Instead of sequestering carbon dioxide to reduce its effects on global climate, why don’t we split it into harmless carbon and oxygen?
—J. Henderson, Devon, Pa.
James E. Miller, a chemical engineer at Sandia National Laboratories, breaks it down:
Splitting carbon dioxide (CO2) into carbon and oxygen can in fact be accomplished, but there is a catch: doing so requires energy. If hydrocarbon fuels, which produce the greenhouse gas in the first place, supply that energy, thermodynamics tells us that the net result will be more CO2 than you started with.
Consider the proposal as a chemical reaction: CO2 plus energy yields carbon and oxygen. This formula essentially reverses coal combustion (carbon plus oxygen yields CO2 and energy). If energy from coal were applied to drive the decomposition reaction, more CO2 would be released than consumed, because no process is perfectly efficient.
Another option would be to harness a carbon-free energy source to drive a reaction that does not merely undo the combustion process but instead uses carbon dioxide as an input to generate useful, energy-rich products. At Sandia National Laboratories, we are working to apply concentrated sunlight to drive high-temperature thermal reactions that yield carbon monoxide, hydrogen and oxygen from CO2 and water. Carbon monoxide and hydrogen are basic chemical building blocks that find use in producing synthetic fuels, so we call this process “sunshine to petrol.”
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44 Comments
Add CommentWould not a viableoption be to route CO2 rich exhaust gases from coal fired plants to greenhouses? Since the plants thrive on CO2 (ask cops who raid indoor pot growing locations) would this not increase the growth rate for the plants in the greenhouses (e.g. tomatoes, strawberries, spinach) while also reducing the amounts of CO2 released into the air? In Northern climes, where many of the coal fired plants are found, the waste heat from the plant is also useful much of the year. Since many locations are building new coal fired plants, or in some cases they are building greenhouses for other purposes, there would appear to be some synergy here. Certainly there would be issues with ensuring the scrubbers removed harmful sulfer compounds and fly ash (itself useful in concrete production), but the approach should be worthy of investigation.
Reply | Report Abuse | Link to thisSounds good but the amount of CO2 produced during power generation would greatly exceed what could be consumed by the plants within the greenhouse. But I agree that there could be some benefit, not only a CO2 source but also a heat source from all the cooling water used and typically discharged to a lake or river.
Reply | Report Abuse | Link to thisIndeed. If we could use an existing pipeline to pipe the excess CO2 to the northern forests, where it could be consumed & the the oxygen exhalation sent back into the jet stream... that's be an interesting flow system to work out.
Reply | Report Abuse | Link to thisHeat, CO2, fly ash...it's only "waste" if you don't find a use for it. Rem0ving the term, "waste" from our "industrial vocabulary" is the key.
Reply | Report Abuse | Link to thisMy company makes "A" out of "B" and "C" and we are left with "X". Up 'till now my company would just throw "X" into the garbage can and call it good. We can't afford that any more. Our business plan isn't complete until we find a reasonable use for "X".
No, you won't beat entropy but you sure as hell could slow it down a great deal...AND with a bit of planning and a smidge of dumb luck you just might see a bit of EXTRA return on the bottom line.
While I would be suprised if the idea of splitting CO2 actually worked, I don't think this article really answers the question accurately. (Besides avoiding non-co2 generating options like nuclear as the power source.)
Reply | Report Abuse | Link to thisWhen a hydrocarbon is used for energy, one of the by products is co2. There are other products. This question doesn't ask for the recombination of all products. For instance, thw H2O generated from the combustion does not need to be split. The question isn't asking for the entire hydrocarbon chain to be reconstructed.
But the answer is basically saying reconstructing everything would require more energy than generated by a hydrocarbon. The real answer should: Burning 1mol of hydrocarbons generates 2 mols of CO2 and X amount of energy. Splitting 2 mols of CO2 requires Y amount of energy. Y is greater than X so the system is idea is unsound.
But the article fails to prove Y is greater than X.
Commenter bliswell reminds me of a pedagogical problem in science education. Articles don't prove things, they just report them. Science proves itself. That hope that scientific arguments can be so simplified is an oversimplification itself. I am reminded of my physics student who once yelled at me "Shawn, just tell us the answer." He was expecting a formula, derived, as so many poor educators do, on the blackboard; that student never understood that science is a way of thinking, not a collection of rules and formulae. He thought he was a great student, but he was just a memorizer.
Reply | Report Abuse | Link to thisI do agree with bliswell that much of the useful energy comes from the hydrogen and oxygen part of the combustion. There are processes for coal that get at its hydrogen and try to leave the carbon alone. Coking is one such process.
So perhaps, to be clear, bliswell might write "the article confuses the combustion of coal with the combustion of pure carbon."
Also, I was surprised that the answer didn't mention biotic photosynthesis, so I'm glad a commenter did. In fact, there are greenhouses attached to fossil fuel plants. Algal tubes, like those at MIT come to mind.
http://www.csmonitor.com/2006/0111/p01s03-sten.html
Editors are so sloppy these days that the comments on these edited blogs are often better than the articles. Too bad comments can get lost in a long train of themselves.
It seems to me that there is already a process for using solar energy, carbon dioxide, and water to do something...oh, yeah, it is called photosynthesis and when we learn to mimic that process without heat, then we will be onto something!
Reply | Report Abuse | Link to thisI am confused.
Reply | Report Abuse | Link to thisYou admit that using coal energy to fix the CO2 from coal energy will make the problem worse.
You admit there are some inefficiencies in using green energy to fix the CO2 from coal energy.
I would think the best option is to to use green energy to replace current fossil fuel energy. This option, unlike both options above, introduces no inefficiencies. After all the fossil fuels are replaced, if there is still more to do, then your plan would make sense.
Reply | Report Abuse | Link to thisI've been pushing this idea for over a decade. But first let's start by using the coal or any other HC fuel much more eff by gasifying it with steam to make water gas, then burning it with O2 in a gas turbine who's exhaust runs the old coal steam generator which which exhaust drives a low temp Rankine making the condensers very small saving more power, water. This make about 65-70% eff, over double a normal coal plant so using 1/2 the coal making 1/2 the CO2.
This produces almost pure CO2/steam exhaust which heated to high temp by solar turns it into syn gas, H2, CO, which by F-T process turns it into almost any HC you want and electricity. This is basically turning solar into HC fuels and electricity. It's all doable with present tech. They do the F-T part now from stranded NG into diesel.
While it still does release some CO2 it produces a lot of power for what it does. And if the input fuel is biomass, it doesn't add any fossil CO2 as the biomass would end up as CO2 anyway if it wasn't burned.
Energy is needed to split carbon dioxide into carbon and oxygen. In the process of obtaining the required energy, more carbon dioxide might have been produced.
Reply | Report Abuse | Link to thisWhat is the point? Perhaps just do a bit of calculation first.
hey what's up
Reply | Report Abuse | Link to thisthat was a test....My answer to the problem of CO2 would be FORESTS...Russia has those ships that desalinate water with a nuclear reactor and supply a lot of cities with clean water. Plant enough of them around arrid coastlines and get some forests growing, then when they're expanded enough, they'll start creating their own weather....and mandate cities to grow more trees. The heat islands that cities create already raise the temp 10 degrees.
Reply | Report Abuse | Link to thisRather than split it, why not add another element that would render it useful, or at least less toxic?
Reply | Report Abuse | Link to thisInstead of splitting it, why not add an element that would render it harmless, or at least less toxic?
Reply | Report Abuse | Link to thisAs is often the case most commenter's are trying to solve the problem constrained by the rules. That's OK I guess. I liked the biomass comment. You should put it to use because it will become CO2 anyway. Trees aren't the answer they are biomass. I think I saw a paper that said concrete outgases a lot of CO2! Dams for hydro electric generation are big contributors to CO2. The manufacture of Solar Cells out gasses concentrated HFC gas. The answer is in the A+B +(little energy) = X + (big energy) + (waste energy) equation.
Reply | Report Abuse | Link to thisIt is the same thing as good old produce gas. Only the heat source is sunlight instead of coal. Overall, less carbon will be produced than consumed for producing equivalent amount of energy. Rest of the enrgy coming from hydrogen. Interesting to watch engineering involved in using sunlight directly for this endothermic reaction.
Reply | Report Abuse | Link to thisHow much carbon dioxide is in air, and how much of that is man made?
Reply | Report Abuse | Link to thisHellooo??
Reply | Report Abuse | Link to thisThere is a simple solution to the "problem" (not proven factually) of excess CO2 and that is put the trees back.
It takes a lot of trees to make up for one human, but we could readily go back to the use of timber, farmed timber and really make the planet "greener".
The only catch is - like the drugs biz - the money is not in doing the right/sane thing. The "Global Warming " hypothesis is turning into a bigger money-maker than pharmaceuticals...........
Sandia National Laboratories has a long and fabled history in wasting government money in the pursuit of lame ideas.
Reply | Report Abuse | Link to thisAll they need is more money to expand their effort in further studies.
This article shows they have not changed their M O in the last 30 years.
Average bond energies, kcal/mole
Reply | Report Abuse | Link to thisC-H 98
O-H 110
C-C 80
C-O 78
H-H 103
C-N 65
O=O 116 (2 x 58)
C=O 187* (2 x 93.5)
C=C 145 (2 x 72.5)
(* as found in CO2)
If you know anything about hydrocarbon bond energies, you'll see that breaking the C=O bond in CO2 requires more energy than those released forming it. Only way out is to make less CO2, or use a non-hydrocarbon energy source (nuclear, solar, etc) to break the bond. Routing the CO2 to a forest or greenhouse is only marginally better; those green plants are already taking as much CO2 as they can from the atmosphere. Sequestering CO2 is a temporary (albeit 10,000 to 100,000 year) solution. Note that the CO2 emission quantities from power plants and even automobiles are enormous. Not just a few molecules to break up..... The air is about .03% CO2. By the way, CO2 is not the largest contributor to the greenhouse effect. Water vapor is, and there's probably nothing we're going to do about that.......
If you took the carbon dioxide and used it to feed algae as mentioned in a previous comment, and then used the algae directly in bio-composites, and as oil for long term use plastics, you could sequester a lot of carbon really fast. Imagine cars, roads, houses made from algae. I think it might just be possible to build our way out of global warming if we make every durable product we can out of carbon from biological sources.
Reply | Report Abuse | Link to thisI think another use for the carbon that would result from splitting CO2 would be to synthesize diamonds for electrical research. If you dope synthetic diamonds with trace elements (boron, I think, but I'm not sure) they become electrically conductive. If we use synthetic diamonds to create circuits, we can cut the weight of electrical components drastically, which could save energy, especially in machines that use a lot of electrical components. And the oxygen, if not released, could also be used for other things, such as the creation of rocket fuel or some other industrial use. I'm sure that the oxygen and carbon could be sold to companies that would use these substances for such things, which could potentially make splitting CO2 a lucrative venture, and if the energy for splitting CO2 came from solar or nuclear energy, a green one too.
Reply | Report Abuse | Link to thisGreat comment! I have several organic CO2 converters on my property. They are solar powered, they absorb CO2 and give off precious O2. They do require some water to operate, but the maintenance is fairly minimal. One is a Norway maple, and one is an ash.
Reply | Report Abuse | Link to thisThe solution to the problem of carbon storage already exists in the process of photosynthesis. Algae, which is the fastest growing plant, will absorb large amounts of co2 if there is enough of it as a substrate, through which the co2 from coal plants would be funneled. Combine this with sunlight and nutrients from waste and the process will continue in an exponential fashion. The algae can then be converted to biofuel or converted to biochar, both of which can yield more energy. The biochar can be used to increase fertility of the soil to capture more co2 or it can be safely buried. No new technologies are needed, just the infrastructure to combine all of the above.
Reply | Report Abuse | Link to thisThe greatest limiting factor in implementing technology is not, "is it possible?", it is, "is it cost effective?". For example, we could use a replicator, from star trek, to turn CO2 into new food or other organic compounds, except the amount of energy required would be measured in terms of solar output. One of the take-aways from this article is that just because it can be done, doesn't mean it makes good economic sense to do it.
Reply | Report Abuse | Link to thisThe problem we have is that it has been relatively cheap to create all this excess CO2. We didn't pay to create the fossil fuels; the earth did that for us over many millions of years. But unfortunately everyone expects the solution to this problem to be cost competitive with fossil fuel. It’s like this; the spoiled rich kid spends 10% of his inheritance every year and doesn’t do a bit of work. Nine years later he is almost out of money and asks everyone to help him out. They all say, get a job. And he says, no fair, I haven’t had to work these past nine years why should I start now? Instead of pacing himself he blows it all on one last party, then calls his Uncle Sam to bail him out.
idontwantausername asks "Why not replace all the fossil fuels with green energy", unless he/she is refering to nuclear as green ,NOTHING EXISTS that gets the motive power per dollar that petroleum does no matter how many unicorns you ride to the end of the rainbow.The "carbon" thing is a ruse. You cannot plug all the world's volcanoes any more than you can stop breathing.
Reply | Report Abuse | Link to thisidontwantausername asks "Why not replace all the fossil fuels with green energy", unless he/she is refering to nuclear as green ,NOTHING EXISTS that gets the motive power per dollar that petroleum does no matter how many unicorns you ride to the end of the rainbow.The "carbon" thing is a ruse. You cannot plug all the world's volcanoes any more than you can stop breathing.
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Reply | Report Abuse | Link to thisGAGUT:
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G m1m2 - Fr2 = 0
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MC2 - E =0
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G ij,j = 0
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Reply | Report Abuse | Link to thisWe are enclosing a link (http://www.veoh.com/videos/v88753233KEh9Kqp) here showing how after Harvard has studied GAGUT for years, (Harvard University Enriches Top Library with GAGUT Books), a Harvard University highest ranking professor of Astrophysics, Dr. Robert Kirshner in 2007 agreed with the GAGUT SINGULAR ELEMENT DISCOVERY (GSELD) through this video. You will notice in the video, where Professor Kirshner specifically stated "...star fusing Hydrogen to make Helium...Helium is taken three at a time to make Carbon". GAGUT had already previously proven geometrically that Helium is constructed with two Hydrogen units, by Professor G. Oyibo also shown in the video. Therefore when Professor Kirshner stated that “…Helium is taken three at a time to make Carbon” he is actually agreeing with GAGUT clearly that carbon is constructed with six hydrogen units, since the three helium units that make carbon contain two hydrogen units each. This proves that Harvard University, rated as the best university in the world by the Financial Times in London, is learning the GAGUT discovery from the OFAPPIT INSTITUTE OF TECHNOLOGY. That says the other universities and schools are all expected to study GAGUT. You can begin studying GAGUT by calling (631)-242-3069. You can also begin propagating GAGUT globally using the above websites via any media including any appropriate press releases that can be issued by the institution you are associated with as well as through Each One Teach Ten Process. GOD bless you.
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Possible solution to this enwrgy equation, is a clever use of abudant solar energy use. There are some possible solutions.
Reply | Report Abuse | Link to thisActually, the biomass didn't used to end up as CO2 as before the days of humans, large biomasses eventually got burried and turned into....oil and gas...sequestered for millions of years until our grubby little hands showed up.
Reply | Report Abuse | Link to thisUnfortunately, any cycle you care to name that relies primarily on previously sequestered energy (oil and gas) to produce energy adds a net CO2 burden to the planet. Only if an outside, non-carbon based fuel is brought into the picture to perform additional chemical prossessing can you up the ante, so to speak. And, even then, given the energy density of sequestered fuels versus the energy density of solar, wind, wave, it is a net negative scenario. Only nuclear energy can offset the liberation of millions of years of sequestering...and, of course, that carries its own problems.
The ONLY way to avoid liberating vast quantities of sequestered CO2 is to simply not use it and leave it in the ground, or, if you use it, don't burn it for fuel.
can we not use the emiting co2 to an another harmless compound making process?
Reply | Report Abuse | Link to thisIt is extremly good idea, if works efficiently. Definitly it will decrease the load of CO2 upto that extent which may bring the CO2 level at the normal level, decreasing the global warming
Reply | Report Abuse | Link to thisThat's the problem with Scientific American: it avoids any numerical or mathematical analysis of a subject and assumes all its readers are innumerate.
Reply | Report Abuse | Link to thisMaybe as coal meets more restrictions and competition with "new natural gas" the industry will be willing to use their minds, and try your idea. Sounds great. Thanks for your dedication. Hope you are somehow rewarded for your effort.
Reply | Report Abuse | Link to thisWhat do you think of blending biomass and Coal? What are the advantages?
The sequestration of CO2 is an ongoing project for some power companies, but have any scientists considered the consequent effect of irrecoverably burying the oxygen that is part of that CO2? i.e. for every atom of carbon sequestered as CO2, TWO atoms of oxygen will be taken from the atmosphere.
Reply | Report Abuse | Link to thisIf the CO2 is left in the atmosphere, the oxygen will eventually be recovered by photosynthesis. If it is buried, it will be lost forever.
Everyone is asking that carbon dioxide be split up into its components. why not try the reverse, combine the carbon dioxide with something to produce a useful product or at least an inert product to remove it from the enviroment?
Reply | Report Abuse | Link to thisI have read that what makes harmful Carbon Dioxide is the fact when oridnary Carbon mixes with Oxygen. If that is so, what use will it do splitting the harmful Carbon Dioxide?
Reply | Report Abuse | Link to thisGet your energy from the ocean currents, or if you are land locked wind turbines this eliminates any CO2 going into the equation. Then you can split CO2 into carbon and oxygen all day it is quite cheap, due to the fact that you are getting your electricity from the environment.
Reply | Report Abuse | Link to thisI love your username -- it makes me laugh. Idonotwantausername -- I think we should do both. It will likely be many different technologies that finally end the threat of climate change. Anything that helps, helps:)
Reply | Report Abuse | Link to thisAre you saying that to solve climate change you have to deal with water vapor too? Could you explain?
Reply | Report Abuse | Link to thisCommentor InquiringConstructivist is correct. In addition, algae is a scalable concept requiring many times less overhead than greenhouses. In addition some sulfur wastes can be removed by the algae themselves. The algae can have many useful products such as sustainable fertilizer, biofuel, hydrogen sourcing, solid carbon generation, food (gross), et cetra. Too many people have been sold down the river by politicians and pop media that wind, et al, is "the way of the future".
Reply | Report Abuse | Link to thisNobody actually stops to research the situation for themselves. The "Problem" is that people want a quick easy answer that doesn't involve them changing there habits or earning their money a different way. I am NOT a Greenie (and most of those people irritate the crap out of me), but they make valid points about the stuff that gets wasted in this country. Someone could start a very profitable company mining landfills for resources for example. Extracting carbon from air is not an efficient process, but it could be made profitable. There are many ways of extracting carbon from air, but the one that will work is the one that someone monetizes.
Hi, do we know a way increase the concentration of co2 into a container. My thought is to build a economically feasible option ; build a solar based way to absorb co2 from air and build a healthy (for plants) higher co2 concentrated green house (is that the right name) which can help grow better vegetables, fruits may be on roof top. May be mushrooms, herbs, ornamental plants can have better business potential and in course reduce the co2 on air.
Reply | Report Abuse | Link to thisPlease excuse me if this has already been asked.
Reply | Report Abuse | Link to thisIs it possible to use the O2 From Co2 as a fuel sorce to create the power needed to seperate them? My understanding is that there would need to be some type of fuel mixed with the oxygen to create heat, This leads me to a another question can hydrogen/oxygen be used in gas form to create energy? And of coarse we are left with the carbon that can be used in nano carbon tubes. Please point out all the problems I do not understand...Nicely