Roseau, Minn. – Gasifiers can turn crop waste into electricity, but can they turn waste into fertilizer? A project in Minnesota’s northland will find out.
The City of Roseau is sponsoring a demonstration project to gasify biomass, creating syngas. Hydrogen from the syngas will be precipitated through a catalyst to produce ammonia, which could be used as a nitrogen soil amendment. Gasification has converted coal to ammonia, but it’s not been done commercially with biomass.
Michael Sparby, AURI project director, says the 100-kilowatt test gasifier will burn about 1,500 tons of biomass per year — relatively small, but large enough to prove the concept works. Feedstock will come from local sources such as grass-seed screenings and rye, wheat and barley straw.
“If we can prove it works technically and efficiently on a smaller scale, we could increase the size to provide fertilizer to a regional area,” Sparby adds. A one-megawatt unit could consume more than18,000 tons of biomass per year and produce more than 8,000 tons of ammonia.
“It would then be feasible to place similar units around the state to provide nitrogen … a fertilizer source from locally-produced materials that is equal to or cheaper than fossil-fuel based fertilizer, and it would be carbon neutral.”
Mayor Jeff Pelowski and others in the Roseau economic development authority became interested in gasification when Sparby gave a presentation about a system being installed in Williams, Minn. to produce electricity from grass-seed screenings. The group asked about the potential for something similar in Roseau.
“Michael saw the fit for us,” Pelowski says. “We have the feedstock, we have a new industrial park and we have end users for either electricity or fertilizer.”
Minnesota Turfseed Council President Richard Magnusson says there are several grass-seed screening facilities in the region producing low-value leftovers that currently are trucked to a disposal site and burned. “We have a waste stream that’s not being used,” says Magnusson, who grows several varieties of grass seed on 4,000 acres near Roseau.
“We generate about 160 pounds of screenings per acre of seed,” and 2,000 to 4,000 pounds of straw, Magnusson says. “Screenings are an easy first step (for gasification) but with a viable production plant, straw is the big potential.”
Once the project’s demonstration phase is complete, and the concept’s engineering and economic feasibility is determined, the gasifier will be used to power Roseau area schools.
Roseau received a grant from the Minnesota Department of Employment and Economic Development for the project. Other supporters include AURI, U.S. Department of Energy, Farmers Union Foundation, Minnesota Wheat Research and Promotion Council, Minnesota Turf Seed Council, Minnesota Barley Growers Association, Roseau Electric Co-op, Farmers Union Co-op of Roseau and University of North Dakota Energy and Environmental Research Center.
“We are looking at this as an economic development project — the beginning of something larger,” Pelowski says.
Sparby expects the gasifier test burns will start by November 2009.