Kunlei Lui, Mark Crocker.
Biofuels Upgrading and Bio-oil Stablization
The crude bio-oils afforded by thermochemical conversion processes such as pyrolysis
are chemically complex and are typified by a high oxygen content. The oxygenated
compounds present in raw bio-oils impart a number of unwanted characteristics such as
thermal instability (reflected in increasing viscosity upon storage), corrosivity and low
heating value. This instability is associated with the presence of reactive chemical
species, notably alkenes, aldehydes, ketones, carboxylic acids and guaiacol-type
molecules. Upon prolonged storage, condensation reactions involving these functional
groups result in the formation of heavier compounds. The quality of bio-oils can be
improved by the partial or total elimination of the oxygenated functionalities present. In
this context, we are studying new approaches for catalyst-assisted stabilization of crude
biomass-derived pyrolysis oils, for the ultimate production of fuels and high value
chemicals. This work is performed in collaboration with the UK Department of
Biosystems and Agricultural Engineering. Contact: Czar Crofcheck
([email protected]) or Mark Crocker.
Biodiesel Production
The production of biodiesel from vegetable oil represents another means of producing
liquid fuels from biomass, and one which is growing rapidly in commercial importance.
Commercially, biodiesel is produced from vegetable oils, including rapeseed, sunflower
and soybean oil, as well as from animal fats. These oils and fats are typically composed
of C14-C20 fatty acid triglycerides. In order to produce a fuel that is suitable for use in
diesel engines, these triglycerides are converted to the respective alkyl esters (with
glycerol as a co-product) by base-catalyzed transesterification with short chain alcohols.
Commercially homogeneous base catalysts are used, such as NaOH. However, solid base
catalysts are attractive on the basis that their use should (i) result in a reduction in the
amount of soaps and salts that need to be removed (thereby improving the quality of the
glycerol co-product), and (ii) enable biodiesel production to be more readily performed as
a continuous process. We are therefore studying the use of a variety solid base catalysts
for this purpose, such as layered double hydroxides. Contact: Mark Crocker
([email protected]) or Czar Crofcheck.
Other work in the area of biodiesel production is focused on utilization of glycerin
byproducts in plant heat and power operations. Novel burner designs are being
developed to allow direct utilization of glycerin for the production of heat and electricity
on site in more efficient manner than is currently available. Contact: Rodney Andrews
([email protected]) or Kunlei Lui.
Producer Gas from Biomass Gasification
An area of biomass utilization we would like to explore is the use of producer gas derived
from biomass gasification as supplemental fuel for landfill gas fired power generation
sets. Along with this, there is a great deal of interest from the electric power industry in
the use of producer gas for use in coal fired power plants for reburn fuel to reduce NOx
emissions. Contact: Kunlei Lui ([email protected]) or Jim Neathery.
Production of Biomass Briquettes as an Alternative Fuel Source
The numerous industrial and process heat boilers found at pulp mills, food plants, and
other industrial sites are relatively small, often less than 25 MW units, which are
essentially unregulated. The substitution of CO2-neutral biomass represents an attractive
approach to decreasing the release of air pollutants such as SOx, NOx, and mercury, as
well as reducing fossil energy consumption in this often overlooked, but significant
industrial sector. One promising approach is to substitute a briquetted fuel manufactured
from the agricultural or wood waste that is generated at or near the industrial site where
the fuel is to be used. In addition to being sustainable and cleaner burning, such a
briquetted biofuel can be more economically stored, conveyed, and processed in existing
equipment. Further, the development of low-cost, briquetting binders from agriculturalprocessing residues would create a market for these low-value byproducts while
decreasing the energy required for the briquetting process. The overall goal of the project
is to produce a premium, durable briquetted biomass fuel from agricultural and wood
wastes that is an attractive alternative energy source for coal-fired boilers. Specific
objectives include: investigate corn stover, fescue, and wood waste as a briquetted-fuel
source; assess the performance of inexpensive binders available from farms and
agricultural-processing facilities (e.g., poultry litter, gum residue from soybean oil
extraction, and distillers grain from ethanol production), determine the energy content,
chemical composition, and strength and attrition characteristics of the biomass briquettes
produced, estimate the economics and net energy balance for briquetted biomass fuels.
Contact: Mike Montross ([email protected]), Darrell Taulbee, Scott Shearer or
Rodney Andrews.
Genomics and Plant Genetics
Renewable Fuels from Tobacco
This research is aimed at genetically engineering tobacco plants for the biosynthesis and
accumulation of specialized branched-chain hydrocarbons known as triterpenes, targeted
compounds with 30 to 34 carbon atoms. These triterpenes are considered the
biogeochemical progenitors to the current day shale oil deposits and are readily converted
to high-grade combustible fuels with current conventional processing methods. We have
already created transgenic plants capable of accumulating 15 carbon terpenes
(sesquiterpenes), and demonstrated that these compounds are derived directly from the
action of photosynthesis and the direct funneling of photosynthetically fixed CO2 into the
biosynthesis and accumulation of terpenes. These oils can be easily cracked into
combustible grade fuels under standard conditions. Overall, 67% of the converted oil has
been shown to convert to gasoline grade fuel, 15% to aviation turbine fuel, 15% to diesel
fuel and a residual of only 3% in previously reported work. Contact: Joe Chappell
([email protected]).
Policy, Commercialization and Relations
Kentucky Rural Energy Consortium
The Kentucky Rural Energy Consortium (KREC) is a partnership involving the UK
College of Agriculture, College of Engineering, and Center for Applied Energy Research;
UL Kentucky Pollution Prevention Center and J.B. Speed School of Engineering; other
Kentucky Universities; the Kentucky Division of Energy and other key state agencies;
and agricultural commodities groups and industry partners. KREC seeks to advance
research on biomass, renewable energy and energy efficiency pertaining to Kentucky
agriculture, rural communities, and industries. KREC was established in 2005, and
awarded 7 competitive research grants in 2006. Contact: Sue Nokes
([email protected]), Don Colliver, Mike Montross, Czar Crofcheck, Rich Gates.
Biomass Education Modules
A workshop was developed for middle-school students to show that decisions related to
renewable energy (or any energy policy for that matter) are not straight-forward. A
learning module was developed for use in classrooms by teachers or as self-paced
learning for students which includes power point slides, craft instructions, and an energy
board game. The website can be accessed at www.bae.uky.edu/biofuels. Contact: Sue
Nokes ([email protected])
Biodiesel and Ethanol Tours
State officials and citizens across the Commonwealth were educated about the production
and utilization of clean/alternative fuels by means of guided tours of ethanol and
biodiesel production facilities, and by the creation of companion “virtual” tours for both
ethanol and biodiesel. The “virtual” tours, entitled The Kentucky Biodiesel Journey and
the Kentucky Ethanol Journey, are both CD-based, movie-like journeys. A web site was
created to distribute the virtual tours and addition information about Biofuels in
Kentucky, www.bae.uky.edu/Biofuels. Contact: Czarena Crofcheck
([email protected])
Commercialization
Many of the projects here, in particular FT catalysis, briquetted fuels, and biomass
liquefaction, are carried out in collaboration with industry. These programs build on the
long standing relationships between the College of Agriculture, the College of
Engineering and the Center for Applied Energy Research in supporting the agriculture,
chemical and power industries in Kentucky and the nation.