Posted on 04/11/2002 9:01:33 AM PDT by cogitator
Researchers Look to Mop Carbon Dioxide from Air
ORLANDO, Florida, April 10, 2002 (ENS) - A process under development at Los Alamos National Laboratory (LANL) could extract carbon dioxide (CO2) from the air to help reduce the impact of fossil fuels.
The researchers at the Energy Department lab say the simple, inexpensive technique they are studying could allow for the sustained use of fossil fuels without causing global warming.
The method would allow researchers to harvest CO2 from the air, reducing buildup of the greenhouse gas in the atmosphere and allowing it to be converted into fuel. A Los Alamos led research team presented the research on Tuesday at the annual meeting of the American Chemical Society in Orlando.
"Fossil fuel supplies are plentiful, and what will limit the usage of fossil fuels is the potential climatic and ecosystem changes you may see as a result of rising CO2 levels in the atmosphere," said Los Alamos researcher Manvendra Dubey. "If you can capture atmospheric carbon dioxide, then you limit the environmental impact of fossil fuels and you can continue to use them."
"We have come up with a way to capture and sequester the carbon dioxide that we are putting in the atmosphere," Dubey continued. "Our approach is particularly well suited to capturing CO2 from numerous small sources such as automobiles that are largely being ignored."
The LANL method works on ordinary air, with an average CO2 concentration of about 370 parts per million, rather than capturing the more concentrated emissions found in power plant exhausts. It is believed to be the only available means of capturing the CO2 generated by vehicles, ships and other small sources that account for almost half of all CO2 emissions.
The air is passed over an extraction agent, such as a solution of quicklime, the active agent in some cement. The CO2 in the air reacts with the quicklime and becomes converted to calcium carbonate, or limestone.
Heating the calcium carbonate produces pure carbon dioxide and quicklime, which is recycled back into the extractor. The purified carbon dioxide can be stored or used in industrial applications such as the petrochemical industry, which uses large quantities of it to extract fossil fuels.
"The carbon dioxide comes to the facility on its own," Dubey said. "And because treated air is discharged, the overall concentration of carbon dioxide in the atmosphere gradually decreases over time. Using this method on a large enough scale, it may be possible to return atmospheric carbon dioxide levels to pre-Industrial Age concentrations. Given the possibility our climate system can change abruptly, this possibility is very exciting."
But one question: you have to pass the air over the extraction agent. Don't you have to use fans or pumps to do that? That uses energy. Do you extract more CO2 than you produce from the energy used to force the air?
No, simple diffusion would work just fine. To make the quicklime though, lots of heat needs to be applied. They'll have to go nuclear if they want to avoid generating more CO2 than they collect.
Do you have calculations to back up your statement?
We already have this "device."
Its called a "tree."
It is well established that recently planted trees remove much more CO2 from the atmosphere than "old growth" trees. However, the "green" liberals prohibit the harvesting of old growth forests (to be replaced with new trees) even though this will help remove the CO2 which allegedly causes the "greenhouse effect."
That's a pretty large scale he's talking about! Human activities generate roughly one billion tons of CO2 per year.
Whereupon, the calcium carbonate is regenerated back into lime, releasing the CO2..Where? And it is regenerated back into CO2, How? Well, by heating it. And how is it heated? Umm. Well. By (Mumble) burning fossil fuels.
Soda/Lime sorbents go back at least to the turn of the last century.
Are my tax dollars funding these _stupid_ quacks?!
I rant all the time regarding the decline of the basic Sciences, but for this fraud to have gotten any press at all has proven all my points.
And a National Lab, too.
I think he's an engineer. "All that's required to scale up from the pilot project is a modest investment..."
I meant "It is regenerated back into lime", but was shaking with rage when I typed it.
I expect most Freepers to know that, anyway, so this post is a matter of form!
Bah.
heat of formation for CaO => 152 kcal/mole
heat of form. for CaCO3 => 288 kcal/mole.
So at least 136 kcal will be needed to regenerate(1/8 lb CaO) the quicklime, or make it initialy. That's w/o losses.
136 kcal ~ 544 BTU, or 569k joules, or 220V * 1Amp * 43 min,
or 220V*8A*43min/lb CaO.
I wonder what they are really funding with this tax money. UFO's? Time Travel?
The good thing about it is that it constitutes an oblique attack on the Kyoto Treaty. I've seen other proposed methods for sequestering CO2, and the more ideas that keep popping up, the harder it is for the enviro-socialists to justify radical government controls on energy production and consumption. Their politicized computer models of CO2 increases causing global warming over the next 50-100 years are meaningless if technological advances within the next decade offer the potential of painlessly reducing those CO2 concentrations.
How about geothermal? Convection (heat rising, cooling descending) is your pump, at no energy cost.
I have no idea if global warming is occurring. But, if it is, there is a easily seen culprit:
The Sun.
These environmentalist wackos can't see the Sun in front of their face because there is no political gain from Sun-caused Global Warming. Whereas man-made Global Warming given the the "right" to control the activities of all those who support freedom and fight their plan for total state control.
Another task will be to go around and pick up all the fallen leaves and lawn clippings and bury them before they rot and generate more CO2 and methane (another greenhouse gas). Perhaps Greenpeace will volunteer?
Oh, but they are. You said that they need to go nuclear in order to avoid generating more
CO2 than they collect. Suppose they collect 1 mole of CO2. My calculations say it will take 42 kcals
to regenerate the CaO and the CO2, _which is collected, not allowed to escape_. Now suppose we
burn methane to generate the heat used to regenerate the CaO. Burning a mole of methane
produces one mole of CO2 and _230_ kcals of heat. So, you only have to burn 0.18 moles
of methane, producing 0.18 moles of CO2. There is a net removal of 0.82 moles of CO2 per
mole of methane burned. Here are the equations I used; I got heats of formation from _Handbook
of Chemistry and Physics_, 59th edition:
CaCO3 = CaO + CO2 Delta H reaction = + 42 kcals/mole
CH4 + O2 = CO2 + 2H2O Delta H reaction (combustion) = -230 kcals/mole
Delta H of Formation in Kcals/mole (rounded):
CaCO3 -288
CaO -152
CO2 -94
CH4 -18
H2O -68
CH4 + 2O2 = CO2 + 2H2O Delta H reaction (combustion) = -230 kcals/mole
It's about time we exercised our authority over nature instead of nature and nature cults imposing their ways.
In Europe, after banning the tree killing wood houses, they are now coming back with wood houses in order to trap Carbon in permanent structures....
Moreover, for the short term increased CO2 adds to plant (food) production. A plant's water use becomes more efficient too.
No one has correlated historical temperature changes with CO2 changes. Dear Gorzaloon, I don't mean to be presumptious. You seem like someone who would enjoy the CO2 debate.
1) Has it been truly demonstrated that higher CO2 levels are a bad thing?
2) Why not simply plant more trees? No need to regenerate an absorbant, they clean other real pollutants out of the air, they produce other valuable byproducts (oxygen, food, wood, fuel, etc), they are pleasant to look at, and they are extremely cheap.
3) The chemical industry already has cheap sources of CO2. The manufacture of Ethylene Oxide from oxygen requires CO2 scrubbers and desorbers, which produces a relatively pure source of CO2.
But the energy required can more than easily be offset by massive tax credits, especially if we burn ethanol to make the heat to regenerate the quicklime!
I used to enjoy it till I worked on a DoE energy project for a few years.
There is a B_llsh*t epidemic out there, a veritable TSUNAMI of it!
Many thanks to the Freepers who posted thermodynamic data and balanced equations, not that the people in that Government Lab involved would have the FAINTEST idea what they meant!!!!
I mourn the state of Science Education.
Happy Pleistocene Interglacial!
So it would take:
42 kcal/mole(~1/8 lb)
220V * 1.7A * 1hour/lb.
To burn methane I get the same equation, except I found 58kcal/mole for 2 waters, then 192kcal/mole obtains. That would allow for 78% reduction of CO2 at 100% efficiency. The important part is that in order to generate the CaO, you have to release CO2. So unless someone can make it disappear somehow, it will be released again, causing a 22% increase in CO2 with every cycle. That means 22% released to heat + 100% released to generate the CaO.
Make carbon nanotubes for the space elevator.
By convention, heats of combustion assume water in liquid form is produced. Water in
the gas phase has a heat of formation of -58 kcals/mole. Either way works.
"So unless someone can make it disappear somehow, it will be released again, causing
a 22% increase in CO2 with every cycle"
Unless I missed something, that is the point of the whole project. Once the CO2 is baked
out of the CaCO3, it is stored, in some form. As liquid, for instance. Maybe injected underground
to replace the oil we pump! ;-)
Their politicized computer models are meaningless whatever happens to technological advances. They are useful neither for history matching or prediction.
The oil industry uses a secondary/tertiary recovery method known as Carbon Dioxide Flood, and this seems to be their idea for using the resultant gaseous CO2. I have no idea (nor, apparantly, do they) what the economics might be for obtaining CO2 for flooding in this way.
In any event, they'll need an energy source which in itself doesn't rely on burning hydrocarbons, or it will be a self-defeating idea as a number of posters have noted.
The heat of fusion is ~1.8kcal and the heat of vaporization is 5.5kcal/mole. That's not much over the 42kcal, but the refrigeration required to get it and keep it that way isn't very efficient and will have to be run indefinetely. I'd guess 1.3-1.4 x the normal amount of methane burned just to get it in that form. Any way of storing is just going to take more E. That's why I think nuclear E is the only way to do what they're talking about here. In that case it's better to just use that to begin with.
That brings it to at least 1.29x. In all the prior calcs. efficiencies were 100%. That never occurs. So 0.3x extra methane is the produced for a given quantity frozen. It has to be stored refrigerated to , -76oC, as a solid. If it's a liquid the heat content from 20to -30oC is 15kcal/mole distributed in the 220psi gas and liquid at -30, so that's not as practical as solid store.
So if x amount of CO2 is going to be removed from the atmosphere:
In the 1st step 0.7x is removed and 0.3x released.
In the 2nd step 0.7*0.3x more is removed and (0.3-0.21)x=0.09x is released.
3rd step gets 0.7*0.09x more is removed and 0.09-0.063x=0.027x released. 0.97x gone with 0.42 released sofar.
Another step gives, 0.43x released for each 0.99x removed.
There's nowhere on Earth with those kind of temps for storage, so it has to be very well insulated and refrigerated. That will take more E input on a continuous basis.
And who is to say that "global warming", if it is indeed occurring, is necessarily a bad thing. Especially as we live in what is referred to as an interglacial period...
I should have made it clearer. The intent there was to arrive at a fixed atmospheric content, by removing x amount and adding 0.3x in the process. The extra 0.13 is needed to do that.
Au contraire. Liquid CO2 can be stored at room temperature. CO2 fire extinguishers contain
liquid CO2. One can get cylinders of CO2 with a dip tube so that you can draw off liquid CO2
I have seen photos (in Chemical & Engineering News, I think) of liquid CO2 lying in a pool
on the bottom of the ocean, for Pete's sake!
Anyway, I have shown that it is not impossible to effect a net removal of CO2 from the
atmosphere. There is no violation of the laws of Thermodynamics. As a chemist,
my point is made. The rest is just engineering.
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