David, Can I ask if you've considered using a similar approach to remove other GHGs from air?
For example, I've found the following papers which deal with methane adsorption, which may possibly be adaptable to this use. There are other processes which could be used, such as compression heating. 1. http://www.springerlink.com/content/n1h4u85741t6331t/ 2. http://www.mrs.org/s_mrs/bin.asp?CID=6439&DID=175479&DOC=FILE.PDF 3. http://www.etseq.urv.es/lignocarb/seminars/Celzard_UBA_0805.pdf 4. doi:10.1016/S0378-3812(01)00696-3<http://dx.doi.org/10.1016/S0378-3812(01)00696-3> I personally focus on methane, but there are other gases you could also treat. It may be possible to combine the processes to make a general GHG-sucking machine, removing a number of trace gases in a single, multi-stage plant. Kind of like the atmosphere processor depicted in the film 'Aliens'. Further, have you also looked at cooling air to get CO2 to 'snow out' A plant in Siberia or Antarctica which only ran in winter would not have to cool the air much to get this to happen. It could be done by isentropic expansion, thus conserving energy. I'd really value your thoughts, and those of others on the list. Thanks A 2009/12/10 Greg Rau <[email protected]> > Thanks, David. That's a very nice overview that you and Stephens did. > Sorry I missed it earlier. So if air capture via geochem CO2 management > shares some of the same benefits (but with different problems) inherent in > air CCS why was the former approach ignored in you high profile discussion > in Science? Why is air capture only narrowly defined as an industrial means > of producing concentrated CO2 from air, ignoring a variety of geochemical > and biological air capture mechanisms that don't make molecular CO2, some of > which have already absorbed from air about 60% of our CO2 emissions and at > zero cost (but not zero environmental impact)? > Relatedly, I've heard a rumor that APS is sitting on a rather negative > economic assessment of air CCS. Care to offer any insights? > Regards, > Greg > > > Yes, all good. I did not mean to imply that direct air capture was the only > method of abiotic negative emissions, indeed we reviewed a bunch of these > methods in: > > > > Stephens, J. C. and D. W. Keith (2008). Assessing Geochemical Carbon > Management.* Climatic Change*,* 90*: 217-242. You can find it as #75 at > http://*people.ucalgary.ca/~keith/CO2%20Capture%20and%20Storage.html > > > > An interesting fact is that the economics of the CaO in oceans and the > electro-chemical schemes and air capture using strong bases are all linked > by the problem of making or regenerating a strong base with CO2 capture, a > cost that will likely be the dominant cost in each case. > > > > In particular, air capture with a CaO to CaCO3 loop and mining CaCO3 to > make CaO with CO2 capture are very similar, the ocean scheme replaces the > contactor with a ship. > > > > -D > > > > > > ------------------------------ > > *From:* Greg Rau [mailto:[email protected]] > *Sent:* December 10, 2009 9:26 AM > > *To:* David Keith; [email protected]; [email protected] > *Subject:* RE: [geo] Prof. Klaus Lackner + air capture demo at AGU in SF > > > > And just to make clear that there are other alternatives to abiotic air CO2 > capture and storage, I can offer these (attached): > > > > Kheshgi, H. S. Sequestering atmospheric carbon dioxide by increasing ocean > alkalinity.* Energy** 1995*,* 20*, 915-922. > > > > House, K. Z.; House, C. H.; Schrag, D. P.; Aziz, M. J. Electrochemical > acceleration of chemical weathering as an energetically feasible approach to > mitigating anthropogenic climate change.* Environ. Sci. Technol.** 2007*,*41 > *, 8464-8470. > > > > Harvey, L. D. D. Mitigating the atmospheric CO2 increase and ocean > acidification by adding limestone powder to upwelling regions.* J. > Geophys. Res. - Oceans** 2008*,* 113*, doi: 10.1029/2007JC004373. > > > > Rau, G.H. Electrochemical splitting of calcium carbonate to increase > solution alkalinity: Implications for mitigation of carbon dioxide and ocean > acidity.* Environmental Science and Technology* 2008* ,* 42: 8935-8940. > > > > -G > > > > > > > > Manu > > > > Much of what is reported in these articles has little connection with > reality. For example, the economist article states that our system captures > CO2 with a 100 kWhr/tCO2 input, which is dead wrong. We could not get > electricity consumption that low if electricity were the sole energy input, > and in any case we are designing systems that do not import electricity. > > > > I enclose my overview in Science enclosed here: "Why Capture CO2 From The > Atmosphere".* Science*,* 325*: 1654-1655. > > > > We have a longer article that provides a semi-technical overview of the > various trade-offs in the design of air capture systems. See: > > > > David W Keith, Kenton Heidel and Robert Cherry.* Capturing CO2 from the > atmosphere: Rationale and Process Design Considerations*. Geo-Engineering > Climate Change. B. Launder and M. Thompson ed, Cambridge University Press. > > > > There are at least two funded start-up companies developing AC technology > now. I run one of them. Peter Eisenberger runs another. In addition there > are about five academic groups along with Klaus Lackner and GRT. > > > > Some of our stuff, and all publications, are up at > http://**www.**ucalgary.ca/~keith/AirCapture.html, but as the company > speeds up the link between these publications and what we are actually doing > is inevitably getting a bit weaker. > > > > > Yours, > > David > > > > > > > > > > ------------------------------ > > *From:* [email protected] [mailto: > [email protected]]* On Behalf Of* Manu Sharma > *Sent:* December 9, 2009 10:45 PM > *To:* Geoengineering > *Subject:* Re: [geo] Prof. Klaus Lackner + air capture demo at AGU in SF > > > > Thanks Greg. > > > > Apart from the links you provided, members may find the following useful as > well. > > > > First Successful demo of Lackner's > technology<http://**www.**physorg.com/news96732819.html> (Physorg.com > / Apr 2007) > > > > Eminent geochemist Dr. Wallace Broecker endorses Lacker's synthetic > trees<http://**news.bbc.co.uk/2/hi/uk_news/wales/7429562.stm>(BBC) > > > > Interview of Dr. Wallace Broecker discussing the technology (Smithsonian.com) > > <http://**www.**smithsonianmag.com/science-nature/interview-broecker-200806.html> > > > > GRT - the company that's developing the technology with Lackner > <http://**www.**grestech.com/faq.php> > > > > > > It's curious that the expert committee participating in the recent > congressional hearing on Geoengineering contained* three* experts on SRM > but not one on air capture. > > > > Manu > > > > On Thu, Dec 10, 2009 at 6:25 AM, Greg Rau <[email protected]> wrote: > <[email protected]> > > Forwarded from Sarah Brennan: > > > > Prof. Klaus Lackner, director of the Lenfest Center for Sustainable Energy > at the Earth Institute at Columbia University, will be demonstrating air > capture technology at the American Geophysical Union conference in San > Francisco next week (*MailScanner has detected a possible fraud attempt > from "*www.***agu.org" claiming to be* www.***agu.org/meetings/fm09/). > He'll be in booth 103 from Tuesday through Friday -- if you're at the > conference (or just happen to be in San Francisco), please stop by to say > hello. > <http://***www.***agu.org/meetings/fm09/> > > > > -- > > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]<geoengineering%[email protected]> > . > For more options, visit this group at http://** > groups.google.com/group/geoengineering?hl=en. > > -- > > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]<geoengineering%[email protected]> > . > For more options, visit this group at http://** > groups.google.com/group/geoengineering?hl=en. > > > Content-Type: application/octet-stream; > name="AC Science pub.pdf" > Content-Description: AC Science pub.pdf > Content-Disposition: attachment; > filename="AC Science pub.pdf" > > Attachment converted: Macintosh HD:AC Science pub 1.pdf (PDF /CARO) > (028E91F8) > > > > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]<geoengineering%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/geoengineering?hl=en. > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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