Steve Spence
Guest
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 Posted: Fri Jan 02, 2004 8:00 am Post subject: WISCONSIN TEAM ENGINEERS HYDROGEN FROM BIOMASS |
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WISCONSIN TEAM ENGINEERS HYDROGEN FROM BIOMASS
http://www.news.wisc.edu/releases/7766.html
MADISON - In the search for a nonpolluting energy source, hydrogen is often
cited as a potential source of unlimited clean power. But hydrogen is only
as clean as the process used to make it. Currently, most hydrogen is made
from fossil fuels like natural gas using multi-step and high-temperature
processes.
Now, chemical engineers at the University of Wisconsin-Madison have
developed a new process that produces hydrogen fuel from plants. This source
of hydrogen is non-toxic, non-flammable and can be safely transported in the
form of sugars.
Writing this week (Aug. 29) in the journal Nature, research scientist Randy
Cortright, graduate student Rupali Davda and professor James Dumesic
describe a process by which glucose, the same energy source used by most
plants and animals, is converted to hydrogen, carbon dioxide, and gaseous
alkanes with hydrogen constituting 50 percent of the products. More refined
molecules such as ethylene glycol and methanol are almost completely
converted to hydrogen and carbon dioxide.
"The process should be greenhouse-gas neutral," says Cortright. "Carbon
dioxide is produced as a byproduct, but the plant biomass grown for hydrogen
production will fix and store the carbon dioxide released the previous
year."
Glucose is manufactured in vast quantities -- for example, in the form of
corn syrup -- from corn starch, but can also be made from sugar beets, or
low-cost biomass waste streams like paper mill sludge, cheese whey, corn
stover or wood waste.
While hydrogen yields are higher for more refined molecules, Dumesic says
glucose derived from waste biomass is likely to be the more practical
candidate for cost effectively generating power.
"We believe we can make improvements to the catalyst and reactor design that
will increase the amount of hydrogen we get from glucose," says Dumesic.
"The alkane byproduct could be used to power an internal combustion engine
or a solid-oxide fuel cell. Very little additional energy would be required
to drive the process."
Because the Wisconsin process occurs in a liquid phase at low reaction
temperatures (227 degrees C., 440 degrees F.) the hydrogen is made without
the need to vaporize water. That represents a major energy savings compared
to ethanol production or other conventional methods for producing hydrogen
from fossil fuels based on vapor-phase, steam-reforming processes.
In addition, the low reaction temperatures result in very low carbon
monoxide (CO) concentrations, making it possible to generate fuel-cell-grade
hydrogen in a single-step process. The lack of CO in the hydrogen fuel
clears a major obstacle to reliable fuel cell operation. CO poisons the
electrode surfaces of low-temperature hydrogen fuel cells.
At current hydrogen yields, the team estimates the process could cost
effectively generate electrical power. That, according to the Wisconsin
researchers, assumes a low-cost biomass waste stream can be efficiently
processed and fed into the system.
To be truly useful, the team says several process improvements must first be
made. The platinum-based catalyst that drives the reaction is expensive and
new combinations of catalysts and reactor configurations are needed to
obtain higher hydrogen yields from more concentrated solutions of sugars.
# # #
-- Jim Beal (608) 263-0611, jbeal@engr.wisc.edu
--
--
Steve Spence
Renewable energy and sustainable living
http://www.green-trust.org
Donate $30 or more to Green Trust, and receive
a copy of Joshua Tickell>s "From the Fryer to
the Fuel Tank", the premier documentary of
biodiesel and vegetable oil powered diesels. |
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Dr. Bob
Guest
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| Posted: Fri Jan 02, 2004 9:37 pm Post subject: Re: WISCONSIN TEAM ENGINEERS HYDROGEN FROM BIOMASS |
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"Steve Spence" <sspence@green-trust.org> wrote in message
news:3ff379ed_2@newsfeed.slurp.net...
[quote]WISCONSIN TEAM ENGINEERS HYDROGEN FROM BIOMASS
http://www.news.wisc.edu/releases/7766.html
MADISON - In the search for a nonpolluting energy source, hydrogen is
often
cited as a potential source of unlimited clean power. But hydrogen is only
as clean as the process used to make it. Currently, most hydrogen is made
from fossil fuels like natural gas using multi-step and high-temperature
processes.
Now, chemical engineers at the University of Wisconsin-Madison have
developed a new process that produces hydrogen fuel from plants. This
source
of hydrogen is non-toxic, non-flammable and can be safely transported in
the
form of sugars.
Writing this week (Aug. 29) in the journal Nature, research scientist
Randy
Cortright, graduate student Rupali Davda and professor James Dumesic
describe a process by which glucose, the same energy source used by most
plants and animals, is converted to hydrogen, carbon dioxide, and gaseous
alkanes with hydrogen constituting 50 percent of the products. More
refined
molecules such as ethylene glycol and methanol are almost completely
converted to hydrogen and carbon dioxide.
"The process should be greenhouse-gas neutral," says Cortright. "Carbon
dioxide is produced as a byproduct, but the plant biomass grown for
hydrogen
production will fix and store the carbon dioxide released the previous
year."
Glucose is manufactured in vast quantities -- for example, in the form of
corn syrup -- from corn starch, but can also be made from sugar beets, or
low-cost biomass waste streams like paper mill sludge, cheese whey, corn
stover or wood waste.
While hydrogen yields are higher for more refined molecules, Dumesic says
glucose derived from waste biomass is likely to be the more practical
candidate for cost effectively generating power.
"We believe we can make improvements to the catalyst and reactor design
that
will increase the amount of hydrogen we get from glucose," says Dumesic.
"The alkane byproduct could be used to power an internal combustion engine
or a solid-oxide fuel cell. Very little additional energy would be
required
to drive the process."
Because the Wisconsin process occurs in a liquid phase at low reaction
temperatures (227 degrees C., 440 degrees F.) the hydrogen is made without
the need to vaporize water. That represents a major energy savings
compared
to ethanol production or other conventional methods for producing hydrogen
from fossil fuels based on vapor-phase, steam-reforming processes.
In addition, the low reaction temperatures result in very low carbon
monoxide (CO) concentrations, making it possible to generate
fuel-cell-grade
hydrogen in a single-step process. The lack of CO in the hydrogen fuel
clears a major obstacle to reliable fuel cell operation. CO poisons the
electrode surfaces of low-temperature hydrogen fuel cells.
At current hydrogen yields, the team estimates the process could cost
effectively generate electrical power. That, according to the Wisconsin
researchers, assumes a low-cost biomass waste stream can be efficiently
processed and fed into the system.
To be truly useful, the team says several process improvements must first
be
made. The platinum-based catalyst that drives the reaction is expensive
and
new combinations of catalysts and reactor configurations are needed to
obtain higher hydrogen yields from more concentrated solutions of sugars.
# # #
-- Jim Beal (608) 263-0611, jbeal@engr.wisc.edu
--
--
Steve Spence
Renewable energy and sustainable living
http://www.green-trust.org
Donate $30 or more to Green Trust, and receive
a copy of Joshua Tickell>s "From the Fryer to
the Fuel Tank", the premier documentary of
biodiesel and vegetable oil powered diesels.
[/quote]
This is very nice but somewhat backward science. If you can make methanol,
alkanes, ethelyne glycol and other useful commodities listed in the process
why the hell yould you make hydrogen? There is no point in hydrogen, given
all of it>s negatives, if the carbon in the cycle is already accounted for
and you are not adding net CO2 to the atmosphere which is one major
advantage of bio-cycles. Methanol alone is a convienient, useful, liquid
fuel that that carries energy without the density penalties of hydrogen.
Hydrogen within the process is more useful as a componenet for synthesizing
larger molecules but it is not likely to become a major direct output of the
process.
Dr. Bob |
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