Capture and Sequestration of Carbon Dioxide in Flue Gases

Abstract

There is provided a process for the capture and sequestration of carbon dioxide that would otherwise enter the atmosphere and contribute to global warming and other problems. CO 2 capture is accomplished by reacting carbon dioxide in flue gas with an alkali metal carbonate, or a metal oxide, particularly containing an alkaline earth metal or iron, to form a carbonate salt. A preferred carbonate for CO 2 capture is a dilute aqueous solution of additive-free (Na 2 CO 3 ). Other carbonates include (K 2 CO 3 ) or other metal ion that can produce both a carbonate and a bicarbonate salt. Examples of suitable metal oxides include several alkaline earths including Cac and MgO. The captured CO 2 is preferably sequestered using any available mineral or industrial waste that contains calcium magnesium or iron in non-carbonate forms, or iron in the Fe +2 oxidation state.

1 - 20 . (canceled) 
     
     
         21 . A system for capturing and sequestering carbon dioxide in carbon dioxide bearing gases of interest comprising:
 (a) a carbon dioxide capture device in the form of a scrubber for receiving and scrubbing said gas of interest using an aqueous carbonate solution to capture carbon dioxide as a bicarbonate in solution; and   (b) a sequestration device for reacting said captured CO 2  with one or more waste materials to form a stable product.   
     
     
         22 . A system as in  claim 21  wherein said sequestration device is designed for a direct reaction with said bicarbonate solution to produce a stable product and a recyclable carbonate solution is regenerated. 
     
     
         23 . A system as in  claim 21  further comprising a regenerator connected to said scrubber for regenerating said carbonate solution from said bicarbonate solution, recirculating said regenerated carbonate solution to said scrubber and sending separated carbon dioxide to said sequestration device. 
     
     
         24 . A system as in  claim 23  including means to pressurize and sequester said captured CO 2  in an unreacted state. 
     
     
         25 . A system for capturing and sequestering carbon dioxide in flue gases of interest comprising a capturing and sequestration vessel for scrubbing the gas of interest and sequestering CO 2  in a single step. 
     
     
         26 . The system as in  claim 21  including a heating device for adding heat to said solution. 
     
     
         27 . The system as in  claim 24  including a heating device for heating said solution. 
     
     
         28 . The system as in  claim 25  including a heating device connected to a regenerator for heating the sequestered CO 2  to drive off gaseous CO 2 .