Hans Henrik Hansen wrote:
> Et emne, medierne i disse dage viser stor opmærksomhed - men tilsyneladende
> mener alle, at brinten via brændselsceller skal (delvis) omsættes til
> elektricitet(?)
> Men er dette nu eneste (praktiske) mulighed?
> Hvad ville mon være til hinder for direkte afbrænding af brinten ('brintfyr'
> i villakælderen?) - eller udnyttelse som brændstof i en 'klassisk'
> forbrændingsmotor?
>
Hej Hans
Det er "misforstået" - det hedder sprit/ethanol-samfundet - her er hvorfor:
Kommer fra ing.dk-tråden:
http://www.ing.dk/apps/pbcs.dll/news_message?Kategori=debat&ThemeID=47227&GroupID=972491&InReplyTo=1108196
Her er også en diskussion og en udkast til økonomiske betragtninger
vedr. (ethanol->brint->SOFC-brændelsecelle)-biler.
Ethanol er et temmeligt stabilt stof i forhold til brint og benzin.
Bl.a. fordi det har en høj fordampningsvarme. Herudover er ethanol
rimeligt ugiftigt/uskadeligt. Det kan "lagres" i almindelige dunke hvis
det skulle være.
Så er brint-samfundet indenfor rækkevidde - ethanol som lager (og i
drinks?) - og når der er brug for elektrisk energi (biler, huse...)
sendes ethanol ind i den opfundne "reaktor" og ud kommer brint. Næste
kendte skridt er at sende brint ind i en brændselscelle:
2004-02-16, ScienceDaily: New Reactor Puts Hydrogen From Renewable Fuels
Within Reach:
http://www.sciencedaily.com/releases/2004/02/040214081412.htm
Citat: "...The first reactor capable of producing hydrogen from a
renewable fuel source - ethanol - efficiently enough to hold economic
potential has been invented by University of Minnesota engineers. When
coupled with a hydrogen fuel cell, the unit - small enough to hold in
your hand - could generate one kilowatt of power, almost enough to
supply an average home, the researchers said...if you used ethanol to
make hydrogen for a fuel cell, you would get 60 percent efficiency..."
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Her er opskriften på hvordan ethanol laves om til brint:
12 February 2004, Physicsweb: Fuel cells turn to alcohol.
Researchers in the US and Greece have invented a reactor that can
produce hydrogen from ethanol:
http://www.physicsweb.org/article/news/8/2/6
13 February 2004 Boozy reactor hikes hydrogen hopes:
http://www.nature.com/nsu/040209/040209-13.html
Citat: "..."Ethanol in car engines is burned with 20% efficiency [dette
gælder også diesel og bensin], but if you used ethanol to make hydrogen
for a fuel cell, you would get 60% efficiency," says Schmidt. Ethanol
can usually only be burnt if it is completely free of water - and
getting the water out is an energy-intensive process. Schmidt's reactor
works with wet ethanol..."
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Jan 7, 2004, H2cars: Schwarzenegger Will Have Californian Hydrogen
[måske fra ethanol] Highway Built:
http://www.h2cars.biz/artman/publish/article_390.shtml
Renewable Fuels Association (RFA). Ethanol Report -- February 9, 2004:
Ethanol use reduced greenhouse gases by 5.7 M tons in 2003:
http://www.ethanolrfa.org/ereports/er020904.html
American Coalition for Ethanol:
http://www.ethanol.org/
http://www.hydrogenconference.org/
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Vigtigt spørgsmål: hvor fås ethanol fra? Anden udfordring: Hvordan
gemmes el-overskud?:
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Mulig fremtid: x*brint + y*CO2 -> n*ethanol.
CO2 kunne fås fra CO2 opsparing ved afbrænding af ethanol ved at gemme
det på måske samme måde som man fjerner CO2 på rumstationer/u-både?
Brinten få fra "energioverskud" eller "opsparing" fra vindmøller,
vandkraft, solceller.
Bemærk: Sålænge CO2 til dannelse af (m)ethanol ikke kommer fra ny
fossilt afbrændning, er den dannede ethanol CO2-neutral.
Ethanol Fuel Futures From Green Energy:
http://www.ethanolcredits.com/
Citat: "...Global is currently working on a process which takes hydrogen
and CO2 to make ethanol. Ethanol is a relatively safe and benign fuel
which can be produced in a eco-friend manner...Ethanol is easy to store
and environmentally friendly... Existing wind turbines currently produce
electricity which goes back into the grid. The utilities purchase this
energy at a fraction of what they sell it for to the public. Typically,
the purchase price is so low, that the economics of installing a wind
turbine do not provide a net return..."
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Nutidig: ethanol fås effektivt fra affalds- stivelse og cellulose:
Georgia Biofuel Resources.
Any starch or sugar crop, however, can now be used to make ethanol.
http://www.google.dk/search?q=cache:www.eere.energy.gov/state_energy/tech_biomass.cfm%3Fstate%3DGA
Virkede ikke 040222:
http://www.eere.energy.gov/state_energy/tech_biomass.cfm?state=GA
Citat: "...Current ethanol production uses only about 7% of the crop.)
Any starch or sugar crop, however, can now be used to make ethanol.
In the long term, ethanol could be made from dedicated energy crops of
fast-growing trees and grasses such as poplars and switchgrass...."
Mindst et olieselskab har næse for ethanol::
8 May 2002, Shell invests in green fuel technology:
http://www.olsc.ca/news/shell_invest_5_8.php
Citat: "...The Royal Dutch/Shell Group (Shell) announced today that it
has purchased an equity stake in Iogen Energy Corporation [
http://www.iogen.ca/ ], a world-leading bioethanol technology company..."
1998-10-20 UF Biotech Breakthrough Drives World's First
Biomass-To-Ethanol Plant
http://www.sciencedaily.com/releases/1998/10/981020074004.htm
Citat: "...Ingram's microorganism produces a high yield of ethanol from
biomass such as sugar cane residues, rice hulls, forestry and wood
wastes and other organic materials..."The new technology will allow
ethanol to become economically competitive with fossil fuels for the
first time,"...the world's first genetically engineered E. coli bacteria
capable of converting all sugar types found in plant cell walls into
fuel ethanol for automobiles..."
BIOMASS ENERGY:
http://www.sustainableenergy.qld.edu.au/fact/factsheet_10.html
Citat: "... The team says that when their process is optimized it should
be able to produce electricity at around four cents per kilowatt-hour,
rivalling the costs of conventional electricity...."
Ethanol from Cellulose: Too Good To Be True?
http://www.daviesand.com/Perspectives/Forest_Products/Ethanol/
Citat: "... A Department of Energy (DOE) brochure (
http://www.ott.doe.gov/biofuels/pdfs/ethanol.pdf ) says that ethanol is:
* A domestically produced liquid fuel from renewable, virtually
inexhaustible domestic resources
* A nonfossil transportaion fuel that contributes little, if any, net
carbon dioxide to the atmosphere during production and use
* A high-octane fuel that can contribute substantially to the U.S.
automotive fuel supply
* A fuel that an be used as a blend, a component of ethyl tertiary butyl
ether (ETBE), or as a pure fuel, with excellent efficiency and performance
* A potentially clean-burning fuel that reduces smog and emissions of
carbon monoxide
..."
Cruising the Ethanol Highway.
(Originally published in the Los Angeles Times, February 15, 2004):
http://www.ilsr.org/columns/2004/021504.html
Citat: "...Three years ago, California's cars used no ethanol. Last
year, the state used about 700 million gallons. There's no reason that
California can't take this beginning and make the state the leader in
ending the nation's reliance on fossil fuels. The executive order should
be "ethanol highways," not "hydrogen highways."..."
Estimating the Net Energy Balance of Corn Ethanol. An Economic Research
Service Report by Hosein Shapouri, James A. Duffield and Michael S.
Graboski:
http://www.ethanol-gec.org/corn_eth.htm
Citat: "... Each gallon of ethanol produced domestically displaces 7
gallons of imported oil. In addition, production of ethanol is energy
efficient, in that it yields nearly 25 percent more energy than is used
in growing the corn, harvesting it, and distilling it into ethanol..."
How Much Energy Does It Take to Make a Gallon of Ethanol?
David Lorenz and David Morris. August 1995:
http://www.carbohydrateeconomy.org/library/admin/uploadedfiles/How_Much_Energy_Does_it_Take_to_Make_a_Gallon_.html
Citat: "... Our analysis again concludes that the production of ethanol
from corn is a positive net energy generator. Indeed, the numbers look
even more attractive now than they did in 1992...Table 1:Energy Used to
Make Ethanol From Corn and Cellulose (Btus per Gallon of Ethanol)...Our
conclusion is that under the vast majority of conditions, the amount of
energy contained in ethanol is significantly greater than the amount of
energy used to make ethanol, even if the raw material used is corn..."
http://www.osti.gov/subjectportals/
http://directory.google.com/Top/Science/Technology/Energy/Renewable/Biomass_and_Biofuels/
Mange adresser:
Energy Sources and Storage:
http://members.shaw.ca/legg/g_energy_sources.html
mvh/Glenn
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