Waste not: Fibers

Fiber, fiber, everywhere: Alfalfa stems, aspen, corn stover, culled dry beans, DDGS, grass seed chaff, hazelnuts, oat hulls, peat, poplars, red-top grass, reed canary grass, rye-grass straw, soybean hulls, soybean straw, sugar beet pulp, sunflower hulls, timothy-grass straw, wheat straw, wild rice hulls, willows … the list goes on. Plant fiber — the same organic matter that eons ago became crude oil — offers immense potential for fuels and industrial products.

BIOMASS BURNING

All kinds of Minnesota ag fibers, called biomass, can be used for fuel. The University
of Minnesota is experimenting with burning oat hulls on the Twin Cities campus, and
the Morris campus plans to gasify corn stover. AURI is a leader in this emerging sector,
tackling technical problems such as energy content and burn efficiency, and biomass
handling, processing and storage.

ETHANOL FROM ALMOST ANYTHING

Many types of plant materials supply starch that can be fermented to make ethanol.

PLASTIC AND OTHER PETRO SUBS

If there’s one word that describes the future of ag fibers, it’s plastics. There’s intense
research underway on refining plant materials for all the things that are now made
from petroleum, including polymers, packaging films, foams, adhesives, building
materials, textiles and a host of other manufactured goods.

WOULD-BE WOOD

Ag fibers can also be used as alternatives to wood for making paper, oriented strand
board, and other wood products.

LITTLE BITS

Ag fibers such as beet pulp and DDGS are a source of high value pharmaceutical
sugars.

From waste to watts

Minnesota growers may be first in country to gasify grass-seed chaff for electricity

By Dan Lemke
Grand Forks, ND — The acrid smell of burning grass wafts through the brisk October air as
researchers scurry around a gauge-laden apparatus on a semi-trailer. This small scale gasifier is testing grass-seed chaff as a potential fuel source for electrical generation.

If it works, Northern Excellence Seed, LLC, might fuel its own seed-cleaning plant — reducing or eliminating a $40,000 annual electric bill. More than 40 growers — primarily from Minnesota’s Lake of the Woods and Roseau counties — produce grass seed for Northern Excellence, including ryegrass, Kentucky bluegrass, timothy and native grasses.
 

AURI’s Center for Producer-Owned Energy helped sponsor the five-day test that, if successful, could go beyond fueling one plant to charging up an entire community.

Good gas
Grass biomass smolders inside the mobile gasification unit, while gauges and sensors
capture data on hydrogen, oxygen, methane and carbon dioxide output. “This is some of
the best gas we’ve seen,” says researcher Kyle Martin while checking readings.

The remark draws a smile from Brent Benike, Northern Excellence Seed general manager
who journeyed three hours from Williams, Minn. to Grand Forks, N.D. to witness the burn. The test is being conducted by the Energy & Environmental Research Center at the University of North Dakota in Grand Forks.

Gasification converts solid materials into synthetic gas that can be burned like natural gas in a furnace, turbine or engine. In this case, two types of grass-seed chaff are being tested — from ryegrass and bluegrass. “We’re burning the screenings (as waste) anyway, why not capture the energy?” Benike said.

“Right now we’re getting better quality gas with ryegrass than we can get with wood chips,” says Darren Schmidt, EERC research manager who specializes in biomass. He is evaluating the grass’s emissions, ash and Btu value.

Cool days, cooler nights
Northern Excellence Seed farmers benefit from nearly perfect grass-growing climate —
moderately cool days and even cooler nights — because of their proximity to the 950,000-
acre Lake of the Woods. Along with Oregon and Washington, Minnesota is a national leader in grass-seed production.
 

Perennial grasses produce seeds that are harvested in early summer. The seed head is stripped from the stem and hauled to a seed-cleaning plant where seed is separated from chaff. At the Northern Excellence plant in Williams, seeds are then bagged, shipped across the globe, and sold for home and commercial lawns.
 

The left-over screenings — about 1.25 million pounds — are hauled to a landfill and burned.
Benike estimates that Northern Excellence will generate well over 2 million pounds of
screenings in 2006 — enough to be a reliable biomass-energy source.
 

“Given the whole energy situation in the United States … the timing is definitely right.” Benike says. “It’s renewable, we’re not bringing it in from the Middle East.”

From India to Lake of the Woods
The chaff charring in EERC’s gasification chamber demonstrates a new technology developed in India. The 100-kilowatt gasifier uses suction to capture gas that is cleaned
by a scrubber. The gas could then be run through an engine or turbine to produce heat
or electricity.
 

Northern Excellence is considering installing a similar gasifier at its plant. The growers could save money “by not having to haul screenings away,” says Michael Sparby, AURI project developer. Also, “depending on the size of the gasifier brought in, there could be payback in about four to five years just in energy savings.”

“We need to determine the number of tons per hour that it takes (to run the gasifier), or if we have to bring in biomass from the outside,” Benike says. “We’ll see if this is the size gasifier we would need or if we could bring in a bigger one to power the whole town.”
 

With the screenings yielding 140-Btu gas per cubic foot, it has good potential.
 

But Benike says positive results won’t guarantee Northern Excellence will install a gasifier, as a 100-kilowatt unit would cost more than $150,000. “It still hinges on funding. We’re not sure we want to chew the whole thing ourselves. But it could save labor, fuel, disposal costs, we would gain energy and, if it’s large enough, we’d gain energy for the whole community.” ■

(left) More than 40 northern Minnesota farms, primarily in Roseau and Lake of the Woods counties harvest grass seed for Northern Excellence Seed. The area's cool climate is near perfect for growing grass.

(right) Brent Benike, general manager of Northern Excellence Seed, says grass chaff that is now burned as waste could be burned as energy. “Given the whole energy situation in the United States ... the timing is definitely right.”