May be too late to correct it and not that it matters anyway, but I noticed a typo in that paper: on page 2,"weather the reaction is performed below or above melting point" should be "whether".
Anyone know how much energy is released by changing a ton of CO2 from pure to diluted in air at ~400 ppm? That is, how much energy would it take to separate CO2 from air if it could be done reversibly? On Apr 19, 6:53 am, "David Keith" <[email protected]> wrote: > Folks, > > Just to put a few of these last comments and perspective. > > There are a handful of groups putting significant effort into air > capture including efforts led by Klaus Lackner (Columbia, GRT), Peter > Eisenberger (Columbia, Georgia Tech, Global Thermostat), Roger Aines > (LLNL) and myself (U-Calgary, Carbon Engineering). > > The groups are at different stages with respect to commercialization and > publication of results. > > All these groups are quite small. Klaus, Roger and I were at a meeting > on the topic in DC on Friday where we estimated that the number of FTEs > now working on air capture is of order 20. These are very small efforts > compared to what would be needed to do detailed engineering and > large-scale testing. > > Speaking for our group, I can say that we are publishing (see enclosed > the latest) and releasing some information (see the website below) but > that as the work becomes more commercial we are slower to release > information because of IP protection. Currently we have subcontracts out > to engineering firms to do design and costing on various subsystems and > we expect to present results for me some of that before the end of this > year. > > The term "artificial trees" is used by Klaus, but not by the other > groups who typically talk about "air capture". Personally, I think > "artificial trees" eye-catching, but a bit misleading since trees do > photosynthesis and make reduced carbon (an advantage) but on the other > hand something that limits the amount of CO2 that can be captured per > unit area (a disadvantage). Industrial air capture, on the other hand, > uses energy to capture CO2 rather producing reduced carbon compounds > directly. More generally, direct air capture competes with biomass with > capture and other methods for producing negative emissions. > > http://www.ucalgary.ca/~keith/AirCapture.html > > Yours, > > David > > ________________________________ > > From: [email protected] > [mailto:[email protected]] On Behalf Of Greg Rau > Sent: April 17, 2009 9:06 AM > To: [email protected] > Subject: [geo] When real trees won't do > > Fake 'trees' designed to trap CO2 > One tower uses resin to trap carbon dioxide; energy industry seen as > buyer > By Eric Bland > Discovery Channel > updated 1:37 p.m. PT, Thurs., April 16, 2009 > A new kind of tree could cool the planet by removing a major greenhouse > gas from the planet's atmosphere. > What researchers are calling artificial trees, actually towers filled > with various materials that adsorb carbon dioxide from the air, could > play a major role in reducing climate change -- if they prove > profitable. > "This is an industry still in its infancy," said Billy Gridley of Global > Research Technologies, LLC, the company creating the C02-scrubbing > towers. "This will eventually rival the size of today's energy markets." > GRT's artificial tree is based on an environmentally friendly resin, > originally developed by Klaus Lackner, a professor at Columbia > University in New York. The alkaline resin reacts with acidic carbon > dioxide, holding it in place. After one hour exposed to the air, the > resin is completely saturated with CO2. > Dry resin soaks up the CO2. Adding water releases the CO2, which is then > captured and stored. Drying the resin again restores its abilities, a > cycle that can be repeated indefinitely. > Over 24 hours Gridley estimates an artificial tree, containing about > 32,800 feet of resin, will harvest about one ton of CO2 each day. > When the first artificial tree is ready, two to three years from now, it > will cost about $150 for each ton, Gridley estimates. When the > technology is fully mature, the price will be as low as $20. > GRT plans to sell the purified CO2 to a range of buyers. Oil and natural > gas companies are probably the biggest customers for the artificial > trees. Petroleum companies pump CO2 underground to raise the pressure > and force oil to the surface. Greenhouses could pump in extra C02 to > help plants grow. Fizzy soda drinks and sanding auto parts also require > concentrated CO2. > All of these customers currently get CO2 by truck or by pipeline, most > of which originates in Texas. The advantage of the artificial trees is > that they can be placed next to whatever factory needs CO2 without > having to ship it in. > Another use for the artificial trees would be in the cap-and-trade > carbon credit system. The idea is that companies that produce CO2 would > pay another company, like GRT, to get rid of it. The most likely place > to put the C02 is in the salt-lined caverns that once held oil, a > process known as carbon sequestration. > Wherever the CO2 is placed, at least it is out of the atmosphere, said > David Keith, a professor at the University of Calgary in Canada, who > developed his own artificial, C02-catching towers years ago and is > working to refine his models. Keith, GRT, and other organizations aren't > trying to profit from climate change; they are looking to prevent or at > least slow it. > "Nobody doubts that this is doable," said Keith. "It's a matter of doing > it at cost, and right now it's still unclear how that can be done." > (c) 2009 Discovery Channel > > 101.Mahamoudkhani.Low-energySodiumHydRec.e.pdf > 752KViewDownload --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. 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