From: xruiks <kimobook@gmail.com>
Date: 2008/2/20
Subject: [265tom blog] Scientists Would Turn Greenhouse Gas Into Gasoline
To: kimobook@gmail.com
If two scientists at Los Alamos National Laboratory are correct,
people will still be driving gasoline-powered cars 50 years from now,
churning out heat-trapping carbon dioxide into the atmosphere ― and
yet that carbon dioxide will not contribute to global warming.
Skip to next paragraph RelatedDot Earth: Making Fuel From Air - Some
Details (February 19, 2008) Green Freedom (pdf) Hydrocarbons for the
21st Century - The Work of the Loker Hydrocarbon Research Institute
Alexander Ruesche/European Press AgencyIn a proposal by two
scientists, vehicle emissions would no longer contribute to global
warming. The scientists, F. Jeffrey Martin and William L. Kubic Jr.,
are proposing a concept, which they have patriotically named Green
Freedom, for removing carbon dioxide from the air and turning it back
into gasoline.
The idea is simple. Air would be blown over a liquid solution of
potassium carbonate, which would absorb the carbon dioxide. The carbon
dioxide would then be extracted and subjected to chemical reactions
that would turn it into fuel: methanol, gasoline or jet fuel.
This process could transform carbon dioxide from an unwanted,
climate-changing pollutant into a vast resource for renewable fuels.
The closed cycle ― equal amounts of carbon dioxide emitted and removed
― would mean that cars, trucks and airplanes using the synthetic fuels
would no longer be contributing to global warming.
Although they have not yet built a synthetic fuel factory, or even a
small prototype, the scientists say it is all based on existing
technology.
"Everything in the concept has been built, is operating or has a close
cousin that is operating," Dr. Martin said.
The Los Alamos proposal does not violate any laws of physics, and
other scientists, like George A. Olah, a Nobel Prize-winning chemist
at the University of Southern California, and Klaus Lackner, a
professor of geophysics at Columbia University, have independently
suggested similar ideas. Dr. Martin said he and Dr. Kubic had worked
out their concept in more detail than previous proposals.
There is, however, a major caveat that explains why no one has built a
carbon-dioxide-to-gasoline factory: it requires a great deal of
energy.
To deal with that problem, the Los Alamos scientists say they have
developed a number of innovations, including a new electrochemical
process for detaching the carbon dioxide after it has been absorbed
into the potassium carbonate solution. The process has been tested in
Dr. Kubic's garage, in a simple apparatus that looks like mutant
Tupperware.
Even with those improvements, providing the energy to produce gasoline
on a commercial scale ― say, 750,000 gallons a day ― would require a
dedicated power plant, preferably a nuclear one, the scientists say.
According to their analysis, their concept, which would cost about $5
billion to build, could produce gasoline at an operating cost of $1.40
a gallon and would turn economically viable when the price at the pump
hits $4.60 a gallon, taking into account construction costs and other
expenses in getting the gas to the consumer. With some additional
technological advances, the break-even price would drop to $3.40 a
gallon, they said.
A nuclear reactor is not required technologically. The same chemical
processes could also be powered by solar panels, for instance, but the
economics become far less favorable.
Dr. Martin and Dr. Kubic will present their Green Freedom concept on
Wednesday at the Alternative Energy Now conference in Lake Buena
Vista, Fla. They plan a simple demonstration within a year and a
larger prototype within a couple of years after that.
A commercial nuclear-powered gasoline factory would have to jump some
high hurdles before it could be built, and thousands of them would be
needed to fully replace petroleum, but this part of the global warming
problem has no easy solutions.
In the efforts to reduce humanity's emissions of carbon dioxide, now
nearing 30 billion metric tons a year, most of the attention so far
has focused on large stationary sources, like power plants where,
conceptually at least, one could imagine a shift from fuels that emit
carbon dioxide ― coal and natural gas ― to those that do not ―
nuclear, solar and wind. Another strategy, known as carbon capture and
storage, would continue the use of fossil fuels but trap the carbon
dioxide and then pipe it underground where it would not affect the
climate.
But to stabilize carbon dioxide levels in the atmosphere would require
drastic cuts in emissions, and similar solutions do not exist for
small, mobile sources of carbon dioxide. Nuclear and solar-powered
cars do not seem plausible anytime soon.
Three solutions have been offered: hydrogen-powered fuel cells,
electric cars and biofuels. Biofuels like ethanol are gasoline
substitutes produced from plants like corn, sugar cane or switch
grass, and the underlying idea is the same as Green Freedom. Plants
absorb carbon dioxide as they grow, balancing out the carbon dioxide
emitted when they are burned. But growing crops for fuel takes up wide
swaths of land.
Hydrogen-powered cars emit no carbon dioxide, but producing hydrogen,
by splitting water or some other chemical reaction, requires copious
energy, and if that energy comes from coal-fired power plants, then
the problem has not been solved. Hydrogen is also harder to store and
move than gasoline and would require an overhaul of the world's energy
infrastructure.
Electric cars also push the carbon dioxide problem to the power plant.
And electric cars have typically been limited to a range of tens of
miles as opposed to the hundreds of miles that can be driven on a tank
of gas.
Gasoline, it turns out, is an almost ideal fuel (except that it
produces 19.4 pounds of carbon dioxide per gallon). It is easily
transported, and it generates more energy per volume than most
alternatives. If it can be made out of carbon dioxide in the air, the
Los Alamos concept may mean there is little reason to switch, after
all. The concept can also be adapted for jet fuel; for jetliners,
neither hydrogen nor batteries seem plausible alternatives.
"This is the only one that I have seen that addresses all of the
concerns that are out there right now," Dr. Martin said.
Other scientists said the Los Alamos proposal perhaps looked promising
but could not evaluate it fully because the details had not been
published.
"It's definitely worth pursuing," said Martin I. Hoffert, a professor
of physics at New York University. "It's not that new an idea. It has
a couple of pieces to it that are interesting."
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由 xruiks 于 2/20/2008 04:02:00 上午 在 265tom blog 上发表