An artificial ‘tree’ that captures CO2 a thousand times faster than a real one is the mission objective of Professor Klaus Lackner at Columbia University and also co-founder of Global Research Technologies (GRT) in Tucson, Arizona, USA.
Professor Lackner has been at the forefront of carbon capture and storage since 1995. For some years, Lackner has been proposing a device that traps CO2 directly from the atmosphere using a process similar to sequestration at coal-fired power plants. The CO2 passes over a chemical absorber (the ‘leaves’ of the artificial tree) to which the CO2 molecule attaches.
Professor Lackner estimates that each ‘tree’ with a capture area of 10m by 10m (32.8ft by 32.8ft) can absorb 1,000 tons each year. Similar processes have been around for a long time and is used on spacecraft and submarines to ensure the CO2 does not get to dangerous concentration levels, though these systems are smaller scale.
Once you’ve captured the CO2 on the absorber you then have to provide energy to remove the CO2 molecule, compress it and liquefy it. It seems that Lackner and GRT have found a sorbent material that requires low energy to remove the CO2 molecule and the end-to-end process is purported to be up to 80% efficient when considered in terms of how much CO2 is removed from the atmosphere versus how much is released by the energy production to operate the machine. If the initial energy source is renewable then the process becomes almost CO2 neutral at the front end and a total success at sequestrating CO2 from the atmosphere.
The liquefied CO2 can then be stored underground, down in the deep ocean where it theoretically would stay as liquid carbon dioxide under cold temperature and high pressure, re-used in the pressurisation of oil fields, combined with hydrogen to make synthetic hydro-carbons, fed to oil-making algae or in any of the other chemical and manufacturing processes that require carbon dioxide – like putting it in those fizzy drinks everyone likes. GRT are working on larger scale CO2 scrubbers and currently have some smaller sized ones as working demonstrators.
Many inventions offer much but can’t perform as advertised, usually because someone has over-looked some engineering or scientific limitation – whatever happened to cold fusion? However, if Professor Lackner and GRT are successful, and their machine is capable of performing as advertised then it would seem that humankind may be able to right its wrongs by the appliance of science, engineering, investment and perhaps some luck.
Visit: www.grtaircapture.com
Trevor Williams is a University of Victoria Mechanical Engineering PhD candidate specialising in renewable energy, power grid modelling and plug-in hybrid electric vehicles. He has a bachelors in Aeronautical Engineering, a Masters in Management Science and over 23 years international experience in the space industry, having worked on Earth observation and telecommunications satellites. He is the author of the Eco-Geek blog.
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