Carbon dioxide sequestration involving two-salt-based thermolytic processes
The present invention relates to an energy efficient carbon dioxide sequestration processes whereby Group 2 silicate minerals and CO 2 are converted into limestone and sand using a two-salt thermolytic process that allows for the cycling of heat and chemicals from one step to another.
1. A method of sequestering carbon dioxide produced by a source, comprising:
(a) heating a first halide or hydrate thereof with water to form a first hydroxide, oxide and/or hydroxychloride and HCl, and removing the HCl;
(b) admixing some or all of the first hydroxide, oxide, and/or hydroxychloride with a second halide or hydrate thereof and carbon dioxide to form a first halide or hydrate thereof, a carbonate salt, and water; and
(c) separating some or all of the carbonate salt from step b, whereby the carbon dioxide is sequestered into a mineral product form.
2. The method of claim 1 , wherein the first halide, or hydrate thereof of step (a) is a first chloride.
3. The method according to claim 1 , wherein the first halide or hydrate thereof of step (b) is a first chloride or hydrate thereof.
4. The method of claim 2 , wherein the first chloride or hydrate thereof of step (a) is MgCl 2 .
5. The method of claim 4 , wherein the first chloride or hydrate thereof of step (a) is a hydrated form of MgCl 2 .
6. The method of claim 5 , wherein the first chloride or hydrate thereof of step (a) is MgCl 2 .6H 2 O.
7. The method according to claim 1 , wherein the first hydroxide of step (a) is Mg(OH) 2 .
8. The method according to claim 2 , wherein the first hydroxychloride of step (a) is Mg(OH)Cl.
9. The method of claim 8 , wherein the first step (a) product comprises predominantly Mg(OH)Cl.
10. The method of claim 8 , wherein the first step (a) product comprises greater than 90% by weight Mg(OH)Cl.
11. The method of claim 8 , wherein the first step (a) product is Mg(OH)Cl.
12. The method according to claim 1 , wherein the first oxide of step (a) is MgO.
13. The method according to claim 1 , wherein the second halide or hydrate thereof of step (b) is a second chloride or hydrate thereof.
14. The method of claim 13 , wherein the second chloride or hydrate thereof is CaCl 2 .
15. The method according to claim 3 , wherein the first chloride of step (b) is MgCl 2 .
16. The method of claim 15 , wherein the first chloride of step (b) is a hydrated form of MgCl 2 .
17. The method of claim 15 , wherein the first chloride of step (b) is MgCl 2 .6H 2 O.
18. The method according to claim 1 , where some or all of the water in step (a) is present in the form of steam or supercritical water.
19. The method according to claim 1 , where some or all of the water of step (a) is obtained from the water of step (b).
20. The method according to claim 1 , wherein step (b) further comprises admixing sodium hydroxide.
21. A method of claim 1 , further comprising:
(d) admixing a Group 2 silicate mineral with HCl to form a Group 2 chloride, water, and silicon dioxide.
22. The method of claim 21 , where some or all of the HCl in step (d) is obtained from step (a).
23. The method of claim 21 , wherein the HCl of step (d) further comprises agitating the Group 2 silicate mineral with HCl.
24. The method according to claim 21 , wherein some or all of the heat generated in step (d) is recovered.
25. The method according to claim 21 , where some or all of the second chloride of step (b) is the Group 2 chloride of step (d).
26. The method according to claim 21 , further comprising a separation step, wherein the silicon dioxide is removed from the Group 2 chloride formed in step (d).
27. The method according to claim 21 , where some or all of the water of step (a) is obtained from the water of step (d).
28. The method according to claim 21 , wherein the Group 2 silicate mineral of step (d) comprises a Group 2 inosilicate.
29. The method according to claim 21 , wherein the Group 2 silicate mineral of step (d) comprises CaSiO 3 .
30. The method according to claim 21 , wherein the Group 2 silicate mineral of step (d) comprises MgSiO 3 .
31. The method according to claim 21 , wherein the Group 2 silicate mineral of step (d) comprises olivine (Mg 2 [SiO 4 ]).
32. The method according to claim 21 , wherein the Group 2 silicate mineral of step (d) comprises serpentine (Mg 6 [OH] 8 [Si 4 O 10 ]).
33. The method according to claim 21 , wherein the Group 2 silicate mineral of step (d) comprises sepiolite (Mg 4 [(OH) 2 Si 6 O 15 ].6H 2 O), enstatite (Mg 2 [Si 2 O 6 ]), diopside (CaMg[Si 2 O 6 ]), and/or tremolite Ca 2 Mg 5 {[OH]Si 4 O 11 } 2 .
34. The method according to claim 21 , wherein the Group 2 silicate further comprises iron and or manganese silicates.
35. The method of claim 34 , wherein the iron silicate is fayalite (Fe 2 [SiO 4 ]).
36. The method according to claim 3 , wherein some or all of the first chloride formed in step (b) is the first chloride used in step (a).
37. The method according to claim 1 , wherein the carbon dioxide is in the form of flue gas, wherein the flue gas further comprises N 2 and H 2 O.
38. The method according to claim 1 , wherein suitable reacting conditions of step (a) comprise a temperature from about 200° C. to about 500° C.
39. The method of claim 38 , wherein the temperature is from about 230° C. to about 260° C.
40. The method of claim 38 , wherein the temperature is about 250° C.
41. The method of claim 38 , wherein the temperature is from about 200° C. to about 250° C.
42. The method of claim 38 , wherein the temperature is about 240° C.
43. The method according to claim 1 , wherein suitable reacting conditions of step (a) comprise a temperature from about 50° C. to about 200° C.
44. The method of claim 43 , wherein the temperature is from about 90° C. to about 260° C.
45. The method of claim 44 , wherein the temperature is from about 90° C. to about 230° C.
46. The method of claim 45 , wherein the temperature is about 130° C.
47. The method according to claim 1 , wherein suitable reacting conditions of step (a) comprise a temperature from about 400° C. to about 550° C.
48. The method of claim 47 , wherein the temperature is from about 450° C. to about 500° C.
49. The method according to claim 1 , wherein suitable reacting conditions of step (b) comprise a temperature from about 20° C. to about 100° C.
50. The method of claim 49 , wherein the temperature is from about 25° C. to about 95° C.
51. The method according to claim 21 , wherein suitable reacting conditions of step (d) comprise a temperature from about 50° C. to about 200° C.
52. The method of claim 51 , wherein the temperature is from about 90° C. to about 150° C.