Capturing Carbon: A Workable Way At Last?

Two wrongs may not make a right, but no one ever said two bads can’t make a good.

The University of Wyoming has recently patented a potentially revolutionary process for combining flue gas—which contains carbon dioxide, sulfur dioxide and mercury—with waste fly ash to produce harmless minerals.

That’s like killing four birds with one stone. Carbon dioxide is a greenhouse gas that contributes to global warming. Sulfur dioxide is a precursor to acid rain and lethal particulates. Mercury is a potent neurotoxin. And fly ash, while much less toxic, can be a disposal nightmare as TVA learned when one of its retention ponds released more than five million cubic yards of the waste material in Tennessee in 2008.

The University of Wyoming process offers a potential solution to the frustrating search for a viable process for carbon capture and storage (CCS). CCS is the holy grail sought by the coal industry and all those who depend on it, as a way to lock up harmful carbon emissions before they damage the planet. Unfortunately, most chemical methods for capturing CO2 emissions are expensive, and underground storage is even more so.

As a result, only a handful of large CCS projects are underway worldwide, and momentum for the entire field is “grind[ing] to a halt,” in the words of Howard Herzog, a CCS researcher at MIT.

Even if scientists and engineers do find a cost-effective solution, public opposition may prevent large-scale storage of CO2 underground, due to worries about gas leakage and possible contamination of water aquifers.

However, researchers led by University of Wyoming Prof. K. J. Reddy say they’ve discovered a way to speed up natural reactions between fly ash, CO2 and other components of flue gases released by the burning of coal. It can be used in new or existing coal-fired power plants as well as steel mills, paper mills, cement plants and others that produce carbon-rich flue gases.

The process promises several enormous benefits: no need for underground pumping and storage of CO2 and very low energy requirements, all at only a fraction of the cost of traditional methods. The byproducts can be used for making concrete and other commercial uses.

Tests at one of the country’s largest coal-fired power plants confirm that it has potential. “We have been supportive of the project and are pleased that the initial results have been positive,” “said Bob Arambel, managing director at PacifcCorp’s Jim Bridger Power Station.

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