SUNY-ESF's Biorefinery Process
Fayetteville-Manlius high school senior Kammi Balaji (right) explained to reporters how they select only the needed components from the wood extract.
After pressure-cooking wood chips in water at very high temperatures, SUNY-ESF graduate student Ashutosh Mittal (center) opens the valve to release a brown colored liquid containing sugar and acetic acid. Dr. Thomas Amidon (standing left).
Christopher Wood unfolds the respective membrane layers so television cameras can show how the separation process works.
SUNY-ESF undergraduate student Christopher Wood (left) points out the pump, tubing and membrane where the sugar and acetic acid is separated. Dr. Thomas Amidon (kneeling right).
Dr. Thomas Amidon, Chair of SUNY-ESF's Faculty of Paper Science and Engineering, is interviewed by reporters from WIXT Channel 9, News 10 Now TV, the Associated Press as well as (not in picture) WTVH Channel 5, WSTM Channel 3 and WSYR radio.
Turning New York's Wood into the Energy of the Future
"We know our sources of fossil fuel aren't going to last forever," Dr. Thomas Amidon said. "The new Biorefinery process will allow us to substitute a sustainable energy source: wood."
During the last few years, Amidon collaborated with students ranging from a home-schooled high school student to ESF doctoral candidates to devise a new and subtler method for separating wood into its components.
Chief among those components is cellulose, the polysaccharide (sugar) that is the single strongest, most widely used component of woody plants. In the context of a paper mill, cellulose becomes pulp for use in making paper. The second largest component of hardwood trees is the polysaccharide xylan, which is primarily dissolved in the pulping process.
"The real value in that sugar," Amidon said, "was never exploited. Once fermented, the sugar xylan can produce ethanol, which can be used in cars instead of, or in combination with, traditional gasoline."
Although the energy factor is the focus of attention now, as the state steps up its development of alternative fuel sources, there is a second benefit to the process. In addition to extracting sugar from the wood, scientists can separate out the wood's acetic acid, which is used primarily in manufacturing. A major use of acetic acid is the manufacturing of polyvinyl acetate, a plastic used in many aspects of home construction, and many other consumer products. The commercial value of acetic acid is nearly three times that of ethanol: 45 cents per pound as opposed to 18 cents per pound.
The process was developed in ESF's Walters Hall, home to the Faculty of Paper Science and Engineering. Ordinary wood chips are mixed with water and heated at high temperatures for a specified length of time. That time can be shortened if the chips are first subjected to biopulping, a process that allows natural wood-decaying fungi to munch through the lignin that binds the cellulose in the wood. That process is also the subject of research at ESF.
"One of the advantages to the process," Amidon said, "is that is does not use any harsh chemicals."
"Water is the solvent we use," Amidon said. "It's my preferred solvent because if it gets loose in the world, it's just water and the world knows how to deal with it."
The watery solution that remains after the chips are removed is then forced through a membrane that separates the sugars from the water. The acetic acid is removed the same way.
"The trees are here and they can provide year-round employment," Amidon said. "You can also extract these components from grasses, but grasses go dormant in the winter and they're difficult and expensive to store for use in a year-round process. And trees are dense. They can be shipped and stored economically, and they are more efficient energy collectors than annual crops. After the desired components are extracted, the residue can be burned or gasified for combined heat and power uses."
The work, while still in the testing phase, has received support from International Paper, the world's largest paper company, and from Lyonsdale Biomass, a wood-fueled energy producer in Lyons Falls. Representatives of both companies stated in letters of support that they believe the process has significant promise of increasing the profitability of their operations. International Paper has indicated it is a willing partner in exploring technology transfer in the biorefinery work. Lyonsdale has expressed interest in what the company calls "the potential positive impact" of the process on the company's ability to convert woody materials to energy .
In addition, the ESF team has demonstrated the process for scientists from the National Renewable Energy Laboratory in Colorado.
The process is a natural fit for New York state, Amidon said, because the sugars in hardwood trees are simpler than those found in softwood trees. "New York is a hardwood state," he said. "There is a little bit of softwood and a lot of hardwood."
And the process is not choosy about which hardwood trees it uses. Maples, common in the state's forests, work just fine, he said. But so do the willow biomass crops that are being developed by ESF researchers and their colleagues as a commercial crop for energy uses, such as at the Lyonsdale facility.
"If you consider the concept of removing sugars and acetic acid from willow biomass and then burning or gasifying what's left over from that process, the economics of growing willow as an energy crop are significantly improved," Amidon said.