One if by Sea, Two if by Sky: The Search for Affordable CO2 Capture Technology
by Jim Lane (Biofuels Digest) … So, a UCLA team has come up with an interesting angle. Why extract the CO2 from the sky if you can extract it from the sea? Goes the theory, if you pull CO2 from the sea, the oceans will pull down the CO2 from the sky to maintain equilibrium. And, there’s plenty of calcium dissolved in the oceans.
So far, so good.
The researchers outline their concept, dubbed single-step carbon sequestration and storage, or sCS2, in a paper published in the journal ACS Sustainable Chemistry & Engineering.
The proposed technology would incorporate a flow reactor — a system that continuously is fed raw materials and yields products. The seawater would flow through a mesh that allows an electrical charge to pass into the water, rendering it alkaline. This kicks off a set of chemical reactions that ultimately combines dissolved carbon dioxide with calcium and magnesium native to seawater, producing limestone and magnesite by a process similar to how seashells form. The seawater that flows out would then be depleted of dissolved carbon dioxide and ready to take up more. A co-product of the reaction, besides minerals, is hydrogen, which is a clean fuel.
“What’s nice about turning carbon dioxide into a rock is, it’s not going anywhere,” said Sant (senior author Gaurav Sant, director of the UCLA Institute for Carbon Management) , who is a member of the California NanoSystems Institute at UCLA.
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Affordability looks good, though not great
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The name includes “single-step” to differentiate it from other concepts that require carbon dioxide from the atmosphere to undergo a multistep concentration process before it can be stored. And while some plans propose storing captured carbon dioxide in geological formations such as depleted natural oil and gas reservoirs, there is a risk of leaks returning that carbon dioxide into the atmosphere. By contrast, sCS2 is meant to durably store carbon dioxide in the form of solid minerals.
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“We should be clear: Managing and mitigating carbon dioxide is foremost an economic challenge,” Sant said. “Many of today’s approaches for carbon management either require more clean energy than we can produce or are unaffordable. As such, we need to create solutions that are accessible and that will not impoverish the world. We have tried to use a lens of pragmatism to consider how we may be able to achieve synthetic interventions at an unprecedented scale, while considering the finite energy and financial resources we have.” READ MORE
RepAir Carbon realised fuel cell tech could be applied to CO2 capture — now they plan to scale (Yahoo!/TechCrunch)
ISTC-led team to design large-scale system for direct air capture and storage of carbon dioxide in the U.S. (University of Illinois Urbana-Champaign)
