Posting in Aerospace
Aerospace company ATK seeks to sequester CO2 from coal-fire plants by turning it to dry ice. Will the idea cheapen carbon capture costs, or just evaporate?
Rockets are cool, but rocket nozzles may be even cooler. That is, if they live up to the expectations of Alliant Techsystems, or ATK. The aerospace company wants to use the accelerator nozzles to transform carbon dioxide emissions into dry ice.
ATK, partnering with ACENT Laboratories, received $1 million in federal stimulus funding in April, as part of ARPA-E's IMPACCT program (Innovative Materials & Processes for Advanced Carbon Capture Technologies).
Current carbon capture and sequestration (CCS) methods entail chemically separating CO2 from emissions and burying the greenhouse gas underground. The technology is very expensive, but many see it as a way to ween us off coal as we move toward relying more fully on renewable energies.
ATK's approach is akin to what happens when a jet cruises across the sky and leaves a white, icy trail in its wake. But instead of involving atmospheric water vapor and airplanes, ATK's theoretical process will compress CO2 within flue gas and then shoot it through a rocket nozzle at supersonic speeds. As the CO2 escapes the nozzle, the rapidly expanding gas will freeze and precipitate out as dry ice. The idea is that it might then be stored as a solid, treated, or used for commercial purposes.
Discovery News quotes Robert Bakos, vice president of ATK:
Today's carbon capture technology adds 80 percent to the cost per kilowatt hour of electricity delivered. With our approach, we could knock that down to 30 percent.
Within 14 months, ATK hopes to demonstrate their idea in a lab. If successful, a pilot project in a power plant will follow.
Coal-burning power plants currently produce about half our country's electricity, according to the Department of Energy. They also produce a third of our carbon dioxide emissions.
That would be a lot of dry ice.
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Jul 14, 2010
As far as plants absorbing CO2, it's much the same thing as making dry ice--the carbon is not really removed from the active cycle when it's taken up by a plant; it is only captive for the life of the plant. Very few of our plant species live longer than a human being, and whether they are harvested or simply die and rot, their carbon returns to the cycle pretty quickly. Unless we think we can cover the temperate zones of the earth with giant sequoias, plants are not going to get us out of this for any significant length of time. The Only Real Answer is to stop putting fossil carbon into the active cycle. Period. Unless you can get carbon off the planet permanently somehow--but no doubt there would be a downside to that as well. Now, if we could bond the surplus carbon to the radioactive waste from nuclear plants and then somehow put it all away for ten millon years we'd be talkin' business. David, Baltimore
sullivanjc: The amount of CO2 in the atmosphere hasn't been this high for some 15 million years. Back then there were no ice caps, sea levels were much higher, and things were a whole lot different on this planet. Isn't it strange how the _alarmingly high levels of CO2_ that we are recording now sync nicely with the extremely (very tiny tiny) brief man-made industrial revolution spewing CO2 into the air? Yeah, it certainly is.
Nuclear power plants can not be built without massive government subsidies. No private insurance company is willing to insure them so the government has to. Private lenders are not willing to make loans for their construction without government loan guarantees. Because of that alternative energy like wind and solar are already or soon will be less expensive than nuclear power. And Fred, the CO2 that humans, animals and plants emit is not an issue. It is from carbon that is already active in the carbon cycle, not from carbon that has been sequestered from it for millions of years. It's taking carbon that took millions of years to sequester and adding it back in to the carbon cycle in a matter of a couple of hundred years that is the problem. If we only took it out at the rate it was originally sequestered the natural systems that we depend on would be able to adjust without much disruption and it wouldn't be a problem.
Hi Fred.wagner, I completely agree with your post except for 1 thing- nuclear's "only" problem being what to do with the waste. Studies have shown that nuclear is actually carbon intensive- CO2 is released during the building of the plant, maintenance, waste storage,fuel mining/production and de-commissioning, just to name a few of the carbon sources. Also,radioactive effluent is routinely released from nuclear plants, as part of the planned day-to-day operations.Nuclear is also the most water intensive form of energy production, and the most financially risky, with an est. 50% default rate on reactor construction loans. Nuclear plants take 5-20+ years to build, and so cannot reasonably be part of an IMMEDIATE solution to the problem.
To store it as a solid, aren't you going to have to either keep it cold (which requires more energy for cooling) or store it under great pressure (which requires manufacturing containers that can contain such pressures (which requires energy, mining materials, etc...)? Reselling dry ice just means someone else releases CO2 when it melts. . I agree with what someone else said. You need a lot more plants or, failing that a cheap means of large scale artificial photosynthesis to really "fix" things. Then the question becomes, what is the "right" amount of CO2. Historically (long historically) it's been more than an order of magnitude higher which is not so healthy for us but is an 1800 AD level (pre industrial revolution) really the optimum amount, either? A more optimum balance for agricultural growth and human habitation may be a *higher* level of CO2 than now with perhaps some anti-greenhouse gases to keep the temp in check.
CO2 is a problem because of the sheer amount of it emitted through industrial, transportation processes. The normal sequestration processes naturally available (absorption thru plants, the ocean, etc.) have been overwhelmed by the volume, thus raising the percentage in the atmosphere, leading to positive feedback loops that are triggering even more greenhouses being released (methane), leading to further climate change. This is not controversial in the least any more in the scientific community--only in the media, which is interested in selling controversy. Sequestering CO2 in the amounts needed to rebalance the atmospheric fraction to previous levels would be extremely expensive and unfortunately would have to sequester the CO2 for a very long time--centuries if not milllenia. I don't see how you'd maintain frozen CO2 for anywhere long enough of a time to make a significant impact. I'm afraid we're living on a planet whose climate has already changed significantly and will only get worse. For an interesting treatment of what we'll be facing and how to adjust, I'd recommend Bill McKibben's book "Eaarth"
I feel sorry for the journalists on Smart Planet. They post a story that is going to fix all the problems of the world. And then someone who took math and science classes comes along and injects reason into the discussion.
If we're convinced that CO2 emissions really are a problem, nature's way of removing CO2 is really green - PLANTS - they absorb CO2 and release Oxygen. To reduce CO2 levels, stop cutting down rainforests and paving grasslands. Plant more trees that absorb the CO2 - much more practical than stopping breathing. It would be nice to stop burning fossil fuels - solar and wind energy are a step in the right direction, and so is nuclear power - it's only downside is what to do with contaminated byproducts - but we COULD use rocket technology there - shoot them out into the sun - which is an ongoing nuclear reaction. an interesting topic, this is ... (to paraphrase Yoda)...
Eventually, as it is used to cool something else, the solid CO2 (dry ice) will sublimate and go into the atmosphere, but it will be charged to somebody else's carbon account. At this rate, we'll have to start licensing every human and air breathing animal on earth, because we all emit carbon dioxide when we exhale. It's time we recognized this carbon dioxide 'problem' as a distraction which keeps us from solving other real problems, like leaky oil wells, unsafe coal mines, etc.