by George Couch From Atlanta, Georgia, to Appleton, Wisconsin, to Cypress Bend, Arkansas, to Madison, Wisconsin, one word often overheard when forest products people talk business is “biorefinery.” “The biorefinery concept sparks considerable interest because it could represent the solution to several major problems facing both forest managers and the forest products industry,” said Chris Risbrudt, Ph.D., director of the USDA Forest Service Forest Products Laboratory (FPL). “With forest biomass used as feedstock, biorefineries could produce a variety of fuels and high-value chemicals that could help pay for desperately needed forest management activities. At the same time, they could also reduce energy costs while creating new sources of income for the pulp and paper industry,” Risbrudt said.
That latter benefit put biorefinery on the agenda at an international conference on nanotechnology and the forest products industry in Atlanta in April and at a meeting on energy conservation in Appleton in May. The Atlanta conference was sponsored by TAPPI, an international trade association of the pulp, paper, packaging and converting industry, and FPL. The Appleton meeting, cosponsored by the Center for Technology Transfer (recently renamed CleanTech Partners, Inc.), Focus on Energy, Wisconsin Paper Council, and TAPPI, showcased environmentally friendly approaches to reducing industrial energy costs and fossil fuel usage. Two types of biorefinery are contemplated. A stand-alone biorefinery uses heat and chemical processes to completely convert woody biomass into fuel-grade ethanol, syn-gas, commodity chemicals, plastics feedstock, pharmaceuticals and other high-value chemicals. An integrated biorefinery, installed as part of a pulp mill, extracts and converts some components prior to pulping and converts waste byproducts of the pulping process. Some of the syn-gas and other fuels produced by the refinery would be used in the pulping process. Biorefineries are a logical development of the forest products industry for several reasons. The industry already controls much of the raw material and necessary infrastructure. Pulp and paper mills, for example, are geared to collect and process biomass. Also, the industry itself, which has been hit hard by new global competition, would benefit significantly. Benefits extend beyond the forest products industry. By preserving high-paying skilled jobs in many rural communities, U.S. national and regional economies would be strengthened. And because using forest material is carbon-neutral, using it in place of fossil fuels would reduce greenhouse gas emissions. Use of forest material would improve the diversity and security of the nation’s energy supply and ease dependence on foreign fossil fuel. Forest products mills are located throughout the country, generally close to the supply of biobased fuels. And biomass is an abundant, renewable, sustainable resource. Cypress Bend, Arkansas, might become the site of an integrated biorefinery. Potlatch Corporation announced early this year that it was studying the feasibility of a commercial-scale integrated biorefinery at its Cypress Bend pulp and paperboard mill. Company vice president Harry Seamans said that preliminary estimates indicated a biorefinery could reduce natural gas usage at the mill by 1.6 million MMBTU (about 1.6 billion cubic feet) per year and reduce purchased electricity by 80,000 MWH per year. That’s enough natural gas to supply 20,000 homes and enough electricity to power as many as 8,000 homes. As currently envisioned, Potlatch would bring agricultural and forest waste biomass from throughout the Mississippi Delta and southeast Arkansas to the Cypress Bend mill, where gasification and catalytic processes would convert it to a crude oil to be further refined into fuel products and other chemicals. The company is currently in the process of completing the feasibility study. At FPL in Madison, Wis., several research projects aim at helping make the forest biorefinery concept a practical reality that will benefit the nation’s forests as well as the forest-based industry. One project under the direction of research microbiologist William R. Kenealy, Ph.D., has led to a new pretreatment for wood chips that reduces the electrical energy required for the thermal mechanical pulping process used to make paper, releases fermentable sugars from the chips that can be used to make ethanol, and can result in stronger paper after the chips are pulped. The pretreatment process, which is covered by a joint provisional patent with Biopulping International, Inc., involves treating the chips with heat and a chemical. The process, according to Kenealy, is both technically and commercially feasible. In another project at FPL, microbiologist and senior scientist Tom Jeffries, Ph.D., has worked with specialized strains of yeast that are capable of fermenting xylose in woody biomass for producing ethanol, xylitol and other byproducts. In an integrated biorefinery, the xylose would be extracted prior to pulping, and some of the ethanol so produced would be used to provide heat and generate electricity for the pulp mill and paper plant. Last year, Xethanol Corporation licensed rights to Jeffries’ patented process (see NewsLine, Fall 2005, vol.4, issue 4). Another project underway at FPL is evaluating pretreatment of wood chips prior to pulping or being used in the manufacture of medium density fiberboard (MDF). One method studied extracted large amounts of xylose, which in a biorefinery could then be converted to ethanol. Other studies are looking at new and unusual or other high-value chemicals that can be produced in a biorefinery using waste feedstock or byproducts from pulp and paper mills. “Our challenge is to discover more high-value chemical products that can be produced from woody biomass, especially those products that can only be produced from the unique lignocellulosic materials that need to be removed from our nation’s forests,” said Ted Wegner, Ph.D., assistant director at FPL. Advancing the forest biorefinery idea is one of seven core technology platforms of the Agenda 2020 Technology Alliance, which seeks to accelerate research and the demonstration and deployment of breakthrough technologies. The other platforms are: nanotechnology, breakthrough manufacturing and technologies, next-generation fiber recycling and utilization, positively impacting the environment, advancing the wood products revolution, and a technologically advanced workforce. Originally launched in 1994 by AF&PA and the Department of Energy to promote energy efficiency in forest products manufacturing, Agenda 2020 is an industry-led partnership with government and academia that seeks to advance the forest products industry through innovation in processes, materials and markets. Industry is represented by the American Forest & Paper Association (AF&PA), the national trade association of the forest products industry. Additional participants in Agenda 2020 include the Society of Wood Science and Technology, the Forest Products Society, TAPPI, and the USDA Forest Service.
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