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43 Comments
- geminitojanus, on 10/12/2007, -0/+13Solution actually is "Grow some Algae", as they commit the CO2->Fuel operation much quicker, fast enough to be viable for a fuel system.
- guytoronto, on 10/12/2007, -3/+12In a nutshell: Synthetic photosynthesis.
"It is a long time to practical applications."
Solution: Plant a tree. - inactive, on 10/12/2007, -3/+12This just in from the future: Trees everywhere dying due to lack of atmospheric CO2...
- clide, on 10/12/2007, -0/+9Go down to a local paintball shop and you can get your very own bottle of liquid carbon dioxide.
- mkayatta, on 10/12/2007, -0/+6Longer carbon chains like methanol?! Something fishy about that statement... 1 + 0 = 1.
- Ramble, on 10/12/2007, -1/+6I never knew plants could make long chain alkanes or alkenes.
- Smwbigboss, on 10/12/2007, -1/+5Yes, lets plant a tree on the space shuttle to mars. Wood is an excelent fuel source.
- bbrosemer, on 10/12/2007, -0/+4However it takes alot more energy then it is worth to turn the CO2 into fuel. Thanks Orgo...
- tjl2015, on 10/12/2007, -1/+5Liquid carbon dioxide is just as worthless a fuel as gaseous carbon dioxide. They're talking about taking carbon dioxide and reacting it, probably with water, to produce combustible fuels. It's essentially the opposite of combustion.
Combustion:
(Hydrocarbons)+O2 => CO2 +H2O + energy
This process:
CO2 + H20 +energy => (Hydrocarbons) +O2
Now, obviously you will never get more energy out then you put in. This whole cycle isn't some giant perpetual motion device. They're talking about using hydrocarbons as an energy storage device, like a battery, rather than an energy source, like a nuclear reactor. However, I think the article kind of misses the point of this whole technology.
Right now, to fight global warming, we need to stop increasing the level of carbon dioxide in the atmosphere. The main way to do this is to stop emissions. The process they're describing does nothing to help fight global warming. One idea put forth to lower emissions is to sequester the CO2 emissions from coal and gas power plants deep underground. This might work, if they can keep it from leaking out. What this article implies is that by using the waste CO2 of the power plants to produce fuel we will somehow reduce our overall CO2 emissions. This is total garbage. Because when you burn the fuel produced THE CARBON DIOXIDE ENDS UP IN THE ATMOSPHERE ANYWAY!
All this does is make it so the CO2 is released from a tailpipe rather than a smokestack. There is only one way you could use this technology to reduce CO2 levels. It would involve taking CO2 directly from the atmosphere via some sort of large-scale CO2 scrubber. The CO2 would be taken from the atmosphere, turned into hydrocarbons, then released again as it was burned. The whole cycle would be carbon-neutral. However, the problem is that there is no efficient way to remove large amounts of CO2 directly from the atmosphere. CO2 is very dillute. having a concentration from 300 to 400 parts per million. You can use cryogenic distillation to remove it from the air, but the process will be incredibly inefficient and would require enormous amounts of clean energy, from nuclear or renewable sources, to the point of being completely economically nonviable.
If they want to use this technology to give the owners of the coal plants a new product to sell, perhaps that would work. But for actually combating global warming, the technology is worthless. Personally, I agree with some of the above comments. We already have a natural way of turning atmospheric CO2 into hydrocarbons, organic photosynthesis. Nature has perfected this incredibly intricate process over 3 billion years of continuous evolution. It's much better to use ethanol produced from biomass, or bio-diesel or other fuels produced from refined algae. These processes have a carbon-neutral fuel cycle, and are the only way to combat global warming while using the existing infrastructure of internal combustion engines. - elnerdo, on 10/12/2007, -3/+7I always figured that liquid carbon dioxide was really, really, really, really hard to come by.
- geekee, on 10/12/2007, -0/+3Doesn't it take more energy to liquify CO2 than you'd get from it using this process?
- noodlez, on 10/12/2007, -0/+3they also used gaseous carbon dioxide.
- Lososaurus, on 10/12/2007, -0/+2It's easy enough to come by for millions of paintballers to use it.
- inactive, on 10/12/2007, -1/+3So does that mean that Al Gore can *truly* be carbon neutral if this comes into production? I mean...he *does* spout a whole lot of C02. ;)
- dreamcaster, on 10/12/2007, -1/+3Under the right conditions, CO2 gas can be made into a liquid form quite easily.
- geminitojanus, on 10/12/2007, -1/+3HEPA filters remove contaminants from air (particles, dust, some germs), it doesn't remove CO2, which is much, much harder to remove from air (as air itself is partly made of up CO2).
- AnalystX, on 10/12/2007, -0/+2vikingcoder: "efficient CO2 scrubbing in enclosed environments - e.g. submersibles"
article: "Chemist Gabriele Centi of the University of Messina in Italy uses solar energy [...] much like photosynthesis"
Care to rethink that statement? - carve, on 10/12/2007, -0/+2You will have to add more energy to the CO2 than you'll get back by re-burning your new fuel.
- coolbru, on 10/12/2007, -1/+3Decesioner? Sounds like something along the lines of "I am become death, destroyer of worlds".
- Mrkamikaze, on 10/12/2007, -0/+1When mixed with other substances like water....
- geminitojanus, on 10/12/2007, -0/+1"I never knew plants could make long chain alkanes or alkenes."
Most can't, but they do make long proteins and carbohydrates (sugars), which are easily converted to fuel, and they make all kinds of various mol. weight carbon compounds which can be converted through a chemical process into diesel or ethanol. - dmegan, on 10/12/2007, -3/+4In a statement today President Bush, commenting on the discovery of making energy from CO2 declared that taking CO2 from the atmosphere is a federal crime.
"The CO2 was generated as the direct result of them hard workin' peoples in the Oil Industry therefore the right to use it for further energy production is theirs. I'm sure they would sell you the CO2 for $2.99 a gallon though." After all, I'm the decesioner and I make the decisions" - inactive, on 10/12/2007, -0/+1@bbrosemer
The whole point of this is to have a renewable liquid fuel. We can get all the energy we need through sources like solar but it would be better to run our cars off of something liquid. - christianw, on 10/12/2007, -0/+1isnt sir richard branson about to release some new fuel that will work on internal combustion engines and burns 100% clean? i coulda sworn i read that recently.
- AnalystX, on 10/12/2007, -0/+1Yes. Fortunately, "Centi's team decided to try to use carbon dioxide in its natural form: gas. [...] Centi presented his new gas phase research on September 13 at the American Chemical Society meeting in San Francisco."
- willcode4beer, on 10/12/2007, -0/+1Why not use solar panels to power a sabatier reactor.....?
- AnalystX, on 10/12/2007, -0/+1"We already have a natural way of turning atmospheric CO2 into hydrocarbons, organic photosynthesis."
I agree this technology is not as efficient as organic photosynthesis, but you can't put plants everywhere. This would be more effective in densely populated cities where plants can't be grown and harvested, and where CO2 pollution is at its highest concentration. - AnalystX, on 10/12/2007, -0/+1"The appropriate EM spectrum could be produced"
With what, electricity? From where? Something that produces CO2 as waste? Your comment about an "absoptive compound with a finite effectiveness" doesn't make any sense in the light of your assertion that the EM spectrum could be produced. The last I checked, electricity stored in batteries or converted from fuel is also finite. - treskel, on 10/12/2007, -0/+1length of carbon chain in a CO2 molecule:1
length of carbon chain in a methanol molecule:1 CH3OH :P
wow. talk about an informed digg. - elnerdo, on 10/12/2007, -0/+1No, he is not about to release a 100% clean fuel.
- AnalystX, on 10/12/2007, -0/+1"Everything is finite. Comparative efficiencies are what matter."
Yes, and that's why I brought the matter up. You said, "efficient CO2 scrubbing" and there's nothing more efficient than using energy from sunlight directly. If you're going to use electricity to generate light for this process, why wouldn't you just use that energy to convert Calcium carbonate back into Calcium hydroxide? The inefficiency in either case is that you lose energy by converting sunlight into electricity. However, in your suggested case, you lose even more in converting from electricity to light. - bbrosemer, on 10/12/2007, -0/+1@tjl your not going to deprotinate water. Unless you put a whole load of energy into it.
- Corvidae, on 10/12/2007, -0/+1Personally I think the last comment in the article was the most relevant. We could launch a few of these reactors to mars before we send a manned flight. Then when we get there, have a fresh supply of fuel waiting for the ride home. It could cut the weight required for the trip tremendously, especially if re-used for future missions.
It might also be possible to float one on a balloon above venus, with a rocket motor to bring the fuel back up to orbit. Not sure of the usefulness there, but it's an idea. - skipjacker, on 10/12/2007, -1/+2No doubt. A "C" with no other "C"'s is a long chain.
- vikingcoder, on 10/12/2007, -0/+0> With what, electricity? From where?
Batteries & nuclear fission powered electricity generation springs to mind.
> electricity stored in batteries or converted from fuel is also finite.
Everything is finite. Comparative efficiencies are what matter. - vikingcoder, on 10/12/2007, -0/+0Aboard the space shuttle, they use a Regenerative Carbon Dioxide Removal System. It uses a metal oxide sorbent rather than slaked lime. The sorbent is regenerated by flowing air at approximately 400ยบ F at 7.5 scfm through each expended canister for a duration of 10 hours. It is then cooled down for 4 hours.
http://www.hamiltonsundstrand.com/hsc/proddesc_display/0,4494,CLI1_DIV25_ETI5338_PRD776,00.html
That is 127,500 L = 5688.8 moles = 165 kg of air. The atmosphere has a specific heat capacity of ~1 J/(g*K). Assuming raising the gas from STP, that is raising the temperature ~180 K. That requires a total of ~8 KWh of energy. It can handle a total of ~3 kg of CO2. That works out to >1.6 KWh / kg of CO2.
If the energy / CO2 fixed requirements of the photoelectrocatalytic reactor are less than that, it is a more efficient system. Another important matter is how fast & steady the fixing reaction is. This is all a moot discussion though, until we know what the specifics of the reactor are. - vikingcoder, on 10/12/2007, -0/+0No. That comment is irrelevant.
The appropriate EM spectrum could be produced and directed into the photoelectrocatalytic reactor. A simple electrical process that utilized a catalyst would be much better than having to rely on a absoptive compound with a finite effectiveness or a complicated mechanical process that could break down.
The resultant fuel is irrelevant since combustion requires oxygen and puts the CO2 right back into the air. There was no comment on how effectively the process removed CO2 from a given volume of gas mixture though. - cyroxos, on 10/12/2007, -1/+1Yea, that statement there turned me away from this article.
- davidrools, on 10/12/2007, -2/+2yeah this could start some global cooling haha
- vikingcoder, on 10/12/2007, -1/+0I'm seeing a good potential for efficient CO2 scrubbing in enclosed environments - e.g. submersibles, space vehicles, moon habitations, etc...
- vikingcoder, on 10/12/2007, -1/+0grr... Digg went funky and didn't reply properly.
- piofo, on 10/12/2007, -7/+0A scientist from Italy.. they don't have any scientists there, they're all too busy ***** their sisters and stealing from the priests that ***** them when they were boys. Jesus.
- thegsa, on 10/12/2007, -9/+1i still think that they should use really big hepa filters :P
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