Methods of sequestering CO
Methods of sequestering carbon dioxide (CO 2 ) are provided. Aspects of the methods include precipitating a storage stable carbon dioxide sequestering product from an alkaline-earth-metal-containing water and then disposing of the product, e.g., by placing the product in a disposal location or using the product as a component of a manufactured composition. Also provided are systems for practicing methods of the invention.
1. A method of sequestering carbon dioxide, the method comprising:
(i) contacting an alkaline-earth-metal-ion-containing salt water with CO 2 from an industrial waste stream;
(ii) removing protons from said alkaline-earth-metal-ion-containing salt water by an electrochemical protocol, wherein the electrochemical protocol produces no chlorine gas;
(iii) subjecting the alkaline-earth-metal-ion-containing salt water to carbonate compound precipitation conditions to produce a man-made precipitated storage stable carbon dioxide sequestering product; and
(iv) disposing of the precipitated storage stable carbon dioxide sequestering product to sequester carbon dioxide.
2. The method according to claim 1 , wherein the alkaline-earth-metal-ion-containing salt water is neutral or acidic when contacted with the CO 2 from an industrial waste stream.
3. The method according to claim 1 , wherein the alkaline-earth-metal-ion-containing salt water is basic when contacted with the CO 2 from an industrial waste stream, and wherein the pH of the salt water is insufficient to cause precipitation of the storage stable carbon dioxide sequestering product.
4. The method according to claim 3 , wherein the pH of the salt water is maintained at a substantially constant value during contact with the CO 2 from an industrial waste stream.
5. The method according to claim 4 , wherein the pH of the salt water is maintained at the substantially constant value by adding a base to the salt water during contact with the CO 2 from an industrial waste stream.
6. The method according to claim 4 , wherein the pH of the salt water is electrochemically maintained at the substantially constant value.
7. The method according to claim 1 , wherein the electrochemical protocol produces no oxygen gas.
8. The method according to claim 1 , wherein the electrochemical protocol comprises applying a voltage across an anode and a cathode, and produces no gas at the anode.
9. The method according to claim 8 , wherein voltage applied across the anode and cathode is less than 2V.
10. The method according to claim 8 , wherein voltage applied across the anode and cathode is less than 1.5V.
11. The method according to claim 8 , wherein the voltage applied across the anode and cathode is less than 1.0V.
12. The method according to claim 1 , wherein the precipitation conditions produce 50 g or more of the storage stable carbon dioxide sequestering product for every liter of salt water.
13. The method according to claim 1 , wherein the precipitation conditions produce 100 g or more of the storage stable carbon dioxide sequestering product for every liter of salt water.
14. The method according to claim 1 , wherein the precipitation conditions produce 200 g or more of the storage stable carbon dioxide sequestering product for every liter of salt water.
15. The method according to claim 1 , wherein the storage stable carbon dioxide sequestering product comprises from 5 to 14% (w/w) carbon.
16. The method according to claim 15 , wherein the storage stable carbon dioxide sequestering product comprises from 6 to 12% (w/w) carbon.
17. The method according to claim 1 , wherein 10 to 100% of the carbon present in the storage stable carbon dioxide sequestering product is from the industrial waste stream.
18. The method according to claim 17 , wherein 50 to 100% of the carbon present in the storage stable carbon dioxide sequestering product is from the industrial waste stream.
19. The method according to claim 18 , wherein 90 to 100% of the carbon present in the storage stable carbon dioxide sequestering product is from the industrial waste stream.
20. The method according to claim 19 , wherein 95 to 100% of the carbon present in the storage stable carbon dioxide sequestering product is from the industrial waste stream.
21. The method according to claim 1 , wherein the storage stable carbon dioxide sequestering product comprises carbonates.
22. The method according to claim 1 , wherein the carbonates are magnesium carbonates and calcium carbonates.
23. The method according to claim 22 , wherein the weight ratio of magnesium to calcium carbonates in the product ranges from 2-3/1.
24. The method according to claim 1 , wherein the industrial waste stream is a gaseous waste stream produced by one of a power plant, a foundry, a cement plant, a refinery, and a smelter.
25. The method according to claim 24 , wherein the industrial gaseous waste stream is power plant flue gas produced by combustion of a fossil fuel.
26. The method according to claim 25 , wherein the method removes 5% or more of the carbon dioxide from the flue gas with a parasitic energy requirement of 50% or less.
27. The method according to claim 26 , wherein the method removes 10% or more of the carbon dioxide from the flue gas with a parasitic energy requirement of 30% or less.
28. The method according to claim 27 , wherein the method removes 25% or more of the carbon dioxide from the flue gas with a parasitic energy requirement of 25% or less.
29. The method according to claim 25 , wherein the gaseous waste stream comprises one or more of NOx, SOx, VOC, mercury and particulates and the method results in fixation of one or more of the NOx, SOx, VOC, mercury and particulates in the precipitated storage stable carbon dioxide sequestering product.
30. The method according to claim 1 , wherein the alkaline-earth-metal-ion-containing salt water comprises calcium and magnesium.
31. The method according to claim 30 , wherein the salt water comprises brackish water, sea water, or brine.
32. The method according to claim 30 , wherein the method comprises producing the alkaline-earth-metal-ion containing salt water by contacting a precursor water with a source of calcium ions and magnesium ions.
33. The method according to claim 1 , wherein the disposing comprises placing the product at a disposal location.
34. The method according to claim 1 , wherein the disposing comprises employing the product as a component of a manufactured composition.
35. The method according to claim 34 , wherein the manufactured composition is a building material.
36. The method according to claim 35 , wherein the building material is a component of concrete.
37. The method according to claim 36 , wherein the component of concrete is chosen from cement, aggregate and supplementary cementitious material.
38. The method according to claim 37 , wherein the building material is a preformed building material.
39. The method according to claim 34 , wherein the manufactured composition is a non-cementitious composition.