Tuesday, June 5, 2007

Oil from wood chips: research in Georgia University


A new, green fuel

A team of UGA researchers has developed a new biofuel derived from
wood chips. Unlike previous fuels derived from wood, the new and still
unnamed fuel can be blended with biodiesel and petroleum diesel to
power conventional engines.

"The exciting thing about our method is that it is very easy to do,"
said Tom Adams, director of the UGA Faculty of Engineering outreach
service. "We expect to reduce the price of producing fuels from
biomass dramatically with this technique."

Adams, whose findings are detailed in a recent edition of the American
Chemical Society journal Energy and Fuels, explained that scientists
have long been able to derive oils from wood, but they had been unable
to process it effectively or inexpensively so that it can be used in
conventional engines. The researchers have developed a new chemical
process, which they are working to patent, that inexpensively treats
the oil so that it can be used in unmodified diesel engines or blended
with biodiesel and petroleum diesel.

Here's how the process works: Wood chips and pellets – roughly a
quarter inch in diameter and six-tenths of an inch long – are heated
in the absence of oxygen at a high temperature, a process known as
pyrolysis. Up to a third of the dry weight of the wood becomes
charcoal, while the rest becomes a gas. Most of this gas is condensed
into a liquid bio-oil and chemically treated. When the process is
complete, about 34 percent of the bio-oil (or 15 to 17 percent of the
dry weight of the wood) can be used to power engines. The researchers
are currently working to improve the process to derive even more oil
from the wood.

Adams pointed out that the new biofuel also offers environmental
benefits. The fuel is nearly carbon neutral, meaning that it does not
significantly increase heat-trapping carbon dioxide in the atmosphere
as long as new trees are planted to replace the ones used to create
the fuel.

The researchers have also set up test plots in Tifton, Ga., to explore
whether the charcoal that is produced when the fuel is made can be
used as a fertilizer. Adams said that if the economics work for the
charcoal fertilizer, the biofuel would actually be carbon negative.

"You're taking carbon out of the atmosphere when you grow a plant, and
if you don't use all of that carbon and return some of it to the soil
in an inert form, you're actually decreasing the amount of carbon
dioxide in the atmosphere," Adams explained. "We're optimistic because
in most types of soil, carbon char has very beneficial effects on the
ecology of the soil, its productivity and its ability to maintain

Although the new biofuel has performed well, Adams said further tests
are needed to assess its long-term impact on engines, its emissions
characteristics and the best way to transport and store it.

Maximizing Research Opportunities

Critical to the success of the research program at UGA is the
construction of badly needed facilities in this area of institutional
strength. The $40 million Paul D. Coverdell Center for Biomedical
Health Sciences, which was completed in 2005, includes two floors of
biomedical research laboratories, a state-of-the-art bioimaging
research center, a 20,000-square-foot rodent-barrier facility and
program offices for BHSI and the College of Public Health. Also, the
College of Veterinary Medicine opened the Animal Health Research
Center in 2006. AHRC houses scientists who study infectious diseases
and toxicity problems that affect human and animal populations.
Additionally, the College of Pharmacy's capital campaign has raised $7
million of the $10 million it committed to build new facilities that
will "bridge UGA and Medical College of Georgia," while the state has
promised to fund $36.5 million of the project. The new
140,000-square-foot Complex Carbohydrate Research Center was dedicated
in February 2004, and its 900 MHz NMR spectrometer became operational
in January 2005.

Office of Vice President for Research and Associate Provost
University of Georgia
609 Boyd Graduate Studies Building
Athens, GA 30602
Phone: 706/542-5969


The use of pyrolysis-derived bio-oil as a diesel-fuel extender or
substitute has long been a goal of the bio-oil research community. In
this paper, a simple system to accomplish that goal is described. The
production of pine-chip-derived bio-oils, the preparation, and fuel
properties of bio-oil/biodiesel blends are presented.
Pyrolysis-condensed liquids were obtained from the pyrolysis of pine
chips and pine pellets in batch and auger slow-pyrolysis reactors.
These liquids were composed of two phases: an oily bottom phase and an
aqueous phase. The removal of most of the water present in the aqueous
phase results in the formation of a second oily phase called, in this
paper, polar oil. The oily bottom phases were more soluble in
biodiesel than the polar oils. Monolignols, furans, sugars,
extractive-derived compounds, and a relatively small fraction of
oligomers were the main bio-oil compounds soluble in biodiesel. Water
and low-molecular-weight compounds responsible for many of the
undesirable fuel properties of bio-oils were poorly dissolved in
biodiesel. Select fuel properties of bio-oil/biodiesel blends, such as
viscosity, density, calorific value, water content, and pH, are

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