on sucking carbon: that other mitigation solution
Never mind that this tech is sometimes touted as one means for us to continue spewing carbon. It’s practicality is perversely enhanced by the observation that we’re gonna spew anyway.
Chris Jaeb asked about this approach during a recent seminar session, and I confessed to ignorance…so let’s correct that.
To be fair, significant research has focused on scrubbing carbon out of the air, and best-of-breed seems to be this Columbia University study (via ES&T).
Frank Zeman’s work suggests that it may be feasible to suck CO2 out of the atmosphere using relatively straightforward technology, similar to that currently used by pulp and paper mills.
Industrial-scale scrubbers could pull CO2 from ambient air, and the gas then could be stored by pumping it deep underground or into the ocean.
To its credit, this industrial technology targets the one-half of emissions not coming from large, stationary sources, whereas most recent mitigation research has focused instead on carbon capture and ctorage (CCS) technologies for those large sources.
Still, air capture of CO2 is difficult at best, says Zeman, noting that “the best solution is always to not make the problem in the first place.â€
The wet scrubbing technique absorbs CO2 into a sodium hydroxide solution. The resultant carbonate is transferred from sodium ions to calcium ions via causticization. The captured CO2 is released from the calcium carbonate through thermal calcination in a modified kiln.
Zeman says the process would store more carbon than it burns, though net benefits are limited by the thermal energy demand of the kiln and the mechanical power required for air movement.
As another carbon mitigation technology, Zeman sees air capture allowing for the continued use of liquid hydrocarbon fuels in the transportation sector.
Can’t say that’s a good thang, but…
Oh, and, another salutory feature? ES&T notes that the ultimate plan involves carbon-sucking towers nearly 100 meters tall placed in remote locations where they won’t be eyesores.
Uh…EYESORES? Are we still worried about appearances?
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