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Sunday, March 2, 2008

New Material Could Drop Cost of Carbon Capture

Smokestack Georgia Tech scientists have developed a new material that, combined with the right process, could become the cheapest way to separate the greenhouse gas, carbon dioxide, out of coal plants' smokestacks.

"It's pretty easy and cheap to make and it's got a high capacity for CO2 under realistic conditions," said Chris Jones, a chemical engineer at Georgia Tech.

Those conditions require a material that can trap CO2 out of a mixture of water vapor, nitrogen, and oxygen (among other things), and then release that carbon dioxide on-demand. Being able to do that cheaply remains a dream, and one that some say will always remain "vaporware."

But scientists are pushing on with the effort to develop the right systems to make coal plants outfitted with carbon capture and sequestration cost-competitive with other future power solutions like solar concentrating plants.

Jones' research appears online in the Journal of the American Chemical Society. (Update: Link Fixed. Thanks JMB.)

Two types of materials are seen to have special potential for carbon dioxide separation--zeolites, like Omar Yaghi's ZIFs, and amines. Jones' material is the new top-dog in the latter category because it captures CO2 better than other types of amines and can be used more times (like a longer-lasting sponge). And under real conditions, Jones believes his material could outperform zeolites.

The key challenge is that the material heats up as it traps CO2, then requires heat to release it. In order to be cost effective, he said the heat must be captured and then reused.

"Engineering a process that allows you to capture that heat is the key issue in making this process as cheap as possible," he said. To create a process, he's enlisted fellow Georgia Tech researcher, Bill Koros, to design a new type of so-called filtering bed, which they hope will solve the heat transfer problem.

As we've noted in the past, well-meaning people disagree on whether supporting any sort of coal burning makes sense, but there are two reasons to support carbon capture and sequestration, or the separation and geological burying of carbon dioxide:

Two, biomass burning + sequestration could be a way to actually pull historical CO2 out of the atmosphere. I do, now, have new reservations about biomass, though. Ausra CEO, Bob Fishman, almost had me convinced that biomass was a bad idea. He maintains that you have to grow all the feedstock for the plant ultralocally (like within 50 miles of the plant) to keep the plant environmentally net positive. (And I'm ducking the general biofuel debate that is now raging.)

Original here

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