November 9, 2012
By Kerri Jansen
Full Source Article: http://www.wasterecyclingnews.com/article/20121109/NEWS02/121109939/university-students-invent-way-to-curb-wood-waste
By Kerri Jansen
Full Source Article: http://www.wasterecyclingnews.com/article/20121109/NEWS02/121109939/university-students-invent-way-to-curb-wood-waste
Courtesy, Wikimedia CommonsStudents from the University of Washington developed technology to convert logging waste into a valuable soil additive.
Courtesy, Jenny KnothA mobile kiln consists of heat-resistant panels that are assembled around a pile of logging waste, which is then ignited to create biochar.
When a forest is harvested by loggers or cleared for development, any woody debris that can't be sold is typically heaped into huge "slash piles" and left in place.
Although an emerging biomass industry is siphoning some of that material to biomass burners for energy, limitations on that market mean most of the woody waste is disposed of by open burning, a process that "does a good job of creating bad air quality," said Craig Rawlings, president of Forest Business Network.
Students from the University of Washington decided they could do better.
"We know it's worth something, and we don't want to just leave it there, and we don't want to just burn it," UW forester Jenny Knoth said.
Knoth was part of an interdisciplinary team sponsored by the National Science Foundation that developed a technology to turn woody biomass into a profitable product called biochar. Biochar, charcoal made from plant material, is highly valued as a soil amendment; it improves soil productivity by increasing water-holding capacity and sequestering carbon, Knoth said. The team's technology, a mobile kiln that is assembled around a slash pile, converts woody waste into biochar onsite, greatly reducing transportation and other costs.
The team initially intended to use the charcoal it generated for energy, but discovered there was a higher demand for biochar as a soil amendment, Knoth said. She and two other students startedCarbon Cultures, a company to promote the technology and raise money by selling biochar.
The technology evolved from a heat-resistant blanket thrown over woody debris to portable panels that are assembled around a slash pile, forming a kiln that cooks woody waste at temperatures to about 1,100 degrees Fahrenheit (600 Celsius). Because the kiln limits the amount of oxygen that can reach the material, the biomass decomposes by pyrolysis, forming charcoal.
One unit, which measures five feet in diameter and is about five feet tall, can process its contents in less than two hours, Knoth said. Several units can be running at the same site at once. The process has a 30% conversion rate; 70% of the woody mass goes away, much being water. And the kiln technology produces less gases and particulates like methane, carbon dioxide and smoke, Knoth said.
"[By using] this process of pyrolysis, we … now have a product, and we're not just converting biomass into [carbon dioxide]. … And the other really main, important thing is we're reducing the particulates and the emissions," Knoth said.
In addition to turning waste into a resource and reducing emissions, Knoth hopes the technology can help make forest fires less severe by expanding the conditions under which slash piles can be burned. If slash piles aren't dealt with in time, they can provide additional fuel for dangerous forest fires. Although the technology has not yet been approved by natural resources officials, Knoth hopes they'll be able to prove the kiln is a "safer way of reducing this waste problem in the woods."
Knoth and her colleagues have been testing the technology in an experimental forest owned by the university. The technology's first public demonstration is planned for early November. At this time, the company is focusing on selling biochar, but it is looking into renting or selling kilns in the future, Knoth said.
Forest Business Network's Rawlings said the organization has been following the group's technology as it develops. He sees it being adopted by a wide range of forestry interests, from logging companies to government agencies.
Woody waste "is something that the industry and forest landowners are always dealing with because it's always a cost and it's always a problem," Rawlings said. "I think it takes a lot of tools to address problems, and I think that would be a really viable tool for forest land managers and loggers that have to deal with logging slash."
Contact Waste & Recycling News reporter Kerri Jansen at kjansen@wasterecyclingnews.com or 313-446-6098.
When a forest is harvested by loggers or cleared for development, any woody debris that can't be sold is typically heaped into huge "slash piles" and left in place.
Although an emerging biomass industry is siphoning some of that material to biomass burners for energy, limitations on that market mean most of the woody waste is disposed of by open burning, a process that "does a good job of creating bad air quality," said Craig Rawlings, president of Forest Business Network.
Students from the University of Washington decided they could do better.
"We know it's worth something, and we don't want to just leave it there, and we don't want to just burn it," UW forester Jenny Knoth said.
Knoth was part of an interdisciplinary team sponsored by the National Science Foundation that developed a technology to turn woody biomass into a profitable product called biochar. Biochar, charcoal made from plant material, is highly valued as a soil amendment; it improves soil productivity by increasing water-holding capacity and sequestering carbon, Knoth said. The team's technology, a mobile kiln that is assembled around a slash pile, converts woody waste into biochar onsite, greatly reducing transportation and other costs.
The team initially intended to use the charcoal it generated for energy, but discovered there was a higher demand for biochar as a soil amendment, Knoth said. She and two other students startedCarbon Cultures, a company to promote the technology and raise money by selling biochar.
The technology evolved from a heat-resistant blanket thrown over woody debris to portable panels that are assembled around a slash pile, forming a kiln that cooks woody waste at temperatures to about 1,100 degrees Fahrenheit (600 Celsius). Because the kiln limits the amount of oxygen that can reach the material, the biomass decomposes by pyrolysis, forming charcoal.
One unit, which measures five feet in diameter and is about five feet tall, can process its contents in less than two hours, Knoth said. Several units can be running at the same site at once. The process has a 30% conversion rate; 70% of the woody mass goes away, much being water. And the kiln technology produces less gases and particulates like methane, carbon dioxide and smoke, Knoth said.
"[By using] this process of pyrolysis, we … now have a product, and we're not just converting biomass into [carbon dioxide]. … And the other really main, important thing is we're reducing the particulates and the emissions," Knoth said.
In addition to turning waste into a resource and reducing emissions, Knoth hopes the technology can help make forest fires less severe by expanding the conditions under which slash piles can be burned. If slash piles aren't dealt with in time, they can provide additional fuel for dangerous forest fires. Although the technology has not yet been approved by natural resources officials, Knoth hopes they'll be able to prove the kiln is a "safer way of reducing this waste problem in the woods."
Knoth and her colleagues have been testing the technology in an experimental forest owned by the university. The technology's first public demonstration is planned for early November. At this time, the company is focusing on selling biochar, but it is looking into renting or selling kilns in the future, Knoth said.
Forest Business Network's Rawlings said the organization has been following the group's technology as it develops. He sees it being adopted by a wide range of forestry interests, from logging companies to government agencies.
Woody waste "is something that the industry and forest landowners are always dealing with because it's always a cost and it's always a problem," Rawlings said. "I think it takes a lot of tools to address problems, and I think that would be a really viable tool for forest land managers and loggers that have to deal with logging slash."
Contact Waste & Recycling News reporter Kerri Jansen at kjansen@wasterecyclingnews.com or 313-446-6098.
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