New Method Developed to Extract Biofuel from Wood

Author:  Doshi Ojus

Date:  May 2007

Scientists at the University of Georgia have developed a process to extract and refine liquid biofuel from wood so that it may be used in conventional diesel engines without extensive modification. The findings come at a time when significant resources in the United States are being channeled into alternative energy research in the hopes of reducing both the country's need for outside oil and its carbon emissions through efficient and economically favorable methods. The researchers, led by Thomas Adams, Director of Faculty of Engineering Outreach Service at UGA, published their findings in the journal Energy and Fuels last week.

"What we're doing is trying to isolate the fuel compounds that exist in bio-oil and extract them," Adams said. "We've used traditional chemical engineering techniques to refine it."

According to the researchers, the process is very easy to carry out. Wood chips--Adams and his colleagues used pine,are subjected to pyrolysis, or heating in the absence of oxygen to cause decomposition, which generates a wood-charcoal and gas. The gas is rapidly condensed to yield a liquid categorized as bio-oil.

"You cannot use bio-oil as crude fuel because it has too much oxygen and water,it's soluble in water. That's why it has not been used in engines," Adams said. In order to be used in diesel engines, the bio-oil must dissolve in bio-diesel, an alternative diesel fuel that is produced from animal fats or vegetable oils. High water and oxygen content, however, prevents this from happening.

After Adams's team conducted chemical treatments, most of the water was removed, and the bio-oil was blended with bio-diesel and tested in conventional diesel engines.

"We've been testing this in engines, and it's a good fuel as far as being in diesel engines," Adams remarked.

The next step, say the researchers, is to measure the fuel's emission characteristics to determine its cleanliness. But by the visible results,the fuel generates no smoke, does not contain sulfur, and leaves less residue in pipes,it is cleaner than conventional diesel. Still, more research is needed as well as a patent on the process.

"It's going to take a while before this fuel is widely available," Adams said. "We've just started on developing a new technology that has a lot of promise."

Written by Ojus Doshi