Thursday, October 30, 2008

Researcher seeks energy answer in biofuels

A vial of bio-oil in Soria's laboratory

Juan Andres Soria, assistant professor of wood chemistry, is immersed in research to better understand how biofuels can help meet the energy needs of Alaskans. Soria, based at the Palmer Research and Extension Center, spends his time in his lab surrounded by multitudes of glass jars filled with black, stinky liquid. “It looks like oil,” Soria said. And that is the gist of Soria’s work: Can wood be converted to a useful fuel in a cost-effective, safe, and clean manner?

“Nothing is going to trump oil,” Soria said. “But we are consuming our petroleum hydrocarbon resources and the time will come when the supply is low.”

His approach is multifaceted, yet practical. “Because we live in a liquid fuel economy (extraction, transportation, processing, storage, and utilization) the production of liquid fuel is the first logical step,” he said. “We need a new way of looking at biomass. We need to start with the fundamentals.” Alaska has large amounts of woody biomass that could be used in value-added product applications.

Ideally, those forest stands that are merchantable with straight trees of good diameter (eight inches or more at breast height) exhibiting good strength, easily accessible, and able to be processed by machine can be used to rebuild the near- decimated forest products industry in the state. One possibility that has been overlooked in the past is timber stands that have been killed by fire or beetles, or stands that are not ideal candidates for making the boards and fiber products that end up in homes, although using this biomass requires extra steps to remove damaged bark prior to processing.

Soria has been analyzing different woods in locations that were burned between 2000 and 2006. This covers 5.4 million acres in Alaska. “Salvaging the wood will require a new way of looking at things,” Soria said. He has analyzed spruce, birch, and alder, with a variability in moisture content ranging from 6 to 45 percent.

wood samples

In addition to forest stands, there are also brushy, woody species that grow quickly and that can be agricultural crops, managed under intensive conditions for the production of biomass. One drawback in Alaska is that there is no major forest products industry, nor an established technology to use the produced biomass, other than using it as a heating fuel.

Soria cautioned that not all biomass is created equal. “We know we have large amounts of biomass but not all of it is the same,” he said. “We are still learning the fundamentals of Alaska biomass from a chemical standpoint.” Using the same “recipe for cooking” the biomass, Soria has noted more than 300 individual chemicals produced in the liquid biomass. “We have to learn not to treat biomass as the end-all be-all word. Each species has different concentrations of chemicals.”

For the most part, bio-oil research is traditionally focused on pyrolysis, which gives the operator no control over most processing and products. Pyrolytic bio-oil has been proven to power generators and space heaters.

Another approach is liquefaction of biomass using supercritical fluids. Unlike pyrolysis, supercritical fluids can be tweaked to control yields of chemicals and they have much higher liquefaction levels (95 percent). Also, they have greater chemical production and recovery, but the downside is that it is still in the research and development phase and engineering needs for scale up have not been addressed.

Processing can be costly, and is often cited as a criticism for research in biofuels. “What we fail to realize is that we do not pay a single dime for the processing responsible for creating petroleum. Nature has taken care of this over millions of years. In biomass, we have to pay to process biomass into hydrocarbons.” Soria said. He described biofuel production as a race to recreate a process that took nature millions of years to one that takes place in a matter of minutes. Unfortunately, because we rely on petroleum hydrocarbons for the production of not only fuels, but plastics, resins, fertilizers, and solvents among thousands of additional products, alternatives are extremely limited. Other renewable energy sources are not capable of producing complex hydrocarbons (solar, wind, hydro, geothermal, nuclear, and hydrogen produce electricity or hydrogen—not hydrocarbons) so even as we move toward a more diverse mixture of energy, we will have to invest in biomass as the single most effective way of producing those hydrocarbon alternatives to petroleum, Soria said.

Other research that Soria is conducting is in creating a gaseous mixture that can compete with natural gas, and even in internal combustion engines. To produce this requires temperatures as high as 900˚C. “It takes high temperature, air and biomass to generate a gaseous mixture—producer gas,” Soria said. He is currently researching gasification using a downdraft gasifier, analyzing the products from hemlock, yellow cedar, red cedar, and Sitka spruce.

Soria believes small decentralized reactors for both gasification and liquid fuel production will be the best approach in Alaska, once the right technology is found based on the biomass characteristics and niche markets are developed. The challenge of infrastructure is a constant for Alaska, especially the challenges of transportation and storage of biomass. In the meantime, he would like to make the processes fit the current infrastructure and develop a liquid that is closer to the raw petroleum base product. “I’m not trying to reinvent the wheel. I’m trying to find the best of both worlds.” By following this approach, biomass can enter the same infrastructure in place for petroleum, capitalizing on the existing technology, and enabling a renewable source to be introduced in mainstream fossil fuel use technology.

See also:
"Alaska woody biomass,” SNRAS Science & News, July 23, 2008.
• "Biomass for biofuels: not all trees are created equal," by J. Andres Soria, Agroborealis 39(2), winter/spring 2008 (PDF), p. 7.
Biomass Energy, Alaska Energy Authority webpage on energy from biomass, including links and references on biodiesel, municipal waste, and wood and wood waste.
• UAF Forest Products Program, Valerie Barber, director

Soria's research papers on the subject:

Mitchell, B.K., L.L. Ingram, Jr., J. A. Soria, P.H. Steele, D.A. Strobel. (2008) Chemical and physical characteristics of bio-oils from pine and oak feedstocks. Forest Products Society Proceedings. Woody Biomass Utilization: Challenges and Opportunites. pp. 33-38.

Soria, J.A. McDonald, A.G, Shook, S.R. (2008) Wood solubilization and depolymerization using supercritical methanol. Part 1: Process optimization and analysis of methanol insoluble components (bio-char). Holzforschung, Vol. 62 (4), pp. 402–408.

Soria, J.A., McDonald, A.G., He, B.B. (2008) Wood solubilization and depolymerization by supercritical methanol. Part 2: Analysis of methanol soluble compounds. Holzforschung, Vol. 62 (4), pp. 409–416.

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