- Number 336 |
- May 2, 2011
Carbon capture, sequestration processes patented
DOE's National Energy Technology Laboratory recently received patents for two carbon capture/sequestration processes.
The first was for an enhanced version of amine-based scrubbing, which couples kinetic rate enhancements with phase separation of CO and chemical regeneration of the amine solution, to separate CO2 from flue gas. As illustrated in the figure, the CO2 is absorbed into an amine-bearing solution containing dissolved sodium or potassium carbonate. The dissolved CO2 reacts with the carbonate to form the corresponding bicarbonate, which precipitates from solution in a semi-crystalline form. The separated bicarbonate solid is then heated to release CO2 and regenerate the carbonate reagent, thus avoiding the energy penalty associated with heating of the bulk amine solution. In an alternative configuration of this novel process, the CO2-loaded amine solutions are used to promote rapid carbonation of solid streams with significant carbonation potential (e.g., waste cement, CaO-bearing fly ash, and other industrial by-product streams). Through this carbonation, CO2 is sequestered as a stable mineral carbonate and the CO2 capture capacity of the amine solution is chemically regenerated.The U.S. Patent and Trademark Office also recently granted NETL a patent (U.S. Patent 7,922,792) for a method to capture and sequester both CO2 and SO2 from waste gas streams using waste by-products, specifically bauxite residue from aluminum production and brine from oil/gas production. The patented acid gas trapping approach combines separation and storage in a single step. The integrated use of bauxite residue/brine mixtures in the process provides a cost effective means of direct flue gas treatment and could be an attractive option for industrial sources located near bauxite residue tailings disposal sites.
[Linda Morton, 304.285.4543,