WSU On Solid Ground | June 2014

If you’ve ever enjoyed the summertime taste of fish, chicken or steak grilled over charcoal, you have benefited from pyrolysis. The very same technology that produces charcoal is also a cornerstone for making the vision of a commercial, wood-based biofuels industry in the Pacific Northwest a reality.

Scientists like Manuel Garcia-Perez and his graduate students, who study biosystems engineering at WSU, are helping to nurture the emerging biofuels industry by developing pyrolysis technologies.

Through pyrolysis, biomass like wood, grass, and other organic material is exposed to high temperatures in the absence of oxygen. The result is bio-oil, a precursor to biofuel, as well as other useful products like charcoal, or biochar.

“The low-hanging fruit for commercializing the technology to convert biomass to energy comes from sources like construction debris, for example, that are concentrated in one location,” Garcia-Perez said. “But in cases where the biomass is spread out over a large region, as with forestry waste, transportation to a processing facility can be expensive.”

Pyrolysis road show

One solution the wood fuels industry is exploring is the development of mobile pyrolysis units, or reactors, which can process the raw material right where it’s collected in the forest before transporting the resulting bio-oil to a refinery.

Nine WSU graduate students in Garcia-Perez’s lab were invited to share their knowledge of pyrolysis and evaluate the products of two different mobile pyrolysis units developed by Amaron Energy and Western Renewable Technologies during a recent demonstration in Bingen, Washington. The Washington State Department of Natural Resources sponsored the event in order to offer the public and industry a chance to learn about the technology.

In addition to providing background and sharing information about their research projects with more than 120 visitors, the students also collected samples of the bio-oil and biochar for testing back at the lab in Pullman, Washington. How much oil versus biochar did the two units produce? What was the quality of the products, how did the two units compare in terms of pollution? They will share these answers with the Department of Natural Resources and the two companies later this year.

Students, society benefit

In one day, the students collected bio-oil and biochar samples that would otherwise take days or weeks to produce in a lab. Perhaps more valuable, however, was the opportunity for students to meet people in the industry who build pyrolysis systems as well as policymakers who are interested in how the technology might serve society.

“Because we’re usually working on our projects in the lab, it’s hard to get perspective of what the industry wants,” said Brennan Pecha, a doctoral student in Garcia-Perez’s lab. “It was really nice to get a feel for who is actually producing reactors and using research like ours.”

The mobile technology shows promise but Garcia-Perez cautions that it’s not a solution for all types of biomass and situations. Although the mobile units are much larger than those Garcia-Perez has in his lab, their size is a limiting factor for achieving an economy of scale. Another limitation is that the technology to refine bio-oil is not yet at a stage where it is ready for commercialization.

But Garcia-Perez remains hopeful. Ultimately, a wood-based biofuels industry is intended to reduce our reliance on fossil fuels. And when used as a soil amendment in agriculture, biochar can help reduce greenhouse gas emissions by sequestering carbon in the soil.

“Mobile pyrolysis units are not yet commercially viable and the technology to refine bio-oil is still developing, but it has the potential to be a great benefit to society,” he said.

—Sylvia Kantor