The technology behind Alcoa’s DOE backed effort to store CO2 in clay

The Department of Energy as one of its several grants for the beneficial use of CO2 announced that Alcoa and partners would receive roughly $12MM to develop a technology for the use of carbonic anyhydrase based enzyme catalyst and a sodium alkali scrubber to use carbon dioxide to make a carbonate rich clay.  The projects associated with the DOE grant will take place in Point Comfort, Texas.  The technology appears to be closely related to a technology that was patented in 2009 by two Canadians, Sylvie Fradette and Jean Ruel.  That technology is laid out in United States Patent No. 7,596,952 entitled “Process and a plant for recycling carbon dioxide emissions from power plants into useful carbonated species.”  The patent claims exclusivity for some fairly typical characteristics of combustion based power generation when combined with:

“reducing the amount of CO2 contained in the cooled exhaust gas by biologically transforming said CO2 into carbonated species; thereby obtaining a low CO2 exhaust gas, wherein step d) comprises the steps of: catalyzing the hydration of at least a portion of the CO2 contained in the exhaust gas and producing a solution containing hydrogen ions and carbonate ions; and wherein said hydration is catalyzed by the enzyme carbonic anhydrase or an analog thereof.”

In the examples taught within the patent the post combustion cooling appears over and above what would be economical for power generation without any CO2 emission reduction incentives.  At the time of this post it was not clear to the author the exact process that Alcoa was contemplating.  However, the large investment by DOE should serve as an indication that capital expense associated with additional heat exchange and process equipment at least has the possibility of being outweighed by the beneficial products and anticipated incentives to reduce carbon dioxide emissions.