Posted on 08/02/2002 7:43:06 AM PDT by Paradox
Carbon dioxide turned into hydrocarbon fuel |
||||
19:00 31 July 02 | ||||
Exclusive from New Scientist Print Edition | ||||
A way to turn carbon dioxide into hydrocarbons has caused a big stir at an industrial chemistry conference in New Brunwick, New Jersey. Nakamichi Yamasaki of the Tokushima Industrial Technology Center in Japan says he has a process that makes propane and butane at relatively low temperatures and pressures.
While his work still needs independent verification, if he can make even heavier hydrocarbons, it might be possible to make petrol. It has carbon chains that are between five and 12 atoms long - butane is four atoms long.
The work suggests the tantalising prospect that CO2, the main greenhouse gas, could be recycled instead of being pumped into the atmosphere.
Many people have tried before to make hydrocarbons by mixing carbon with hydrogen gas in a reaction chamber at very high temperatures, but yields have always been pitiful. Yamasaki has used hydrochloric acid as his source of hydrogen ions.
He bubbles the CO2 into a reaction vessel (see graphic) where it is heated to about 300 °C at 100 times atmospheric pressure. The heat and pressure are low enough, says Yamasaki, to make it feasible to scale up the reaction so it can run on a power station's waste heat.
Using iron powder as a catalyst, Yamasaki says he has made substantial amounts of methane, ethane, propane and butane, which he was able to vent off as gases when the mixture cooled. If he can improve the catalyst's performance he is hopeful of making heavier hydrocarbons such as petrol, too.
William Siegfried, who has lead similar experiments at the University of Minnesota in the twin cities of Minneapolis and St Paul, says his group was only able to make methane at far higher temperatures. But his process also used a nickel-based alloy as a catalyst, rather than iron.
Siegfried's group was investigating whether natural methane deposits might have formed chemically with the metal in rocks acting as a catalyst rather than forming from the decay of rotting biological material over aeons.
Unless Yamasaki's technology can make the more valuable heavier hydrocarbons such as petroleum, which are liquid at room temperature, it will not be much more use than present-day bioreactors, in which bacteria that like to feed on CO2 are induced to produce methane. "Organisms have a special talent for that kind of reaction," says Siegfried. |
||||
Eugenie Samuel, Boston |
||||
For more exclusive news and expert analysis every week subscribe to New Scientist print edition. |
||||
'Fraid not. The reason why we buy oil from the Middle East is because it is cheaper there than anywhere else in the world. Coming up with yet another way to manufacture artificial oil won't change that. We can't change the laws of economics or thermodynamics; all we can change are the governments of the Middle East.
Capt. Planet finally has a purpose!
Both HCl and chlorine are used industrially everyday throughout the world. Lots of materials that are potentially dangerous are used under safe conditions (f'rinstance, jewelers use cyanide as a cleaning agent, from what I understand of their craft). Don't know how much it costs, but my old high school stockpiled plenty of HCl tablets for use in lab.
The worries are marginal. Let's get some verification on this and tell the towel-heads to go pound sand up their %*$@&!!!! :-)
Or you could just harness the CO2 from his mouth and pump it back into his nose and definitely solve one problem.
Only sufficient for a Master's degree from M.I.T.
And you?
Nice renewable-resources find!
Yup. And what is the energy cost and/or dollar cost to make Hcl?...
I was recently asked to review a German patent(0055134A1). The engine was built and tested by BMW and it worked.
Basically the idea is you carry a big tank of water and feed aluminum wire into the tank, where it is reacted using a spark and the reaction Al + 3H2O --> Al2O3 + 3H2 allows free hydrogen to be burned in a modified engine with incoming air.
This is a redox reaction. Aluminum is being oxidized by the water, and the water is being reduced by the aluminum to make hydrogen.
In this reaction we have two moles of aluminum (54 grams) reacting with three moles of water (54 grams) to produce one mole of aluminum oxide (102 grams) plus 3 moles of hydrogen (six grams). So to make one pound of hydrogen, you will need to scale this by a factor of 75.6: 4.08 kilograms of aluminum (9 lb), 4.08 kilograms of water (again 9 lb), producing 7.71 kilograms of Al2O3 (17 lb) and one pound of hydrogen.
Aluminum costs about 70 cents per pound, so the aluminum cost will be $6.30 for each pound of hydrogen created.
The heating value of gasoline is 114,000 BTU/gallon or +9,475 calories per gram. This is 4,297,765 calories per pound, or 17,055 BTU/lb.
Each pound of hydrogen is worth 60,190 BTU. So hydrogen liberates about 3.5 times as much energy per pound as gasoline. The problem is that gasoline costs about $1.60 per gallon at present, which is the same as $11.40 per cubic foot, or $0.239 per pound.
Since hydrogen gives 3.5 times as much energy per pound as gasoline, we need 1/3.5 times as many pounds of hydrogen to do the same job. This is 0.29 times. But the cost of making hydrogen from aluminum is $6.30 per pound of hydrogen. So 0.29 times $6.30 says hydrogen made from aluminum costs $1.80 per pound of gasoline equivalent. This is $1.80/$0.239=7.54 times as much on a per pound basis. Gas would have to rise to $12.06/gal before you break even using this system. In other words, the economics get you.
Part of the problem is that refined aluminum requires enormous amounts of electricity to make. From the raw ore to the high-purity aluminum takes huge amounts of energy. In fact, the price of aluminum and the price of electricity track one another and affect one another in a complex way. One can look at this patent as follows: the inventor has invented a very expensive battery which is charged up at the aluminum smelter plant. The charging is the energy cost of making pure aluminum out of rocks.
(Water has a heat of formation of 68,320 calories/mole. This is equivalent to 3795 calories per gram. Aluminum Oxide has a heat of formation of 1675.7 kJ/mole, or 3925.4 calories per gram. The total energy available from this reaction is thus (-3795)-(-3925.4) = +130.4 calories/gram. This energy is not used in the actual engine and all it does is make the water get hot.)
(Water weighs 62.4 lb/ft3. Nine pounds of water liberate one pound of hydrogen and 8 pounds of oxygen. In this system the oxygen is thrown away! It is sequestered in Al2O3. Then more oxygen from the air is used to burn the hydrogen.)
No.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.