Wood chips

Scientists have long been able to derive oils from wood, but until now they have been unable to effectively process it so that it could be used in conventional engines.

Now, researchers at the University of Georgia 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.

In the process, 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.