A container of bio oil, produced by the UW research team. Credit: University of Washington

The dead trees of the world’s forests could be a valuable and efficient source of a kind of oil, according to new research published by a team of scientists at the University of Washington.

Fast pyrolysis, the process of heating wood at extreme temperatures in oxygen-less environments to create “bio oil,” would be a viable source of energy with a new method presented by the researchers in the journal Fuel.

The method involves breaking down woodchip-sized pieces – a significant improvement from tiny wood pellets just 1 to 2 millimeters in length, they write.

“We came up with a different way to converting wood into oil,” said Fernando Resende, a senior author, assistant professor of bioresource science and engineering at UW. “Not only do we want to reduce the costs, but we are hoping to increase the value of what we produce so we have a better chance of making it commercial.”

The system involves grinding down bigger hunks of wood down to the woodchip size, and then putting them on a rotating surface below a stainless steel plate heated to extreme temperatures.

Fast pyrolysis generally heats small pieces of organics material, such as wood, to 500 degrees Celsius in oxygen-free spaces. The resulting vapor is then cooled into a liquid fuel – the “bio oil.” (Although such fuel is used in some European hospitals for heating, it has not yet been proven to be viable in transportation fuels).

The UW team proposes cylindrical mobile units which would sit on a small flatbed truck used to process the oil out in wooded areas, they said.

A particular use would be in the American West, where more than 40 million acres of forest have been destroyed by the mountain pine beetle, they said. Such dried-out remains from an infestation would be more easily converted in oil fuel, and could present a unique opportunity for the new technique, they said.