[Gasification] Pyrolysing compost to make fuel
Roger Samson
rsamson at reap-canada.com
Thu Aug 3 08:52:36 CDT 2006
They would be wiser to make biogas out of farm derived material and
recovering the lignin fraction as a stable organic matter soil amendment.
Biogas is a cheaper and more sustainable option. Mining soils to produce
sustainable energy is a pretty poor trade off.
Germany now has 2700 biogas systems running on manure and energy crops. I
don't understand how the US is so backwards to keep putting all their eggs
in the liquid fuels from biomass basket. It creates the worst fuel cycles
and needs the most subsidies.
Here is a presentation on the german biogas systems that was given recently
in Canada:
> http://www.omafra.gov.on.ca/english/engineer/facts/bg_pres4.pdf
A nice use for compost is to use it for capping landfills, the methane
oxidizing bacteria in the compost eat up most of the escaping methane.
Roger Samson
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Sent: Thursday, August 03, 2006 8:39 AM
To: GASIFICATION at LISTSERV.REPP.ORG
Subject: [Gasification] Pyrolysing compost to make fuel
Iowa State Researchers Convert Farm Waste To Bio-Oil 8/1/2006
Nevada, IA - Samy Sadaka reached into a garbage bag, picked up a mixture of
cow manure and corn stalks, let it run through his fingers and invited a
visitor to do the same.
It wasn't that bad.
That mix of manure and corn stalks had spent 27 days breaking down in a
special drying process. The end result looked like brown yard mulch with
lots of
thin fibers. There wasn't much smell. And it was dry to the touch.
"That's about 20 percent moisture," said Drew Simonsen, an Iowa State
University sophomore from Quimby who's working on the research project led
by
Sadaka, an associate scientist for Iowa State's Center for Sustainable
Environmental Technologies.
Other Iowa State researchers working on the project are Robert Burns, an
associate professor of agricultural and biosystems engineering; Mark Hanna,
an
Extension agricultural engineer; Robert C. Brown, director of the Center
for
Sustainable Environmental Technologies and Bergles Professor in Thermal
Science; and Hee-Kwon Ahn, a postdoctoral researcher for the department of
agricultural and biosystems engineering.
The project is being supported by $190,000 in grants from the Iowa
Biotechnology Byproducts Consortium.
The researchers are working to take wastes from Iowa farms -- manure and
corn stalks -- and turn them into a bio-oil that could be used for boiler
fuel
and perhaps transportation fuel.
"The way I see manure, it's not waste anymore," Sadaka said. "It is
bio-oil."
But it takes a few steps to make that transformation.
First, the manure needs to be dried so it can be burned. Sadaka's idea for
low-cost and low-odor drying is to mix the manure with corn stalks, put the
mix in a big drum, use a small blower to keep the air circulating and use
an
auger to turn the mixture once a day. Within about five days, bacteria and
fungi working to decompose the mix have naturally raised the temperature to
about
150 degrees Fahrenheit. Within another 20 days or so the moisture content
is
down from 60 percent to about 20 percent. Sadaka calls the process
bio-drying.
That makes it possible to move to the next step: rapidly heating the
mixture
in a bubbling, fluidized bed reactor that has no oxygen. It's a process
called fast pyrolysis. The process thermochemically breaks the molecular
bonds in
the mixture. It produces charcoal that can be used to enrich soil. And it
produces vapors that are condensed to a thick, dark bio-oil.
Preliminary tests indicate every kilogram of dried mixture produces .2 to
.5
kilograms of bio-oil depending on the operating conditions.
Sadaka said the energy content of dry manure is 12 to 18 gigajoules per
ton.
Canada's Office of Energy Efficiency says one gigajoule of electricity will
keep a 60-watt bulb continuously burning for six months. Sadaka figures if
half the animal manure in the country were processed into bio-oil, that
would
produce the equivalent of 45 million tons of oil.
Sadaka is experimenting with the process in 900-liter drums at the Iowa
Energy Center's Biomass Energy Conversion Center in Nevada. So far, he has
dried
a mixture of cow manure and corn stalks. Next he'll test the process with
poultry manure. And then he'll try pig manure.
This fall he'll work with Dave Struthers, a Story County farmer whose
family
runs a 1,000-sow, farrow-to-finish farm east of Collins, to try the
bio-drying process on a farm.
Struthers said the farm's pigs live in hoop buildings and their manure is
mixed with bedding material. That mixture is applied to the surface of crop
ground as fertilizer.
He's working with Sadaka to convert some of the farm's manure into bio-oil
because he supports alternatives to petroleum.
"And there may be more value in using manure as a fuel source than a
fertilizer source," Struthers said.
Sadaka is convinced this process can help solve some of Iowa's challenges
with agricultural wastes while producing renewable energy. "My goal," he
said,
"is to keep on demonstrating this for all the farmers around."
SOURCE: Iowa State University
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